Comparison of canine femoral torsion measurements using the axial and biplanar methods on three-dimensional volumetric reconstructions of computed tomography images.

OBJECTIVE: To compare the results of the measurement of femoral torsion using the axial measurement method on three-dimensional (3D) volumetric reconstructions of computed tomography images AMM(CT), the biplanar measurement method on 3D volumetric reconstructions of computed tomography images BMM(CT) and a reference standard using the axial measurement method on stereolithographic bone models AMM (SBM). STUDY DESIGN: Ex vivo study. SAMPLE POPULATIONS: Three-dimensional volumetric reconstructions of computed tomography images and stereolithographic bone models from 23 femurs of 14 dogs with hind limb lameness presented for orthopedic evaluation. METHODS: Three-dimensional volumetric reconstructions of computed tomography images and stereolithographic bone models of each femur were created from computed tomography data. Femoral torsion was measured using the AMM (CT) and the BMM (CT) and compared with a reference standard, the AMM (SBM). RESULTS: No differences were noted among the measurement methods (P = .0863). Median measurement of femoral torsion using the AMM (CT) was 34.2°, the BMM (CT) was 36.7°, and the AMM (SBM) was 32.3°. CONCLUSION: No differences existed among the AMM (CT), the BMM (CT), and the AMM (SBM). CLINICAL SIGNIFICANCE: Both AMM (CT) and BMM (CT) can be used to measure femoral torsion in dogs with orthopedic disease.

Ex vivo mechanical properties of a 2.5-mm bone anchor for treatment of cranial cruciate ligament rupture in toy breed dogs.

OBJECTIVE: To determine the mechanical pull-out properties of a 2.5-mm bone anchor implanted in ex vivo femurs of toy breed dogs and to determine whether there is a difference between knotted and knotless configurations. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Eight paired harvested femurs. METHODS: Femurs were assigned to knotted or knotless configuration. Equal numbers of right and left femurs were tested. The caudolateral femoral condyle at the distal pole of the lateral fabella (F2 site) was drilled. The assigned configuration with braided suture combined with the bone anchor was implanted into the F2 site. Each configuration was positioned into a mechanical testing machine to measure yield load, load at 3-mm displacement, ultimate load, stiffness, and mode of failure at the beginning of the canine standing phase angle (150°). RESULTS: Mean ultimate load was 100.14 and 88.69 N (P = .798), mean yield load was 59.72 and 55.85 N (P = .708), load at 3-mm displacement was 46.72 and 43.33 N (P = .656), and stiffness was calculated to be 43.06 and 47.09 N/mm (P = .548) for knotted and knotless configurations, respectively. Mode of failure occurred primarily by anchor pull-out. CONCLUSION: The bone anchor withstood deformation at the estimated forces applied on the native cranial cruciate ligament (CCL) of toy breed dogs in both configurations. CLINICAL SIGNIFICANCE: This bone anchor may constitute a useful alternative for stabilization of the CCL deficient stifle in toy breed dogs. However, before it can be recommended for widespread use in dogs, closely monitored clinical trials must be conducted to assess outcome and complications associated with this implant.

Recommendations for rehabilitation after surgical treatment of cranial cruciate ligament disease in dogs: A 2017 survey of veterinary practitioners.

OBJECTIVE: To report current recommendations made by veterinarians for rehabilitation after surgical treatment of cranial cruciate ligament (CrCL) disease. STUDY DESIGN: Anonymized electronic survey. SAMPLE POPULATION: Veterinarians performing CrCL stabilization. METHODS: An electronic survey was created to collect information on general attitudes toward postoperative rehabilitation and recommendations regarding therapeutic modalities and bandaging. Quantitative data are reported by descriptive statistical analysis, percentage of responses, or mean (±SD). The recommendations for postoperative bandaging beyond 24 hours and for postoperative rehabilitation after extracapsular stabilization compared with after tibial osteotomy were tested by using Cochran-Mantel-Haenszel tests, with P < .05 considered statistically significant. RESULTS: The data analysis included 376 responses (13% response rate). Most (71%) respondents consistently recommended postoperative rehabilitation. Rehabilitation was more than twofold more likely to be recommended after extracapsular stabilization than after osteotomies (P = .0142). Most respondents did not recommend bandaging beyond 24 hours postoperatively (P = .00012). CONCLUSION: Most respondents recommended either formal or informal postoperative rehabilitation therapy. CLINICAL SIGNIFICANCE: If the survey respondents are representative of veterinarians performing CrCL surgery, the current attitude is supportive of postsurgical rehabilitation. Most respondents would welcome evidence-based guidelines for rehabilitation protocols.

