Distal splint bone fractures in the horse: an experimental and clinical study

Standing Surgical Management of Splint Bone Fractures in 13 Horses: A Comparison to Management Under General Anaesthesia

OBJECTIVE

 The aim of this article was to describe the technique and outcomes of standing surgical management of splint bone fractures and to compare outcome variables and hospitalization cost to a group with similar fractures treated under general anaesthesia.

STUDY DESIGN

 It is a single-institution retrospective study. Surgical technique, surgical time, hospitalization cost and complications were retrieved from the medical records of horses treated surgically for splint bone fractures (2008-2020). Owner telephone follow-up provided data about athletic outcome, client satisfaction and cosmetic appearance.

RESULTS

 Forty-nine horses (13 standing, 36 under general anaesthesia) with 57 fractures (18 contaminated and 39 non-contaminated) were included. Seven fractures were in the proximal third (4 standing, 3 under general anaesthesia), 18 in the middle third (5 standing, 13 under general anaesthesia) and 30 were distal (4 standing, 26 under general anaesthesia). No significant difference between groups in surgical time was found (p= 0.8). Average total cost was 522 CAN$ lower for the standing group for non-contaminated fractures (p= 0.02). Three horses of the general anaesthesia group demonstrated postoperative colic signs and one case of the standing group was re-operated due to sequestration. Based on follow-up information (range: 3.8-151.2 months), no significant differences in cosmetic and athletic outcomes were found between groups.

CONCLUSION

 Surgical management of splint bone fractures in the standing horse is a valuable alternative for horses selected based on behaviour. When compared to general anaesthesia, standing management of splint bone fractures did not alter the surgical time or outcome variables and avoided general anaesthesia-associated risks.

Clinical occurrence and radiographic diagnosis of distal limb lameness in equine

The objectives of this study was to evaluate the hospital occurrence of various radiographic lesions of the distal limb (bones and joints) lameness in equine and to evaluate the role of nerve and joint blocks for the localization of lameness in equine. All the equine lameness cases (117), presented during the one year study period that were subjected to radiographic evaluation, were investigated. Out of these, 20 equine lameness cases were subjected to systematic evaluation including nerve / joint blocks to confirm, whether the clinically or radiographically detectedlesion was the primary cause for the lameness or not. Out of 117, 78 equine (66.67%), were diagnosed with 124 radiographic lesions involving 101 limbs. The majority (62.8%) of the equines had single radiographic lesion, whereas the remaining animals were detected with multiple lesions involving one (15.4%) or more limbs (21.8%). Majority cases of equine lameness were recorded in winter season. Highest per cent lesions were recorded in hoofregion (25.81%) with more common involvement of fore feet (68.75%) and in mares (54.54%). Hock and fetlock regions were second (22.6%) and third (21.8%) most common regions for occurrence of equine lameness. Fetlock joint of hindlimb (63%) was more commonly affected than that of the forelimb. In this study, 16 nerve / joint blocks were applied in 15 horses and these were found helpful in confirming the lameness lesions in 66.7% cases. In conclusion, high prevalence of multiple lesions involving one or more limb poses great diagnostic challenge. Forelimb hoof and the hock were most frequently involved in distal limb lameness in equine. Periostitis and arthritis were most prevalent lameness causing lesions in equine. Physical examinations, nerve/ joint bocks and radiography complement each other in confirming the site of lesion causing lameness.

Evidence-based musculoskeletal surgery in horses

Musculoskeletal disorders comprise a large portion of the conditions treated by equine veterinarians. Surgical intervention is the treatment of choice in many cases. The body of literature describing and exploring surgical correction of musculoskeletal disorders in horses is steadily growing but still lacking. At this juncture, we can use what information we have with the understanding that as the quality of research advances, we should apply stricter standards to the evidence we use to answer our clinical questions.

Segmental ostectomy of the second and fourth metacarpal and metatarsal bones in horses: 17 cases (1993-2002)

OBJECTIVE

To determine clinical findings in and outcome of horses with fractures of the second or fourth metacarpal or metatarsal bone that underwent segmental ostectomy, leaving the proximal and distal portions of the bone undisturbed.

DESIGN

Retrospective case series.

ANIMALS

17 horses.

PROCEDURES

Medical records were reviewed, and information on signalment, affected bone, lesion type, surgical procedure, amount of bone removed, and surgical and postsurgical complications was obtained. Follow-up information was obtained through telephone conversations with owners, trainers, and referring veterinarians.

RESULTS

One horse had a fracture involving the distal third of the second metacarpal bone; 13 had fractures involving the middle third of the second metacarpal bone (n = 4), fourth metacarpal bone (5), or fourth metatarsal bone (4); and 3 had fractures involving the proximal third of the second (2) or fourth (1) metacarpal bone. Affected portions of the bones were surgically resected, leaving the proximal and distal portions undisturbed. All horses returned to previous performance levels without evidence of lameness. Cosmetic results were good to excellent.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that horses with a complicated injury of the proximal, middle, or distal portion of the second or fourth metacarpal or metatarsal bone may be successfully treated by means of segmental ostectomy of the abnormal portion of the bone.

The distribution of material properties in the equine third metacarpal bone serves to enhance sagittal bending

The distribution of material properties within the equine third metacarpal bone (MC3), and its possible effect on the mechanics of the structure, was quantitatively evaluated using single-load-to-failure compressive materials testing of specimens from ten horses. Bone samples from six regions within five proximodistal levels of MC3 were milled into right cylinders and compressed at a strain rate of 0.01 s-1. Diaphyseal MC3 bone material was stiffer, stronger, deformed less to yield and failure, and absorbed more energy to yield, than metaphyseal cortical bone material. Lateral and medial MC3 cortical bone material was stiffer and deformed less to yield and failure, than dorsal and palmar material. This distribution of material properties appears to increase the structural compliance in the sagittal plane, and may serve to enhance the predictability of the strain distribution during normal locomotion, as is provided in other bones by a sagittal curvature.

Suspensory ligament desmitis

The gross and functional anatomy of the suspensory ligament (SL) and its ultrasonographic variability are described. Injuries of the suspensory apparatus are divided into lesions confined to the proximal one third of the metacarpus or metatarsus (proximal suspensory desmitis and avulsion fractures), lesions of the body, and branch lesions. Complete breakdown injuries are also discussed. In view of the close association of the SL, the second, third, and fourth metacarpal or metatarsal bones, and the proximal sesamoid bones, associated bony lesions are also considered.

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.

Management of fractures and exostosis of the metacarpals and metatarsals II and IV in 25 horses

Twenty-five cases of fractures of the second and fourth metacarpal and metatarsal (splint) bones were reviewed. Fourteen fractures involved a thoracic limb and 11 involved a pelvic limb. Fractures of the proximal one-third of splint bones are reported in one of two forms: fractures that are closed, or fractures with a permanent or intermittent draining sinus. Thirteen of the fractures presented were closed fractures and the remaining 12 were open. All of the closed fractures were managed by surgical excision of the distal fragment and the exostosis at the fracture site, followed by primary surgical wound closure. Lag screw fixation of the proximal fragment was used in three cases. All of the open fractures were managed surgically by excision of the distal splint fragment and debridement of the contaminated fracture site. Primary wound closure was used in 11 of the 12 cases. All closed fractures healed by primary intention, and 10 of 13 were free from lameness at one year follow-up. The 11 open wounds which were operated and subsequently closed under suture healed by primary intention. The wound left open healed by granulation, scar contraction, and epithelialisation. Eight of these horses were sound one year later. The remainder of the open fractures were lost to follow-up.