Box Rest Research Articles

Infrared Spectroscopy Can Differentiate Between Cartilage Injury Models: Implication for Assessment of Cartilage Integrity

In order to improve the ability of clinical diagnosis to differentiate articular cartilage (AC) injury of different origins, this study explores the sensitivity of mid-infrared (MIR) spectroscopy for detecting structural, compositional, and functional changes in AC resulting from two injury types. Three grooves (two in parallel in the palmar-dorsal direction and one in the mediolateral direction) were made via arthrotomy in the AC of the radial facet of the third carpal bone (middle carpal joint) and of the intermediate carpal bone (the radiocarpal joint) of nine healthy adult female Shetland ponies (age = 6.8 ± 2.6 years; range 4–13 years) using blunt and sharp tools. The defects were randomly assigned to each of the two joints. Ponies underwent a 3-week box rest followed by 8 weeks of treadmill training and 26 weeks of free pasture exercise before being euthanized for osteochondral sample collection. The osteochondral samples underwent biomechanical indentation testing, followed by MIR spectroscopic assessment. Digital densitometry was conducted afterward to estimate the tissue's proteoglycan (PG) content. Subsequently, machine learning models were developed to classify the samples to estimate their biomechanical properties and PG content based on the MIR spectra according to injury type. Results show that MIR is able to discriminate healthy from injured AC (91%) and between injury types (88%). The method can also estimate AC properties with relatively low error (thickness = 12.7% mm, equilibrium modulus = 10.7% MPa, instantaneous modulus = 11.8% MPa). These findings demonstrate the potential of MIR spectroscopy as a tool for assessment of AC integrity changes that result from injury.

Welfare considerations for management of horses on prolonged periods of box rest

Welfare considerations for management of horses on prolonged periods of box rest

Box rest and analgesia compared to arthroscopic debridement for lame horses with hindlimb subchondral lucencies

Category of research Treatment. Number and type of study designs reviewed Two relevant publications were found, both were retrospective case series. Strength of evidence Weak. Outcomes reported The success rate of horses returning to previous level of competition following arthroscopic debridement varies widely in the literature available, from 25–86%. While a study reports 64% return to soundness following rest, it is not clear which horses received strict box rest or paddock rest, the duration of the rest period, and whether non-steroidal anti-inflammatory drugs were also prescribed. It is also worth noting that all horses which undergo surgery will also undergo a period of box rest – which makes the two treatment options difficult to compare. Conclusion Newer techniques with better success rates are now available and should be considered in lieu of box rest or arthroscopic debridement. Across all treatments available, age remains an important factor with regards to return to soundness, with older horses having a poorer prognosis. Thorough examinations should therefore be performed to rule out concurrent conditions before deciding upon treatment options. How to apply this evidence in practice The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources. Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.

Optimising the welfare of equids on box rest: thinking outside the box

Restriction of equids to a stable for box rest is advisable for the management of acute physiological conditions. Confinement to a single stable is not an optimal environment for a horse and can create frustration and the expression of abnormal behaviours, which can indicate a reduced welfare state. Expression of aggression towards handlers or rebound behaviours when released from the stable can be a safety concern for handlers and gives the potential for reinjury. By reviewing the literature, we can consider what aspects of the environment can be adjusted to allow optimal expression of natural behaviour within the stable, subsequently reducing frustration and stress which will improve the welfare of the equine on box rest and potentially improve the safety of handlers.

Conservative treatment of an incomplete calcaneal fracture in a pony using a tarsal sleeve cast

SummaryA 9‐year‐old 390 kg games pony presented with acute onset of grade 5/5 (AAEP) right hindlimb (RH) lameness. During clinical examination, the source of lameness was localised to the tarsal region. Radiographic examination identified a closed, simple, nondisplaced, incomplete fracture of the calcaneal shaft. The pony was initially treated with box rest; however, despite an initial good response, the horse re‐presented with a grade 5/5 (AAEP) RH lameness, 2 weeks after initial presentation. The decision was made to treat the fracture using a tarsal sleeve cast extending from mid‐third of the tibia/crus to the level of distal metatarsus. The cast was replaced every 2 weeks and maintained for a total of 8 weeks. After cast removal, the horse was kept on strict box rest for 3 weeks. After discharge from the hospital, in‐hand walking exercise from the stable was commenced and gradually increased over a 4‐week period. The horse was then gradually reintroduced to small paddock turnout exercise for eight further weeks. The horse was able to return to full athletic function. Conservative treatment using a tarsal sleeve cast should be considered only in horses presenting an incomplete nondisplaced fracture of the calcaneal shaft.