Influence of radiographic techniques on the measurement of femoral anteversion angles and a conformation score of pelvic limbs in Labrador retrievers.

OBJECTIVE: To determine repeatability of and correlation between 2 radiographic measurements of femoral anteversion angles (FAA) and to determine their influence on a score derived from tibial plateau angle (TPA) and FAA to predict the risk of cranial cruciate ligament disease (CCLD). STUDY DESIGN: Prospective clinical study. ANIMALS: Forty-eight Labrador retrievers with or without CCLD. METHODS: FAA and CCLD scores were calculated for each limb from extended pelvic radiographs (t-FAA) or angled (a-FAA) projections of the femur by 3 investigators. One investigator repeated measurements twice. Data were analyzed for repeatability, correlation between t-FAA and a-FAA, and their influence on CCLD scores. RESULTS: FAA correlated most strongly with the distance between the femoral head and the femoral axis on mediolateral radiographs, a measurement with excellent repeatability. t-FAA and a-FAA correlated with each other (r > 0.79, P < .0001), although t-FAA were about 1° greater than a-FAA (P = .01). Intrainvestigator and interinvestigator repeatability of the CCLD score was fair when derived from t-FAA and good to excellent when derived from a-FAA. CCLD scores differed between radiographic techniques but led to different predictions in only 9 (10%) limbs, all with lower TPA and CCLD scores than the rest of the population. CONCLUSION: a-FAA correlated strongly with t-FAA and improved the repeatability of CCLD scores within and between investigators. CLINICAL SIGNIFICANCE: A craniocaudal angled beam projection of the femur is a suitable alternative to a ventrodorsal pelvic radiograph when measuring FAA and may improve the repeatability and positive predictive value of CCLD scores.

Metallosis in a Dog as a Long-Term Complication Following Total Hip Arthroplasty.

Metallosis is the accumulation of metallic debris in soft tissues resulting from wear following total joint replacement. A dog was evaluated for lameness 4 years after total hip arthroplasty using a titanium alloy and cobalt chromium total hip system. Radiographs revealed severe acetabular component wear, implant-bone interface deterioration, and peri-acetabular osteolysis. During surgical revision, black periarticular tissue surrounded the implants. Histologically, there was fibrosis and granulomatous inflammation with abundant, intra- and extracellular, black, granular material and smaller amounts of clear punctate to acicular material. Laser capture microdissection followed by x-ray fluorescence microscopy indicated the material contained large amounts of titanium with smaller amounts of vanadium, cobalt, and chromium, confirming the diagnosis of metallosis. The clear material was birefringent under cross-polarized light, stained positive with Oil-Red-O, and thus was consistent with polyethylene. Metallosis exhibits characteristic gross and histologic lesions and is a differential diagnosis for aseptic loosening of hip implants.

Severe Polyethylene Wear Requiring Revision Total Hip Arthroplasty in Three Dogs.

OBJECTIVE: To describe the occurrence of severe polyethylene wear of the acetabular component in 3 dogs that ultimately led to implant failure, and to report the outcome of revision of total hip arthroplasty (THA) in these cases. STUDY DESIGN: Case report ANIMALS: Dogs (n=3). RESULTS: Three dogs with hip dysplasia underwent routine THA before 2 years of age. All dogs became acutely lame 4-5 years after THA. Radiographs revealed acetabular cup wear in all cases, shell fragmentation in 2 cases, and additional stem failure in 1 case. All dogs underwent successful revision surgery, during which severe polyethylene wear and metallosis was observed. Revision surgery provided an excellent clinical outcome in all dogs from 10 months to 4 years post revision. CONCLUSION: Polyethylene wear and implant failure may be a significant long-term complication of THA not previously recognized, which may be especially true when placed at an early age in a large breed, active dog, or in a dog with significant morbidity associated with other limbs. A successful revision was achieved in all 3 dogs. Additional investigation is warranted to document the risk factors associated with severe polyethylene wear in canine THA.

