Osteolytic lesions of the tuber calcanei in two horses

Regional antibiotic perfusion through the lateral saphenous vein in two horses with septic calcaneal osteitis

In this case report, two horses with chronic refractory infections in the tuber calcanei were successfully managed via intravenous antibiotic regional limb perfusion through the lateral saphenous vein after failure of conventional treatment approaches, including surgery and intravenous regional limb perfusion using the cranial branch of the medial saphenous vein. Surgical delay in these cases may have allowed the development of chronic infection, which prevented the conventional regional perfusion from working effectively. The spatial difference of the vessels relative to the tuber calcanei possibly contributed to the treatment outcome in these horses. This report describes a novel approach for regional antimicrobial perfusion to the equine plantar hock region using the lateral saphenous vein.

A multi-centre cohort study investigating the outcome of synovial contamination or sepsis of the calcaneal bursae in horses treated by endoscopic lavage and debridement

Background

Previous studies investigating factors associated with survival following endoscopic treatment of contamination/sepsis of the calcaneal bursa are limited.

Objectives

To investigate the factors associated with survival in horses with contamination/sepsis of the calcaneal bursae treated endoscopically and to describe the bacterial isolates involved in the synovial infections.

Study design

Retrospective analysis of clinical records.

Methods

Medical records from 128 horses with contamination/sepsis of the calcaneal bursae treated by endoscopic lavage at seven equine hospitals were reviewed. A follow‐up questionnaire was used to determine survival and return to athletic performance. Descriptive statistics and Cox proportional hazards survival models were used to determine factors associated with survival.

Results

Horses underwent one (n = 107), two (n = 19), or three (n = 2) surgeries. Survival to hospital discharge was 84.4%. Univariable survival analysis revealed that administration of systemic antimicrobials prior to referral was associated with reduced mortality (hazard ratio, [HR] 0.41, 95% CI 0.18–0.91, P = 0.03). Increased mortality was associated with bone fracture/osteomyelitis (HR 2.43, 95% CI 1.12–5.26, P = 0.03), tendon involvement (≥30% cross sectional area) (HR 3.78 95% CI 1.78–8.04, P = 0.001), duration of general anaesthesia (HR 1.01, 95% CI 1.00–1.02, P = 0.04), post‐operative synoviocentesis (HR 3.18, 95% CI 1.36–7.43, P = 0.006) and post‐operative wound dehiscence (HR 2.5, 95% CI 1.08–5.65, P = 0.04). Multivariable Cox proportional hazards model revealed reduced mortality after systemic antimicrobial administration prior to referral (HR 0.25, 95% CI 0.11–0.60, P = 0.002) and increased mortality with tendinous involvement (≥30% cross‐sectional area) (HR 7.92, 95% CI 3.31–19.92, P<0.001). At follow‐up (median 30 months, range 0.25–13 years, n = 70) 87.1% horses were alive, 7.1% had been euthanised due to the calcaneal injury and 5.7% had been euthanised for unrelated reasons. From 57 horses with athletic performance follow‐up, 91.2% returned to the same/higher level of exercise, 5.3% to a lower level and 3.5% were retired due to persistent lameness of the affected limb.

Main limitations

Retrospective study and incomplete follow‐up.

Conclusion

Endoscopic treatment of contamination/sepsis of the calcaneal bursae has an 84% survival rate to hospital discharge. Tendinous involvement reduced survival whilst systemic antimicrobials administration prior to referral improved survival.

The cranial nuchal bursa: anatomy, ultrasonography, magnetic resonance imaging and endoscopic approach

REASONS FOR PERFORMING STUDY

Although an uncommon condition, cranial nuchal bursitis can affect the performance of the equine athlete. The anatomy is not well described and there are no reports of diagnostic imaging for endoscopic approaches.

OBJECTIVES

To describe the anatomy, ultrasonographic and magnetic resonance features of and endoscopic approach to the cranial nuchal bursa in horses.

STUDY DESIGN

Experimental cadaver study.

METHODS

Four cranial nuchal bursae were dissected, 4 specimens were frozen to prepare anatomical sections and 2 were injected with latex to document surface landmarks and topographical anatomy and to identify the possible sites for endoscopic access. Six cadaveric specimens were used to describe the ultrasonographic and magnetic resonance features of the cranial nuchal bursa before and after intrabursal injection. Sixteen cadaver specimens were evaluated with a rigid arthroscope and gross dissection to determine the endoscopic appearance of the bursa.

RESULTS

The cranial nuchal bursa could be identified consistently in all cadavers, using ultrasonographic and magnetic resonance on both pre- and post injection specimens. Cranial and caudal endoscopic approaches and instrument portals were developed for the cranial nuchal bursa. Using either approach, the entire extent of the bursa could be evaluated, but separate approaches for left and right compartments of the bursa were needed owing to the lack of manoeuvrability when examining the contralateral compartment.

