Introduction

The aim of this study was to quantify mid-flexion laxity in a total knee arthroplasty with an elevated joint line, as compared to a native knee and a TKA with joint line maintained. Our hypothesis was joint line elevation of 4mm would increase coronal plane laxity throughout mid-flexion in a pattern distinct from the preoperative knee or in a TKA with native joint line.

Controversies about the management of injuries to the soft tissue structures of the posteromedial corner of the knee and the contribution of such peripheral structures on rotational stability of the knee are of increasing interest and currently remain inadequately characterised. The posterior oblique ligament (POL) is a fibrous extension off the distal aspect of the semimembranosus that blends with and reinforces the posteromedial aspect of the joint capsule. The POL is reported to be a primary restraint to internal rotation and a secondary restraint to valgus translation and external rotation. Although its role as a static stabiliser to the medial knee has been previously described, the effect of the posterior oblique ligament (POL) injuries on tibiofemoral stability during Lachman and pivot shift examination in the setting of ACL injury is unknown.

The objective of this study was to quantify the magnitude of tibiofemoral translation during the Lachman and pivot shift tests after serial sectioning of the ACL and POL.

Eight knees were used for this study. Ligamentous constraints were sequentially sectioned in the following order: ACL first, followed by the POL. Navigated mechanised pivot shift and Lachman examinations were performed before and after each structure was sectioned, and tibiofemoral translation was recorded.

Lachman test: There was a mean 6.0 mm of lateral compartment translation in the intact knee (SD = 3.3 mm). After sectioning the ACL, translation increased to 13.8 mm (SD = 4.6; P<0.05). There was a nonsignificant 0.7 mm increase in translation after sectioning the POL (mean = 14.5 mm; SD = 3.9 P>0.05).

Mechanised pivot shift: Mean lateral compartment translation in the intact knee was −1.2 mm (SD = 3.2 mm). Sectioning the ACL caused an increase in anterior tibial translation (mean = 6.7 mm; SD = 3.0 mm; P<0.05). No significant change in translation was seen after sectioning the POL (mean = 7.0 mm, SD = 4.0 mm; P>0.05).

Sectioning the POL did not significantly alter tibiofemoral translation in the ACL deficient knee during the Lachman and pivot shift tests. This study brings into question whether injuries to the POL require reconstruction in conjunction with ACL reconstruction. More studies are needed to further characterise the role of the injured POL in knee stability and its clinical relevance in the ACL deficient and reconstructed knee.

Controversies about the management of injuries to the soft tissue structures of the posteromedial corner of the knee and the contribution of such peripheral structures on rotational stability of the knee are of increasing interest and currently remain inadequately characterised. The posterior oblique ligament (POL) is a fibrous extension off the distal aspect of the semimembranosus that blends with and reinforces the posteromedial aspect of the joint capsule. The POL is reported to be a primary restraint to internal rotation and a secondary restraint to valgus translation and external rotation. Although its role as a static stabiliser to the medial knee has been previously described, the effect of the posterior oblique ligament (POL) injuries on tibiofemoral stability during Lachman and pivot shift examination in the setting of ACL injury is unknown.

The objective of this study was to quantify the magnitude of tibiofemoral translation during the Lachman and pivot shift tests after serial sectioning of the ACL and POL.

Eight knees were used for this study. Ligamentous constraints were sequentially sectioned in the following order: ACL first, followed by the POL. Navigated mechanised pivot shift and Lachman examinations were performed before and after each structure was sectioned, and tibiofemoral translation was recorded.

Lachman test: There was a mean 6.0 mm of lateral compartment translation in the intact knee (SD = 3.3 mm). After sectioning the ACL, translation increased to 13.8 mm (SD = 4.6; P<0.05). There was a nonsignificant 0.7 mm increase in translation after sectioning the POL (mean = 14.5 mm; SD = 3.9 P>0.05).

Mechanised pivot shift: Mean lateral compartment translation in the intact knee was −1.2 mm (SD = 3.2 mm). Sectioning the ACL caused an increase in anterior tibial translation (mean = 6.7 mm; SD = 3.0 mm; P<0.05). No significant change in translation was seen after sectioning the POL (mean = 7.0 mm, SD = 4.0 mm; P>0.05).

Sectioning the POL did not significantly alter tibiofemoral translation in the ACL deficient knee during the Lachman and pivot shift tests. This study brings into question whether injuries to the POL require reconstruction in conjunction with ACL reconstruction. More studies are needed to further characterise the role of the injured POL in knee stability and its clinical relevance in the ACL deficient and reconstructed knee.

Unicompartmental knee replacement (UKR) has good outcomes for the treatment of compartmental osteoarthritis of the knee. Mechanical alignment overcorrection is associated with early failure of the femoral and tibial components. Preoperative mechanical alignment is the most important predictor of postoperative alignment. However, most studies do not take into consideration the magnitude of preoperative deformity when reporting on mechanical alignment outcomes after UKR.

We aimed to determine the magnitude of postoperative mechanical alignment achieved based on the magnitude of preoperative alignment; and to compare the number of cases of overcorrection into valgus to historical data.

This was a radiographic review of patients who underwent robotic medial UKR by a single surgeon between 2007 and 2011. Two examiners measured pre- and postoperative mechanical alignment for all patients on long-leg radiographs. Patients were classified into three groups of preoperative mechanical alignment: mild varus (0–5®); moderate varus (5–10®); and severe varus (>10®). Patients with valgus alignment (<0®) were excluded. Linear regression was used to estimate the magnitude of postoperative alignment for each group, adjusting for age, BMI, gender, side, implant type, and polyethylene thickness.

89 patients were included. Mean preoperative alignment was 7.3® varus (95% CI = 6.6®–8®; range, 0.1–15® varus). Mean postoperative alignment was 2.8® varus (95% CI = 1.9®–3.8®; range, 1.4® valgus–9.7® varus). There was a significant difference in postoperative mechanical alignment between the three groups (Table 1) (P<0.05). Four overcorrections (4.5%) were detected, all under 1.5® valgus. This percentage of overcorrection was significantly better than previous conventional UKR reports (mean = 12.6%; P = 0.04).

The magnitude of postoperative alignment in medial UKR depends on the severity of the preoperative deformity. Reports on radiographic outcomes of UKR should be stratified by the magnitude of preoperative alignment. The risk of overcorrection is reduced when using robotic assistance compared to using the conventional manual technique.

The anterior femoral cortical line (AFCL) is an anatomical landmark which has been used by the senior author for 20 years to assess femoral rotation in over 4000 TKR's. The AFCL describes the alignment of the anterior cortex of the distal femur proximal to the trochlear articular cartilage.

The AFCL was compared with the surgical epicondylar (SEA), anteroposterior (Whiteside's line) and posterior condylar (PC) axes using 50 dry-bone cadaveric femora, 16 wet cadaveric specimens, 50 axial MRI's and 58 TKR patients intra-operatively.

In the dry-bone/cadaveric femora (measuring relative to the SEA the AFCL and Whiteside's AP axis were 1° externally rotated and the PC axis was 1° internally rotated. By MRI (relative to the SEA) the AFCL was 8° internally rotated, Whiteside's was 2° externally rotated and the PC axis was 3° internally rotated. In the clinical study (measuring relative to a perpendicular to Whiteside's line alone) the AFCL was 4° degrees internally rotated, which equates to 2-3° of internal rotation relative to the SEA.

The AFCL is another axis, completing the ‘compass points’ around the knee. It may prove particularly useful when one or all of the other reference axes are disturbed such as in revision TKR, lateral condylar hypoplasia or where there has been previous epicondylar trauma. We suggest building in 5° external rotation with respect to the anterior femoral cortical line for femoral component rotation.

Background: The purpose of this study was to assess the anterior femoral cortical line (AFCL) as an additional anatomical landmark for determining intraoperative femoral component rotation in total knee arthroplasty. The AFCL was compared with the Epicondylar axis, the anteroposterior (AP) axis (Whiteside’s line), and the posterior condylar axis. Dry bone, cadaver, MRI and intra-operative measurements were compared.

Methods: Fifty dry bone femora, and 16 wet cadaveric specimens were assessed to identify the AFCL and this was compared against the 3 reference axes discussed above. Photographs were taken of the specimens with K-wires/marker pins secured to the reference axes and then a digital on-screen goniometer was used to determine the mean angular variations with respect to the Epipcondylar axis.

In the clinical trial, 58 consecutive patients undergoing total knee arthroplasty were included. After a routine exposure the AP axis was marked on each distal femur. The AFCL was then identified and the anterior femoral cortical cut was made parallel to this line. The angle between this cortical cut and the perpendicular to the AP axis was measured using a sterile goniometer.

In the MRI study, 50 axial knee images were assessed and the most appropriate slice/s determined in order to identify the AFCL and the other 3 reference axes and then their relationship was measured by an on-screen goniometer.

Results: In the cadaveric study the AFCL was a mean 1° externally rotated to the epicondylar axis (SD = 5°), White-side’s line was 1° externally rotated (SD = 4°) and the posterior condylar axis was 1° internally rotated (SD = 2°)

By MRI and with respect to the epicondylar axis, the AFCL was a mean 5° externally rotated (SD= 3), White-side’s Line was 1° externally rotated (SD = 2) and the posterior condylar axis was 3° internally rotated (SD = 2).

In the clinical study in 8 patients it was impossible to draw the AP axis because of dysplasia or destruction of the trochlea by osteoarthrosis. In the remainder the mean difference between the anterior femoral cortical line and Whiteside’s AP axis was 4.1 degrees internally rotated (SD = 3.8°). The lateral release rate for this cohort was 4%.

Conclusion: The anterior femoral cortical line provides an additional reference point, completing the ‘compass points’ around the knee. It has been shown in this study to be reliable in the laboratory, on MRI and in a clinical setting for assessing rotation of the femoral component. It may prove particularly useful when one or all of the other reference axes are disturbed such as in revision TKR, lateral condylar hypoplasia or where there has been previous epicondylar trauma.

Purpose: To assess the anterior femoral cortical line (AFCL) as an additional anatomical landmark for determining intraoperative femoral component rotation in total knee arthroplasty. The anterior femoral cortical line (AFCL) is an anatomical landmark which has been used by the senior author for 20 years to assess femoral rotation in over 4000 TKRs. The AFCL describes the alignment of the anterior cortex of the distal femur proximal to the trochlear articular cartilage.

Methods: The AFCL was compared with the surgical epicondylar axis (SEA), anteroposterior axis (Whiteside’s line) and posterior condylar (PC) axis using 50 dry-bone cadaveric femora, 16 wet cadaveric specimens, 50 axial MRI scans and 58 TKR patients intra-operatively.

Results: In the dry-bone and cadaveric femora (measuring relative to the SEA) the AFCL and Whiteside’s AP axis were 1° externally rotated and the PC axis was 1° internally rotated. With MRI (relative to the SEA) the AFCL was 8° internally rotated, Whiteside’s was 2° externally rotated and the PC axis was 3° internally rotated. In the clinical study (measuring relative to a perpendicular to Whiteside’s line alone) the AFCL was 4° degrees internally rotated, which equates to 2–3° of internal rotation relative to the SEA.

Conclusion: The AFCL is another axis, completing the ‘compass points’ around the knee. It may prove particularly useful when one or all of the other reference axes are disturbed such as in revision TKR, lateral condylar hypoplasia or where there has been previous epicondylar trauma. We suggest building in 5° external rotation with respect to the anterior femoral cortical line when judging femoral component rotation.

Introduction: Stiffness following Total Knee Arthroplasty is a serious and debilitating complication. There are many different patient and surgical factors implicated in it cause. Previous studies have suggested that it will occur in approximately 1% of TKR patients. Arthrofibrosis is an uncommon but potentially debilitating cause in an otherwise well positioned implant. The cause of this abnormal scar formation is as yet unknown. The treatment of this condition remains difficult and controversial. Revision of the TKR has been suggested as the gold standard treatment as other operative strategies have had limited success. Our approach to this problem has been to conserve the prosthesis and try to release the scar tissue.

Aim: The aim of this study is to assess the results of open arthrolysis in the treatment of established arthrofibrosis.

Method: 1522 patients undergoing primary uncemented TKR have been prospectively followed up (2022 TKR’s) using the International Knee Society Scores. 13 patients underwent open Arthrolysis for stiffness post-op (Incidence 0.64%). The average age was 65 (range 50–78). 6 cases were simultaneous bilateral procedures (Incidence 1.2% of simultaneous bilateral procedures). The average time between TKR and arthrolysis was 14 months. Our average follow-op was 7.2 years (range 2 – 10 years)

Results: The average ROM just prior to Arthrolysis was 58°. The average ROM six months after surgery had improved to 91° (p< 0.05). The average ROM at last follow-up was 95° (p< 0.05) with an average Knee Society score of 155 (pain 83, function 72).

No patients have required revision of their components.

Conclusions: We have found open arthrolysis a successful approach to post-op arthrofibrosis. Although a large procedure it has been well tolerated by our patients. They have had an improvement in range of movement by six months which has been maintained up to 10 years.

Introduction The efficacy of total knee replacement (TKR) surgery is well documented throughout the literature. Results from cemented and cementless series reveal similar long-term reliable results in terms of function and survival. Less, however, is known of the long-term results of uncemented TKR with the use of hydroxyapatite (HA). The purpose of this paper is to present the long-term results of a series of TKR using an uncemented, HA-coated, PCL retaining prosthesis.

Method During the period from August 1992 to December 1994 all patients undergoing TKR surgery were prospectively recorded in a consecutive series. Results were recorded pre- and post-surgery at regular intervals (both clinically and radiographically). The combined clinical Knee Society Score was used to evaluate outcome with routine radiographic evaluation done at 10 years.

Results 217 patients (126 female, 91 male) were included in the study with 322 knees in total (75 simultaneous bilateral, 23 staged bilateral and 126 unilateral). The mean age was 70 years (range 34–88 years) with a mean follow-up of 11 years (range 10–12 years). 47 (21.7%) patients were deceased at 10 years. The principle indication for surgery was osteoarthritis. There has been 1 revision (0.3%) for infection in this series to date. There have been 7 (2.2%) deep infections requiring surgical intervention and 4 (1.2%) supracondylar fractures.

At 10 years, mean knee score was 174 with range of movement 0–111 degrees. 95.4% of the series has currently been successfully followed up. 9 patients were unable to be contacted and lost to follow up. With revision as an end point, the rate of survival for the prosthesis at 10 years is 99.4%. Assuming worst case scenario for patients lost to follow up, survivorship is 95.4%.

Conclusion The survival of this prosthesis has shown to compare favourably to other published results. A low rate of revision and infection combined with excellent clinical and functional outcomes suggests the use of HA with an uncemented TKR produces reliable long-term results.

Introduction and Aims: Use of bioceramic coatings to enhance fixation of joint arthroplasties is a relatively new concept that has yet to prove long-term, reliable results in knee arthroplasty. The purpose of this study was to prospectively report on the medium- to long-term outcomes of an uncemented, hydroxyapatite coated total knee replacement (TKR).

Method: Between August 1992 and 2002 all patients in a consecutive series requiring primary TKR were treated with an uncemented, hydroxyapatite coated, posterior cruciate ligament retaining prosthesis implanted by the senior author. A combined Knee Society Clinical rating score (producing a maximum score of 200) was prospectively collected prior to surgery and post-operatively at three and six months and one, two, five and 10 years thereafter. Fluoroscopically controlled interface images were obtained from the first 161 knees immediately and again at two years post-operatively to evaluate the progression of osseointergration.

