Arthroscopic Removal of Axial Osteochondral Fragments of the Proximoplantar Aspect of the Proximal Phalanx Using Electrocautery Probes in 23 Standardbred Racehorses

Athletic prognosis following arthroscopic removal of osteochondral fragments of the proximal dorsal sagittal ridge of the fetlock in Thoroughbreds intended for flat racing

OBJECTIVE

To establish racing prognosis in Thoroughbred yearlings with proximal sagittal ridge osteochondral lesions and compare them to dorsoproximal and palmar/plantar first phalanx osteochondral lesions.

ANIMALS

A total of 47 horses had proximal sagittal ridge lesions, 34 had palmar/plantar first phalanx lesions, and 115 had dorsoproximal first phalanx lesions.

STUDY DESIGN

Retrospective case series.

METHODS

Medical records of Thoroughbred yearling racing prospects treated arthroscopically for fetlock osteochondral lesions were reviewed. Data were collected from a public database, including the ability to train and race, earnings, starts, wins, and placed races. Racing prognosis was analyzed and compared between three lesion locations.

RESULTS

Of the proximal sagittal ridge group, 76.6% raced, 65.71% of the palmar/plantar first phalanx group, and 74.58% of the dorsoproximal first phalanx group. Career length was similar for all lesions. A lower number of "starts" in the group "five years old and older" was found for the dorsoproximal first phalanx group compared to the cohort with proximal sagittal ridge lesions. Mares had more "earnings" at two years old but fewer "starts" at "five years old" compared to colts and geldings. Forelimb lesions were predictive for fewer total career starts.

CONCLUSION

Proximal sagittal ridge lesions had similar prognoses to dorsoproximal and palmar/plantar first phalanx lesions. In older horses, there was an increase in the number of starts for the proximal sagittal ridge group compared to the dorsoproximal first phalanx group. Mares and forelimb lesions were associated with decreased racing starts.

CLINICAL SIGNIFICANCE

These findings aid in prognostication for Thoroughbreds with osteochondral lesions removed arthroscopically in the fetlock joint.

Vascularity evaluation of the equine tarsocrural and proximal intertarsal joint septum, and comparative analysis of two arthroscopic transection techniques

OBJECTIVE

To evaluate vascularity of the synovial membrane covered septum (SMS) separating the tarsocrural (TC) and proximal intertarsal (PIT) joints (Part 1) and compare two methods of transection, electrosurgical or Ferris Smith rongeur (FS rongeur) (Part 2).

STUDY DESIGN

Experimental study.

SAMPLE POPULATION

Part 1, 10 SMS (n = 5 horses). Part 2, six horses (n = 12 tarsi).

METHODS

In part 1, SMS harvested postmortem were each divided into eight regions of interest (ROIs), processed for histology, and immunostained with anti-α-actin antibody for blood vessel identification. Vascular density was calculated for each ROI. Data was compared within and between horses. In part 2, six horses underwent TC arthroscopy. Each limb was randomly assigned to undergo either electrosurgical or FS rongeur SMS transection. SMS transection and total operative time were recorded. Intraoperative hemorrhage was scored. Data was compared between both techniques.

RESULTS

Significant interindividual variations in SMS vascular density were detected (p = .02), but there were no differences among ROIs. No differences in the transection time were detected between electrosurgery (4.83 ± 0.54 min) and FS rongeur (4.33 ± 0.67 min). No differences were found in intraoperative hemorrhage scores between techniques.

CONCLUSION

Vascularity within the SMS varies among horses but not within its regions. Electrosurgical or FS rongeur transection of the medial SMS during tarsocrural arthroscopy is a rapid technique and improves surgical access to the dorsal compartment of the PIT.

Arthroscopic removal of osteochondral fragments in the dorsal pouch of the proximal intertarsal joint in 29 horses

OBJECTIVE

To describe the radiographic and surgical findings of horses with osteochondral fragments (OCF) in the proximal intertarsal joint (PIJ) and to detail the technique for arthroscopic fragment retrieval and report outcomes.

STUDY DESIGN

Retrospective case series.

ANIMALS

Twenty-nine horses (32 tarsi) with OCF in the PIJ.

METHODS

Medical records of horses with radiographic evidence of OCF in the PIJ were reviewed. Clinical features, number of fragments, location, arthroscopic appearance, and outcome were recorded. Technical modifications with visual aids specific to this arthroscopic technique are described.

RESULTS

Twenty-seven horses (93%) had radiographic evidence of osteochondritis dissecans lesions in the tarsocrural joint (TCJ). OCF were most commonly located distal to the medial trochlear ridge of the talus. In all cases, fragments were successfully retrieved with a technique based on exposing the fragments after resection of the proximal intertarsal joint capsule (PIJC). Fragments were visible from the TCJ prior resection of the PIJC in 4 of 32 tarsi. A third portal was created to access fragments located distal to the lateral trochlear ridge in 3 of 32 tarsi. Moderate intra-articular bleeding occurred when the PIJC was resected in 3 of 32 tarsi. One horse had postoperative swelling that resolved with conservative medical management. All horses with long-term follow-up available (16/29) started training or returned to their athletic career.

CONCLUSION AND CLINICAL SIGNIFICANCE

The arthroscopic technique based on resection of PIJC was effective in retrieving OCF in the PIJ and was associated with minor complications. The clinical relevance of these fragments in the PIJ remains unknown.

Racing performance in Standardbred trotting horses with proximal palmar/plantar first phalangeal fragments relative to the timing of surgery

REASONS FOR PERFORMING STUDY

Proximal palmar/plantar osteochondral fragmentation of the first phalanx is a frequent radiographic finding in Standardbred horses. These lesions are routinely removed prior to the onset of a racing career with no evidence to support the timing of this surgical intervention.

OBJECTIVES

To determine whether horses racing before surgery slowed as they approached surgery date and whether they speeded up after surgery. To investigate the factors affecting whether a horse raced after surgery and compare the performance of horses that did and did not race before surgery.

STUDY DESIGN

A retrospective study using 193 Swedish Standardbred trotters.

METHODS

Medical records and radiographs of each horse were examined. Racing data were retrieved from official online records. Generalising estimating equations were used to examine presurgery racing performance and determine whether this differed between horses that raced before surgery and those that had not. Multivariable regression was used to examine career earnings and number of career races.

RESULTS

Horses racing before surgery neither slowed as they approached surgery, nor speeded up after surgery. Race speed of horses raced before surgery was not different from those that only raced after surgery. Racing before surgery was not associated with whether horses raced following surgery. Only horses with 3 affected legs had slower race speeds than other horses. No other horse level variables affected race speed, number of career races, career earnings or top speed.

CONCLUSIONS

There was no significant difference in race speed between horses that raced before surgery and those that did not. Horses did not slow down prior to surgery. Horses with 3 affected legs ran slower than those with only a single or 2 affected limbs. There was no association between timing of surgery and race speed or career longevity. The potential benefits of surgical intervention should be critically examined.