Management of bilateral patellar luxation in an alpaca.

OBJECTIVE: To report surgical management bilateral lateral patellar luxation in a mature alpaca using a combination of trochlear wedge recession (TWR), tibial tuberosity transposition (TTT), and joint capsule imbrication. STUDY DESIGN: Clinical case report. ANIMALS: 9-year-old castrated male Alpaca. METHODS: Bilateral, grade III/IV, lateral patellar luxation was identified by palpation, lameness examination and confirmed with radiography and ultrasonography. Surgical procedures were staged, with the left stifle treated first. Bilateral TWR, TTT, and joint capsule imbrication were performed. Outcome was assessed by radiography and follow up lameness examinations. RESULTS: An immediate improvement in weight bearing occurred after surgery of the left hind limb. Five months after initial surgery, right hind limb patella luxation was corrected. After surgery on the 2nd limb, the alpaca had progressive improvement in weight bearing during hospitalization. At 12 months, there were no signs of lameness and the alpaca had resumed normal activities. CONCLUSIONS: For bilateral lateral patellar luxation, a combination of TWR, TTT, and joint capsule imbrication resulted in excellent long-term outcome.

Synthesis of surgeon and rehabilitation therapist treatment methods of bicipital tenosynovitis in dogs allows development of an initial consensus therapeutic protocol.

OBJECTIVE: To compare the therapeutic approach of surgical specialists, sports medicine and rehabilitation specialists, and veterinarians with rehabilitation certification when treating bicipital tendon disease or tenosynovitis in dogs and to combine this information with existing research to develop a treatment algorithm that provides a framework for treating bicipital tenosynovitis. SAMPLE: 223 respondents to an internet survey of board-certified veterinary surgeons, board-certified sports medicine and rehabilitation therapists, and veterinarians with rehabilitation certification. METHODS: The survey was promoted via multiple listservs, specialist college newsletters, and private relevant social media sites. Answers were compiled and submitted for statistical analysis. RESULTS: Compared to rehabilitation therapists (RTh), surgeons placed less value on the stabilizing function of the biceps tendon and its role in preventing other shoulder morbidities. Similarly, compared to RTh, surgeons were more inclined to select surgery as the primary therapeutic approach and attributed a less optimistic prognosis to conservative therapy outcomes. There were multiple differences between surgeons and RTh in executing a conservative therapy program, with RTh more likely to recommend therapeutic exercise, extracorporeal shockwave, regenerative medicine, therapeutic ultrasound, exercise restriction, photobiomodulation, and pulsed electromagnetic field therapy. RTh were less likely to prescribe NSAIDS or inject corticosteroids. Despite the above noted differences, there were also multiple areas of agreement. CLINICAL RELEVANCE: Consensus agreement, combined with existing research, was used to create a treatment algorithm suggesting how to best address multiple manifestations of bicipital tendinopathy. Such guidelines can be considered to direct therapeutic strategies for this common condition.

Radiographic outcome and complications of tibial plateau leveling osteotomy stabilized with an anatomically contoured locking bone plate.

OBJECTIVE: To evaluate the short-term clinical performance of an anatomically pre-contoured, locking plate in dogs undergoing tibial plateau leveling osteotomy (TPLO) for cranial cruciate ligament (CrCL) disease. STUDY DESIGN: Prospective, multi-center clinical study. ANIMALS: Dogs (n = 56) undergoing TPLO. METHODS: Signalment and operative data were recorded. Preoperative, postoperative, and follow-up tibial plateau angle (TPA) were measured from radiographic images. Intraoperative and postoperative complications were recorded; the latter were categorized as minor if additional surgery was not necessary, and major if surgery was needed to resolve the complication. Bone healing was scored and change in tibial plateau angle (TPACH ) between postoperative and follow up radiographic images was calculated. RESULTS: Mean (± SD) preoperative TPA was 28.6 ± 3.8°, and mean postoperative TPA was 4.8 ± 1.9°. Four intraoperative complications (7.1%) including 2 cases of intra-articular screw placement, 3 minor postoperative complications (5.4%), and no major or catastrophic postoperative complications occurred. Median bone healing grade was 4/4 (excellent union >75% healing). Mean TPACH was 0.15 ± 1.32°. CONCLUSIONS: Use of this anatomically contoured, locking TPLO plate by experienced surgeons is associated with accurate tibial plateau leveling, reliably excellent bone union at follow-up exam, minimal TPACH , and a lower complication rate than previously reported. Confining contouring to the distal shaft of the plate ensures there is precise apposition to the tibial diaphysis and mitigates the risk of intra-articular screw placement.

