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Objective: To investigate the impact of surgery resident training on surgery duration in tibial plateau leveling osteotomy (TPLO) and evaluate whether surgery duration differs with each year of residency training., Study Design: Retrospective medical record review., Animals: A total of 256 client-owned dogs underwent TPLO., Methods: Records of dogs that underwent TPLO between August 2019 and August 2022 were reviewed. The effects of the surgeon (faculty/resident) and the procedure (arthrotomy/arthroscopy) on TPLO surgery duration were examined with an analysis of variance, and geometric least squares means (GLSM) were compared. A linear mixed effects model (LMM) was fitted to quantify fixed and random effects., Results: Four faculty surgeons performed 74 (29%) TPLOs, while 10 residents performed 182 (71%) TPLOs under the direct supervision of a faculty surgeon. All TPLOs were conducted with arthrotomy (109; 43%) or arthroscopy (147; 57%). Overall, residents (GLSM, 153 min) required 54% more surgery duration than faculty surgeons (GLSM, 99 min). Surgery duration among first-year residents (GLSM, 170 min) was 15% longer than second- (GLSM, 148 min) and third-year (GLSM, 147 min) residents, whereas the duration did not differ statistically between second- and third-year residents. Arthroscopy, meniscal tear treatment, surgery on the right stifle, and increasing patient weight were also associated with longer surgery duration., Conclusion: The duration of TPLO surgery significantly decreased after the first year of residency, but did not decrease afterward., Clinical Significance: The results will aid with resource allocation, curricula planning, and cost management associated with resident training., (© 2024 The Authors. Veterinary Surgery published by Wiley Periodicals LLC on behalf of American College of Veterinary Surgeons.)

Objective: To evaluate the accuracy of six depth gauges used in three tibial plateau leveling osteotomy (TPLO) plate holes., Study Design: Ex vivo experimental study., Animals and Sample Population: Cadaveric canine limbs (n = 10), one 25-mm-thick wood board, and one 33.8-mm-diameter polyvinyl chloride (PVC) pipe., Methods: A TPLO was performed on 10 canine cadaveric pelvic limbs. Three 3.5-mm plate holes were filled with screws. The remaining three plate holes: a compression hole, a combination compression-locking hole, and a stacked combination compression-locking hole were measured by three observers using six commercial depth gauges and using a micrometer as gold standard. The process was repeated on one wood board and one PVC pipe., Results: Bone measurements collected using two depth gauges with base diameter < 5 mm were smaller than measurements collected using the four depth gauges with base diameter > 5.5 mm (p ranging from < .001 to .038). Mean depth gauge measurements were smaller than micrometer measurements by 2.20 mm for the compression hole, 0.82 mm for the combination hole, and 3.57 mm for the stacked combination hole. Measurement differences among depth gauges were also present for wood board and PVC pipe measurements. Bone measurement variability between depth gauges was less for the combination and compression holes than for the stacked combination hole., Conclusion: Depth gauges lacked accuracy. Measurements differed among gauges and measurement variability varied based on plate hole geometry., Clinical Relevance: Depth gauge measurement accuracy varies based on measuring devices and on 3.5-mm plate hole geometry., (© 2021 American College of Veterinary Surgeons.)

Objective: To determine the influence of interlocking screw threads on the biomechanical properties of repaired canine humeral condylar fractures., Study Design: Ex vivo biomechanical study., Sample Population: Thirty-six humeral condyles., Methods: Simulated fractures of the lateral aspect of the humeral condyle were stabilized by a 3.5 mm interlocking thread screw (ITS) or 3.5 mm buttress thread screw placed in lag (BTS-L) or positional fashion (BTS-P) and axially loaded at a walk, trot, 2-mm displacement, and failure cycles. Compact flute drill bits (CFBs) were used for ITS constructs and standard flute drill bits (SFB) for BTS constructs. The effects of bit type on drilling parameters and screw type on screw insertion properties and fragment stability were assessed., Results: CFB produced a 6°C greater temperature increase (p = .042) and required 20 N higher torque (p = .003) than SFB. Insertional torque was greater for ITS than BTS-P (p = .001) and BTS-L (p = .001). Condylar fragment rotation at failure was lower in ITS (lsmean ± SE, 8.3° ± 1.9°) than BTS-L constructs (14.5° ± 2.3°, p = .011). ITS resisted greater loads (1503 ± 105 N) than BTS-P (1189 ± 99 N, p = .038) but not BTS-L (1249 ± 123 N, p = .121) constructs., Conclusion: Biomechanical performance of constructs was improved with ITS rather than BTS fixation., Clinical Significance: ITS can be considered for stabilization of humeral condylar fractures in adult dogs., (© 2021 American College of Veterinary Surgeons.)

