Working Algorithm for Treatment Decision Making for Developmental Disease of the Medial Compartment of the Elbow in Dogs

Theory and development of a unicompartmental resurfacing system for treatment of medial compartment disease of the canine elbow

Medial compartment disease (MCompD) of the canine elbow can be defined as clinical signs attributable to articular cartilage loss of the medial coronoid process (MCP) of the ulna and medial aspect of the humeral condyle without significant lateral compartment pathology. Whereas outcomes associated with treatment of defined cohorts of dogs with MCompD have not been published, the impressions of many surgeons are that non-surgical management or surgical treatment of the MCP alone does not result in long term highly functional outcomes. Thus, alternative surgical options for treatment of MCompD have been developed including various osteotomies and total elbow replacement (TER) with "successful" outcomes reported in case series. Results and data on safety have been reported for relatively few of these procedures and when reported, major complication rates have been >10% and catastrophic complications have been reported. Accordingly, we sought to develop a surgical technique with the objective of obtaining higher levels of safety and efficacy in the treatment of dogs with MCompD. This report describes the rationale for, and development of, a unicompartmental resurfacing system for treatment of MCompD in the canine elbow.

Pathology of Articular Cartilage and Synovial Membrane From Elbow Joints With and Without Degenerative Joint Disease in Domestic Cats

The elbow joint is one of the feline appendicular joints most commonly and severely affected by degenerative joint disease. The macroscopic and histopathological lesions of the elbow joints of 30 adult cats were evaluated immediately after euthanasia. Macroscopic evidence of degenerative joint disease was found in 22 of 30 cats (39 elbow joints) (73.33% cats; 65% elbow joints), and macroscopic cartilage erosion ranged from mild fibrillation to complete ulceration of the hyaline cartilage with exposure of the subchondral bone. Distribution of the lesions in the cartilage indicated the presence of medial compartment joint disease (most severe lesions located in the medial coronoid process of the ulna and medial humeral epicondyle). Synovitis scores were mild overall and correlated only weakly with macroscopic cartilage damage. Intra-articular osteochondral fragments either free or attached to the synovium were found in 10 joints. Macroscopic or histologic evidence of a fragmented coronoid process was not found even in those cases with intra-articular osteochondral fragments. Lesions observed in these animals are most consistent with synovial osteochondromatosis secondary to degenerative joint disease. The pathogenesis for the medial compartmentalization of these lesions has not been established, but a fragmented medial coronoid process or osteochondritis dissecans does not appear to play a role.

Thoracic limb alignment in healthy labrador retrievers: evaluation of standing versus recumbent frontal plane radiography

OBJECTIVE

To report thoracic limb alignment values in healthy dogs; to determine if limb alignment values are significantly different when obtained from standing versus recumbent radiographic projections.

STUDY DESIGN

Prospective cross-sectional study.

ANIMALS

Labrador Retrievers (n = 45) >15 months of age.

METHODS

Standing and recumbent radiographs were obtained and limb montages were randomized before analysis by a single investigator blinded to dog, limb, and limb position. Twelve limb alignment values were determined using the CORA methodology. Measurements were performed in triplicate and intra-observer variability was evaluated by intra-class correlation coefficient (ICC). Limb alignment values were reported as mean ± SD and 95% confidence intervals. Linear mixed models were used to determine if significant associations existed between limb alignment values and limb, limb position, gender, age, weight, and body condition score.

RESULTS

There were significant differences in standing and recumbent limb alignment values for all values except elbow mechanical axis deviation (eMAD). Limb, gender, age, body weight, and body condition score had no effect. ICC values ranged from 0.522 to 0.758, indicating moderate to substantial agreement for repeated measurements by a single investigator.

CONCLUSIONS

Limb alignment values are significantly different when determined from standing versus recumbent radiographs in healthy Labrador Retrievers.

Anatomical study of fibrous structures of the medial aspect of the canine elbow joint

Forces exerted by fibrous structures on the medial aspect of the canine elbow joint have been reported to be involved in elbow pathology. The purpose of this paper is to assess the relationships of the ligamentous and muscular structures of this region of the canine elbow joint, and how they relate to the medial coronoid process. Six cadavers of adult German shepherd cross-breed dogs were used in this study to make intra-articular and vascular injections of this region. Some joints were dissected and some were frozen to saw sagittal or dorsal cryosections to assess the relationships of the myotendinous structures. The brachialis muscle tendon passed through the division of the bicipital tendon of insertion which formed a fibrous tendon sheath that was reinforced by the oblique ligament. The biceps' brachii's main insertion is the radial tuberosity where it inserts along with the cranial branch of the oblique ligament and the cranial branch of the medial collateral ligament. Rotational and compression forces exerted by the insertion of the biceps brachii-brachialis tendon complex onto the ulna might influence medial coronoid disease. Therefore, sectioning these tendons could be considered as a treatment for medial coronoid disease.

