Suspensory Ligament Branch Injury Research Articles

Low-Field Magnetic Resonance Imaging Findings of the Fetlock Region of Nonracehorses

Low-field, magnetic resonance imaging (MRI) is an advanced imaging modality widely used to diagnose distal limb pathology in horses, but there are limited data regarding lesion distribution within the metacarpo/metatarsophalangeal joint (MCP/MTPJ) region in lame nonracehorses. The aim of this study was to describe the low-field MRI findings and lesion distribution in nonracehorses with MCP/MTPJ region pain. Clinical records from horses undergoing MRI of the MCP/MTPJ region between July 2016 and March 2023 were reviewed. Horses were included if pain causing lameness was localized to this region and conventional imaging failed to provide a definitive diagnosis. Eighty-four horses met the inclusion criteria. Soft tissues were affected in 76 (90.5%) horses, with suspensory ligament branch injuries being the most frequent (60.7%) soft tissue pathology identified. Osseous pathology was diagnosed in 51 horses. The subchondral bone (SCB) of the distal third metacarpal/metatarsal bone (MC3/MT3) was the osseous structure most frequently affected (40.5%), with 79.4% of these horses having lesions on the dorsal aspect of the bone. Osteoarthritis was present in 48 (57.1%) horses. The main limitations of the study were the lack of a standardized diagnostic analgesia pattern due to varying veterinary surgeon involvement, and the absence of bilateral magnetic resonance (MR) sequences in all limbs. MRI is a useful diagnostic tool to assess soft tissue structures in the MCP/MTP region, especially in horses with thick skin, which may make ultrasonographic imaging unreliable.

Does high-intensity laser therapy speed return to primary function in horses with suspensory ligament desmopathy?

PICO question In horses with a suspensory ligament branch injury, does high-intensity laser therapy (energy output greater than 500 mW) combined with conservative management, compared to conservative management alone, result in a faster return to primary function? Clinical bottom line Category research Treatment. Number and type of study deisgns reviewed The number and type of study designs that were critically appraised were two peer-reviewed studies: a non-randomised controlled clinical trial and a randomised controlled experimental study. Strength of evidence Weak. Outcomes reported The outcomes reported are summarised as follows: the two appraised studies report positive effects of high-intensity laser therapy (HILT) on equine tendon and ligament injuries as measured by pain to palpation, lameness, swelling and ultrasonographic and magnetic resonance imaging (MRI) evaluation of HILT-treated lesions. Conclusion In view of the strength of evidence and the outcomes from the studies the following conclusion is made: the two appraised studies provide only weak evidence to show that horses treated with high-intensity laser therapy (HILT) and conservative management return to primary function sooner than horses treated with conservative management alone. Issues of design, methodology, statistical analysis and reporting reduce the reliability and external validity of these studies. 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.

Histological tissue healing following high-power laser treatment in a model of suspensory ligament branch injury.

High-power laser therapy gained popularity recently as a regenerative treatment for tendinitis and desmitis in the horse. However, studies evaluating the effects of laser therapy on tissue repair at the histological level in large mammals are lacking. To evaluate the effects of high-power laser therapy on suspensory desmitis healing, using a model of suspensory ligament branch injury. In vivo experiments. Standardised lesions were surgically induced in all four lateral suspensory branches of 12 healthy Warmblood horses. Laser therapy (class 4, 15W) was applied daily on two of four induced lesions for four consecutive weeks. Horses were randomly assigned to either short-term study (horses were sacrificed after 4weeks) or long-term study (6months). Suspensory ligament samples were scored after staining with haematoxylin-eosin and immunostaining for collagen 1- collagen 3- and factor VIII. In the short-term study, significantly better (lower) scores for variation in density (17% above cut-off score in treated lesions vs. 31% above cut-off score in controls, P=.03), shape of nuclei (54% vs 92%, P=.02), fibre alignment (32% vs 75%, P=.003) and fibre structure (38% vs 71%, P=.02) were found in laser-treated lesions when compared to controls. Collagen 3 expression was significantly higher (32% vs 19%, P=.006) in control lesions. In both short- and long-term studies combined, parameters lesion size (44% vs 56%, P=.02) and shape of nuclei (53% vs 84%, P=.05) scored significantly better in treated lesions. Long-term, significantly better (lower) scores were found in the laser-treated group for lesion size (15% vs 45%, P=.008) and a higher percentage above cut-off score for density of the nuclei (27% vs 9%, P=.02), compared to controls. The model of suspensory branch injury is not an exact representation of clinical overstrain lesions. These results suggest that high-power laser therapy enables better lesion healing than conservative treatment.

