Summary

Older patients with grade 3 or 4 chondral damage at time of ACL reconstruction have an increased risk of loss of joint space and the presence of osteoarthritis at minimum 10-year follow-up.

Abstract

Introduction

Recent systematic reviews have reported higher rate of knee osteoarthritis (OA) following transtibial ACL reconstruction compared to anteromedial drilling (49.3% vs 25.4%) at 5 years. The purpose of this study was to determine predictors of joint space narrowing at a minimum of 10-year follow-up after ACL reconstruction using a transtibial technique and bone-patellar tendon-bone graft by a single surgeon.

Methods

Patients who underwent primary ACL reconstruction with single-bundle, bone-patellar tendon-bone ACL reconstruction using a transtibial technique by the senior author were included. All patients underwent a similar conservative, rehabilitation program. Patients underwent minimum 10-year follow-up as part of a quality control study at our clinic. At follow-up, data collected included knee range of motion, Lachman, pivot shift, and KT-1000 testing. Plain radiographic series included anteroposterior, posteroanterior, lateral, Rosenberg, and 3-foot standing films. All joint spaces were measured by an independent evaluator.

Results

Seventy-three patients (33 females, 40 males; mean age 38±11 years) completed minimum 10-year follow-up (mean 14.7±4 years). One patient (1.4%) required a revision ACL reconstruction. Seven patients (9.6%) required arthroplasty and joint space was recorded as 0mm. At >10-year follow-up, the mean medial joint space was 3.9±2.6mm (range 0 to 8.4mm) and the mean lateral joint space was 4.4±2.8mm (range 0 to 11mm). Fifteen knees had 2mm or less of medial joint space and 13 knees had 2mm or less of lateral joint space. Eight knees had bilateral joint space narrowing (2mm or less of both medial and lateral joint space). 32 knees had chondral defects, 44 had medial meniscus tears (21 complex, 10 flap, 13 horizontal, 0 radial) and 43 had lateral meniscus tears (8 complex, 11 flap, 14 horizontal, 10 radial).
Age was negatively correlated with medial joint space (r=-0.343; p=0.008) and lateral joint space (r=-0.384; p=0.003). Knees with Outerbride grade 3 or 4 chondral defects at time of ACL reconstruction had significantly less medial joint space (2.8 vs. 5.4mm; p=0.001) and lateral joint space (2.5 vs 5.0mm; p=0.001) at 14.7-year follow-up. Knees with medial meniscus pathology had greater joint space narrowing compared to knees without medial meniscus pathology (3.5 vs 5.6mm; p=0.001). Independent predictors of medial joint space at 10-year follow-up were age and the presence of chondral defects at time of ACL reconstruction (R2=0.302; p=0.001).

Conclusion

In this single surgeon cohort, joint space at 10 years following ACL reconstruction using a transtibial technique was associated with age, meniscus pathology, and presence of chondral defects at time of surgery. Age and the presence of chondral defects were independent predictors of joint space. Older patients with grade 3 or 4 chondral damage at time of ACL reconstruction have an increased risk of loss of joint space and the presence of osteoarthritis at long-term follow-up.