Patella tendinopathy Zoobiquity - What can we learn from dogs?

Anterior cruciate ligament zoobiquity: Can man's best friend tell us we are being too cautious with the implementation of osteotomy to correct posterior tibial slope

Anterior cruciate ligament (ACL) reconstruction (ACLR) is used to treat clinical instability post ACL rupture, however, there is a high rate of incomplete return to sport and rerupture. There is increasing interest in posterior tibial slope as an intrinsic risk factor for ACLR failure and persistent instability. Zoobiquity describes the collaboration between the human and veterinary professions in order to advance the scientific understanding of both fields. Given the cranial cruciate ligament (CCL) in dogs is synonymous with the anterior cruciate ligament in humans, functioning to control internal rotation and anterior translation, but osteotomies, rather than ligament reconstruction, are the mainstay of treatment for CCL rupture, this editorial sort to gain insights into this form of treatment from the veterinary world. Level of Evidence: Level V, evidence.

Lateral fenestration of lumbar intervertebral discs in rabbits: development and characterisation of an in vivo preclinical model with multi-modal endpoint analysis

PURPOSE

To evaluate the biological and biomechanical effects of fenestration/microdiscectomy in an in vivo rabbit model, and in doing so, create a preclinical animal model of IVDD.

METHODS

Lateral lumbar IVD fenestration was performed in vivo as single- (L3/4; n = 12) and multi-level (L2/3, L3/4, L4/5; n = 12) fenestration in skeletally mature 6-month-old New Zealand White rabbits. Radiographic, micro-CT, micro-MRI, non-destructive robotic range of motion, and histological evaluations were performed 6- and 12-weeks postoperatively. Independent t tests, one-way and two-way ANOVA and Kruskal-Wallis tests were used for parametric and nonparametric data, respectively. Statistical significance was set at P < 0.05.

RESULTS

All rabbits recovered uneventfully from surgery and ambulated normally. Radiographs and micro-CT demonstrated marked reactive proliferative osseous changes and endplate sclerosis at fenestrated IVDs. Range of motion at the fenestrated disc space was significantly reduced compared to intact controls at 6- and 12-weeks postoperatively (P < 0.05). Mean disc height index percentage for fenestrated IVDs was significantly lower than adjacent, non-operated IVDs for both single and multi-level groups, at 6 and 12 weeks (P < 0.001). Pfirrmann MRI IVDD and histological grading scores were significantly higher for fenestrated IVDs compared to non-operated adjacent and age-matched control IVDs for single and multi-level groups at 6 and 12 weeks (P < 0.001).

CONCLUSIONS

Fenestration, akin to microdiscectomy, demonstrated significant biological, and biomechanical effects in this in vivo rabbit model and warrants consideration by veterinary and human spine surgeons. This described model may be suitable for preclinical in vivo evaluation of therapeutic strategies for IVDD in veterinary and human patients.

Exploring the One Health Paradigm in Male Breast Cancer

How cancer patterns in humans compare to those of other species remains largely unknown and there is an even bigger knowledge gap for rare cancers like male breast cancer. One Health is a convergence of human and animal healthcare that encourages cross-pollination of medical research uniting human and veterinary medicine. Recognising that breast cancer occurs spontaneously in other male species (e.g. primates, canines, felines), and knowing that no laboratory models exist for male breast cancer, which limits our ability to perform functional studies, we explored the feasibility of applying One Health to breast cancer in men by conducting a narrative review of the topic. Spontaneous development of breast cancer was reported in captive male primates and in companion canines and felines. Some parallels in tumour biology of human male breast cancer with canines and primates were found. The age distribution, pattern of biomarker expression and metastasis were similar, with mammary tumours typically detected after two-thirds of average lifespan. However, instances of triple negative and inflammatory breast cancer, which are rarely observed in human male breast cancer, were found in canines and histological classification was inconsistent between species. These disparities need redressing to enable full exploration of the One Health paradigm in rare cancers.

Patellar tendon angle is not elevated in ACL-injured subjects, suggesting methods to correct should focus on prehabilitation and rehabilitation rather than surgery

Purpose

The aim of the study was to explore if the patellar tendon angles (PTAs) is an intrinsic risk factor for anterior cruciate ligament (ACL) rupture. We hypothesised that the PTAs will be increased in ACL rupture patients compared to matched controls.

