Single transphyseal screws for the correction of moderate to severe angular limb deformities in 28 Thoroughbred foals

This study reports on the effective use of a single transphyseal screw for the treatment of moderate to severe angular limb deformities (ALDs) of the fetlocks and carpi of 28 young Thoroughbred foals. The objective was to evaluate the surgical management of foals with moderate to severe ALDs treated with single transphyseal screws. Evaluation of medical records of 28 Thoroughbred foals treated with single transphyseal screws placed across the distal radial, metacarpal and metatarsal physes was undertaken. The angle of joint deviation was measured prior to implantation and at removal of the implants, and the degree of improvement was calculated. A total of 39 screws were placed: 24 in the distal metacarpus or metatarsus and 15 in the distal radial physis. Varus or valgus deformities in the fetlock improved by 4–5° over a period of 15–30 days. Varus or valgus deformities in the carpi improved by 8–11° in 11–56 days. One case failed to improve adequately due to implant infection. Single transphyseal screws were effective in treating moderate to severe varus and valgus ALD of the fetlocks and carpi in young Thoroughbred foals. Further investigation into their use in the distal radius in young foals is needed. While single transphyseal screws are almost exclusively used by some clinics in the distal metatarsal and metacarpal physes, many clinicians do not use them in the distal radial physis of young foals due to fear of over‐correction, physitis and metaphyseal collapse. This was not observed in any of our cases.     

The use of an absorbable bone screw as a transphyseal bridge for the correction of fetlock varus deviations in six foals

This report describes and evaluates the use of a single‐positional absorbable screw (Smart Screw) ¹ as a temporary transphyseal bridge of the lateral aspect of the distal metacarpus in 6 foals with fetlock varus deformities. Using radiographic and visual assessments, an improvement in the severity of the deviation was identified in all cases. There were no complications encountered during screw placement or post operatively. The use of absorbable screws in the treatment of angular limb deformities in foals has potential and offers several advantages over the use of traditional stainless steel implants.     

Complications after two transphyseal bridging techniques for treatment of angular limb deformities of the distal radius in 568 Thoroughbred yearlings

Reasons for performing study: Surgical correction of carpal angular limb deformities by growth retardation is commonly undertaken with a screws and tension band wire loop technique (S&W) or a single transphyseal screw (STS). This study compares complications after S&W and STS bridging in the distal radius of Thoroughbred yearlings. Objective: To compare the prevalence of complications serious enough to require follow‐up radiographs following either S&W or STS surgery for growth manipulation in the distal radius of Thoroughbred yearlings. Methods: Medical records and radiographs from Thoroughbred yearlings (age range 261–457 days) treated for carpal angular limb deformities at a single hospital over 2 years were reviewed. Each of the techniques was used exclusively during a single year. The complication threshold criterion for inclusion was the need for nonroutine radiographs of the operated site anytime after implant insertion or removal. Results: Of 568 horses, 253 received S&W and 315 received STS. Horses were of similar age at the time of surgery for STS and S&W. Single transphyseal screws were left in place for a significantly shorter amount of time (16 days). Sex, the limb(s) treated and medial vs. lateral placement were not significantly different between techniques. Complications included physitis post implant removal, metaphyseal collapse post implant removal, infection, overcorrection and seroma formation severe enough to require radiography. Physitis and metaphyseal collapse occurred significantly more frequently with STS compared with S&W. Infection, overcorrection and seromas were not significantly different between techniques. Conclusion: The STS and S&W techniques are both viable treatment options for correction of carpal angular limb deformities. However, horses treated with the STS technique have a significantly increased risk of developing physitis or metaphyseal collapse. Potential relevance: Horses treated with STS bridging have a significantly increased risk of developing the post correction complications of moderate to severe physitis and metaphyseal collapse compared with horses treated with S&W bridging.     