An investigation into the occurrence of, and risk factors for, concurrent suspensory ligament injuries in horses with hindlimb proximal suspensory desmopathy

SummaryHindlimb proximal suspensory desmopathy (PSD) is a common cause of lameness or poor performance in horses and may occur alone or together with other suspensory ligament (SL) injuries in forelimbs or hindlimbs. The aims of this retrospective case‐control study (January 2009 to December 2018) were to describe the occurrence of, and identify risk factors for, concurrent SL injuries in horses with hindlimb PSD. Data concerning age, breed, sex, work discipline, height, bodyweight and work history were collected. Concurrent SL injuries were defined as forelimb proximal suspensory desmitis or SL branch injuries (≥grade 2 [0–3]) in any limb. Hindlimb PSD was graded mild, moderate or severe based on ultrasonography. Data were described, and multivariable logistic regression modelling was used to identify factors associated with concurrent SL injuries. Data were available for 923 horses with hindlimb PSD, 28.6% (n = 264) of which had concurrent SL injuries. Age category (≤5 years of age vs. ≥6 years of age; P = 0.008), bodyweight:height ratio (P = 0.001), breed (P = 0.05), symmetry vs. asymmetry of hindlimb PSD ultrasonography grade (P = 0.005) and asymmetry vs. symmetry of lameness grade (P = 0.02) were associated with concurrent SL injury in horses with hindlimb PSD. Compared with horses aged ≥ 6 years, younger horses (odds ratio [OR] 1.76; 95% confidence interval [CI] 1.2–2.7) were more likely to have concurrent SL injury. The risk for concurrent SL injuries increased for every unit increase in bodyweight:height ratio (OR 2.27; CI 1.4–3.7). Compared with Thoroughbred crosses, Warmblood crosses (OR 3.3, CI 1.4–7.8), Thoroughbreds (OR 2.9, CI 1.1–7.1) and Irish Draught Horses (OR 3.5, CI 1.3–9.9) were more likely to have concurrent SL injuries. Hindlimb PSD ultrasonography grade severity was not associated with concurrent SL injury. In conclusion, age, bodyweight:height ratio and breed influenced the risk for concurrent lesions of the SL ligament. Further prospective studies in young horses are warranted.

Surgical management of marginal tears/avulsions of the suspensory ligament branches in 29 Thoroughbred racehorses.

Suspensory ligament branch injuries are common in horses. Most of these injuries are grouped together and considered as a single pathologic entity. To report a specific injury of the abaxial margin of the suspensory ligament branches and to report its surgical management and outcome. Retrospective case series. All horses with suspensory ligament branch injuries over a 9-year period (2007-2015) were identified. Horses with injuries which, on ultrasonographic examination, appeared to have defects in the abaxial margin of the suspensory ligament branch, that were subsequently confirmed during surgery were selected. Twenty-nine cases fulfilled the inclusion criteria with a specific lesion location on the abaxial margin of the suspensory ligament branch. Nineteen horses raced successfully after surgery, nine returned to training but failed to race and one was lost to follow-up. The absence of a comparable population of non-surgically managed horses in this study means that the contribution of removing torn tissue cannot confidently be assessed. The location and morphology of injuries described in this study is consistent, which suggests aetiopathogenic commonality. This case series suggests this type of injury has an identity of its own, differs from other types of suspensory ligament branch injuries and represents a previously undescribed subgroup.

Mineralization can be an incidental ultrasonographic finding in equine tendons and ligaments.

