The Influence of Preoperative Radiographic Patello-femoral Osteoarthritis and Patellar Bone Marrow Edema on Patellofemoral-Specific Outcome Scores Following Unicompartmental Knee Arthroplasty.

Abstract

The aim of this study was to assess the impact of patello-femoral osteoarthritis (PFOA) and patellar bone marrow edema (PBME) on outcomes in the intermediate term (2 years) following unicompartmental knee arthroplasty (UKA). Additionally, we sought to examine the relationship between PBME severity and clinical prognosis. A retrospective analysis was conducted on 154 patients who underwent UKA, with a minimum follow-up of 2 years (average 2.4). Patients were categorized into three groups: group A (no PFOA or PBME), group B (PFOA, but no PBME), and group C (both PFOA and PBME). Group A comprised 82 knees, group B included 52 knees, and group C had 20 knees. At the latest follow-up, a patient-reported questionnaire assessed range of motion (ROM), visual analog scale (VAS), knee society score (KSS), and Kujala score. The ROM, VAS, KSS, and Kujala scores were unaffected by PFOA. However, patients who had PBME showed reductions in ROM and Kujala scores at 24 months: ROM was 114.9° in group C versus 121.0 and 121.5° in groups A and B, respectively; Kujala scores were 85.9 versus 91.8 and 90.4, respectively. Further, PBME grade III patients experienced declines in ROM (109.5 versus 116.3°), KSS scores (82.8 versus 87.5), and Kujala scores (80.8 versus 88.6) compared to grade I (P < 0.05). The presence of PFOA did not affect intermediate-term (2 years) outcomes in patients undergoing UKA, suggesting it should not be considered a contraindication. Conversely, preoperative PBME was associated with less favorable short-term outcomes, indicating it may be a risk factor for poorer prognosis in UKA. Level IV.