Aims

The aims of this study were to determine the effect of osteophyte excision on deformity correction and soft tissue gap balance in varus knees undergoing computer-assisted total knee arthroplasty (TKA).

Aims

The aims of this prospective study were to determine the effect of osteophyte excision on deformity correction and soft- tissue gap balance in varus knees undergoing total knee arthroplasty (TKA).

Aims

The aims of this retrospective study were to determine the incidence of extra-articular deformities (EADs), and determine their effect on postoperative alignment in knees undergoing mobile-bearing, medial unicompartmental knee arthroplasty (UKA).

The extent of soft-tissue release and the exact structures that need to be released to correct deformity and balance the knee has been a controversial subject in primary total knee arthroplasty. Asian patients often present late and consequently may have profound deformities due to significant bone loss and contractures on the concave side, and stretching of the collateral ligament on the convex side. Extra-articular deformities may aggravate the situation further and make correction of these deformities and restoration of ‘balance’ more arduous. These considerations do not apply if a hinged prosthesis is used, as may be warranted in an elderly, low-demand patient. However, in active, younger patients, it may be best to avoid use of excess constraint by balancing the soft-tissues and using the least constrained implant.

Releasing collateral ligaments during TKA has unintended consequences such as the creation of significant mediolateral instability and a flexion gap which exceeds the extension gap; both of these may require a constrained prosthesis to achieve stability. We will show that soft-tissue balance can be achieved even in cases of severe varus, valgus, flexion and hyperextension deformities without collateral ligament release.

The steps are: 1) Determining pre-operatively whether deformity is predominantly intra-articular or extra-articular, 2) Individualizing the valgus resection angle and bony resection depth, 3) Meticulous removal of osteophytes, 4) Reduction osteotomy, posteromedial capsule resection, sliding medial or lateral condylar osteotomy, extra-articular corrective osteotomy, 5) Compensating for bone loss, 6)Only rarely deploying a more constrained device.

Case examples will be presented to illustrate the entire spectrum of varus deformities.

Protrusio acetabuli can be either primary or secondary. Primary or idiopathic protrusio is a rare condition of unknown etiology. Secondary protrusio may be associated with rheumatoid arthritis, ankylosing spondylitis, osteoarthritis, osteomalacia, trauma and Paget's disease. Challenges in surgery include: lack of bone stock, deficient medial support to the cup, difficulty in dislocating the femoral head, and medialization of the hip joint center. Several surgical techniques have been described: use of cement alone without bone graft; morselised impacted autograft or allograft with a cemented cup; metal cages, reinforcement rings, and solid grafts.

We describe our technique of impaction grafting using autologous bone and a cementless porous-coated hemispherical cup without the use of acetabular rings or cages in patients with an average age of 46 years. Protrusion was graded depending on distance of medial wall from Kohler's line as mild (1–5 mm medial), moderate (6–15 mm medial) and severe if it was more than 15 mm medial to the Kohler's line. All patients were operated in the lateral position using a modified Hardinge's anterolateral approach. Adductor tenotomy may be required in cases of severely stiff hips. After careful dislocation of the femoral head, it was sectioned in situ into slivers to facilitate obtaining the graft. The periphery was reamed and care was taken to preserve the membrane lining the floor of the defect. Morselised graft was impacted with hemispherical impactors and the trial cup 1–2 mm larger than the last reamer placed in the desired position. The final socket was then inserted. Femoral preparation was performed in routine fashion.

The mean pre-operative Harris Hip Score of 52 improved to 85 points at a mean follow up of 4 years. The average acetabular inclination angle was 42 degrees. Our results have shown incorporation of the graft in all cases. There was no evidence of progression of the protrusio or cup loosening in any of the cases. Thus far, our hips have not shown osteolytic lesions. The technique described is a satisfactory biological solution of restoring bone stock particularly in young and middle-aged patients.

Since 2005, the author has performed nearly 1000 Oxford medial unicompartmental arthroplasties (UKA) using a mobile bearing. The indications are 1) Isolated medial compartment osteoarthritis with ‘bone-on-bone’ contact, which has failed prior conservative treatment, 2) Medial femoral condyle avascular necrosis or spontaneous osteonecrosis, which has failed prior conservative treatment.

Patients are recommended for UKA only if the following anatomic requirements are met: 1) Intact ACL, 2) Full thickness articular cartilage wear limited to the anterior half of the medial tibial plateau, 3) Unaffected lateral compartment cartilage, 4) Unaffected patellar cartilage on the lateral facet, 5) Less than 10 degrees of flexion deformity, 6) Over 100 degrees of knee flexion, and 7) Varus deformity not exceeding 15 degrees.

Exclusion criteria for surgery are BMI of more than 30, prior high tibial osteotomy, and inflammatory arthritis. All cases were performed with a tourniquet inflated using a minimally-invasive incision with a quadriceps-sparing approach. Both femoral and tibial components were cemented. Most patients were discharged home the next morning; bilaterals usually stayed a day longer.

We have previously described our results and the factors determining alignment. In a more recent study, we have compared the coronal post-operative limb alignment and knee joint line obliquity after medial UKA with a clinically and radiologically (less than Grade 2 medial OA) normal contralateral lower limb. In our series, we have had 1 revision for aseptic loosening of both components, conversion to TKRs in a patient with bilateral UKAs who developed rheumatoid arthritis 3 years later, and 9 meniscal dislocations. There have been no cases of wound infections and thromboembolism. We have reviewed our patients with a minimum 10-year follow-up which will be presented. The vast majority of our patients have been generally very satisfied with the results. Our study shows that most patients (who have no disease in the contralateral knee) regain their ‘natural’ alignment and joint line obliquity comparable to their contralateral limb.

Over the past few years our percentage of UKAs has been steadily rising to about a third of our knee cases. UKA serves as a definitive procedure in the elderly. We see it as a suitable procedure in middle-aged patients who want an operation that provides a quick recovery, full function and range of motion, and near-normal kinematics, with the understanding that they have a small chance of conversion to a total knee arthroplasty in the future.