Tendon/ligament mineralization is recognized in horses but information regarding its clinical significance is limited. The aims of this observational study were to report the structures most commonly affected by ultrasonographically detectable mineralization and, for these, determine frequency of diagnosis and key clinical features. Cases presented at our hospital in April 1999-April 2013 and September 2014-November 2015 were included: a total of 27 horses (22 retrospective, five prospective). Mineralizations were most common in deep digital flexor tendons (10) and suspensory ligament branches (eight), representing 10% and 7% (estimated), respectively, of horses diagnosed with injuries to these structures during the study. Two deep digital flexor tendon and three suspensory ligament branch cases showed bilateral mineralization. Deep digital flexor tendon mineralization was restricted to the digital flexor tendon sheath, most commonly in the proximal sheath (±sesamoidean canal), and seven of 10 cases involved hindlimbs. Suspensory ligament branch mineralization was visible in the same ultrasound window as the proximal sesamoid bones in 10/11 limbs and six of eight cases involved forelimbs. Previous corticosteroid medication was a feature of one deep digital flexor tendon and one suspensory ligament branch case. Mineralization was associated with lameness in some but not all limbs. Mineralized foci within the deep digital flexor tendon preceded hypoechoic lesion formation in two limbs. Of the cases with deep digital flexor tendon or suspensory ligament branch injury only, one of three and two of three cases, respectively, became sound. Findings indicated that tendon/ligament mineralization can be associated with lameness in some horses, but can also be an incidental finding.

Subclinical ultrasonographic abnormalities of the suspensory ligament branches in National Hunt racehorses.

Suspensory ligament branch (SLB) desmopathy is a common cause of lameness and an important cause of lost training in the Thoroughbred racing industry. Studies have assessed the impact of insertional injuries of the SLB on the careers of flat racehorses and established the prevalence of subclinical ultrasonographic SLB abnormalities in this population, but little work has investigated SLB injury in National Hunt (NH) racehorses. To investigate the prevalence of subclinical ultrasonographic SLB abnormalities in NH racehorses with no clinical signs or history of SLB injury and to establish the cross-sectional area (CSA) of SLBs in this population. Cross-sectional study using data collected from horses on an NH yard. Ultrasonographic examination of forelimb SLBs in 62 horses on a single NH yard was performed. Images were graded according to a previously reported system. CSA measurements were obtained from transverse images. Nineteen of 62 horses had at least one SLB with grade 2 ultrasonographic abnormalities. Grade 2 ultrasonographic abnormalities occurred more frequently in the medial than the lateral SLB (P = 0.05). The medial SLB insertional CSA was significantly larger (P<0.001) than that of the lateral SLB. Length of time on the yard (and therefore available veterinary history) is variable in this population. One in three NH racehorses without history or clinical signs of SLB injury had at least one SLB with a grade 2 ultrasonographic abnormality. The medial branch was over-represented. The medial SLB insertional CSA is larger than the lateral and thus comparison with the corresponding branch in the contralateral limb is recommended to avoid misdiagnosis of medial SLB enlargement.

Diagnosis and treatment of suspensory ligament branch injuries

The suspensory ligament branches are commonly injured in all types of horse used for all disciplines. Clinical examination is often indicative of an injury to the suspensory ligament branch, although diagnostic anaesthesia may be required to isolate the source of lameness. Standard radiography and ultrasonography techniques are adequate for diagnosis in the majority of cases. A wide range of pathology can occur to the suspensory ligament branch and the corresponding proximal sesamoid bone. Treatment should involve rest, controlled exercise and remedial farriery. Other adjunctive treatments are available, but evidence for their efficacy is lacking.

Association between sesamoiditis, subclinical ultrasonographic suspensory ligament branch change and subsequent clinical injury in yearling Thoroughbreds.