Realignment of the radius in canine antebrachial growth deformities treated with corrective osteotomy and bilateral (type II) external fixation

OBJECTIVE: To identify factors affecting radial alignment after oblique corrective osteotomy stabilized with a type II external fixator and to evaluate the results of this treatment for antebrachial growth deformities. STUDY DESIGN: Retrospective study SAMPLE POPULATION: Twenty-eight dogs with unilateral antebrachial growth deformities treated with acute corrective osteotomy stabilized with a type II external fixator. METHODS: Medical records and preoperative and postoperative radiographs of the affected and contralateral limb were reviewed. Cause of deformity, age, weight, and gender were recorded. Radial length, varus/valgus angulation, and cranial/caudal angulation were measured from radiographs of the treated and contralateral limbs. Preoperative and postoperative angulation and length discrepancy were compared between affected and contralateral limbs. RESULTS: Correction of varus/valgus angle discrepancy was achieved by using acute corrective osteotomy stabilized with type II external skeletal fixation. No significant change was noted for correction of cranial/caudal angle discrepancy or length discrepancy between the affected and control limb. CLINICAL RELEVANCE: Varus/valgus angle deformities can be treated successfully with type III external fixation after oblique corrective osteotomy. Patients with significant length or cranial/caudal angle discrepancies or both that negatively impact function may require the use of hinged circular fixators or other dynamic techniques to achieve adequate correction.     

Developmental aspects of distal limb conformation in the horse: the potential consequences of uneven feet in foals

REASONS FOR PERFORMING STUDY: Distal limb conformation is generally accepted to be an important item with respect to performance and soundness in mature horses, but little is known about the developmental aspects. OBJECTIVES: To gain insight into the development of distal limb conformation and to assess the possible consequences of uneven feet in foals. METHODS: Conformation of the distal front limbs of 23 Warmblood foals was scored visually and measured using radiographs, at ages 27 and 55 weeks. At the same ages, pressure measurements were made under both front feet. RESULTS: At both ages the hoof-pastern axis was broken-backwards on radiographs, but only occasionally recognised as such, when scored by eye. Over time, the hoof angle decreased, while both the angles of the dorsal and solar surfaces of the distal phalanx (P3) increased and the parallelism between hoof wall and P3 improved. The foals with uneven feet at age 27 weeks showed a significant difference in distal limb loading that persisted until age 55 weeks. CONCLUSIONS: The alignment of the distal limb in the sagittal plane increased in a 6 month period. Visual assessment was not sensitive enough to appreciate this. The growth processes in the distal limb could not compensate for existing unevenness and ensuing asymmetrical limb loading. POTENTIAL RELEVANCE: Foals have a different conformation of the distal limb from mature horses, which should be taken into account when interpreting radiographs. Unevenness of the feet resulted in asymmetrical loading of the proximal and distal interphalangeal joint, which might lead to increased susceptibility to overload injuries and decreased performance at mature age.     

Farriery for the foal: A review part 2: Therapeutic farriery

The extensive nature of this topic warrants this review paper to be divided into two parts: ‘Basic trimming in foals’ and ‘Therapeutic farriery in foals’. Management of the feet and limbs during this juvenile period will often dictate the success of the foal as a sales yearling or mature sound athlete. Overall hoof care in the foal is often a joint venture between the veterinarian and the farrier. The orthopaedic disorders discussed in this paper that require input from the two professions are flexural limb deformities (FLD) and angular limb deformities (ALD). The concept of protecting the foot from the deleterious effects of mal-loading created by many FLDs and ALDs is just as important as using the symptomatology as an instrument to correct the deformity. This paper presents a review of the current information regarding the farriery for these two limb deformities while dispelling some of the anecdotal methodology, such as the use of toe extensions to treat flexural deformities, that presently exists. Considering the deficiency of information in the literature, segments of this text will be based on the author's extensive clinical practice, comprehensive clinical records and comparisons of case outcomes.     

A single screw technique compared to a two screw and wire technique as a temporary transphyseal bridge for correction of fetlock varus deformities

A single screw technique is described as a temporary transphyseal bridge for the treatment of fetlock varus angular limb deformity in foals. This has been compared to tension band wiring with regards to rate of correction, cosmetic result and incidence of complications. The single screw was found to be an effective technique resulting in more rapid improvement of deviations in foals aged up to 5 months. Complications were minimal following both techniques and the final cosmetic result was better following single screw surgery.     

