Combined center of rotation of angulation-based leveling osteotomy and tibial tuberosity transposition: An ex vivo mechanical study.

OBJECTIVE: To describe the technique of combined center of rotation of angulation (CORA)-based leveling osteotomy (CBLO) with tibial tuberosity transposition (TTT) and to compare the load to failure between CBLO combined with TTT and CBLO or TTT alone. STUDY DESIGN: Ex vivo study. SAMPLE POPULATION: Twelve pairs of cadaveric pelvic limbs. METHODS: Six pairs of cadaveric tibia were tested in each group (CBLO-TTT versus CBLO) and (CBLO-TTT versus TTT) with each limb randomly assigned to a treatment group. Construct stability was determined by applying a tensile force to each patellar tendon until failure occurred. Load at failure and mode of failure were recorded for each specimen. RESULTS: No difference in mean load to failure was identified between CBLO-TTT (897 N) and CBLO alone (943 N) (P = .81). There was also no difference in the mean load to failure between the CBLO-TTT (928 N) and TTT alone (1046 N) (P = .12). CONCLUSION: Performing a TTT in combination with a CBLO does not weaken the construct failure to load when compared with each procedure performed alone. CLINICAL SIGNIFICANCE: A combined CBLO and TTT could be considered a viable option for concurrent management of a cranial cruciate ligament deficient stifle and medial patella luxation.

Risk factors for reluxation after toggle rod stabilization for treatment of coxofemoral luxation in 128 dogs.

OBJECTIVE: Evaluate the risk factors for reluxation and outcomes for dogs with a toggle rod construct. STUDY DESIGN: Retrospective case series. ANIMALS: One hundred twenty-eight client-owned dogs. METHODS: Medical records from 2007 to 2018 were reviewed for signalment, history, surgery, and outcome for dogs with a coxofemoral luxation repaired with a commercial toggle rod and nylon monofilament suture construct. Univariate and multiple logistics regression analysis were performed to assess risk factors associated with postoperative luxation. Primary veterinarians and owners were contacted for follow-up via telephone or electronic communication. RESULTS: The overall complication rate was 24.2%, and the reluxation rate was 14.8%. There was a decreased risk of reluxation when the cause was traumatic in origin (odds ratio [OR] 0.10) or when the lameness was severe at presentation (OR 0.42). Fifteen of 58 (25.9%) owners contacted completed a follow-up survey. CONCLUSION: Dogs with nontraumatic, low impact luxations were at a higher risk for reluxation. CLINICAL SIGNIFICANCE: Dogs of any body condition with a traumatic coxofemoral luxation are at lowest risk for reluxation.

Short-Term Complications following Single-Session versus Staged Bilateral Tibial Plateau Levelling Osteotomies Stabilized with Locking Plates for Treatment of Bilateral Cranial Cruciate Ligament Disease: A Retrospective Study.

OBJECTIVE: The aim of this study was to compare complications between dogs with bilateral cranial cruciate ligament disease treated with single-session bilateral tibial plateau levelling osteotomies (BSSTPLO) versus staged bilateral TPLO (STPLO) procedures stabilized with locking plates. STUDY DESIGN: Medical records of client-owned dogs treated with BSSTPLO or STPLO stabilized with locking plates between March 2017 and July 2018 at two associated institutions were reviewed. Patient data and complications from 37 dogs with BSSTPLO and 18 with STPLO were compared between groups. Major complications were defined as any complication that required further surgical or medical treatment whereas minor complications did not. RESULTS: Incidence for major complications for BSSTPLO and STPLO was 7/37 and 6/18 respectively. Incidence for minor complications for BSSTPLO and STPLO was 3/37 and 2/18 respectively. No significant differences in minor or major complication rates existed between study groups (p = 0.2). Mean body weight was significantly higher in the STPLO group (p = 0.001); however, no correlation between weight or BCS and complication rate existed within either group. Increasing age was the only significant risk factor for major complications (p = 0.01) in either group. CONCLUSION: Our findings support the claim that BSSTPLO and STPLO performed with locking implants have similar complication rates. The decision to perform BSSTPLO or STPLO in dogs with bilateral cranial cruciate ligament disease should be based on other considerations rather than just complication rates.

Impact of postoperative antibiotics on rates of infection and implant removal after tibial tuberosity advancement in 1,768 canine stifles.

