Clinical tips: retrograde drilling of talar osteochondral defects.

Contemporary methods of bone grafting osteochondral defects, in which the remaining overlying cartilage is relatively well preserved, have inherent problems. The bony defects are often saucer-shaped and the cylindrical graft may not fill the void, leaving areas of cartilage with no underlying scaffold and obviating early weight bearing. Furthermore, to obtain a proper fill of the defect, tamping of the graft can cause excessive pressure and disruption of the overlying cartilage. In an effort to address these concerns, the authors propose the use of a biological viscous paste of calcium sulfate that hardens within 5 minutes when injected in a retrograde fashion into the talus. This confers a mechanical advantage of complete cystic fill of the cyst which allows early weight bearing. Calcium sulfate acts as an osteoconductive material that incorporates into host bone within 8 weeks. Donor site morbidity is eliminated using this system.

The frequency of digital artery resection in Morton interdigital neurectomy.

BACKGROUND: Operative strategies used in resecting the digital nerve in Morton neuroma emphasize retaining the digital artery. Concern over inadvertent resection of the digital vessel has prompted many surgeons to avoid adjacent interdigital neurectomies when more than one nerve is affected. METHODS: The current study examined 674 consecutive pathologic specimens obtained after neurectomy. RESULTS: The digital vessel was identified along with the resected nerve in 39% of specimens. No adverse effect was recorded from these arterial resections. CONCLUSION: Extensive collateralization of digital vessels is hypothesized to account for the lack of adverse sequelae.

Observations on the fibrous retinacula of the heel pad.

BACKGROUND: The original purpose of the study was to clarify whether or not there is continuity of the Achilles tendon and the plantar fascia. Those findings have been previously published. In the course of that study, observations of the anatomy of the retinacular tethers of the heel pad were made. These observations included the discovery of the medial calcaneal retinaculum. METHODS: Ten adult cadaver feet were dissected. A longitudinal midline incision was made along the Achilles tendon and on the plantar surface of the foot. The heel pad was incised and the skin and heel pad were reflected side-to-side to reveal the calcaneal tuberosity. In this way the retinacular tethers of the heel pad could be seen. RESULTS: Two types of retinacular fibers were observed. Abundant small retinacula were seen coming off the plantar fascia and calcaneal tuberosity. Less abundant larger retinacula originated from the calcaneus only. Both types anchored the heel pad by branching into the fibrous stroma of the heel pad. In nine of 10 feet, a much larger retinacular structure was the principle tether of the heel pad to the medial process of the calcaneal tuberosity. We named this the medial calcaneal retinaculum. CONCLUSIONS: The heel pad is anchored by retinacula that vary in number, location, and size. The most consistent and significant tether of the heel pad appears to be the medial calcaneal retinaculum. CLINICAL RELEVANCE: Dislocation of the fat pad of the heel is a relatively rare but potentially devastating injury. An understanding of the anatomical anchoring of the heel pad and its mechanical function can lead to a surgical procedure to restore stability to the heel pad.

An analysis of talar surface area occupied by screw fixation in ankle fusions.

BACKGROUND: Ankle arthrodesis remains the benchmark of treatment for end-stage arthrosis of the ankle joint. Despite that, the incidence of nonunion can be as high as 15%. Various strategies have been used to reduce the incidence of nonunion, including multiple compression screws and larger diameter screws to improve mechanical stability and compression. The space occupied by an increasing amount of hardware across a finite surface area available for fusion has prompted concern that this strategy may be counterproductive and may reduce the biological potential of the construct. The purpose of this study was to look at 40 anatomic sawbone specimens of the ankle to determine the amount of talar surface contact area used by the screw fixation during arthrodesis. METHODS: Four groups were created to examine different techniques for arthrodesis. Simulated ankle arthrodeses were done using two- or three-screw fixation with 6.5-mm and 7.3-mm screws. Hardware was subsequently removed and the surface area used by the passing screws was measured. Total surface areas were calculated for each of the 40 specimens. RESULTS: The maximal surface area of the talus occupied by screws occurred when using three 7.3-mm screws. This configuration used 16% of the possible talar surface area available for arthrodesis. CONCLUSION: The use of additional screw fixation when performing an ankle arthrodesis does not sacrifice a major amount of the tibiotalar contact area and will most likely not affect the biologic environment needed to obtain fusion.