Sesamoiditis is a common radiological finding in yearling Thoroughbreds. The condition is believed to be associated with suspensory ligament branch injury (SLBI), which is known to affect racing performance. The presence of subclinical suspensory ligament branch change (SSLBC) in untrained yearlings has not been investigated. Associations between sesamoiditis, SSLBC and subsequent SLBI would allow more accurate prognoses to be made regarding the development of SLBI. They could also provide opportunity for intervention and prevention of SLBI. To test our hypotheses that untrained yearling Thoroughbreds with sesamoiditis would be more likely to have ultrasonographic findings of SSLBC and those horses with concurrent sesamoiditis and SSLBC would be more likely to develop clinical suspensory ligament branch injury with training. Prospective, cohort, observational study. Yearling Thoroughbreds located at a single training centre were evaluated at the onset of their training careers and for the next 9 months. Radiographic and ultrasonographic examination of bilateral forelimb proximal sesamoid bones and suspensory ligament branches was performed. Fifty horses were eligible, resulting in 200 forelimb sesamoid/suspensory ligament branch pairs. A significant relationship existed between possibly significant (PS) sesamoiditis and PS SSLBC (P<0.001). The odds ratio of sesamoids with PS sesamoiditis also demonstrating concurrent PS SSLBC was 5.1 (95% confidence interval 2.68-9.70, P<0.001). A significant relationship also existed between the concurrent presence of PS sesamoiditis and PS SSLBC and the subsequent development of clinical signs of SLBI (P<0.001, odds ratio 11.7, 95% confidence interval 4.1-33.4). The associations identified in this study highlight the importance of ultrasonographic examination of suspensory ligament branches in horses with PS sesamoiditis. This information should allow more accurate prognostic advice regarding potential SLBI development and also provide opportunities for intervention and prevention of clinical SLBI. THE SUMMARY IS AVAILABLE IN CHINESE - SEE SUPPORTING INFORMATION.

Clinical features, diagnostic imaging findings and concurrent injuries in 71 sports horses with suspensory branch injuries

SummaryThere are limited data concerning suspensory ligament branch (SLB) injuries in sports horses. This retrospective study aimed to describe the limb and mediolateral distribution of SLB injuries, the case history of injured horses, clinical signs, response to diagnostic analgesia, presence of other injuries, ultrasonographic features, radiological abnormalities and outcome. Case records of sports horses with ultrasonographic evidence of SLB injury (1998–2012) were reviewed. Ultrasonographic images were assessed subjectively and objectively. Descriptive statistics were used to describe horse data and injury distribution. Pearson's Chi‐square tests were used to test sidedness, forelimbs and hindlimbs, and medial and lateral branches. Pearson's Chi‐square tests were used to test for the ability to detect SLB enlargement by palpation and ultrasonography. Seventy‐one horses had injuries in 88 limbs, 42 forelimbs and 46 hindlimbs; 39/71 (54.9%) horses with only one branch injured, 18 (25.3%) with 2, 3 (4.2%) with 3, and 11 (15.5%) with 4. There was no significant difference in the proportion of injured medial and lateral branches, forelimbs or hindlimbs, left fore vs. right fore, or left hind vs. right hind. Forelimb injuries were overrepresented in event horses (76.2%) and hindlimb injuries in dressage horses (87.1%). Twenty‐eight horses had primary SLB injuries; 43 had other concurrent injuries in the same limb, 23 involving the suspensory apparatus. There was a significant difference (P = 0.011 in the ability to detect palpable enlargement of an SLB (60/171, 35.1%), compared with enlargement detected ultrasonographically (111/171, 64.9%). Periligamentous fibrosis was present in 78.7% of injured hindlimb SLBs and in 35.8% of forelimbs. Of horses with primary SLB injuries, 43.5% returned to full athletic function at their previous level for at least one year and up to 5 years. Periligamentous fibrosis or hyperextension of the fetlock adversely influenced outcome.

Do radiographic signs of sesamoiditis in yearlingThoroughbreds predispose the development of suspensory ligament branch injury?