Objective: To evaluate the diagnostic value of still images of needle arthroscopy (SNAR), still images of traditional arthroscopy (STAR), and computed tomography (CT) to diagnose medial coronoid process (MCP) pathology., Study Design: Prospective clinical trial., Animals: Dogs (n = 17) presented for evaluation of elbow dysplasia., Methods: For each case, two SNAR and STAR images of the MCP were reviewed independently and in random order by three board-certified surgeons. Computed tomographic images were reviewed by one board-certified radiologist. Reviewers were blinded to surgical and clinical findings. Surgical findings from real-time TAR with palpation were used as the gold standard. Receiver operating characteristic (ROC) curves and concordance statistics tests for the diagnostic accuracy of MCP fissure, MCP fragment, medial compartment condition, and cartilage score were calculated., Results: Images of 27 elbows joints were reviewed. For MCP fissure detection, areas under the ROC curves for CT (0.84), STAR (0.73), and SNAR (0.57) did not differ. For the detection of MCP fragment, STAR had a larger area under the ROC curve (0.93) compared with SNAR (0.74, P = .015) and CT (0.54, P < .001). Still images of TAR and SNAR had comparable concordance for cartilage score (0.80 and 0.77, respectively) and medial compartment pathology (0.80 and 0.73, respectively)., Conclusion: Still images of NAR, STAR, and CT had similar diagnostic value to identify MCP fissures. Still images of TAR was superior to SNAR and CT to identify MCP fragments., Clinical Significance: The diagnostic accuracy of SNAR varied on the basis of the coronoid lesion being evaluated., (© 2021 The American College of Veterinary Surgeons.)

Objective: To assess the accuracy of three-dimensionally (3-D) printed drill guides in constraining the trajectory of drill tracts for implants in canine thoracic vertebrae., Study Design: Experimental ex vivo study., Sample Population: Five canine thoracic vertebral column specimens., Methods: Guides to constrain drill trajectories were designed on the basis of computed tomographic (CT) imaging of six thoracic vertebrae (T8-T13) and were 3-D printed. The guides were used to create drill tracts in these vertebrae by both an experienced and a novice surgeon, and CT imaging was repeated. The entry point and angulation of actual and planned drill tracts were compared for both surgeons. Unintended cortical violations were also assessed by using a modified Zdichavsky classification., Results: Fifty-eight drill tracts were created in 30 vertebrae. Mean entry point deviation was 1.4 mm (range, 0.4-3.4), and mean angular deviation was 5.1° (range, 1.5°-10.8°). There were no differences between surgeons in entry point deviation (P = .07) or angular deviation (P = .22). There were no unintended cortical bone violations, and all drill tracts were classified as modified Zdichavsky grade I., Conclusion: The 3-D printed guides used in the current study yielded drill tracts with small linear and angular errors from intended paths and 100% accuracy for placement within vertebral pedicles and bodies. This technique was conveniently used by both an experienced and a novice surgeon., Clinical Significance: This technique might be immediately applicable to clinical cases requiring thoracic vertebral stabilization and may allow safe and accurate implant placement for surgeons with varying experience levels., (© 2020 The American College of Veterinary Surgeons.)

