Medial closing-wedge distal femoral varus osteotomy: Symptoms and functional impact in cases of associated patellofemoral osteoarthritis. A two-year follow-up prospective pilot study

Knee. 2020 Jun;27(3):615-623. doi: 10.1016/j.knee.2020.02.001. Epub 2020 May 6.

Abstract

Purpose: To date, indications for distal femoral varus osteotomy (FVO) in cases of associated patellofemoral osteoarthritis (PFO) have yet to be clarified. The purpose of this prospective study is to assess the short-term symptoms, functional and radiological impact of a medial closing-wedge femoral varus osteotomy on the patellofemoral joint in patients with valgus deformities who are afflicted with lateral tibiofemoral osteoarthritis (LTFO) associated with PFO.

Methods: Fourteen patients (15 knees) received a medial closing-wedge femoral varus osteotomy. The functional impact of an FVO on the patellofemoral joint was assessed based on the KOOS-PF (Knee Injury and Osteoarthritis Outcome Score-Patellofemoral Subscale), the Kujala score and the patellofemoral symptoms. Realignment of the patella was measured by the Merchant's patellofemoral congruence angle. The pre- and post-operative symptoms and functional scores were compiled prospectively and compared two years after the surgery.

Results: The Kujala patellofemoral functional scores and the KOOS-PF showed considerable improvement with a differential of +37.5 points ± 20.4 and +42.7 points ± 19.3 (p < .01) respectively. The average Merchant's congruence angle went from 8.8° laterally to 3.6° medially, resulting in medialization of the patella, with a significant difference (p < .01). Based on the specific clinical analysis of the patellar joint, preoperative J-sign was identified in 26.7% of patients (n = 4) and was not found during postoperative examination (p = .1). Preoperative apprehension test was identified in 33.3% of patients (n = 5) against 13.3% (n = 2) after surgery (p = .39). Preoperative pain extension test was identified in 40% of patients (n = 6) against 20% during postoperative clinical analysis (p = .43).

Discussion: Although the threshold of significance for patellofemoral symptoms was not reached, the medial closing-wedge femoral varus osteotomy induces a significant medialization of the patella (Merchant's congruence angle) and improves short-term functional results even with co-existing patellofemoral osteoarthritis. Due to the lack of specificity of the patellofemoral scores, patellofemoral osteoarthritis improvement is difficult to determine on its own, but does not represent a contraindication to FVO.

Level of evidence: III. Prospective clinical study.

Keywords: Distal femoral osteotomy; KOOS-PF score; Kujala score; Patellofemoral osteoarthritis.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Female
  • Femur / diagnostic imaging
  • Femur / surgery
  • Follow-Up Studies
  • Genu Varum / diagnostic imaging
  • Genu Varum / surgery
  • Humans
  • Male
  • Middle Aged
  • Osteoarthritis, Knee / diagnostic imaging
  • Osteoarthritis, Knee / surgery*
  • Osteotomy / methods*
  • Patellofemoral Joint / diagnostic imaging
  • Patellofemoral Joint / surgery*
  • Pilot Projects
  • Prospective Studies
  • Treatment Outcome