Jordy van Sambeeck

Twelve year follow-up of a stand-alone lateral condyle elevating trochlear osteotomy 6 91 dislocations were reported in 4 knees (4 patients)(table 2). This rate of patellar instability is higher than reported at two years follow-up at which time only 2 patellar dislocations had occurred, both within the first months postoperatively. On physical examination, no knees showed swelling or effusion. All knees had a full range of motion. A positive apprehension test for patellar dislocation was present in 3 out of 14 knees, a positive J-sign in 7 out of 14 and the Rabot sign was positive in 12 out of 14 knees (Table 3). Radiological evaluation of osteoarthritis in the patellofemoral compartment according to the Iwano classification 21 (Figure 2) is shown in Table 4. According to the K-L scale 20 , assessment of osteoarthritis in the medial tibiofemoral compartment showed no osteoarthritis in 7 out of 15 knees (46.7%) and grade 1 in 8 out of 15 knees (53.4%) and on the lateral side no osteoarthritis in 7, grade 1 in 7 and grade 2 in 1 out of 15 knees (46.7%, 46.7%, and 6.7% respectively). We observed an increase in radiologic osteoarthritis in all 3 compartments when compared to its pre-operative values, but it is limited to the lower grades on both the Iwano and K-L classifications. In addition to these 15 knees, one patient (one knee) was converted to a patellofemoral arthroplasty due to progressive osteoarthritis and pain 3 years after her trochlear osteotomy. No correlation between VAS-pain, Lysholm, WOMAC or Kujala score and either patellofemoral or tibiofemoral osteoarthritis could be identified (Spearman’s correlation coefficient, p-values all ≥ 0.365). Score Pre-operative 2-years follow-up Final follow- up P-value (figures in bold are significant) VAS-pain (range, std dev.) 52.5 (7-95, 30.1) 23.1 (0-60, 17.7) 32.3 (0-66, 28.0) * p=0.003 † p=0.134 ǂ p=0.271 Lysholm 49.5 (27-78, 17.7) 80.9 (54-100, 15.5) 71.8 (35-100, 18.6) * p=0.000 † p=0.021 ǂ p=0.050 WOMAC 73.9 (50-100, 20.5) 89.5 (65-100, 10.7) 91.2 (74-100, 9.1) * p=0.012 † p=0.021 ǂ p=0.618 Kujala Not performed Not performed 75.57 (40-100, 19.0) Not applicable Table 1. Median values for VAS-pain, Kujala, Lysholm and WOMAC scores pre-operative, at 2 years follow-up and at final follow up. Std. dev.= Standard deviation. * Pre-operative to 2 years FU, † Pre-operative to final FU, ǂ 2 years FU to final FU (all repeated- measures ANOVA test)