Does Treatment of the Tibia Matter in Bipolar Chondral Defects of the Knee? Clinical Outcomes with Greater Than Two Years Follow-Up

Objectives: The purpose of this study was twofold: 1) to investigate the optimal treatment of bipolar tibiofemoral cartilage lesions by comparing femoral osteochondral allograft (OCA) with tibial debridement to bipolar lesions treated with femoral OCA and tibial microfracture and 2) to compare the outcomes of bipolar lesions with isolated femoral defects treated with OCA.Methods: A series of 36 patients undergoing femoral OCA for bipolar lesions was identified. Group 1 contained 20 patients with tibial lesions treated with debridement, Group 2 contained 16 patients with tibial lesions treated with microfracture, and Group 3 (control group) contained 20 patients with isolated femoral lesions treated with OCA. Group 3 was matched by gender, BMI, laterality, and OCA size to Groups 1 and 2. Patient-specific, defect-specific data was collected. Patient reported outcomes (PROs) including International Knee Documentation Committee (IKDC) scores, Short Form 12 (SF-12) scores, Knee Injury and Osteoarthritis Outcome Scores (KOOS), and Lysholm scores, were recorded. All patients had greater than two-year follow-up.Results: There were no significant differences between the three groups in terms of gender, body mass index (BMI), number of previous surgeries, femoral or tibial defect size, and OCA size. Preoperative to postoperative patient reported clinical outcomes (PROs) demonstrated statistical and clinically meaningful improvement in all 3 groups (p < 0.05), without differences between groups (Figure 1). Patient-specific and defect-specific factors did not significantly correlate with PROs. The graft survivorship for Group 1 was 85% at 4.5 years, 100% for Group 2 at 2.5 years, and 95% for Group 3 at 3.8 years.Conclusion: Regardless of tibial treatment, debridement or microfracture, patients with bipolar cartilage lesions treated with femoral OCA have significant and clinically meaningful improvements in PROs, which are comparable to isolated femoral defects treated with OCA. In addition, bipolar lesions treated with OCA had excellent graft survivorship at greater than two-years follow-up.