Management of Subchondral Lucencies of the Medial Aspect of the Equine Antebrachiocarpal Joint

The objective of this study is to describe the management and outcomes of eight horses with subchondral lucencies (SCLs) of the medial aspect of the antebrachiocarpal (ABC) joint. The medical records and radiographs of the carpi of 8 horses with SCLs of the medial aspect of the ABC joint were reviewed. Follow-up clinical information was obtained for 6–60 months (the median duration of 14 months). Treatment was successful if radiographic healing was apparent or lameness was reduced or eliminated. Four horses had SCLs in the distomedial radius (DMR) and four in the proximal aspect of the radiocarpal bone (RCB). Lameness was present in all horses with DMR SCLs and in one horse with an RCB SCL. Treatments included restriction of exercise (n = 3), intra-articular administration of corticosteroids (n = 2), or placement of a screw across the SCL (n = 3). Exercise restriction alone was successful in three nonlame horses younger than one year with proximal RCB SCL and intra-articular corticosteroid administration in the ABC joint in two horses aged 2 years or younger with DMR SCLs. A yearling with a large proximal RCB SCL and two horses aged 5 years or older with DMR SCLs were successfully treated with screw placement across the SCL. Exercise restrictions and intra-articular administration of corticosteroids were successful in management of DMR SCLs in five horses. Placing a screw across the SCL of three horses resulted in resolution of lameness and substantial improvement of the radiographic appearance of the lesion in the RCB or DMR.     

Fibromatous epulis in a Campolina horse

An 11-year-old Campolina horse was referred to the Veterinary Hospital due to the presence of an exophytic mass located in the rostral region of the mandible. Radiographic evaluation showed no evidence of tumour infiltration in the underlying mandibular bone, and the histopathology and immunohistochemical evaluations confirmed the diagnosis of fibromatous epulis. The treatment included surgical excision of the mass, followed by extensive curettage of the underlying mandibular bone. Complete healing of the wound was evidenced 60 days after the procedure; however, relapse was reported by the owner between 1 and 3 years after surgery.     

A large cyst in the distal femur of a horse

A 10-year-old Warmblood gelding presented with a left hindlimb lameness. Diagnostic analgesia located the lameness to the stifle. Radiography showed an unusually large cyst in the distal femur. Diagnostic arthroscopy of the stifle did not reveal any significant abnormalities. An extra-articular transcortical approach to the cyst was performed for drainage, curettage, and provision of an autologous, cancellous bone graft, gentamicin-impregnated collagen fleeces and injectable steroid. The horse returned to a higher level of competitive dressage than prior to surgery. This report describes a large cyst in the distal femur of a horse.     

Avulsion of the proximal digital annular ligament in five hindlimbs

Avulsion of the proximal attachment of the proximal digital annular ligament (PDAL) was identified in five horses based on characteristic radiographic findings and supported by ultrasonographic examination in four horses. In two cases, PDAL avulsion was associated with acute onset lameness based on physical examination (both animals) and diagnostic analgesia (one animal), and was the only lesion identified. Both horses became sound after a period of rest. Radiographs repeated 11 years later in one animal showed minimal change in the appearance of the lesion. PDAL avulsion was associated with a substantial tear of the deep digital flexor tendon in another horse and in the remaining two cases PDAL avulsion was not associated with lameness. A dissection study found that the proximodistal extent of the proximal PDAL attachment, expressed as a proportion of the length of the proximal phalanx, was significantly (P = 0.011) greater in hindlimbs (11.48 ± 1.01%) compared with forelimbs (8.55 ± 1.06%). This finding may explain why hindlimbs appear at greater risk of PDAL avulsion. In conclusion, while PDAL avulsion can be a cause of acute lameness which, in uncomplicated cases, responds to rest, it can also be an incidental radiographic finding.     

