RESUMO
This case report documents a rare inversion of a closed metacarpal head fracture in the setting of polytrauma. Although rare, hemispherical articular bones can fracture and rotate 180°. Because of the symmetry of the bone and the rarity of an inverted, metacarpal head fracture, a delay in diagnosis and subsequent treatment can occur, which can lead to a poor outcome. This is particularly true in the setting of polytrauma. A 38-year-old male, polytrauma patient presented to the emergency department (ED) after falling off a bridge and being struck by an oncoming vehicle. He presented with multiple surgical fractures of the upper and lower extremities as well as his pelvis. Three days after he was brought to the ED, x-rays were performed of his painful left hand, which revealed an extra-articular third metacarpal head fracture, for which he underwent open reduction of the closed fracture. Both collateral ligaments were intact and the head fragment had inverted within the constraints of these ligaments. Some of the ligament and capsular tissue remained attached to the head fragment along the radial and ulnar margins but was otherwise entirely covered with cartilage. The reduction maneuver was difficult but after the reduction was achieved, the fracture appeared stable and no internal fixation was used. Post reduction, the injury was splinted for 2 weeks and then early motion was allowed. The fracture has since healed, and the patient has attained near-full function of the finger and joint.
RESUMO
PURPOSE: The purpose of this study was to compare the tensile strength of hamstring grafts of varying combined pull-through diameters within the clinically relevant range of 6 to 9 mm. METHODS: We tested 44 non-irradiated allograft hamstring grafts (11 per group). Combined looped semitendinosus and gracilis grafts were allocated to the 6-, 7-, 8-, or 9-mm group based on the smallest-diameter lumen that the graft could be "pulled through" using a surgical sizing instrument. Testing was performed on an Instron materials testing machine (Instron, Norwood, MA). Samples were secured with cryoclamps, prestressed, and pulled to failure at a rate of 10% gauge length per second. RESULTS: The mean load to failure was 2,359 ± 474 N, 3,263 ± 677 N, 3,908 ± 556 N, and 4,360 ± 606 N for the 6-, 7-, 8-, and 9-mm grafts, respectively. Minimum failure loads were as low as 1,567 N, 2,288 N, 2,874 N, and 3,720 N for each group, respectively. There were statistically significant differences between the 6- and 7-mm, 6- and 8-mm, 6- and 9-mm, and 7- and 9-mm groups (P = .01). CONCLUSIONS: Statistically different increasing tensile strength was seen as graft diameter increased. Significant variability exists in the strength of multi-stranded hamstring allografts within the diameter range of 6 to 9 mm that often falls well below the commonly accepted value of 4,000 N for a hamstring graft. CLINICAL RELEVANCE: Recent evidence suggests a higher early failure rate of hamstring autografts in subsets of patients with graft diameters of 8 mm or less. This study may increase awareness that hamstring grafts may not be nearly as strong as previously appreciated and that increasing tendon diameters by 1 to 2 mm may dramatically affect graft strength. These data may be helpful in preoperative discussions regarding variable hamstring size, strength, and potential intraoperative augmentation options.
