RESUMEN
Severe metallosis following medial unicompartmental knee arthroplasty (UKA) is relatively rare. It is usually due to long-standing wear of the polyethylene component, resulting in frictional wear between the femoral and tibial metallic components. Biomechanical and cadaveric studies have shown the effects of anterior cruciate ligament (ACL) transection following medial UKA. We describe a case of a 58-year-old male who developed attritional rupture of the ACL 16 months following medial UKA leading on to early accelerated failure over the next 8 months. The patient underwent revision to total knee arthroplasty with good outcome. The clinical effect of spontaneous ACL transection on medial UKA causing abnormal posteromedial wear of polyethylene component and tibial tray, massive metallosis, and worsening of mechanical axis can be demonstrated in this case report.
RESUMEN
BACKGROUND: The presence of extra articular deformities either in the femur or the tibia with arthritis of the knee makes total knee arthroplasty (TKA) technically demanding. The purpose of this study is to report outcomes with Total Knee Arthroplasty in patients with arthritis of the knee associated with extra articular deformity by intraarticular resection and soft tissue balancing. MATERIALS AND METHODS: Thirty six knees (32 patients) who had arthritis of the knee associated with extra articular deformity, underwent total knee arthroplasty between 1999 and 2006 were included in this retrospective analysis. All patients had intraarticular resection with soft tissue balancing to correct the deformity. Full length weight bearing anteroposterior X-rays, Knee society scores, and Knee range of motion was recorded pre- and postoperatively. RESULTS: The mean period of followup was 85 months (range 42-120 months). The deformities amenable to correction by intraarticular resection in our series were Femur- Coronal plane 11°-18° (mean 16.2°) Saggital plane 0°-15° (mean 10.1°) Tibia - Coronal plane 12°-24° (mean 21°). There was an improvement in the range of motion from mean of 54° preoperatively to 114° postoperatively (P value < 0.05). The Knee Society- Knee Score improved from 37 points to 85 points postoperatively (P value < 0.05). The functional score improved from a mean value of 19 to a mean of 69.5 at followup (P < 0.01). The preoperative hip knee ankle angle in the coronal plane improved from a mean of 14° ± 2° varus (26° varus to 4° valgus) to a mean of 2° ± 0.6° varus (6° varus to 2° valgus). CONCLUSION: With a good preoperative planning and templating, intraarticular bone resection and good soft tissue balancing both in flexion and extension, correction would be possible in majority of extraarticular deformities.
RESUMEN
Between December 2002 and December 2007, we retrospectively assessed the mid term results of the Nexgen rotating hinge prosthesis in the hands of a single surgeon in difficult primary and complex revision situations. Forty four patients (46 knees) were included in the study: they were followed for an average of 62 months. Knee Society knee score improved from a preoperative mean value of 47 to a mean value of 81 at follow-up (p < 0.05) whereas the mean function score improved from 17 (0-40) to 67.5 (0-90) at follow-up (p < 001). Mean flexion range improved from 65 degrees to 96 degrees at follow-up (p < 0.05). In conclusion, rotating hinge knees gave satisfactory results in difficult revision situations associated with major bone loss, instability or periprosthetic fracture. They also provided satisfactory results in selected cases of advanced primary osteoarthritis.
