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.

Evaluation of a modified radiographic union scale for tibial fractures scoring system in staged bilateral tibial plateau leveling osteotomy procedures and comparison of first and second side radiographic bone healing

OBJECTIVE

To evaluate the inter- and intra-rater reliability of the tibial plateau leveling osteotomy (TPLO) modified radiographic union scale for tibial fractures (mRUST), a semiquantitative scoring system, as compared with the subjective evaluation of radiographic union for staged TPLOs.

STUDY DESIGN

Retrospective study.

ANIMALS

Forty-eight dogs, 96 stifles.

METHODS

Medical records were reviewed for dogs with bilateral cranial cruciate ligament injuries diagnosed at presentation that underwent staged bilateral TPLOs within 6 months and had both immediate and recheck postoperative radiographs. Radiographs were anonymized, reviewers were blinded, radiographic union was evaluated subjectively, and TPLO mRUST scores were assigned.

RESULTS

The subjective evaluation's intra-rater reliability was 0.72 (Kappa 95% CI 0.65-0.79) and inter-rater reliability was 0.33 (Kappa 95% CI 0.28-0.39). The TPLO mRUST scoring system intra-rater reliability was 0.73 (95% CI 0.68-0.78) and inter-rater reliability was 0.56 (95% CI 0.41-0.68). There was no difference in the degree of bone healing quantified by the TPLO mRUST scoring system (95% CI - 0.1-1.2, P = .09) or subjective evaluation (P = .48) between the first and second side TPLOs. The TPLO mRUST scores were positively correlated with subjective healing (r = 0.94, 95% CI 0.92-0.96, P < .0001, and for scores ≥10/12, 99%, 244/246) were subjectively assigned as radiographically healed.

CONCLUSION

The TPLO mRUST scoring system improved inter-rater reliability compared to subjective evaluation of radiographic union.

CLINICAL SIGNIFICANCE

The TPLO mRUST scoring system should be considered as a semiquantitative supplemental tool for evaluating radiographic union.

Rotation of the Tibial Plateau Segment to Control Arterial Haemorrhage during Tibial Plateau Levelling Osteotomy: A Cadaveric Experimental Study and Nine Clinical Cases

OBJECTIVE

 The aim of this study was to describe a simple and effective method to control severe haemorrhage from intraoperative trauma to the cranial tibial artery (CTA) during tibial plateau levelling osteotomy (TPLO) and to report long-term outcomes.

STUDY DESIGN

 Cadaveric descriptive study and retrospective case series. A TPLO was performed in eight cadaveric limbs, followed by intentional laceration of the CTA under fluoroscopic guidance. Dissection of the limb was performed and the relationship between the CTA and the surrounding structures was evaluated. A computed tomography angiogram was performed following TPLO in one cadaveric limb. Medical records from cases that had intraoperative arterial bleeding between 2015 and 2019 were reviewed. Cases were included if bleeding was controlled by following the usual steps for TPLO. Radiographic follow-up 6 to 10 weeks postoperatively and long-term follow-up owner's questionnaire were available.

RESULTS

 During TPLO, the CTA is tightly compressed between the caudal aspect of the proximal tibia and the popliteal musculature. Rotation and compression of the proximal tibia followed by closure of the pes anserinus successfully controlled arterial bleeding during TPLO in nine clinical cases without the need for direct ligation.

CONCLUSION

 Continuing the usual steps of a TPLO can successfully control intraoperative bleeding from the CTA with no long-term complications. This technique should be considered in cases of arterial bleeding during TPLO before direct ligation.

Ex Vivo Evaluation of the Cranial Tibial Artery and Its Compression through Fragment Rotation during Tibia Plateau Levelling Osteotomy: An Angiographic Three-Dimensional Reconstruction

OBJECTIVE

 To illustrate the arterial vascularity of the proximal tibia three-dimensionally and to evaluate the impact of fragment rotation on the cranial tibial artery by tibia plateau levelling osteotomy (TPLO).

METHOD

 Radiographic angiography and computed tomography (CT) were performed on 12 pelvic limbs from six large-breed canine cadavers before and after TPLO. Three-dimensional (3D) models of the stifle, including osseous and vascular structures, were obtained, and the integrity of the cranial tibial artery was assessed. Post-TPLO CT images were used to analyze compression of the cranial tibial artery by the rotated fragment.

RESULTS

 The uncompressed cranial tibial artery caliber, measured proximally and distally to the osteotomy, was 9.52 mm² (6.07-18.90 mm²). In all adequately rotated fragments, the mean caliber of the artery on the level of the osteotomy was 1.57 mm² (0.89-2.93 mm²) after TPLO. This represented a significant decrease of approximately 81%. Only slight cross-sectional area decrease (8.8%) was seen in one limb, which was revealed to have insufficient fragment rotation (2.83 mm). Another limb only showed signs of stretching of the artery (31.51%), which was under-rotated and medially displaced. Pre-TPLO 3D reconstructions were mainly consistent with previous anatomic studies except for the distance between tibial cortex and cranial tibial artery, which appeared closer.

