Arthroscopic Bone Marrow Stimulation for Non-primary Osteochondral Lesions of the Talus Yields Limited Improvements in Patient-Reported Outcomes Compared to Primary Lesions: A Prospective 2-Year Follow-up Study

BACKGROUND: Our aim in this study was to prospectively assess the patient-reported clinical outcomes of arthroscopic bone marrow stimulation (BMS) for non-primary osteochondral lesions of the talus (OLT) and to compare these with primary cases at 2-year follow-up. The secondary aims were to assess the association of baseline factors with outcomes and the occurrence of adverse events.

METHODS: Patients who underwent arthroscopic BMS were prospectively included and assessed up to 2-year follow-up and were grouped according to non-primary (ie, failed previous OLT surgery) or primary BMS. Patient-reported outcomes were collected at baseline and 2-year follow-up and included the numeric rating scale (NRS) for pain and the Foot and Ankle Outcome Score (FAOS) questionnaires. The primary outcome was the improvement in NRS pain during walking, with a minimal clinically important difference (MCID) of 2.0. Adverse events concerned reoperations and complications during the study period.

RESULTS: Forty-four patients were included: 25 in the primary group and 19 in the non-primary group. Both groups showed a statistically significant improvement in pain and functional outcomes from preoperatively to 2-year follow-up. The improvement in the primary outcome was significantly higher in the primary group (median 3 [IQR: 1-5] out of 10) compared to the non-primary group (median 1 [IQR: 1-3] out of 10), P  = .01. Moreover, 68% (95% CI 46%-85%) reached the MCID compared with 32% (95% CI 13%-57%) in the non-primary group, which was statistically significant ( P  = .03). Baseline variables showed no consistent association with the primary outcome, except for a moderate correlation with age and lower improvements for patients who received concomitant surgery in the primary group. None of the changes in the FAOS sub-scales showed a statistically significant difference between the two groups. Two revision procedures (non-primary group: 11% [95% CI 1%-33%] vs 0% primary group, P  = .2) occurred in the non-primary group. During the study period, 1 case (non-primary group: 5% [1%-26%] vs primary group: 0%, P  = .4) had a complication.

CONCLUSION: The most important finding of this prospective study is that arthroscopic BMS for non-primary OLT yields a significant improvement in patient-reported outcomes compared with baseline, but an inferior improvement compared with primary OLT at 2-year follow-up. On average, approximately two-thirds of BMS-treated primary OLTs reached the MCID compared with one-third in the non-primary group.

LEVEL OF EVIDENCE: Level II, prospective comparative cohort study.