Introduction: A 10 month old black and white Border Collie was referred from Southern NSW with bilateral forelimb lameness and significant muscle wastage.
Examination: Significant pain was present in both shoulders on complete hyperextension. Muscle atrophy over the scapula spine was evident worse on the LHS. No long bone pain suggestive of panosteitis was present. Bothe elbows had no effusion underneath the anconeus muscle laterally.
Diagnostic Imaging: Plain radiographs and CT scan of the scapulohumeral joints were obtained.
Flattening of the caudomedial humeral head was observed. Subjacent underlying subchondral bone sclerosis was present. Distinct OCD flap formation was present with subtle fragmentation.
Client Discussion: We discussed arthroscopic removal of OCD flaps with the clients. Complications can include seroma formation, ongoing limping from cartilage loss and arthrosis, infection etc. Despite this prognosis is very good with most cases recovering athletic function well.
Operative Management: The patient was premedicated with acepromazine and methadone before being induced for anaesthesia with propofol and maintained on isoflurane. He was placed on IV fluids and administered a single dose of cefazolin. Intra-operative patient monitoring included SpO2, ETCO2, BP, ECG, HR and Temp. He was placed under a Bair Hugger and on a circulating warm water blanket.
Shoulder prep was performed before shoulder arthroscopy. We used a Strker 1.9mm 30 degree forward HD autoclavable scope. Hand pump fluid pressure was judiciously employed. The large flaps were instrumented and removed before osteostixis and gentle edge curettage. Two sutures were used for closure. Recovery icepacking whilst watching core body temperature was used. A wound dressing was applied.
Outcome: The patient was initially managed with regular icepacking and strict confinement for 3 weeks. He was medicated with carprofen and tramadol. He then began short regular leash walks. Running activity was re-commenced 6 weeks postoperatively. At the 6 month mark he had no appreciable lameness. His regular veterinarian began pentosan polysulfate injection courses twice yearly.
Discussion: Osteochonditis dissecans is a common presentation in Border Collies, Kelpies, Golden Retrievers, Mountain Breeds and giant breeds in general. Presentation typically occurs between 5 and 10 months of age is is normally a significant lameness. Even in bilateral cases the presentation is usually lateralized. Muscle atrophy is the next most common finding followed by pain on shoulder hyperextension which is interestingly not always present. Despite research (fits and starts) the underlying aetiology/pathogenesis is poorly understood. In our practice Border Collies and Kelpies account for over 75% of the presenting breeds. Whilst concurrent elbow dysplasia is occasionally seen it is rare.
Surgical removal and subchondral bone limited stimulation results in satisfactory outcomes with return to a reasonable level of athleticism in most cases. Degrees of arthrosis following the surgery are proportionately less than those with elbow dysplasia despite the large size of the lesions.
Arthroscopically managed cases return to walking with reduced postoperative discomfort quickly. The scope allows far better joint visualization than arthrotomy and has a much lower incidence of seroma formation which can be substantial in arthrotomy cases even with precise attention to closure detail.
