Patient specific instrumentation for corrective osteotomy in case of posttraumatic cubitus varus in children

Malunion in cubitus varus most often results from inadequate supracondylar fracture reduction or from secondary displacement. Treatment of cubitus varus needs an accurate preoperative planning to obtain a good functional and esthetical outcome. Planning based on conventional radiology is source of inaccuracy and clinical results are variable. Developments of computer-assisted orthopaedic surgery (CAOS) and of patient specific instruments (PSI) have made accurate three dimensional (3D) preoperative simulation possible. This original technique based on 3D-osteotomy planning and using PSI was developed to correct cubitus varus deformity in the three dimensions. A 3D-model of the deformity was created based on a CT-scan of the distal humerus. Ideal correction was calculated by software and a PSI was designed. The PSI was used to guide the saw blade on the deformed bone. After resection of a wedge fragment, osteosynthesis was performed using two crossed K-wires. Elbow radiographs were performed at least six months after surgery. At the latest follow-up, the correction of cubitus varus obtained was satisfying in the five cases of our series and all the patients had pain free elbow mobility. Ulnar nerve palsy complicated the evolution in one patient, which fully recovered within 6 months. Advantages of this technique include a decreased operating time and a smaller surgical incision. More-over, results showed increased correction accuracy without the need of fluoroscopy during the osteotomy procedure. These benefits are counterbalanced by the need of a preoperative CT-scan of the distal humerus and the additional cost for the PSI.