Proximal focal humeral deficiency in a large breed dog

Bilateral shoulder arthrodesis in a Pekinese using three-dimensional printed patient-specific osteotomy and reduction guides

OBJECTIVE

To report the use of computer-aided design software for virtual surgical planning and design of three-dimensional printed patient-specific osteotomy and reduction guides for facilitation of bilateral shoulder arthrodesis in a dog.

METHODS

A three-year-old male entire Pekinese was presented unable to walk due to bilateral severe medial shoulder instability. Computed tomographic data was processed to yield three-dimensional mesh representations of the humeri and scapulae which could be manipulated in computer-aided design software. Key virtual surgical planning steps included joint realignment, osteotomies of the glenoid and humeral head, and reduction. Virtual osteotomy and reduction guides were designed, three-dimensionally printed, and used intra-operatively.

RESULTS

Appropriate alignment, reduction and fixation of the humeri and scapulae were achieved bilaterally. The patient regained the ability to walk unassisted after two weeks and was subsequently able to exercise normally without lameness.

CLINICAL SIGNIFICANCE

Patient-specific, three-dimensional printed osteotomy and reduction guides facilitated accurate bilateral shoulder arthrodeses.

Shoulder joint hemiarthroplasty for treatment of a severe osteochondritis dissecans lesion in a dog

INTRODUCTION

Partial resurfacing of the humeral head has been reported in humans to treat humeral osteochondritis dissecans. The aim is to describe a custom-made humeral resurfacing prosthesis for treatment of severe humeral head osteochondritis disse-cans in a dog.

CASE REPORT

A seven-month-old female entire St. Bernard dog was presented with a 10 week history of severe left thoracic limb lameness. Radiography, arthroscopy and magnetic resonance imaging confirmed an extensive osteochondritis dissecans lesion affecting the caudal, medial and central regions of the humeral head. A prosthesis designed from computed tomography (CT) images was manufactured in polished stainless steel alloy with a hydroxyapatite coated base and central finned humeral stem for cementless insertion. A standard caudal approach to the shoulder was used to place the prosthesis following reaming of the caudal humeral head.

RESULTS

Radiography and CT imaging revealed appropriate topographical placement on the humerus. Force plate analysis demonstrated initial reduction in ground reaction force at six weeks, followed by gradual improvement at three months. There was no radiographic evidence of implant loosening and the range of shoulder joint motion was comparable to the contralateral joint at three months; these findings were maintained to final follow-up at 24 months.

CLINICAL SIGNIFICANCE

Placement of a humeral head resurfacing prosthesis was an effective technique for the management of severe osteochondritis dissecans-related shoulder lameness. To the authors' knowledge, this is the first report of the clinical use of shoulder hemiarthroplasty in a dog.