equis - Articles
Bone: subchondral cysts
Introduction
- Cause: trauma, osteoarthritis, OCD or infection.
- Signs: lameness +/- joint effusion.
- Diagnosis: intra-articular anesthesia, radiography, scintigraphy, computed tomography, MRI.
- Treatment: rest, systemic or articular anti-inflammatories and chondroprotectants, surgical debridement +/- bone graft or osteochondral graft (mosaicplasty), use of composite absorbable implants. Antibiosis if infection is involved.
- Prognosis: dependent on location and size of cyst.
- Commonly seen in equine bones.
- Predominantly a condition of younger horses.
- Does not always cause lameness.
- Can be articular or non-articular; most cysts which cause lameness are articular.
Presenting signs
- Variable joint effusion, lameness.
Age predisposition
- More commonly seen in younger horses.
- Two age groups affected:
- Younger horses: especially associated with OCD.
- