Introduction

The purpose of this study was to determine whether the patient's perceived outcome and speed of recovery differs between a posterior cruciate ligament (PCL) substituting (cam-post type) and PCL sacrificing (ultracongruent polyethylene) total knee arthroplasty (TKA).

The posterior-stabilized knee prosthesis is designed specifically to provide the posterior stability to a knee arthroplasty when PCL is deficient or has to be sacrificed. Posterior dislocation of such prosthesis is rare but dreaded complication. There are several causes of postoperative dislocation such as malposition of the prosthesis, preoperative valgus deformity, a defect of the extensor mechanism and overwidening of the flexion gap. Posterior-stabilized rotating-platform mobile-bearing knee implants have been widely used to further improve the postoperative range of motion by incorporation of the post and cam mechanism to improve the posterior roll back during flexion and to overcome the wear and osteolysis problems due to significant undersurface micromotion of posterior-stabilized fixed-bearing knees. But, spin-out or rotatory dislocation of the polyethylene insert can occurs as result of excessive rotation of the rotating platform accompanied by translation of the femur on the tibia after mobile-bearing total knee arthroplasty, but that is very rare. Here, authors describe an unusual case of acute 180° rotatory dislocation of the rotating platform after posterior dislocation of a posterior-stabilized mobile-bearing total knee arthroplasty.

A 71-year-old male with knee osteoarthritis underwent a TKRA using posterior-stabilized mobile-bearing prosthesis. The posterior dislocation of the total knee arthroplasty occurred 5 weeks postoperatively(Fig. 1). We underwent closed reduction of posterior dislocated total knee arthroplasty resulting in a complete 180° rotatory dislocation of the rotating platform (Fig. 2). He was treated with open exploration and polyethylene exchange with a larger component.

This case illustrates that dislocation of a posterior-stabilized mobile-bearing total knee arthroplasty can occur with valgus laxity, cause 90° spin-out of the polyethylene insert and closed reduction attempts may contribute to complete 180° rotatory dislocation of the rotating platform. Special attention needs to be paid to both AP and lateral view to ensure that the platform is truly reduced and not just rotated 180° as was in this case.

The long-term outcome and survivorship of TKA in Asian countries have been reported to be excellent, comparable to Western countries. However, increased knee flexion is required for many daily activities in Asian cultures, which remains a major problem to be resolved. High-flexion TKA designs have been introduced to improve flexion after TKA and to allow a high degree of flexion in a safe manner. However, several biomechanical studies have shown that high-flexion designs have a greater risk for the loosening of the femoral component compared to the conventional TKA designs. We evaluated the implant survival and the mid-term clinical and radiological outcomes of Asian patients who had undergone high-flexion TKA and assessed whether high-flexion activities increased the risk of premature failure.

We prospectively followed 72 Nexgen LPS-flex fixed TKA in 47 patients implanted by a single surgeon between March 2003 and September 2004. Five patients (6 knees) expired during follow-up. A Kaplan-Meier survivorship analysis using revision surgery as the end point was used to determine the probability of survival for the cohort and the equality of survival between two subgroups who could perform high-flexion activities or not. Median follow-up was 6.5 (0.9–8.6) years.

Twenty-five patients (33 knees) received a revision for aseptic loosening of the femoral component at a mean of 3.5 years (range, 0.9–7.8 years). According to the Kaplan-Meier survivorship analysis, the probabilities of survival without revision for aseptic loosening are 66.7% and 51.8% at 5 and 8 years, respectively. The 8-year cumulative survivorship is lower (30.6%) when squatting, kneeling, or sitting cross-legged could be achieved than if none of these activities were possible (78.3%). In the surviving knees, non-progressive radiolucent lines were observed around the femoral component of 12 patients (15 knees) and one tibial component.

The overall mid-term high-flex implant survival of our Asian cohort is lower than that of the conventional and other high-flexion designs. This unacceptable high rate of femoral component loosening is strongly associated with postoperative high flexion activities.

The purpose of this study was to validate the usefulness of SPECT/CT as an evaluation method for determining treatment and prognosis for patellofemoral cartilage lesions, based on MRI and arthroscopic findings.

