The stepped hybrid plate for carpal panarthrodesis - Part I: relationship between plate and bone surfaces.

In the 1990s, the AO (Arbeitsgemeinschaft für Osteosynthesefragen) Hand Study Group developed several anatomically bent plates (standard and short) for wrist panarthrodesis in humans. However, only straight plates have been used for carpal panarthrodesis (CP) in animals to date. The primary purpose of this study was to determine if precontoured plates are more anatomical for CP in dogs. Measurement of several of the bones that are implicated in CP, as well as the relationship between their surfaces and the surface of a straight plate, were performed in a radiographic and computed tomographic cadaveric study. Axial and transverse measurements taken at different levels of the metacarpal bones 2, 3 and 4 were also included. The second objective of this study was to develop a more anatomical CP plate according to the results obtained. The measurements and images obtained in this study show that, as in human orthopaedics, bent or stepped plates are more anatomically correct than straight plates for CP in dogs.

The stepped hybrid plate for carpal panarthrodesis - Part II: a multicentre study of 52 arthrodeses.

Fifty-two carpal panarthrodeses (CP) were carried out in 44 dogs (eight bilateral), in a multicentre study using a single (n = 47) or double (n = 5) stepped hybrid CP plate. Of these 44 cases, 39 were between 20-55 kg in bodyweight , 26 were males , and the carpometacarpal was the most common joint involved. Falling and other impact trauma were the most common aetiology. Pain of unknown origin, carpal luxation, chronic accessory carpal bone fracture, distal comminuted intra-articular radial fracture, bone tumour, degenerative joint disease, canine erosive idiopathic polyarthritis, avascular necrosis of the radial carpal bone and fractures of several metacarpal bones were some of the pathologies reported. Fracture of the third metacarpal bone during screw insertion was the only intrasurgical complication. Malpositioning of the plate or screws and over-tightened screws were technical errors observed in seven of the procedures. The radial carpal bone was not fixed with a screw in two cases due to bone deformity. Concurrent plate breakage and bending in the same patient operated on bilaterally was observed during the follow-up period, which represented a major complication rate of 3.8% for all procedures. Minor complications were: low grade infection, lick granuloma, digit hyperextension, screw loosening or failure, incomplete fusion of some joints and a fracture of the third metacarpal bone at the distal screw hole of the plate; which represented a rate of 44.2% on all procedures. Complete carpal healing was observed radiographically in 94.2% of all procedures. Limb function was excellent to good, and all of the owners, except for one, were satisfied with the procedure.

Interlocking nail treatment of long-bone fractures in cats: 33 cases (1995-2004).

A retrospective study between 1995 and 2004 of fracture repair in cats (n = 46) using interlocking nails (ILN) was made. Only the cases in which clinical and radiographic examination of bone healing were available are included. Five humeral and twenty eight femoral fractures were reviewed. Multiple-hole interlocking nails (MH-ILN) were used in 22 fractures, with the four-hole model (FH-ILN) in the remaining cases. In three of the cases, the FH-ILN was transformed to a three-hole model by cutting the nail between the two most distal holes. The average length of humeral ILN was 78.8 mm, and the femoral ILN was 97.2 mm. Static fixation was performed in 27 cases, with dynamic fixation in the remaining. The medullary canal filling was 100% in both radiographic views in 16 cases. Intra-operative complications were encountered in two cases. A total number of 76 screws were inserted, with 5.26% of them being malpositioned. Malunion, in a deformed femur, and partial unscrewing of one screw were the only radiographic complications observed at the time of follow-up. The clinical outcome, as well as fracture healing, were excellent in all of the cases. The results of this study indicate that the 4.0 and 5.0 mm MH-ILN and FH-ILN can be used to repair simple or comminuted humeral and femoral fractures in cats.