Results: One thousand two hundred and thirty-five patients (M:F; 605:630) with a mean age of 67 years (range 34–97 years) underwent TKR mainly for osteoarthritis (94%) and inflammatory arthropathies (3%). Mean follow-up was 78 months (range 20–145 months). There were 720 unilateral and 1030 bilateral replacements (824 simultaneous, 206 staged) with 1750 replacements in total. Mean pre-operative knee score was 97 with a range of movement (ROM) from seven to 114 degrees. At five and 10 years, scores were 182 and 178 with a ROM of one to 114 and zero to 112 degrees respectively. Sixty-one (4.9%) patients have died since surgery including two peri-operative deaths for MI. There have been 12 (0.7%) cases requiring revision, primarily for septic loosening (six cases). There have been 16 deep infections (0.9%), 29 proven pulmonary emboli (1.7%) and five periprosthetic fractures (0.3%). There has been one (0.06%) case of aseptic loosening requiring revision.

Conclusion: These results reveal with an adequately designed prosthesis the use of hydroxyapatite in TKR produces reliable osseointergration that is comparable to other methods of fixation as demonstrated with minimal revision rate and incidence of loosening. The clinical results produce excellent ROM with good medical and functional outcomes in the long term.

Introduction The decision to perform bilateral total knee replacement (TKR) either simultaneously or as a staged procedure is made depending on the level of disease severity, comorbidities, total anaesthetic time and cost. We compared the outcomes of these two bilateral groups of patients with unilateral TKR.

Methods Between August 1992 and December 2002 all patients requiring primary TKR received an uncemented, hydroxyapatite-coated, posterior cruciate ligament retaining prosthesis implanted by the senior author. All peri-operative complications were recorded prospectively, as were pre-operative and post-operative knee scores (Knee Society Clinical Rating Score) at three and six months, and one, two, five, and 10 years thereafter. Patients were divided into three groups being; simultaneous bilateral TKR (SIM), staged bilateral TKR (STA), and unilateral TKR (SIN) with the outcomes of each group compared for statistical significance. One thousand one hundred and forty patients (1638 knees) were included in the study. The majority of patients were female in the STA and SIN groups (60% and 53% respectively) and males in the SIM group (57%). There were 790 (SIM), 206 (STA), and 642 (SIN) knees with mean ages of 67 (SIM), 65 (STA), and 67 years (SIN). The primary diagnosis was OA in each of the groups (> 93%).

Results Pre-operative and post-operative scores revealed no significant differences (p> .05) between the groups. Mean scores ranged from 94 to 98 pre-operatively and increased up to 182 to 187 at five years. Post-operative complications were significantly higher (p< .01) in both bilateral groups. There were 68 (17.2%) and 16 (15.5%) cases of thrombi in the SIM and STA groups respectively compared to 60 (9.3%) cases in the SIN group. Pulmonary emboli were also significantly higher in the bilateral groups compared to the unilateral group (p< .01). The rate of deep infection was higher (p=.09) in the STA group compared to the SIM and SIN groups (2.9% of patients compared to 1.1% and 1.4% respectively). There have been 10 revisions (four SIM, one STA, and five SIN) and two cases of peri-operative death (one STA, one SIM) both due to MI.

Conclusions While simultaneous TKR has higher rates of post-operative complication compared to unilateral TKR, it is less than staged TKR. Therefore simultaneous bilateral knee replacements, when indicated, are the ideal treatment of choice compared to staged procedures.

Although hydroxyapatite (HA) coating is known to enhance fixation in THR, its role in the fixation of Total Knee Replacements is less well appreciated. This study was performed to assess the medium-term results of an HA-coated TKR.

Between August 1992 and 1998 all patients requiring a primary TKR were treated with a hydroxyapatite-coated, PCL-retaining prosthesis implanted by the senior author. The HA coating used was 70 microns thick with 75% crystallinity and 20% porosity. It is deposited on a beaded heat-sintered surface. A combined Hospital for Special Surgery and Knee Society Score was recorded pre-operatively and at three, six, 12, 24 and 60 months post-operatively. Fluoroscopically-controlled interface views were performed on the first 161 knees immediately post-operatively and repeated 24 months postoperatively.

