Abstract
Introduction: An accepted treatment of lateral compartment osteoarthritis with valgus deformity is to correct the malalignment, and unload the affected compartment. Previous techniques have used large fixation plates to secure complete osteotomy sites. We present a prospective study using a novel incomplete opening wedge osteotomy, in treating lateral compartment osteoarthritis in active patients younger than 65.
Methods: We assessed all patients (n=26) who underwent opening wedge femoral osteotomy with Puddu plate fixation over a 5 – year period by one surgeon (PRA). All patients had long leg X rays and arthroscopic evaluation; revealing either grade 3 and 4 osteoarthritis within the lateral compartment; 11 secondary to lateral menisectomy, 4 to complex trauma to the lateral tibial plateau, the others were diagnosed with primary osteoarthritis. Pre operative and post-operative Knee Society and Oxford Knee scores and long leg X rays were used to monitor subjective and functional improvement.
Results: Patients had a mean age of 48, (mode 56); ASA of 1 (range 1–2); and BMI of 24 (range 20–26). Mean follow up time was 46.8 months (6–62 months). Results in table 1 show early benefits in post-operative pain and improved function scores, which were maintained to 42 months. All patients had radiological union by 3 months (2–8months). Plates were removed as a minor procedure in some patients at 8 months (6–18 months), and did not lead to loss of correction or conversion to total knee replacement within the study.
Subjective and functional progress was observed by using the Oxford Knee Score and the Knee Society Score, early results showed an improvement from in the Oxford Knee score from 54.4 (+/−5.7) to 27.2 (+/−4.7)*, and the improvement was maintained at 12**, 30**, and 62** months (*P< 0.002; **P< 0.005). The same pattern was repeated with the knee society score where a pre opetrative score of 53.9 (+/−4.8) improved to 87.6 (+/−6.2) at 6 months and was 82.4(+/−8.7) at 62 months.
No infections were recorded, or differences in pre and post-operative flexion were observed at 36 months (P< 0.005) in all patients. However, 3 patients required further manipulation to overcome post-operative stiffness. Plates were removed only for local discomfort, and follow up showed there was no loss of corrective angulation.
Conclusion: These results suggest using the puddu plate is an alternative to unicompartmental or total knee arthroplasty in young active patients with lateral compartment osteoarthritis, without significant morbidity.
Honorary Secretary – Mr Roger Smith. Correspondence should be addressed to BASK at the Royal College of Surgeons, 35 - 43 Lincoln’s Inn Fields, London WC2A 3PN