Optimising the welfare of equids on box rest: thinking outside the box

Restriction of equids to a stable for box rest is advisable for the management of acute physiological conditions. Confinement to a single stable is not an optimal environment for a horse and can create frustration and the expression of abnormal behaviours, which can indicate a reduced welfare state. Expression of aggression towards handlers or rebound behaviours when released from the stable can be a safety concern for handlers and gives the potential for reinjury. By reviewing the literature, we can consider what aspects of the environment can be adjusted to allow optimal expression of natural behaviour within the stable, subsequently reducing frustration and stress which will improve the welfare of the equine on box rest and potentially improve the safety of handlers.

Longus capitis and rectus capitis ventralis minor rupture in a horse following general anaesthesia for a laryngeal tie-forward procedure

The authors present a case of a racehorse with acute respiratory distress, bilateral epistaxis and laryngeal swelling following a laryngeal tie-forward procedure. An emergency tracheostomy was performed following brief endoscopic...

Effect of circadian rhythm, age, training and acute lameness on serum concentrations of cartilage oligomeric matrix protein (COMP) neo-epitope in horses.

SummaryBackgroundMolecular serum markers that can identify early reversible osteoarthritis (OA) in horses are lacking.ObjectivesWe studied serum concentrations of a novel cartilage oligomeric matrix protein (COMP) neo‐epitope in horses subjected to short‐term exercise and with acute lameness. The effects of circadian rhythm and age were also evaluated.Study designLongitudinal studies in healthy horses and cross‐sectional comparison of lame and non‐lame horses.MethodsSera were collected from five horses before and after short‐term interval exercise and during full‐day box rest. Sera from 32 acutely lame horses were used to evaluate age‐related effects. Independent samples from control horses (n = 41) and horses with acute lameness (n = 71) were included. COMP neo‐epitope concentrations were analysed using custom‐developed inhibition ELISAs validated for equine serum. The presence of COMP neo‐epitope was delineated in healthy and osteoarthritic articular cartilage with immunohistochemistry.Results COMP neo‐epitope concentrations decreased after speed training but returned to baseline levels post‐exercise. No correlations between age and serum COMP neo‐epitope concentrations were found (r = 0.0013). The mean (±s.d.) serum concentration of COMP neo‐epitope in independent samples from non‐lame horses was 0.84 ± 0.38 μg/mL, and for lame horses was 5.24 ± 1.83 μg/mL (P<0.001). Antibodies against COMP neo‐epitope did not stain normal articular cartilage, but intracytoplasmic staining was found in superficial chondrocytes of mild OA cartilage and in the extracellular matrix of moderately osteoarthritic cartilage.Main limitations ELISA was based on polyclonal antisera rather than a monoclonal antibody. There is a sex and breed bias within the groups of horses, also it could have been of value to include horses with septic arthritis and tendonitis and investigated joint differences.ConclusionsThis COMP neo‐epitope can be measured in sera, and results indicate that it could be a biomarker for pathologic fragmentation of cartilage in connection with acute joint lameness.

Development of an equine carpal groove model to study early changes in osteoarthritis - a pilot study