Carpal valgus in llamas and alpacas: Retrospective evaluation of patient characteristics,radiographic features and outcomes following surgical treatment

This study evaluated outcomes of surgical treatment for carpal valgus in New World camelids and correlated successful outcome (absence of carpal valgus determined by a veterinarian) with patient characteristics and radiographic features. Univariable and multivariable analyses of retrospective case data in 19 camelids (33 limbs) treated for carpal valgus between 1987 and 2010 revealed that procedures incorporating a distal radial transphyseal bridge were more likely (P = 0.03) to result in success after a single surgical procedure. A greater degree of angulation (> 19°, P = 0.02) and younger age at surgery (< 4 months, P = 0.03) were associated with unsuccessful outcome. Overall, 74% of limbs straightened, 15% overcorrected, and 11% had persistent valgus following surgical intervention. To straighten, 22% of limbs required multiple procedures, not including implant removal. According to owners, valgus returned following implant removal in 4 limbs that had straightened after surgery.     

Musculoskeletal disorders in neonatal foals

Angular limb deformities are not uncommon in foals. Mild angular deviation due to laxity of supporting soft tissues often resolves spontaneously. However, external splinting or casting may be needed in severe cases or in those that do not resolve. When incomplete ossification of carpal or tarsal bones is the cause of the limb deformity, external support is mandatory to prevent further deformation and abnormal development of the bones. When epiphyseal and metaphyseal abnormalities cause axial deviation, surgical intervention is usually necessary. Circumferential periosteal transection and/or transphyseal bridging are methods used. The choice is dictated by the type and severity of the deformity. Flexor contractures of the forelimb vary greatly in degree and joints affected. Physical therapy combined with intermittent splint application is often successful, but surgical intervention may be necessary in unresponsive cases. Flexor tendon laxity is usually self-correcting but physical therapy, restricted exercise, and splinting may be needed. Rotational abnormalities are easier to correct in the forelimbs than in the hind limbs. Correction is usually accomplished by frequent corrective hoof trimming. Miscellaneous anomalies of the musculoskeletal system may sometimes be amenable to surgical correction, although the potential disadvantages must be carefully considered. Septic arthritis is a frequent sequela to neonatal septicemia and must be treated aggressively and early in its development. Appropriate systemic antibiotics, joint lavage, and rest are indicated. Neonatal osteomyelitis has a poor prognosis and requires prompt, vigorous therapy; even then, growth anomalies of the limb or contiguous septic arthritis may develop and further worsen the prognosis. Early accurate diagnosis and prompt appropriate therapy are vital in treating musculoskeletal disorders in foals, especially when a successful outcome is judged by the animal becoming a functional athlete.     

A lag-screw technique for bridging of the medial aspect of the distal tibial physis in horses

A lag-screw technique for transphyseal bridging of the medial aspect of the distal tibial physis in foals with tarsal valgus deformities and results of the technique in 11 foals (6 with bilateral tarsal valgus deformities and 5 with unilateral tarsal valgus deformities) are described. Briefly, horses were anesthetized, and a single stab incision was made through the skin to the underlying bone over the most distal aspect of the medial malleolus. A 20-gauge needle was placed in the incision to guide screw placement, and a lag screw was inserted parallel to the medial cortex of the tibia under radiographic guidance. Screws were removed when the tarsal valgus deformity was clinically assessed to have improved by at least 80%. Clinically, all horses had evidence of a tarsal valgus deformity of > 7 degrees prior to surgery. Mean age at the time of lag-screw implanation was 220 days (range, 116 to 364 days). Mean time the implant was in place was 62 days (range, 39 to 89 days). The tarsal valgus deformity resolved in all 11 horses with excellent cosmetic results.     

