Subtalar Joint’s Middle Facet Yields Insight into Flatfoot
Many foot and ankle surgeons would relish a simple measurement made from a readily available imaging modality to help detect whether patients with adult acquired flatfoot deformity (AAFD) are at high risk for progressive collapse—and to help them with surgical planning. According to the findings from a case-control study by de Cesar Netto et al. in the October 16, 2019 issue of The Journal of Bone & Joint Surgery, that wish may soon be realized.
The authors made standing, weight-bearing computed tomography (CT) scans of 30 patients with stage-II AAFD (mean age of 57.4 years) and 30 matched controls (mean age of 51.8 years). From those images, 2 fellowship-trained surgeons, who were blinded regarding the patient cohorts, measured the amount of subluxation (percentage of uncoverage) and the incongruence angle of the middle facet of the subtalar joint in the coronal plane. The authors found substantial to almost perfect intraobserver and interobserver reliability for both measurements.
Based on these middle-facet measurements, the mean value for joint uncoverage in patients with AAFD was 45.3% compared with 4.8% in controls. Similarly, the mean incongruence angle in the AAFD group was 17.3° in the AAFD group and 0.3° in controls. Further analysis led the authors to conclude that “an incongruence angle of >8.4° and an uncoverage percentage of 17.9% were found to be highly diagnostic for symptomatic stage-II AAFD.”
De Cesar Netto et al. say the biomechanics of the subtalar joint made focusing on the middle facet a sensible approach, and they attributed the high reliability of the measurements to the relatively simple anatomy of the middle facet. Still, because clinical outcomes were not assessed in this study, the role of the middle facet as a marker of peritalar subluxation and a tool for deformity correction in AAFD patients needs further investigation in prospective, longitudinal studies.
Recurrent Instability Common after Initial Shoulder Injuries
A prospective observational study of 45 intercollegiate soccer, basketball, lacrosse, and football players found that 73% of the enrollees returned to their sport within a week after an initial anterior shoulder injury; however, 64% of those who returned to competition during the same season experienced a subsequent injury to the same shoulder. Recurrent events were as common in athletes who initially experienced a subluxation as in those who had dislocations. All athletes in the study underwent a standardized accelerated rehab program without shoulder immobilization following the initial injury.
In presenting the data at the 2014 meeting of the American Orthopaedic Society for Sports Medicine, Jonathan Dickens, MD, noted that among the four post-injury outcome scores used in the study, the Western Ontario Shoulder Instability Index (WOSI) and the Simple Shoulder Test (SST) were the most predictive of an athlete’s ability to return to play. While the sample size was small, this is nevertheless the largest study of its kind to date.
To view the abstract, click here.
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