Ultrasonographic Findings in the Stifle Joint of Active Jumping and Dressage Horses

Abstract

ObjectiveUltrasonography (US) is frequently used to evaluate the equine stifle joint. Some soft tissue US findings are known to be clinically relevant, while others are considered incidental. These considerations are not always evidence-based. This study aims to describe the US findings observed in the stifle of clinically sound, active jumping and dressage horses. Procedures:To be included in this study, the horses had to fulfil 4 criteria: (1) in competition at least 1 time/month at national or international level, (2) in full work, (3) free of lameness, (4) no complains of the horse's performances. Both stifle joints of each horse were scanned systematically by US and US findings were recorded. Results:46 Warmblood horses fulfilled the criteria. US was normal in 21 horses, whereas abnormalities were detected in one or both stifles in 7 and 18 horses, respectively.Changes were seen in all compartments of the stifle joints: medial femorotibial joint (18 horses): osteophytes, effusion, subchondral cyst in the medial femoral condyle and lesions in the cranial meniscotibial ligament or medial collateral ligament; lateral femorotibial joint (4 horses): mild effusion, subchondral cyst in lateral femoral condyle; femoropatellar joint (16 horses): effusion, lesions in medial or intermediate patellar ligament or osteochondrotic lesions. Conclusion and Clinical relevance:Mild changes can be found ultrasonographically in the stifles of sport horses. Periarticular new bone formation was observed in 25% of the horses, apparently clinically not relevant. Lesions in the menisci, the tendinous portions of the popliteus muscle, long digital extensor muscle or peroneus tertius muscle or the lateral collateral ligament were not observed.

The equine patellar ligaments and the infrapatellar fat pad – a microanatomical study

“…Ultrasonographic examination of the PLs of case 2 – 5 and case 8 were unremarkable; the ligament shape, size, echogenicity and fiber pattern were within what has been reported elsewhere as normal and were bilaterally symmetric [ 1 – 3 , 6 ]. In case 6, the lateral PL had a bilateral symmetric heterogenic appearance at the tibial insertion with some anechoic areas observed in the transverse plane.…”

“…However, interpretation of ultrasonographic findings of the PLs may be problematic, as ultrasonographic appearance does not always correspond to clinical signs. Ligament thickening, hypoechoic areas or areas of heterogenic echogenicity, all of which could be interpreted as pathological lesions, have been reported in the medial and the intermediate PLs of sound warmblood riding horses in full work [ 6 ]. Moreover, in a study of horses with ultrasonographic lesions of the intermediate PL, ultrasonographic appearance seemingly worsened during a period of rest even though the lameness improved as horses were treated for their concurrent intra-articular stifle pathology [ 5 ].…”

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

“…These lines were suggested by Dyson (2002) to represent divisions between fascicle bundles but no histology was performed. Van der Vekens et al (2016) described a hypoechoic or heterogeneous area in the transverse plane in the mid to distal aspect of the ligament in active jumping and dressage horses. This area corresponded to a loss of fibre alignment in the longitudinal plane.…”

“…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.…”

“…The clinical significance of ultrasonographic findings of the patellar ligaments has, however, been challenged, as such findings have been observed in patellar ligaments of horses in full work without clinical signs of lameness (Van der Vekens et al, 2016). In humans, a clinical syndrome characterised by pain from and ultrasonographic lesions in the proximal posterior patellar tendon is known as 'Jumper´s Knee' or 'patellar tendinopathy' (Santana et al, 2022).…”