CONCLUSION

 Sufficient fragment rotation leads to compression of the cranial tibial artery. Intraoperative hemorrhage can be caused by laceration of the main cranial tibial artery or by multiple small branches reaching craniolaterally.

Effect of stifle flexion on the position of the cranial tibial artery relative to the proximal tibia in dogs

OBJECTIVE

To determine the effect of stifle flexion on the proximity of the cranial tibial artery to the proximal tibia in canine stifles with an intact or transected cranial cruciate ligament (CCL).

STUDY DESIGN

Ex vivo randomized blinded computed tomographic angiographic study.

SAMPLE POPULATION

Fifteen pelvic limbs from eight greyhound cadavers.

METHODS

The femoral artery and vein were cannulated and injected with 10 mL of iohexol. Each limb was placed in lateral recumbency on an acrylic sheet with predrawn femoral and tibial lines representing angles of stifle extension. Computed tomography was performed before (limbs 1-15) and after (limbs 10-15) CCL transection. The shortest distance between the cranial tibial artery and proximal tibia (dCrTA-PT) was measured at a distance of one patellar length from medial intercondylar tubercle.

RESULTS

Median dCrTA-PT in intact specimens at 70°, 90°, 110°, and 135° was 2.04, 2.05, 2.28, and 2.51 mm, respectively (P = .008). Pairwise comparisons identified a difference between 70° and 135° (P = .007). Mean dCrTA-PT in transected specimens at 70°, 90°, 110°, and 135° was 2.60, 2.57, 2.90, and 2.79 mm, respectively (P = .208). Median overall dCrTA-PT was 2.24 mm in intact specimens (limbs 1-15, all four angles of extension combined) and 2.76 mm in transected specimens (limbs 10-15, all angles combined; P = .01).

CONCLUSION

Flexion of the stifle resulted in a negligible decrease in dCrTA-PT in intact specimens but had no effect in CCL transected stifles.

CLINICAL SIGNIFICANCE

The angle of stifle extension does not appear to have any clinically significant effect on the proximity of cranial tibial artery to the proximal tibia.

Percutaneous tibial physeal fracture repair in small animals: technique and 17 cases

OBJECTIVES

To retrospectively describe cases treated via percutaneous tibial physeal fracture repair (PTPFR), using intra-operative fluoroscopy (IFL) or digital radiography (DR). To describe a technique ("spiking"), used to treat tibial tuberosity avulsion fractures.

METHODS

Clinical data of 14 dogs and three cats were included. The "spiking" technique was described.

RESULTS

Intra-operative fluoroscopy (n = 11) and DR (n = 6) were successfully used in 11 tibial tuberosity avulsion fractures, one combined proximal physeal and tibial tuberosity avulsion fracture, and five distal tibial/fibular physeal fractures. Surgery times ranged from eight to 54 minutes. The "spiking" technique was successfully applied in six tibial tuberosity avulsion fracture cases. Return to function was at a mean (± standard deviation) of 1.9 (± 1.6) weeks. Long-term (>12 months; n = 17) follow-up was available at a mean of 40.6 (± 13.4) months. Major complications consisted of skin irritation from a pin (distal tibia / fibula physeal fracture case; 8 weeks post-PTPFR), and a bilateral grade II medial patella luxation (tibial tuberosity avulsion fracture case; 1.5 years post-PTPFR). One case developed a mild tibial tuberosity avulsion fracture re-avulsion. All conditions in these three cases were not of clinical concern at follow-up and final outcome was graded as good in these and excellent in the other 14 cases.

CLINICAL SIGNIFICANCE

Percutaneous tibial physeal fracture repair can be considered as a technique to treat tibial physeal fractures. The "spiking" technique was successfully applied in six dogs. A larger, prospective case series is indicated to provide additional clinical information.

Systematic review of surgical treatments for cranial cruciate ligament disease in dogs

Surgery for cranial cruciate ligament disease is often recommended; however, it is unclear if one procedure is superior. The aim of this systematic review was to answer the a priori question, "Is there a surgical procedure that will allow a consistent return to normal clinical function in dogs with cranial cruciate ligament disease and is that procedure superior to others?" A systematic literature search was performed through September 2013. Peer reviewed publication in the English language and 6 mo of postoperative follow-up were required. In total, 444 manuscripts were identified and reviewed, and 34 met the inclusion criteria. Two studies provided level 1, 6 provided level 2, 6 provided level 3, and 20 provided level 4 evidence relative to the study question. The most common surgical procedures included tibial plateau leveling osteotomy (TPLO, n = 14), lateral extracapsular suture (n = 13), tibial tuberosity advancement (n = 6). The strength of the evaluated evidence most strongly supports the ability of the TPLO in the ability to return dogs to normal function. It also provided strong support that functional recovery in the intermediate postoperative time period was superior following TPLO compared with lateral extracapsular suture. There was insufficient data to adequately evaluate other surgical procedures.