Methods

We performed a retrospective radiographic cohort study. A cohort of ACL-injured patients between 2019 and 2022 was utilised. The control population, from the same time period, was a consecutive series of 100 patients without ligament or meniscal injuries which were prospectively added to our institutional registry. Posterior tibial slope (PTS), static anterior tibial translation (SATT), patellar tendon to tibial plateau angle (PT-TPA), patellar tendon-tibial shaft angle (PT-TSA) were measured.

Results

A total of 100 patients were included in the control cohort and 110 in the ACL cohort. The PT-TPA was significantly less in the ACL cohort compared to the control cohort, mean and SD of 15.33 (±5.74) versus 13.91 (±5.68), respectively (p = 0.01). PT-TSA was also less in the ACL cohort, mean and SD of 116.15 (±5.89) versus 114.27 (±4.81), however, this failed to reach statistical significance (p = 0.08). The PT-TPA was not correlated with PTS (p = 0.65) and the PT-TSA was inversely correlated with PTS; Pearson correlation coefficient of -0.28 (p < 0.01). The PT-TSA had a greater correlation -0.4 (p < 0.01) with SATT than PTS 0.37 (p < 0.01).

Conclusion

PTAs are not elevated in ACL-injured subjects. While anteriorisation of the tibial tubercle is utilised in dogs to decrease the anterior thrust resulting from the anteriorly directed vector of the quadriceps, this treatment in the humans is not warranted and methods to reduce the PTAs should focus on prehabilitation and rehabilitation.

Level of Evidence

Level III.

Morphology of the stifle in agouti (Dasyprocta prymnolopha, Wagler 1831)

The agouti (Dasyprocta prymnolopha, Wagler 1831) is a wild rodent of great zootechnical potential, a fact that enables anatomical and morphological studies to support management actions with this animal. In this perspective, this study aimed to describe the anatomy and histology of the agouti stifle joint. Four adult agoutis were used, two females and two males. The animals were submitted to dissection and identification of the structures of the stifle joint. For light microscopy study, samples of the patellar ligament, cranial and caudal cruciate ligaments, medial and lateral collateral ligaments were used. Agouti has a highly congruent patellofemoral joint; elongated patella; medial and lateral fabellae at the proximal insertion of the gastrocnemius muscle; medial and lateral meniscus with lunula; in addition to the presence of the following ligament structures: patellar ligament, cranial and caudal cruciate ligaments, medial and lateral collateral ligaments, meniscofemoral ligament, caudal meniscal ligament of the medial meniscus, and medial and lateral cranial ligaments. The patellar ligament presents bundles of parallel collagen fibers with a straight path and coated fibroblasts; collateral and cruciate ligaments had loose and dense connective tissue, coated fibroblasts and collagen bundle undulations, the latter most expressive in the caudal cruciate ligament. Thus, except for the shape and angulation of the stifle, which allows specific movements, the agouti stifle has structures analogous to that of other rodents and domestic animals.

Distalising tibial tubercle osteotomy decreases patellar tendon force - A treatment rationale for recalcitrant patellar tendinopathy

BACKGROUND

Patellar tendinopathy is an overuse condition affecting athletes, often with a high morbidity if left untreated. High-level evidence fails to support the use of surgery. A tibial tubercle osteotomy (TTO) has been suggested as a surgical option to improve patient outcomes. Our aim was to explore whether a distalising TTO will alter the patellar tendon to quadriceps tendon force ratio and the sagittal patellar tilt.

METHODS

Six cadaver limbs were placed in a custom jig with a mechanical testing machine applying cyclical loads of 200-500 N to the quadriceps tendon. The knee was fixed at 0, 15, 30, 45, 60, 75 and 90° of flexion and a buckle transducer recorded the resultant patellar tendon force. Testing was performed with the native tibial tubercle position and with the tubercle distalised by 11 mm. Testing was also performed with the tubercle anteriorised by 10 mm at both of these tubercle positions, a total of four different testing positions.

RESULTS

There was a significant decrease in the patellar tendon to quadriceps tendon force ratio from 30-60° of knee flexion. There was a significant increase in the sagittal patellar tilt at 30° of knee flexion with distalisation.

CONCLUSION

This biomechanical study shows that the patellar tendon to quadriceps tendon force ratio can be altered with a distalising tibial tubercle osteotomy. A tibial tubercle osteotomy may be a biomechanical treatment option for recalcitrant patellar tendinopathy by decreasing the load through the patellar tendon, allowing the athlete to maintain higher training volumes and loads.