Liverpool Osteoarthritis In Dogs Research Articles

Bilateral locking compression plate and transcondylar screw fixation for stabilization of canine bicondylar humeral fractures

To report the surgical management, complications, and short-term outcomes for dogs with humeral Y-T fractures (ie, fractures affecting the medial and lateral aspect of the humeral condyle extending from the articular surface) that had been approached bilaterally (medial and lateral) and stabilized with two locking compression plates (LCP) and to investigate risk factors for major complications in the short term. Retrospective case series. Twenty-eight client-owned dogs. Medical records of 28 dogs that presented with 29 consecutive Y-T fractures that had been approached bilaterally, reduced, and stabilized by using a transcondylar screw (in lag or positional fashion) and two or three LCP were reviewed. All dogs had at least 6 weeks clinical follow-up, and in some cases, responses from the long-term owner-based University of Liverpool questionnaire for owners of dogs with mobility problems (Liverpool Osteoarthritis in Dogs) was obtained. Twenty-eight dogs (29 fractures) presented with Y-T fractures and met the inclusion criteria. The fractures were reduced and stabilized with bilateral LCP and screws. The French bulldog (n = 7) was the most commonly represented breed. Age ranged from 4 months to 9.5 years (mean, 43.53 ± 34.63 months); seven (25%) dogs were considered skeletally immature. Twenty-seven (96.4%) dogs were considered to have had resolution of lameness at 6 weeks. Major complications were registered in two (7%) dogs; one dog required surgical revision, and one dog had catastrophic complications leading to amputation of the limb. The owner-based questionnaire was available for 18 (64%) dogs. Management of canine Y-T humeral fractures stabilized with bilateral LCP and transcondylar screws led to a low complication rate with a good to excellent long-term outcome according to responses on the client questionnaire. Risk factors for major complications were not identified in our sample population. Management of Y-T humeral fractures stabilized with bilateral LCP and transcondylar screws can lead to good to excellent short-term outcome with a low complication rate in mature and immature dogs.

A report on the use of a single intra-articular administration of autologous platelet therapy in a naturally occurring canine osteoarthritis model - a preliminary study

BackgroundOsteoarthritis (OA) represents a significant burden to societies, as it affects quality of life, performance and poses a large healthcare cost. We aimed to describe the use of a single intra-articular (IA) injection of an autologous platelet therapy in the management of osteoarthritis (OA) in a naturally occurring canine model.MethodsFifteen police working dogs with bilateral hip OA were treated with 3 ml of platelet concentrate per hip joint, produced with the V-PET kit. Response to treatment was measured by the Canine Brief Pain Inventory (CBPI, divided in pain interference score – PIS, and Pain Severity Score - PSS), Liverpool Osteoarthritis in Dogs (LOAD), Canine Orthopedic Index (COI, divided in four dimensions: function, gait, stiffness and quality of life - QOL) and the Hudson Visual Analogue Scale (HVAS). Seven different time points were considered: T0 (before treatment), T1 (after 15 days), T2, T3, T4, T5 and T6 (after 1, 2, 3, 4 and 5 months respectively). Results from each evaluation moment were compared with T0 with a Paired Samples T-Test, and a p < 0.05 was set.ResultsSignificant differences were observed at T1 (p < 0.01 for HVAS, PSS, COI, Gait and QOL; p = 0.01 for PIS; p = 0.02 for Function; and p < 0.05 for Stiffness), T2 (p < 0.01 for PSS, PIS and Gait; p = 0.01 for COI; p = 0.02 for HVAS, Function and QOL; and p = 0.04 for Stiffness), T3 (p < 0.01 for HVAS, PSS, PIS, Function and Gait; p = 0.01 for COI; and p = 0.02 for QOL), T4 (p < 0.01 for PSS; p = 0.03 for PIS and Gait), T5 (p < 0.01 for COI, Function and Gait; p = 0.03 for PSS, PIS and Stiffness), T6 (p < 0.01 for PSS, Function and Gait; p = 0.04 for PIS; p < 0.05 for COI) and T7 (p < 0.01 for PSS, Function and Gait; p = 0.01 for COI; and p < 0.05 for PIS).ConclusionsAutologous platelet therapy was used without apparent harm in the subjects. A single administration produced significant improvements, which lasted several months, and therefore warrants further study.

Elevated Synovial Fluid Concentration of Monocyte Chemoattractant Protein-1 and Interleukin-8 in Dogs with Osteoarthritis of the Stifle.

