In vivo cartilage contact strains in patients with lateral ankle instability

Abstract

Damage to the anterior talofibular ligament (ATFL) and cacaneofibular ligament (CFL) during ankle sprain may be linked to the development of osteoarthritis. Altered tibiotalar kinematics have been demonstrated in these patients, but the effects of lateral ankle instability (LAI) on in vivo cartilage strains have not been described. We hypothesized that peak cartilage strains increase, and the location is shifted in patients with ATFL injuries. We used 3-D MRI models and biplanar fluoroscopy to evaluate in vivo cartilage contact strains in seven patients with unilateral LAI. Subjects had chronic unilateral ATFL injury or combined ATFL and CFL injury, and were evaluated with increasing load while stepping onto a force plate. Peak cartilage strain and the location of the peak strain were measured using the contralateral normal ankle as a control. Ankles with LAI demonstrated significantly increased peak strain when compared with ATFL-intact controls. For example, at 100% body weight, peak strain was 29±8% on the injured side compared to 21±5% on the intact side. The position of peak strain on the injured ankle also showed significant anterior translation and medial translation. At 100% body weight, the location of peak strain in the injured ankle translated anteriorly by 15.5±7.1mm and medially by 12.9±4.3mm relative to the intact ankle. These changes correspond to the region of clinically-observed osteoarthritis. Chronic LAI, therefore, may contribute to the development of tibiotalar cartilage degeneration due to altered cartilage strains.

T2 mapping of the articular cartilage in the ankle: Correlation to the status of anterior talofibular ligament

“…The present results can be explained by those of previous studies. Bischof et al 33 reported that patients with ATFL injuries showed increased and anteromedially shifted peak cartilage contact strain using MRI and orthogonal fluoroscopy to determine the in vivo cartilage contact strains. Caputo et al 34 reported altered anterior translation, internal rotation, and superior translation of the talus relative to the tibia in ATFL-deficient ankles using in vivo kinematic measurements of the tibiotalar joint.…”

Evidence review for the 2016 International Ankle Consortium consensus statement on the prevalence, impact and long-term consequences of lateral ankle sprains

“…If the initial LAS is an underlying cause of osteochondral lesions, recurrent LASs and episodes of giving way likely exacerbate contact stress adaptations,52 further advancing degenerative changes. While speculative, this would place a premium on restoring appropriate biomechanics and motor control following an LAS in order to mitigate cartilage degeneration.…”

Operative treatment of lateral ligament instability

“…Patients may have a subjective sense of instability where an innocuous misstep may lead to another ankle injury [8]. Recurrent ankle sprains may alter the biomechanics at the ankle joint which can potentially lead to cartilage degeneration over time [9][10][11][12][13]. Up to 93% of patients with ankle instability have associated intra-articular pathology [14][15][16].…”