Distal femoral physeal fixation: are smooth pins really safe?

BACKGROUND: Distal femoral physeal fractures have a high incidence of physeal arrest. Several factors have been postulated to contribute to this high incidence, including fracture type, displacement, the undulating nature of the physis, and fracture reduction/fixation. The purpose of this study was to determine whether the position of percutaneous smooth pins across the physis contributes to physeal bar formation. METHODS: The previously validated New Zealand white rabbit model was used. Power analysis determined that 30 animals were required. All animals had a constant 0.045 smooth Kirschner (K) wire placed under fluoroscopic guidance from the distal lateral femur across the physis centrally. A second 0.045 K-wire was placed in a cross-pin configuration from the medial side in one of 2 positions: zone 1--crossing the physis centrally or zone 2--crossing the physis peripherally. Pins were removed after 4 weeks and micro computed tomography was performed at 8 weeks to assess for physeal bar formation. Histologic analysis was performed to confirm bar formation. RESULTS: Two physeal bars (7%) were seen after removal of the constant (lateral pin). The peripheral pin resulted in bar formation in 2 animals (13%) and the central pin in 1 animal (7%). A χ² test was performed; there was no statistically significant difference between zones in terms of bar formation (P=0.5428). CONCLUSIONS: Injury to the growth plate after distal femoral fracture may be unavoidable. Treatment is aimed to minimize further injury to the physis. Cross-pinning with smooth K-wires results in a low rate of physeal injury. Pins that cross the physis both centrally and peripherally appear to have the same risk for physeal bar formation. CLINICAL RELEVANCE: This study reveals that physeal bar formation can be seen with smaller than previously reported cross-sectional damage to the distal femoral physis. This study highlights the need to carefully select and perform fixation of the distal femoral physis with as little additional trauma to the physis as possible.

Cloud-based preoperative planning for total hip arthroplasty: a study of accuracy, efficiency, and compliance.

As digital radiography becomes more prevalent, several systems for digital preoperative planning have become available. The purpose of this study was to evaluate the accuracy and efficiency of an inexpensive, cloud-based digital templating system, which is comparable with acetate templating. However, cloud-based templating is substantially faster and more convenient than acetate templating or locally installed software. Although this is a practical solution for this particular medical application, regulatory changes are necessary before the tremendous advantages of cloud-based storage and computing can be realized in medical research and clinical practice.

Biomechanical properties of fixed-angle volar distal radius plates under dynamic loading.

PURPOSE: To evaluate and compare the biomechanical properties of 8 different locked fixed-angle volar distal radius plates under conditions designed to reflect forces seen in early fracture healing and postoperative rehabilitation. METHODS: We evaluated the Acumed Acu-Loc (Acumed, Hillsboro, OR), Hand Innovations DVR (Hand Innovations, Miami, FL), SBi SCS volar distal radial plate (Small Bone Innovations, Morrisville, PA), Synthes volar distal radius plate and EA extra-articular volar distal radius plate (Synthes, Paoli, PA), Stryker Matrix-SmartLock (Stryker Leibinger, Kalamazoo, MI), Wright Medical Technology Locon VLS (Wright Medical Technology, Arlington, TN), and Zimmer periarticular distal radius locking plate (Zimmer, Warsaw, IN). After affixing each plate to a synthetic corticocancellous radius, we created a standardized dorsal wedge osteotomy. Each construct had cyclic loading of 100 N, 200 N, and 300 N for a total of 6000 cycles. Outcomes, including load deformation curves, displacement, and ultimate yield strengths, were collected for each construct. RESULTS: The Wright plate was significantly stiffer at the 100 N load than the Zimmer plate and was stiffer at the 300 N load than 4 other plates. The Zimmer and Hand Innovations plates had the highest yield strengths and significantly higher yield strengths than the Wright, SBi, Stryker, and Synthes EA plates. CONCLUSIONS: Given the biomechanical properties of the plates tested, in light of the loads transmitted across the native wrist, all plate constructs met the anticipated demands. It seems clear that fracture configuration, screw placement, cost, and surgeon familiarity with instrumentation should take priority in selecting a plating system for distal radius fracture treatment. CLINICAL RELEVANCE: This study provides further information to surgeons regarding the relative strengths of different plate options for the treatment of distal radius fractures.

Sea urchin injuries to the hand: a case report and review of the literature.

Sea urchin injuries to the hand are uncommon. A variety of home remedies can be found on the internet and other sources for dealing with this problem in the acute setting. Many long term complications such as granulomas, arthritis, and tenosynovitis can result from a neglected sea urchin injury. We report an unusual case of a patient with a remote sea urchin injury who presented with ulnar digital nerve paresthesias. A traumatic neuroma was found on surgical exploration. We review the literature on injuries to the hand caused by sea urchins and their management. Management of sea urchin injuries to the hand with retained spines requires surgical debridement in order to prevent significant long term complications including stiffness, tenosynovitis, granulomas, and arthritis.