Lavage and preparation of the cancellous bony surface can facilitate adequate fixation of components in cemented total knee arthroplasty (TKA). Commonly used techniques for bone preparation such as pulse lavage, apart from adding to the cost, may cause local loss of loose cancellous bone and may even drive contaminants deeper into the tissue when used during TKA. We describe a simple, inexpensive and effective tool of using a sterilised toothbrush for preparing bone surface during cemented TKA. This must be followed by adequate pressurization of cement at the right time to achieve close interdigitation of cement with trabecular bone.

Soft-tissue release plays an integral part in primary total knee arthroplasty by ‘balancing’ the knee. Asian patients often present late and consequently may have large deformities due to significant bone loss and contractures medially, and stretching of the lateral collateral ligament. Extra-articular deformities may aggravate the situation further and make correction of these deformities more arduous.

Several techniques have been described for correction of deformity by soft-tissue releases. However, releasing the collateral ligament during TKA has unintended consequences such as the creation of significant mediolateral instability and a flexion gap which exceeds the extension gap; both of these may require a constrained prosthesis to achieve stability. We will show that soft-tissue balance can be achieved even in cases of severe varus deformity without performing a superficial medial collateral ligament release.

The steps are: Determining pre-operatively whether deformity is predominantly intra-articular or extra-articular; Individualizing the valgus resection angle and bony resection depth; Reduction osteotomy, posteromedial capsule resection, sliding medial condylar osteotomy, extra-articular corrective osteotomy; Compensating for bone loss; Only rarely deploying a more constrained device.

Case examples will be presented to illustrate the entire spectrum of varus deformities.

There is enough evidence to show that navigation improves precision of component placement and consistent and accurate restoration of limb alignment, allowing the surgeon to achieve the desired neutral or kinematic alignment. Computer-assisted TKA provides excellent information regarding gap equality and symmetry throughout the knee range of motion. Accurate soft-tissue balancing is facilitated by CAS. It allows precise, quantitative soft tissue release for deformities, especially in knees with severe flexion contractures and severe rigid varus and valgus deformities. It allows accurate restoration of joint line, and posterior femoral offset. Knee arthritis with complex extra-articular deformities and in-situ hardware can be tackled appropriately using computer navigation where conventional techniques may be inadequate. It also allows intra-articular correction for extra-articular deformities due to malunions and facilitates extra-articular correction in cases with severe extra-articular tibial deformities. In obese patients, where the alignment of the limb is difficult to assess, computer navigation improves accuracy and reduces the number of outliers. The ability to quantify the precise amount of bone cuts and soft tissue releases needed to equalise gaps and restore alignment, reduced blood loss, and reduced incidence of systemic emboli improves the safety of the procedure and hastens functional recovery of the patient. Recent evidence shows that the rate of revision especially in younger patients is reduced with navigation.

Aims

The aim of this retrospective study was to measure and determine variation in VCA between the two limbs in a patient with windswept deformity on preoperative full-length, standing, hip-to-ankle radiographs. We hypothesised that there will be significant difference in VCA between the two limbs of a patient with arthritic windswept deformity and therefore it is necessary to individualise VCA for each limb preoperatively on full-length radiographs during TKA.

Aims

Medial unicompartmental knee arthroplasty (UKA) is undertaken in patients with a passively correctable varus deformity. Our hypothesis was that restoration of natural soft tissue tension would result in a comparable lower limb alignment with the contralateral normal lower limb after mobile-bearing medial UKA.

Since 2005, the author has performed 422 Oxford medial unicompartmental arthroplasties (UKA) using a mobile bearing. There were 263 females and 119 males, (40 patients had bilateral UKAs) with a mean age of 62 years.

The indications were: Isolated medial compartment osteoarthritis with ‘bone-on-bone’ contact, which had failed prior conservative treatment; Medial femoral condyle avascular necrosis or spontaneous osteonecrosis, which had failed prior conservative treatment.

Patients were recommended UKA only if the following anatomic requirements were met: Intact ACL, Full thickness articular cartilage wear limited to the anterior half of the medial tibial plateau, Unaffected lateral compartment cartilage, Unaffected patellar cartilage on the lateral facet, Less than 10 degrees of flexion deformity, Over 100 degrees of knee flexion, Varus deformity not exceeding 15 degrees.

Exclusion criteria for surgery were BMI of more than 30, prior high tibial osteotomy, and inflammatory arthritis. All cases were performed with a tourniquet inflated using a minimally-invasive incision with a quadriceps-sparing approach. Both femoral and tibial components were cemented.

Rehabilitation consisted of teaching the patients 6 exercises to regain strength and range of motion, and weight-bearing as tolerated with a cane began from the evening of surgery. Most patients were discharged home the next morning; bilaterals usually stayed a day longer.

We have previously described our results and the factors determining alignment. In a more recent study we have compared the coronal postoperative limb alignment and knee joint line obliquity after medial UKA with a clinically and radiologically (less than Grade 2 medial OA) normal contralateral lower limb. In our series of 423 cases, we have had 1 revision for aseptic loosening of both components, and 4 meniscal dislocations. There have been no cases of wound infections and thromboembolism. We are currently undertaking a review of the 2–10 year follow-up of our cases. The vast majority of our patients have been generally very satisfied with the results. Our study shows that most patients (who have no disease in the contralateral knee) regain their ‘natural’ alignment and joint line obliquity comparable to their contralateral limb.

Over the past few years our percentage of UKAs has been steadily rising. UKA serves as a definitive procedure in the elderly. We see it as a suitable procedure in middle-aged patients who want an operation that provides a quick recovery, full function and range of motion, and near-normal kinematics, with the understanding that they have a small chance of conversion to a total knee arthroplasty in the future.

Soft-tissue release plays an integral part in primary total knee arthroplasty by ‘balancing’ the knee. Asian patients often present late and consequently may have large deformities due to significant bone loss and contractures medially, and stretching of the lateral collateral ligament. Extra-articular deformities may aggravate the situation further and make correction of these deformities more arduous.

Several techniques have been described for correction of deformity by soft-tissue releases. However, releasing the collateral ligament during TKA has unintended consequences such as the creation of significant mediolateral instability and a flexion gap which exceeds the extension gap; both of these may require a constrained prosthesis to achieve stability. We will show that soft-tissue balance can be achieved even in cases of severe varus deformity without performing a superficial medial collateral ligament release.

