Revision arthroplasty with rotating hinge systems for total knee arthroplasty instability.

OBJECTIVE Restoring stability after total knee arthroplasty (TKA) and improving joint function using a cemented rotating hinge system. INDICATIONS Ligament instability and/or osseous defects (including Anderson Orthopaedic Research Institute [AORI] classification type II defects) after primary TKA or TKA revision surgery. CONTRAINDICATIONS Distal femoral or proximal tibial bowing requiring implant systems that provide femoral or tibial offset stems. Persistent periprosthetic infection. Poor therapeutic compliance. AORI type III defects. SURGICAL TECHNIQUE Medial arthrotomy. Femoral and tibial component removal with small saw blades and chisels. Intramedullary alignment for the tibial and femoral cuts. Debridement and removal of membranes and cement remnants. Reconstruction of joint line and correct TKA alignment. Trial reduction. Cement fixation. POSTOPERATIVE MANAGEMENT Unrestricted range of motion, partial weight bearing for 4 weeks. RESULTS Between 2012 and 2013, 18 patients suffering from ligament insufficiency after TKA were revised using the described system and included in a prospective study protocol. The mean follow-up was 37 months (range 30-46 months). There was a significant improvement of the Oxford Knee Score (OKS) from 19 (range 7-29) preoperatively to 29 (range 10-45) postoperatively (p = 0.004). The Knee Society Score (KSS) knee assessment subscore improved from 35 (range 9-70) to 67 (range 35-97) (p = 0.002) and the pain score from 7 (range 0-50) to 24 (range 0-50) (p = 0.008).