Effect of doxycycline on contralateral canine cranial cruciate ligament rupture. A prospective randomized clinical trial in 69 dogs

OBJECTIVE

To evaluate whether doxycycline administered to dogs with unilateral cranial cruciate ligament rupture (Uni-CCLR) would decrease the risk of contralateral-CCLR (Co-CCLR). To evaluate predictors for Co-CCLR survival. To evaluate if a predisposition of Labrador Retrievers to Co-CCLR exists when compared to other breeds.

METHODS

In this prospective randomized controlled clinical trial, 69 client-owned dogs with Uni-CCLR were randomly assigned to a doxycycline (group-D: 7.5 mg/kg PO BID x 6 weeks) or non-doxycycline (group-ND: negative control). Medical and imaging data, time from Uni- to Co-CCLR and to follow-up were recorded. Statistics included chi-squared test, logistic regression, Kaplan-Meier survival analysis, log rank test, survival curves, and frailty model (p <0.05).

RESULTS

This study included 32 dogs in group-D, and 37 dogs in group-ND. Median follow-up was 54.5 and 61 months, respectively. Contralateral CCLR occurred in 53.1% and 48.6% at medians of 20 and 11 months, respectively. Doxycycline did not significantly decrease the risk of Co-CCLR (p = 0.83). This risk was decreased by 14.2% with each year of age but increased with each increasing kilogram of body weight and each increasing degree of tibial plateau angle by 5.4% and 9.7%, respectively. Labrador Retrievers were not significantly predisposed (p = 0.37).

CLINICAL SIGNIFICANCE

At the dose regimen investigated doxycycline does not decrease the risk for Co-CCLR.

Accuracy of three pre- and intra-operative measurement techniques for osteotomy positioning in the tibial plateau levelling procedure

OBJECTIVES

To prospectively compare the accuracy of three preoperative measurement techniques in tibial plateau levelling osteotomy (TPLO) planning.

METHODS

Fifty-nine dogs were randomly assigned to one of three measurement techniques; A, B or C. Surgeons measured the intended osteotomy location on preoperative radiographs according to the assigned technique. Measurements were used intra-operatively during osteotomy placement. Postoperative measurements were made by a single blinded observer and compared to preoperative measurements.

RESULTS

Fifty-one dogs were included for final statistical analysis. The mean absolute differences between pre- and postoperative measurements was 1.72 mm ± 0.958, 1.79 mm ± 1.010, and 3.56 mm ± 1.839, for techniques A, B and C, respectively. No significant differences were identified for patient age, gender, limb or surgeon. Techniques A and B were not significantly different (p = 0.8799). Techniques A and B were significantly more accurate than C (p = 0.0001 and p = 0.0003, respectively). Weight was significantly different among the groups (p = 0.047) but the statistical results did not change when an adjustment was made for bodyweight (p = 0.4971, p <0.001 and p = 0.0007, respectively).

CLINICAL SIGNIFICANCE

Preoperative measuring for planning a TPLO osteotomy is recommended. Techniques A and B in the current study were clinically practical and significantly more accurate compared to technique C.

Perioperative risk factors for surgical site infection in tibial tuberosity advancement: 224 stifles

OBJECTIVE

To examine perioperative factors affecting surgical site infection (SSI) rate following tibial tuberosity advancement (TTA).

STUDY DESIGN

Retrospective case series.

SAMPLE POPULATION

224 stifles in 186 dogs.

METHODS

Medical records of dogs that underwent TTA in a single institution were reviewed. Information on signalment, anaesthetic and surgical parameters, as well as occurrence of SSI was recorded. Dogs were followed for a minimum of three months postoperatively. The association between perioperative factors and SSI was assessed using Chi-squared tests and binary logistic regression.

RESULTS

The prevalence of SSI was 5.3% (12/224 TTA). Surgical time (p = 0.02) and anaesthesia time (p = 0.03) were significantly associated with SSI. For every minute increase in surgical time and anaesthesia time, the likelihood of developing SSI increased by seven percent and four percent respectively. The use of postoperative antimicrobial therapy was not significantly associated with lower SSI (p = 0.719). Implants were removed in 1.3% of cases (3/224 TTA).

CONCLUSIONS

The findings of this study suggest that increased surgical and anaesthesia times are significant risk factors for SSI in TTA, and that there is no evidence that postoperative prophylactic antimicrobial therapy is associated with SSI rate.