Frederik Volz

Objective: To compare the biomechanical effects of hemilaminectomy (HL) and mini-hemilaminectomy (mHL) on the stability of the feline lumbar spine at L4-L5. Methods: 20 cadaveric feline vertebral columns were collected from June 26, 2021, through September 15, 2022; the biomechanical testing was conducted from November 23, 2023, through March 6, 2024. Lumbar spines were screened radiographically and by CT, tested in the native state, and then randomly assigned to HL or mHL at L4-L5. Nondestructive cyclic bending in lateral bending and flexion/extension was performed with an electrodynamic testing machine. Vertebral motion was quantified with 3-D optoelectronic motion capture. Mixed-effects models compared native and postoperative states and surgical groups. Results: 20 vertebral columns were eligible; 2 were used to establish the testing protocol, 4 were excluded, and 14 completed testing and were analyzed (7/group; HL and mHL). No significant differences in stability were detected between unaltered HL and unaltered mHL groups or between groups after HL versus mHL. Intragroup comparisons (unaltered HL vs HL; unaltered mHL vs mHL) showed significantly greater motion for multiple stability variables after both procedures, with more variables affected after HL than mHL. Conclusions: Both decompressive procedures decreased biomechanical stability of the feline lumbar spine relative to the native condition. Although direct differences were not detected, HL produced a more consistent pattern of increased motion than mHL. Clinical Relevance: Although HL showed a more consistent pattern of increased motion, no significant differences between techniques were detected; therefore, any clinical advantage of mHL remains unproven.

Objective: To evaluate the relationship between goniometric stifle range of motion (gROM), active stifle range of motion (aROM), and stifle osteoarthritis (sOA) in dogs with cranial cruciate ligament disease (CCLD) and to assess the association between gROM and aROM in CCL-affected and control dogs. Methods: Dogs weighing 20 to 40 kg with CCLD before surgery (CCL-Dogs) and orthopedically healthy controls (C-Dogs) were enrolled between August 1, 2020, and August 1, 2021. Objective gait analysis was performed on a treadmill using a 2-D marker-based system. Goniometric stifle extension (gSE) and goniometric stifle flexion (gSF) were measured 3 times by 3 observers. sOA was scored on a scale from 1 (none) to 4 (severe). Spearman rank correlation ( r ) described associations between sOA, gROM, and aROM. Results: 15 CCL-Dogs and 10 C-Dogs were included. These preliminary data demonstrated that in CCL-Dogs, gROM ( r = –0.644) and gSE ( r = –0.751) showed significant correlations with sOA. No significant correlations were found between sOA and active stifle flexion ( r = –0.160), active stifle extension ( r = –0.138), aROM ( r = 0.036), or gSF ( r = 0.198). No significant correlation was observed between aROM and gROM in either CCL-Dogs ( r = –0.346) or C-Dogs ( r = –0.127). Conclusions: In C-Dogs and CCL-Dogs, aROM and gROM are not associated. In CCL-Dogs, sOA is associated with reduced gROM and gSE, indicating that gROM rather than aROM reflects joint impairment. Clinical Relevance: Goniometric measurement of stifle extension may serve as a practical indicator of osteoarthritic severity and functional limitation in dogs with CCLD.

Introduction: Extracorporeal shockwave therapy (ESWT) is used as an adjunctive treatment for canine osteoarthritis (OA), but its effects in dogs with treatment-refractory advanced disease remain unclear. This study compared the efficacy of one versus two sessions of focused ESWT administered approximately 28 days apart in dogs with refractory elbow or stifle OA. Methods: In this randomized, double-blinded clinical trial, twenty-four client-owned dogs with treatment-refractory elbow (n = 12) or stifle (n = 12) osteoarthritis received ESWT using an identical per-session protocol (X-Trode, 1000 pulses at 0.14 mJ/mm²; PulseVet-Zomedica, Ann Arbor, MI, USA), once (Group L) or twice (Group E). Orthopedic examination, goniometric and limb circumference measurements, and kinetic gait analysis (peak vertical pressure [PVP], vertical impulse [VI]) were performed on days 0, 28, and 56. Owner questionnaires (Canine Brief Pain Inventory [CBPI], Client Specific Outcome Measures [CSOM]) were collected on days 0, 28, 56, and 84. Data were analyzed using chi-squared tests, t-tests, and mixed effects models in R. Results: Age, weight, BCS, and radiographic osteoarthritis severity did not differ between groups at baseline. Improvement was small and limited to selected parameters. Vertical impulse and limb circumference increased more consistently in Group E, whereas peak vertical pressure increased in both groups, including before ESWT in Group L. No sustained or treatment-associated improvement was detected in symmetry variables or joint range of motion. Owner-reported outcomes showed variable patterns without consistent treatment effects. ESWT was well tolerated, and no major adverse events occurred. Conclusion: ESWT produced modest, inconsistent improvements in dogs with treatment-refractory OA, with slightly more consistent effects following two sessions. Therapeutic efficacy appeared limited in this end-stage population.

