Gracilis muscle injury as a cause of lameness in two horses

Case Report: Unable to Jump Like a Kangaroo Due to Myositis Ossificans Circumscripta

A male 10-year-old captive red kangaroo (Macropus rufus) was presented with a chronic progressive pelvic limb lameness and reluctance to jump. The general examination revealed a palpable induration of the lumbar epaxial muscles. Magnetic resonance imaging performed under general anesthesia revealed bilateral almost symmetric, well-circumscribed mass lesions in superficial erector spinae muscles. The lesions had irregular to multilobulated appearance with hyper-, hypo-, and isointense areas in T2- and T1-weighted (w) sequences without contrast enhancement. On computed tomography, a peripheral rim of mineralization was apparent. Histopathological analysis of a muscle biopsy showed osseous trabeculae with rare clusters of chondrocytes indicating metaplasia of muscle tissue to bone. No indications of inflammation or malignancy were visible. The clinical, histopathological, and imaging workup of this case was consistent with myositis ossificans circumscripta. This disorder is particularly well-known among human professional athletes such as basketball players, where excessive, chronic-repetitive force or blunt trauma causes microtrauma to the musculature. Metaplasia of muscle tissue due to abnormal regeneration processes causes heterotopic ossification. The kangaroo's clinical signs improved with cyto-reductive surgery, cage rest, weight reduction, and meloxicam without further relapse.

Minimally invasive tenotomy of the tibial insertion of the semitendinosus muscle: An ex vivo study in horses

OBJECTIVE

To describe a minimally invasive technique for semitendinosus tenotomy with ultrasonographic guidance and to evaluate procedural complications.

STUDY DESIGN

Experimental study.

SAMPLE POPULATION

Cadaveric equine hind limbs (n = 16).

METHODS

A stab incision was performed distocaudal to the tibial insertion of the semitendinosus muscle with ultrasonographic assistance. After transection of the tendon with an arthroscopic retrograde knife, the tendon edges palpably retracted, and complete transection was confirmed by ultrasound. Limbs were dissected to confirm the degree of tendon transection and to identify iatrogenic trauma to surrounding soft tissues.

RESULTS

Tenotomy was complete in all limbs, resulting in a palpable gap forming between tendon edges. Superficial iatrogenic laceration to the underlying gracilis muscle (n = 2) or gracilis fascia (n = 1) was apparent in 3 of 16 limbs.

CONCLUSION

Ultrasound-assisted tenotomy of the tibial insertion of the semitendinosus muscle was reliably performed in a minimally invasive fashion with minor iatrogenic damage.

CLINICAL SIGNIFICANCE

Minimally invasive tenotomy of the semitendinosus muscle can be performed with ultrasonographic assistance and should be considered as an alternative technique for surgical management of fibrotic semitendinosus myopathy.

Standing myotomy to treat fibrotic myopathy: 22 cases (2004-2016)

OBJECTIVE

To report the clinical and diagnostic findings associated with fibrotic myopathy, describe the surgical procedure for standing fibrotic myotomy and report postoperative outcomes.

STUDY DESIGN

Retrospective study.

SAMPLE POPULATION

Twenty-two horses.

METHODS

Records were included if a clinical diagnosis of fibrotic myopathy was based on clinical and/or ultrasonographic examination and the horse was treated with myotomy of the affected muscle. Records were reviewed for signalment, preoperative findings, perioperative complications, and outcomes. Follow-up also included a phone survey of owners.

RESULTS

Quarter horses represented 14 of 22 horses in this study. Ultrasonographic examination was performed in 14 of 22 horses. The semitendinosus muscle was affected in 17 of 22 horses. Other muscles affected included the semimembranosus, gracilis, and biceps femoris. Four of the 22 horses had a diagnosis of incisional postoperative complications. Eight of 12 formerly athletic horses returned to their intended athletic use. Ten of 16 owners were satisfied with the procedure.

CONCLUSION

Prognosis for long-term comfort after standing fibrotic myotomy was fair with appropriate rehabilitation. Ultrasonographic examination was helpful in identifying the muscles affected and aided in surgical planning.

CLINICAL IMPACT

Standing fibrotic myotomy is a technically straightforward procedure that yields a fair outcome in horses with minimal intraoperative and/or postoperative complications.

Myositis ossificans circumscripta of the triceps muscle in a Rottweiler dog

A 20-month-old male Rottweiler dog was presented with the complaint of chronic right forelimb lameness that was unresponsive to conservative treatment. Physical examination allowed for the topographical identification of the source of the problem as a firm enlargement of the soft tissues that was partially movable from humeral bone and compatible with an alteration of the triceps brachii muscle. Radiographic images showed signs that were highly suggestive of myositis ossificans. Computed tomography allowed for a more accurate characterization of the lesion, to exclude involvement of the elbow joint and humeral bone, and to localize anatomically the lesion in the caput accessorium and longum of the triceps brachii muscle. Surgical excision of the ossified portion of the triceps muscle was performed. Histological examination of the excised tissue substantiated the diagnosis of myositis ossificans. A one year clinical and radiographic follow-up examination showed a complete recovery, with no evidence of complications or recurrence. Despite myositis ossificans in dogs having previously been identified in the hindlimbs, this case of myositis ossificans circumscripta of the triceps muscle suggests that it may also occur in the muscles of the forelimb.

Autobionics: a new paradigm in regenerative medicine and surgery

The concept of bionics was developed 50 years ago and represented the development of engineering and technology based on natural biological systems. Traditional applications of bionics in healthcare include artificial bionic organs that apply engineering principles to replace or augment physiological functions by integrating electronic, mechanical or electromechanical components to inherent body tissues/organs (we term this as 'exobionics'). Recently, there has been a new wave of bio-inspired treatments that act through the reorganization of the existing biological organs in an individual to enhance physiology. Here, the technology does not replace biological tissue, but rather applies engineering principles to replace or augment physiological functions by the rearrangement and manipulation of inherent tissue/organs; we term this autobionics. Examples include: dynamic cardiomyoplasty (artificial heart pump using skeletal muscle), the Ross procedure (pulmonary autograft), dynamic graciloplasty (artificial sphincter) and metabolic gastric bypass (rearranging the gastrointestinal tract to modify gut- and pancreatic-hormone release). Autobionic therapies can be classified into dynamic, static and metabolic procedures. This results in tissue redesignation (one tissue used in place of another), tissue replacement and systems reorganization (rearranging inherent organ/tissue anatomy). In some cases autobionic procedures can enhance physiological function beyond normality and represents a new era in bio-inspired versatility.