Chemokines such as monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) have been shown to cause monocyte and natural killer cell chemotaxis and polymorphonuclear cell chemotaxis, respectively. Additionally, MCP-1 signalling has been implicated in modulating pain. Elevated synovial fluid concentrations of MCP-1 and IL-8 have been demonstrated in humans with osteoarthritis, but currently there are no studies evaluating synovial MCP-1 or IL-8 concentrations in dogs. Additionally, there are no canine studies evaluating the correlation between these chemokines and caregiver perceived pain and mobility, as measured by the clinical metrology instrument, Liverpool Osteoarthritis in Dogs. This study documented elevated synovial fluid concentrations of IL-8 and MCP-1 in the stifle of dogs with secondary osteoarthritis compared with normal stifles. However, this study found no correlation between MCP-1 or IL-8 and Liverpool Osteoarthritis in Dogs or radiographic severity of osteoarthritis.

Evaluation of the Effects of Undenatured Type II Collagen (UC-II) as Compared to Robenacoxib on the Mobility Impairment Induced by Osteoarthritis in Dogs.

Osteoarthritis (OA) is a chronic disease that requires a multimodal therapeutic approach. The aim of this study was to evaluate the effects of undenatured type II collagen (UC-II) as compared to robenacoxib in dogs affected by OA. Our hypothesis was that the two compounds would be similar (non-inferiority) in improving mobility. To test this hypothesis, a complete orthopedic examination, x-ray and the Liverpool Osteoarthritis in Dogs (LOAD) survey were performed in dogs affected by OA before and after the treatments. The study was designed as a clinical, randomized, controlled and prospective study. Sixty client-owned dogs were randomized in the R group (n = 30, robenacoxib 1 mg/kg/day for 30 days) and in the UC-II group (n = 30, UC-II 1 tablet/day for 30 days). Thirty days after the beginning of the treatment (T30), the dogs were reassessed for the LOAD, MOBILITY and CLINICAL scores. Based on the data obtained from the study, a significant reduction in LOAD and MOBILITY scores was recorded between T0 and T30 with a similar magnitude among the two groups (R = 31.5%, p < 0.001; UC-II = 32.7%, p = 0.013). The results of this study showed that UC-II and robenacoxib were able to similarly improve mobility of dogs affected by OA.

Correlation of serum and synovial leptin concentrations with body condition scores in healthy and osteoarthritic dogs.

To evaluate the relationship between serum and synovial fluid (SF) leptin concentrations and body condition score (BCS) in healthy and osteoarthritic dogs. Controlled, prospective, clinical study. Nineteen healthy dogs and 29 dogs with osteoarthritis (OA) secondary to cranial cruciate ligament injury. Synovial fluid was obtained from the femorotibial joint under sedation (healthy dogs) or during surgery (OA dogs). Serum and SF leptin and interleukin (IL)-1β concentrations were measured via enzyme-linked immunosorbent assay. Dogs were classified as optimal weight (BCS 4-5/9) or overweight (BCS >5/9). Radiographs were scored for OA severity by a radiologist. Owners completed the Liverpool Osteoarthritis in Dogs (LOAD) questionnaire. Mean (± SD) SF leptin (4.09 ± 4 ng/mL) was lower than serum leptin (6.88 ± 5.52 ng/mL, P < .0001). Synovial fluid leptin was higher in overweight (5.28 ± 4.21) than in optimal body weight dogs (1.54 ± 1.72 ng/mL, P < .0001). Serum (P < .001) and SF leptin (P = .004) concentrations were associated with BCS. Concentration of SF leptin did not differ between healthy (2.4 ± 2.04 ng/mL) and OA (4.9 ± 4.3 ng/mL, P = .25) dogs. Synovial fluid leptin and LOAD scores were weakly associated (P = .03). No association was detected between SF leptin and radiographic score or IL-1β (P = .73). Serum and SF leptin correlated with BCS in this population. Synovial fluid leptin was weakly associated with LOAD scores but not with radiographic severity of OA or IL-1β. Serum and SF leptin concentrations do not predict radiographic severity of canine OA but contribute to joint pain and dysfunction.

Synthetic osteochondral resurfacing for treatment of large caudocentral osteochondritis dissecans lesions of the humeral head in 24 dogs.

