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.

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.

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.

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.].

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.

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.

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.

Compartment syndrome of the muscles of mastication in a working dog following a traumatic training incident.

OBJECTIVE: To describe acute compartment syndrome (CS) of the muscles of mastication in a working dog associated with a traumatic training event. CASE SUMMARY: A 2.5-year-old male Belgian Malinois was evaluated for acute blindness, severe diffuse swelling of the head, and inability to close the jaw following a traumatic incident during a bite training drill. During the exercise, the maxillary canine teeth were locked on a bite sleeve. Magnetic resonance imaging of the head and ocular system identified diffuse muscle swelling and hyperintensity, most severe in the muscles of mastication. Ocular abnormalities were not identified. Rhabdomyolysis, CS, and indirect optic nerve injury were supported by measurement of increased intramuscular pressure. Bilateral decompressive fasciotomies over the masseter and temporalis muscles resulted in immediate and marked resolution of the swelling and jaw movement. Blindness, however, did not resolve. NEW OR UNIQUE INFORMATION PROVIDED: CS involving the muscles of mastication may occur as a complication of bite training and may result in irreversible and even life-threatening complications. Emergent decompressive fasciotomy is indicated to reverse swelling; however, visual deficits may not resolve.

Short-Term Clinical and Radiographical Outcome after Application of Anchored Intervertebral Spacers in Dogs with Disc-Associated Cervical Spondylomyelopathy.

OBJECTIVES: The purpose of this study was to assess the short-term outcome of a new intervertebral anchored fusion device (C-LOX) for the treatment of disc associated cervical spondylomyelopathy (DA-CSM) in dogs, based on clinical and radiographical follow-up data. MATERIALS AND METHODS: To be included in the study, dogs had to be clinically affected by DA-CSM treated with surgical distraction/stabilization using the anchored intervertebral spacer (C-LOX). Neurological signs, as well as diagnostic imaging performed pre-, immediately postoperatively, and after 6 weeks and 3 months were assessed. If available, clinical follow-up after 3 months was documented. RESULTS: Thirty-seven cases were enrolled in the study. Outcome at 3 months was available in 25 dogs; improvement of neurological status was documented in 25/25 cases.The most common postoperative complication was screw loosening and/or breakage (n = 22), followed by subsidence (n = 15). Four dogs required revision surgery. CLINICAL SIGNIFICANCE: Distraction/stabilization of DA-CSM in dogs with the C-LOX device resulted in short-term clinical improvement in 33/37 treated cases. The high incidence of screw loosening was taken into consideration and modification of the implant with a new locking system and new screw dimensions was required. The C-LOX device seems to be a valuable alternative to more complicated distraction-fusion techniques.

Results of a survey of Veterinary Orthopedic Society members on the preferred method for treating cranial cruciate ligament rupture in dogs weighing more than 15 kilograms (33 pounds).

OBJECTIVE To determine which method (lateral fabellotibial suture [LFS], tibial plateau leveling osteotomy [TPLO], tibial tuberosity advancement [TTA], or tightrope-like braided multifilament suture secured with metallic buttons [TR]) Veterinary Orthopedic Society (VOS) members preferred for treating cranial cruciate ligament rupture (CCLR) in dogs weighing > 15 kg (33 lb), identify factors associated with this preference, and assess concerns related to surgical implant material used. DESIGN Cross-sectional study. SAMPLE 187 VOS members. PROCEDURES All registered VOS members received an online survey from June to July 2016. Responses were compiled and evaluated for associations with method preferences and perceived complications. RESULTS Overall response rate was 38.4% (221/575). Respondents had graduated from veterinary school a mean of 23 years prior to survey completion, and collectively they performed approximately 30,000 CCLR surgeries annually. The most commonly preferred method was TPLO (147 [78.6%]), followed by TTA (26 [13.9%]), the LFS procedure (11 [5.9%]), and the TR procedure (3 [1.6%]). The preference for TPLO was independent of board certification or college of training (American, European, or other College of Veterinary Surgeons). Non-board-certified surgeons, including general practitioners, also favored TPLO. The most common perceptions were that titanium implants (used for TTA) were associated with the lowest incidence of major complications, whereas braided multifilament suture (used for the TR procedure) was associated with the highest incidence of major complications. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that TPLO was preferred for treating CCLR in dogs weighing > 15 kg and that the TR procedure was perceived as having the highest complication rate. With results of this survey in mind, use of the TR procedure should be considered cautiously when treating CCLR.

Combined Tibial Plateau Levelling Osteotomy and Tibial Tuberosity Transposition: An Ex Vivo Mechanical Study.