CONCLUSIONS

The cranial nuchal bursa can be identified on ultrasonographic and magnetic resonance images. An endoscopic approach to the cranial nuchal bursa is clinically feasible and offered an easy, repeatable entry into the cranial nuchal bursa, which allowed adequate observation of the structures within the bursa. This may be of help for diagnosis and treatment of conditions affecting the cranial nuchal bursa in horses.

Injuries of the calcaneal insertions of the superficial digital flexor tendon in 19 horses

REASONS FOR PERFORMING STUDY

Injuries of the calcaneal insertions of the superficial digital flexor tendon and their relationship to displacement of the tendon from the calcaneus have not previously been reported.

OBJECTIVES

To describe findings made on clinical cases with disruption of the calcaneal insertions of the superficial digital flexor tendon (SDFT) including observations on their role in horses with unstable subluxation of the tendon. To describe novel surgical techniques and the results of treatment.

HYPOTHESES

Disruption of the calcaneal insertions of the SDFT is associated with lameness and distension of the calcaneal bursa. Unstable displacement of the SDFT from the calcaneus is a more complex injury than incomplete disruption of one of its calcaneal insertions.

METHODS

The case records and diagnostic images of horses with lesions involving the calcaneal insertions of the SDFT, which were confirmed by endoscopic evaluation of calcaneal bursa between 2005 and 2009, were reviewed.

RESULTS

Nineteen horses were identified including 7 that had unstable displacement of the tendon from the calcaneus. Following endoscopic surgery, 9 of 12 horses with stable tendons and 6 of 7 horses with unstable displaced SDFTs returned to work.

CONCLUSION

Tearing of the calcaneal insertions of the SDFT is associated with lameness and distension of the calcaneal bursa; endoscopic removal of the torn tissue carries a good prognosis. Horses with unstable displacement of the tendon have also disruption of the tendon fibrocartilage cap. Removal of this results in stable subluxation and can return horses to athletic activity. Both lesions can be detected by preoperative ultrasonography.

POTENTIAL RELEVANCE

Tearing of the calcaneal insertions of the SDFT should be included in the differential diagnoses of lame horses with distended calcaneal bursae. Tearing of the tendon fibrocartilage cap in horses with unstable displacement of the SDFT is a plausible explanation of the clinical features of the injury and explains previously unreliable results of reconstructive surgeries. Subtotal resection is a technically demanding technique but appears to offer an improved prognosis.

An anatomic study of the calcaneal bursae in the horse

OBJECTIVES

To establish an injection site for the gastrocnemius calcaneal bursa (GCB), to identify communication patterns between the calcaneal bursae, to estimate the proximal and distal extents of the intertendinous calcaneal bursa (ICB) and to identify variations from previous anatomic descriptions.

STUDY DESIGN

Descriptive anatomic study.

ANIMALS

Cadaveric equine hindlimbs (n=18) from 9 adult horses.

METHODS

Communication between the ICB and GCB was determined in 18 cadaveric hindlimbs by injection of a latex mixture, followed by examination of sequential sagittal sections and documentation of the distribution of the latex mixture and communication sites. The distal and proximal extents of the ICB and subcutaneous calcaneal bursa (SCB), relative to the tuber calcanei (TC) were recorded.

RESULTS

Communication between the ICB and the GCB was confirmed on the medial and lateral aspect in 100% and 50% of limbs, respectively. Communication between the SCB and the ICB, and therefore the GCB, was identified in 39% of limbs. Plantar reflections of the ICB existed in 33% of limbs. Mean extent of the ICB relative to the TC was 7.0 cm distally and 9.6 cm proximally. The SCB often occupies a more distal position than previously reported.

CONCLUSIONS

The ICB and the GCB should be considered 1 synovial structure with 2 communicating compartments.

CLINICAL RELEVANCE

The GCB may be an alternative site for synoviocentesis when there is septic calcaneal bursitis. Improved knowledge of calcaneal bursae anatomy may aid in diagnosis and treatment of lesions involving these structures.

Osseous lesion of the calcaneus following the use of shock wave therapy in a horse

An 8-year-old Dutch warmblood gelding was presented with a mechanical lameness (2/10) because of the presence of a soft tissue injury on the top of the right tuber calcanei. Plain radiographs of the tarsus demonstrated the presence of soft tissue swelling caudal to the right tuber calcanei, without osseous involvement, and ultrasonography revealed excessive scar tissue within and around the superficial digital flexor tendon. Extra-corporeal shock wave therapy was applied on the right hock to decrease the amount of scar tissue. One month after the therapy the lameness was greater (3/10) and a marginal increase in the size of the swelling was found. Periosteal new bone formation associated with an ill-defined radiolucent area and two bony fragments were detected radiographically at the caudo-proximal aspect of the right tuber calcanei. A blister containing oil of croton, camphor, pine and thyme, turpentine and cantharides was applied on the right calcaneus. Twenty days after blister application, the size of the swelling had been reduced by 50% and the degree of lameness had also been decreased (1/10). On clinical re-evaluation 6 months after treatment, the degree of lameness was stable (1/10) and flexion test of the limb was negative.