Short incomplete sagittal fractures of the proximal phalanx in ten horses not used for racing

Objective— To describe short incomplete sagittal fractures of the proximal phalanx (type Ia P1 fractures) in horses not used for racing and report outcome.
Study Design— Retrospective study.
Animals— Horses (n=10) with type Ia P1 fractures.
Methods— Retrieved data of horses with type Ia P1 fractures were signalment, history and results of orthopedic examination. Radiographs were re-evaluated for position and length of the fracture line, presence of osteoarthritis or subchondral cystic lesions (SCL), periosteal new bone formation and subchondral sclerosis. Conservative treatment (n=4) included box confinement for 2 months followed by 1 month of hand walking. Surgical therapy (n=6) consisted of internal fixation by screws inserted in lag fashion in 5 horses. Concurrent SCL were debrided by curettage via a transcortical drilling approach. In 1 horse, only SCL curettage but not internal fixation was performed. Outcome was assessed on a clinical and radiographic follow-up examination in all horses.
Results— Mean follow-up time was 27 months (median, 13.5 months; range, 9 months to 9 years). All horses treated with internal fixation were sound at follow-up and had radiographic fracture healing. Of the 4 horses managed conservatively, 3 remained lame and only 1 horse had radiographic evidence of fracture healing. Catastrophic fracture propagation occurred in 2 horses not treated by internal fixation, 20 and 30 months after diagnosis, respectively.
Conclusions— Horses with a type Ia P1 fracture treated surgically had a better outcome than those managed conservatively and lack of fracture healing seemingly increases the risk of later catastrophic fracture.
Clinical Relevance— Surgical repair of type Ia P1 fractures should be considered to optimize healing and return to athletic use.     

Leukemic small cell lymphoma or chronic lymphocytic leukemia in a horse

A 16‐year‐old, Irish Draft mare was admitted to the referring veterinarian for an annual health check. A mild generalized lymphadenomegaly was noted. Rectal palpation and transrectal ultrasonographic examination revealed prominent mesenteric lymph nodes. A transcutaneous abdominal ultrasonographic evaluation was unremarkable. A CBC revealed a marked leukocytosis (63.06 × 10³/μL) and lymphocytosis (58.2 × 10³/μL) due to increased numbers of small lymphocytes. No evidence of anemia or thrombocytopenia was found and neutrophil counts were low‐normal. Cytologic examination of fine‐needle aspirates of multiple lymph nodes and a bone‐marrow aspirate revealed the presence of a monomorphic population of small lymphocytes similar to those observed in the peripheral blood, suggesting a leukemic small cell lymphoma (SCL) or chronic lymphocytic leukemia (CLL). As the lymphadenomegaly and peripheral blood lymphocytosis were present simultaneously, the distinction between these 2 conditions was not possible. Immunophenotyping by immunocytochemistry and flow cytometry of the lymphoid cells in peripheral blood determined a T‐cell phenotype. As the horse was clinically stable, no treatment was initiated, but regular examinations were undertaken. A CBC repeated 120 days after the diagnosis showed a marked lymphocytosis (157.6 × 10³/μL) with no evidence of anemia or other cytopenias. The horse was euthanized 194 days after the initial diagnosis. Histopathology and immunohistochemistry of submandibular lymph nodes and bone marrow confirmed the diagnosis of leukemic SCL or CLL, and a T‐cell phenotype. SCL and CLL are rare in horses; previous immunohistochemical studies determined that the T‐cell phenotype is predominant. To the authors' knowledge, this is the first report of the combined use of immunocytochemistry and flow cytometry in a horse with leukemic SCL or CLL.     

Locking Compression Plates for Pancarpal Arthrodesis in a Thoroughbred Filly

Objective— To report treatment of a comminuted ulnar carpal (UC) bone fracture associated with carpal instability by pancarpal arthrodesis using 2 locking compression plates (LCP).
Study Design— Case report.
Animals— A 2-year-old Thoroughbred filly.
Methods— An UC fracture and luxation of the proximal row of carpal bones was diagnosed radiographically. Pancarpal arthrodesis was performed with 2 LCP positioned dorsolaterally and dorsomedially and centered over the carpus through a single skin incision. The filly was maintained in a full limb cast for 15 days, followed by a tube cast for 14 days, and subsequently a full limb bandage with caudal splint for 21 days.
Results— Two LCP provided appropriate carpal stability resulting in a pasture sound horse 6 months after surgery. The filly was discharged from the hospital 63 days after surgery, walking well with only a slight mechanical lameness.
Conclusion— Use of 2 LCP applied on the dorsomedial and dorsolateral aspect of the carpus can provide carpal stability for pancarpal arthrodesis.
Clinical Relevance— Excellent stability of the carpal joints can be achieved with 2 LCP.     