Objectives: The objectives of the study were to investigate the association between change in postoperative (post-op) tibial plateau angle (TPA) in dogs and cranial cruciate ligament disease (CCLD) after tibial plateau leveling osteotomy (TPLO) during 6 months on the post-op outcome.Methods: The inclusion criteria included 60 dogs with CCLD treated with TPLO fulfilled. TPA measurements were taken immediately post-op and 6 months post-op by three observers, and change in TPA was calculated. The outcome was evaluated using lameness score, owner questionnaire, and gait analysis performed preoperatively and 6 months post-op.Results: The mean change in TPA was 0.22 ± 0.75°. The interobserver reliability for TPA measurements was excellent. No differences in TPA measurements between observers were found (p = 0.07–0.105). No association between the change in TPA and outcome was found. The multivariate linear regression model for the symmetry index of peak vertical force (SIPVF) 6 months post-op was significant (R² = 0.210; p = 0.031), and the TPA at 6 months post-op was the only significant factor (ß = 0.459; 95% CI: 0.41–1.44; p < 0.001), indicating that a lower TPA 6 months post-op results in lower SIPVF values.Conclusion: The study indicated that lower TPAs 6 months post-op lead to a more symmetrical gait in hindlimbs 6 months post-op. No other significant factor between post-op changes in TPA and outcome after TPLO was found. Our results showed little post-op TPA change up to 6 months. This indicates that change in TPA is not present as reported.

Background: Goniometry can be performed clinically in dogs with cranial cruciate ligament disease (CCLD). The purpose of this study was (1) to compare reliability of stifle goniometry in dogs with CCLD and healthy dogs and (2) to investigate the effect of compliance on measurements. Dogs presented for surgical intervention for CCLD (CCL-Dogs; n = 15) and orthopedically healthy dogs (C-Dogs; n = 11) were enrolled in this prospective randomized controlled trial. In each dog, three observers randomly measured maximum stifle flexion (mSF) and maximum stifle extension (mSE) three times with a standard goniometer with the scale covered, while dog compliance was scored (Scores: C0: excellent - C4: poor). Intraclass correlation coefficient (ICC) was calculated for intra-/interobserver reliability. Effects on measurements were evaluated with mixed-effect models (MEM). Results: Maximum stifle extension and mSE-compliance were significantly decreased in CCL-Dogs compared to C-Dogs (p ≤ 0.004), but mSF and mSF-compliance did not differ between groups. Intraobserver reliability was excellent for all dogs during mSE (ICC:0.75–0.99) and mSF (ICC:0.89–0.99). Interobserver reliability was excellent for mSF in both groups (ICC: C-Dogs:0.84, CCL-Dogs:0.9) and for mSE in CCL-Dogs (ICC:0.94) but only fair for mSE in C-Dogs (ICC:0.58). Robust MEM showed that the combined average of all mSE measurements of all three observers was affected by compliance in both groups (p < 0.001). This effect was not observed for single mSE-measurements by themselves. Conclusion: The results of this study indicate that compliance may affect goniometric stifle extension measurements in healthy and CCLD dogs. In a clinical setting, intra-/interobserver reliability was excellent for all measurements except for maximum stifle extension in healthy dogs.

Objectives: This study aimed to investigate the recovery of limb function following a single intra‐articular injection of platelet‐rich plasma or hyaluronic acid in dogs with cranial cruciate ligament rupture treated with tibial plateau levelling osteotomy compared to dogs receiving no injection intraoperatively.Materials and Methods: Sixty‐two dogs with cranial cruciate ligament rupture, body weights of 20 to 40 kg, and no other orthopaedic conditions were enrolled in this prospective, randomised, double‐blind, controlled study at the small animal clinic at LMU Munich. All dogs underwent tibial plateau levelling osteotomy. Based on random allocation, they received either a single intra‐articular injection of platelet‐rich plasma, hyaluronic acid or no injection intraoperatively. Gait analysis, clinical examinations, radiography of the stifle joint for osteoarthritis progression and two validated owner questionnaires were compared among groups at three timepoints postoperatively (6 weeks, 3 and 6 months). Limb function was primarily assessed by measuring the ground reaction forces.Results: At all times postoperatively, no differences were observed among groups regarding clinical examinations, osteoarthritis score values, ground reaction forces or owner questionnaires. All dogs showed significant improvement in limb function clinically, in all ground reaction forces and in the validated questionnaires. Osteoarthritis progressed minimally during rechecks in all dogs regardless of the additional injection or not.Clinical Significance: All dogs treated with tibial plateau levelling osteotomy for cranial cruciate ligament rupture showed improvements in limb function. No additive effect on faster recovery was demonstrated with the additional intra‐articular injection of platelet‐rich plasma or hyaluronic acid. Addition of platelet‐rich plasma/hyaluronic acid injections during tibial plateau levelling osteotomy is unnecessary considering the lack of benefit observed up to 6 months postoperatively.