The steps are: 1. Determining preoperatively whether deformity is predominantly intra-articular or extra-articular; 2. Individualizing the valgus resection angle and bony resection depth; 3. Reduction osteotomy, posteromedial capsule resection, sliding medial condylar osteotomy, extra-articular corrective osteotomy; 4. Compensating for bone loss; 5. Only rarely deploying a more constrained device.

Case examples will be presented to illustrate the entire spectrum of varus deformities.

Lavage and preparation of the cancellous bony surface can facilitate adequate fixation of components in cemented total knee arthroplasty (TKA). Commonly used techniques for bone preparation such as pulse lavage, apart from adding to the cost, may cause local loss of loose cancellous bone and may even drive contaminants deeper into the tissue when used during TKA. We describe a simple, inexpensive and effective tool of using a sterilised toothbrush for preparing bone surface during cemented TKA. This must be followed by adequate pressurization of cement at the right time to achieve close interdigitation of cement with trabecular bone.

During TKA, a surgeon has 4 options: not to use a tourniquet at all, use it from incision to closure, from incision until cementing, and only during cementing. The potential advantages of using a tourniquet are: to reduce blood loss, to have a clear operative field, to facilitate preparation of bony surfaces that are optimal for cementation and longevity of fixation of implants, and to reduce the potential for blood-borne disease transmission through needlestick injuries. Potential disadvantages of tourniquet use have been outlined by the previous speaker. In particular, using a tourniquet from incision until closure has several disadvantages and is generally not a preferred option.

While this paper opposes tourniquetless TKA, it supports using a tourniquet from incision until cementing. We will present in support the findings of our prospective, randomised, double-blind study in patients undergoing cemented, navigated, bilateral simultaneous TKA wherein a tourniquet was used from incision until cementing was complete on one side and compared with the other knee in which a tourniquet was used only during cementing. We compared knee pain, thigh pain, blood loss, hemodynamic changes, functional outcome and complications. We concluded that total knee arthroplasty can be safely and effectively performed with the use of the tourniquet from skin incision until cementing without adverse effects.

Deformity can be associated with significant bone loss, ligament laxity, soft-tissue contractures, distortion of long bone morphology, and extra-articular deformity. Correction of varus, valgus, or flexion deformity requires soft tissue releases in conjunction with bone cuts perpendicular to the long axes of the femur and tibia. Cruciate-retaining or -substituting implants can be used based on surgeon preference if the ligaments are well balanced. However, in presence of severe deformity, additional measures may be warranted to achieve alignment and balance. TKA then becomes a more challenging proposition and may require the surgeon to perform extensive releases, adjunct osteotomies and deploy more constrained implants. Merely enhancing constraint in the implant however without attending to releases and extra-articular correction may not suffice. Certain myths in deformity correction will be presented.

Technical tips with regard to preoperative planning, i.e., whether intra-articular correction alone will suffice or extra-articular correction is required, will be highlighted. Surgical principles and methods of performing large releases, reduction osteotomy, lateral epicondylar sliding osteotomy, sliding medial condylar osteotomy, and closed wedge diaphyseal/metaphyseal osteotomy concomitantly with TKA will be illustrated with examples. Technique of performing TKA with concomitant extra-articular deformity resulting from coronal bowing of femoral or tibial diaphysis, malunited fractures, prior osteotomies, and stress fractures will be presented. The techniques reported can successfully restore alignment, pain-free motion, and stability without necessarily using more constrained implants.

Stems may improve fixation and stability of components during revision total knee replacement. However, the choice between cemented and cementless stems is not a clear one. Cemented stems offer several advantages in terms of versatility, mechanical stability, surgical technique and clinical outcome over their cementless counterpart.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):115–7.

Whether cemented or cementless fixation is superior in TKA is a controversial issue. There are few high quality papers assessing the merits and demerits of cementless and cemented fixation and these will be highlighted. Roentgen stereophotogrammetric analysis (RSA) is an important tool to determine early loosening of components after TKA. There is a high correlation between loosening and early migration of implants seen in the first 2 years after surgery. Hence it is a valuable tool to determine the likelihood of failure in studies with short follow up. Meta-analyses that include papers using RSA are therefore the most valuable and these will be summarised.

In view of the fact that the majority of patients undergoing TKA worldwide are low-demand and elderly persons, in view of the higher cost associated with cementless knees, and the equivalence or superiority of results of cemented TKAs with regards to clinical outcomes and survival in the intermediate term, cemented TKA remains the gold standard in the medium term.

Deformity can be associated with significant bone loss, ligament laxity, soft-tissue contractures, distortion of long bone morphology, and extra-articular deformity. Correction of varus, valgus, or flexion deformity requires soft tissue releases in conjunction with bone cuts perpendicular to the long axes of the femur and tibia. Cruciate-retaining or -substituting implants can be used based on surgeon preference if the ligaments are well balanced. However, in presence of severe deformity, additional measures may be warranted to achieve alignment and balance. TKA then becomes a more challenging proposition and may require the surgeon to perform extensive releases, adjunct osteotomies and deploy more constrained implants. Merely enhancing constraint in the implant, however, without attending to releases and extra-articular correction may not suffice.

Pre-operative planning, i.e., whether intra-articular correction alone will suffice or extra-articular correction is required, will be highlighted. Surgical principles and methods of performing large releases, reduction osteotomy, lateral epicondylar sliding osteotomy, sliding medial condylar osteotomy, and closed wedge diaphyseal/metaphyseal osteotomy concomitantly with TKA will be illustrated with examples. Results of a large series of TKA with extra-articular deformity resulting from coronal bowing of femoral or tibial diaphysis, malunited fractures, prior osteotomies, and stress fractures will be presented. The techniques reported can successfully restore alignment, pain-free motion, and stability without necessarily using more constrained implants.

Lavage and preparation of cancellous bone surface is essential to ensure adequate fixation of components in cemented total knee arthroplasty (TKA). Commonly used techniques for bone preparation such as pulse lavage, apart from adding to the cost, may cause local loss of loose cancellous bone and may even drive contaminants deeper into the tissue when used during TKA. We describe a simple, inexpensive and effective tool of using a sterilised toothbrush for preparing bone surface during cemented TKA.

