Initial psychometric testing and validation of the French version of the Canine Brief Pain Inventory.

OBJECTIVE: The Canine Brief Pain Inventory (CBPI) is an owner-completed questionnaire quantifying the severity and impact of chronic pain in dogs. The English version of the CBPI was adapted into French and the objective of this study was to validate this French version of the CBPI. STUDY DESIGN: Prospective clinical study. ANIMALS: A group of 32 dogs with a medical history, clinical signs and radiographic evidence consistent with osteoarthritis. METHODS: Owners of dogs with osteoarthritis who were native French speakers completed a single administration of the translated questionnaire. The psychometric properties were evaluated including construct validity (by factor analysis), reliability (internal consistency) and convergent validity. RESULTS: Factor analysis on the responses from this cohort confirmed a two-factor questionnaire: the Pain Severity (PS) factor and the Pain Interference (PI) factor. The mean inter-item correlation for PS and PI questions was 0.74 and 0.53, respectively. These findings reveal strong internal consistency, suggesting that the questions contained within each factor measure the same concept and can be pooled to generate the PS score (PSS) and PI score (PIS). Cronbach's α was 0.91 and 0.87 for PSS and PIS, respectively. There was strong negative correlation between PSS and PIS with the overall quality of life score (r = -0.62 and r = -0.79, respectively, with p < 0.001 for both), consistent with the hypothesis that increases in PS and PS with function are highly correlated with a corresponding decrease in overall quality of life. CONCLUSIONS AND CLINICAL RELEVANCE: Initial validation of this French version of the CBPI represents an important step in the expanded use of validated owner-completed outcome assessment instruments for use by researchers and clinicians who seek reliable methods to quantify the severity and impact of chronic pain in dogs with osteoarthritis.

Characterization of and factors associated with causes of pleural effusion in cats.

OBJECTIVE To characterize and investigate potential associations between causes of pleural effusion and various clinical factors in a large cohort of affected cats. DESIGN Retrospective case series with nested cross-sectional study. ANIMALS 380 client-owned cats with a diagnosis of pleural effusion from January 1, 2009, through July 14, 2014, for which the cause of pleural effusion had been fully investigated. PROCEDURES Electronic medical records were reviewed and data collected regarding cat characteristics, clinical signs, cause of pleural effusion, treatment, and survival status at discharge from the hospital. Variables were examined for associations with causes of pleural effusion. RESULTS 87 (22.9%) cats died or were euthanized before discharge from the hospital. Congestive heart failure (CHF) was the most common cause (155 [40.8%]) of pleural effusion, followed by neoplasia (98 [25.8%]). Other causes included pyothorax, idiopathic chylothorax, trauma, feline infectious peritonitis, and nontraumatic diaphragmatic hernia. Cats with trauma or feline infectious peritonitis were significantly younger than those with CHF or neoplasia. Cats with lymphoma were significantly younger than those with carcinoma. Cats with CHF had a significantly lower rectal temperature at hospital admission (mean ± SD, 36.9 ± 1.2°C [98.4 ± 2.2°F]) than did cats with pleural effusion from other causes (37.9 ± 1.2°C [100.2 ± 2.2°F]). CONCLUSIONS AND CLINICAL RELEVANCE Cats with pleural effusion in this study had a poor prognosis; CHF and neoplasia were common causes. Age and hypothermia may be helpful to raise the index of suspicion for certain underlying causes of pleural effusion in cats.

Short- and long-term outcomes after shoulder excision arthroplasty in 7 small breed dogs.

This study reports short- and long-term clinical outcomes following excision arthroplasty in 7 small breed dogs with shoulder pathology. Lameness and pain were scored before surgery, and reassessed at short- and long-term follow-ups with measurements of range of motion (ROM), scapulo-humeral angles of extension (EA) and flexion (FA), and muscle girth (MG) of the operated and contralateral limbs. All dogs improved clinically for lameness and pain. Range of motion, EA, and FA of the operated limb were not significantly different compared with the contralateral limb at short-term follow-up, but ROM and EA were significantly decreased at long-term examination. Muscle girth was not significantly different than the contralateral limb. Radiographic re-evaluations showed bony proliferation around osteotomies without interosseous union in most dogs and all owners were satisfied with the surgery outcome. Excision arthroplasty seems to be an effective treatment for chronic shoulder pathologies in small dogs. Range of motion and EA were decreased and a mild lameness remained present at long-term follow-up.