Purpose: The cartilage groove model has been shown to be an effective model for investigation of early degenerative joint changes in various animal models, including recently in the equine metacarpophalangeal (MCP) joint. In this pilot study, we investigated: 1) if the groove model induces comparable cartilage degeneration in the equine middle carpal as in the MCP joint and 2) if a modified method for disrupting the collagen network without tissue loss, in combination with loading, also leads to cartilage degeneration. Methods: In two adult Shetland ponies, the dorsal aspect of the condyles of the third metacarpal bone (MCP joint) and the proximal surface of the radial facet of the third carpal bone (middle carpal joint) were grooved as described in the literature, using a hooked arthroscopic probe with a sharpened tip (“blunt grooves”). In the contra-lateral limb, grooves were made with a surgical mini blade that was clamped in a custom-made device (“sharp grooves”). After two weeks of box rest, the ponies were subjected to an eight-week training protocol on a treadmill. Clinical lameness was evaluated weekly. Synovial fluid was collected from the middle carpal joint before surgery and at two and 10 weeks postoperatively for analysis of glycosaminoglycan (GAG) levels and matrix metalloproteinase (MMP) activity. At 10 weeks, ponies were euthanized and osteochondral samples harvested for macroscopic, histologic and gene expression analysis of matrix components. Additionally, “fresh” grooves were made in the MCP and middle carpal joints of cadaver limbs to compare the microscopic appearance of grooves with and without a period of in vivo loading. Results: After 6-8 weeks post-operatively, regular stumbling and mild lameness were observed in both ponies during training. Macroscopically, grooves made by both techniques could be identified and adjacent tissue was affected, mainly in the carpal joints. Safranin-O stained histology sections clearly showed degenerative changes for cartilage with blunt grooves (i.e., loss of staining, fibrillation and cell clustering around the lesions), whereas only very mild changes were observed in cartilage with sharp grooves (Fig.1). Microscopy scores in both blunt and sharp grooved joints were higher at 10 weeks (12.4 and 7.3, respectively) compared with grooved cadaver joints (5.5 and 3.0) according to the OARSI equine microscopic grading system. Synovial fluid GAG concentrations dropped dramatically at two weeks after surgery, whereas MMP activity showed a clear increase. However, at 10 weeks, both markers returned to approximately baseline levels (Fig. 2). Carpal cartilage showed an upregulation of collagen 2, aggrecan and COMP, particularly where blunt grooves were made (Fig. 3). Conclusions: The groove model can be used in the equine carpus for the induction of cartilage degeneration. Contrary to the current paradigm, only disruption of the collagen network seemed not to lead to cartilage degeneration within 10 weeks after surgery. This would imply a crucial role for tissue loss. Synovial fluid GAG concentration and MMP activity do not seem to be sensitive markers once the initial inflammatory reaction has disappeared. A more extensive “omics-approach” could provide a better reflection of subtle changes in joint homeostasis in this early stage of degenerative joint changes. Confirmation in a larger number of animals is necessary, as is research on the long-term fate of the sharp lesions.

Equine Sesamoiditis: Report on one case

Sesamoiditis is the inflammation of the proximal sesamoid bones. The aetiopathogenesis of sesamoiditis is still open to discussion, while several therapeutic protocols have been put forward. This study presents the case of a l6year-old Dutch Warmblood gelding with sesamoiditis of the right forelimb. A right forelimb lameness (3/10), with a positive lower limb flexion test (5/10) was noted, and enlargement of the soft tissues of the right fore fedock. Based on the positive low four point nerve block, radiographic examination of the fedock revealed the presence of numerous radiolucent areas along the palmar aspect of the sesamoidean bones, but only minimal new bone formation on its base. An ultrasonographic evaluation of the suspensory ligament and the distal sesamoidean ligaments was made, something which did not detect any abnormalities. Phenylobutazone (4mg/kg i.v. SID) was administered for five days and, also, local hydrotherapy with cold water was used and the horse was given a 15- day box rest. The horse was re-examined three months following the initial inspection. The radiographic examination of the fetlock showed the same lesions with the initial examination. The second ultrasonographic evaluation, though, showed enlargement by 50% of the lateral branch of the suspensory ligament with loss of the normal outline. Moreover, anechoic areas were noted within the branch with calcification at its insertion site. To address the inflammation phenylobutazone (4mg/kg i.v.) was administered for ten days and, also, local hydrotherapy with cold water was used. Box-rest for 30 days was recommended. In the end of this period there was no inflammation in the fetlock region. A blister (TWYDIL liquid blister®) was used in order to resolve the chronic inflammation of the suspensory apparatus. The horse was then given three weeks of box rest and received correcting shoeing (egg- bar shoe with elevated heels and rolled- toe). It was then put in a gradually increasingexercise program.