Protrusio acetabuli can be either primary or secondary. Primary or idiopathic protrusio is a rare condition of unknown etiology. Secondary protrusio may be associated with rheumatoid arthritis, ankylosing spondylitis, osteoarthritis, osteomalacia, trauma and Paget's disease. Challenges in surgery include lack of bone stock, deficient medial support to the cup, difficulty in dislocating the femoral head, and medialisation of the hip joint center. Several surgical techniques have been described: use of cement alone without bone graft; morsellised impacted autograft or allograft with a cemented cup; metal cages, reinforcement rings, and solid grafts.

We describe our technique of impaction grafting using autologous bone and a cementless porous-coated hemispherical cup without the use of acetabular rings or cages in patients with an average age of 46 years. Protrusion was graded depending on distance of medial wall from Kohler's line as mild (1–5mm medial), moderate (6–15mm medial) and severe if it was more than 15mm medial to the Kohler's line. All patients were operated in the lateral position using a modified Hardinge's anterolateral approach. Adductor tenotomy may be required in cases of severely stiff hips. After careful dislocation of the femoral head, it was sectioned in situ into slivers to facilitate obtaining the graft. The periphery was reamed and care was taken to preserve the membrane lining the floor of the defect. Morsellised graft was impacted with hemispherical impactors and the trial cup 1–2mm larger than the last reamer placed in the desired position. The final socket was then inserted. Femoral preparation was performed in routine fashion.

The mean preoperative Harris hip score of 52 improved to 85 points at a mean follow up of 4 years. The average acetabular inclination angle was 42 degrees. Our results have shown incorporation of the graft in all cases. There was no evidence of progression of the protrusio or cup loosening in any of the cases. Thus far, our hips have not shown osteolytic lesions. The technique described is a satisfactory biological solution of restoring bone stock particularly in young and middle-aged patients.

Lavage and preparation of cancellous bone surface is essential to ensure adequate fixation of components in cemented total knee arthroplasty (TKA). Commonly used techniques for bone preparation such as pulse lavage, apart from adding to the cost, may cause local loss of loose cancellous bone and may even drive contaminants deeper into the tissue when used during TKA. We describe a simple, inexpensive and effective tool of using a sterilised toothbrush for preparing bone surface during cemented TKA.

Deformity can be associated with significant bone loss, ligament laxity, soft-tissue contractures, distortion of long bone morphology, and extra-articular deformity. Correction of varus, valgus, or flexion deformity requires soft tissue releases in conjunction with bone cuts perpendicular to the long axes of the femur and tibia. Cruciate-retaining or -substituting implants can be used based on surgeon preference if the ligaments are well balanced. However, in presence of severe deformity, additional measures may be warranted to achieve alignment and balance. TKA then becomes a more challenging proposition and may require the surgeon to perform extensive releases, adjunct osteotomies and deploy more constrained implants. Merely enhancing constraint in the implant however without attending to releases and extra-articular correction may not suffice.

Preoperative planning, i.e., whether intra-articular correction alone will suffice or extra-articular correction is required, will be highlighted. Surgical principles and methods of performing large releases, reduction osteotomy, lateral epicondylar sliding osteotomy, sliding medial condylar osteotomy, and closed wedge diaphyseal/metaphyseal osteotomy concomitantly with TKA will be illustrated with examples. Results of a large series of TKA with extra-articular deformity resulting from coronal bowing of femoral or tibial diaphysis, malunited fractures, prior osteotomies, and stress fractures will be presented. The techniques reported can successfully restore alignment, pain free motion, and stability without necessarily using more constrained implants.

Varus deformity encompasses a wide spectrum of pathology and merits individualised treatment. In most knees there is loss of articular cartilage or bone medially; this is associated with contractures of posteromedial structures of varying rigidity. In addition, there may be significant elongation of lateral ligamentous structures, and associated extra-articular femoral or tibial bowing or angulation. The principles of correction of varus include (i) a thorough clinical and radiological assessment of the limb before surgery and examination under anesthesia, (ii) appropriate bone cuts to correctly orient prostheses and restore normal alignment of the limb, (iii) equalising medial and lateral balance in flexion and extension by soft tissue releases and concomitant bony procedures and (iv) addressing associated bony defects and extra-articular deformity. Examples of each of these situations will be shown along with the technique deployed.

Results of conventional TKA in treating 173 knees with varus deformity exceeding 20o will be presented. Our technique of selective posteromedial release, reduction osteotomy of posteromedial tibial flare, sliding medial condylar osteotomy and bone grafting of medial defects, with preservation of medial collateral ligament integrity will be shown. The method of correcting extra-articular deformity will be depicted. With these techniques, mean tibiofemoral angle of 22.7 degrees varus pre-operatively (range 15–62) was corrected to 5.3 degrees valgus (range 2–9) post-operatively. 86% knees were in 4–10 degrees valgus post-operatively. Recent experience with CAS in treating over 200 patients with deformity exceeding 20 degrees will be presented along with the risk factors leading to malalignment.

Correction of severe varus deformity by the techniques reported can successfully restore alignment, painfree motion, and stability without the use of highly constrained implants.

Protrusio acetabuli can be either primary or secondary. Primary or idiopathic protrusio is a rare condition of unknown etiology. Secondary protrusio may be associated with Rheumatoid Arthritis, Ankylosing spondylitis, osteoarthritis, osteomalacia, trauma and Paget's disease. Challenges in surgery include lack of bone stock, deficient medial support to the cup, difficulty in dislocating the femoral head, and medialisation of the hip joint centre. Several surgical techniques have been described: use of cement alone without bone graft; morsellised impacted autograft or allograft with a cemented cup; metal cages, reinforcement rings, and solid grafts.

We describe our technique of impaction grafting using autologous bone and a cementless porous-coated hemispherical cup without the use of acetabular rings or cages in patients with an average age of 46 years. Protrusion was graded depending on distance of medial wall from Kohler's line as mild (1–5 mm medial), moderate (6–15 mm medial) and severe if it was more than 15 mm medial to the Kohler's line. All patients were operated in the lateral position using a modified Hardinge's anterolateral approach. Adductor tenotomy may be required in cases of severely stiff hips. After careful dislocation of the femoral head, it was sectioned in situ into slivers to facilitate obtaining the graft. The periphery was reamed and care was taken to preserve the membrane lining the floor of the defect. Morsellised graft was impacted with hemispherical impactors and the trial cup 1–2 mm larger than the last reamer placed in the desired position. The final socket was then inserted. Femoral preparation was performed in routine fashion.