OBJECTIVES: The purpose of this study is to compare the load at failure and mode of failure between (1) tibial plateau levelling osteotomy (TPLO) and combined TPLO and tibial tuberosity transposition (TPLO-TTT) (Phase I) and (2) TPLO-TTT and tibial tuberosity transposition (TTT) (Phase II). METHODS: Seven pairs of cadaveric tibiae were tested in each of the Phase I (TPLO vs. TPLO-TTT) and Phase II (TPLO-TTT vs. TTT) experiments. One limb of each pair was randomly assigned to one of two groups for each experimental phase. A tensile force was applied to the patellar ligament until construct failure occurred. RESULTS: There was a significant difference in mean load at failure between TPLO (2092.8 N) and TPLO-TTT (1067.8 N), p = 0.004. All TPLO constructs failed by fracture of the tibial crest. The TPLO-TTT constructs failed by cranial displacement of the distal tibial crest. Additionally, the tibial plateau was displaced in the majority of limbs. There was a significant difference in mean load at failure between TPLO-TTT (1157.6 N) and TTT (1394.0 N), p = 0.025. The TTT constructs demonstrated a similar mode of failure as TPLO-TTT. CLINICAL SIGNIFICANCE: Although ex vivo mechanical testing does not replicate the postoperative clinical scenario, these results demonstrate reduced construct strength of the combined TPLO-TTT technique compared with TPLO or TTT alone. When performing TPLO-TTT, meticulous technique and implants of adequate strength must be employed to create a robust construct and minimize postoperative tibial crest fixation failure.

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.

Distal femoral lateral closing wedge osteotomy as a component of comprehensive treatment of medial patellar luxation and distal femoral varus in dogs.

OBJECTIVE: To describe a cohort of dogs with medial patellar luxation managed with a distal femoral lateral closing wedge ostectomy (DFO) as a component of comprehensive treatment, and to report radiographic and long-term clinical outcome of this technique. METHODS: Medical records of dogs that had a lateral closing wedge DFO as part of management of medial patellar luxation at three veterinary teaching hospitals were reviewed. Surgical reports as well as the preoperative, postoperative, and follow-up radiographs were reviewed. The anatomical lateral distal femoral angle (aLDFA) was determined. Long-term clinical outcome was assessed by telephone interview with the owner. RESULTS: A lateral closing wedge DFO was performed on 66 limbs. The mean pre- and postoperative aLDFA was 107.6° ± 5.8° and 94.1° ± 4.2°, respectively. Cranial cruciate ligament disease was identified in 28/66 affected limbs. Tibial angular deformity, torsional deformity, or both was identified in nine of the 66 limbs. Ostectomy healing was confirmed radiographically in 51/66 limbs. The mean time to union was 73 ± 37 days. All patellae were in the normal position and stable. Complications included infection (2/51), fixation failure (1/51), delayed healing (2/51), and persistent lameness (1/51). CLINICAL SIGNIFICANCE: In this cohort of cases, DFO was a highly successful and repeatable component of surgical treatment for dogs with medial patellar luxation associated with femoral varus. This study also provides more evidence of the high rate of concurrent cranial cruciate ligament disease in cases of medial patellar luxation complicated by femoral varus, and supports an association between stifle instability and medial patellar luxation.

Combined tibial plateau levelling osteotomy and tibial tuberosity transposition for treatment of cranial cruciate ligament insufficiency with concomitant medial patellar luxation.

OBJECTIVES: To describe the surgical technique and report short-term outcome for combined tibial plateau levelling osteotomy and tibial tuberosity transposition (TPLO-TTT) as an option in the treatment of cranial cruciate ligament insufficiency with concomitant medial patellar luxation. METHODS: Medical records were reviewed (2011-2013) of dogs that underwent a standard tibial plateau levelling osteotomy followed by a tibial tuberosity transposition in the frontal plane and stabilized with pin and tension-band wire fixation as a component of surgical treatment for combined cranial cruciate ligament insufficiency and medial patellar luxation. Signalment, fixation method together with any ancillary procedures, function at the in-hospital follow-up examinations, and any complications were recorded. Healing was assessed retrospectively based on the grading criteria of the International Society Of Limb Salvage. RESULTS: Fifteen stifle joints in 11 dogs were identified; 13 stifles were available for in-hospital follow-up. All 13 achieved union (3 with grade III/IV and 10 with grade IV/IV radiographic healing scores); mean time to healing was 10.6 (± 2.9) weeks. Patellar ligament thickening was also identified radiographically in seven of the 13 of stifle joints. All dogs were reported to have mild or no lameness at their last follow-up examination. No catastrophic or major postoperative complications occurred that required additional surgery. Patellar re-luxation did not occur in any of the 13 stifles available for in-hospital follow-up. CLINICAL SIGNIFICANCE: The TPLO-TTT was found to be a reliable and effective technique when used as a part of the treatment of combined cranial cruciate ligament insufficiency with concomitant medial patellar luxation in this series of dogs.

