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Veterinary
Surgery
In OKC Near Edmond 405-751-3920 |
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Canine Developmental/Juvenile Orthopedic DisordersThe incidence of orthopedic disorders for all ages of dog has been reported to be 24%, with 70% of those involving the appendicular skeleton. 20 % of all patients presenting with an orthopedic disease are less than 1 year old. Approximately 50 % of those young dogs have traumatic injuries. 9 % of all young patients presenting with an orthopedic problem are diagnosed with Osteochondrosis (OC/OCD). This presentation will focus on developmental orthopedic disorders including OCD, hip dysplasia, hypertrophic osteodystrophy, Legg-Calve-Perthes disease, elbow incongruity, panosteitis, and traumatic orthopedic injuries. 1.Osteochrondrosis (OC/OCD) A.OC is disturbance in the process of endochondral ossification. Endochondral ossification is the process that allows for growth of the long bones and the development of the ends of the bone including the articular surface. OC results in an area or areas of thickened cartilage that may spontaneously heal, cause bone growth abnormalities, or joint disease. Joint disease results when a thickened area of cartilage fissures or fractures. Joint fluid communicating with subchondral bone, pressure on subchondral bone, cartilage break down products and shear forces on a resulting cartilage flap are suggested to be the causes of joint inflammation and pain. The inciting cause of OC is most likely a disruption of blood flow in the articular-epiphyseal cartilage complex causing areas of cartilage necrosis. Trauma, hereditary factors, rapid growth, nutritional factors and ischemia all seem to contribute to the pathogenesis of OC/OCD. Common locations for OCD include the caudal central humeral head, medial portion of the humeral condyle, lateral and medial femoral condyle and the plantar aspect of the medial trochlear ridge and dorsal aspect of the lateral trochlear ridge. OCD has been reported in the spine, scapular glenoid, femoral head, and dorsal acetabular rim. B.Humeral head OCD 1.The incidence of humeral head OCD is 0.22% for male dogs and 0.09% for female dogs. 75 % of OCD cases reported affect the humeral head. 2.Males are affected more than females in a ratio of about 2.24=1. 3.Usually seen in large breeds such as the Labrador, Rottweiler, and Golden Retriever. The Doberman pinscher, Collie, and Siberian husky are at low risk for shoulder OCD. 4.Lameness most commonly noted between 5-6 months of age. Only 17% of dogs with OCD are presented for evaluation after 1 year of age. 5.Clinical Signs a.Weight-bearing lameness b.Short stride c.Pain on extension and flexion of shoulder d.Mild atrophy of supraspinatus, infraspinatus and deltoideus with resulting prominence of the scapular spine. 6.Diagnosis a.Mediolateral and craniocaudal radiographic projections of the shoulder in an anesthetized patient are usually diagnostic. The affected limb is down and firm traction is placed on it to pull the shoulder cranially and ventrally to avoid superimposition of the neck and thorax. The opposite limb is pulled caudally to avoid any overlap of the opposite thoracic limb. b.OCD is confirmed by the presence of flat radiolucent area on the caudal humeral head. c.Arthroscopy or arthrography can be helpful to diagnose equivocal eases. d.Joint mice in the bicipital tendon sheath were noted in 8 of 76 cases having arthrography. These are difficult to see on plain radiographs and may be responsible for a poor or incomplete response to treatment. e.Always x-ray both shoulders. Radiographic OC lesions are present in about 50 % of cases. Only 21 % of dogs with lesions in both legs are lame in both legs, but 50 % require surgery on both shoulders to eventually resolve OCD. I recommend arthroscopy or surgery on an opposite leg with radiographic OC during the same anesthetic episode used for the lame leg to minimize recovery time, cost to the owner and the necessity of a second anesthesia/surgery. 7.Treatment a.Conservative Management: weight control, activity restriction, NSAIDS and slow-controlled leash walks. I only recommend conservative treatment on dogs less than 9 months old with radiographic OC and no clinical signs of shoulder pain. There may be a lesion that is not separated from the bone that will heal with time. Surgery is recommended if you are certain there is an actual OCD lesion (flap) in the joint. b.Surgery 7.Open Surgery a.I prefer the caudal muscle separation approach. b.Remove the flap, bevel edges of the defect perpendicular to the subchondral bone, forage lesion, thoroughly flush the joint and close the joint capsule. 8.Arthroscopy a.Remove flap b.Microfracture bed or perform abrasion arthroplasty. c.Thoroughly flush joint. 8. Post-Op Care a.No running, jumping or climbing for 2 weeks. b.Do not treat seromas with anything but activity restriction. 9.Results a.Recovery period is 4-8 weeks but dogs may be sound much sooner. b.75 % (30 of 40 cases) are completely sound, 22.5 % minimal lameness, 2.5 % consistent lameness over a 3 year follow-up period. c.Dogs lame after 12 weeks should be scoped for missed joint mice and reevaluated for another cause of lameness. C.Humeral Condyle OCD (Also see elbow incongruity/elbow dysplasia) 1.Second most common site of OCD. Bernese Mountain dogs, Rottweilers, Labrador retrievers and golden retrievers most commonly affected breeds. 