Septic osteitis of the distal phalanx in foals: 22 cases (1995-2002)

OBJECTIVE: To determine the clinical characteristics and outcome of foals with septic osteitis of the distal phalanx. DESIGN: Retrospective case series. ANIMALS: 22 foals. PROCEDURES: Information obtained from medical records included signalment; clinical, laboratory, and radiographic findings; treatment method; and outcome. Foals included in the study had lameness referable to the foot, radiographic evidence of localized lysis or focal loss of bone density of the distal phalanx, and suppurative discharge or necrosis of the affected bone evident at surgery. Foals with a history or evidence of penetrating wounds or subsolar abscessation were excluded. RESULTS: Mean age of foals at initial evaluation was 40.8 days (range, 3 to 122 days). Twenty-one (95%) foals had lameness as the primary complaint. Lesions consistent with septic osteitis of the distal phalanx localized to specific areas of the bone on the basis of radiographic and surgical findings were located on the solar margin or toe (14/22 [64%]), extensor process (5/22 [23%]), and palmar or plantar process (3/22 [13%]). Hind limbs (18/26 [69%] affected limbs) were more frequently affected. Two foals had > 1 affected limb, 2 had additional sites of osteomyelitis, and 4 had concurrent septic arthritis. Surgical debridement and regional antimicrobial perfusion were performed during general anesthesia. Extensor process lesions were not debrided. Nineteen of 22 (86%) foals survived to be discharged from hospital, and 16 horses reached racing age. Eleven of 16 had race starts, of which 8 had official race starts and 3 had unofficial race starts. CONCLUSIONS AND CLINICAL RELEVANCE: Septic osteitis of the distal phalanx should be considered as a source of lameness in foals with signs referable to the foot and does not necessarily preclude a career in racing. Although infection may occur secondary to bacterial penetration of the hoof or sole, the distal phalanx should also be considered as a potential site for hematogenous septic arthritis or osteomyelitis in foals.     

Foot management in the foal and weanling.

Foot management and hoof care of foals, weanlings, and yearlings tends to be considered a specialist job. Many farriers and veterinary surgeons have little exposure to young and growing stock. Nevertheless, a variety of angular and flexural limb deformities can benefit from simple podiatry techniques, which can be performed provided that a few basic rules are followed. The combined skills of the farrier and veterinary surgeon offer many young horses with angular or flexural limb deformities a chance of a future athletic career.     

Racing and sales performance after unilateral or bilateral single transphyseal screw insertion for varus angular limb deformities of the carpus in 53 thoroughbreds

Objective: To evaluate the racing and sales performance of Thoroughbred horses with varus angular limb deformities of the carpus treated by unilateral or bilateral single transphyseal screw (STS) placement. Study Design: Case series. Animals: Thoroughbred horses (n=53). Methods: Medical records (January 1, 2005–December 31, 2006) of yearling Thoroughbreds treated for carpal angular limb deformity by transphyseal screw insertion in the distal aspect of the radius were reviewed. Retrieved data were sex, surgery, and screw removal dates, surgical site, appearance, limb(s) affected, type of angular limb deformity, and degree of angular deviation measured by a goniometer. Racing and sales data were collected for analysis from an online racing site for all treated horses and their maternal siblings. Results: No significant differences were identified between treated horses and their maternal siblings in yearling sale price, 2‐year‐olds in training sale price, percent starters, percent winners, and starts, earnings, and earnings/start made during the 2‐ and 3‐year old years. Conclusions: No deleterious effects on sales or racing performance were identified after use of STS in the distal aspect of the radius of Thoroughbreds for the treatment of varus angular limb deformities of the carpus.     

Standing placement of transphyseal screw in the distal radius in 8 Thoroughbred yearlings

This retrospective study describes placement of distal radial transphyseal screws in Thoroughbred yearlings with carpal varus deformities while standing, and identifes short- and long-term complications following the procedure. Data gathered from 2009 to 2013 identified 8 yearlings that met the inclusion criteria. Horses were sedated intravenously and a single 4.5-mm cortical screw was placed in the distal lateral radial physis following application of local anesthetic and surgical preparation of a pre-placed hole. All horses were evaluated weekly after surgery and screw removal was performed standing and under sedation when correction of the angular limb deformity was achieved. The mean time for screw removal was 46 days. No short- or long-term complications were identified. Findings indicate that placing a single transphyseal screw in the lateral aspect of the distal radial physis with the horse standing is a viable option to treat varus angular limb deformity of the carpus in horses.     

