Preactivation of the quadriceps muscle could limit cranial tibial translation in a cranial cruciate ligament deficient canine stifle

Proximal femoral fixation method and axial load affect simulated muscle forces in an ex vivo feline limb press

OBJECTIVE

To quantify how increasing axial loads combined with different femoral fixation methods impact simulated quadriceps and gastrocnemius muscle forces.

STUDY DESIGN

Experimental, non-randomized, ex vivo study.

METHODS

A custom limb press permitting axial loads of 10%-40% bodyweight with three femoral fixation models was tested with 24 limbs from 12 cats (4 per method). Fixation models were: one-complete hip mobility, two-rigid femoral fixation, three-flexion-extension hip mobility. Femoral angulation to horizontal of 60° ±5° and stifle/hock angulations of 120° ±5° were maintained using turnbuckles. Primary outcomes were bodyweight normalized quadriceps and gastrocnemius forces, and their ratio. Secondary outcomes were radiographic limb angulation and relative foot position for models 2 and 3.

RESULTS

Normalized quadriceps forces increased more with axial load in models 1 and 3 than model 2 (p = .04), whereas normalized gastrocnemius force increased more with model 2 than models 1 and 3 (p = .009). Force ratios were unaffected by axial load (p = .4), but model 2 ratios were lower than models 1 and 3 (p = .007). Femoral angulation did not differ with load (p = .1) or model (p = .9), but both stifle and hock flexed with increasing load (p < .001) but remained largely within target. Relative foot position was mean 3.9 mm more caudal in model 2 than model 3.

CONCLUSION

Simulated muscle forces were proportionate to axial load, while rigid femoral fixation negatively affected both forces and ratios.

CLINICAL SIGNIFICANCE

Retaining hip flexion-extension yields normalized quadriceps forces closer to in vivo values and could improve current ex vivo models.

Ex vivo biomechanical investigations of combined extra- and intracapsular stabilization in canines with cranial cruciate ligament deficiency

Intracapsular reconstruction (ICR) has long been recommended as a treatment for cranial cruciate ligament deficiency (CCLD) in dogs, but it has fallen out of favor due to its inferior long-term functional outcomes. These outcomes may be attributed to the poor stiffness and strength of the graft in the early period before ligamentization is completed. Additional placement of extracapsular sutures to mechanically protect the graft during the ligamentization process may be a viable method to address this problem. However, the biomechanical effect of this combined surgical approach remains unknown. This study aimed to evaluate the 3D kinematics of the CCLD stifle in dogs in response to ICR and combined extra- and intracapsular reconstruction (CEICR). Twelve hindlimbs were collected from nine cadavers of mature dogs. The limbs were tested using a custom-made testing apparatus that reproduces their sagittal plane kinematics during the stance phase. Four statuses of stifle joints were tested, namely, (a) cranial cruciate ligament (CCL) intact; (b) CCLD; (c) CCLD stifle stabilized by CEICR; and (d) CCLD stifle stabilized by ICR only. Three-dimensional stifle kinematics at the 5 instances of the stance phase were measured with an optoelectronic system. The results showed that ICR marginally corrects the increased adduction, internal rotation, and caudodistal stifle joint center displacement that occur as a result of CCLD. CEICR led to better restoration of the stifle kinematics, especially with respect to the internal rotation and cranial translation stabilities. Furthermore, CEICR only resulted in minor excessive restraints on other motion components. The findings indicated that the additional lateral fabellotibial suture offers immediate stability to the stifle, consequently lowering the risk of graft over-elongation in the short term postoperatively. Considering the propensity for the extracapsular suture to degrade over time, further in vivo studies are warranted to explore the long-term effects of the CEICR procedure.

Muscle function assessment of the hindlimbs in healthy dogs using acoustic myography

INTRODUCTION

Impaired muscle function is a frequent consequence of musculoskeletal disorders in dogs. Musculoskeletal disorders, especially stifle joint diseases, are common in dogs and assessment of muscle function in dogs is clinically relevant. Acoustic myography (AMG) is a non-invasive method to assess muscle activity. Quantifying muscle function in normal dogs could help identify clinically relevant changes in dogs with orthopaedic disease and allow targeted interventions to improve recovery in these. The objectives of the study were to characterize hindlimb muscle function in healthy dogs using AMG and to investigate the repeatability and reproducibility of AMG in dogs.

