Treatment of chronic digital septic tenosynovitis in 12 horses by modified open annular ligament desmotomy and passive open drainage

Clinical use of antimicrobial regional limb perfusion in horses: 174 cases (1999-2009)

OBJECTIVE

To describe the clinical use of regional limb perfusion with antimicrobials (A-RLP), complications, and outcome in a large series of patients.

DESIGN

Retrospective case series.

ANIMALS

174 horses.

PROCEDURES

Medical records of horses treated with A-RLP between 1999 and 2009 were reviewed. Signalment, primary complaint, horse use, etiology, duration of clinical signs, previous treatment, structures involved, concurrent conditions, A-RLP characteristics, additional treatments, complications, and outcome were recorded. At long-term follow-up, 2 outcomes were investigated: survival rate and return to previous use at the same or higher level. Univariate and multivariate logistic regression analyses were conducted.

RESULTS

Group 1 (96 horses) included septic synovitis. Group 2 (50 horses) included extrasynovial lacerations (23 horses) and fresh, minimally contaminated intrasynovial lacerations without evidence of established synovial infection (27 horses). Group 3 (28 horses) included miscellaneous other conditions. Only minor complications were reported in 12.26% of horses that received IV (n = 155) and 33% of horses that received intraosseous (27) A-RLP. Horses with septic synovitis had a lower survival rate (53.43%) than did horses with lacerations (91.89%). Within group 2, no significant differences in short- or long-term outcomes were found between horses with extrasynovial and fresh, minimally contaminated intrasynovial lacerations. For the horses returning to previous use, 80% of horses with septic synovitis and 72.72% of horses with lacerations were performing at the same or higher level at the time of follow-up.

CONCLUSIONS AND CLINICAL RELEVANCE

The results of the present study indicated that A-RLP is a safe technique with minimal adverse effects. The IV route presented fewer complications than intraosseous injection. Horses with infection of synovial structures had a lower survival rate than did those with acute, minimally contaminated intrasynovial lacerations. The latter had a similar prognosis for horses with extrasynovial lacerations treated with A-RLP.

Tenosynoviotomy for sepsis of the digital flexor tendon sheath in 9 horses

OBJECTIVE

To describe a tenosynoviotomy technique for treatment of sepsis of the digital flexor tendon sheath (DFTS) in horses and report long-term outcome.

STUDY DESIGN

Case series.

ANIMALS

Horses (n = 9).

METHODS

Horses were positioned in lateral recumbency with the affected limb uppermost. A linear incision was made just lateral to the mesotenon beginning 5 cm proximal to the apices of the proximal sesamoid bones, extending 2 cm distal to the bifurcation of the superficial digital flexor tendon (SDFT). The incision was continued through the skin, subcutaneous tissue, palmar/plantar annular ligament, and DFTS. Tenotomy of the distal lateral branch of the SDFT was also performed. The site was thoroughly debrided, lavaged, and packed with gauze and allowed to heal by second intention. Follow-up was obtained via owner telephone interview.

RESULTS

Mean surgery time was 32 minutes (range, 10-64 minutes). Systemic antibiotics were administered postoperatively (range, 11-46 days; mean, 23 days). Mean hospitalization was 11 days (range, 0-49 days). Follow-up was available for 7 (70%) horses. One year postoperatively, 5 (71%) horses were serviceable for their intended use, and 2 (29%) had been euthanatized. Of 5 survivors, 3 returned to ridden exercise, 1 was retired as a broodmare, and 1 was a broodmare. All owners were satisfied with the cosmetic appearance of the surgery site.

CONCLUSION

Open drainage via tenosynoviotomy, performed as a salvage procedure, represents a feasible treatment for DFTS sepsis.

Use of a radiofrequency probe for tenoscopic-guided annular ligament desmotomy

REASONS FOR PERFORMING STUDY

Annular ligament desmotomy is commonly performed in horses with chronic tenosynovitis. Previously reported tenoscopic techniques have limitations related to haemorrhage and awkward instrumentation. Radiofrequency (RF) energy affords precision and excellent haemostasis and may be a good alternative to sharp transection of the annular ligament in horses.

OBJECTIVE

To describe a technique for using a RF probe for tenoscopic-guided annular ligament desmotomy and to report the clinical outcome of horses in which it was performed.

METHODS

Cadaver specimens (n = 14) and live horses undergoing unrelated terminal procedures (n = 2) were used to optimise the tenoscopic-guided RF annular ligament desmotomy technique. Records were examined for all horses undergoing annular ligament desmotomy with an RF probe from 2003 to 2008 for which follow-up of >1 year post operatively was available.