In Vivo Evaluation of Intramedullary Interlocking Nail Fixation of Transverse Femoral Osteotomies in Foals

Objective—To evaluate an intramedullary interlocking nail for stabilization of transverse femoral osteotomies in foals.
Study Design—A transverse osteotomy and restabilization with an intramedullary interlocking nail was performed on the right femur in three foals and the left femur in three foals. Animals—Six foals weighing 149 to 207 kg.
Methods—The femur was destabilized with a transverse middiaphyseal osteotomy and repaired with a 0.5-in (12.7 mm) interlocking nail. The implanted femurs were radiographed monthly until completion of the study 6 months after surgery. At the completion of the study, all foals were observed for evidence of lameness, gluteal thickness was determined by ultrasonographic measurement, and a necropsy was performed.
Results—Healing was satisfactory in all foals. Five of the six had osseous bridging of the osteotomy apparent radiographically by 3 to 4 months. The sixth foal had postoperative infection but was healed radiographically in 5 months. There was a mean decrease in gluteal muscle thickness of 6.6 mm ( P = .04) in the operated limb of the five foals that healed without complication. Two foals were lame at the completion of the project; one foal with varus deformities of the contralateral limb was mechanically lame, and another was grade 2/5 lame on the operated limb. On necropsy, there was circumferential enlargement of the diaphysis of all operated limbs with the majority of the callus at the cranial and medial aspects of the cortex. All nails were solid within the medullary cavity.
Conclusions —The intramedullary interlocking nail provided adequate stabilization for repair of the transverse osteotomy.
Clinical Relevance —Further investigation is warranted before use for stabilization of spontaneously occurring fracture configurations.     

Correction of angular limb deformity in two subspecies of flamingo (Phoenicopterus ruber) utilizing a transphyseal bridging technique.

Three hand-raised American flamingo (Phoenicopterus ruber ruber) chicks and one hand-raised Chilean flamingo (Phoenicopterus ruber chilensis) developed valgus angular limb deformities of the proximal tarsometatarsal bone. All flamingos underwent surgical correction to unequally retard the growth plate using transphyseal bridging. Positive profile pins were placed in the proximal epiphysis and distal to the growth plate in the metaphysis on the convex side of the affected tarsometatarsus. Various banding techniques were used in each flamingo to create tension. Three of the four flamingos responded in 7-14 days with correction or slight overcorrection of the valgus limb deformity. The fourth flamingo's leg deformity did not improve for reasons thought to be related to improper implant placement. Growth plate retardation by transphyseal bridging proved successful in correcting valgus limb deformity of the proximal tarsometatarsus. This technique may be considered as an option for correction of angular limb deformities of the proximal tarsometatarsus in flamingos less than 90-120 days of age.     

Farriery for the foal: A review part 1: Basic trimming

The extensive nature of this topic warrants this review paper to be divided into two parts: ‘Routine basic trimming in foals’ and ‘Therapeutic farriery in foals’. Hoof care in the first few months of life is serious business and should never be taken lightly. Good farriery is vital for the development of the hoof capsule and the conformation of the limb. Management of the feet and limbs during the juvenile period will often dictate the success of the foal as a sales yearling or mature sound athlete. Overall hoof care of a foal is often a joint venture between the veterinarian and the farrier. Part 1 of this paper will outline the concept of a footcare programme, examination of the foal's feet and limbs along with what constitutes good basic farriery to properly apply the trim. It will also emphasise the importance of maintaining a good veterinarian-farrier relationship - the farrier being responsible for basic trimming with veterinary oversight when necessary, and if orthopaedic disorders develop, the farrier will have significant input with therapeutic farriery.     