OBJECTIVE: To report infection rate, implant removal rate, and postoperative antibiotic therapy after tibial tuberosity advancement (TTA) in dogs. STUDY DESIGN: Retrospective study. ANIMALS: One thousand seven hundred sixty-eight stifles in 1,732 dogs. METHODS: Medical records (January 2007-December 2011) of dogs treated with a TTA were reviewed. Cases were included if at least 1 year of postoperative follow-up was available and no additional procedures were performed on the stifle. Date of surgery, date of culture, culture and susceptibility results, postoperative antimicrobials used, and any implant removals were recorded. Use of postoperative antibiotics and implant removal were evaluated statistically for effect on infection occurrence and resolution. RESULTS: Postoperative infections were diagnosed in 82 of 1,768 (4.6%) stifles. Implants were removed from 32 (39%) stifles, with plate and screw removal only in 23 (71.9%) stifles. The rate of infection did not differ between dogs with or without postoperative antibiotic therapy. However, dogs receiving postoperative antibiotic therapy were at risk for developing an oxacillin-resistant infection (P = .001). Oxacillin-resistant infections were associated with a requirement for implant removal to achieve resolution compared with other types of bacterial infections (P < .05). CONCLUSION: No benefit was detected with the use of postoperative antibiotics after TTA in this population. Implant removal was infrequent, and the requirement for cage removal was not commonly required for infection resolution. CLINICAL SIGNIFICANCE: This study does not provide evidence to support postoperative antibiotic therapy after TTA. Postoperative infection can be treated in most dogs without removal of the TTA cage.

Biomechanical Comparison of Four Methods of Fixation of a Polymeric Cranial Cruciate Ligament in the Canine Femur and Tibia.

OBJECTIVE: The aim of this study was to compare the biomechanical properties of four different methods of artificial cranial cruciate ligament fixation in canine cadaveric tibias and femurs. METHODS: Femurs and tibias from skeletally mature large breed canine cadavers were assigned into four fixation groups: group 1, 4.5-mm interference screw (IS); group 2, 4.5-mm IS and 4.0-mm screw and spiked washer (SW); group 3, 5.0-mm IS; group 4, 5.0-mm IS + SW. RESULTS: The mean ultimate load was significantly greater for femur fixations than for tibias, when a SW was added, and for 5.0-mm IS compared with 4.5-mm sizes. There was also a significant interaction between SW and IS size. A SW significantly increased stiffness, a 5.0-mm IS in femurs provided more stiffness than 4.5-mm IS and was greater than 5.0-mm IS in tibias. In tibias, a 4.5-mm IS was stiffer than a 5.0-mm IS and a 4.5 IS + SW had greater stiffness than a 5.0-mm IS + SW. Groups 1 to 3 and tibias in group 4 failed by artificial ligament pullout. Nine femurs in group 4 failed by fracture, 5 by artificial ligament pullout, and 1 by artificial ligament tearing. CLINICAL SIGNIFICANCE: A 5.0-mm IS + SW provided superior artificial ligament fixation strength in femurs and tibias compared with a 4.5-mm IS without SW. Overall, artificial ligament fixation with 5.0-mm IS in femurs had the mechanical characteristics that most closely matched those reported in normal canine cranial cruciate ligaments.

Results and complications after removal of tibial tuberosity advancement cage for treatment of surgical site infections: A retrospective study.

OBJECTIVE: To describe the surgical technique and report the short-term results after removal of tibial tuberosity advancement (TTA) cages in dogs with surgical site infections (SSI). STUDY DESIGN: Retrospective clinical study. ANIMALS: Seventeen client-owned dogs. METHODS: Medical records of dogs treated for SSI by removal of a TTA cage between November 2012 and May 2015 were reviewed. Information collected included signalment, physical examination findings, affected stifle, cage size, date of SSI onset, time elapsed to implant removal, duration of procedure, culture results, any complications encountered, timing of follow-up recheck, and short-term results. RESULTS: Seventeen dogs (20 stifles) were included. Clinical signs related to SSI started at a mean of 403 days after TTA, and implants were removed 474 days (mean) after TTA. No intraoperative complications were reported. Postoperative complications occurred in 40% of dogs. Three dogs developed major complications, including a tibial tuberosity fracture. Eighty-five percent of owners reported complete resolution of clinical signs related to the SSI and were satisfied with the outcome. CONCLUSION: Surgical site infections were short- and long-term complications successfully treated by removal of the TTA cage in the majority of dogs in this study, although complications were common. CLINICAL SIGNIFICANCE: Removal of the TTA cage can be considered as an adjunct to treat SSI but has the potential for postoperative complications.

Short-Term Prospective Clinical Evaluation of a Polyglycolic Acid Tibial Tuberosity Advancement Cage Implant.

