Faculty Bibliography

The treatment of chronic neuropathic pain with revision surgical procedures can be beneficial. A thorough evaluation can help to guide treatment to optimize outcome. With an increasing understanding of the pain-generating mechanisms and the appropriate application of surgical interventions, quality of life and function continues to be improved in patients who have otherwise significant disability.

Previous studies have shown that increasing angulation of the Weil osteotomy produces greater plantar translation of the metatarsal head. Modifications have been proposed to reduce plantar translation. However, there is no evidence that the increased plantar translation with a Weil osteotomy is clinically significant or that these modifications are required. Ten lower extremities consisting of five matched pairs were used to evaluate whether different configurations of the Weil osteotomy altered plantar pressure in a dynamic cadaver model. For each pair, an oblique Weil osteotomy with a 5-mm shift was done on one side and a standard (parallel) Weil osteotomy with a 5-mm shift was done on the matched foot. A 4-mm slice resection and a metatarsal head resection then were done sequentially. Plantar pressures were measured with cyclic loading to 700 N at a frequency of 1 Hz with an F-scan in-shoe sensor on the intact specimens and after each intervention. Increased plantar translation of the metatarsal head with a more oblique Weil osteotomy did not significantly increase plantar pressure, and the 4-mm slice resection did not significantly unload the metatarsal head. Only complete metatarsal head resection significantly unloaded the metatarsal head.

This biomechanical investigation compared two fixation techniques for distal fibular fractures. Elderly cadaver lower extremities with simulated fibula fractures underwent fixation either with a plate and intramedullary Kirschner wires (K-wires) with or without the addition of three screws inserted through the four cortices of the fibula and the tibia. The specimens were axially loaded to body weight on a materials testing machine, and the supinated foot was externally rotated to failure. Displacement at the fracture site was monitored with an extensometer. Comparing the augmented technique with the technique without additional screws, mean stiffness was 460 +/- 100 and 320 +/- 200 N-mm/deg, strength at failure was 31 +/- 10 and 19 +/- 7 N-m, strength at 30 degrees external rotation was 15 +/- 5 and 10 +/- 6 N-m, and axial deformation was 0.04 +/- 0.06 mm and 0.10 +/- 0.04 mm, respectively. All differences were statistically significant.

BACKGROUND:Achieving stable fixation when performing tibiotalocalcaneal arthrodesis can be challenging, especially in osteopenic bone. The purpose of the current investigation was to compare the stiffness and fatigue endurance of blade-plate-and-screw fixation with intramedullary rod fixation in a cadaveric model. METHODS:In ten matched pairs of fresh-frozen cadaveric legs, a tibiotalocalcaneal arthrodesis was performed with use of a blade-plate and a 6.5-mm sagittal screw in one leg and with use of an intramedullary rod in the contralateral leg. After an initial load-deformation curve was obtained, each specimen was loaded to 270 N through 250,000 cycles at a rate of 3 Hz. RESULTS:Blade-plate-and-screw fixation resulted in significantly higher mean initial and final stiffness and decreased plastic deformation than did intramedullary rod fixation. In addition, there was an inverse correlation between bone-mineral density and the difference in plastic deformation noted between the specimens of each pair. CONCLUSIONS:Blade-plate fixation is biomechanically superior to intramedullary fixation for tibiotalocalcaneal arthrodesis.

The tibial nerve trunk and its branches were dissected in 20 embalmed cadaver legs and the relative topographic anatomy was defined at 3-cm intervals up to 15 cm proximal to the medial malleolar-calcaneal (MMC) axis. Each nerve branch was found in various locations. The calcaneal nerve was found to descend from medial to posteromedial. It was never found anterolaterally and only rarely laterally. The lateral plantar nerve was found to rotate externally from lateral and posterolateral to lateral and posteromedial as it descends. This nerve was not found medially or anteromedially. The first branch of the lateral plantar nerve was indistinguishable from the trunk of the tibial nerve descending medially to between the lateral plantar and calcaneal nerves. The overall pattern of the medial plantar nerve was an internal rotation from anteromedial (proximal) to anterior (distally). It was not found posteriorly. The flexor hallucis longus motor branch was located an average of 17.9 cm (range, 10-24 cm) proximal to the MMC axis. Preliminary application of these data has facilitated surgical dissection and afforded an understanding of how tibial nerve trunk pathology correlates with clinical manifestations.

Maintaining mobility of the fourth and fifth tarsometatarsal joints has been reported to be important in arthrodesis of the midfoot. A review of the records at a tertiary care center of 23 patients (28 feet) with arthrodesis of these joints and a minimum 2-year follow-up showed that 22 complete midfoot arthrodeses were performed as part of the correction for a neuroarthropathic rocker-bottom deformity. Six arthrodeses of the fourth and fifth metatarsal joints were performed on normosensate feet with painful arthritis involving the lateral joints. Clinical and radiographic fusion occurred in 26 of 28 feet. Comparing average preoperative and postoperative scores, functional incapacity from lateral midfoot pathology decreased (8.4/10 to 2.2/10), overall pain scores improved (5.1/10 to 1.3/10), pain scores in the arthritic subgroup decreased (8.2/10 to 2.4/10), and the modified overall AOFAS midfoot score improved (35/100 to 78/100).

Amputation surgery should be the first step in the rehabilitation of a patient with a nonfunctional limb, rather than the final step in treatment. When faced with a difficult decision regarding lower extremity amputation compared with attempted limb reconstruction, expectations for a reasonable outcome must be determined. After reasonable goals have been set, the surgery should be directed toward interfacing with a prosthetic limb. Current surgical techniques of lower extremity amputation, paying special attention to transosseous versus disarticulation amputation, help to optimize prosthetic limb fitting and functional rehabilitation. With the evolution of end-bearing amputation levels, there is resurgent interest in the bone bridging technique of Johann Ertl and interest in a new pneumatic immediate postoperative prosthetic limb fitting system.

The purposes of the current study were: 1. to analyze the relative fatigue endurance of five different first metatarsal shaft osteotomies (proximal crescentic, proximal chevron, Ludloff, Mau, and Scarf), as performed on sawbone models using the most common fixation techniques (part I); and 2. to compare the two more commonly used techniques (per part I results) in matched-pair cadaver specimens (part II). In part I, the proximal chevron and Mau osteotomies were significantly more stable (P < or = 0.005) than all other osteotomies except the Ludloff. In part II, there was no significant difference in fatigue endurance between the proximal chevron and Ludloff osteotomies.