Évolution à court et à long terme suite à une arthroplastie d'épaule chez sept chiens de petite race. Cette étude rapporte l'évolution clinique à court et long terme suite à une arthroplastie d'excision chez sept chiens de petite race avec des anomalies de l'épaule. Les degrés de boiterie et de douleur ont été évalués avant la chirurgie et réévalués à court et à long terme avec l'amplitude de mouvement (ADM), les angles d'extension (AE) et de flexion (AF) de l'épaule, et le périmètre musculaire (PM) du membre opéré et du membre controlatéral. Tous les chiens se sont améliorés cliniquement concernant la boiterie et la douleur. Il n'y avait pas de différence significative entre l'ADM, AE et AF du membre opéré par rapport au membre controlatéral à court terme, par contre l'ADM et l'AE étaient significativement réduits à long terme. Le PM n'a pas changé de façon significative comparativement au membre controlatéral. Les réévaluations radiographiques ont montré une prolifération osseuse le long des traits d'ostéotomie sans évidence d'union interosseuse sur la majorité des chiens et tous les propriétaires ont été satisfaits du résultat de la chirurgie. L'arthroplastie d'excision semble être un traitement efficace des pathologies chroniques de l'épaule chez les petits chiens. Une diminution de l'ADM et l'AE et une légère boiterie restaient présents à long terme.(Traduit par les auteurs).

High-Definition Video Telescope-Assisted Ventral Slot Decompression Surgery for Cervical Intervertebral Disc Herniation in 30 Dogs.

OBJECTIVE: To describe the use of a video telescope operating monitor (VITOM™) for ventral slot decompression and to report its clinical applications using preoperative and postoperative computed tomography (CT) myelography. STUDY DESIGN: Prospective case series. ANIMALS: Consecutive dogs presented with cervical intervertebral disc disease requiring surgical decompression (n = 30). METHODS: Demographic data, preoperative neurological status, localization and lateralization of the compression, total operative time, surgical complications, ventral slot size and orientation, hospitalization time, and postoperative outcome were recorded. Preoperative and postoperative spinal cord area at the compression site and ratios of compressed to normal spinal cord area were calculated by CT myelography. RESULTS: French Bulldogs were the most common breed of dogs (n = 15; 50%) and neck pain was the most common neurological sign (n = 18; 60%). Postoperative CT myelography confirmed that spinal cord decompression, postoperative spinal cord area, and the ratios of compressed to normal spinal cord area improved significantly compared with preoperative measurements (P = .01). Sinus bleeding occurred in 20% of dogs. The mean ratios (± SD) of ventral slot length and width compared with vertebral body length and width were 0.21 ± 0.08 and 0.31 ± 0.07, respectively. The mean postoperative hospitalization time was 3.0 ± 0.6 days and all dogs showed clinical improvement and an excellent outcome. CONCLUSION: The VITOM™ ventral slot decompression technique was fast and easy to perform. It allowed a minimally invasive approach with a small ventral slot while improving spinal cord visualization. The results of this study support the use of the VITOM™ technique in spinal veterinary surgery.

Feasibility of Stifle Medial Meniscal Release in Toy Breed Dogs with and without a Joint Distractor.

OBJECTIVE: To investigate the feasibility of medial meniscal release (MMR) during stifle arthroscopy in toy breed dogs with and without a joint distractor. STUDY DESIGN: Experimental cadaveric study. SAMPLE POPULATION: Stifles (n = 40) from 20 canine cadavers (1.8-5.1 kg). METHODS: Paired stifles were randomly assigned to the joint distractor group and the control group (n = 20 each). All stifles underwent arthroscopic transection of the cranial cruciate ligament followed by a release of the caudomedial meniscotibial ligament. After the procedures, all stifles were disarticulated. The degree of released meniscus was recorded subjectively by 5% increments. A MMR success was defined as a complete transection. The areas of femoral and tibial articular cartilage damage were calculated using india ink staining and digital imaging. The results were compared between groups and odds ratios were calculated. RESULTS: All stifle arthroscopies were successful. The success rate of MMR was significantly higher (P = .013) with a joint distractor than without a joint distractor. MMR was 7.4 times more likely to succeed with a joint distractor than without a joint distractor. The distal femoral articular cartilage was significantly more damaged (P = .011) in the stifles without a joint distractor than in the stifles with a distractor. No difference was found between the 2 groups for damage to the tibial cartilage (P = .058). CONCLUSION: Stifle arthroscopic MMR is feasible in toy breed dogs. Using a joint distractor is recommended for arthroscopic treatment based on our results because it significantly reduced the rate of incomplete release as well as iatrogenic cartilage damage.