To report the outcome of dogs with large, caudocentral, osteochondritis dissecans (OCD) lesions of the humeral head treated with synthetic osteochondral resurfacing (SOR) implants. Retrospective case series. Twenty-four client-owned large breed or giant dogs. The medical records of all dogs treated with first generation (G1) and second generation (G2) SOR implants were reviewed. All dogs were assessed with clinical examination and imaging 12 weeks after surgery. Assessment of outcome was based on subjective assessment of lameness, scoring of postoperative radiographs, and the Liverpool Osteoarthritis in Dogs (LOAD) questionnaire. Osteochondral resurfacing was performed with a G1 implant in 13 dogs (15 shoulders) and a G2 implant in 11 dogs (13 shoulders). Lameness resolved in all dogs treated with G1 implants and in 10 dogs treated with G2 implants by 12 weeks after surgery. One dog treated with a G2 implant was found to have an implant-associated infection, requiring implant removal. No recurrence of lameness was reported in 9 limbs treated with G1 implants and 10 limbs treated with G2 implants that were available for clinical review at a median time of 387 and 365 days, respectively, after surgery. Mean postoperative LOAD scores were 4.2 of 52 and 5.2 of 52 in dogs treated with a G1 or a G2 implant, respectively. Synthetic resurfacing was technically feasible in all joints of this study and resulted in good clinical results. The use of SOR implants seems viable to treat large caudocentral OCD lesions of the humeral head in dogs and warrants prospective comparison with conventional arthroscopic treatment.

Correlation of synovial fluid leptin with body habitus in the healthy and osteoarthritic canine knee

Purpose: Naturally occurring cranial cruciate ligament (CrCL) insufficiency and progressive osteoarthritis (OA) are common in the canine population and can serve to provide useful information to understand both canine and human knee joint disease. Leptin, an adipocytokine, has been shown to be proportional to adipose mass. In humans, leptin has been associated with radiographic progression of knee OA, markers of cartilage damage, and pain in osteoarthritic knees. The primary goal of this study is to evaluate the relationship between serum and synovial fluid (SF) leptin and body condition score and body fat percentage in dogs. The secondary goal was to characterize the relationship between SF leptin and markers of inflammation, such as IL-1β Methods: Forty-eight client-owned dogs, 19 healthy controls and 29 with secondary OA, were enrolled. Any dog with evidence of systemic disease, based on physical exam and routine hematology was excluded from the study. Informed owner consent was obtained and all procedures were approved by the Clinical Research Committee. Sample Collection - Dogs in the control group were sedated and a single femorotibial joint was randomly selected for arthrocentesis. Synovial fluid was collected using aseptic technique. For dogs in the OA group, SF was obtained intra-operatively from the affected limb prior to arthrotomy for correction of CrCL insufficiency. Blood was collected via standard jugular venipuncture. Morphometric Measures - Body condition score, BCS, was determined on a standard 9-point scalea by 3 individual observers, who were unaware of the other raters’ score. Dogs were then divided into to 2 groups, optimal weight (BCS 4-5) and overweight (BCS >5). Additionally trunk and limb measurements were obtained to calculate body fat percentage, as previously reported1. Osteoarthritis Severity Scoring- In the OA group, radiographs were scored for severity of OA by a radiologist utilizing a previously described scoring system2. Owners were required to fill out a clinical metrology questionnaire (Liverpool Osteoarthritis in Dogs, LOAD). Sample Analysis - Canine specific leptinb and IL-1βc ELISAs were used to measure SF and serum leptin and IL-1β. Data Analysis - Student t-tests were used to test for differences in SF leptin means due to CrCL status, presence of SF or serum IL-1β, and the potential confounder non-steroidal anti-inflammatory (NSAID) use. Linear regressions were used to test for association of synovial leptin with BCS, body fat percent, serum leptin concentration, LOAD, and radiographic score. Multiple linear regression was also used to adjust the linear model for the association of synovial leptin and OA status for BCS. Results: SF leptin was significantly lower than serum leptin (p<0.01) and there was a 5.8ng/mL change in SF leptin for every 10ng/ml increase in serum leptin. Overweight dogs had significantly higher concentration of SF leptin than those that were optimal body weight (p<0.01). SF leptin concentration was associated with both BCS and body fat % (p<0.01). For every 1unit increase in BCS there was a 1.7ng/mL increase in SF leptin and for every 10% increase in body fat, there was a 2.7ng/mL increase in SF leptin. Synovial fluid leptin was significantly higher in dogs with OA by a mean amount of 2.8 (95% CI 0.6-5.1) but this difference decreased and became no longer significant when adjusted for differences in body condition score between OA groups (p=0.25). There was a weak association between SF leptin and LOAD; for every 1ng/mL increase in leptin a 10unit increase in LOAD was observed (R2=0.100; p=0.03). There was no significant association between SF leptin and radiographic score (p=0.24), SF IL-1β (p=0.64) or NSAID use (p=0.55). Conclusions: This is the first study to document the presence of leptin in canine SF. As expected, SF leptin was positively correlated with serum leptin and measures of body habitus. However, SF leptin levels in dogs with CrCL insufficiency were not significantly different from control dogs. Still, there was weak positive association between SF leptin and LOAD, in dogs with OA. As all these dogs had CrCL insufficiency at the time of data collection, the pain and dysfunction from joint instability may have masked small changes due to chronic OA and contributed to the weak nature of this link. The results of this study did not correlate leptin levels with severity of OA, or local concentrations of IL-1β. In the canine model of OA, obesity related OA severity may be related to other adipokines or may purely be biomechanical in nature. Further studies are needed in both people and dogs to determine the role of leptin in OA.