This study investigated the short-term radiographic healing of the osteotomy following tibial tuberosity advancement (TTA), maintenance of patellar tendon angle (PTA), and complications in dogs receiving a polyglycolic acid (PGA) TTA cage. Patients diagnosed with unilateral cranial cruciate ligament disease requiring a 9- or 12-mm TTA cage were included. Twenty-six consecutive client-owned dogs were prospectively selected for this clinical study. Age, weight, sex, breed, cage size, surgery date, and follow-up time were recorded. Radiographs were scored for healing and measured for PTA immediately, at 6 wk, and at 10 wk postoperatively. All stifles were assessed for complications throughout the study period. Stifles with PGA cages had similar overall healing scores compared to previously reported values for metallic cages, and the PTA was well maintained at 6 and 10 wk postoperatively. Polyglycolic acid cages were associated with a higher complication rate (10/26, 38%; 95% confidence interval, 0.19-0.61) compared with previously reported complication rates for metallic cages. Despite favorable healing scores and overall PTA maintenance, PGA cage use resulted in a high complication rate. Proposed advantages offered by this particular implant over currently used metallic cages are offset by this high complication rate. Additional investigation of bioabsorbable materials and implant design should be considered.

Comparison of complications following tibial tuberosity advancement and tibial plateau levelling osteotomy in very large and giant dogs 50 kg or more in body weight.

OBJECTIVES: To analyse and compare major complications in dogs ≥50 kg undergoing tibial tuberosity advancement (TTA) or tibial plateau levelling osteotomy (TPLO) for treatment of cranial cruciate ligament disease. METHODS: Medical records and radiographs of client-owned dogs (≥50 kg) treated for cranial cruciate ligament disease with either TTA or TPLO between January 2011 and November 2015 were reviewed. Ninety-one TTA cases and 54 TPLO cases met the study inclusion criteria. All complications within one year of surgery were recorded. Major complications were those requiring surgical revision or intervening medical therapy to resolve. Logistic regression analysis evaluated for associations with major complication occurrence. Major complications were statistically compared between TTA and TPLO treatment groups. RESULTS: Incidence of major complications following TTA and TPLO surgery were 19.8% and 27.8%, respectively. Surgical site infection (SSI) was the single most common major complication following both TTA (15.4%) and TPLO (25.9%) surgery. There were no significant differences between TTA and TPLO treatment regarding the rate of SSI, surgical revision, or overall occurrence of major complications. Postoperative antibiotic therapy significantly reduced the risk of a major complication in all dogs ≥50 kg (p = 0.015; OR: 0.201: 95%CI: 0.055-0.737). CLINICAL SIGNIFICANCE: Major complications occurred frequently following TTA and TPLO treatment of cranial cruciate ligament disease in dogs ≥50 kg. The increased chance for SSI should be considered and postoperative antibiotic therapy is recommended.

Evaluation of an intra-articular synthetic ligament for treatment of cranial cruciate ligament disease in dogs: a six-month prospective clinical trial.

OBJECTIVE: Evaluate the short-term outcomes of a novel synthetic ligament for treatment of naturally occurring canine cranial cruciate ligament disease. STUDY DESIGN: Prospective clinical study. ANIMALS: Dogs with unilateral cranial cruciate ligament disease (n = 50). METHODS: Patient parameters evaluated included a five-point lameness score, evaluation of craniocaudal stifle instability, and radiographic findings over 24 weeks. Any postoperative complications were recorded. RESULTS: Thirty-four out of 42 dogs experienced significant improvements in lameness between the preoperative and 24 week time points. Lameness scores in those dogs improved significantly at all measured time intervals after postoperative week 2. Recurrence of stifle instability increased significantly over the study period from immediate postoperative measurements. Cranial drawer recurred in seven out of 42 of dogs by week 4 and 18/42 by week 24. Implant changes were not noted between the immediate and six-month postoperative radiographs except where complications occurred. Overall, 25 dogs experienced a total of 32 complications (22 major and 10 minor). Sixteen dogs had major complications, and nine had minor complications. CONCLUSION: The procedure was generally effective at improving lameness scores, but did not consistently maintain postoperative stifle stability and had an unacceptably high complication rate. This synthetic ligament procedure cannot be recommended for use in its current form.

Prospective Randomized Clinical and Radiographic Evaluation of a Novel Bioabsorbable Biocomposite Tibial Tuberosity Advancement Cage Implant.