Fluoroscopic Categorization of Cementless Acetabular Component Positioning.

OBJECTIVES: The purpose of this study was to evaluate a fluoroscopic method of angle of lateral opening (ALO) categorization based on identification of the visible portion of a pre-existing, circular recess within the metal shell of the BioMedtrix BFX acetabular component, which projects as an ellipse at clinically relevant ALO values. Our hypothesis was that there will be an association between the actual ALO and the categorization of ALO based on identification of the visible portion of the elliptical recess on a lateral fluoroscopic image at clinically relevant values. STUDY DESIGN: A custom plexiglass jig was fitted with a two-axis inclinometer and a 24 mm BFX acetabular component attached to its tabletop. Fluoroscopic reference images were obtained with the cup positioned at an ALO of 35, 45 and 55 degrees with a fixed 10 degrees of retroversion. Thirty study fluoroscopic images (10 images at each ALO) were obtained based on randomization at an ALO of 35, 45 and 55 degrees (±0.5 degrees) with 10 degrees of retroversion. The order of the study images was randomized, and a single, blinded observer categorized the 30 study images as representing an ALO of 35, 45 or 55 degrees by comparison to the reference images. RESULTS: Analysis showed perfect (30/30) agreement with a weighted kappa coefficient of 1 (95% confidence interval: -0.717 to 1). CLINICAL RELEVANCE: The results demonstrate that accurate categorization of ALO can be achieved using this fluoroscopic method. This method may prove to be a simple but effective method of estimating intraoperative ALO.

Mechanical analysis of twelve toggle suture constructs for stabilization of coxofemoral luxations.

OBJECTIVE: To compare the mechanical performance of 12 commonly used toggle suture constructs (TSCs). STUDY DESIGN: In vitro biomechanical study. SAMPLE POPULATION: Toggle suture constructs (n = 136). METHODS: TSC evaluated included #5 OrthoFiber, double strand of 5 Ethibond sutures (polyethylene terephthalate suture), 80 lb monofilament nylon, or #5 FiberWire, combined with Piermattei toggle (3/32" Steinmann pin), modified Piermattei toggle (0.045" Kirschner wire), and 1/8" Securos toggle rod for a total of 12 test groups. Acute and cyclic testing were performed using a servohydraulic testing machine and load at failure and cycles to failure were determined. RESULTS: In acute testing, modified Piermattei TSCs failed by toggle deformation and Piermattei and Securos TSCs failed by suture breakage at the eyelet. Mean failure load of Piermattei-#5 OrthoFiber TSC (1416 ± 74 N) was significantly greater than that of Piermattei-#5 Ethibond (883 ± 38 N); both were significantly greater than all other TSCs. Only the Piermattei TSC with #5 OrthoFiber, #5 Ethibond, and 80 lb monofilament nylon did not fail during cyclic testing. CONCLUSION: A combination of the Piermattei toggle and #5 OrthoFiber or #5 Ethibond achieved a higher load at failure than all other groups, and resisted the greatest number of cycles to failure. Long-term mechanical testing of these TSCs are warranted to further define their durability.

Analysis of suture anchor eyelet position on suture failure load.

