[Midterm results of total knee arthroplasty in degenerative knee joint diseases with severe deformity].

OBJECTIVES: We evaluated the midterm results of total knee arthroplasty in degenerative knee joint diseases with severe deformity.

METHODS: Total knee arthroplasty was performed in 125 knees of 86 patients (75 women, 11 men; mean age 69 years; range 39 to 85 years) with degenerative knee joint diseases accompanied by severe deformity. Almost all the patients had osteoarthritis (100 knees, 80%) or rheumatoid arthritis (22 knees, 17.6%). Thirty-nine patients with bilateral involvement underwent single-stage (n=20) or two-stage (n=19) surgery. During surgery, the posterior cruciate ligament was sacrificed in 108 knees and retained in 17 knees. Pre- and postoperative assessments were made according to the Knee Society clinical scoring system. The mean follow-up was 53 months (range 24 to 96 months).

RESULTS: The results were excellent or good in 80.2% of the knees. Nine knees (7.2%) required revision surgery, of which preoperative diagnosis was rheumatoid arthritis in five. The reasons for revision were infection-related problems (n=5), aseptic loosening (n=3), and periprosthetic fracture (n=1). Compared with preoperative values, the mean knee score increased by 60.9 (from 26.2 to 87.1), and the mean functional score increased by 42.6 (from 33.2 to 75.8) (p<0.05), with a mean range of knee joint motion of 93.2 degrees . The mean preoperative and postoperative alignments were 17.8 degrees of varus and 4.1 degrees of valgus (range 0 degrees to 6 degrees ), respectively. The number of knees with a flexion contracture decreased from 68 (mean 28.8 degrees ) to 8 (mean 8.4 degrees ), all of which had a flexion contracture angle below 10 degrees .

CONCLUSION: Total knee arthroplasty performed in degenerative knee joint diseases with severe deformity significantly improves patients' complaints and functional results.