Six hundred and ninety two patients (Male:Female 335:357) with a mean age of 68 years (31–88 years) underwent 1 000 TKR mainly for OA (93%) and inflammatory arthropathies (RA 3%, psoriasis 1%). The mean follow up was 75 months (40–115). There were 461 unilateral (R:L 256:205) and 539 bilateral replacements (462 simultaneous and 77 staged).

The pre-operative knee score was 95/200, ROM 6–115 degrees and at latest review was 182/200, ROM 1–113 degrees.

Forty four patients have died (mean age 73 years, range 54 to 88). There have been 14 deep infections (1.4%), 22 proven pulmonary emboli (2.2%) and five periprosthetic fractures (0.5%). Six revisions have been performed. Visible gaps between bone and implant were present in 91% of femora and 58% of tibiae initially and in 6% of femora and 8% of tibiae at two years on interface views. There have been no cases of clinical loosening.

Currently, this study comprises the largest known series of HA-coated total knee replacements. These results demonstrate that HA appears to enhance fixation of uncemented knee prostheses which maintain good clinical outcomes.

Arthrofibrosis following ACL reconstruction prevents the patient from regaining full knee movement postoperatively.

Our aim was to determine whether acute reconstruction (performed within 3 weeks of injury) is associated with an increased risk of arthrofibrosis compared with chronic reconstruction (performed more than 8 weeks after injury).

We performed a prospective study of 114 patients who underwent a patellar tendon ACL reconstruction: 62 patients underwent acute reconstruction and 52 patients underwent chronic reconstruction. All patients were operated on by a single surgeon using a standardised arthroscopic technique and accelerated rehabilitation programme. All patients were assessed independently by an experienced physiotherapist at an average of 7 months post-operatively. Range of motion, stability, muscle strength and functional scores were measured.

There was no significant difference in the incidence of arthrofibrosis between the acute and chronic groups. Flexion of less than 125° or a loss of extension of more than 10° occurred in 8 (12.9%) of the acute group and in 9 (17.3%) of the chronic group.

All knees were clinically stable, but the mean KT1000 difference was 1.21mm in the acute group and 1.89mm in the chronic group (p< 0.05). There were no significant differences in muscle strength or functional scores between the two groups.

There were significantly more meniscal injuries (65% versus 31%) and chondral lesions (31% versus 18%) in the chronic group.

Acute ACL reconstruction is not associated with an increased risk of arthrofibrosis. However, it is associated with increased stability and less meniscal and chondral pathology. This study suggests that the optimum time for ACL reconstruction is within the first 3 weeks after injury.

The purpose of this study was to assess whether there was significant variation in distal femoral morphology between individuals. In the first part of this study we analysed the distal femoral morphology of 100 consecutive patients undergoing routine total knee replacement for osteoarthritis. In the second part we reviewed the morphology of 50 cadaveric distal femoral specimens without osteoarthritis. There was considerable variability in distal femoral morphology.

Our findings suggest that: 1, use of the posterior condylar axis for femoral component alignment should be used cautiously; 2, problems in balancing flexion and extension gaps on both sides of the knee can be predicted; 3, a greater range of femoral component shapes should be available.

Introduction: The Motus (Osteo) total knee replacement design is an uncemented, stemless, hydroxyapatite-coated prosthesis designed as a low profile resurfacing implant.

Aim: To review the results after five to eight years of the use of this prosthesis by one surgeon and to discuss the perceived advantages of its design.

Methods: Between 1992 and 1996 the Motus (Osteo) prosthesis was used in 606 primary total knee replacements in 409 patients. The evaluation was undertaken using a clinical knee score based on the Knee Society Score and the Hospital for Special Surgery (HSS) score, which produces a maximum score of 200/200.

Results: The mean age was 69 years (range: 31 to 88 years) with 53% of the patients being female. Osteoarthritis was the underlying pathology in the majority of the cases. The minimum time to follow up was 60 months (mean: 79, range: 60 to 104 months). The mean pre-operative knee score was 98/200 with a range of movement from six degrees to 122 degrees. After five years, the mean knee score was 180/200 with a range of movement from one degree to 113 degrees. To date only two patients have required a revision procedure, both for deep infection. Twenty-six patients have died and six have been lost to follow-up as they are overseas.

