Minimum 10-year follow-up of patients after an acute, isolated posterior cruciate ligament injury treated nonoperatively

Abstract

Background: Few studies report long-term subjective or objective results for acute, isolated posterior cruciate ligament (PCL) injuries in patients followed prospectively.

Hypothesis: Subjective or objective results will not differ based on PCL laxity.

Study design: Case series; Level of evidence, 4.

Methods: Sixty-eight patients with an acute, isolated PCL injury were treated nonoperatively and followed prospectively with yearly subjective surveys and periodic objective evaluations. Physical examination included evaluation of range of motion, effusion, and quadriceps strength; radiographic grading of osteoarthritis; and measurements of joint space width. Subjective follow-up included the International Knee Documentation Committee (IKDC) and modified Cincinnati Knee Rating System (CKRS) surveys.

Results: A total of 44 patients were available for both objective and subjective evaluations at a mean of 14.3 years (range, 10-21 years) after injury. All 68 patients underwent subjective follow-up at a mean of 17.6 years after injury. The mean quadriceps muscle strength was 97% of the noninvolved leg; all patients maintained normal knee range of motion. The overall grade of radiographs was rated as normal in 26 patients (59%), nearly normal in 13 patients (30%), abnormal in 4 patients (9%), and severely abnormal in 1 patient (2%). The grade of osteoarthritis on radiographs was not different in any knee compartment based on PCL laxity grade. Five patients (11%) had medial joint space narrowing greater than 2 mm. Mean IKDC and modified CKRS subjective scores at a mean of 17 years after injury were 73.4 ± 21.7 and 81.3 ± 17.4, respectively; there was no difference in subjective scores between PCL laxity grades. There was no difference in subjective scores between patients who completed a minimum 10-year objective follow-up and patients who completed surveys only.

Conclusion: Long-term results after an isolated PCL injury show that patients remain active, have good strength and full knee range of motion, and report good subjective scores. The prevalence of moderate to severe osteoarthritis was 11%. Results were not different based on PCL laxity grade. This natural history study of nonoperatively treated PCL injuries can serve as a baseline for comparison with patients treated with PCL reconstruction.

Keywords: isolated injury; long-term outcome; natural history; osteoarthritis; posterior cruciate ligament.