OBJECTIVE: To compare mechanical performance of 2 orientations of the 5 mm Corkscrew® suture anchor with #5 Fiberwire® . STUDY DESIGN: In vitro biomechanical study. SAMPLE POPULATION: Suture anchor-suture constructs (n=40). METHODS: Acute and cyclic tensile loads were applied to suture threaded through eyelets of 40 anchors perpendicular to the long axis of the anchor. Eyelets were positioned so that the suture pull was in line with (anchor rotation angle of 0° [ARA 0]) or 90° (ARA 90) to the eyelet plane. Load at failure, stiffness, and cycles to failure were determined. RESULTS: All constructs failed by suture breakage at the eyelet. Mean load at failure was significantly higher in the ARA 90 group (634 ± 93 N) compared with the ARA 0 group (495 ± 52 N; P=.0015). No significant difference was found between groups for mean number of cycles to failure (270 ± 177 versus 178 ± 109; P=.2166) and stiffness (50 ± 4 versus 48 ± 5 N/mm; P=.3141). CONCLUSIONS: The Corkscrew® 5 mm suture anchor with Fiberwire® suture fails via suture breakage at the eyelet under higher acute loads if the suture is loaded at an angle of 90° compared with 0° with respect to the plane of the eyelet.

Combination tibial plateau leveling osteotomy and transverse corrective osteotomy of the proximal tibia for the treatment of complex tibial deformities in 12 dogs.

OBJECTIVE: To describe a surgical technique, and outcome, for treatment of proximal tibial deformity (varus, valgus, excessive tibial plateau angle [eTPA], tibial torsion and patellar luxation) by combined tibial plateau leveling osteotomy (TPLO) and transverse corrective osteotomy. STUDY DESIGN: Cases series. ANIMALS: Dogs (n=12; 19 stifle joints). METHODS: Medical records of dogs that had combination TPLO and transverse corrective osteotomy, were reviewed. Pre- and postoperative tibial angulation, tibial torsion, tibial plateau angle (TPA), corrective osteotomy technique, method of fixation, and complications were recorded. In hospital re-evaluation of limb function and alignment and length of time to radiographic healing were reviewed. Long-term outcome was assessed by visual analog scale (VAS) questionnaire and owner telephone interview. RESULTS: Proximal tibial varus or valgus was present in 68.4%; 73.7% had eTPA; and 47.4% had both. Medial patellar luxation (MPL) was present in 57.9%, of which 47.4% had tibial tuberosity displacement. Severe tibial torsion was present in 68.4%. Mean pre- and postoperative TPA was 37.5° and 5.7°, respectively. The mean postoperative mechanical medial proximal tibial angle (mMPTA) and mechanical medial distal tibial angle (mMDTA) were 92.2° (range, 88-96°) and 96.1° (range, 94-101°), respectively. Postoperative surgical complications were documented in 21.0%, which included implant loosening or breakage (5.3%), seroma (5.3%), septic arthritis (5.3%), and infection of the proximal tibia (5.3%). All complications were considered major because they required additional surgery. Mean time to document radiographic healing was 10.4 weeks. In-hospital re-evaluation of lameness was obtained at the same time; 82.4% were not lame or had a mild lameness, 17.6% had severe lameness (2/3 with infection). The VAS evaluation revealed excellent results and owner satisfaction in all ten dogs in which long-term follow-up was obtained. CONCLUSIONS: Long-term clinical outcome of combination TPLO and transverse corrective osteotomy was excellent, and had a high owner satisfaction. Healing times were comparable to standard TPLO with a similar complication rate.

Ex vivo biomechanical evaluation of the canine cranial cruciate ligament-deficient stifle with varying angles of stifle joint flexion and axial loads after tibial tuberosity advancement.

