Level of Sagittal Plane Fit of Plates on the Radial Shaft: A Cadaveric Study Comparing Precontoured and Straight Titanium Plates

Background: During radial shaft fracture fixation, it is important to contour the plate appropriately to restore the radial bow in order to maintain normal forearm mechanics and motion. The aim of this study was to investigate the fit of precontoured radial shaft plates versus surgeon-contoured plates. Methods: Six 10-hole Acumed® precontoured volar and dorsolateral radius plates and twelve 10-hole Synthes straight titanium 3.5 mm LC-DCP plates were drilled with arrays of 1.5 mm diameter holes to permit measurement of the plate distance off bone. Plates were applied to 6 cadaver radii and secured with a screw on each end. Three plate conditions were tested: precontoured plates, precontoured plates with further surgeon contouring, and straight plates with surgeon contouring. Surgeon contouring time for each plate was recorded. Each plate was divided into 3 equal regions, and the average distance gaps for each region and the entire plate were calculated. Results: For the volar side, precontoured plates had a larger total gap compared to that plate with additional surgeon contouring (1.4 mm difference) and the straight surgeon-contoured plates (1.2 mm difference). On the dorsal side, there was no difference in fit between the 3 plate conditions at any location. No differences were found in plate contouring times. Conclusions: The precontoured dorsal plate fit was as good as the surgeon-contoured plates indicating this plate could potentially be used in fracture surgery without further bending. The precontoured volar plate was under-contoured, on average, and would likely require further bending to restore the radial bow.

Outcomes of Flexor Pollicis Longus Reconstruction for Volar Plate Related Ruptures

Aim A rare complication following volar plate fixation of a distal radius fracture is flexor pollicis longus (FPL) rupture. This study aims primarily to analyze the radiographic features and secondly to report the patient-reported outcomes of FPL reconstruction after volar plate fixation. Methods Ten patients were retrospectively identified and contacted for follow-up. Seven patients participated in the study and completed the numeric rating scale (NRS) for pain, patient-reported outcome measurement information system—upper extremity (PROMIS-UE), and quick disability of arm, shoulder, and hand (QuickDASH) questionnaires at a median of 3.4 years following FPL reconstruction. Soong grade was determined on preoperative radiographs. Results Six patients were classified as Soong grade 1 and two patients had a screw or wire protruding volarly. The median time to tendon rupture was 21.6 months. At final follow-up, the median NRS pain score was 0 (range: 0–7); the median PROMIS-UE score was 47.1 (range: 25.9–61); and the median QuickDASH-score was 12.5 (range: 4.5–75). Conclusions The outcome of FPL reconstruction after volar plate fixation is highly variable. All ruptures in our cohort occurred in patients with plate positioning classified as Soong grade 1 and occurred at up to 3 years following distal radius fixation.

Effect of a Flexor Digitorum Superficialis Hemitenodesis on Reducing Volar Plate Strains for Swan Neck Deformities

Background Flexor digitorum superficialis (FDS) hemitenodesis is a common procedure to treat swan neck deformity (SND). We hypothesize that this surgical technique is a biomechanically effective way to reduce strain in the volar plate at the proximal interphalangeal joint (PIPJ). Methods Fifteen digits from 5 cadaveric specimens were tested using a novel in vitro active finger motion simulator under 4 finger conditions: intact, SND, FDS hemitenodesis, and FDS hemitenodesis with distal interphalangeal (DIP) joint fusion. Tensile loads in FDS and flexor digitorum profundus (FDP) and joint ranges of motion were measured by electromagnetic tracking. In addition, strain gauges were inserted under the volar plate to measure strain during PIPJ hyperextension. Results were analyzed using 1-way repeated-measures analysis of variance tests. Results The SND condition increased volar plate strain by 176% ± 25% ( P < .001) compared with the intact condition. The FDS hemitenodesis repair relieved more than 50% of the SND strain, restoring it to within no statistical difference from intact. The DIP fusion further reduced strain with no further statistical significance. At full flexion, FDS and FDP tendon loads diverged as a function of the test condition ( P < .001). With the FDS hemitenodesis, the FDP load increased by 2.1 ± 1.5 N from the SND condition ( P < .001), whereas the FDS load decreased by 1.3 ± 1.3 N ( P = .012). Conclusion The FDS hemitenodesis repair restored strains to within 3.0 milli-strain of the intact condition with no significant difference. Application of DIP fusion did not further protect the PIPJ from increased hyperextension and further exacerbated the imbalance of flexor tendon loads.