Objective: To report the clinical characteristics, surgical management, and medium-term outcomes of total hip replacement (THR) performed in dogs with previous contralateral pelvic limb amputation., Animals: Thirteen client-owned dogs., Study Design: Multi-institutional retrospective clinical study., Methods: Data recorded from medical records included signalment, indication for amputation and THR, and surgical complications. Implant positioning and complications were assessed on radiographs. Clinical outcomes were evaluated during follow-up examinations by one of the authors and through a mobility- and lifestyle-based questionnaire completed by owners., Results: All 13 dogs had satisfactory clinical results at follow-up a median of 3 months (range, 2-36) after THR. No postoperative luxation was recorded. Four dogs had minor complications that did not require additional treatment. The only major complication was one failure of osseointegration of a cementless acetabular cup, and it was successfully revised., Conclusion: Total hip replacement resulted in satisfactory clinical results and acceptable morbidity in this population., Clinical Significance: Total hip replacement should be considered in dogs with severe coxofemoral joint disease and contralateral pelvic limb amputation., (© 2020 American College of Veterinary Surgeons.)

Objective: To assess the influence of a 50% distal ulnectomy on mediolateral carpal stability in the dog., Study Design: Canine cadaveric study., Sample Population: Seven canine thoracic limbs METHODS: Thoracic limbs were placed in a jig to mimic weight bearing with a load representing 30% of body weight. Carpal extension angle was standardized at 190° ± 5°. Frontal plane carpal angles were measured with the limb loaded on craniocaudal radiographs before and after ulnectomy. Valgus and varus stress radiographs with the limb loaded were acquired before and after ulnectomy. The limbs were palpated and were subjectively graded for valgus or varus instability by 2 investigators before and after ulnectomy., Results: Mean (±SD) valgus angulation increased after ulnectomy (2.1° ± 1.7°; P = .017; CI 95  = 0.5°-3.7°) when the limb was loaded without valgus or varus stress applied. Mean valgus angulation increased after ulnectomy (2.7° ± 2.8°; P = .032; CI 95  = -0.2°-5.5°) when valgus stress was applied to the loaded limb. Varus angulation was unchanged after ulnectomy (0.6° ± 4.6°; P = .383; CI 95  = -4.2°-5.3°) when varus stress was applied to the loaded limb. Palpation detected increased valgus score after ulnectomy., Conclusion: Distal ulnectomy with excision of the lateral styloid process induces a slight increase in valgus in canine cadaver carpi. The clinical consequences of that valgus on carpal function and health should be assessed in clinical patients., (© 2017 The American College of Veterinary Surgeons.)

Objective: To evaluate lateral fabellotibial suture (LFTS) and TightRope CCL (TR) extra-articular stabilization biomechanics in the cranial cruciate ligament (CrCL)-deficient canine stifle joint during the stance phase of gait., Study Design: Computer simulations., Animals: Healthy 33-kg Golden Retriever., Methods: LFTS and TR were implemented in a previously developed 3-D quasi-static rigid body CrCL-deficient canine pelvic limb computer model simulating the stance phase of gait. Ligament loads, relative tibial translation, and relative tibial rotation were determined and compared across the CrCL-intact, CrCL-deficient, and extra-articular stabilized stifle joints., Results: Compared to the CrCL-intact stifle, peak caudal cruciate and lateral collateral ligament (LCL) loads were increased in the LFTS-managed stifle, peak caudal cruciate and LCL loads were decreased in the TR-managed stifle, and peak medial collateral and patellar ligament (PL) loads were similar for both techniques. Compared to the CrCL-deficient stifle, peak caudal cruciate, lateral collateral, and medial collateral ligament loads decreased, and peak PL load was similar in the LFTS- and TR-managed stifle joints. Peak relative tibial translation decreased, and peak relative tibial rotation changed from internal rotation to external rotation in the LFTS- and TR-managed stifle joints compared to the CrCL-deficient stifle., Conclusion: Our computer model predicted controlled tibial translation, decreased cruciate and collateral ligament loads, and a change in femorotibial rotation from internal to external with LFTS and TR stifle management as compared to the CrCL-deficient stifle. This study demonstrates how computer modeling can be used to evaluate biomechanics of stifle stabilization surgical techniques., (© 2017 The American College of Veterinary Surgeons.)

