[Impact of Preoperative Knee Stiffness on the Postoperative Outcome after Total Knee Arthroplasty in Patients with Haemophilia]. / Einfluss der präoperativen Kniesteife auf das postoperative Ergebnis nach Knieendoprothetik bei Patienten mit Hämophilie.

INTRODUCTION: Total knee arthroplasty (TKA) is an effective treatment option for patients with end-stage haemophilic arthropathy of the knee. However, the procedure is technically challenging, as knee motion is often restricted before the operation and complication rates are then thought to be higher than for patients with a normal range of motion (ROM). There is very limited information on the outcome of TKA in haemophilic patients presenting with stiff knees. The objective of the present study was to retrospectively analyse and compare the clinical results after TKA in haemophiliacs with stiff and non-stiff knees. PATIENTS AND METHODS: The results of 50 TKA procedures in 41 haemophilic patients were retrospectively evaluated at a mean follow-up of 7.2 ± 4.9 years (range 2-25 years). 20 patients presenting with 23 stiff knees - defined by a preoperative ROM of 50° or less - were compared with 21 patients with 27 non-stiff knees. Knee motion (ROM, flexion, extension), Knee Society Score (KSS/KSS function), pain status (visual analogue scale, VAS), number of bleedings and patient satisfaction were evaluated. RESULTS: The complication rate was 12 %, including two haematomas, one aseptic loosening, and three periprosthetic infections. The overall mean ROM increased from 58.6 ± 34.2° (range 0-120°) preoperatively to 85.9 ± 23.4 (35-130°) postoperatively (p < 0.005). Mean KSS and KSS function improved from 30.6 ± 11.0 points (range 10-49) and 43.4 ± 9.3 points (range 15-65) to 79.3 ± 9.6 points (range 49-95) and 68.9 ± 11.0 points (45-90), respectively (p < 0.005). The mean VAS score decreased significantly from 7.9 ± 0.8 points (range 6-9) to 1.8 ± 1.1 points (range 0-4; p < 0.005). In comparison to the non-stiff group, patients with stiff knees showed a significantly greater mean improvement in ROM (46.3 ± 21.8° [range - 10-85°] vs. 9.4 ± 16.9° [range - 30-35°]), flexion (32.8 ± 19.6° [range - 10-85°] vs. 5.2 ± 16.2° [range - 40-35°]), and flexion contracture (13.5 ± 9.6° [range 5-30°] vs. 5.9 ± 6.7° [range 5-20°]). Both KSS and KSS function were significantly inferior in stiff knees than with non-stiff knees. Nine patients with knee stiffness who underwent additional v-y quadricepsplasty to lengthen the extensor mechanism developed a mean extensor lag of 7-0° ± 4-8° (range 5-15°). At final follow-up, 37/41 patients were satisfied or very satisfied with the surgical result. CONCLUSION: TKA in haemophilic patients presenting with haemophilic arthropathy of the knee results in significant improvements in function and reduced pain. Although the ultimate clinical outcome in stiff knees is inferior to that with non-stiff knees, joint replacement surgery can be successfully performed in patients with restricted preoperative range of motion. Vy-quadricepsplasty for to facilitate exposure is associated with the development of a postoperative extensor lag and should therefore be performed restrictively. Patient satisfaction after TKA was equally high in the two groups.