The mean pre-operative Harris hip score of 52 improved to 85 points at a mean follow up of 4 years. The average acetabular inclination angle was 42 degrees. Our results have shown incorporation of the graft in all cases. There was no evidence of progression of the protrusio or cup loosening in any of the cases. Thus far, our hips have not shown osteolytic lesions. The technique described is a satisfactory biological solution of restoring bone stock particularly in young and middle-aged patients.

There is ample data to confirm that Computer-assisted total knee replacement improves alignment of the limb when compared with the conventional technique. There is also published evidence that optimum alignment correlates with longevity of implants. CAS enables accurate component alignment of both femoral and tibial components. It enables accurate restoration of the posterior tibial slope which has important consequences for flexion range and stability of the component in flexion especially if mobile bearing implants are considered. CAS also aids in correctly orienting rotation of the femoral component; this has value in minimizing patellar maltracking. We will present our data showing accurate restoration of joint line and posterior femoral offset. As CAS ensures alignment, rotation, sizing and positioning of components, the surgeon is free to devote his efforts to ensuring soft-tissue balance and stability, since TKA is really a ‘soft-tissue’ operation.

How CAS is of immense value in deformity correction and soft-tissue balancing will be illustrated with examples. It helps in better understanding and quantification of the effects of soft-tissue release on flexion-extension gaps and this is of great value not only for minimal deformities (to minimise releases) but also for severe deformities (to ensure complete correction by adequate release). CAS is invaluable in helping equalize flexion-extension gaps; how it can help balance the flexion gap to the extension gap by ‘virtual surgery’ will be depicted with examples. It is particularly useful in presence of hardware in the femur or tibia and for concomitant extra-articular deformity.

We have also found a consistent improvement in recovery of functional milestones with CAS with similar results for both unilateral and bilateral TKAs. Furthermore, there is evidence to support that ensuring alignment has important benefits in improving functional and quality of life scores. In addition, those with alignment of mechanical axis within 3 degrees of normal have been shown to have a shorter stay in hospital by 2 days. Studies have shown reduced blood loss and incidence of emboli after CAS TKA.

Using CAS routinely for all cases, the author is ‘time neutral’. While there is always room for improvement with evolving technologies and CAS is no exception, it already has enormous benefits in the performance and outcome of TKA, and is an important part of the surgical armamentarium for a successful knee arthroplasty.

Navigation has shown to improve limb and component alignment during total knee arthroplasty (TKA). However, most navigation systems involve bulky and expensive hardware, increased operative time and cost. A novel hand-held image-free navigation device has been recently approved with the aim to reduce inventory, cost and surgical time with its small size and quick registration features. We aimed to determine limb and component alignment and validate the accuracy of the iPod based navigation system.

Intraoperative navigation data for proximal tibia and distal femur cuts, femoral component rotation, limb alignment and component alignment in routine imageless navigation system (Ci Navigation, Brainlab) was compared with the novel iPod-based hand-held navigation system (DASH, Smith & Nephew) in 20 TKAs. Postoperative full-length hip-to-ankle and lateral radiographs were evaluated to measure the hip-knee-ankle (HKA) angle and coronal and sagittal alignment of the femoral and tibial component.

The iPod-based navigation system showed good agreement with the Ci Navigation system for limb alignment, tibial and distal femoral cuts in the majority of the limbs despite its quick registration feature. The iPod-based system is hence a positive step towards making navigation systems for TKA more compact, user-friendly, time and cost-effective.

The combination of obesity and malalignment may result in increased revision rates following total knee arthroplasty (TKA). The purpose of this retrospective matched-pair study was to compare the accuracy of limb and component alignment after TKA using conventional versus computer-assisted technique in obese patients. Radiographic data regarding limb alignment, coronal and sagittal component alignment of 72 conventional TKAs (52 patients) were compared with data of a matched group of 72 computer-assisted TKAs. All procedures were performed by a single surgeon, using a single approach and a cruciate-substituting design.

The mean postoperative limb alignment in the conventional group was 177.2° ± 2.5° compared to 179.3°± 1° in the computer-assisted group (p=0.0001). The coronal and sagittal alignment of both femoral and tibial components in the computer-assisted group was significantly accurate compared to the conventional group. In the conventional group, 40.2% of limbs (29 out of 72) had a postoperative HKA angle > ±3° from the neutral compared to 1.3% of the limbs (1 out of 72) in the computer-assisted group (p=0.0001).

Computer-assisted total knee arthroplasty performed in obese patients showed excellent limb and component alignment with very few outliers when compared to conventional total knee arthroplasty. Obesity is an appropriate indication for the use of computer navigation during TKA where use of conventional techniques may result in significant limb and component malalignment.

Excessive under correction of varus deformity may lead to early failure and overcorrection may cause progressive degeneration of the lateral compartment following medial unicompartmental knee arthroplasty (UKA). However, what influences the postoperative limb alignment in UKA is still not clear. This study aimed to evaluate postoperative limb alignment in minimally-invasive Oxford medial UKAs and the influence of factors such as preoperative limb alignment, insert thickness, age, BMI, gender and surgeon's experience on postoperative limb alignment.

Clinical and radiographic data of 122 consecutive minimally-invasive Oxford phase 3 medial unicompartmental knee arthroplasties (UKAs) performed in 109 patients by a single surgeon was analysed. Ninety-four limbs had a preoperative hip-knee-ankle (HKA) angle between 170°-180° and 28 limbs (23%) had a preoperative hip-knee-ankle (HKA) angle <170°. The mean preoperative HKA angle of 172.6±3.1° changed to 177.1±2.8° postoperatively. For a surgical goal of achieving 3° varus limb alignment (HKA angle=177°) postoperatively, 25% of limbs had an HKA angle >3° of 177° and 11% of limbs were left overcorrected (>180°). Preoperative HKA angle had a strong correlation (r=0.53) with postoperative HKA angle whereas insert thickness, age, BMI, gender and surgeon's experience had no influence on the postoperative limb alignment.

