SLR - February 2018 - Nathanael T. Smith
Reference: Generalized Ligamentous Laxity Is an Independent Predictor of Poor Outcomes After the Modified Broström Procedure for Chronic Lateral Ankle Instability. Park KH, Lee JW, Suh JW, Shin MH, Choi WJ. Am J Sports Med. 2016 Nov;44(11):2975–2983.Scientific Literature Review
Reviewed By: Nathanael T. Smith, DPM
Residency Program: Chino Valley Medical Center, Chino Valley, CA
Podiatric Relevance: Chronic lateral ankle instability (CLAI) is a commonly encountered pathology. The modified Broström is the procedure of choice of many surgeons to solve this difficult problem. Despite this, some failures still occur. Karlsson et al (1988) reported that general ligament laxity is one of the reasons for recurrent instability. This study aims to isolate and explore this variable as a potential risk factor for failure of the procedure.
Methods: In this retrospective cohort study, a total of 223 patients were divided into laxity and nonlaxity groups using the Beighton 9-point score. Patients were evaluated for osteoarthritis with anteroposterior and lateral ankle radiographs. Instability was defined with stress talar tilt angle (positive being > 10 degrees) and anterior talar displacement (positive being > 4 mm) by the TELOS device pre- and postoperatively. All patients underwent the modified Broström by the same surgeon over a 10-year period and were seen at three, six and 12 months and then yearly by two independent observers. The Karlsson-Peterson ankle score was used at each follow-up. Clinical outcomes were also compared in terms of age, BMI, sex, symptom duration, general ligament laxity, anterior talar displacement, ligament reconstructed, syndesmosis widening, soft-tissue impingement, synovitis, osteochondral lesions of the talus OLT, osteophytes, ossicles and other loose bodies for relevance to the subject. Clinical failure was defined as recurrent instability, further surgical intervention or a Karlsson score less than 80 points during a single review.
Results: Thirty-four patients were identified to have generalized ligament laxity, and eight out of 11 had bilateral procedures. Mean duration of follow-up was 60.1 months, and there were no demographic differences between the two groups. The presence of syndesmosis widening was found to be higher in the laxity group. There was no correlation between the other intra-articular lesions identified. Each group showed functional improvements by the Karlsson score at three and six months but were significantly lower in the laxity group at 12 months and at last follow-up. In the nonlaxity group, 140 (89.2 percent) had excellent or good and 17 (10.8 percent) had fair results, whereas in the laxity group 23 (54.8 percent) had excellent or good and 19 (45.2 percent) had fair results when it came to functional evaluation. Recurrence of instability was seen in 16 out of 199 (8 percent), 10 of which were from the laxity group (23.8 percent) and six of the 157 (3.8 percent) were from the nonlaxity group.
Conclusions: This review demonstrates that generalized ligament laxity is associated with poor survival rates following the modified Broström, which was independent of other clinical factors. The other factors identified, such as syndesmosis widening, OLT, high talar tilt and high anterior talar displacement, were not independent. Some of the limitations of this review include its retrospective design and observer bias based on the clinical index for joint laxity. This is the first study of its kind to identify prognostic significance in generalized ligament laxity as it applies to the modified Broström procedure in treatment of CLAI.