Evaluation of a Veress needle for the fluid egress system of stifle arthroscopy in toy dog breeds.

OBJECTIVES: The aim of this study was to evaluate the use of a Veress needle as a fluid egress system for stifle arthroscopy in toy dog breeds. METHODS: Cadaveric canine stifle joints (n = 32) were prepared to induce an artificial intra-articular haemorrhagic effect, followed by stifle arthroscopy. The stifles were randomly assigned to one of three groups, and a fluid egress portal was established using a Veress needle (VN), a standard egress cannula (SE), or an intravenous catheter stylet (CS). Time to establish the egress portal, arthroscopic visibility, and egress portal performance were evaluated during the arthroscopy. After the arthroscopic examinations, iatrogenic cartilage lesions were identified and analysed using the percentage area of cartilage damage (%ACD). RESULTS: The overall arthroscopic visibility and egress portal performance were not significantly different among the groups. The egress portal establishment was faster for the VN (33 sec) and the CS (34 sec) groups than for the SE (43 sec) group (p = 0.001). On gross joint examination, no iatrogenic laceration was found in the VN group, whereas four out of 10 of the SE and two out of 10 of the CS specimens had linear cartilage excoriation on the stifle joints. The %ACD score of the VN group was lower than those of the SE group (p = 0.009) and the CS group (p = 0.001). CLINICAL SIGNIFICANCE: The Veress needle method used in this study was useful to establish a fluid egress system and limit iatrogenic cartilage excoriations. This technique could become the method of choice for stifle arthroscopy, especially in smaller dogs.

Short- and long-term outcomes after arthroscopic treatment of young large breed dogs with medial compartment disease of the elbow.

OBJECTIVES: To report short- and long-term outcomes after arthroscopic treatment in young large breed dogs affected by medial coronoid process disease (MCPD) and identify variables affecting outcome. STUDY DESIGN: Prospective observational case series. ANIMALS: Large breed dogs <3 years old (n = 15; 23 elbows). METHODS: MCPD was confirmed by radiography, computed tomography, and arthroscopy. Dogs were treated by arthroscopy. Variables recorded at time of treatment included radioulnar incongruity (RUI) and degree of cartilage erosion. Variables recorded before, 6 weeks, and ≥23 months after surgery included radiographic score for osteoarthritis, trochlear notch sclerosis, muscle circumference, range of motion (ROM), and the load distribution of vertical ground reaction forces between thoracic and pelvic limbs. RESULTS: A greater load distribution to the pelvic limbs was identified preoperatively in dogs with RUI than in dogs with congruent elbows. Load distribution was not significantly improved at 6 weeks compared with preoperatively. Muscle circumference and vertical impulse distributions were improved at long-term evaluation despite an increased osteoarthritis score. This improvement was more obvious in dogs with RUI or a high degree of cartilage erosion at initial presentation. CONCLUSION: Some evidence of improvement in long-term function was found in dogs with MCPD after arthroscopic treatment. RUI and cartilage erosion at the time of diagnosis were associated with more lameness preoperatively but did not affect the final gait assessment or osteoarthritis score in this small cohort.

Knot security and tensile strength of suture materials.

OBJECTIVE: To evaluate knot security and tensile failure load of suture tied in simple interrupted, beginning continuous, and ending continuous patterns for 11 suture materials commonly used in small animal surgery. STUDY DESIGN: Mechanical study. METHODS: For each of 11 suture material types, and 5 knot sizes (2, 3, 4, 5, and 6 throws) 2 surgeons each tied 6 knots (n = 12 for each knot size in 11 suture materials). Three types of patterns were evaluated: a simple interrupted square knot, a square knot beginning a simple continuous pattern, and the knot ending a simple continuous pattern. All knots were incubated in healthy canine donor plasma at 40°C for a minimum of 24 hours. Sutures were evaluated for knot security (knots untied, suture failed by breaking, suture slipped from the clamps, or suture untied before testing) and maximum load carried before knot slippage or knot failure (termed tensile failure load). RESULTS: Significant differences were found in knot security and tensile failure load among suture types. There was no significant difference between the simple interrupted knots and the knots at the beginning of a simple continuous pattern; however, both were significantly less likely to fail than the knots tied at the end of a simple continuous pattern. The number of throws per knot had a significant effect for knot security and tensile failure load. Surgeon experience had a significant effect on failure mode and tensile failure load. CONCLUSIONS: Suture type, number of throws per knot (knot size), suture pattern, and surgeon experience play an important role in knot security and should be considered when performing surgery.