Influence of class IV laser therapy on the outcomes of tibial plateau leveling osteotomy in dogs.

To determine the effects of low-level laser therapy (LLLT) on clinical outcomes in dogs with cranial cruciate ligament disease treated with tibial plateau leveling osteotomy (TPLO). Randomized, placebo-controlled clinical trial. Owners and surgeons (care providers and assessors) were masked. Ninety-five dogs were admitted for TPLO and assigned to 1 of 2 groups, laser group (LG; n = 51) or placebo group (PG; n = 44). Three treatments (laser or placebo) were administered within a 4-day perioperative period. A fourth treatment was recommended and was accepted in 28.4% of cases (LG, n = 14; PG, n = 13). Dogs in the LG group received laser at wavelengths 660 nm red (100 mW) and at 800, 905 and 970 nm infrared (maximum 15 W continuous wave, 20 W peak pulsed wave), administered simultaneously. Dogs in the PG group received placebo laser (660 nm, 4 mW). Other treatments were identical. Outcomes were measured by difference in clinical metrology instruments (Liverpool Osteoarthritis in Dogs and adjusted Canine Orthopedic Index [COI]), osteotomy healing on a radiographic scale, time to cessation of nonsteroidal anti-inflammatory drug administration, and wound healing by owner questionnaire. The only difference detected between groups consisted of a greater improvement in the gait section of the adjusted COI (ACOI) in the LG group (median [interquartile range; IQR] = 6 [4-7.5]) compared with the PG group (median [IQR] = 4 [2-6]; P < .05). The laser protocol used in this study was associated with a greater improvement in ACOI gait in dogs treated with TPLO but did not improve any other clinical metrology instrument scores or bone healing. This study provides some evidence that LLLT may improve the gait of dogs recovering from a TPLO, as assessed by owners.

Treatment of tibial diaphyseal fractures following plateless tibial tuberosity advancement to manage cranial cruciate disease.

To report diaphyseal fractures of the proximal tibia following tibial tuberosity advancement without plate stabilisation for the management of cranial cruciate ligament rupture in dogs. Members of the British Veterinary Orthopaedic Association's online discussion forum were invited to submit revision cases of tibial diaphyseal fracture following tibial tuberosity advancement without plate fixation. Data collected included signalment, surgical revision technique, pre- and postoperative revision radiographic findings, complications and veterinary assessment. Owners were invited to complete the Liverpool Osteoarthritis in Dogs questionnaire. A total of 17 dogs were included in the study. Eleven dogs had OrthoFoam-wedge modified Maquet procedures and six had the tibial tuberosity advancement rapid procedure. Tibial tuberosity advancement was maintained in 14/17 cases. Postrevision surgery complications occurred in eight cases: minor complications in 3/17 dogs; major in 5/17 and no catastrophic complications. Surgical site infection was the most common complication (4/8). Final clinical outcome found 8/17 of dogs to have excellent, 8/17 satisfactory and 1/17 poor clinical outcome. The median Liverpool Osteoarthritis in Dogs score was 12/52 (range 2 to 28). Final outcome was 6/13 owners that were very satisfied, 2/13 owners indifferent and 5/13 owners very disappointed. This is the first case series reporting tibial diaphyseal fractures following tibial tuberosity advancement without plate stabilisation. The authors report here a wide spectrum of potential fixation strategies should one of these fractures occur.

