Clinically assessed knee joint laxity as a predictor for reconstruction after an anterior cruciate ligament injury: a prospective study of 100 patients treated with activity modification and rehabilitation.

BACKGROUND

The association of early knee joint laxity with the need for later reconstruction of the anterior cruciate ligament has not been extensively studied.

HYPOTHESIS

The grade of knee laxity can be used as an early predictor of the need for later reconstruction.

STUDY DESIGN

Cohort study (prognosis); Level of evidence, 2.

METHODS

One hundred consecutive patients with an acute arthroscopically verified total anterior cruciate ligament rupture were followed prospectively for 15 years. Lachman and pivot-shift tests were performed with the patient under general anesthesia before arthroscopy. After 3 months, the tests were repeated in an ordinary clinical setting. All patients underwent rehabilitation as the first choice of treatment. Anterior cruciate ligament reconstruction was performed only in cases of significant reinjuries (n = 16) or reparable meniscal lesions (n = 6) at a mean of 4 years after injury (range, 4 months-11 years). After 15 years, 94 patients were available for follow-up.

RESULTS

Of the later reconstructed patients (n = 18), 82% had a high-grade Lachman test under anesthesia compared with 63% of the nonreconstructed patients (n = 45; P = .048). At 3 months, 44% of the nonreconstructed patients (n = 32) had a high-grade Lachman test compared with 82% of the reconstructed patients (n = 18; P = .007). Twenty-five patients displayed a normal pivot-shift test at 3 months, of whom 1 underwent later reconstruction (P = .009). A high-grade pivot-shift test at 3 months was associated with an 11.4 relative risk for reconstruction.

CONCLUSION

A positive pivot-shift test at 3 months after injury in an awake patient is the strongest predictor for the future need for reconstruction. Furthermore, a normal pivot-shift test at 3 months indicates a low risk for reconstruction and is characteristic for copers.