From August 2009 to February 2010, SPECT/CT was performed on 80 patients (24 male and 56 female, average 53.3 years old) with chronic anterior knee pain who had no degenerative changes or patellar malalignment on plain radiographs. Radioisotope uptake findings on patellofemoral joint from SPECT/CT were classified into three grades by one nuclear medicine specialist. In the patients who demonstrated poor improvements after conservative treatments, MRI and arthroscopy were performed. Patellofemoral cartilage conditions under arthroscopic finding (ICRS grades) were compared with SPECT/CT grading.

In all cases, there were increased uptakes on patellofemoral joints. Eighteen cases showed low uptake (Group 1), 22 cases showed medium uptake (Group 2) and 40 cases high uptake (Group 3). At the follow-up examination after mean 1.7 months, 16 cases of Group 1 (89%), 14 cases of Group 2 (64%) and 28 cases of Groups3 (70%) responded positively to the conservative treatments. For those 22 cases showing poor improvement, MRI and arthroscopy were done. Damage or thinning of patellofemoral cartilage, subchondral cyst, edema and fissuring were observed in every case that underwent MRI. Every arthroscopic case was found that there was patellofemoral cartilage damage. Each of ICRS grade I and grade II was found in 2 cases from Group 1. Two cases of grade II, 4 cases of grade III, and 2 cases of grade IV were found in Group 2. Two cases of grade II, 4 cases of grade III, and 6 cases of grade IV were found in Group 3. There was significant difference in the success rate of conservative treatment between SPECT/CT grade 1 and 2 or 3. And there was significant association between SPECT/CT grade and ICRS grade (P=0.034).

SPECT/CT could be a useful modality in determining the treatment and prognosis for patellofemoral cartilage lesions compared with MRI and arthroscopic findings.

Background: The treatment of congenital vertical talus has traditionally consisted of manipulation and application of casts followed by extensive soft-tissue releases. However, this treatment is often followed by severe stiffness of the foot and other complications. The purpose of this study was to evaluate a new method of manipulation and cast immobilization, based on principles used by Dobbs et al in patients with idiopathic congenital vertical talus, but applied in teratologic congenital vertical talus.

Methods: Five consecutive cases of teratologic congenital vertical talus deformity were prospectively followed at a minimum of nine months post treatment with serial casting and limited surgery consisting of percutaneous Achilles tenotomy, fractional lengthening of the anterior tibial tendon, and percutaneous pin fixation of the talonavicular joint. The principles of manipulation and application of the plaster casts were similar to those used by Ponseti to correct a clubfoot deformity, but the forces were applied in the opposite direction. Clinical and radiographic assessments were carried out at the initial, immediate postoperative and the latest follow-up.

Results: Initial correction was obtained both clinically and radiographically in all five feet. A mean of eight casts was required for correction. At the final evaluation, the mean ankle dorsiflexion was 20° and the mean plantar flexion was 31°. Radiographically, dorsal subluxation of the navicular recurred in one patient, but was functionally insignificant as the patient was a non-ambulator and required treatment for seating purposes only. At the time of the latest follow-up, there was a significant improvement in all of the measured radiographic parameters compared with the pretreatment values.

Conclusions: Serial manipulation and cast immobilization followed by talonavicular pin fixation and percutaneous tenotomy of the Achilles tendon provides excellent results, in terms of the clinical appearance of the foot, and deformity correction, in patients with teratologic congenital vertical talus.

Materials and Methods: The institution’s prospective database of unicompartmental knee replacements was reviewed for all Oxford Phase III Unicompartmental Knee Replacement (Biomet, UK) undertaken from January 2004 to July 2007. This identified a total of 645 procedures undertaken. We included all cases where there was pre-operative skyline radiographs and American Knee Scores, Oxford Knee Score and SF-12 data, in addition to skyline radiographs, OKS and SF-12 data with a minimum of 2 years follow-up. All patients without this baseline and follow-up data were excluded. This provided a total of 196 knees (162 patients)

Using Altman’s nomogram, the sample size was calculated to be 85 for a power of 90%, with an α significance level of 0.05.

