Fractures of the Proximal Phalanx

Ex vivo comparison of standing and recumbent repair of incomplete parasagittal fractures of the first phalanx in horses

“…Nevertheless, implants are best tightened with the leg unloaded to counteract the potential distraction with weight bearing. 9,11,12 While our results provide evidence of a clear absence of effect and that limb elevation is not required, aspects of study power and the closer clinical context must be considered in light of negative findings. In an ovine osteotomy model, increasing fracture gap width from 1 to 2 mm, and keeping interfragmentary bone strain constant resulted in a 60% reduction of bone formation, indentation stiffness, and tensile strength at the interfragmentary gap 9 weeks post surgery.…”

“…According to standard surgical technique, proximal implants should be positioned between 0.5 and 0.8 cm distal to the sagittal groove of P1 either adjacent to the dorsal border of the extensor branch of the suspensory ligament (singlescrew technique) or one dorsal and one palmar to the branch (two-screw technique). 11 After review of screw position in an earlier project, 10 it became apparent that, had proximopalmar 4.5-mm cortical bone screws been aligned orthogonal to the fracture plane, threads would have exited the palmar cortex of P1 in three of 14 fracture simulations (R. Labens, unpublished data, Jan 2020). Implant position illustrated in a recent clinical report (Findley et al 9 Figure 3) provides evidence that this risk must be considered in standing triangular repairs.…”

“…Because of this natural potential for fracture gap distraction during axial loading, perceived optimal screw insertion torques may be reached more rapidly and result in less lag compression when repairs are performed with horses standing rather than in recumbency. This may be of particular relevance with use of only one implant subjacent to the MCPJ and may validate recommendations to unload limbs for screw tightening and optimization of axial compression during standing repair 9,11,12 …”

“…This may be of particular relevance with use of only one implant subjacent to the MCPJ and may validate recommendations to unload limbs for screw tightening and optimization of axial compression during standing repair. 9,11,12 Surgical landmarks such as the MCPJ, sagittal groove, palmar eminence of P1, and the extensor branches of the third interosseous muscle (suspensory ligament) guide correct screw positioning in repair of parasagittal P1 fractures. In the context of standing vs recumbent fracture repair, it is unknown to what level axial loading and extension of the MCPJ affects the position of an important landmark-the extensor branches-and, consequently, implant placement.…”

Influence of a purpose‐built frame on the accuracy of computer‐assisted orthopedic surgery of equine extremities

“…At first glance, the high purchase costs for the equipment may seem the most striking explanation. However, the 3D‐imaging unit usually is the most expensive part of the investment in a CAOS‐ready infrastructure, and many larger equine referral centers already have navigation‐compatible 3D‐imaging devices at their disposal, and many more are investing in CT units specifically for intraoperative and orthopedic imaging 37,38 . Thus, other factors must be taken into consideration.…”