OBJECTIVE: To evaluate the effect of tibial tuberosity advancement (TTA) on cranial tibial thrust (CrTT), retropatellar force (RPF), patellar tendon load (PTL), and patellar tendon angle determined by the tibial plateau angle (PTA(TPA) ) method or common tangent (PTA(CT) ) method in the canine cranial cruciate ligament (CrCL)-deficient stifle joint. STUDY DESIGN: Ex vivo cadaver study. SAMPLE POPULATION: Cadaveric canine hind limbs (n=30). METHODS: Stifle joints were subjected to 3 differing loading conditions using a constrained limb press model (Group 1: 30% body weight axial load at stifle and talocrural joint angles of 135 ± 5° and 145 ± 5°, respectively; Group 2: 30% body weight axial load at stifle and talocrural angles of 145 ± 5° and 135 ± 5°, respectively; and Group 3: 50% body weight axial load at stifle and talocrural joint angles of 135 ± 5° and 145 ± 5°, respectively). The CrCL was transected in situ under load; sensors allowed direct measurement of CrTT, RPF, and PTL. Lateral radiographic projections were used to assess PTA(TPA) and PTA(CT) . Descriptive statistics were used to report CrTT (by design this force returned to 0-point values, defined as the neutral point of advancement [NPA]). At the NPA, RPF was compared with baseline using a 2-tailed sign test. PTL within groups were compared using a paired t-test; pair-wise comparisons of PTA(TPA) and PTA(CT) were performed using a paired t-test. Comparisons between loading conditions were made with a 1-way ANOVA and Tukey's post hoc test. Equivalence tests were used to test mean PTA(TPA) and PTA(CT) for equivalence to 90°. Significance was set at a P-value of .05. RESULTS: CrTT returned to baseline values, and RPF and PTL at NPA were reduced below baseline values in all specimens in a near linear fashion with TTA. At the NPA, PTA(TPA) >PTA(CT) in 2 of the 3 loading conditions, but insufficient evidence to suggest they differed in the third. Mean PTA(TPA) and PTA(CT) varied between loading conditions. The threshold for each of the groups evaluated, at which the PTA could be significantly different from 90°, was larger for PTA(TPA) than PTA(CT) in all groups, as greater variation was observed with PTA(TPA) versus PTA(CT) . CONCLUSION: This study further supports the claim that reduction of CrTT occurs after TTA in the CrCL-deficient stifle joint through an alteration of PTA. Additionally, RPF and PTL also decrease after TTA. The PTA(CT) may be a more precise method of determining PTA.

Outcomes Associated With Osteochondral Allograft Transplantation in Dogs.

The purpose of this study was to retrospectively characterize outcomes and complications associated with osteochondral allograft transplantation for treating chondral and osteochondral lesions in a group of client-owned dogs with naturally-occurring disease. Records were reviewed for information on signalment, treated joint, underlying pathology (e.g., osteochondritis dissecans; OCD), and type, size, and number of grafts used. Complications were classified as "trivial" if no treatment was provided, "non-surgical" if non-surgical treatment were needed, "minor surgical" if a minor surgical procedure such as pin removal were needed but the graft survived and function was acceptable, or "major" if the graft failed and revision surgery were needed. Outcomes were classified as unacceptable, acceptable, or full function. Thirty-five joints in 33 dogs were treated including nine stifles with lateral femoral condyle (LFC) OCD and 10 stifles with medial femoral condyle (MFC) OCD treated with osteochondral cylinders or "plugs." There were 16 "complex" procedures of the shoulder, elbow, hip, stifle, and tarsus using custom-cut grafts. In total there were eight trivial complications, one non-surgical complication, two minor surgical complications, and five major complications for a total of 16/35 cases with complications. Accordingly, there were five cases with unacceptable outcomes, all of whom had major complications while the other 30 cases had successful outcomes. Of the 30 cases with successful outcomes, 15 had full function and 15 had acceptable function. Based on these subjective outcome assessments, it appears osteochondral allograft transplantation is a viable treatment option in dogs with focal or complex cartilage defects. However, no conclusions can be made regarding the inferiority or superiority of allograft transplantation in comparison to other treatment options based upon these data.

Corrigendum: Outcomes Associated With Osteochondral Allograft Transplantation in Dogs.

[This corrects the article DOI: 10.3389/fvets.2021.759610.].

Effect of cranial tibial closing wedge angle on tibial subluxation: an ex vivo study.

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.

Minimally Invasive Osteosynthesis Techniques of the Femur.

A thorough working knowledge of the anatomic landmarks of the femur facilitates anatomic alignment during minimally invasive osteosynthesis (MIO). A variety of fixation techniques, including plate, plate-rod, and interlocking nail, are well suited for stabilization of femoral shaft fractures with MIO techniques. Axis and torsional alignment can be assessed with various intraoperative techniques to ensure that anatomic alignment is obtained.

Measurement of Acetabular Component Position in Total Hip Arthroplasty in Dogs: Comparison of a Radio-Opaque Cup Position Assessment Device Using Fluoroscopy with CT Assessment and Direct Measurement.