Objective: To evaluate the effects of tibial tuberosity advancement (TTA) on canine biomechanics in the cranial cruciate ligament (CrCL)-deficient stifle using a 3-dimensional quasi-static rigid body pelvic limb computer model simulating the stance phase of gait., Study Design: Computer simulations., Animals: A 5-year-old neutered male Golden Retriever weighing 33 kg., Methods: A TTA was implemented in a previously developed canine pelvic limb computer model using the tibial plateau slope and common tangent planning techniques. Ligament loads, relative tibial translation, and relative tibial rotation were determined and compared to CrCL-intact and CrCL-deficient stifles., Results: The TTA significantly decreased peak caudal cruciate ligament load, significantly increased peak lateral collateral ligament load, and significantly changed peak medial collateral ligament load occurrence, while there was no significant difference in peak patellar ligament load compared to the CrCL-intact stifle. Compared to the CrCL-deficient stifle, peak caudal cruciate, lateral collateral and medial collateral ligament loads significantly decreased, while peak patellar ligament load was similar, peak relative tibial translation significantly decreased and peak relative tibial rotation was converted to external rotation in the TTA-treated stifle. Each TTA planning technique generated similar caudal cruciate, medial collateral, and patellar ligament loading as well as relative tibial translation, but lateral collateral ligament loading and occurrence of relative tibial rotation differed significantly across the techniques., Conclusions: Model-predicted stifle ligament loads improved following TTA compared to the CrCL-deficient stifle, but TTA did not restore CrCL-intact stifle biomechanics. The TTA effectively reduced tibial translation, but tibial rotation was not stabilized., (© Copyright 2015 by The American College of Veterinary Surgeons.)

Objective: To compare radiographic and computed tomography (CT) measurements of tracheal size as would be made for the purpose of tracheal stent size selection., Study Design: Cross-over., Animals: Dogs (n = 15)., Methods: Canine cadavers without evidence of tracheal or respiratory disease were used for CT and digital radiography of the neck and thorax. Three observers each made 3 independent measurements at each of 5 tracheal locations, and also measured tracheal length, on each radiograph and for each CT scan on each cadaver., Results: CT tracheal measurements were on average 1.03 mm larger (P < .01) compared with radiographic measurements for all 3 observers., Conclusions: Radiographic measurements of the canine trachea consistently underestimate tracheal size, and CT measurements are preferable for selecting tracheal stent size., (© Copyright 2014 by The American College of Veterinary Surgeons.)

Objective: To evaluate the influence of epidemiologic, surgical, and mechanical factors on the durations of bone consolidation and external fixation after distraction osteogenesis in dogs., Study Design: Retrospective cohort study., Sample Population: Dogs (n = 115) that had corrective osteotomy with circular external fixation (CEF; n = 152) METHODS: Medical and radiographic records (1992-2012) of dogs that had corrective osteotomies were reviewed. Putative variables included age, weight, gender, and breed. Surgery date, delay before distraction, rate and duration of distraction, mechanical complications, and frame removal date were recorded. Radiographic data included bone operated, bone length, osteotomy site, bone and limb size at osteotomy site, distraction distance, and CEF frame size and stiffness., Results: Mean ± SD bone consolidation period was 56 ± 33 days. Mean duration of external fixation was 77 ± 35 days. Twelve fixation failures occurred. Radii healed faster than tibiae (P < .001). Failure of fixation (P = .002) and stiff frames (P = .033) increased duration of bone consolidation. For the tibia, durations of bone consolidation and external fixation decreased with larger bone size relative to limb size (P = .004). For the radius, bone consolidation duration decreased as distraction amount increased (P = .03)., Conclusion: Radii healed faster than tibiae. Wearing frames with low or moderate stiffness, the absence of mechanical complications, a larger distraction distance, and a larger bone size accelerated bone consolidation. Optimizing these factors should accelerate bone consolidation and reduce the duration of external fixation., (© Copyright 2014 by The American College of Veterinary Surgeons.)

