ABSTRACT
BACKGROUND: Pressure distribution in the ankle joint is known to be dependent on various factors, including hindfoot alignment. We seek to evaluate how hindfoot alignment affects contact pressures in the ankle joint in the setting of supination external rotation (SER) type ankle fractures. METHODS: SER fractures were created in 10 human cadaver lower extremity specimens, simulating progressive stages of injury: without fracture (step 0), SER fracture and intact deltoid ligament (step 1), superficial deltoid ligament disruption (step 2), and deep deltoid ligament disruption (step 3). At each step, varus and valgus alignment was simulated by displacing the calcaneal tuberosity 7 mm medial or lateral. Each limb was axially loaded following each osteotomy at a static load of 350 N. The center of force (COF), contact area (CA), and peak contact pressure (PP) under load were measured, and radiographs of the ankle mortise were taken to analyze the medial clear space (MCS) and talar tilt (TT). RESULTS: The COF (5.3 mm, P = .030) and the CA (-188.4 mm2, P = .015) changed in step 3 in the valgus hindfoot alignment compared to baseline parameters, indicating the importance of deep deltoid ligament integrity in maintaining normal ankle joint contact stress in the valgus hindfoot. These changes were not seen in the setting of varus alignment (COF: 2.3 mm, P = .059; CA -121 mm2, P = .133). PP were found to not change significantly in either varus or valgus (varus: -4.9 N, P = .132; valgus: -4 N, P = .464).The MCS demonstrated widening in step 3 compared to step 2 (0.7 mm, P = .020) in both varus and valgus hindfoot. The TT increased significantly in step 3 in the valgus hindfoot (2.8 degrees, P = .020) compared to step 0. CONCLUSION: SER-IV fractures with valgus hindfoot alignment showed significant changes in pressure distribution and radiographic parameters when compared to SER-IV fractures with varus hindfoot alignment. CLINICAL RELEVANCE: Based on this cadaver modeling study, patients with SERIV fracture with varus hindfoot alignment and complete deltoid ligament lesion may not need fracture fixation, whereas those with valgus hindfoot alignment likely need fracture fixation.
ABSTRACT
Peripheral neuropathies after orthopedic surgery are a rare complication (0.14 % on average) but with a significant impact on quality of life that requires close monitoring and physiotherapy sessions. Surgical positioning is a preventable cause responsible for about 20-30 % of the observed neuropathies. Orthopedic surgery is one of the most affected areas because of the positions maintained for long periods of time that are particularly at risk of compression or nerve stretching. The objective of this article is to list, through a narrative review of the literature, the most frequently affected nerves, the clinical presentation as well as the risk factors, and to draw general practitioner's attention to this issue.
Les neuropathies périphériques après une intervention chirurgicale orthopédique sont une complication rare (0,14 % en moyenne) mais avec un impact important sur la qualité de vie, et nécessitent un suivi rapproché et des séances de physiothérapie. Parmi les causes évitables, le positionnement opératoire est responsable d'environ 20 à 30 % des neuropathies observées. La chirurgie orthopédique représente l'un des secteurs les plus touchés en raison des positions à risque de compression ou d'étirement nerveux maintenues pendant de longues durées. L'objectif de cet article est de présenter, par une revue narrative de la littérature, les nerfs les plus fréquemment touchés, le tableau clinique ainsi que les facteurs de risques associés, afin de sensibiliser le médecin de premier recours à cette problématique.
