Patients with an osteochondral lesion of the talus (OLT) and chronic lateral ankle instability (CLAI) have an increased proportion of larger chondral lesions compared with patients without instability. They are also more likely to have an increased incidence of lateral OLTs, additional chondral lesions at the tip of the medial malleolus, and a higher likelihood of treatment failure.

OLT is a form of chondral injury in the ankle for which trauma is the dominant etiology. Although CLAI can be considered a form of ongoing microtrauma and thus may influence lesion prognosis and characteristics, the association between the duration of the instability and the severity of OLT remains controversial. Moses Lee, MD, Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea, presented the results of a study designed to determine the effect of, and clinical outcomes associated with, long-standing ankle instability in OLT.

The study comprised 420 patients who received primary arthroscopic marrow stimulation for OLT, 74 with CLAI and 148 without CLAI, matched for age, sex, body mass index, and trauma history. All patients had a history of repetitive inversion sprain and positive findings on stress radiography. Participants were approximately 36 years old, around 60% were men, and study follow-up was approximately 53 months. Demographics and lesion characteristics were compared using preoperative magnetic resonance imaging (MRI) and arthroscopy. Clinical evaluations (the visual analog scale [VAS] for pain, American Orthopaedic Foot & Ankle Society [AOFAS] Ankle-Hindfoot score, and Foot and Ankle Outcomes Score [FAOS]) were performed at 6 weeks; 3, 6, and 12 months; then annually. Radiographic and arthroscopic analysis of the lesion was based on the preoperative MRI with an ellipse formula of coronal length by sagittal length times 0.79. Lesions ≥ 150 mm² were defined as large.

Most OLTs were located on the medial side; however, the incidence of lateral OLTs was significantly increased in patients with CLAI vs those without it (P < .018). Patients with CLAI were also significantly more likely to have a chondral lesion at the tip of the medial malleolus (42% vs 7%; P < .018).

The proportion of large lesions was significantly higher among patients with OLT and CLAI (20.2%) compared with those without CLAI (9.4%; P = .024), although the average lesion size was not significantly different (99.5 ± 51.8 mm² vs 86.9 ± 46.2 mm²). Neither degree nor duration of instability correlated with lesion size. Having CLAI was associated with an increase in ossicle and osteophyte lesions and with syndesmosis widening (all P < .04).

Compared with their preoperative scores, clinical outcomes (VAS and AOFAS) were improved for both groups at the last follow-up; however, there was no significant difference in clinical outcomes between the groups at the preoperative stage or at the last follow-up. Significantly more patients with CLAI were considered treatment failures (AOFAS score < 80; P = .034). Scores on the FAOS were similar for the 2 groups, except for the Sports/Recreation subscale, which was significantly worse (P = .005) for patients with instability.

These results support earlier studies showing an increase in chondral lesions at the tip of the medial malleolus [Sugimoto K et al. J Bone Joint Surg Am. 2009]. Importantly, they also provide data indicating increased clinical failure among these patients and inferior performance in sports and recreational activities.