[Balancing of soft tissues in total knee arthroplasty for patients with rheumatoid arthritis with knee flexion contracture].

OBJECTIVE: To explore the technique of the soft tissue balancing in the total knee arthroplasty (TKA) for the patients of rheumatoid arthritis with flexion contracture.

METHODS: From November 1997 to May 2006, 38 patients with rheumatoid arthritis with flexion contracture underwent primary bilateral TKA and balancing of the soft tissues, among whom there were 8 males and 30 females, aged 48-71 years old (58.2 on average). The course of disease was 28 months-16 years (7.6 years on average). The preoperative flexion contracture was (38.2 +/- 11.3) degrees. The average range of motion (ROM) and HSS score were (49.1 +/- 17.8) degrees and 23.9 +/- 16.9, respectively. According to the preoperative flexion-contracture degree of the knees, these patients were divided into 3 levels: 5 patients with < or = 20 degrees, 26 patients with 20-60 degrees and 7 patients with > or = 60 degrees. During the TKA procedure, based on the correct osteotomy, different methods of soft tissue balancing were used for different degrees of flexion contracture. The TKA soft tissue treatment was summed up as the releasing of posterior structures and the balancing between medial collateral ligaments (MCL) and lateral collateral ligaments (LCL), etc.

RESULTS: The flexion contractures in 38 cases were all improved after the operation, among which 33 patients had a complete correction and only 5 patients had a residual flexion contracture of 5-10 degrees. Eight knees suffered from complications within 1 week after operation, among which 3 had subcutaneous superficial infection and 5 had deep vein thrombus (DVT). These patients obtained good healing after active treatment. All the 38 patients were followed up for 10 months to 8 years with the median time of 37 months. The postoperative flexion deformity declined to (2.4 +/- 5.7) degrees, and the ROM and HSS scores were (96.3 +/- 14.6) degrees and 81.7 +/- 10.4, respectively. There was statistical difference (P < 0.05). According to the HSS score, 27 patients (71.05%) were rated as excellent, 6 good (15.79%) and 5 fair (13.16%), and the choiceness rate was 86.84%.

CONCLUSION: The balancing of the soft tissue is a major treatment for correction of the flexion contracture, which can avoid bone over-resection during the surgery of TKA. The proper balancing of the soft tissue can not only achieve an obvious correction of the flexion contracture but also effectively improve the range of motion and the functional recovery of the knee joint after TKA.