Treatment response and athletic outcome of foals with tarsal valgus deformities: 39 cases (1988-1997)

OBJECTIVE: To evaluate the response to various treatments and long-term outcome of foals with tarsal valgus deformities. DESIGN: Retrospective study. ANIMALS: 39 foals with tarsal valgus deformities. PROCEDURE: Data collected from medical records, included signalment, history, reason for admission, and clinical findings. Radiographic views of the tarsus were evaluated for incomplete ossification of tarsal bones and were classified as normal in appearance, type-I incomplete ossification, or type-II incomplete ossification. Treatment and athletic outcome were documented for each foal. RESULTS: Radiographic assessment revealed that 22 of 39 foals (56%) had concomitant tarsal valgus deformities and incomplete ossification of the tarsal bones. Eight of 19 foals with tarsal valgus deformities that were treated with periosteal stripping responded favorably. Foals < or = 60 days old were significantly more likely to respond to periosteal stripping than older foals. Five of 8 foals with tarsal valgus deformities that were treated with growth plate retardation responded favorably. Eleven of 21 foals with long-term follow-up performed as intended. Compared with foals with type-II incomplete ossification, foals with tarsal bones that had a normal radiographic appearance or type-I incomplete ossification were significantly more likely to perform as intended. CONCLUSIONS AND CLINICAL RELEVANCE: Foals with tarsal valgus deformities should have lateromedial radiographic views of the tarsus obtained to assess the tarsal bones for incomplete ossification, which will affect athletic outcome. Because foals with type-II incomplete ossification of the tarsal bones respond poorly to periosteal stripping alone, treatment by growth-plate retardation is recommended.     

Use of dynamic compression plates for treatment of tibial diaphyseal fractures in foals: nine cases (1980-1987)

The medical records of 9 foals less than 4 months old, with fracture of the tibial diaphysis, were reviewed. Open reduction was accomplished by use of 3 approaches; however, a cranial approach was preferred and was used in 7 foals. Two dynamic compression plates were implanted in all foals except the first of this series. The technique of plate luting was used in 7 foals and appeared to improve the ability of implants to resist failure. Complications after surgery included partial or complete failure of fracture fixation (n = 3 foals), osteomyelitis (n = 2 foals), angular limb deformity (n = 2 foals), minor dehiscence of the surgical wound (n = 3 foals), and mild extensor deficits of the injured limb (n = 4 foals). One foal was euthanatized 12 hours after surgery because of complete loss of fracture fixation. All other foals were discharged 10 to 295 days after surgery. One or both plates were subsequently removed in 7 foals. Follow-up information was obtained 6 to 36 months after discharge. Excellent results were reported for 6 foals, and good or fair results were reported for the remaining 2 foals.     

Evaluation of laparoscopic adhesiolysis for the treatment of experimentally induced adhesions in pony foals

OBJECTIVE: To assess the efficacy of laparoscopic adhesiolysis in the treatment of experimentally induced adhesions in foals. ANIMALS: 8 healthy pony foals. PROCEDURE: Celiotomy was performed and adhesions created at the jejunoileal junction and at sites 0.5 and 1 m proximal to this junction, using a serosal abrasion method. Ten days after celiotomy, exploratory laparoscopy was performed. Laparoscopic adhesiolysis was performed in the treatment group only (4 foals, randomly selected). Thirty days after the exploratory laparoscopy, a final laparoscopic examination was performed, and the foals were euthanatized. The number and characteristics of abdominal adhesions were recorded during laparoscopy 10 and 30 days after celiotomy and during necropsy. RESULTS: At 30 days after celiotomy, the number of adhesions in the control group was significantly higher than the number in the treatment group. In the control group, all adhesions observed during the exploratory laparoscopy were still evident at the final laparoscopy and necropsy. In the treatment group, adhesions did not form again after separation. During final laparoscopy and necropsy, a focal adhesion between the omentum and site of the initial laparoscope portal was observed in 5 of 8 foals. CONCLUSIONS AND CLINICAL RELEVANCE: The serosal abrasion model is useful for studying abdominal adhesions in foals. Laparoscopic adhesiolysis was an effective technique to break down experimentally induced adhesions in the early maturation stage of formation in pony foals. Studies are required to investigate prevention of de novo adhesions at the laparoscope portal sites.