Objectives: To compare von Frey mechanical quantitative sensory thresholds (mQSTvF ) between pelvic limbs in dogs before unilateral total hip replacement (THR) surgery; to correlate ground reaction forces (GRF) with mQSTvF ; to assess changes in mQSTvF after THR surgery., Study Design: Prospective clinical study., Animals: Dogs (n = 44)., Methods: mQSTvF and GRF measured using a pressure sensitive walkway were evaluated before, and 3, 6, and 12 months after, unilateral THR. Measurements were recorded from the affected (operated) pelvic limb (APL) and the non-operated pelvic limb (NPL). Random effects analysis and forwards stepwise linear regression models were used to evaluate the influence of time since surgery and patient factors on mQSTvF thresholds., Results: There were no significant correlations between mQSTvF data and age, bodyweight or the GRF variables. Preoperative mQSTvF measured at the APL and NPL did not differ (P = .909). mQSTvF thresholds increased significantly after 12 months in NPL (P = .047) and APL (P = .001). In addition to time, APL mQSTvF values were significantly affected by sex (higher in males, P = .010) and body condition score (higher in leaner dogs, P = .035) and NPL mQSTvF values by sex (P = .038)., Conclusion: Successful unilateral THR results in decreased central sensitization after 12 months., (© Copyright 2014 by The American College of Veterinary Surgeons.)

Objectives: To describe clinical, radiographic, and computed tomographic (CT) assessment of biapical deformities of the radius in dogs and evaluate the effectiveness of their management by use of bilevel hinged circular external fixation frames., Study Design: Prospective, non-randomized cohort study., Animals: Dogs (N = 26: 13 with 14 limbs operated, 13 controls)., Methods: CT scans of the forelimbs were performed and CT-based polymer replicas prepared. Rotation within the elbow joint, varus of the proximal portion of the radius, radial torsion, valgus of the distal portion of the radius, procurvatum, and rotation within the carpal joint were measured on radiographs, on polymer replicas, and on CT scans. Bilevel hinged circular external fixation frames were assembled on polymer replicas and identical frames were placed on dogs. Torsion was corrected acutely and angulation was corrected progressively. Functional outcome was assessed subjectively., Results: Buckling was present preoperatively in operated limbs. Mean (± SD) varus of the proximal portion of the radius was 36 ± 8°, valgus of the distal portion of the radius was 32 ± 5°, external radial torsion was 35 ± 6°, procurvatum was 41 ± 10°, and medial translation was 44 ± 11 mm. Treatment duration was 80 ± 24 days. Buckling was not observed after surgery. Lameness scores improved in all dogs (P < .001)., Conclusions: The forelimbs of dogs with severe biapical radial deformities buckle and have increased radial head rotation and radial torsion. Biapical radial deformities can be managed with proximal and distal radial osteotomies and bilevel hinged circular external fixation., (© Copyright 2014 by The American College of Veterinary Surgeons.)

Objective: To compare the mechanical properties of feline ilial fractures stabilized with either a plate (P), or a plate and IM pin (P + P)., Study Design: Mechanical study., Sample Population: Cadaveric cat pelvii (n = 10)., Methods: Feline ilial fractures (n = 20) stabilized with either P or P + P were subjected to 100 nondestructive load cycles, then loaded to failure. Deformation after cycling, yield load and displacement, stiffness and load at 2 mm of displacement were compared between groups., Results: There were no significant differences between groups for any of the parameters. Variability of data was much larger for the P + P group., Conclusions: No biomechanical advantage was demonstrated. The P + P constructs were not significantly stronger than plates alone in this acutely loaded cadaveric model., (© Copyright 2013 by The American College of Veterinary Surgeons.)

Objective: To determine whether there is a difference between the ability of peak vertical force (PVF), vertical impulse (VI), and percentage body weight distribution (%BW(dist) ) in differentiating which leg is most affected by hip joint pain before total hip replacement (THR) surgery, and for measuring changes in limb use after THR surgery., Study Design: Prospective clinical study., Animals: Dogs (n = 47)., Methods: Ground reaction force (GRF) data were collected using a pressure-sensitive walkway the day before THR surgery and at ∼3, 6, and 12 months postoperatively. PVF and VI expressed as a percentage of body weight (%PVF, %VI), and %BW(dist) were recorded. Regression models performed separately for each outcome were used for statistical analysis., Results: When comparing limb use between the affected limb (AP) and the nonaffected limb (NP) preoperatively, differences between limbs were statistically significant when evaluated using PVF (P = .023), VI (P = .010), and %BW(dist) (P = .012). When evaluating the magnitude of absolute and percentage change difference in AP limb use preoperatively versus postoperatively, differences were statistically significant when evaluated using PVF (P < .001 and P = .001, respectively), VI (P = .001 and P < .001) and %BW(dist) (P < .001 and P < .001)., Conclusion: There appeared to be no difference in the sensitivity of VI, PVF, and %BW(dist) for evaluating limb use before and after THR., (© Copyright 2012 by The American College of Veterinary Surgeons.)