Acquired peri-articular ganglion cyst in the lateral femorotibial joint in an 18-year-old Percheron cross mare

This report describes a case of sudden lameness in an 18-year-old Percheron cross mare after presumably being kicked by another horse, and the subsequent formation of a ganglion cyst originating from the lateral femorotibial joint. Physical examination, radiographic and ultrasonographic investigation identified a soft round 5 cm diameter mass attached to the left lateral femorotibial joint. After surgical removal, histopathological examination confirmed a ganglion cyst. The horse responded well to the surgical removal of the cyst, and 4 weeks after the surgery, the mare has returned back to her same athletic performance. According to the authors’ knowledge, this is the first reported case that describes a peri-articular ganglion cyst originating from the stifle joint.     

Treatment of coxofemoral luxation in a mature Welsh pony by femoral head ostectomy: Long‐term outcome

A 233 kg, 4‐year‐old Welsh pony stallion presented with a unilateral coxofemoral luxation and a history of previous upward fixation of the patella. This condition was surgically managed by femoral head ostectomy using a craniodorsal approach to the luxated coxofemoral joint, without greater trochanteric osteotomy. Immediate improvement in weightbearing was observed after surgery and primary intention healing was recorded. Long‐term outcome, 4 years after surgery, was assessed by radiographic, ultrasonographic and lameness examination. The pony was in good body condition and the initial weight of this patient was restored. Despite fetlock hyperlaxity of the contralateral hindlimb, amyotrophy and mechanical lameness of the affected hindlimb, the pony showed evident comfort without apparent signs of pain and was able to trot and gallop. Bone callus was observed at imaging examination.     

Results of single-session bilateral triple pelvic osteotomy with an eight-hole iliac bone plate in dogs: 95 cases (1996-1999)

OBJECTIVE: To evaluate feasibility of single-session bilateral triple pelvic osteotomy with 8-hole iliac bone plates in dogs with bilateral hip dysplasia. DESIGN: Retrospective study. ANIMALS: 95 dogs with bilateral hip dysplasia. PROCEDURE: Medical records were reviewed, and information was obtained on signalment; body weight; angles of subluxation and reduction prior to surgery; durations of surgery and hospitalization; postoperative mobility; severity of lameness, radiographic grade of hip dysplasia, Norberg angle, and femoral head coverage before and after surgery; time required for radiographic evidence of iliac healing; change in pelvic diameter; implant integrity; and complications. RESULTS: Mean age at the time of surgery was 10.8 months, and mean weight was 35.2 kg (77.4 lb). Prior to surgery, mean angles of subluxation were 2.2 degrees on the right and 2.6 degrees on the left; mean angles of reduction were 25.9 degrees on the right and 27.3 degrees on the left. Mean surgical time was 95 minutes. All but 1 dog were able to walk on their own by the fourth day after surgery. Mean hospitalization time was 7.5 days. Clinical signs of lameness and radiographic grade of hip dysplasia were significantly improved during follow-up examinations. Mean time for radiographic iliac healing was 8 weeks. None of the plates and only 7 of the 1,520 (0.5%) screws loosened after surgery. Nineteen dogs had complications, but all complications were minor. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that single-session bilateral triple pelvic osteotomy with 8-hole iliac bone plates is effective for treatment of dogs with bilateral hip dysplasia.     

Evaluation of an arthroscopic approach for transection of the equine collateral sesamoidean ligament

Objective: To evaluate: (1) an arthroscopic technique for transection of the collateral sesamoidean ligament (CSL); and (2) the healing response using magnetic resonance (MR) and microscopic examination. Study Design: Experimental study. Animals: Adult horses (n=6). Methods: Six sound horses with normal front foot radiographic and MR examinations were used. Lameness examination was performed before surgery and monthly for 12 months. Front foot radiography was performed at 180 and 360 days after surgery. Front foot MR was performed before, and at 7, 90, 180, and 360 days after surgery. Arthroscopic CSL desmotomy was performed on 1 forelimb. Gross and microscopic examination was performed on the CSL from both forelimbs at 360 days after surgery. Lameness scores were compared over time using the nonparametric Friedman's test for paired groups. CSL measurements were compared using paired t‐tests with a 2‐tailed significance level of P<.05. Results: Radiographs remained normal throughout study period. Surgery resulted in lameness on the operated limb for up to 2 months, after which all horses returned to soundness. CSL transection was confirmed during arthroscopy and with MR examination 7 days after surgery. Gross and microscopic evaluation confirmed ligament healing. Conclusions: CSL desmotomy resulted in short‐term lameness after surgery followed by healing of the CSL confirmed by gross and microscopic analysis.     