Using this database, digital radiographs were assessed using the institution’s PACS system. Pre-operative and follow-up skyline radiographs following Jones et al’s (1993) patellofemoral scoring system were examined by four assessors utilising Jones’ patellofemoral scoring system. In addition, in cases where patellofemoral joint changes were evident, each assessor acknowledged whether this involved the medial, lateral or bilateral aspects of the patellofemoral joint.

Intra-observer reliability was made comparing the four assessors.

Statistical analysis was performed, using the Statistical Package for the Social Sciences (SPSS) 16.0 for Windows (SPSS Inc, Chicago, Illinois).

In order to determine whether changes in patellofemoral joint status related to patients function or quality of life, the difference in OKS and SF-12 from pre-operative to the follow-up period was assessed.

Results: There was a statistically significant progression of patellofemoral osteoarthritis as found on the preoperative and postoperative radiographs (p< 0.01, Mann Whitney), there was a correlation between a low OKS and Jones patellofemoral score (P< 0.05, Mann-Whitney). However, there was no correlation between the site of patellofemoral involvement and outcome scores.

Conclusion: Due consideration should be taken when offering medial unicompartmental knee replacement to patients with patellofemoral involvement and this is independent of the site of patellofemoral involvement.

There has been debate about the role of unicompartmental knee replacement in the presence of radiologically identifiable degenerative changes of the patellofemoral joint. We studied 195 knees in 163 patients in whom an Oxford unicompartmental knee replacement had been performed for medial osteoarthritis between January 2004 and July 2007. The mean age of the patients was 66 years (51 to 93). The degree of degenerative change of the patellofemoral joint was assessed using Jones’ criteria. Functional outcome was assessed at a mean of 3.4 years (2 to 7) post-operatively, using the Oxford knee score and the Short-form 12 score.

Degenerative changes of the patellofemoral joint were seen pre-operatively in 125 knees (64%) on the skyline radiographs. There was no statistically significant difference in the Oxford knee or Short-form 12 scores between those patients who had patellofemoral osteoarthritis pre-operatively and those who did not (p = 0.22 and 0.54, respectively).

These results support the opinion expressed at the designer’s hospital that degenerative changes of the patellofemoral joint in isolation should not be considered to be a contraindication to medial Oxford unicompartmental knee replacement.

We present the results of 90 consecutive children with displaced fractures of the forearm treated by elastic stable intramedullary nailing with a mean follow-up of 6.6 months (2.0 to 17.6). Eight (9%) had open fractures and 77 (86%) had sustained a fracture of both bones. The operations were performed by orthopaedic trainees in 78 patients (86%). All fractures healed at a mean of 2.9 months (1.1 to 8.7). There was one case of delayed union of an ulnar fracture. An excellent or good functional outcome was achieved in 76 patients (84%). There was no statistical difference detected when the grade of operating surgeon, age of the patient and the diaphyseal level of the fracture were correlated with the outcome. A limited open reduction was required in 40 fractures (44%).

Complications included seven cases of problematic wounds, two transient palsies of the superficial radial nerve and one case each of malunion and a post-operative compartment syndrome. At final follow-up, all children were pain-free and without limitation of sport and play activities.

Our findings indicate that the functional outcome following paediatric fractures of the forearm treated by elastic stable intramedullary nailing is good, without the need for anatomical restoration of the radial bow.

Introduction To acquire high flexion has been a current topic in TKA. However, there is concern about the trade-off between high flexion and safety. The purpose of this study was to determine the factors contributing to the high rate of aseptic loosening in femoral components of LPS-flex TKAs that we experienced.

Materials and Methods: From March 2003 to September 2004, 72 consecutive TKA were performed in 47 osteoarthritic patients by a single surgeon. The high-flex design fixed total knee prostheses (NexGen LPS-Flex) were used in all knees. The weight-bearing high flexion activities such as squatting were permitted as tolerable. We retrospectively analyzed the clinical and radiological outcome of this case series.