Objective: To compare: (1) the force required to initiate subsidence, and (2) the relative subsidence, of femoral stems implanted into intact femora, and then into the same femora in which an induced fissure had been stabilized by cerclage., Study Design: In vitro, mechanical study., Sample Population: Femora (n=9) from 9 dogs., Methods: Femora were prepared for implantation of an uncemented stem. Stems were implanted with continuous and impact loading. After axial loading until a fissure occurred, the stems were extracted, and the fissure stabilized with double-loop cerclage. Stems were reimplanted, and reloaded to failure., Results: Mean±SD load to initiate subsidence in intact femora was 1706±584 N compared with 2379±657 N for cerclaged bones (P=.002). Mean relative subsidence of intact femora was 3.99±2.09 mm compared with 1.79±2.99 mm for cerclaged bones (P=.091)., Conclusions: The load to initiate subsidence is increased in femora that have fissured, then have been stabilized with double-loop cerclage, when compared with intact femora. The relative subsidence is not different between intact and stabilized specimens., (© Copyright 2011 by The American College of Veterinary Surgeons.)

Objective: To determine (1) risk factors for fibular fracture after tibial plateau leveling osteotomy (TPLO) and (2) if a single postoperative radiographic measurement or measurement ratio of the proximal tibial fragment can be used as a predictor for fibular fracture., Study Design: Multivariate retrospective clinical study., Animals: Dogs (n=326) with cranial cruciate ligament rupture that had TPLO (n=355)., Methods: Medical records (January 2004-November 2007) and radiographs of dogs that had TPLO were reviewed. TPLO plate type, distance between tibial plateau and proximal screw, proximodistal tibial plateau fragment length, tibial plateau width, the presence of a fibular drill hole filled with a screw or not, and fibular fractures were recorded., Results: The odds of having a fibular fracture were 10 times greater in dogs with a fibular drill hole than in dogs without a drill hole. The odds of having a fibular fracture were 1.46 times greater for every 4.5 g increase in body weight. Tibial plateau angle (TPA) at the time of reevaluation was larger than the postoperative TPA and TPA increase was larger in dogs with fibular drill holes than without (P<.01) and in dogs with fibular fractures than without (P<.01)., Conclusion: An unfilled fibular drill hole and increased body weight are risk factors for fibular fracture., (© Copyright 2011 by The American College of Veterinary Surgeons.)

Objective: To evaluate the effect of cranial tibial wedge osteotomy (CTWO) angle on cranial tibial subluxation (CTS) and postoperative tibial plateau angle (TPA)., Study Design: Ex vivo biomechanical study., Sample Population: Canine pelvic limbs (n=6)., Methods: TPA determined from a lateral radiographic projection. CTS under 30% body weight load was measured from radiographs in the intact limb and after transection of the cranial cruciate ligament. A CTWO equal to TPA+10 degrees was performed at the distal extent of the tibial crest, and was stabilized with a custom designed hinge plate and external skeletal fixator. TPA and CTS in the loaded limb was determined from radiographs at 4 CTWO angles: TPA-5 degrees, TPA, TPA+5 degrees, and TPA+7.5 degrees. Comparison of CTS between the intact limb and the 4 CTWO angle groups was performed using 1-way repeated-measures ANOVA and a Dunnett multiple comparison test (significance at P<.05)., Results: CTS was significantly greater than that of the intact limb in the TPA-5 degrees and TPA groups. CTS was not significantly different from the intact limb in the TPA+5 degrees or TPA+7.5 degrees groups with corresponding TPAs of 5.9 degrees and 3.8 degrees, respectively., Conclusion: Using this model, CTS was neutralized at a TPA of approximately 4-6 degrees with a CTWO angle between TPA+5 degrees and TPA+7.5 degrees., Clinical Relevance: A CTWO angle between TPA+5 degrees and TPA+7.5 degrees is necessary to neutralize CTS and achieve a postoperative TPA of 4-6 degrees if the CTWO is performed at the distal extent of the tibial crest and the caudal cortices are aligned.