TTA-Rapid in the treatment of the canine cruciate deficient stifle: short- and medium-term outcome.

To evaluate complications, short- and medium-term outcomes following treatment of lameness associated with cranial cruciate ligament insufficiency in dogs using the "TTA-Rapid" technique. Patient records from two veterinary clinics were retrospectively examined to collect data from cases treated over a period of 21 months. An owner postal questionnaire using a clinical metrology instrument (Liverpool Osteoarthritis in Dogs) evaluated medium-term outcome of at least six months. In total 152 procedures were carried out in 141 dogs by two surgeons. Major complications, requiring further intervention, were identified in 11 (7%). Nine of these involved "late" meniscal injuries and two sustained tibial fractures postoperatively, one requiring internal fixation and the other external coaptation. The 3-month outcome was considered satisfactory in 99% of 135 procedures whilst the medium-term outcome (mean 16 months) was considered satisfactory in 86% of 108 dogs. "TTA-Rapid" offers a treatment option for cranial cruciate-deficient stifles with good short- and medium-term outcomes. The complication rate was low in our hands.

Client-assessed long-term outcome in dogs with surgical site infection following tibial plateau levelling osteotomy

The objective of this study was to describe client-assessed long-term functional outcome following surgical site infection (SSI) in dogs that underwent tibial plateau levelling osteotomy (TPLO) and identify predictive factors...

Radiographic, Surgeon and Owner Assessment of the BioMedtrix TATE(®) Elbow Arthroplasty.

To report the long-term radiographic and clinical outcome of the BioMedtrix TATE elbow arthroplasty system in dogs. Assessment was via radiographs, a surgeon-based questionnaire, and owner assessment of outcome using the Liverpool osteoarthritis in dogs (LOAD) and canine brief pain inventory (CBPI) questionnaires. Retrospective multicenter, case series. Client-owned dogs undergoing TATE elbow arthroplasty. Questionnaires were distributed to surgeons in the United Kingdom performing TATE elbow arthroplasty and to the owners of the dogs operated on. Owners completed the LOAD and CBPI questionnaires. All completed questionnaires from surgeons and owners, and radiographs of the dogs were collated and analyzed. Surgeon questionnaires and radiographs were obtained for 33 elbows from 32 dogs, with owner questionnaires obtained for 19 dogs. Perioperative, short-term, and mid-term complication rates were 60%, 15%, and 15%, respectively. Radiographic assessment of component alignment showed 62% of cartridges were valgus or varus malaligned and 56% of cartridges were either translated medially or laterally relative to the long axis of the ulnar. There was no significant association between component alignment and final clinical outcome. Surgeon assessment reported 24% of dogs to have full, 52% acceptable, and 24% unacceptable outcome. Owner assessment showed significant decreases in pain severity and pain interference from preoperative to final status but no change in mobility scores. A high complication rate and variability in component placement was recorded with TATE athroplasty. However, component malalignment did not negatively impact clinical outcome. Final clinical outcome was favorable for most cases with significant reductions in pain severity and interference scores despite no changes in mobility scores.

Guidelines for recognition, assessment and treatment of pain: WSAVA Global Pain Council members and co-authors of this document:.

Karol Mathews DVM DVSc DACVECC (Canada) Peter W Kronen Dr Vet Med, DVM DECVAA (Switzerland) Duncan Lascelles BSc BVSc PhD DSAS DECVS DACVS MRCVS (USA) Andrea Nolan MVB DVA PhD DECVAA DECVPT MRCVS (UK) Sheilah Robertson BVMS (Hons) PhD DACVAA DECVAA DECAWBM (WSEL) DACAW MRCVS (USA) Paulo VM Steagall MV MS PhD DACVAA (Brazil/Canada) Bonnie Wright DVM DACVAA (USA) Kazuto Yamashita DVM MS PhD DJCVS (Japan)

Evaluation of Construct and Criterion Validity for the ‘Liverpool Osteoarthritis in Dogs’ (LOAD) Clinical Metrology Instrument and Comparison to Two Other Instruments