Computed tomographic diagnosis of incomplete palmar cortical (fatigue) fracture of the third metacarpal bone in two young adult endurance horses

SummaryTwo young adult endurance horses were presented for investigation of sudden‐onset forelimb lameness during competition. Clinical examination revealed a severe forelimb lameness and pain on palpation of the proximal palmar metacarpal area. Initial radiographic survey of the affected forelimb was unremarkable in both cases. A week of box rest resulted in only a mild improvement in the lameness. A second radiographic examination did not reveal any significant abnormalities. In both cases, scintigraphic examination was suggested, but was declined by the owner, and the lameness had significantly improved after local infiltration of 3 mL of anaesthetic solution in the proximal suspensory region. Radiographic and ultrasonographic examinations of the carpus and proximal suspensory region were unremarkable in Case 2. Case 1 had increased thickness of the medial lobe of the proximal aspect of the suspensory ligament. A computed tomographic examination was performed and an incomplete longitudinal (fatigue) fracture of the proximal third metacarpal bone was detected. After 8 months of box rest and rehabilitation, re‐examination revealed resolution of the lameness in both cases. Advanced diagnostic imaging should be considered in young endurance horses with severe lameness during competition or training, in which radiographic and ultrasonographic examinations are unremarkable or do not explain the severity of the lameness. Computed tomography imaging is considered a useful diagnostic imaging technique to detect incomplete longitudinal palmar metacarpal cortical (fatigue) fractures due to its ability to provide excellent bone detail.

Acute instabiliteit van het ligamentum nuchae ten gevolge van cervicale neuromusculaire disfunctie bij een dressuurpaard

Een warmbloed-dressuurpaard (ruin) van tien jaar oud werd aangeboden met de klacht van acute instabiliteit van het ligamentum nuchae na vrije beweging in een paddock. Op basis van de klinische presentatie, orthopedisch en neurologisch onderzoek, medische beeldvorming en elektromyografie werd cervicale neuromusculaire disfunctie van de M. obliquus capitis caudalis aan de rechterzijde van de hals vastgesteld. Conservatieve therapie met corticosteroïden in combinatie met orale supplementatie van vitamine B1 en boxrust resulteerden na zes maanden in volledig herstel.

Description of the incidence, clinical presentation and outcome of proximal limb and pelvic fractures in Hong Kong racehorses during 2003-2014.

Few studies have described incidences of proximal limb and pelvic fracture (PLPF) in Thoroughbred racehorses occurring on race day and during training. Information regarding clinical presentations and future racing careers in cases of PLPF is limited. To describe the incidence, clinical presentation and outcome of PLPF sustained by horses in racing and training at the Hong Kong Jockey Club (HKJC) between 2003 and 2014. Retrospective cohort study. Horses with PLPF confirmed by nuclear scintigraphy, ultrasonography, radiography or post-mortem examination were identified using veterinary clinical records. Training and racing data for case horses were described. Incidences of fractures were estimated per 1000 horses in training and per 1000 race starts for fractures sustained during racing. Descriptive statistics were used to describe the study population. A total of 129 instances of PLPF were sustained by 108 racehorses. The most commonly fractured bone was the humerus (49.6%), followed by the tibia (29.4%). Nine horses sustained fatal fractures, eight of which occurred during racing. The incidence of fracture during racing was 0.30 per 1000 starts. Two-thirds of fractures occurred during training. The majority of horses presented with grade 3 lameness (n = 42 of 119 injury events, 35.3%). All horses presenting with grade 5 lameness sustained fatal injuries. Following noncatastrophic injury, all horses underwent box rest and 81 horses subsequently resumed racing; 45 of these won a race. Horses were retired at a median of 25 months (interquartile range: 15-36 months) after injury. Protocols for resting non-training racehorses at the HKJC and for recording rehabilitation regimens post-injury prevented the calculation of horse days at risk. The incidence of PLPF at the HKJC is low. Non-fatal PLPF is not necessarily a career-ending injury and many horses resume racing successfully following conservative treatment.

Clinical findings, treatment, and outcome in 11 dairy heifers with breakdown injury due to interosseous medius muscle rupture.

To describe the diagnosis, treatment, and prognosis of fetlock breakdown due to interosseus medius muscle rupture in cattle. Retrospective clinical study. Dairy heifers with unilateral or bilateral interosseus medius muscle rupture (n = 11). Breakdown injury due to rupture of the interosseus medius muscle was documented clinically, radiographically, and ultrasonographically. Breakdown was bilateral in 4 heifers (3 in forelimbs, 1 in hind limbs) and unilateral in 7 (all hind limbs). One heifer with severe bilateral hind limb breakdown was slaughtered and the remaining 10 were treated by transfixation pin cast (1 heifer), box rest (n = 2), and/or a cast and splint (7). Hyperextension of the fetlock and hyperflexion of the proximal interphalangeal joints during weight bearing were characteristic for interosseus muscle breakdown. Ultrasonographically, the origin and body of the interosseus muscle and the branches to the sesamoid bones were primarily affected by the rupture. Conservative treatment was successful (used for their intended purpose) in 8 of 9 heifers with a median lifespan of 32 months after discharge from the clinic (range 6-83). Rupture of the interosseus medius muscle in young cattle may be more common than previously suggested in the literature. Imaging with ultrasound allowed more detailed localization of lesions of the musculo-tendinous structure. Interosseus medius muscle rupture had a favorable prognosis when treated conservatively in these heifers.