One-stage revision of an infected cementless total hip replacement.

A two-year-old, 44 kg dog with a right Helica cementless total hip replacement (THR) was radiographically diagnosed with implant loosening eight months after the index total hip replacement procedure. Subsequent synoviocentesis and synovial fluid culture revealed a methicillin-resistant coagulase-negative Staphylococcus spp infection of the right THR. A one-stage revision using a hybrid BFX cementless acetabular cup and CFX cemented femoral stem was performed. Vancomycin and micro-silver antimicrobial powder impregnated cement were used in the revision. At re-evaluation 27 months following the revision procedure, the patient did not exhibit any signs of lameness. Radiographic images confirmed stable implants, with bone ingrowth into the cup and no signs of implant loosening. Our report demonstrates the success of a one-stage THR revision when faced with a multi-drug resistant periprosthetic infection, when combined with the use of micro-silver antimicrobial powder and culture-based antibiotic impregnated cement therapy.

Novel TPLO Alignment Jig/Saw Guide Reproduces Freehand and Ideal Osteotomy Positions.

OBJECTIVES: To evaluate the ability of an alignment jig/saw guide to reproduce appropriate osteotomy positions in the tibial plateau leveling osteotomy (TPLO) in the dog. METHODS: Lateral radiographs of 65 clinical TPLO procedures using an alignment jig and freehand osteotomy performed by experienced TPLO surgeons using a 24 mm radial saw blade between Dec 2005-Dec 2007 and Nov 2013-Nov 2015 were reviewed. The freehand osteotomy position was compared to potential osteotomy positions using the alignment jig/saw guide. The proximal and distal jig pin holes on postoperative radiographs were used to align the jig to the bone; saw guide position was selected to most closely match the osteotomy performed. The guide-to-osteotomy fit was categorized by the distance between the actual osteotomy and proposed saw guide osteotomy at its greatest offset (≤1 mm = excellent; ≤2 mm = good; ≤3 mm = satisfactory; >3 mm = poor). RESULTS: Sixty-four of 65 TPLO osteotomies could be matched satisfactorily by the saw guide. Proximal jig pin placement 3-4 mm from the joint surface and pin location in a craniocaudal plane on the proximal tibia were significantly associated with the guide-to-osteotomy fit (P = 0.021 and P = 0.047, respectively). CLINICAL SIGNIFICANCE: The alignment jig/saw guide can be used to reproduce appropriate freehand osteotomy position for TPLO. Furthermore, an ideal osteotomy position centered on the tibial intercondylar tubercles also is possible. Accurate placement of the proximal jig pin is a crucial step for correct positioning of the saw guide in either instance.

Biomechanical evaluation of polymethyl methacrylate with the addition of various doses of cefazolin, vancomycin, gentamicin, and silver microparticles.

OBJECTIVES: Numerous studies have examined the biomechanics of polymethyl methacrylate (PMMA) with added antibiotics, but direct comparison between studies is difficult. Our purpose was to evaluate the effects of the addition of antibiotic drugs and silver on compressive and bending strength of PMMA. Our null hypothesis was that there would be no significant difference in the compressive strength or bending strength of PMMA with the addition of silver or varying amounts of antibiotic drugs. METHODS: Polymethyl methacrylate was mixed with cefazolin, gentamicin, vancomycin, or silver; the control was PMMA alone. Antibiotic groups contained 20 g PMMA and 0.5 g, 1 g, 2 g, or 3 g of antibiotic. Silver groups had 0.25 g silver powder alone added to 20 g PMMA or silver with PMMA and 0, 0.5 g or 1 g of antibiotic. Samples underwent four-point bending and compression testing in air at room temperature and prevailing humidity. Pairwise comparisons between groups and to the ASTM and ISO standards were performed. RESULTS: Compression: All antibiotic and silver groups were weaker than the control. Samples with cefazolin tended to be stronger than other antibiotic groups with equivalent doses of antibiotic. All groups were above the ASTM standard, except 3 g vancomycin. Four-point bending: The addition of antibiotics did not significantly affect bending strength in groups with lower doses of antibiotics. The silver + PMMA group was weaker than the control. No groups were significantly below the ISO standard except the 3 g vancomycin group. CLINICAL SIGNIFICANCE: The addition of antibiotic or silver decreased the biomechanical strength in all samples, but not below the ASTM or ISO standard for most groups. The addition of cefazolin appears to affect strength the least, while high doses of vancomycin alter strength the most.