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Seven cases of total knee arthroplasty (TKA) after formal knee fusion were reviewed at a mean follow-up of 56 months (range, 12-161 months). The mean modified Hospital for Special Surgery score improved from 54 (range, 16-65) preoperatively to 68 (range, 57-80) at the latest follow-up. Mean range of motion was 74 degrees (range, 55-90 degrees ). Patient subjective rating was excellent or satisfied in 5 of 7 cases. Two patients underwent secondary refusion (1 for chronic infection, 1 for ligamentous instability). Six patients (86%) had to undergo reoperation for postoperative complications: 3 patients had open arthrolysis for adhesion and arthrofibrosis, 2 patients had a gastrocnemius flap for skin necrosis, and 1 patient had neurolysis of the peroneal nerve for painful paresis. Despite the presence of increased postoperative pain while walking, all 5 patients with the TKA still in place declared that they would undergo the same procedure again. The procedure of TKA in fused knees is technically demanding and has a considerable complication rate. Renewed mobility of the fused knee joint appears to correlate with increased pain on walking in this group of patients. Four types of postoperative problems were noted in the evaluation: skin necrosis, extensor mechanism contracture, insufficient collateral ligaments, and adhesion and arthrofibrosis. Takedown of a formal knee fusion with TKA should be performed only in carefully selected cases and in highly motivated patients with realistic expectations.

The Zweymüller shaft for uncemented total hip arthroplasty was developed in the early 1970s. Encouraged by the clinical results with this stem, which was mainly used in primary arthroplasty, longer fitting stems were added to the line to accommodate bony defects and to allow for an optimal load transfer from proximal to distal. The principal of the design is to allow an optimal distal fixation while allowing the bone to remodel in the proximal part. This study reports on 89 patients who underwent revision surgery of the hip for mostly aseptic loosening. The results after a median follow-up of 36 months show an increase of the modified Harris hip score from 52 points pre- to 82 points postoperatively. Radiographic subsidence was found in nine cases, with eight having progressed for more then 3 mm. Postoperative complications occurred in 11.2%, with seven dislocations. Open revision became necessary in two cases. The stem reviewed here seems to achieve predictable results in cases where a proximal cone is still present to facilitate load transfer, while at the same time the quadrangular stem provides solid distal fixation and ensures rotary stability.

The correct therapy of osteochondritis dissecans in patients under 16 years is very important to prevent the knee joint from secondary arthritis. We analysed clinical, radiological and with MRI the long term (10 years) results of a follow-up study on 36 patients under 16 years with 42 operatively treated osteochondritis dissecans of the knee joint. There were excellent and good results in 81% of the patients. After an average of 10 years there were no signs of arthritis which would necessitate any treatment.