ObjectiveTo test the ‘Liverpool Osteoarthritis in Dogs’ (LOAD) questionnaire for construct and criterion validity, and to similarly test the Helsinki Chronic Pain Index (HCPI) and the Canine Brief Pain Inventory (CBPI).DesignProspective Study.Animals222 dogs with osteoarthritis.ProcedureOsteoarthritis was diagnosed in a cohort of dogs on the basis of clinical history and orthopedic examination. Force-platform analysis was performed and a “symmetry index” for peak vertical force (PVF) was calculated. Owners completed LOAD, CBPI and HCPI instruments. As a test of construct validity, inter-instrument correlations were calculated. As a test of criterion validity, the correlations between instrument scores and PVF symmetry scores were calculated. Additionally, internal consistency of all instruments was calculated and compared to those previously reported. Factor analysis is reported for the first time for LOAD, and is compared to that previously reported for CBPI and HCPI.ResultsSignificant moderate correlations were found between all instruments, implying construct validity for all instruments. Significant weak correlations were found between LOAD scores and PVF symmetry index, and between CBPI scores and PVF symmetry index.Conclusion and Clinical RelevanceLOAD is an owner-completed clinical metrology instrument that can be recommended for the measurement of canine osteoarthritis. It is convenient to use, validated and, as demonstrated here for the first time, has a correlation with force-platform data.

Complications and Owner Assessment of Canine Total Hip Replacement: A Multicenter Internet Based Survey

To assess the variables associated with the complications of total hip replacement (THR) and report owner-assessed outcomes, through surgeon-based registration of cases via an online database, informed owner consent, and prospective outcomes assessment using a client-administered clinical metrology instrument. Prospective case series Dogs (n = 170) Entries into the British Veterinary Orthopaedic Association-Canine Hip Registry (BVOA-CHR) between January 2010 and August 2011 were reviewed. Variables evaluated included dog age, body weight, breed, and indication for THR and prosthesis. Associations between each variable and the incidence of complications were assessed using logistic regression. Additionally, an on-line, owner-administered outcomes assessment questionnaire (modified from the Liverpool Osteoarthritis in Dogs (LOAD) questionnaire) was used to collect data from owners. One hundred and seventy cases met the inclusion criteria. Surgical indications included hip dysplasia and coxofemoral osteoarthritis (n = 150), Legg-Calves-Perthes disease (7), coxofemoral luxation (6), fracture (4), slipped capital physis (2), and femoral head and neck ostectomy revision (1). Surgical implants were from 4 systems. The incidence of surgeon-reported complication was 9.4%. No significant association was identified between weight, age, sex, breed, indication for THR, surgical technique and prosthesis, and the incidence of complications. In 82% of the cases, owners described their satisfaction with the outcome of THR as "very good" and a total of 20% complication rate was reported. There was a statistically significant improvement in owner-assessed questionnaire score before and after THR (P < .001). The BVOA-CHR offers a novel framework for the prospective studies on THR and on a national/international scale. Initial complication rates from the BVOA-CHR are similar to previous studies.

Validation of a client‐based clinical metrology instrument for the evaluation of canine elbow osteoarthritis

To validate a disease-specific client-based clinical metrology instrument (questionnaire) for dogs with chronic osteoarthritis of the elbow joint. This was a prospective cohort study involving 26 dogs with chronic osteoarthritis of the elbow with 24 associated clients. Validity (face and criterion), reliability and responsiveness of the metrology instrument (named "Liverpool Osteoarthritis in Dogs [elbow]") were tested in a sequence of studies. Face validity involved use of international peer review. Reliability was assessed using a test-retest scenario with a two week interval; peak vertical force as measured by a force platform was used as an external standard measure. Responsiveness was tested with a two week, single-blinded placebo-controlled intervention using a licensed non-steroidal anti-inflammatory drug. The reliability of Liverpool Osteoarthritis in Dogs (elbow) in the test-retest scenario was good; intraclass correlation coefficient is 0.89, 95 per cent confidence interval 0.75 to 0.95, compared with intraclass correlation coefficient 0.92, 95 per cent confidence interval 0.74 to 0.98, for peak vertical force. Responsiveness testing indicated that the "net" effect size (allowing for placebo effect) for Liverpool Osteoarthritis in Dogs (elbow) was 0.13 compared with (-)0.18 for the force platform. Criterion validity for Liverpool Osteoarthritis in Dogs (elbow) against peak vertical force was poor; Spearman's rank correlation is -0.24 (P=0.30). Liverpool Osteoarthritis in Dogs (elbow) was considered reliable with satisfactory responsiveness. The poor criterion validity suggests a mismatch between force platform peak vertical force and client perceptions of lameness. This instrument requires further validation in larger studies with alternative client groups and alternative therapeutic interventions, but this initial validation suggests that Liverpool Osteoarthritis in Dogs (elbow) is worthy of continued investigation.