Results: At a mean of 32 months (range, 30 to 48 months), 27 (38%) cases had shown the radiological findings of aseptic loosening around the femoral components and fifteen (21%) cases have been revised for the progression of component loosening and pain. Postoperatively, the average maximal flexion was 136º in the loosening group, which was higher than 125º in the no-loosening group (P=0.022). The percentage of patients who could squat, kneel or sit cross-legged postoperatively was greater in the loosening group (85% versus 44%) (P=0.001). The femoral component demonstrated movement into flexion, from a mean of 4° to a mean of 7° (γ angle) in the loosening group and not in the no-loosening group.

Conclusion: The high-flex implant allowed for greater range of motion and high-flexion activities, and however, showed high rate of early femoral component loosening, which was associated with weight-bearing high-flexion activities.

Primary total knee arthroplasty is associated with considerable blood loss, and allergenic blood transfusions are frequently necessary. Because of the cost and risks of allogenic blood transfusions, the autologous drainage blood reinfusion technique has been developed as an alternative. A number of studies have compared reinfusion techniques with standard suction drainage, but few reports compared with no drain use. We analyzed early results after primary total knee arthroplasty using autologous drainage blood reinfusion and no drain.

We selected 30 patients who underwent primary total knee arthroplasty using no drain between November 2005 and March 2006 and matched for age and gender with 30 patients who underwent primary total knee arthroplasty using autologous drainage blood reinfusion technique between January 2003 and October 2005. All operations were done under pneumatic tourniquet and meticulous hemostasis was performed after deflation of the tourniquet. We have retrospectively reviewed the preoperative data (age, gender, body mass index, diagnosis, history of the knee surgery, infection and anticoagulant therapy, and medical cormorbidities) and the postoperative data (hemoglobin, hematocrit and platelet during hospitalization, the amount of allogenic blood transfusion and narcotics, complications, rehabilitation process, and clinical scores).

All preoperative and postoperative variables except the postoperative second and seventh days hemoglobin and 2nd day hematocrit showed no significant differences between two groups. The hemoglobin and hematocrit also showed no significant differences at the postoperative fourteenth day.

The autologous drainage blood reinfusion method in primary total knee arthroplasty does not have significant clinical benefit over no-drain method with regards to allogenic blood transfusions, narcotics uses, the incidence of complications and rehabilitation processes.

‘Tribology’ is derived from the Greek word “tribos” and means the “science of rubbing”. Friction, lubrication, and wear mechanism in the common English language means the precise field of interest of tribology. Wear of PE insert has often been reported in TKA to be primary causes of complications and failure.

As a friction, the wear that occurs in TKA is system properties rather than intrinsic material properties and is therefore affected by multiple variables such as design, material properties, duration and alignment. The contact area on each condyles varies from about 150 mm² for moderate to high-conformity knees in flexion, down to 30 mm² for low-conformity. The corresponding maximum compressive pressure in activity is 10 to 50 MPa, which favor fatigue and deformation of UHMWPE (yield stress: 15MPa). In contrast, fully conforming mobile bearing knees have contact area of at least 300 mm² on each condyles, giving maximum pressure of only 5 MPa. There are several mechanisms whereby small PE particles are released in TKA. Some of these mechanisms are fatigue processes requiring numerous cycles of sliding. Multidirectional sliding is more damaging than sliding in same direction. The wear mechanisms in TKA are as follows:

Adhesive wear

There have been a number of published studies on the in vivo wear measured on retrieved total knee bearings. These studies indicated more clinical wear on the medial side. Patterns of wear varied greatly among individual knees; a majority showed very similar extents of wear on the medial and lateral sides, however there were cases with significantly more wear on one condylar articulation than the other. Evidence of edge loading was common and seen most frequently in the central zone of the medial condylar area.

Wound complication including superficial infection is a concern after total knee arthroplasties (TKA) in diabetics. However, influence of glycoregulation before TKA has not been investigated in relationship to wound healing. Our hypothesis was that glycated hemoglobin (HbA1C), since it reflects long-term regulation of blood glucose, might be associated with incidence of wound complications after TKA in diabetic patients.