OBJECTIVES: The aim of this study was to compare measurements of angle of lateral opening (ALO) and version determined using a radioopaque cup position assessment device imaged with fluoroscopy to measurements obtained by CT and direct measurement in a cadaveric model. Our null hypothesis was that there would not be any difference in the angles measured by the techniques. METHODS: Six cadavers were implanted with BFX acetabular components. The CPAD was placed and images were obtained with fluoroscopy. Measurements were obtained from the radiopaque marker bars on the CPAD device, and version and ALO were calculated. The ALO and version were determined by CT and DM. Comparisons were made using a two-way analysis of variance and a generalized linear model procedure analysis. RESULTS: There were no significant differences between the measurements for ALO (p = 0.275) or version (p = 0.226). Correlation between methods was 0.948 and 0.951 for ALO and version, respectively. The mean difference (standard deviation [SD], and 95% confidence interval [CI]) for ALO were: CT versus CPAD 1.85 degrees (± 2.32 degrees [-2.99-3.31]), CT versus DM 1.96 degrees (± 1.99 degrees [-2.2-4.27]), CPAD versus DM1.74 degrees (±2.21 degrees [-1.13 and 5.24]). The mean difference (SD [CI]) for version was CT versus CPAD 2.86 degrees (±1.56 degrees [ -2.63-1.69]), CT versus DM 1.10 degrees (±1.42 degrees [-1.57-2.09]), CPAD versus DM 1.07 degrees (±0.76 degrees [0.13-2.09]). CLINICAL RELEVANCE: The results demonstrate that intraoperative imaging in cadaveric specimens with the CPAD is an accurate method to determine ALO and version of the acetabular component.

Biomechanical comparison of two alternative tibial plateau leveling osteotomy plates with the original standard in an axially loaded gap model: an in vitro study.

OBJECTIVE: To compare the axial compression stiffness of osteotomized canine tibiae stabilized with Slocum, Securos, or Synthes plates after a tibial plateau leveling osteotomy (TPLO) procedure. STUDY DESIGN: In vitro, paired comparison of cadaveric tibial constructs subjected to mechanical testing under an axial load. SAMPLE POPULATION: Canine tibiae (n=16 pairs) from skeletally mature male and female dogs of various breeds (18-55 kg). METHODS: Tibial pairs (n=16) were randomly assigned to 1 of 2 study cohorts (n=8 pairs/cohort): cohort 1, tibial osteotomy stabilization with a Slocum or a Securos plate, or cohort 2, tibial osteotomy stabilization with a Slocum or a Synthes plate. One tibia from each pair was stabilized with 1 of each plate design assigned to the cohort after TPLO. A 3.2 mm osteotomy gap was maintained during plate application in all constructs. Load and axial displacement were recorded while constructs were loaded to 2000 N in axial compression. Failure loads were not reported because no distinct yield point or failure point was evident within the load range for many specimens. Failure modes were recorded for each construct, and photographs of typical failures were obtained. Stiffness (N/mm) was calculated from load-displacement curves. Paired comparisons of mean stiffness were performed within study groups using a paired t-test. Significance was set at P<.05. RESULTS: The mean construct stiffnesses for the Slocum (383+/-183 N/mm) and Securos (258+/-64.1 N/mm) constructs were not significantly different (P=.164; power=0.566). The mean construct stiffness for the Synthes constructs (486+/-91.0 N/mm) was significantly greater than that of the Slocum constructs (400+/-117 N/mm); P=.0468. Modes of failure for the Slocum (16/16) and Securos (8/8) constructs included plastic deformation of the implant with valgus deformity combined with fibular luxation (2/16 Slocum; 1/8 Securos) or fibular fracture (2/16 Slocum; 4/8 Securos). Most Synthes constructs underwent elastic deformation (7/8). One Synthes construct fractured in the sagittal plane through the tibial plateau depression at the point of load application. CONCLUSIONS: The Slocum and Securos plate/tibia construct have similar stiffness, whereas the Synthes/tibia constructs are significantly stiffer than the Slocum/tibia constructs. Modes of fixation failure observed in this model were consistent with TPLO fixation failures observed clinically. CLINICAL RELEVANCE: Construct stiffness in axial load varies with implant type. Implants that confer higher stiffness to the construct may result in greater fixation stability in tibial metaphyseal osteotomies.