Objective: To evaluate stance phase limb use after cementless (BFX) total hip replacement (THR) in dogs and to relate postoperative radiographic variables to static bodyweight distribution after surgery., Study Design: Prospective clinical study., Animals: Dogs (n=35) that had THR., Methods: THR was performed using the BFX THR technique. Postoperative pain management regimens were similar for all dogs. Standing bodyweight distribution (%BW(distrib)) was measured using a pressure sensitive walkway and radiographs made before surgery and at 3, 6, and 12 months after surgery. Repeated measures models (with backwards-stepping to obtain the final model) were used for statistical analysis., Results: Temporally, %BW(distrib) to the operated limb increased (P<.0001; normal by 3 months) and decreased to the unoperated limb (P=.0001) and also increased to the pelvic limbs and decreased to the thoracic limbs. %BW(distrib) to the unoperated limb was significantly less than the operated limb at 3, 6, and 12 months after surgery. Postoperative canal fill and femur flare were significantly negatively correlated with change in %BW(distrib) (estimate=-0.24, P=.0413)., Conclusion: BFX THR results in normal %BW(distrib) to the operated limb by 3 months after surgery. A greater fill of the proximal femur may be associated with a suboptimal outcome., Clinical Relevance: BFX THR normalizes standing bodyweight distribution dogs with hip osteoarthritis. Objective evaluation of THR outcome and radiographic features may reveal factors that could be improved through changes in prosthesis design or surgical technique.

Objective: To report surgical planning, technique, and outcome of custom total knee replacement (TKR) performed to manage a medial femoral condylar nonunion in a dog., Study Design: Clinical case report., Animal: A 3-year-old, 20 kg Karelian Bear Hound., Methods: Computed tomographic scan of the left pelvic limb was used to build a stereolithography model of the distal portion of the femur. The model was used to create a custom augment to replace the missing medial femoral condyle and a custom stem for intramedullary condylar cemented fixation. The augment and stem were adapted to femoral and tibial components already available. The model was used to rehearse the surgery and then the custom prosthesis was implanted., Results: Weight bearing returned 8 hours after surgery and improved thereafter. Joint alignment was normal and prosthetic joint motion was 60-165 degrees postoperatively. The dog resumed moose hunting 3 months after surgery. Peak vertical force and impulse of the operated limb measured 17 months after surgery were 65% and 47% of the normal, contralateral limb., Conclusion: Based on short-term follow-up, cemented canine TKR was successfully achieved for management of a severely abnormal stifle joint., Clinical Relevance: With further refinement and development of commercially available prostheses, TKR should be possible for canine patients.

Objective: To report femoral nerve dysfunction caused by focal iliopsoas muscle injury and treated by performing tenectomy of the muscle insertion., Study Design: Case report., Animals: A 4-year-old, castrated male, English Mastiff., Results: Iliopsoas muscle injury caused femoral nerve deficits and severe pain. Focal injury was not detected by ultrasonography or computed tomography but was visible on magnetic resonance (MRI) images. Tenectomy of the insertion of the iliopsoas muscle relieved signs of pain., Conclusions: Femoral nerve dysfunction may occur with iliopsoas muscle injury., Clinical Relevance: Iliopsoas muscle injury should be considered in patients with hip pain and MRI is a useful test for diagnosis. Tenectomy may be indicated for relief of chronic iliopsoas muscle pain.