Sesamoiditis is believed to be associated with injury to the suspensory branch attachment and is a common radiographic finding in yearling Thoroughbreds. No study has investigated relationships between yearling sesamoiditis and subsequent development of suspensory ligament branch injury (SLBI) in early racehorse training. To establish the prevalence of SLBI within a population of juvenile training racehorses and retrospectively investigate relationships between clinical signs of SLBI and sesamoiditis to determine if sesamoiditis is a risk factor for clinical suspensory branch injury. Retrospective case control study. Presale radiographs of 291 clinically normal yearling Thoroughbreds were reviewed for sesamoiditis and graded using 3 objective scales. Medical records encompassing the first year of race training were reviewed to identify cases of SLBI and the remaining unaffected controls from the cohort. Statistical analysis determined the relationship between sesamoiditis and the development of SLBI during training. The prevalence of SLBI was 9.97%. Case and control horses demonstrated a similar prevalence of sesamoiditis overall but SLBI cases demonstrated increased severity of sesamoiditis on yearling radiographs compared with unaffected controls. This significant relationship between sesamoiditis and cases of SLBI was only observed using one of the 3 scales. Using that scale, sesamoids exhibiting more pronounced sesamoiditis on yearling radiographs were 5 times more likely to develop SLBI in the adjacent suspensory branch (OR 4.56, 95% CI 2.18-9.53, P = 0.0001). This study reveals that the grading scale used is important when providing prognostic advice on the significance of radiographic signs of sesamoiditis. Evidence of significant sesamoiditis implies a 5 times greater risk of developing clinical SLBI with the onset of training. Clinicians should be aware that sesamoiditis may be an indicator of future SLBI in yearlings which are clinically normal at the time of sale.

Subclinical ultrasonographic abnormalities of the suspensory ligament branch of the athletic horse: A survey of 60 Thoroughbred racehorses

Ultrasonographic (US) abnormalities of the suspensory ligament branch (SLB) have been poorly investigated but can have considerable impact on market value and career path when encountered in athletic horses. There is a need for determination of the prevalence and relationship to clinical injury of these US abnormalities in the Thoroughbred (TB) racehorse. To establish the prevalence of, and the repeatability of an US grading system for, subclinical US abnormalities of the forelimb SLB in a population of UK TB flat racehorses. Ultrasonographic assessment of the forelimb SLBs of 60 TB racehorses free from history and clinical indication of SLB desmopathy in a single UK training yard was performed. Images were viewed independently by 2 blinded observers and graded for US abnormality. Interobserver agreement was assessed using Cohen's kappa statistic with 95% confidence intervals (95% CI). Prevalence of horses with subclinical US abnormality of the forelimb SLB of moderate severity was 6.7%. Medial branches were overrepresented. Inter observer agreement was substantial for US grade (kappa = 0.743; 95% CI 0.652-0.834) and almost perfect for appearance of sesamoid bone at ligament insertion (kappa = 0.817; 95% CI 0.66-0.98). The study reveals that a proportion of TB racehorses in flat training free from history or clinical signs of SLB injury have US abnormalities that could negatively impact on market value and career path. Clinicians should be aware that US abnormalities of the SLB may not always be related to clinical desmopathy. Further longitudinal studies are required to determine whether such findings are predictive for future injury.

Evaluation of a filter-prepared platelet concentrate for the treatment of suspensory branch injuries in horses.

Platelet preparations have become a treatment for soft tissue injuries in horses. This study evaluated a novel filter-based system to concentrate platelets and assesses its value in the treatment of suspensory ligament branch desmitis. Filtered platelet concentrate was prepared from 55 ml of venous blood obtained from 21 normal horses. Platelets and white blood cells in whole blood and filtered platelet concentrate were measured, as was platelet activating factor (PAF)-induced platelet-derived growth factor-BB (PDGF-BB) release. Eleven horses with 18 focal acute suspensory ligament branch injuries were treated intra-lesionally with autologous filtered platelet concentrate and evaluated clinically and ultrasonographically for one to three years. The increase in concentration of platelets in the filtered concentrate in comparison with whole blood (6.9 ± 1.9-fold) was significantly greater than the increase in white blood cells (3.8 ± 0.8-fold) (p <0.0001). There was no effect of sex or breed on platelet concentration. Platelets were responsive to PAF with >100-fold higher levels of PDGF release over basal levels. All hypoechoic lesions re-evaluated within three months had resolved. Five of the 11 horses returned to their previous level of work, one was exercising at a lower level, three were retired, one died for unrelated reasons, and one was still convalescing. Filtered platelet concentrate was easily and reliably prepared and injected into suspensory ligament branch injuries without short-term complications. This treatment was associated with rapid resolution of ultrasonographic lesions and lameness. Filtered platelet concentrate represents a convenient alternative for the treatment of suspensory ligament branch injuries.