Comparison of radiography and ultrasonography for the diagnosis of osteochondritis dissecans in the equine femoropatellar joint

Abstract

Reasons for performing study: Osteochondritis dissecans (OCD)lesions of the femoropatellar (FP) joint are diagnosed routinely by radiography, but lesions located in the trochlear groove or without accompanying subchondral bone changes can be difficult to visualise. Ultrasonography allows evaluation of articular cartilage and subchondral bone in the FP joint. Objectives:To document the radiographic and ultrasonographic appearance of OCD lesions in the equine FP joint, grade ultrasonographic lesions and compare their accuracy in the diagnosis of these lesions. Methods:The medical records of all horses diagnosed with FP OCD between 1995 and 2006 were assessed. Inclusion criteria included availability of both radiographic and ultrasonographic images. Lesion characteristics were evaluated in each trochlear ridge and trochlear groove. For assessment of the accuracy (sensitivity and specificity) of both imaging techniques in the diagnosis of OCD, only cases with an arthroscopic or necropsy examination were studied. Results: Twenty-one horses were included. OCD lesions were diagnosed by radiography (30/32 joints) and ultrasound (32/32 joints). The lateral trochlear ridge (LTR, 91%) and the medial trochlear ridge (MTR, 17%) were involved on radiography. The localisation on ultrasound examination was similar (97% LTR, 25% MTR). All but one lesion seen on radiography were also detected with ultrasound; 2 LTR and 3 MTR lesions, not seen on radiography were diagnosed by ultrasound and confirmed at arthroscopy or necropsy. The specificity was 100% regardless of the site and imaging procedure except for the distal third of the MTR (94% for ultrasound). The sensitivity varied, depending on lesion site. Conclusion: Ultrasonography is a valuable diagnostic tool to diagnose OCD lesions in the FP joint and more sensitive than radiography for lesions affecting the MTR of the distal femur. Clinical relevance: Ultrasound should be considered as a useful adjunct to radiography for diagnosing equine FP OCD, especially in cases of high clinical suspicion but equivocal radiographic findings. Images can be generated immediately when digital radiography is not available, permitting an immediate on-site diagnosis.

Diagnostic Sensitivity and Interobserver Agreement of Radiography and Ultrasonography for Detecting Trochlear Ridge Osteochondrosis Lesions in the Equine Stifle

“…Our findings also supported previous studies, in that we identified a higher sensitivity of ultrasound in evaluating osteochondrosis lesions of the femoropatellar joint. 9 There was better agreement between radiographic operators vs. ultrasonographers only for detecting lateral trochlear ridge lesions us- ing the LM view. Ultrasonography had a better agreement between operators than radiography for detecting lateral and medial trochlear ridge lesions when the Ca60 • L-CrMO view was used.…”

“…A site was considered positive for a lesion when fragmentation and/or a subchondral bone defect were present. The severity of the lesion was graded using a four-point system, based on criteria previously reported in dogs, 15 and horses, 9 where 0 = no lesion, 1 = cartilage irregularity with a visible superficial echogenic articular surface that shows concave deviation but is contiguous, 2 = a hyperechoic subchondral bone surface with moderate irregularity and discontinuity, and 3 = complete disruption of the echogenic articular surface and a hyperechoic subchondral bone with severe irregularity and discontinuity overlaid by heterogeneously echoic material. Only the results of the experienced operator were used for analyses of ultrasonographic sensitivity and specificity, and the ability of ultrasonography to predict severity of the lesions.…”

“…Because multiple lesions can be present, at least two radiographic views are recommended: lateromedial (LM) and caudolateralcraniomedial oblique (Ca60 • L-CrMO) views. 5,6 Diagnostic ultrasound has been found to be more sensitive than radiography for early identification of periarticular remodeling and osteophyte formation, and for detection of osteochondral lesions of the tarsus, 7, 8 stifle, 7,9 and metacarpo/metatarsophalangeal joints. 10 Ultrasonography has been used to detect cartilage fibrillation and irregularities of the trochlear surfaces of the femur in an experimental equine model of medial patellar desmotomy.…”

“…13,14 A recent retrospective study found subjectively that osteochondrosis lesion grades based on ultrasound are not predictive of lesion type based on arthroscopy or necropsy. 9 However, correlation of the severity of the lesions between ultrasonography and arthroscopy was not investigated. Interobserver agreement was also not investigated.…”

Desenvolvimento de protocolo de reabilitação no período pós-operatório inicial de artroscopia em equinos

“…É possível avaliar, além do osso subcondral, demais estruturas articulares, como a linha de cartilagem articular, membrana sinovial, inserções de ligamentos e líquido sinovial. Em estudo que se comparou a radiografia com a ultrassonografia no diagnóstico de lesões osteocondrais na articulação femoropatelar, encontrou-se melhor sensibilidade e especificidade com o diagnóstico ultrassonográfico de lesões que se encontravam no terço final das trócleas medial e lateral do fêmur (BOURZAC et al, 2009).…”