Time-dependent clinical and roentgenographical results of Coventry high tibial valgisation osteotomy

Abstract

We analyzed the time-dependent results after Coventry osteotomy in 118 patients (129 cases) with unicompartmental osteoarthrosis of the knee. The median follow-up was 11.6 years (range 0.7–17 years). Data were noted according to the time since surgery. Group I (> 2 years) consisted of all 129 cases, group II (> 4 years) of 41 cases and group III (> 8 years) of 15 cases. The HSS knee score (mat. 100 points) improved from 33.2 ± 20.4 (range 17–60) to 68.3 ± 25.3 (range 30–90) in group I, to 54.7 ± 18.9 (range 29–90) in group 11 and to 43.7 ± 20.9 (range 23–85) in group III. The improvement started 4.6 ±7.8 months (range 0–60 months) after the operation and persisted for 4 years ± 37.4 months (range 0–125 months). The functional knee score (max. 100 points) changed from 61.7 ± 14.1 (range 41–70) to 71.7 ± 13.1 (range 53–87) in group I, to 70.0 ± 11.8 (range 54–88) in group II and to 64.2 ± 8.0 (range 42–90) in group III. The initial loss in knee flexion was 5.6° (range 0°–20°) and for extension 1.0° (range −5°–-25°). Anteroposterior ligament stability (max. 10 points) decreased from 9.2 ± 2.1 (range 2–10) to 5.6 ± 1.7 (range 2–9) in group III. Lateral ligament stability (max. 15 points) was relatively constant, from 12.6 ± 1.9 (range 4–15) to 9.7 ± 1.9 (range 2–14). Complications included one tibia fracture, one infection, six peroneus pareses, four haematomas and one pseudarthrosis. The mechanical axis was corrected to an average knee valgus of 5.2° ± 7.4°, which deteriorated over time. Radiographic evidence of arthrosis appeared independent of the operation.