Platelet-rich Plasma Combined With a Sterile 3D Polylactic Acid Scaffold for Postoperative Management of Complete Hoof Wall Resection for Keratoma in Four Horses

Keratoma is a nonmalignant horse tumor that grows in the space between the horn of the hoof and the distal phalanx. Keratoma causes lameness in the horse, and surgical excision is the treatment of choice. Four horses underwent removal of a keratoma by complete hoof wall resection. The remaining wound was treated with platelet-rich plasma (PRP) combined with a sterile three-dimensional polylactic acid scaffold. The PRP was applied at 3, 6, 9, 12, 15, and 18 days postoperatively. The surgical site was cleaned with gauzes and swabs soaked in Ringer’s lactate solution before applying PRP and the foot bandage. Healthy granulation tissue developed at 6–21 days postoperatively. The hoof wall defect was completely filled with new hoof wall within 6–8 months after surgery. All horses returned to their previous exercise level, and no recurrence of lameness was reported by the owner.     

Pathological fracture through a subchondral bone cyst in the proximal phalanx of a horse

A 12‐year‐old Morgan broodmare presented for a nonweightbearing right forelimb lameness. Radiography and computed tomography confirmed the presence of a pathological fracture of the proximal first phalanx through a large subchondral bone cyst (SBC) in the right forelimb and a large SBC in the proximal first phalanx of the left forelimb. Surgical repair of the large palmar medial eminence fracture of the proximal first phalanx fracture was performed using bone screws placed in lag fashion placed through stab incisions after debridement and bone grafting of the SBCs. Approximately 6 months after surgery the mare was ambulating comfortably at pasture. This case report describes a fracture through a large subchondral bone cyst in a horse despite chronicity and ongoing bone remodelling. Careful consideration regarding exercise or use should be considered in horses with large SBCs.     

Placement of bone screws in a standing horse for treatment of a fracture of the greater tubercle of the humerus

A mature Thoroughbred gelding that was used as a high level jumper presented for evaluation of a nonweightbearing forelimb lameness following a fall. Radiographs revealed a complete, noncomminuted, minimally displaced sagittal fracture of the greater tubercle. Supporting limb laminitis was a major concern in the short term based on the severe lameness at presentation. Open reduction with internal fixation was chosen over stall rest in an attempt to more rapidly return the weightbearing function to the limb. The procedure was performed standing and 3 bone screws were placed standing in an attempt to avoid implant or catastrophic bone failure that can accompany recovery from general anaesthesia. The day following surgery the lameness was significantly improved as the horse was able to bear some weight on the heel. The gelding was discharged 5 days following surgery and was fully weightbearing at the walk. Six months following surgery the horse was free of lameness and resumed training. This report describes our experience and rationale in placing bone screws in a standing horse for treatment of a greater tubercle fracture.     

Vascular hamartoma as the cause of hind limb lameness in a horse

We report a 5-year-old gelding with a rare benign tumour of 2-month duration in the subcutis of the hind limb that presented with lameness. Physical examination revealed normal vital signs. Laboratory findings were within normal ranges. No bone abnormalities were detected on radiographic examination of the affected area. Bloody fluid was obtained by aspiration. Through an I-shape skin incision the tumour was excised en-block. Microscopic study showed a vascular hamartoma characterized by cavernous haemangiomatous tissue and proliferation of multiple vessels of variable diameter. This report highlights the importance of limb vascular hamartoma, as an infrequent lesion, in the differential diagnosis of lameness in the horse.     

