Intermediate patellar ligament desmopathy often occurs in conjunction with other stifle abnormalities

Abstract

Intermediate patellar ligament (IPL) desmopathy is a relatively uncommon injury previously reported to have a poor prognosis for return to athletic activity. There is little documentation of the clinical and ultrasonographic features, clinical significance, and outcome for return to work following IPL injury in horses. The aim of this retrospective descriptive study was to describe the clinical and ultrasonographic features of IPL desmopathy, its association with other injuries of the stifle, and outcome for return to work following injury. Forty‐two stifles with an ultrasound diagnosis of IPL desmopathy over a 5‐year time period were included. Data regarding signalment, clinical presentation, diagnostic imaging findings, treatment, and outcome are described. Intermediate patellar ligament desmopathy occurred most commonly in the midbody (35/42; 83%) of the ligament and lesions were predominantly hypoechoic discrete tears (31/42; 74%) that were obliquely oriented in a craniolateral to caudomedial direction (28/42; 67%). Rarely (1/42; 2%) was IPL desmopathy the only ultrasonographic abnormality detected. Of 13 horses that underwent recheck ultrasound examination, the majority (11/42; 85%) either did not improve or worsened ultrasonographically. Despite this, of 25 horses with long‐term follow‐up, 23 (92%) returned to work, 16 at the same level or higher. A variety of treatments were utilized. The clinical significance of IPL desmopathy is difficult to determine because it is usually found in conjunction with other stifle abnormalities. Although IPL desmopathy rarely shows ultrasonographic improvement over time, prognosis can be good for return to work.

Patellar ligament desmopathy in the horse – a review and comparison to human patellar tendinopathy (‘Jumper’s knee’)

“…than in horses performing in other disciplines (Dyson, 2002b). However, in the retrospective study by Hoaglund et al (2019), 21 horses (51%) were of Quarter or Paint horse breed; 23 horses (56%) performed in non-jumping disciplines; and only nine horses (22%) were hunters/jumpers/eventers. In this population, 9 of 10 horses in which no abnormal findings were detected on a stifle ultrasonographic examination 6 months prior, ultrasonographic signs of intermediate patellar ligament desmopathy was detected following an extended period of rest (Hoaglund et al, 2019).…”

“…However, in the retrospective study by Hoaglund et al (2019), 21 horses (51%) were of Quarter or Paint horse breed; 23 horses (56%) performed in non-jumping disciplines; and only nine horses (22%) were hunters/jumpers/eventers. In this population, 9 of 10 horses in which no abnormal findings were detected on a stifle ultrasonographic examination 6 months prior, ultrasonographic signs of intermediate patellar ligament desmopathy was detected following an extended period of rest (Hoaglund et al, 2019). Intermediate patellar ligament injury may in some horses be associated with upward fixation of the patella or previous ligament desmotomy for treatment of upward fixation of the patella (Dyson, 2002b).…”

“…Of the three equine patellar ligaments, desmopathy of the intermediate ligament is more common (Dyson, 2002b;Reef, 1998). In a retrospective study reviewing ultrasonographic findings of the intermediate patellar ligament (2010)(2011)(2012)(2013)(2014)(2015), findings compatible with intermediate patellar ligament desmopathy were found in 41 horses, representing 18% of the study population (Hoaglund et al, 2019). Of note was the high occurrence of concurrent abnormalities; in only one stifle was the intermediate patellar ligament desmopathy the sole abnormal ultrasonographic finding.…”

“…Although ill-defined entities such as ligament laxity have been believed to cause lameness, true ligament pathology such as patellar ligament desmopathy has been regarded as an uncommon condition in horses. However, since the first published case series describing ultrasonographic characteristics of normal and abnormal patellar ligaments, more recent reports indicate that changes in echogenicity and fibre disruptions of the patellar ligaments are identified with increasing frequency, reported in 4-18% of horses undergoing ultrasonographic examination of the stifle (Dyson 2002b;Gottlieb et al, 2016;Hoaglund et al, 2019;Van der Vekens et al, 2016). This apparent increase is possibly reflecting improvements in diagnostic ultrasound techniques and equipment.…”

Highlights of recent clinically relevant papers

“…This retrospective descriptive study by Elizabeth Hoaglund and colleagues in the USA aimed to describe the clinical and ultrasonographic features of intermediate patellar ligament (IPL) desmopathy, its association with other injuries of the stifle and outcome for return to work following injury .…”