Proximal Suspensory Desmopathy in Hindlimbs: A Correlative Clinical, Ultrasonographic, Gross Post Mortem and Histological Study

Abstract

Summary Reasons for performing study It has been suggested that ultrasonography is unreliable for the detection of hindlimb proximal suspensory desmopathy (PSD) based on comparisons between ultrasonographic and magnetic resonance images. Objectives To compare ultrasonography with gross and histopathological post mortem examination in horses with PSD diagnosed based on ultrasonography and control horses. Study design Retrospective descriptive study. Methods Part 1: 19 horses with hindlimb PSD and 10 control horses were humanely destroyed. Twenty control limbs and 37 lame limbs were examined grossly and 40 suspensory ligaments (SLs) were examined histologically and graded blindly. Part 2: 3 horses with recurrent lameness after surgical management of PSD and 4 with PSD were assessed ultrasonographically and by gross post mortem examination. Results Part 1: ultrasonographic lesions were graded moderate in 31/38 (81.6%) and severe in 7/38 (18.4%) lame limbs; in 4/37 (10.8%) limbs adhesion formation between the proximal aspect of the SL and the accessory ligament of the deep digital flexor tendon was predicted. Gross post mortem and histological examinations of control limbs revealed no abnormalities. Gross post mortem examination revealed substantial adhesions between the proximal aspect of the SL and adjacent soft tissues in 10/37 (27.0%) lame limbs; in 10/37 (27.0%) limbs there were adhesions between the body of the SL and the mid plantar aspect of the third metatarsal bone, extending distally in 6 (16.2%) limbs. Histology revealed abnormalities (grades 1–3) of the collagenous tissue in 25/36 (69.4%) limbs; muscle was abnormal (grades 1–3) in 35/36 (97.2%) limbs and adipose tissue (grades 1–3) in 16/36 (44.4%) limbs. Part 2: adhesions between the SL and adjacent soft tissues were predicted ultrasonographically and confirmed post mortem. Conclusions Ultrasonography was reliable for the detection of SL pathology based on histology as the gold standard. Adhesions may be a reason for recurrent lameness after surgery.

Evaluation of the diagnostic accuracy of skeletal scintigraphy in lame and poorly performing sports horses

“…Avulsion fracture at the origin of the suspensory ligament on the plantaroproximal aspect of the third metatarsal bone is usually associated with increased radiopharmaceutical uptake and is sometimes seen in association with focal suspensory ligament disruption or sometimes more extensive damage . A diagnosis of proximal suspensory desmopathy or an avulsion fracture can readily be made with ultrasonography …”

Lameness originating from the proximal metacarpus/tarsus: A review of local analgesic techniques and clinical diagnostic findings

“…However, differentiation between radiographic and ultrasonographic findings of lame vs. clinically sound individuals presents a clinical challenge (Dyson ,; Labens et al . ; Dyson and Pinilla ). Furthermore, while evaluation of the proximal metacarpal or metatarsal region using radiography or nuclear scintigraphy may be useful in detection of bony changes, such as avulsion fractures, splint bone exostoses or cortical stress fractures (Brokken et al .…”

“…Radiography and ultrasonography may often be recommended first due to their widespread availability and relative affordability as diagnostic techniques. However, differentiation between radiographic and ultrasonographic findings of lame vs. clinically sound individuals presents a clinical challenge (Dyson 1991a,b;Labens et al 2010;Dyson and Pinilla 2015). Furthermore, while evaluation of the proximal metacarpal or metatarsal region using radiography or nuclear scintigraphy may be useful in detection of bony changes, such as avulsion fractures, splint bone exostoses or cortical stress fractures (Brokken et al 2007), MRI provides an advantage in distinguishing injuries arising from soft tissue as well as those with concurrent bony involvement (Labens et al 2010).…”

“…Abnormalities observed on radiographic and ultrasonographic examination of the proximal metacarpus and metatarsus may be subtle and difficult to interpret in terms of clinical relevance in the proximal metacarpus and metatarsus, further complicating lameness diagnosis of this region. Using histology as the gold standard, Dyson and Pinilla (2015) concluded that ultrasonography was reasonably reliable for detection of PSD pathology but had limited ability to detect gross adhesions. Therefore, following improvement in lameness after local analgesia of the proximal metacarpus and metatarsus, supplementary diagnostic analgesia of surrounding anatomic regions and/or advanced diagnostic imaging may be useful in diagnosis of lameness isolated to the subcarpal and subtarsal regions.…”

How to publish diagnostic imaging studies: Common mistakes and recommendations

“…The best design for a diagnostic imaging study aiming to compare a modality for its ability to diagnose a given clinical disease, such as MRI or ultrasound, to a pathologic process is a hypothesis driven, prospective study. Given that diagnostic imaging techniques usually aim to elucidate structural change, histopathology or surgery often serve as a gold standard and the diagnostic imaging modality under investigation can be interpreted in light of this gold standard . Major barriers to this approach can be the invasiveness of the gold standard and/or lack of access to adequate numbers of cases with the disease or injury being studied.…”