Minimally invasive Oxford phase 3 UKA can restore the limb alignment within acceptable limits in majority of cases. Preoperative limb alignment may be the only factor which influences postoperative alignment in minimally-invasive Oxford medial UKAs. Although the degree of correction achieved postoperatively from the preoperative deformity was greater in limbs with more severe preoperative varus deformity, these knees tend to remain in more varus or under corrected postoperatively. Overcorrection was more in knees with lesser preoperative deformity. Hence enough bone may need to be resected from the tibia in knees with lesser preoperative deformity to avoid overcorrection whereas limbs with large preoperative varus deformities may remain under corrected.

Computer navigation has been advocated as a means to improve limb and component alignment and reduce the number of outliers after total knee arthroplasty (TKA). We aimed to determine the alignment outcomes of 1500 consecutive computer-assisted TKAs performed by a single surgeon, using the same implant, with a minimum 1 year follow-up, and to analyze the outliers. Based on radiographic analysis, 112 limbs (7.5%) in 109 patients with mechanical axis malalignment of > 3° were identified and analyzed.

The indication for TKA was osteoarthritis in 107 patients and rheumatoid arthritis in 2 patients. Fifty-eight patients (53%) had undergone simultaneous bilateral TKA and 13 patients (12%) had a BMI >30. Preoperative varus deformity was seen in 100 limbs and valgus deformity in 12 limbs. Thirty limbs (27%) had an extra-articular deformity (2 post HTO limbs, 3 malunited fractures, 1 stress fracture, 21 severe femoral bowing and 3 tibial bowing) and 21 limbs (19%) had severe lateral laxity or subluxation. Thirty-eight limbs (34%) had a preoperative deformity of =10° and 24 limbs (21.5%) had varus or valgus deformity of >20°.

Postoperatively, 11 limbs were malaligned at ±3°, 74 limbs at ±4°, 22 limbs at ±5°, 2 limbs at ±6°, and 2 limbs at ±7°. Coronal plane malalignment of > ±3° of the femoral component was seen in 28 limbs, tibial component in 32 limbs, and both femoral and tibial components in 13 limbs. Twenty-six limbs with preoperative varus deformity had a postoperative valgus alignment of >183° and 3 limbs with valgus deformity had a postoperative varus alignment of <177°.

The incidence of outliers for postoperative limb alignment was low at 7.5% with the tibial component showing a higher incidence of coronal malalignment. Malalignment may be more common in cases of simultaneous bilateral procedures, preoperative limb alignment of =10°, limbs with extra-articular deformities and severe lateral instability. There was a tendency towards over-correction of the hip-knee-ankle axis in both varus- and valgus-deformed knees. Further detailed statistical analysis of the data will be presented.

This is the largest single-surgeon series of consecutive navigated TKAs and consequently the largest analysis of outliers that highlights which knees are likely to fall outside the +3 degrees of acceptable alignment and which therefore behoove the surgeon to exercise greater caution.

The weight bearing axis of the limb goes from the pelvis to the ground and includes the hindfoot. However, the influence of hindfoot alignment on mechanical axis deviation and overall limb alignment after total knee arthroplasty (TKA) is unknown. This study aimed to assess the change in hindfoot alignment after TKA for knee osteoarthritis, the difference in mechanical axis deviation at the knee when calculated using the ground mechanical axis as compared to the conventional mechanical axis, and the effect of hindfoot alignment on the overall postoperative limb alignment after TKA.

We evaluated the pre- and postoperative hip-knee-ankle (HKA) angle, conventional mechanical axis deviation (CMAD), ground mechanical axis deviation (GMAD), and tibiocalcaneal angle (TCA) in 125 patients who underwent 165 consecutive TKAs. Overall, the change in pre- and postoperative mean TCA was not significant (p=0.48) whereas it was significant (p=0.01) in knees with =15° deformity where the hindfoot valgus decreased by approximately 25%. Preoperatively, there was no significant difference between mean CMAD and mean GMAD whereas postoperatively the difference was significant (p=0.0001). Hindfoot valgus alignment of =10° was present in 22.5% of limbs and 29% limbs had a postoperative GMAD of =10 mm in spite of the limb alignment being restored to within 3° of neutral after TKA.

Despite accurate restoration of limb alignment after TKA, as a result of persistent hindfoot valgus alignment the ground mechanical axis may pass lateral to the centre of the knee joint - with potential detrimental effects on bone, ligaments and implants.

Genu recurvatum deformity is uncommon in arthritic knees undergoing total knee arthroplasty (TKA). We retrospectively analysed radiographs and navigation data to determine the clinical and radiographic results of computer-assisted TKA in knee arthritis with recurvatum deformity.

Based on alignment data obtained during computer assisted (CAS) TKA, 40 arthritic knees (36 patients) with a recurvatum deformity of at least 5° were identified. The mean recurvatum deformity was 8.7° (6° to 14°). On preoperative standing hip-ankle radiographs, 23 limbs (57.5%) had a mean varus deformity of 169.4° (153° to 178°) and 17 limbs had a mean valgus deformity of 189.2° (182° to 224°). The intraoperative navigation data showed mean tibial resection of 7.5mm (4.6 to 13.4mm) and distal femur resection of 7.5mm (3.3 to 13mm) with a mean final extension gap of 21.2mm and a flexion gap at 90° of 21.1mm and on extension. On table, the mean knee deformity in sagittal plane was 3° flexion (1.5° to 4.5° flexion).

Postoperatively, the mean HKA angle on standing hip-ankle radiographs was 179.2° (177° to 182°). On postoperative lateral radiographs, joint line in extension was moved distally in 35 limbs by 2.3mm (0.3 to 4mm) and proximally in 5 limbs by 2.2mm (2.2 to 2.4mm); the mean preoperative posterior femoral offset of 28.7 mm changed to 27.9 mm postoperatively. At a mean follow up 28 months (14- 48 months) the knee, function, and pain scores improved by 61, 48, and 28 points, respectively and there was no recurrence of recurvatum deformity at final follow up.

Genu recurvatum is a notoriously difficult condition to address at TKA. The challenges are to be able to detect it at surgery and take appropriate measures in terms of resection and releases to correct it satisfactorily. Computer assisted TKA helps to achieve excellent deformity correction, limb alignment, gap balancing and function in patients with recurvatum deformity by accurately quantifying and helping to modify the amount of bone cuts and titrate soft tissue release.