Effect of using triclosan-impregnated suture for incisional closure on surgical site infection and inflammation following tibial plateau leveling osteotomy in dogs.

OBJECTIVE: To compare surgical site infection and inflammation rates between the use of nonimpregnated (polydioxanone and poliglecaprone 25) versus triclosan-impregnated (polydioxanone and poliglecaprone 25) suture for incisional closure in dogs undergoing a standardized orthopedic procedure (tibial plateau leveling osteotomy [TPLO]). DESIGN: Retrospective cohort study. ANIMALS: 283 dogs that underwent TPLO between November 2005 and December 2009. PROCEDURES: Medical records were reviewed for age; body weight; body condition score; use of propofol; perioperative and postoperative administration of antimicrobials; presence of a preoperative infection; use of a jig; technique of joint exploration; type of suture material (triclosan impregnated vs nonimpregnated) used to close the pes anserinus, subcutaneous layer, and subcuticular layer; use of staples or suture to close the skin; and surgery and anesthesia durations. The outcome variables were surgical site inflammation and infection. RESULTS: Rates of infection and inflammation did not differ between surgeries for which triclosan-impregnated suture was used (n = 159 [8.8%, and 18.8%, respectively]) and those for which nonimpregnated suture was used (112 [10.7% and 15.2%, respectively]). The use of staples, compared with suture, to close the skin significantly decreased the inflammation rate. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with in vitro conditions, in vivo conditions (where the environment is not controlled and triclosan may elute more quickly from the suture) may decrease the antibacterial effectiveness of triclosan-impregnated suture. On the basis of our findings, triclosan-impregnated sutures did not seem to provide an additional benefit for clinical use and cannot be strongly recommended for elective orthopedic procedures in veterinary medicine.

Septic peritonitis: etiology, pathophysiology, and diagnosis.

Septic peritonitis is an inflammatory condition of the peritoneum that occurs secondary to microbial contamination. This clinically important condition has a wide variety of clinical courses as well as high morbidity and mortality due to secondary multiorgan dysfunction. This article reviews the etiology and pathophysiology of this condition and its diagnosis in small animals; a companion article addresses treatment and prognosis.

Septic peritonitis: treatment and prognosis.

Septic peritonitis is an inflammatory condition of the peritoneum that has a wide variety of clinical courses. The etiology and pathophysiology of this condition and its diagnosis in small animals are reviewed in a companion article. This article addresses the treatment of septic peritonitis and prognosis in small animals.

Clinical and histologic effects of intracardiac administration of propofol for induction of anesthesia in ball pythons (Python regius).

OBJECTIVE: To assess the clinical differences between induction of anesthesia in ball pythons with intracardiac administration of propofol and induction with isoflurane in oxygen and to assess the histologic findings over time in hearts following intracardiac administration of propofol. DESIGN: Prospective randomized study. ANIMALS: 30 hatchling ball pythons (Python regius). PROCEDURES: Anesthesia was induced with intracardiac administration of propofol (10 mg/kg [4.5 mg/lb]) in 18 ball pythons and with 5% isoflurane in oxygen in 12 ball pythons. Induction time, time of anesthesia, and recovery time were recorded. Hearts from snakes receiving intracardiac administration of propofol were evaluated histologically 3, 7, 14, 30, and 60 days following propofol administration. RESULTS: Induction time with intracardiac administration of propofol was significantly shorter than induction time with 5% isoflurane in oxygen. No significant differences were found in total anesthesia time. Recovery following intracardiac administration of propofol was significantly longer than recovery following induction of anesthesia with isoflurane in oxygen. Heart tissue evaluated histologically at 3, 7, and 14 days following intracardiac administration of propofol had mild inflammatory changes, and no histopathologic lesions were seen 30 and 60 days following propofol administration. CONCLUSIONS AND CLINICAL RELEVANCE: Intracardiac injection of propofol in snakes is safe and provides a rapid induction of anesthesia but leads to prolonged recovery, compared with that following induction with isoflurane. Histopathologic lesions in heart tissues following intracardiac injection of propofol were mild and resolved after 14 days.