2.Lameness usually noted at 5-7 months old. 3.Males more commonly affected than females (2:1 ratio) 4.Bilateral disease is seen in 20-50% of cases. 5.Clinical signs a.Mild or intermittent lameness worse when getting up from rest and with heavy exercise. b.Pain or increased lameness may be noted following sustained extension or flexion and lateral rotation of the elbow. c.Joint effusion may be present. 6.Diagnosis a.Usually confirmed with plain mediolateral and craniocaudal radiographs. b.A radiolucent concavity is noted on the medial and distal trochlear ridge of the humeral condyle. (best seen on craniocaudal radiograph) c.Arthroscopy, CT or arthrotomy may be necessary to confirm the diagnosis or distinguish OCD from a lesion of the condyle secondary to fragmented coronoid process. 7.Treatment a.Removal of the OCD cartilage flap with forage of the subchondral bone is considered the best treatment. b.Arthroscopy or an open surgical procedure on the medial aspect of the elbow provide adequate access to the lesion. c.NSAIDS, analgesics and osteoarthritis modifying agents may be needed in the postoperative period for a short time or indefinitely. 8.Prognosis a.Extremely variable and unpredictable. b.Try to operate cases as early as possible. c.Other procedures may be required if elbow incongruity/dysplasia is present. D.Stifle OCD 1.Fortunately this is infrequent. 2.Usually seen between 4-9 months of age. 3.Most commonly seen in Great Danes, Newfoundland’s, German Shepard’s, Labs, and golden retrievers. 4.Males are slightly more commonly affected than females. 5.Bilateral in 72% of cases. 6.Clinical Signs a.Variable pelvic limb lameness with muscle atrophy and possibly joint effusion. b.Possible clicking sound noted from movement of the flap. c.Lateral condyle more frequently affected (96%) than medial one (4%). 7.Diagnosis a.Flattening of subchondral bone of femur condyle noted on plain radiographs of stifle. b.Don’t confuse with avulsion of the long digital extensor tendon noted in Danes. 8.Treatment a.Medical management for small lesions. b.Arthroscopy or arthrotomy for large lesions and ones with a flap. c.Osteochondral graft from the patient’s stifle is currently the preferred method of treatment. 9.Prognosis a.Fair to guarded due to DJD/OA progression. Jury is still out on osteochondral grafts but results are promising. b.Long-term medications may be necessary to help control lameness. E.Tarsal joint OCD. 1.Third most common site of OCD. Usually noted between 6-12 months of age. Rottweilers and Labrador retrievers account for 70 % of hock OCD cases. 2.Male and females are equally affected. 3.Lesions are bilateral 40 % of the time. 4.79 % of tarsal OCD affect the medial trochlear ridge and 21 % the lateral ridge. 5.Lesions may affect one or both trochlear ridges at multiple sites. Most common location is the plantar aspect of the medial trochlear ridge (80 % of cases). 70 % of cases affecting the lateral trochlear ridge involve the dorsal aspect. Rottweilers in one study accounted for 80 % of cases of lateral ridge OCD and 63 % of those cases had bilateral lesions. 6.Clinical Signs a.50 % have a non-weight bearing lameness. b.Lameness for those cases bearing weight usually worsens with exercise. c.Affected joints usually appear hyperextended. d.Joint swelling is frequently noted on palpation. 7.Diagnosis a.OCD of the medial trochlear ridge is diagnosed on extended plain craniocaudal and slightly flexed mediolateral radiographs. Findings suggestive of medial OCD include increased joint space at the OCD defect, joint effusion and presence of an osteochondral fragment. b.A “sky-line” view of the tarsus with the joint flexed to 90 % and the x-ray beam directed perpendicular to the long axis of the tibia is usually required to visualize OCD of the lateral trochlear ridge. 8.Treatment a.Dog with lameness and a large flap appear to do better if operated early prior to the onset of DJD. (less than 12 months) b.Dogs with small lesions appear to have a better long-term prognosis and may do as well with medical management as they do with surgery. c.Loss of a big piece of the trochlear ridge due to a large OCD defect or removal of excess bone (curettage) at surgery may cause increased joint instability and a poor prognosis. d.Avoid surgical approaches that involve osteotomies. Consider a minimally invasive approach over the lesion or arthroscopy. 9.Prognosis a.Time to maximal postoperative performance was 30 days or less in one study. b.Most cases have some gait abnormalities postoperatively, but are usually better than they were preoperatively. c.Performance at 30 days postop is probably how the dogs will perform long-term. d.Dogs with OCD of the medial trochlear ridge seem to have more postoperative lameness than dog with lateral trochlear OCD. Lateral OCD has less affect on the weight-bearing surface than medial OCD. e.Medical management may be needed long-term for treatment of DJD/OA. |
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