We retrospectively reviewed the records of 1150 computer-assisted total knee replacements and analysed the clinical and radiological outcomes of 45 knees that had arthritis with a pre-operative recurvatum deformity. The mean pre-operative hyperextension deformity of 11° (6° to 15°), as measured by navigation at the start of the operation, improved to a mean flexion deformity of 3.1° (0° to 7°) post-operatively. A total of 41 knees (91%) were managed using inserts ≤ 12.5 mm thick, and none had mediolateral laxity > 2 mm from a mechanical axis of 0° at the end of the surgery. At a mean follow-up of 26.4 months (13 to 48) there was significant improvement in the mean Knee Society, Oxford knee and Western Ontario and McMaster Universities Osteoarthritis Index scores compared with the pre-operative values. The mean knee flexion improved from 105° (80° to 125°) pre-operatively to 131° (120° to 145°), and none of the limbs had recurrent recurvatum.

These early results show that total knee replacement using computer navigation and an algorithmic approach for arthritic knees with a recurvatum deformity can give excellent radiological and functional outcomes without recurrent deformity.

Extensive release of postero-lateral structures may be required to correct rigid and severe valgus deformities during total knee arthroplasty. Current techniques are technically difficult, may not accurately restore soft tissue balance, and are associated with postoperative complications. We evaluated the results of using computer navigation for lateral epicondylar osteotomy during total knee arthroplasty for rigid severe valgus arthritis.

We had performed this procedure during navigated TKA in 10 valgus arthritic knees (2 bilateral TKAs) in 8 patients (1 male and 7 female). The mean age at the time of surgery was 65.7 years (range, 48–77 years) and the mean preoperative valgus deformity was 19.25° (range, 10°–36.5°). The mean postoperative limb alignment at the end of a mean follow-up of 20 months (range, 14–31 months) was 0.5° valgus (range, 2° varus–1.8° valgus). None of the patients had any complications related to the procedure with no obvious clinical mediolateral instability and complete union at the osteotomy site was noted in all patients radiographically at the last followup.

Computer navigation allows for precisely measuring the difference between medial and lateral gaps as well as the limb alignment and to determine the effect of sequential soft-tissue releases on both. Our technique takes advantage of this feature to accurately re-position the lateral epicondylar block in order to equalize medial and lateral gaps thereby ensuring a stable knee. Internal fixation with compression screws coupled with large contact surfaces of cancellous bone at the osteotomy site allow for early post-operative rehabilitation and ensure union at the osteotomy site.

Total knee arthroplasty becomes more challenging when knee arthritis is associated with an extra-articular deformity of the femur or tibia. We evaluated the outcome of navigated total knee arthroplasty in a large series of arthritic knees with extra-articular deformity.

We retrospectively reviewed the records of 950 patients who had undergone navigated TKA between January 2005 and February 2008. There were 40 extra-articular deformities in 34 patients, with bilateral involvement in 6 patients which were included in the study. Twenty-two limbs had deformity in the femur and the tibia had deformity in 18 limbs. There were 24 females and 10 males with a mean age of 63.1 years (range, 46–80 years).

The etiologies included malunited fractures (13 patients), stress fractures (4 patients), post high tibial osteotomy (3 patients), and excessive coronal bowing (14 patients). The mean femoral extra-articular deformity in the coronal plane was 9.3° varus (range, 24° varus to 2.8° varus) and the mean tibial extra-articular deformity in the coronal plane was 6.3° varus (range, 20° varus to 8.5° valgus). Three limbs underwent simultaneous corrective osteotomy and the rest were treated with intra-articular correction during computer-assisted total knee arthroplasty. The limb alignment changed from a mean of 166.7° preoperatively to 179.1° postoperatively. At a mean follow-up of 26.4 months, the Knee Society knee score improved from a mean pre-operative score of 49.7 points to 90.4 points postoperatively; function score improved from 47.3 points to 84.9 points.

The results of our study indicate that computer-assisted total knee arthroplasty is a useful alternative to conventional total knee arthroplasty for knee arthritis with extraarticular deformity where accurate restoration of limb alignment may be challenging due to the presence of a deformed tibia or femur or in the presence of hardware.

Aim: To determine the factors affecting the blood loss and blood transfusion in primary total knee arthroplasty (TKA)

Patients and methods: A prospective study involving 59 patients, who underwent primary total knee arthroplasty were included. A standardized protocol was used. Patients demographic details, intraoperative blood loss, post operative blood loss, pre-operative and post-operative hemoglobin values on day 1,2,7,14 were recorded.

Results: Average(+/− SD) intraoperative and post operative blood loss were 220(+/−115.6) ml and 443.6 (+/−160.9)ml respectively. Male patients had post-operative blood loss more than female (p= 0.001, students t- test). Patients with rheumatoidarthritic knees and osteoarthritic knees did not show any statistical difference in intraoperative or postoperative blood loss. Tourniquet time and surgical time showed a positive correlation with intraoperative blood loss. Body mass index did not show any correlation with intraoperative or postoperative blood loss. Incidence of blood transfusion was more in patients with rheumatoid knees as the pre operative haemoglobin value was lower in these patients. There was no statistical difference in the incidence of blood transfusion in male and female patients. There was 66% incidence of blood transfusion in patient with pre-operative hemoglobin less then 10.5 gm% . The over all blood loss and blood transfusion incidence were lower in our series when compared to many other series reported in the literature.

Discussion and conclusion: Gender has a role in blood loss in TKA, but diagnosis (OA or RA) has no role. Increase in tourniquet time and surgical time increase the intraoperative and hence the total blood loss. Blood loss and blood transfusion can be reduced to a lower level by following a standardized protocol. Blood transfusion depends on pre-operative hemoglobin rather than intraoperative blood loss. The post operative transfusion trigger can be brought to 8.5 gm% in a haemodynamically stable patient.

