Computer-assisted surgery for placing toggle constructs across the coxofemoral joints of small equids using a minimally invasive approach-A proof-of-concept cadaveric study.

Abstract

To develop a minimally invasive technique for placing a toggle construct across the coxofemoral joint of small equids using computer-assisted surgery. Experimental cadaveric study. Three pilot specimens: One donkey, one Shetland pony and one Warmblood foal. Six main study specimens: Three Shetland ponies, one American Miniature Horse, one Warmblood foal and one donkey. Experimental surgeries were performed on both coxofemoral joints of each cadaver. Using a minimally invasive surgical approach, 5.5 mm bone canals were drilled through the femur and acetabulum, traversing the coxofemoral joint. Intraoperative guidance was provided by a cone-beam computed tomography (CBCT)-coupled surgical navigation system. A toggle construct was introduced through the bone canals. Surgical accuracy aberrations (SAA) were measured at the femoral entry and exit points and at the acetabular entry point on merged pre- and postoperative CBCT scans. The coxofemoral joint was assessed for articular cartilage damage by gross dissection. A toggle construct was placed across all 18 coxofemoral joints. The overall median SAA in the main study was 2.8 mm (range: 0.4-8.0 mm). No cartilage damage was found in the cadaveric specimens of the main study. The described technique allowed for the placement of a toggle construct across the coxofemoral joint of small equid cadaveric specimens without prior coxofemoral luxation. This technique may serve as an option for surgical stabilization of coxofemoral joints in small equids. Further biomechanical investigations are required to assess optimal implant positioning and toggle constructs.