RESULTS

The annular ligament was successfully transected in the cadaver and live horse model limbs using 2 different commercially available RF probes. Complete transection was achieved with practice and confirmed on gross dissection. Histopathology did not reveal any collateral damage to surrounding tissue. Follow-up of >1 year was available for 6 of 7 clinical cases. Four of 6 horses returned to work. Owners were satisfied with the outcome in all cases.

CONCLUSIONS

Desmotomy using a RF probe allows precise tissue transection under tenoscopic guidance without damage to surrounding structures or haemorrhage. With experience, it is an easily performed technique. In clinical patients, an acceptable outcome may be expected.

POTENTIAL RELEVANCE

Tenoscopic-guided RF annular ligament desmotomy offers advantages, including reliable haemostasis and precise tissue transection, over previously reported techniques and is a viable surgical alternative for treating horses with annular ligament desmitis and other complex pathology within the tendon sheath.

What is the likelihood that a horse treated for septic digital tenosynovitis will return to its previous level of athletic function?

REASONS FOR PERFORMING STUDY

Septic digital tenosynovitis is a serious problem in the horse, with a poor prognosis being reported for recovery.

HYPOTHESIS

The occurrence of septic digital tenosynovitis would significantly reduce the likelihood of a horse returning to its previous level of athletic function.

METHODS

Medical records of 90 horses treated for septic digital tenosynovitis were reviewed. Data retrieved included age, sex, location of inciting cause of sepsis, time from onset of clinical signs to presentation for treatment, and whether the horse survived to be discharged. Long-term outcome was determined through telephone questionnaires. Univariate analyses of categorical variables were conducted for each outcome.

RESULTS

Overall, 87.8% of horses (79/90) survived to be discharged from the hospital. Only one factor examined was shown to have a significant effect on outcome. A delay of 1-7 days between onset of clinical signs and presentation for treatment reduced significantly the likelihood of the horse surviving to be discharged from the hospital. Of the horses discharged from the hospital, long-term follow-up was available for 72 horses, with 54.2% (39/72) returning to their previous level of athletic function.

CONCLUSIONS

Only approximately 50% of horses treated for septic digital tenosynovitis returned to their previous level of athletic function following resolution of synovial sepsis.

POTENTIAL RELEVANCE

Accurate figures allowing a realistic assessment of the athletic future of a horse following treatment for septic digital tenosynovitis are of value to both the owner and treating veterinarian.

Tenoscopic surgery for treatment of lacerations of the digital flexor tendon sheath

REASONS FOR PERFORMING STUDY

Lacerations to the digital flexor tendon sheath (DFTS) are a common injury in the horse, but little information is available in the literature regarding prognostic indicators.

OBJECTIVE

To ascertain whether laceration of the DFTS carried a better prognosis if treated by tenoscopic lavage, debridement and repair within 36 h of the original injury.

METHODS

A retrospective analysis of 39 horses treated surgically for lacerations to the DFTS was performed over a 3 year period. The injury-to-surgery interval was recorded as <36 or >36 h. The structures damaged by the injury were also recorded, as well as age, sex, use and outcome.

RESULTS

Sixteen horses had laceration and contamination of the DFTS alone, of which 15 (94%) returned to their original or intended use. Sixteen horses had lacerations involving the superficial digital flexor tendon, of which 12 (75%) made a full recovery. Six horses had lacerations to both superficial and deep digital flexor tendons, 5 were subjected to euthanasia intraoperatively and one is paddock sound. Treatment within 36 h of initial laceration carried a significantly better prognosis for return to intended athletic use (25 of 28 horses allowed to recover from anaesthesia) than treatment after 36 h (2 of 5 P = 0.03; Fisher's Exact Test).

CONCLUSIONS

If sepsis is treated early using tenoscopic visualisation, lavage and repositol antibiotics, the limiting factor in return to athletic function is tendon damage.

POTENTIAL RELEVANCE

This study supports anecdotal evidence that early treatment of synovial sepsis improves the prognosis for return to intended use. It also provides information on prognostic indicators including extent of damage to collateral structures.

Factors associated with outcome following treatment of horses with septic tenosynovitis: 51 cases (1986-2003)

OBJECTIVE

To identify factors associated with outcome (ie, survival and return to function) following treatment of horses with septic tenosynovitis.

DESIGN

Retrospective case series.

ANIMALS

51 horses with septic tenosynovitis.