We retrospectively reviewed 167 TKAs performed in 115 patients with diabetes mellitus between January 2001 and March 2007. All patients were diagnosed as type II DM and osteoarthritis. A wound complication was defined as a hematoma, bulla, drainage or superficial infection. Stepwise multivariate logistic regression was used to identify which variables had a significant effect on the risk of wound complications. Variables considered were age, gender, body mass index, histories of previous knee surgery, comorbidities, duration of diabetes, the methods of diabetes treatment, complications of diabetes, preoperative HbA1c level, operation time, antibiotics-impregnated cement use, the amount of blood transfusion, and postoperative blood glucose level.

The overall incidence of wound complications was 6.6% (n=11) including superficial infection in 1.8% (n=3), hematoma or bullae in 3.6% (n=6), and drainage in 1.8% (n=3). There were seven cases (4.2%) of deep infection. A multivariate logistic regression revealed that independent risk factors for the development of wound complications were preoperative HbA1C ≥ 8% (odds ratio 6.074, 95% confidence interval 1.119–32.971) and operation time (odds ratio 1.013, 95% confidence interval 1.000–1.026).

Poorly controlled hyperglycemia before surgery may increase the incidence of wound complications among diabetic patients receiving total knee arthroplasties. The correlation of glycemic control and wound complications may assist in the preoperative evaluation and selection of time for surgery.

We performed a systematic review of the optimal management of septic arthritis in children as recommended in the current English literature using MEDLINE, EMBASE, CINAHL, the Cochrane Library and reference lists of retrieved articles without date restrictions up to 31 January 2009. From 2236 citations, 227 relevant full-text articles were screened in detail; 154 papers fulfilled the inclusion criteria, from which conclusions were drawn on the management of infected joints in children.

Our review showed that no single investigation, including joint aspiration, is sufficiently reliable to diagnose conclusively joint infection. The roles of aspiration, arthrotomy and arthroscopy in treatment are not clear cut, and the ideal duration of antibiotic therapy is not yet fully defined. These issues are discussed. Further large-scale, multi-centre studies are needed to delineate the optimal management of paediatric septic arthritis.

We have examined the results obtained with 72 NexGen legacy posterior stabilised-flex fixed total knee replacements in 47 patients implanted by a single surgeon between March 2003 and September 2004.

Aseptic loosening of the femoral component was found in 27 (38%) of the replacements at a mean follow-up of 32 months (30 to 48) and 15 knees (21%) required revision at a mean of 23 months (11 to 45). We compared the radiologically-loose and revised knees with those which had remained well-fixed to identify the factors which had contributed to this high rate of aseptic loosening.

Post-operatively, the mean maximum flexion was 136° (110° to 140°) in the loosened group and 125° (95° to 140°) in the well-fixed group (independent t-test, p = 0.022). Squatting, kneeling, or sitting cross-legged could be achieved by 23 (85%) of the loosened knees, but only 22 (49%) of the well-fixed knees (chi-squared test, p = 0.001). The loosened femoral components were found to migrate into a more flexed position, but no migration was detected in the well-fixed group.

These implants allowed a high degree of flexion, but showed a marked rate of early loosening of the femoral component, which was associated with weight-bearing in maximum flexion.

Introduction and Aims: A significant proportion of patients currently undergoing total knee arthroplasty have uni-compartmental disease. Unicondylar knee replacement (UKA) offers the benefits of less bone resection and better soft tissue retention. However, knee kinematic changes after UKA have not been established.

Method: A significant proportion of patients currently undergoing total knee arthroplasty have uni-compartmental disease. Unicondylar knee replacement (UKA) offers the benefits of less bone resection and better soft tissue retention. However, knee kinematic changes after UKA have not been established.

Results: In the normal knee, knee flexion was accompanied by femoral rollback and tibial internal rotation. Similar patterns of rollback and rotation were seen after UKA. Surprisingly, resecting the ACL did not affect rollback or tibial rotation. However, tibial rotation was significantly different and was more variable after TKA. This suggests that loss of the ACL may not be the major cause of abnormal kinematics after TKA.

Conclusion: Abnormal kinematics have been previously reported after TKA. However, UKA appeared to maintain normal kinematics. This study reported kinematic advantages to UKA, in addition to less bone resection and better recovery.