Risk factors for equine laminitis: A case-control study conducted in veterinary-registered horses and ponies in Great Britain between 2009 and 2011

Laminitis is a highly debilitating disease of the foot known to have a complex and multifactorial aetiology of metabolic, inflammatory, traumatic or vascular origin. The disease has major welfare implications due to unrelenting pain associated with degenerative changes, which often necessitate euthanasia on welfare grounds. Despite this, there have been few high-quality studies investigating risk factors for equine laminitis, and only a limited number of risk factors have been previously investigated. The aim of this study was to conduct a case-control study of risk factors for active episodes of veterinary-diagnosed laminitis in horses and ponies attended by veterinary practitioners in Great Britain, based on multivariable statistical analyses.Questionnaires were received for 1010 animals, comprising 191 laminitis cases and 819 controls. Factors associated with an increased risk of laminitis were weight gain in the previous 3months, summer and winter months compared to spring, new access to grass in the previous 4weeks, box rest in the previous week, owner-reported history of laminitis, lameness or foot-soreness after shoeing/trimming, existing endocrinopathic (pituitary pars intermedia dysfunction and equine metabolic syndrome) disease and increasing time since the last anthelmintic treatment. Factors associated with a decreased risk of laminitis were increasing height (cm), feeding of additional supplements in the previous week and transportation in the previous week. Novel associated factors were identified that may aid in the management and prevention of the disease in the veterinary-registered equine population.

Autologous bone marrow mesenchymal stromal cells for regeneration of injured equine ligaments and tendons: A clinical report

The use of Mesenchymal Stromal Cells (MSCs) in orthopedic practice has recently and rapidly acquired an important role. Therapies based on the use of MSCs for the treatment of acute injuries as well as chronic inflammatory disorders are gradually becoming clinical routine. These cells have demonstrated intriguing therapeutic potentialities (i.e.: inflammation control, tissue regeneration and pathological scar prevention), that have been taken into consideration for use in both human and veterinary medicine. In particular, horses represent high performance athletes considered models for human pathologies since musculo-skeletal disorders frequently occur in this species. In the past, repair of tendon injures were performed by different methods. In particular, clinical therapy was based on ice application, bandage, box rest and controlled exercise. An alternative approach consisted on the use of corticosteroid (inflammation reduction) and other drugs (sodium hyaluronate, polysulphated glycosaminoglycans, beta aminoproprionitrile fumarate). Furthermore, surgical treatments like accessory ligament desmotomy, local irritation by line firing or pin firing were commonly used. More recently ultrasound, laser therapy, electromagnetic field therapy have been considered. Unfortunately, they did not allow complete tissue healing and quite often animals did not regain competitiveness. In order to minimize this inconvenience, the use of MSCs has been introduced as an alternative to the traditional approach since it represents a potential tool to improve tissue regeneration.Aim of this study was to evaluate the capability of MSCs to improve the functional outcome of horses affected by tendonitis and desmitis. Thirty-three breed and activity-matched horses affected by tendonitis or desmitis, were included in clinical trial scored for lesions and subdivided into two groups. Group 1 animals were treated with autologous MSCs, associated with platelet rich plasma (group 1). Bone marrow samples were collected from the sternum of the treated horses and processed in order to isolate MSCs. Following cell therapy, they were subjected to a rehabilitation period and their ability to resume training was evaluated. In this study, implanted MSCs caused no adverse reactions and thirteen out of the eighteen inoculated horses returned to race competitions. On the contrary, no improvement was seen in the twelve animals of group 2 treated with pin firing, that were not able to resume sport activity. In conclusion the clinical trial proves the safety of equine bone-marrow derived MSCs and a successful outcome of the treated animals that returned to their previous level of sport activity.

