We evaluated the midterm results of total knee arthroplasty in degenerative knee joint diseases with severe deformity.
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).
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 .
Total knee arthroplasty performed in degenerative knee joint diseases with severe deformity significantly improves patients' complaints and functional results.