Extended FCR Approach: Contact Pressures Between FPL and Volar Plate
Christopher M Jones, MD; Roshan Melvani, MD; Kenneth R Means Jr, MD
Union Memorial Hospital - Orthopaedic Hand Surgery, The Curtis National Hand Center, Baltimore, MD
Fixed-angle volar plating is an effective technique for distal radius fracture fixation as the volar approach is less disruptive to the tendons than the dorsal approach. Studies have shown that volar plates placed distal to the watershed line have the potential to impinge on traversing flexor tendons. One cadaveric study attempted to quantify contact pressure between a volar plate and the FPL tendon. Despite debates about plate application relative to the watershed line and its effect on the flexor tendons, little evidence exists to suggest an alternative approach. Some controversy exists with regard to whether it is necessary to perform the more extensive FCR approach in every setting.
This biomechanical study uses 10 matched cadaver pairs to account for differences in bone and tendon quality, age, and gender. Native forearm anatomy was preserved to more accurately assess a true post-operative scenario. A standard FCR approach was performed in one arm; an extended FCR approach (EFCR) was performed in the matched arm. A distal radius volar locking plate was fixated at the watershed line, a Techscan pressure sensor was placed between the plate and the flexor tendons, and wounds were closed in standard fashion. The flexor and extensor tendons were sutured in their respective anatomic position. The specimen was cyclically loaded for 4,000 cycles on a materials testing machine to evaluate and quantify pressure between the plate and the FPL tendons.
We found that the ulnar sensor demonstrated higher pressures in the EFCR approach at low cycles but once 1000 cycles were reached pressures were lower in the extended approach and continued through 4000 cycles. The radial sensor was found to have similar findings, with higher pressures in EFCR approach up to 1000 cycles but lower pressures compared to standard approach after 2000 cycles. In addition, gross findings noted no tendon ruptures and overall unchanged tendon appearance compared to pre-loading.
No statistically significant difference noted between the two approaches. Our findings do suggest that at higher cycles the contact pressures in the EFCR approach are lower than the standard approach. This may suggest that the EFCR has benefit in reducing the rate of flexor tendon rupture after volar plating of the distal radius.
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