Comparison of radiographic scoring systems for assessment of bone healing after tibial plateau leveling osteotomy in dogs

Introduction

Accurate radiographic assessment of bone healing is vital in determining both clinical treatment and for assessing interventions aimed at the promotion of bone healing. Several scoring systems have been used to evaluate osteotomy changes following tibial plateau leveling osteotomy (TPLO). The goal of this study was to compare the ability of five radiographic scoring systems to identify changes in bone healing following TPLO over time (Aim I), and to evaluate the influence of limb positioning on TPLO osteotomy scoring (Aim II).

Materials and methods

Phase I-A randomized, blinded, prospective study was conducted using similarly positioned postoperative TPLO radiographs from seven dogs taken immediately postoperatively, 6-weeks, and 8-weeks postoperatively. Ten reviewers assessed the radiographs, and five different scoring systems were tested for each set including three previously published ones, a Visual Analog Score (VAS), and a subjective 11-point scale. For each system, responses for 6-week postoperative were compared to 8-week postoperative. Scores were judged as correct (=showing an increase in score), incorrect (=decrease in score), or unchanged (=same score). Phase II-An international group of 39 reviewers was asked to score radiographs from three dogs, taken in different positions, using the VAS grading system. Scores were averaged and comparisons were made for each set.

Results

Phase I-The VAS system identified the greatest number of sets correctly (76%), with the least unchanged scores (15%), and 9% incorrect scores. Phase II-All three patients had an increase in the average difference between VAS-scores for differently positioned radiographs compared to similarly positioned radiographs. The magnitude of change between different positions far exceeded the magnitude of comparison of the similarly positioned radiographs from the 6- and 8-week time point.

Discussion/Conclusion

The VAS system appears to be the most appropriate of the tested systems to identify small changes in bone healing. In addition, the positioning of postoperative TPLO radiographs makes a substantial difference in the healing score that is assigned. Care must be undertaken when performing postoperative radiographs in both the clinical and research setting to ensure accurate assessment of bone healing.

Simple ostectomy to address quadriceps impingement caused by distal femoral malunion in four dogs

Four dogs were evaluated for chronic pelvic limb lameness. Radiographs revealed distal femoral malunion with caudo-proximal displacement, resulting in impingement of the quadriceps from the distal aspect of the proximal femoral segment. All dogs presented with femoral shortening and increased femoral procurvatum when compared with the normal contralateral femur. There was minimal angular or rotational misalignment. Treatment consisted of ostectomy of the fracture segment that was causing quadriceps impingement, with debridement of proliferative fracture callus proximal to the trochlear groove in all dogs. No attempt was made to address sagittal plane deformities. Long-term orthopaedic examination with objective gait analysis in three dogs revealed minimal to no lameness in two and mild residual lameness in one dog. Long-term radiographic analysis revealed fracture-site remodelling with an increase in femoral length and a return of near-normal femoral procurvatum in all dogs. Owner-assessed long-term outcome was excellent in all dogs.

Pilot study measuring the effects of bandaging and cold compression therapy following tibial plateau levelling osteotomy

OBJECTIVES

To compare cold compression therapy, modified Robert-Jones bandage or the combination of cold compression therapy plus modified Robert-Jones bandage on operated limbs following tibial plateau levelling osteotomy in dogs.

METHODS

Twenty-one client-owned dogs with cranial cruciate ligament disease were prospectively enrolled. Dogs were randomly assigned to one of three postoperative treatment groups: cold compression therapy, modified Robert-Jones bandage or a combination of both. Patients were evaluated preoperatively and at 12, 24 and 36 hours following tibial plateau levelling osteotomy. Measurements included weight-bearing on the operated limb, stifle flexion and extension angles and circumference of the operated limb at four levels.

RESULTS

There was no significant difference in weight-bearing, range of motion or limb swelling between groups. There was a trend for dogs in the cold compression therapy and cold compression therapy with a bandage groups to have a greater increase in weight-bearing after surgery compared with the bandage-only group.

CLINICAL RELEVANCE

Cold compression therapy is a safe modality following tibial plateau levelling osteotomy surgery. The trend towards improved use of the operated limb in the groups receiving cold compression therapy compared with those treated with only a bandage may be an indication that these patients are more comfortable in the postoperative period. The small sample size limits interpretation of the data but this pilot study provides data to guide future investigation.