Differences and similarities in muscle architecture of fibularis longus and brevis-An observational descriptive cross-sectional and feasibility study.

BACKGROUND: The fibularis longus (FL) muscle is larger in volume than fibularis brevis (FB) and is therefore claimed to be the stronger evertor of the two. Clinical observation of FL and FB tendon rupture show that injury to the FB has a serious negative effect on hindfoot eversion. This implies that the FB is the stronger and more important evertor. The strength of a muscle is not purely based on its volume, and the observed discrepancy between the FB and FL may be due to differences in muscle architecture. This study compares the muscle architecture of FL with FB. METHODS: Sixteen legs from eight formaldehyde-fixed human specimens, mean age 83 (range 72-89) years, were dissected. The volume, fibre lengths and fibre pennation angles for both muscles were measured and the physiological cross-sectional area (PCSA) was calculated. RESULTS: The FL was always larger than the FB, with an individual difference in volume that varied from 1.4 to 4.6 times larger with a mean difference of 17 ml (95% CI 14-20; p < 0.001). Mean fibre lengths were 9 mm (95% CI 2-16; p = 0.015) longer in FL than in FB. The mean pennation angle was 9.6 degrees in FL and 8.8 degrees in FB, this difference was not significant (p = 0.32). The mean PCSA for FL was 3 cm2 (95% CI 2-4) larger than for FB (p < 0.001). CONCLUSIONS: With our sample set, the hypothesis that the muscle architecture can explain the clinical discrepancy between the FL and FB, was not supported. The difference in hindfoot eversion might instead depend on the different moment arms of FL and FB and the effect forefoot abduction has on hindfoot eversion.

Cavovarus Foot Surgery Including a Peroneus Longus Transfer: A 2- to 6-Year Follow-up.

BACKGROUND: The primary aim of this longitudinal study was to describe patient satisfaction and clinical outcome at least 2 years following cavovarus foot surgery, utilizing a peroneus longus to brevis transfer, lateral ligament reconstruction, and corrective osteotomies of the first metatarsal, occasionally with the added calcaneal osteotomy. METHODS: Sixteen patients (17 feet) were examined in 2010-2012, 3.5 (range, 2-6.5) years after cavovarus foot surgery performed in 2004-2010 utilizing a peroneus longus to brevis transfer, lateral ligament reconstruction, and osteotomy of the first metatarsal with or without additional calcaneal osteotomy. The mean age at surgery was 45 years. Evaluation at baseline before surgery and at follow-up assessed patient satisfaction, using the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score. At follow-up, visual analog scale (VAS) score for pain at walking was recorded, and a clinical and radiographic evaluation was included. RESULTS: The mean AOFAS score improved from 57 (SD 11) to 83 (SD 12.5) points, with an average score improvement of 25 score points (95% confidence interval 16-35, P < .0001). Postoperative VAS score for pain at walking was mean 2 (range, 0-6). All feet had a residual cavovarus both clinically and on the radiographs. CONCLUSION: Patient satisfaction and clinical outcome was shown to improve pre- to postsurgery at intermediate follow-up after peroneus longus to brevis transfer and metatarsal osteotomies with or without additional calcaneal osteotomies as part of a cavovarus foot correction. LEVEL OF EVIDENCE: Level IV, case series.

Transient bone marrow edema of the foot and ankle and its association with reduced systemic bone mineral density.

BACKGROUND: Transient bone marrow edema in the foot and ankle is an uncommon condition that should be distinguished from early avascular necrosis, stress fracture, or bone bruise. The diagnosis is based on the clinical presentation of pain with weightbearing without a history of trauma, combined with typical findings on magnetic resonance imaging. The etiology is not known, but recent case reports have suggested a possible link to systemic osteoporosis. This study examined the relationship between transient bone marrow edema of the foot and ankle and low systemic bone mineral density. MATERIAL AND METHODS: Over a period of 2 years, ten patients (eight women and two men) who were referred to our foot and ankle clinic were diagnosed as having transient bone marrow edema. Their mean age was 59 years. All underwent dual energy X-ray absorptiometry (DEXA) scan and were tested for serum vitamin D levels. The patients were treated with either a controlled ankle motion (CAM) walker or a stiff-soled postoperative shoe and all recovered in 5 to 10 months. RESULTS: Four patients were found to have osteoporosis and five had osteopenia. Only one patient had normal bone density. Serum vitamin D levels were low in nine patients, and normal in one. CONCLUSION: Our study found a strong association with transient bone marrow edema in the foot and ankle and low systemic bone mineral density, which appears to be due to a vitamin D deficiency. We recommend that, when TBME is diagnosed, patients should be referred for assessment and treatment of their bone mineral density.