METHODS

Healthy dogs (15-40 kg) without musculoskeletal disorders were recruited and screened for eligibility to participate in the study. The muscle activity in four hindlimb muscles related to the stifle was assessed using AMG. The degree of symmetry between the hindlimbs in these dogs was investigated and the reliability of AMG was evaluated.

RESULTS AND CONCLUSIONS

The study population comprised 21 dogs. Reference intervals and symmetry indices for AMG scores of the hindlimb muscles were identified, with highest variability for the E-scores. For all AMG-scores, same-day variation was lower than between days variation, and both were lowest for S- and T-scores. Further investigation is needed to establish if AMG can enable discrimination between dogs with altered muscle function and healthy dogs.

Patellar luxation and concomitant cranial cruciate ligament rupture in dogs - A review

A patellar luxation and concomitant cranial cruciate ligament rupture is a common pathology in dogs. Diagnosis is based on clinical evidence of a patellar luxation and stifle joint instability. However, diagnostic imaging is required to assess the number of skeletal deformities and signs of instability. Surgical options include both soft tissue and osseous techniques, although, in most cases, a combination of multiple procedures is necessary to correct the patellar luxation and restore the stifle joint stability. Complication rates are generally low, but can include reluxation and implant-associated complications. This article describes the patellar luxation and cranial cruciate ligament rupture signs in dogs, including the clinical presentation and diagnosis, and discusses current treatment options.

Effect of tibial plateau levelling osteotomy and rehabilitation on muscle function in cruciate-deficient dogs evaluated with acoustic myography

The objective of the study was to determine the function of the biceps femoris, quadriceps, gastrocnemius and semitendinosus muscles at the walk in dogs with unilateral clinical cruciate disease and palpable joint instability. To compare function before and after a tibial plateau levelling osteotomy (TPLO) procedure, and after six weeks of subsequent rehabilitation therapy. Fourteen adult client-owned dogs with cranial cruciate ligament deficiency (CCLD). Orthopaedic examination, temporospatial gait analysis and acoustic myography (AMG) recordings were made at three time points: before TPLO, and post-operatively at two and eight weeks. A rehabilitation program started 2 weeks after surgery and was either in-clinic along with in-home rehabilitation or in-home only. Statistics included: repeated measures ANOVA and paired t-tests. Significance was set at P<0.05. When comparing the affected versus the unaffected limb in the CCLD dogs, there were no significant differences found in AMG values between baseline and other time points for the quadriceps and semitendinosus muscles. The gastrocnemius and biceps femoris muscles had a significant change in spatial summation (S) score over time. The gastrocnemius (S) score was not significantly different to the unaffected limb by 8 weeks post TPLO. There was no significant effect of rehabilitation method on S score. Dogs with in-clinic rehabilitation regained more symmetry in thigh circumference versus in-home only. Lameness parameters improved but did not completely resolve in all dogs by week 8 post TPLO. The function of the gastrocnemius muscles in affected limbs was significantly different to normal limbs at baseline and 2 weeks post TPLO but not at 8 weeks. Thigh symmetry, but no other parameters, was improved with the addition of in-clinic rehabilitation.

The effect of motor learning and fatigue on preactivation of the lower extremity muscles during different jumps

BACKGROUND

The first step in identifying risk factors for injuries is to characterize the myoelectric activity of different muscles after ground contact, especially when fatigue is a limiting factor. This study aimed at recording the myoelectric activity of calf muscles after ground contact during different types of jumps and investigating the effect of motor learning and fatigue on muscle preactivation.

METHODS

Twenty four male students aged 24.3±1.2 years old performed three different motor activities: A) jump from a box with counter landing (JCL) on 30x30 cm plate; B) drop jump with bounce drop jump (BDJ); and C) BDJ followed by a jump on 51-cm step. The surface electromyography was used to examine the following muscles: m. tibialis anterior (TA), m. gastrocnemius medialis, m. gastrocnemius lateralis, and m. soleus (SO). The measurements were taken during different jumps before and after motor learning and fatigue stimulus.

RESULTS

There were significant differences in preactivation for TA between JCL and BDJ followed by a jump under the influence of fatigue (P<0.05). The differences were observed also during BDJ between non-fatigued and fatigued conditions. There was a statistically significant difference for GL between BDJ pre- and postmovement motor learning and BDJ pre- and postfatigue influence.

CONCLUSIONS

Current results indicate that myoelectric activity of muscles during motor activities is different, and the effect of motor learning and fatigue was shown. Thus, it could be important in the injury prevention in sport.