OBJECTIVE: To evaluate the suitability of a novel bioabsorbable biocomposite cage (BC) implant for use in tibial tuberosity advancement (TTA) surgery in dogs with cranial cruciate ligament (CrCL) disease and to compare radiographic osteotomy healing scores and complications between groups that received either a BC or stainless steel cage (SSC). STUDY DESIGN: Prospective randomized clinical study. ANIMALS: Dogs with unilateral CrCL rupture (n=56). METHODS: TTA was performed in 60 consecutive dogs using either a BC (30 dogs) or SSC (30 dogs). Patient parameters, 6 week and 6 month postoperative radiographic osteotomy healing scores, time elapsed to postoperative rechecks, and complications were compared between groups. Osteotomy healing was graded using a 5-point (0-4) scale. Data were analyzed using Wilcoxon Rank Sum tests and χ(2) tests with significance set at P<.05. RESULTS: Fifty-six dogs (30 BC, 26 SSC) had complete medical and radiographic records at 6 months for inclusion in data analysis. Three complications occurred in the BC group (1 major, 2 minor) and 2 occurred in the SSC group (2 minor). There was no statistical difference in patient parameters, 6 week healing scores, or complications between BC and SSC groups. Healing scores at 6 months were significantly higher in the BC group (3.3 ± 0.52) compared to the SSC group (2.9 ± 0.69; P=.04). CONCLUSION: Based on improved BC osteotomy healing scores 6 months after surgery with no significant differences in complications compared to SSC, BC TTA cages are a viable alternative to SSC.

Fracture repair using a polyaxial locking plate system (PAX).

OBJECTIVES: To report outcomes and complications of dog and cat fractures treated with the polyaxial locking plate system (PAX). STUDY DESIGN: Case series. ANIMALS: Dogs (n = 60) and 2 cats. METHODS: Medical records (December 2009-March 2011) of dogs and cats with fractures treated with the PAX system were reviewed. Cases with adequate follow-up to document a functional union, had surgery performed by an author, had no prior treatment of the fracture(s), and with complete operative records were included. Signalment, body weight, bone(s) fractured, area of bone fractured, fracture classification, concurrent orthopedic injuries, complications, time to functional union, if minimally invasive plate osteosynthesis (MIPO) techniques were used, plate size, number of plates, bone graft use, and ancillary methods of fixation were recorded. Additionally, fracture segment: plate length, screw, number of plate holes, number of empty screw holes overlying/adjacent to the fractures, number of cortices engaged above/below the fracture was evaluated. Variables were evaluated statistically for effect on complications and functional union. RESULTS: Sixty-two animals were included. Mean time to functional union was 7.1 weeks. Complications occurred in 12 animals (19%) and plate failure occurred in 3 (5%). Statistically significant factors that affected time to functional union were the presence of multiple injuries and age. Those associated with complications were double plates and number of cortices engaged above and below fractures. CONCLUSIONS: The PAX system allows for multidirectional screw insertion with an overall complication rate and time to functional union similar to other fracture repair implant systems.

The effect of cancellous autograft and novel plate design on radiographic healing and postoperative complications in tibial tuberosity advancement for cranial cruciate-deficient canine stifles.

OBJECTIVE: To assess the effect of autogenous cancellous bone graft (autograft) and novel plate use on radiographic healing and complications in tibial tuberosity advancement (TTA) for treatment of cranial cruciate ligament (CrCL)-deficient stifles in dogs. STUDY DESIGN: Prospective clinical study. ANIMALS: Consecutive dogs (n=125) with unilateral CrCL-deficient stifles. METHODS: Four treatment groups: CPG, conventional plate with autograft; CPNG, conventional plate without autograft; NPG, novel plate with autograft; NPNG, novel plate without autograft were studied. Radiographs from 60 dogs were scored for healing at 6 and 10 weeks postoperatively; all 125 dogs were assessed for radiographic complications. Variables evaluated for relationship with healing scores and radiographic complications were age, weight, sex, cage and plate size, implant type, and graft use. RESULTS: Dogs with autograft had overall higher healing scores at 6 and 10 weeks. Radiographic complications occurred in 13 dogs (12 minor, 1 major), and were not influenced by graft or novel plate use. CONCLUSION: Autograft increases healing scores, but was not found to have a significant impact on the rate of complications in TTA. The novel plate was not found to have healing scores or radiographic complication rates significantly different from the conventional plate design.

Radiographic and clinical changes of the tibial tuberosity after tibial plateau leveling osteotomy.