Collateral ligament reconstruction in two horses following traumatic avulsion fracture using a knotless suture anchor construct

This case report describes a technique for repair of medial collateral ligament avulsions in two horses. Both horses sustained traumatic injuries resulting in avulsion fractures at the origin of their medial tarsal and carpal collateral ligaments. This report describes the use of a knotless suture anchor to mechanically reconstruct medial collateral ligament avulsion injuries in two horses. The first horse, a 9‐year‐old Hannovarian Warmblood gelding presented for an acute nonweightbearing lameness in the right hindlimb. The injury was localised to the medial malleolus of the tibia and an avulsion fracture of the origin of the short medial collateral ligament of the tibiotarsal joint with disruption of the ligament was found on radiographs and ultrasound. The horse was taken to surgery and a reconstruction of the short medial collateral ligament was performed with a modified single row construct using a biocompatible, multistrand, long chain ultra‐high molecular weight polyethylene braided composite suture tape (2 mm Fibertape) and a single knotless suture anchor (5.5 × 19.1 mm PEEK SwivelLock C). The second horse, a 5‐year‐old Thoroughbred gelding presented for an acute nonweightbearing lameness in the left forelimb. The injury was localised to the medial styloid process of the radius and an avulsion fracture of the origin of the medial collateral ligament of the antebrachial carpal joint was found on radiographs and ultrasound. The horse was taken to surgery and a similar reconstruction procedure was performed to the collateral ligament. Both horses were recovered in a Robert Jones bandage without the use of casts or splints and recovered without incident. Both horses are sound and returned to previous level of athletic performance at 18 months and 8 months, respectively.     

Successful Management of Severe Open Metacarpophalangeal Joint Dorsal Luxation in a Horse

A 3-year-old Darreh-Shuri stallion was presented with left forelimb open dorsal fetlock luxation immediately after being hit by a motorized vehicle. The horse was in a non–weight-bearing position on the affected limb. General physical examination revealed normal vital parameters and no special concurrent abnormality. Radiographic examination in lateromedial and dorsopalmar views of the affected limb showed complete luxation of the metacarpophalangeal joint with no fractures. Ultrasonographic evaluation revealed intact collateral ligaments. Under general anesthesia and following routine preparations, forceful manual pressure was exerted on the distal part of the metacarpus and proximal part of the first phalanx to reduce the luxation. Joint capsule and skin laceration were sutured. Intraarticular amikacin (500 mg) was administered and repeated on the third and fifth days postoperatively. A palmar polyvinyl chloride, synthetic plastic polymer (PVC) splint was placed following adequate padding from the carpus to the toe. The higher and lower third of the splint was casted and the middle part left open to manage the joint and skin lesion. Intraarticular sodium hyaluronate (20 mg) was administered 10 days later. After cast removal following 5 weeks, the stallion revealed no sign of lameness. The owner was instructed to keep the stallion confined to a stall for at least 2 more months with a restricted daily short hand walk. Special casting methods for immobilization of a limb with an open joint luxation can tremendously improve the healing process.     

Standing repair of a proximal,incomplete, articular fracture of the third metatarsal bone

A 5-year-old National Hunt Thoroughbred mare presented with sudden onset left hindlimb lameness after race training on the gallops. Clinical examination revealed a marked painful reaction over the proximal metatarsal region but no other obvious abnormalities were detected. Survey radiographs at the yard did not reveal any abnormalities. Nuclear scintigraphic examination 3 days after injury revealed focal marked increased radiopharmaceutical uptake in the proximal metatarsal region. Subsequent radiography revealed an incomplete, articular fracture of the proximal left third metatarsal bone. Repair of the fracture using 3 × 4.5 mm cortical screws placed in lag fashion was performed under standing sedation following perineural analgesia. Follow-up radiographs demonstrated progressive healing of the fracture. The mare returned to race training 8 months after the fracture was repaired and raced successfully 12 months post injury.     

Complete Excision of a Fractured Fourth Metatarsal Bone in Eight Horses

Proximal open comminuted fractures of the fourth metatarsal bone (Mt IV) in eight horses were treated by complete removal of the affected bone and antimicrobial therapy. Two horses had concurrent septic arthritis of the tarsocrural or distal tarsal articulations, and five horses had radiographic evidence of osteomyelitis and sequestration of the affected bone. Five horses became athletically sound for their intended use, two horses with septic arthritis had residual lameness but were pasture sound, and one horse was lost to follow-up. Excision of the entire bone appears to be an acceptable treatment of open comminuted fractures of the proximal one-third of Mt IV that do not respond to more conservative modes of therapy.