Worsening Knee Osteoarthritis Features on Magnetic Resonance Imaging 1 to 5 Years After Anterior Cruciate Ligament Reconstruction

Abstract

Background: An anterior cruciate ligament (ACL) injury is a well-established risk factor for the long-term development of radiographic osteoarthritis (OA). However, little is known about the early degenerative changes (ie, <5 years after injury) of individual joint features (ie, cartilage, bone marrow), which may be reversible and responsive to interventions.

Purpose: To describe early degenerative changes between 1 and 5 years after ACL reconstruction (ACLR) on magnetic resonance imaging (MRI) and explore participant characteristics associated with these changes.

Study design: Case-control study; Level of evidence, 3.

Methods: Seventy-eight participants (48 men; median age, 32 years; median body mass index [BMI], 26 kg/m²) underwent 3.0-T MRI at 1 and 5 years after primary hamstring autograft ACLR. Early tibiofemoral and patellofemoral OA features were assessed with the MRI Osteoarthritis Knee Score. The primary outcome was worsening (ie, incident or progressive) cartilage defects, bone marrow lesions (BMLs), osteophytes, and meniscal lesions. Logistic regression with generalized estimating equations evaluated participant characteristics associated with worsening features.

Results: Worsening of cartilage defects in any compartment occurred in 40 (51%) participants. Specifically, worsening in the patellofemoral and medial and lateral tibiofemoral compartments was present in 34 (44%), 8 (10%), and 10 (13%) participants, respectively. Worsening patellofemoral and medial and lateral tibiofemoral BMLs (14 [18%], 5 [6%], and 10 [13%], respectively) and osteophytes (7 [9%], 8 [10%], and 6 [8%], respectively) were less prevalent, while 17 (22%) displayed deteriorating meniscal lesions. Worsening of at least 1 MRI-detected OA feature, in either the patellofemoral or tibiofemoral compartment, occurred in 53 (68%) participants. Radiographic OA in any compartment was evident in 5 (6%) and 16 (21%) participants at 1 and 5 years, respectively. A high BMI (>25 kg/m²) was consistently associated with elevated odds (between 2- and 5-fold) of worsening patellofemoral and tibiofemoral OA features.

Conclusion: High rates of degenerative changes occur in the first 5 years after ACLR, particularly the development and progression of patellofemoral cartilage defects. Older patients with a higher BMI may be at particular risk and should be educated about this risk.

Keywords: anterior cruciate ligament; cartilage; knee; osteoarthritis.

Figure 1.

Worsening of magnetic resonance imaging (MRI)-detected osteoarthritis features from baseline (1 year after anterior cruciate ligament reconstruction [ACLR]) to follow-up (5 years after ACLR). Worsening meniscal lesions include worsening tear, maceration, and extrusion. PF, patellofemoral compartment; TF, tibiofemoral compartment. ^ Stable lesions = participants with no worsening (i.e., no new or progressive features, or BML improvement) * New = participants with no lesion at baseline (ie, MRI Osteoarthritis Knee Score [MOAKS] size score = 0), with score of ≥1 at follow-up for cartilage defects, bone marrow lesions (BMLs) and meniscal lesions (≥2 for osteophytes). ~ Progressive = participants with a lesion at baseline (ie, MOAKS size score >1), with an increase in severity of lesion (ie, at least a 1-point increase in size or depth of lesion). ⌘ Worsening = participants with either progressive or new feature. ✜ Improving = participants with a BML at baseline (ie, MOAKS score ≥1), with a decrease in severity of BML (ie, at least a 1 -point decrease in size of BML).

Figure 2.

Cartilage worsening (increase in the number and severity of defects) in the patellofemoral and tibiofemoral joints at baseline and follow-up. Light grey shading indicates the number of participants with a partial-thickness defect (in absence of a full-thickness defect). Dark grey shading indicates the number of participants with a full-thickness cartilage defect.