Nonhamstring ACL grafts were linked to better scores, with no sign that MCL status changed the effect

Design

Prospective multicentre registry cohort with inverse probability weighting

Population

489 of 722 eligible patients having primary ACL reconstruction, with or without MCL injury

Primary outcome

International Knee Documentation Committee subjective score

Effect

Nonhamstring graft: beta 7.89 (95% CI 3.45 to 12.33); graft by operative MCL interaction beta -7.02 (95% CI -15.26 to 1.22)

This French registry study of 489 patients (from 722 eligible) who had primary ACL reconstruction compared hamstring and nonhamstring grafts, and asked whether a concurrent medial collateral ligament injury changed the result. The worry has been that harvesting the hamstrings might weaken medial stability in knees with MCL damage.

Nonhamstring grafts were associated with higher IKDC subjective scores (beta 7.89, 95% CI 3.45 to 12.33) and Subjective Knee Value scores. Isolated ACL injuries scored higher than ACL injuries with a nonoperatively treated MCL (beta 10.41, 95% CI 6.48 to 14.34). The graft-by-MCL interaction was not statistically significant (operative MCL: beta -7.02, 95% CI -15.26 to 1.22).

A non-significant interaction does not prove that MCL status is irrelevant, and the study could not exclude a modest difference. Graft choice was not randomised, and a third of eligible patients lacked complete data.

• Weigh patient factors, activity level and surgeon experience when choosing a graft; this study does not prove one graft is better.
• Do not assume a hamstring graft is unsuitable when an MCL injury is present.
• Counsel that combined ACL and MCL injuries tend to have lower scores than isolated ACL tears.
• Record graft type and MCL management to allow comparison at follow-up.

Why it matters

It tests a common reason surgeons give for avoiding hamstring grafts in combined injuries.

Don't overread it

Observational, with propensity weighting and incomplete data in about a third of patients; it does not show that nonhamstring grafts cause better outcomes.

The statistics, in plain English

A beta of 7.89 means that, on average and after weighting, IKDC scores were about 8 points higher with nonhamstring grafts. Whether 8 points matters to a patient is a separate question. The interaction interval includes zero, so the data cannot confirm or exclude a difference.

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