A comparative study of seeding techniques and three-dimensional matrices for mesenchymal cell attachment.

Mesenchymal stem cells (MSCs) offer significant potential as a cell source in tissue-engineering applications because of their multipotent ability. The objective of this study was to evaluate the behaviour of MSCs during the seeding phase, using four different seeding techniques (spinner flask, custom vacuum system combined with a perfused bioreactor or with an orbital shaker, and orbital shaker) with four different scaffold materials [polyglycolic acid, poly(lactic acid), calcium phosphate and chitosan-hyaluronic acid]. Scaffolds were selected for their structural and/or chemical similarity with bone or cartilage, and characterized via scanning electron microscopy (SEM) and measurement of fluid retention. Cell attachment was compared between seeding techniques and scaffolds via cell-binding kinetics, cell viability and DNA quantification. SEM was used to evaluate cell distribution throughout the constructs. We discovered from cell suspension kinetics and DNA data that the type of loading (i.e. direct or indirect) mainly influences the delivery of cells to their respective scaffolds, and that dynamic seeding in a spinner flask tended to improve the cellularity of polymer constructs, especially mesh. Regardless of the seeding method, bone marrow-derived MSCs displayed a superior affinity for calcium phosphate scaffolds, which may be related to their hydrophobicity. MSCs tended to aggregate into flat sheets, occluding the external pores of matrices and affecting cell distribution, regardless of seeding technique or scaffold. Taken together, these results provide insight into the design of future experiments using MSCs to engineer functional tissue.

Effect of collagen II coating on mesenchymal stem cell adhesion on chitosan and on reacetylated chitosan fibrous scaffolds.

The biocompatibility and biomimetic properties of chitosan make it attractive for tissue engineering but its use is limited by its cell adhesion properties. Our objectives were to produce and characterize chitosan and reacetylated-chitosan fibrous scaffolds coated with type II collagen and to evaluate the effect of these chemical modifications on mesenchymal stem cell (MSC) adhesion. Chitosan and reacetylated-chitosan scaffolds obtained by a wet spinning method were coated with type II collagen. Scaffolds were characterized prior to seeding with MSCs. The constructs were analyzed for cell binding kinetics, numbers, distribution and viability. Cell attachment and distribution were improved on chitosan coated with type II collagen. MSCs adhered less to reacetylated-chitosan and collagen coating did not improve MSCs attachment on those scaffolds. These findings are promising and encourage the evaluation of the differentiation of MSCs in collagen-coated chitosan scaffolds. However, the decreased cell adhesion on reacetylated chitosan scaffold seems difficult to overcome and will limit its use for tissue engineering.

Evaluation of intra- and interobserver variability and repeatability of tibial plateau angle measurements with digital radiography using a novel digital radiographic program.

OBJECTIVE: To compare the intra- and interobserver variability occurring when observers with differing experience levels measure tibial plateau angles (TPAs) with a novel digital radiographic projection program (tibial plateau leveling osteotomy [TPLO] planning program), the Kodak Picture Archiving and Communications System (PACS), and standard sized printed films (SF). STUDY DESIGN: Cross-sectional study. SAMPLE POPULATION: Dogs (n=36) with cranial cruciate ligament (CCL) rupture that had a TPLO. METHODS: Six observers, divided into 3 equal groups based on experience level, measured TPA on 36 digitally captured radiographic images of tibiae of dogs clinically affected with CCL rupture. Each observer used 3 methods of measuring TPA and repeated the measurements 3 times with each method. The intra- and interobserver variability was compared using the coefficient of variation. RESULTS: Averaged over all replications and images, there was no significant difference (P>.05) in the average variability occurring with each method for all but 1 observer. There was no effect of experience level on measurement variability; however, interobserver variability was significantly less with measurements made with the PACS and TPLO planning program compared with measurements made from SF (P<.05). CONCLUSIONS: Repeated measurements of TPA made using digital images and computer-based measurement programs were significantly less variable between observers than those made from images printed on standard radiographic films. CLINICAL RELEVANCE: Digital radiography and computer-based measurement programs are effective for determining the TPA, allowing less variability in measurements compared with SF. The ability to manipulate the image may allow better identification of anatomic landmarks.