Conclusion: At a minimum five-year review, the Motus (Osteo) total knee replacement prosthesis produced excellent functional and clinical results with a low rate of complications.

Introduction: Dysfunction of the patellofemoral mechanism presents as patella dislocation or subluxation with or without anterior knee pain. Causes are numerous and include ligamentous deficiency, muscular deficiency, anomlies of bony alignment and patellofemoral joint abnormalities. The 130 different procedures described to treat this condition reflect the multiple pathologies responsible. No single procedure has gained widespread acceptance. We present a surgical technique that attempts to correct as many of these deficiencies of the patellofemoral mechanism as possible.

Method: The procedure consists of a lateral release, a vastus medialis tendon advancement and a tibial tubercle osteotomy. The ‘Q’ angle is corrected by medialisation of the tubercle, patella alta is corrected by a distalisation technique and joint reaction forces through the patellofemoral joint are reduced by placing the tibial tuberosity in a more anterior position.

100 patients who have undergone this procedure have been identified. 81 percent initially presented with patella subluxation or dislocation. The remainder complained of anterior knee pain with evidence of abnormal patella tracking on examination. 52 percent of our patients had undergone at least one previous patellofemoral realignment procedure which had failed. 43 percent of the patients had generalised ligamentous laxity.

Results: The mean follow-up was 2.6 years from the index operation. 81 percent of the patients stated the operation had improved or abolished their symptoms. Generalised ligamentous laxity was present in the remaining 19 percent and seemed to correlate with a poor outcome. 66 percent of patients stated they were satisfied with the outcome of the surgery. Two patients developed recurrent subluxation after surgery and one of these has undergone a revision distal realignment procedure.

Using the functional category described by Crosby and Insall for patellofemoral symptoms 66 percent had a good-to-excellent outcome, 23 percent had a fair outcome and 10 percent of the patients stated they were worse following the procedure with increased anterior knee pain. 100 percent of these patients had grade 3 or 4 cartilage defects on retropatella surface. 57% of patients returned to sporting activity. 14% of the remainder had not returned to sporting activity because of persisting symptoms in the knee.

57 percent of patients had lost a mean 12.5 degrees of flexion of the knee at follow-up [range 5–30]. 5 percent of patients developed minor complications following surgery. No radiological deterioration was seen in any patients although coexistent patellofemoral osteoarthritis was seen in 25 percent of patients. There was no loss of fixation in any of the patients.

Discussion: A multifaceted approach to the complex problem of patellofemoral dysfunction appears to achieve satisfactory functional results in patients even when previous surgical realignment has failed. The procedure appears to be associated with low morbidity although a loss of flexion of the knee is to be expected. Generalised ligamentous laxity and cartilage defects on the retropatella surface appear to be associated with poor results and anterior knee pain in the absence of instability may be a cause for persisting symptoms.

We report four patients with a mean age of 17 years (14 to 22) with external rotation injuries of the knee in slight flexion. Radiographs showed a small fragment in the area of the lateral femoral condyle. At operation, the fragment, consisting of the femoral insertion of the popliteus, was anatomically reduced and fixed. At a mean follow-up of 35 months all the knees had an excellent function score. An isolated lesion of the popliteus often presents as a tendon avulsion whereas major damage to the posterolateral corner of the knee involves combined ligamentous injuries. In patients with an acute haemarthrosis and lateral pain in a stable knee, the diagnosis of isolated avulsion of the popliteus tendon should be suspected. Arthroscopy with special attention to the lateral gutter is indicated. We advise anatomical reduction and fixation of the fragment to prevent possible long-term effects on other posterolateral structures.

We report three cases of avulsion of the ischial tuberosity with marked chronic disability after delay in diagnosis and non-union of the fracture. All were treated by open reduction and internal fixation with return to full function, allowing in one case, athletic performances of Olympic standard. We also report one patient with an acute apophyseal avulsion treated by early reduction and internal fixation with restoration of full function.