Arthroscopic treatment of fragmented coronoid process with severe elbow incongruity. Long-term follow-up in eight Bernese Mountain Dogs

The purpose of this study was to investigate the long-term treatment results of fragmented coronoid process (FCP) in joints with a radio-ulnar step greater than 3 mm. Treatment of these patients only consisted of fragment removal, without correction of the incongruity. The eight Bernese Mountain Dogs (11 joints) included in this study showed obvious clinical signs of elbow disease and were diagnosed with severe elbow incongruity and concomitant FCP in the time period from 1999-2003. At that time, elbow radiography, computed tomography, and arthroscopy were performed. The mean follow-up period was 5.6 years. The follow-up consisted of a telephone questionnaire combined with a clinical and radiographic re-evaluation at our clinic. The questionnaire revealed that all dogs were either free of lameness or only lame following heavy exercise. One dog sporadically required medication after heavy exercise. The owner satisfaction rate was 100%. The clinical re-evaluation did not reveal any signs of pain or lameness in all cases. Range-of- motion was decreased in nine of the 11 elbows. Radiographs revealed an increase in severity of osteoarthritis in every case.In this case series, arthroscopic fragment removal without treatment of incongruity was demonstrated to be a valuable treatment option and may provide a satisfactory long-term outcome.

Intra-articular morphine, bupivacaine or no treatment for postoperative analgesia following unilateral elbow joint arthroscopy

OBJECTIVES

To compare intra-articular morphine or bupivacaine against no treatment following unilateral elbow joint arthroscopy using force plate analysis and pain scoring.

METHODS

Thirty-one dogs were randomly allocated to receive 0·1 mg/kg intra-articular morphine, 0·5 mg/kg bupivacaine or no treatment following elbow arthroscopy. Force plate analysis, pain scoring and kinematic evaluation were performed before anaesthesia, 4 and 24 hours after surgery. Peak vertical force index, symmetry index, rate of loading, rate of unloading, stance time and range of motion were obtained from gait analysis. Pain scoring was performed every 4 hours and interventional analgesia (0·3 mg/kg methadone) was administered if necessary.

RESULTS

Of 29 dogs analysed, peak vertical force index (P<0·001), symmetry index (P=0·01) and rate of unloading (P=0·01) decreased significantly over time in each group; however, this was not affected by treatment. No significant differences were observed in stance time or rate of loading over time. Kinematic (range of motion) evaluation was not complete for all dogs. Pain scores increased significantly at both time points postoperatively in the no treatment group (P=0·007) and in morphine-treated dogs at 4 hours compared to baseline (P=0·03). For intra-articular bupivacaine significant increases in pain scores were not detected (P=0·28).

CLINICAL SIGNIFICANCE

No benefit to intra-articular bupivacaine or morphine was detected using peak vertical force index from force plate analysis. Bupivacaine prevented increases in pain scores at both time points as did morphine at the 24-hour evaluation, compared to no treatment.

Primary flexor enthesopathy of the canine elbow: imaging and arthroscopic findings in eight dogs with discrete radiographic changes

OBJECTIVE

To describe the radiographic, ultrasonographic, computed tomography (CT), magnetic resonance imaging (MRI), and arthroscopic findings in eight dogs with elbow lameness caused by primary flexor enthesopathy.

STUDY DESIGN

Clinical study.

ANIMALS

Eight client-owned dogs.

METHODS

In all dogs, lameness was localized to the elbow by clinical examination. Radiographic examination, ultrasound, CT and MRI were performed prior to arthroscopy. In seven dogs, surgical treatment and subsequent histopathology were performed.

RESULTS

Primary enthesopathy of the medial epicondyle was diagnosed in eight dogs (13 joints) by combining the minimal radiographic changes with specific ultrasonographic, CT, MRI and arthroscopic findings at the medial epicondyle. In all joints, any other pathology could be excluded. Histopathology of the affected tissue revealed degeneration and metaplasia in the flexor muscles.

CONCLUSIONS

Primary flexor enthesopathy at the medial epicondyle is an unrecognized condition and is a possible cause of elbow lameness in the dog. Diagnosis is based on specific imaging and arthroscopic findings.

CLINICAL RELEVANCE

The most important cause of elbow lameness in dogs is medial coronoid disease. Often this condition presents with minimal radiographic and arthroscopic changes. In these cases, primary enthesopathy of the medial epicondyle should be considered as a differential diagnosis, in order to make the correct treatment decision.

Radiographic evaluation of osteotomized ulnar segments following arthroscopic treatment for canine medial coronoid disease

OBJECTIVE

To assess movement of ulnar segments radiographically, following proximal and midshaft ulnar osteotomy or ostectomy after arthroscopic treatment for dogs diagnosed with medial coronoid disease.

METHODS

Fragmentation and cartilage wear were treated arthroscopically and the presence of incongruity confirmed. Osteotomies were performed at the mid-point or proximal third of the length of the ulna. The distance of separation between the ulnar segments and the adjacent radius were measured and followed by serial radiographs postoperatively until healing had occurred.

RESULTS

Proximal oblique osteotomies located at one-third the length of the ulna were associated with the most movement of the ulnar segments, most notably of the proximal segment. Osteotomies or ostectomies performed in the middle demonstrated less segmental movement and on average, slightly longer time to heal. Movement of the ulnar segments in both groups occurred immediately, and then peaked at two to four weeks postoperatively, tending to plateau thereafter.

CLINICAL SIGNIFICANCE

Radioulnar incongruity is considered a facet of the aetiopathogenesis of canine medial coronoid disease. This creates abnormal loads and focal wear along the medial coronoid process. Performing an oblique osteotomy at a location measured at the proximal third of the length of the ulna allows increased movement of the proximal segment, which may result in unloading of the medial compartment. Performing an osteotomy or ostectomy distally dampens segmental movement due to constraint of the interosseous ligament. These findings suggest that a proximal oblique osteotomy at this location creates immediate favourable movement with low morbidity.