Effect of chitosan scaffold microstructure on mesenchymal stem cell chondrogenesis.

Although numerous biomaterials have been investigated as scaffolds for cartilage tissue engineering, the effect of their microstructure on final construct characteristics remains unclear. The biocompatibility of chitosan and its similarity with glycosaminoglycans make it attractive as a scaffold for cartilage engineering. Our objective was to evaluate the effect of chitosan scaffold structure on mesenchymal stem cell proliferation and chondrogenesis. Chitosan fibrous scaffolds and chitosan sponges were seeded with mesenchymal stem cells in a chondrogenic medium. Constructs were analyzed 72 h after seeding via scanning electron microscopy (SEM), weight measurements and DNA quantification. Constructs were cultured for 10 or 21 days prior to confocal microscopy, SEM, histology, quantitative analysis (weight, DNA and glycosaminoglycan (GAG)), and quantitative real-time polymerase chain reaction. Mesenchymal stem cells maintained a viability above 90% on all chitosan scaffolds. The cell numbers in the constructs were similar at 72 h, 10 days and 21 days. However, matrix production was improved in chitosan fibrous constructs based on the GAG quantification and collagen II mRNA expression. Chondrogenesis on chitosan scaffolds is superior on microfibers compared to macroporous sponges.

Cartilage tissue engineering on fibrous chitosan scaffolds produced by a replica molding technique.

The biocompatibility of chitosan and its similarity with glycosaminoglycans make it attractive as a scaffold for cartilage engineering. Fibrous scaffolds may simulate cartilage extracellular matrix structure and promote chondrocyte functions. Our objectives were to produce chitosan fibers of different size and evaluate their potential for chondrogenesis. A novel replica molding technique was developed to produce chitosan nonwoven scaffolds made of fiber measuring 4, 13, or 22 mum in width. A polyglycolic acid mesh (PGA) served as a reference group. Controls were analyzed 48 h after seeding porcine chondrocytes via scanning electron microscopy (SEM), DNA, and glycosaminoglycan (GAG) quantifications. Constructs were cultured for 21 days prior to confocal microscopy, SEM, histology, and quantitative analysis (weight, water, DNA, GAG and collagen II). Chondrocytes maintained their phenotypic appearance and a viability above 85% on the chitosan scaffolds. Chondrocytes attach preferentially to PGA, resulting in a greater cellularity of these constructs. However, based on the GAG/DNA and Collagen II/DNA ratios, matrix production per chondrocyte was improved in chitosan constructs, especially on smaller fibers. The differences between PGA and chitosan are more likely to result from the chemical composition rather than their structural characteristics. Although chitosan appears to promote matrix formation, further studies should be aimed at improving its cell adhesion properties.

Bilateral iliopsoas muscle contracture and spinous process impingement in a German Shepherd dog.

OBJECTIVE: To report diagnosis and treatment of bilateral iliopsoas muscle contracture in a dog with spinous process impingement. STUDY DESIGN: Case report. ANIMALS: German Shepherd dog. METHODS: A dog with chronic progressive lameness, flexion contracture of the coxofemoral joints, severe pain, and decreased femoral reflexes had severe spondylosis bridging the vertebral bodies from L1 to L4 and enlarged dorsal spinous processes from T8 to L6 with impingement and bony proliferation. Ultrasonographic and magnetic resonance imaging (MRI) findings were consistent with fibrosis, mineralization, and atrophy of the iliopsoas muscles bilaterally which was treated by staged tenectomy of the insertions of the iliopsoas muscles. RESULTS: Because of severe perivascular fibrosis, the femoral vessels required ligation. Bilateral iliopsoas muscle tenectomy improved gait and provided pain relief. Histologic findings were consistent with fibrotic myopathy. CONCLUSIONS: Slow progression of severe clinical signs observed bilaterally in this dog differs from previous reports of iliopsoas myopathy. Findings were similar to the fibrotic myopathy of the gracilis or semitendinosus muscles described in dogs. CLINICAL RELEVANCE: Iliopsoas muscle abnormalities should be considered in dogs with limited hip extension and pain. MRI is useful for diagnosing muscle fibrosis. Iliopsoas tenectomy may improve clinical function in dogs with fibrotic myopathy.