SLR - June 2023 - Michael Higham, DPM PGY-2
Title: Anatomic Features of Patients With Recurrent Peroneal Tendon DislocationReference: Nishimura A, Nakazora S, Senga Y, Fukuda A, Sudo A. Anatomic Features of Patients With Recurrent Peroneal Tendon Dislocation. Am J Sports Med. 2023;51(5):1312-1318. doi:10.1177/03635465231158100
Level of Evidence: Cross-sectional Study; Level of Evidence, 3.
Scientific Literature Review
Reviewed By: Michael Higham, DPM PGY-2
Residency Program: Baylor Scott and White Temple Texas
Podiatric Relevance: This article discusses whether fibular groove depth, accessory peroneal muscles, and/or low-lying peroneus brevis muscle belly is associated with recurrent peroneal tendon dislocation. The relevance to podiatry is an improved understanding of the pathophysiology that is associated with peroneal subluxation, with the goal of improving surgical decision making, through insight into potential causative etiologies.
Methods: All patients who underwent surgery for peroneal dislocation at their institution were included (n=30). Their imaging was compared to imaging from individuals, age and sex matched, who had received both MRI and CT for other musculoskeletal pathology (n=30). Their exclusion criteria included patients with: ankle fracture, lateral ankle instability, or congenital abnormalities. The imaging was reviewed at the level of the tibial plafond (TP) and midway between the tibial plafond and the fibular tip (MP). The appearance of the malleolar groove (convex, concave, or flat) and the posterior tilting angle of the fibula were assessed on CT. The presence of accessory peroneal muscles, height of the peroneus brevis muscle belly, and volume of the peroneal muscle and tendons were assessed on MRI.
Results: At both the TP and MP levels there were no statistically significant differences between the peroneal dislocation group and the control group in the following metrics: malleolar groove shape (convex/flat/concave), posterior tilting angle of the fibula, accessory peroneal muscles, or the cross-sectional area of the peroneal tendons divided by the cross-sectional area of the fibula. However, there was a statistically significant difference found in the height of the peroneus brevis muscle and in the cross-sectional area of the peroneus brevis muscle belly divided by the cross-sectional area of the fibula at both the tibial plafond and midpoint.
Conclusions: The authors conclude: low lying and/or enlarged peroneus brevis muscle belly is potentially contributing to peroneal tendon subluxation; they hypothesize that increased volume within the retromalleolar space could be attenuating the superior fibular retinaculum. They further question the role of fibular groove deepening in the treatment of peroneal tendon subluxation. Although I agree that low lying muscle belly may play a role in peroneal subluxation, I believe there are some limitations/shortcomings to this study that make me reluctant to apply these conclusions with confidence to my patient care.
1. Selection bias: The control group was selected from a population with other ankle pathology, the groups were only matched by age and sex, and the patients with chronic lateral ankle instability were excluded.
2. There was no evaluation for peroneal retinaculum tear or attenuation. The fibrocartilaginous lip of the fibula was not evaluated, merely the osteology of the fibula.
3. Myositis from subluxation could lead to overestimation of the peroneus brevis muscle to fibula ratios, however, the height of the peroneus brevis muscle belly should be unaffected.
4. Sample size: with a total sample size of 60, care must be taken to extrapolate this data to the general population.