The influence of the peroneus longus muscle on the foot under axial loading; a CT evaluated dynamic cadaveric model study

• Published in: Clinical biomechanics (Bristol) 2016-05, Vol.34, p.7-11
• Main Authors: Dullaert, K, Hagen, J, Klos, K, Gueorguiev, B, Lenz, M, Richards, R.G, Simons, P
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Anatomy; Arches; Biomechanical study; Cadaver; Deformation; Dynamic tests; Female; First ray instability; Flatfoot - physiopathology; Foot - diagnostic imaging; Foot - physiology; Hallux valgus; Humans; Joint Dislocations - physiopathology; Legs; Male; Medial longitudinal arch; Middle Aged; Muscle, Skeletal - diagnostic imaging; Muscle, Skeletal - physiology; Muscles; Pathology; Peroneus Longus function; Physical Medicine and Rehabilitation; Rotation; Tarsal Joints - diagnostic imaging; Tarsal Joints - physiology; Tendons; Tendons - diagnostic imaging; Tendons - physiology; Tomography, X-Ray Computed; Weight-Bearing
• ISSN: 0268-0033; 1879-1271
• DOI: 10.1016/j.clinbiomech.2016.03.001

Abstract Background Subtle hypermobility of the 1st tarsometatarsal joint can occur concomitantly with other 1st ray pathology and can be difficult to diagnose. The Peroneus Longus might influence the stability of this joint. Collapse of the medial longitudinal joint is common in flatfoot deformity and the Peroneus might also play a part in correcting Meary's angle. Methods A radiolucent frame was used to simulate weightbearing during CT examination. Eight pairs of fresh-frozen feet were imaged in neutral position in non-weightbearing (75 N), weightbearing state (700 N) and with 15 kg weights hung from the Peroneus. Measurements included 1st metatarsal rotation, intermetatarsal angle, 1st tarsometatarsal joint subluxation and Meary's angle. Findings Axial loading significantly affected the 1st tarsometatarsal joint and Meary's angle significantly increased (p = 0.01). Loading the tendon significantly increased the 1st metatarsal rotation and had a decreasing effect on the intermetatarsal angle trending towards the unloaded state (p = 0.001). There was a trend toward significance in restoring the 1st tarsometatarsal subluxation (p = 0.07). The Meary's angle increased further with loading the tendon however this was not significant (p = 0.52). Interpretation A significant effect weightbearing has on the medial longitudinal arch and 1st tarsometatarsal joint was observed. Loading the tendon did not correct the Meary angle, it improved 1st metatarsal subluxation but increased axial rotation. While clinical investigation is needed, the study calls into question the importance of the Peroneus in maintaining the medial longitudinal arch and raises concerns about rotation deformity of the 1st metatarsal following hallux valgus correction that does not incorporate 1st tarsometatarsal arthrodesis. Clinical relevance These data and study model will provide more insight in foot pathology. What is known about the subject Hallux valgus is a common problem of the foot. There exists controversy over the influence of lower leg muscles on the severity of the disease. Several different measurements are used in this study. Weightbearing significantly affects the anatomy of the foot. No reliable information is available concerning the influence of the Peroneus muscle. What this study adds to existing knowledge This study confirms the influence of weightbearing on the anatomy of the foot. It reveals the deformity that results from weightbearing and the impact the Peroneus muscl