Bony anatomy of the third metacarpal and relationship with the capitate: a computed tomography study.

PURPOSE: The purpose of this study was to accurately establish the anatomical variability of the third metacarpal, its medullary canal, and the relationship with the capitate in the context of high rates of component loosening still seen in total wrist arthroplasty. METHODS: CT scans of a 100 hands (age: 41 ± 14 years (range: 16-71 years); male/female ratio: 53/47) were studied to establish the detailed anatomy of the third metacarpal and the capitate. RESULTS: Although the shape of the third metacarpal and the angles formed with the capitate were highly variable, the third metacarpal length was longer in males (p < 0.001), the proximal cortical bone was thicker (p < 0.001) and the sagittal metacarpal-capitate axis offset was greater (p = 0.01). A relationship was found between the total length of the metacarpal and the distance to the isthmus from the base (r = 0.63; p < 0.0001) which was unaffected by gender. No age-related relationships were significant. CONCLUSION: The anatomy of the third metacarpal and capitate varies considerably more than has been alluded to in current wrist arthroplasty literature. Differences between males and females can likely be attributed to hand size. The distance of the isthmus from the base can be predicted from the total length of the metacarpal with a standard error of 1.9 mm.

The Effectiveness of a Flexible Locked Intramedullary Nail and an Anatomically Contoured Locked Plate to Treat Clavicular Shaft Fractures: A 1-Year Randomized Control Trial.

BACKGROUND: Displaced and shortened clavicular shaft fractures can be treated operatively with intramedullary or extramedullary fixation. The aim of the present study was to compare the union rates and functional outcomes of displaced and/or shortened clavicular shaft fractures treated with a flexible locked intramedullary nail or with an anatomically contoured locked plate. METHODS: Seventy-two patients with acute displaced and/or shortened clavicular shaft fractures underwent randomly assigned management with either an intramedullary locked nail or an anatomically contoured locked plate. The same surgeon performed all surgical procedures, and all patients underwent identical postoperative treatment regimens. Incision length, surgical time, and union rate were recorded, and the functional outcome of the shoulder was assessed with use of the Disabilities of the Arm, Shoulder and Hand (DASH) and Constant Shoulder (CS) scores. Data were analyzed with use of traditional statistical methods as well as Cohen effect sizes, which were based on the minimal clinical important differences. RESULTS: Thirty-seven patients were managed with an anatomically contoured locked plate, and 35 patients were managed with a Sonoma CRx intramedullary flexible locked nail. There were no differences in general patient characteristics, fracture type, or displacement between treatment groups. The nailing group had significantly better outcomes (p < 0.001) than the locked plating group for surgical time (mean and standard deviation [SD], 45 ± 12 compared with 65 ± 21 minutes, respectively) and incision size (mean and SD, 37 ± 9 compared with 116 ± 18 mm). A union rate of 100% was observed in both groups. DASH scores were similar between groups at 1.5, 3, and 6 months, whereas the nailing group had significantly better DASH scores at 12 months (p = 0.022); however, this difference had only a moderate effect size. Overall, individual variation in DASH and CS scores was substantially higher in the plating group compared with the nailing group. CONCLUSIONS: Both the precontoured locked plate and the flexible locked intramedullary nail effectively treated displaced and/or shortened clavicular shaft fractures. Similar outcomes were achieved at 1.5, 3, and 6 months after surgical intervention, and better DASH scores were found in the nailing group at 12 months. Cohen effect sizes suggested that slightly better outcomes were potentially achieved in the nailing group. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

The treatment of clavicular shaft fractures with an innovative locked intramedullary device.

BACKGROUND: Displaced and shortened clavicular shaft fractures can be treated by intramedullary fixation; however, hardware migration and soft tissue irritation at the insertion site have complicated its use. The aim of this study was to determine whether the new Sonoma CRx intramedullary device (Sonoma Orthopedic Products Inc, Santa Rosa, CA, USA) could be used successfully to treat displaced and shortened clavicular shaft fractures and restore the functional capacity of shoulder without the development of secondary complications. METHODS: Displaced and shortened clavicular shaft fractures in 47 consecutive patients were treated with the CRx device. Incision size was captured during the surgical procedure. The union rate was evaluated postoperatively. Shoulder function was assessed by Disabilities of the Arm, Shoulder and Hand (DASH) score, the Constant Shoulder Score, and a range of motion score. Patients were assessed after 3 to 6 months (group I), 6 to 9 months (group II), or 9 to 12 months (group III) postoperatively. RESULTS: Union was achieved in all patients at the time of review, without any incidence of hardware migration. Postoperative complications developed in 3 patients, comprising infection in 1 and hardware failure in 2. No differences among the groups were found for the DASH score (P = .33), Constant Shoulder Score (P = .38), and range of motion score (P = .96). The DASH, Constant Shoulder, and range of motion scores were similar to other successful treatment options, such as plating. CONCLUSION: The Sonoma CRx is a good alternative device to treat displaced and shortened clavicular shaft fractures and restore the functional capacity of the shoulder. Future research should focus on when nailing and plating should be used to treat clavicular shaft fractures most optimally.