PROCEDURES

Information was obtained from medical records and through follow-up conversations with owners. Factors analyzed for an association with outcome included affected limb, etiology, duration of clinical signs prior to examination, presence of complications, primary treatment, secondary treatments, number of surgical procedures, and hospitalization time.

RESULTS

Concurrent complications were identified in 41 (80%) horses. The primary treatment consisted of through-and-through lavage in 26 (51%) horses, tenoscopy in 20 (39%), and tenosynoviotomy combined with lavage in 5 (10%). Forty (78%) horses were discharged, and 37 (73%) survived at least 1 year after surgery; 21 of the 37 (57%) returned to their previous or a higher level of performance. Percentages of horses that survived 1 year after discharge and percentages that returned to their intended use did not vary significantly among treatments. Horses with tendon rupture or sepsis of an adjacent joint were significantly less likely to survive. Horses with tendon injury or pannus were significantly less likely to return to their intended use.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that various factors were associated with outcome in horses with septic tenosynovitis. However, surgical technique was not found to be associated with survival rate or rate of return to intended use.

Evaluation of a balloon constant rate infusion system for treatment of septic arthritis, septic tenosynovitis, and contaminated synovial wounds: 23 cases (2002–2005)

OBJECTIVE-To determine clinical findings and outcome in horses treated by means of a balloon constant rate infusion system. DESIGN-Retrospective case series. ANIMALS-23 horses. PROCEDURES-Medical records of horses examined at The Ohio State University veterinary teaching hospital from 2002 to 2005 that had septic arthritis, septic tenosynovitis, or penetration of a synovial structure and in which treatment involved a balloon constant rate infusion system were searched. Information pertaining to signalment, history, physical examination findings, clinicopathologic data, treatment, and duration of hospitalization was recorded. RESULTS-Mean+/- SD duration of hospitalization was 11.5+/-5.26 days. No correlation between duration of clinical signs and duration of hospitalization or duration of infusion pump use was detected, but correlations between WBC count and duration of hospitalization and WBC and duration of infusion-pump use were observed. All horses survived to discharge. Follow-up information was obtained on 17 horses, 16 of which were alive at the time of follow-up. Twelve of 13 horses for which followup information was available for at least 5 months were alive 5 months or longer after discharge. Thirteen of the 16 horses alive at follow-up were reported by owners as not lame, whereas the remaining 3 were mildly lame or intermittently moderately lame or had developed angular limb deformity in the contralateral limb. CONCLUSIONS AND CLINICAL RELEVANCE-Balloon constant rate infusion systems may be used effectively in treatment of septic arthritis, septic tenosynovitis, and contaminated synovial wounds. Clinical response and long-term outcome appeared to be comparable to results obtained with other techniques.

Wounds of the distal limb complicated by involvement of deep structures

The authors describe the clinically relevant structures of the distal limb and the current diagnostic and treatment modalities. Specific problems include tendon laceration, septic tenosynovitis, and sep-tic arthritis of the distal joints. A detailed description of tendon repair, tendon sheath lavage, and postoperative convalescent methodology is provided. This article makes available to the reader information necessary to appropriately diagnose and treat wounds of the distal equine limb involving deep structures. Information on the overall prognosis is also provided.

Use of antimicrobials in wound management

Antimicrobial medication should be considered an adjunct to the general care of wounds rather than a substitute for lavage, drainage, or other physical care intended to promote healing. Judicious use is based on results of diagnostic procedures and the professional judgment of the attending veterinarian. Organisms that contaminate or infect wounds of horses are similar to those that can affect human patients, such that personal hygiene and protection are important when caring for these equine patients, because attendants can easily be exposed to them. Although those organisms are considered to be ubiquitous, the inoculum that may be present on or in an infected wound may be substantially greater than that encountered during other daily activities of the veterinarian. Proper disposal of the bandage materials and personal protective clothing is important. Bacterial resistance is one of many "survival tactics" of bacteria and has been an important clinical consideration for physicians and veterinarians since antimicrobial drugs were discovered. Controversies and insufficient understanding of bacterial resistance abound, however. The entirety of the subject is beyond the scope of this article, but it is important to the veterinary profession and for the formulation of wound management in horses. We and our animal patients live in a world populated by microbial organisms of various types. Resistance among bacteria is likely to continue to be a clinical consideration in the future as it has been during the past 60 to 70 years. As veterinarians, we must recognize the zoonotic nature of resistance and implement biosecurity procedures to protect ourselves, other people in contact with those pathogens, and our patients. We must also recognize the merits of judicious targeted use of antimicrobial drugs and apply appropriate principles during the course of professional care for the well-being of our animal patients.