Management and outcome of fractures of the distal phalanx: A retrospective study of 285 horses with a long term outcome in 223 cases

A multicentre study of 285 cases was performed to enhance the management of distal phalangeal fractures on the basis of clinical evidence. The outcome after treatment was available for 223 of the cases. Horses with a non-articular type I fracture had a better prognosis (91.7%) for return to original or expected level of use than horses with an articular type II or III fracture (69.6% and 74.1%, respectively). The prognosis for types IV and V fractures was fair (57.7% and 57.1%, respectively) and for type VI good (80%). Horses with a hindlimb fracture had a significantly greater chance of a successful outcome. No significant association between age or time to start treatment and success rate was noted. The best treatment option for types I-III fractures was a conservative approach (box rest). Type IV fractures were best treated by arthroscopic removal of the fragment. Immobilisation of the hoof did not seem to influence outcome. Radiological findings and clinical healing were not accurately correlated and the re-commencement of training should be based on clinical rather than radiological findings. Complete osseous union of the fracture was not essential for a successful return to athletic activity.

Medial collateral ligament desmitis of the distal interphalangeal joint in the hindlimb of a horse: treatment with cast immobilisation

A 12-year-old show-jumping mare was presented for investigation of a chronic hindlimb lameness of 16 weeks duration. Perineural anaesthesia and ultrasonography localised the lesion to the medial collateral ligament of the distal interphalangeal joint of the left hindlimb. Treatment consisted of a heavily padded distal limb cast for 6 weeks, strict box rest and a strictly regulated hand walking program. Serial ultrasonographic examinations were performed throughout the rehabilitation period. Collateral ligament desmitis of the distal interphalangeal joint is a commonly diagnosed condition of the forelimb; however, hindlimb collateral ligament desmitis has been rarely reported. Ultrasonographic examination in this case was an invaluable diagnostic and follow-up tool. Immobilisation of the foot by means of a heavily padded distal limb cast allowed excellent healing of the ligament and is presented as a novel treatment for collateral ligament desmitis. At the time of writing the mare had returned to her previous level of exercise and was showing no signs of lameness.

A Lateral Approach for Screw Repair in Lag Fashion of Spiral Third Metacarpal and Metatarsal Medial Condylar Fractures in Horses

To describe a lateral approach for screw fixation in lag fashion of simple spiral medial condylar fractures of the third metacarpus/metatarsus (MC3/MT3). Case series. Thoroughbred racehorses (n=9). Nondisplaced medial MC3/MT3 condylar fractures (3 thoracic, 6 pelvic limbs), with mean length 126 mm (range, 91-151 mm) were repaired by internal fixation, under general anesthesia, using multiple 4.5 mm cortical screws inserted in lag fashion from the lateral aspect of the limb, using radiographic or fluoroscopic guidance. Horses were recovered from anesthesia in half-limb casts; 7 unassisted and 2 using a rope-recovery system. Horses had 2 months box rest, 1 month in-hand walking, and follow-up radiographic examination at 3 months. Horses recovered uneventfully from anesthesia. Five horses raced; 1 returned to training, was persistently lame, and was retired to stud; 2 were retired directly to stud; and 1 horse was lost to follow-up. MC3/MT3 medial condylar fractures were successfully repaired by screws inserted n lag fashion form the lateral aspect. Use of a lateral approach to medial condylar MC3/MT3 fractures allows screw insertion perpendicular to the fracture plane without interference with palmar/plantar soft tissue structures or from the splint bones. Although repair was performed under general anesthesia, the technique should be adaptable to application in standing horses.

MRI and CT diagnosis of acute desmopathy of the lateral collateral sesmoidean (navicular) ligament and long-term outcome in a horse

Clinical, magnetic resonance imaging (MRI) and computed tomography (CT) findings of acute desmopathy of the lateral collateral sesmoidean (navicular) ligament (CSL) in a 13-year-old Hanoverian mare are presented. On admission to the clinic the horse showed a grade 5/6 left front-limb lameness at the walk, pain on coffin joint manipulation, and coffin joint effusion. Despite a positive palmar digital nerve block, radiographs and ultrasonography did not indicate reasons for the severe clinical signs. However, MRI revealed damage to the CSL and bone marrow oedema of the navicular bone (NB), whereas a focal bone defect of the NB at the CSL insertion zone was demonstrated best by CT. The horse was managed with complete box rest and a fibreglass cast for four weeks followed by a controlled exercise program. Follow-up examination revealed no lameness at the trot three months later and the patient had fully recovered within six months.