OBJECTIVE: To investigate radiographic changes of the tibial tuberosity after tibial plateau leveling osteotomy (TPLO) surgery and identify clinical findings and risk factors associated with such changes. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Hundred and eighty-six client-owned dogs (219 stifles) that had TPLO surgery. METHODS: Patient data retrieved included radiographic changes of the tibial tuberosity during re-examination, age, body weight, whether unilateral or single-session bilateral surgery had been performed, location of the anti-rotational pin, approximate tibial tuberosity area, and approximate average tibial tuberosity width. RESULTS: Fracture with resulting caudal displacement of the proximal tibial tuberosity (1.4%; 3 of 219) occurred less frequently than non-displaced tibial tuberosity fractures (7.3%; 16 of 219). Age, weight, average tibial tuberosity width, location of the anti-rotational pin, and single session bilateral surgery were identified as risks factors for non-displaced fracture. Weight divided by the square of the average tibial tuberosity width may be a stronger risk factor than either weight or average tibial tuberosity width alone. CONCLUSIONS: Dogs undergoing single session bilateral TPLO surgery are at greater risk for developing non-displaced tibial tuberosity fractures. The non-displaced tibial tuberosity fracture does not appear to adversely affect outcome or lead to tibial tuberosity avulsion. Significant risk factors for fracture of the proximal tibial tuberosity with caudal displacement were not identified. CLINICAL RELEVANCE: Factors including age, weight, tibial tuberosity thickness, and conditions that may enhance strain on the tibial tuberosity, such as single-session bilateral procedures, may increase risk of fracture.

Results of single-session bilateral tibial plateau leveling osteotomies as a treatment for bilaterally ruptured cranial cruciate ligaments in dogs: 25 cases (2000-2001).

The records of 25 dogs with bilaterally ruptured cranial cruciate ligaments (CrCL) treated with single-session bilateral tibial plateau leveling osteotomies (TPLOs) were reviewed. The mean age and body weight at presentation were 4.9 years and 36.1 kg, respectively. Minor complications occurred in five dogs. Good or excellent function occurred in 19 of 25 dogs at a mean of 6.9 weeks postoperatively. Owner evaluation revealed that the 88% of dogs had good or excellent function at an average of 14.3 months postoperatively. This study demonstrated that single-session bilateral TPLOs are an effective treatment for bilaterally ruptured CrCLs with minimal morbidity and complications.

Malignant transformation of an aneurysmal bone cyst in a dog.

OBJECTIVE: To report malignant transformation of an aneurysmal bone cyst in a dog. STUDY DESIGN: Case report. SAMPLE POPULATION: Client-owned dog. RESULTS: A 5-year-old male Labrador retriever was diagnosed with an aneurysmal bone cyst of the distal aspect of the right ulna. Surgical curettage resulted in remission of clinical signs for 33 months. Because of recurrence of clinical signs, a distal ulnar ostectomy was performed. Histopathologic examination of the excised specimen revealed a moderately differentiated chondrosarcoma at the level of the bone cyst. Limb function was normal for 17 months until a subcutaneous mass, determined to be a chondrosarcoma, occurred at the level of the shoulder. A right forequarter amputation was performed. CONCLUSIONS: Aneurysmal bone cysts are benign but may be transformed into a malignancy after surgical manipulation. Complete surgical excision should be attempted where possible. In this case, distal ulnar ostectomy was an effective means of preserving limb function and preventing local recurrence of chondrosarcoma.

Evaluation of the analgesic properties of acepromazine maleate, oxymorphone, medetomidine and a combination of acepromazine-oxymorphone.

OBJECTIVE: To determine the presence and duration of analgesia after oxymorphone, acepromazine maleate, acepromazine-oxymorphone combination and medetomidine administration in dogs. STUDY DESIGN: Blinded, controlled study. ANIMALS: Six adult beagle dogs. METHODS: Each dog participated in five trials receiving acepromazine maleate (0.2 mg kg-1 IM), oxymorphone (0.2 mg kg-1 IM), acepromazine-oxymorphone drug combination (0.2 mg kg-1 each IM), medetomidine (20 µg kg-1 IM) and sterile saline (control). Two specially designed instruments were used for analgesia determination: a heat device (HD) utilized a linear ramped intensity incandescent bulb and a pressure device (PD) consisted of a pneumatic cylinder that protruded a 2.5-cm bolt. The minimum pressure and heat necessary to produce an avoidance response were determined. Analgesia testing was performed prior to and at 30-minute intervals for six hours after drug administration. RESULTS: Oxymorphone, acepromazine-oxymorphone and medetomidine significantly elevated both pressure and heat response thresholds compared to controls and acepromazine. Both medetomidine and acepromazine-oxymorphone provided a significantly longer duration of analgesia than oxymorphone. No adverse effects were observed at any of the thermal or pressure application sites. CONCLUSIONS: Oxymorphone, medetomidine and acepromazine-oxymorphone produced significant analgesia with medetomidine and acepromazine-oxymorphone providing the longest duration of analgesia.