Objectives: To evaluate the effects of bolt torque, wire size, and component reuse on the ability to maintain wire tension in 3 external skeletal fixation systems., Study Design: Biomechanical study., Methods: Yield strength in tension of 1.0-, 1.2-, 1.5-, and 1.6-mm-diameter wires, and yield strength in torque of Hofmann Small Bone Fixation (SBF) cannulated and slotted bolts and IMEX regular and miniature bolts were determined on a testing machine. The minimum bolt tightening torque needed to prevent wire slippage at clinically recommended wire tensions was determined. Components were tested 10 times, and loads at slippage were recorded., Results: The IMEX system required a mean of 8 Nm of bolt tightening torque to maintain 900 N (1.6-mm wires). The SBF system required a mean of 3 Nm bolt torque to maintain 300 N (1.0-mm wires) and 5 Nm to maintain 600 N (1.2-mm wires). The SBF cannulated bolt required 9 Nm of torque to maintain 900 N (1.5-mm wires). The SBF slotted bolts could only maintain 800 N before yield. The IMEX miniature system required a mean bolt torque of 1.1 Nm to maintain 300 N. The cannulated and slotted bolts from both manufacturers failed to maintain 70% of initial wire tension after 7 and 4 uses, respectively., Conclusions: The IMEX systems and the SBF system using 1.0- and 1.2-mm wires could maintain clinically recommended wire tension safely. Only the IMEX system could maintain clinically recommended wire tension safely using 1.5- or 1.6-mm wires., Clinical Relevance: The SBF system using 1.0- and 1.2-mm wires and the IMEX system using all wire sizes can maintain clinically relevant wire tension. The SBF system using 1.5-mm wires could not. Cannulated and slotted bolts should not be used more than 6 and 3 times, respectively. Nuts should not be reused., (Copyright 2002 by The American College of Veterinary Surgeons)

Objectives: To compare the axial mechanical stability of 3 circular external fixators systems with and without hemispheric washers., Study Design: Experimental study., Methods: The axial stiffness and load necessary to produce 0.5 and 1 mm of displacement of 10 circular external fixator constructs from 3 manufacturers were tested on a materials testing machine. The constructs tested included the Small Bone fixator (SBF; Hofmann S.a.S., Monza, Italy), the IMEX ring fixator (IMEX Inc., Longview, TX), and the Multiplanar C-Fix (MCF; PanVet Distribuzione, Seriate, Italy). Five configurations were tested for each construct: (1) conventional nut fixation, (2) hemispheric washer fixation with connecting rods offset by 0, (3) 1, and (4) 2 holes, and (5) with a ring placed at maximum angulation., Results: The loads resisted at 0.5 and 1 mm of displacement did not differ when frame configurations were compared (P =.25733 and.33769, respectively). The linear stiffness of the following configurations were decreasingly stiff: standard constructs, hemispheric washers with connecting rods perpendicular to rings, hemispheric washers with connecting rods offset by 1 hole, hemispheric washers with connecting rods offset by 2 holes, and ring offset in relation to bone model. The SBF constructs tested were 34% and 41% more rigid than the IMEX and MCF constructs tested despite the larger diameter of the connecting rods for the IMEX frames (6 mm) compared with the SBF frames (5 mm). The IMEX constructs tested were 6% more rigid than the MCF constructs tested., Conclusions: Adding hemispheric washers and angling connecting rods in relation to rings did not influence the loads resisted at 0.5 and 1 mm displacement but decreased construct stiffness., Clinical Relevance: The use of hemispheric washers had minor effects on the biomechanical performance of fixator frames tested in this study when used to angle a ring in relation to connecting rods for circular external fixators., (Copyright 2002 by The American College of Veterinary Surgeons)

Objective: To evaluate the treatment of a spontaneously occurring osteosarcoma in a dog by means of tumor resection and bone regeneration of a 12-cm defect using double bone transport., Study Design: Case report., Animals or Sample Population: An 11 year-old client-owned German shepherd., Methods: After tumor resection, a preassambled Ilizarov frame was secured to the proximal tibia and to the tarso-metatarsal region. Two osteotomies were performed in the proximal metaphysis. The two bone segments were transfixed with 1.5-mm-diameter wires, each secured to a ring, and bone transport was performed until the distal segment reached the talar surface. Cisplatin was administered 14, 35, and 59 days after surgery., Results: Bone regenerate was first visible radiographically 4 weeks after surgery. The frame was removed 162 days after surgery. The hock was protected with a plaster cast because the tarsal arthrodesis was not complete. The dog underwent tibiotarsal arthrodesis 201 days after osteosarcoma resection. The dog died of metastatic disease 239 days after the initial surgery., Conclusions: Even though this dog died of systemic metastases, local recurrence did not develop. Cisplatin chemotherapy did not appear to negatively affect bone regeneration., Clinical Relevance: To our knowledge, the double transport technique has not been previously described in the veterinary literature. In this dog, this technique decreased the duration of treatment compared with a conventional single-segment transport technique., (Copyright 2002 by The American College of Veterinary Surgeons)