We studied 29 girls and one boy with adolescent idiopathic scoliosis who were at Risser grade 0 at the time of posterior spinal fusion and were followed until maturity (mean 7.8 years). We used serial radiographs to measure the ratio of disc to vertebral height in the fused segments and to detect differential anterior spinal growth and assess its effect on scoliosis, vertebral rotation, kyphosis, and rib-vertebral-angle difference (RVAD). From one year after surgery to the latest review, the percentage anterior disc height decreased by nearly one-half and the percentage posterior disc height by nearly one-third in the fused segments (p < 0.001). There was a 4 degree increase in mean Cobb angle (p < 0.001), 11 patients (37%) having an increase of between 6 degrees and 10 degrees. There was a significant increase in mean apical rotation by 2 degrees (p = 0.003), and four patients (13%) had an increase of between 6 degrees and 16 degrees. There was little change in kyphosis. There was an increase in mean RVAD by 4 degrees (p = 0.003), seven patients (23%) showing a reduction by 1 degree to 7 degrees, and 11 (37%) increases of between 6 degrees and 16 degrees. Spinal growth occurs after posterior fusion in adolescents who are skeletally immature, as a result of continued anterior vertebral growth. There is some progression of scoliosis, vertebral rotation, and RVAD, but little change in kyphosis. The increase in deformity is not enough to warrant the use of combined anterior and posterior fusion. The findings are relevant to the management of progressive curves, the timing and extent of surgery, and the prognosis for progression of deformity in this group of patients.

We have used dual-energy X-ray absorptiometry to measure bone mineral density (BMD) in patients with ankylosing spondylitis comparing 41 healthy control subjects and 33 patients with either mild or advanced ankylosing spondylitis. A Norland XR-28 bone densitometer was used to measure the BMD of the lumbar spine and that of the head, trunk, arms, femoral neck, Ward's triangle, legs, pelvis, and total body. Mild ankylosing spondylitis was defined as that showing no or incipient syndesmophytes between L1 and L5 vertebrae: we studied 16 men of mean age 37 years and six women of mean age 37 years. Advanced ankylosing spondylitis, in 11 men of mean age 42 years, showed a bamboo spine with bridging syndesmophytes across all disc spaces between L1 and L5. The mean BMD of the lumbar spine was significantly different in the patients and control subjects of the same sex (0.01 < p < 0.05, analysis of variance), being significantly reduced compared with control subjects in mild disease (0.001 < p < 0.01, t-test) and significantly increased in advanced disease over control subjects (0.01 < p < 0.05; t-test) and over patients with mild disease (0.001 < p < 0.01; t-test). The relevance of these findings to the aetiology and pathogenesis of spinal deformities and other complications in ankylosing spondylitis is discussed.

We studied serial CT scans of 45 arthritic shoulders (34 rheumatoid, 11 osteoarthritic) and 19 normal shoulders, making measurements at three levels on axial images. The maximum anteroposterior diameter of the glenoid was increased in rheumatoid glenoids at the upper and middle levels by 6 mm and in osteoarthritic glenoids at all levels by 5 to 8 mm as compared with normal. In rheumatoid cases, nearly half the available surface of the glenoid was of unsupported bone, mainly posteriorly at the upper and middle levels. In osteoarthritic glenoids, the best supported bone was anterior at the upper level and central at the middle and lower levels. The depth of the rheumatoid glenoid was reduced by a mean of 6 mm at the upper and middle levels and by 3 mm at the lower level. This inclined the surface of the glenoid superiorly. The depth at the middle level in osteoarthritis was reduced by a mean of 5 mm, suggesting central protrusion. Osteoarthritic glenoids were retroverted by a mean of 12.5 degrees, but of rheumatoid glenoids two-thirds were retroverted (mean 15.1 degrees) and one-third anteverted (mean 8.2 degrees). Our findings have important implications for the planning and placement of the glenoid component of total shoulder replacements; CT can provide useful information.

We assessed narrowing of the spinal canal in 39 burst fractures and fracture-dislocations of thoracolumbar vertebrae treated by the AO Internal Spinal Fixator, using CT preoperatively and at various stages postoperatively. Computer-aided planimetry was used to measure the narrowing, and its restoration shortly after instrumentation, or at 15 months. The mean initial reduction of canal area was to 63.7% +/- 18.8% of normal; this was restored to a mean of 95.4% +/- 21.2% of normal when measured either soon after surgery or at 15 months (p < 0.001 for both groups). There was more improvement in cases assessed later. For fractures from D12 to L3, the mean canal area was restored to 99.4% of normal; but at L4 or L5 the mean restitution was to only 60.9% (p < 0.05). We found no correlation between preoperative loss of area and amount of restoration, or severity of neurological deficit. Nor was there any correlation between the delay before surgery and the improvement achieved. The mechanism of fracture reduction appears to be a combination of distraction ligamentotaxis and forced hyperextension.

We describe a management strategy for upper- and lower-limb fractures with associated arterial injury and report the results in 113 cases treated over a period of 18 years. Primary amputation was performed in 23 patients and of those who underwent primary vascular repair, 27 needed secondary amputation, two-thirds of them within a week of the injury. Of those requiring secondary amputation, 51.8% had ischaemia exceeding six hours, 81.4% had severe soft-tissue injury and 85.2% had type III open fractures. The patients whose limbs had been salvaged were followed up for an average of 5.6 years. The eventual outcome depended on the severity of the fracture, the degree of soft-tissue damage, the length of the ischaemic period, the severity of neurological involvement, and the presence of associated major injuries. There was a 30% incidence of long-term disability in the salvaged limbs, largely due to poor recovery of neurological function. Prompt recognition of such combined injuries is vital and requires a high index of suspicion in patients with multiple injuries and with certain fracture patterns. We recommend a multidisciplinary approach, liberal use of pre-operative angiography in upper-limb injuries and selective use of intra-operative angiography in lower-limb injuries. Stable external or internal fixation of the fractures and re-establishment of limb perfusion are urgent surgical priorities to reduce the period of ischaemia which is critical for successful limb salvage.

One hundred and fifty asymptomatic shoulders in 75 schoolchildren were studied. The shoulders were tested for instability and a hyperextensometer was used to assess joint laxity. Signs of instability were found in 57% of the shoulders in boys and 48% in girls; the commonest sign was a positive posterior drawer test which was found in 63 shoulders. A positive sulcus sign was found in 17 shoulders and 17 subjects had signs of multidirectional instability. General joint laxity was not a feature of subjects whose shoulders had positive instability signs.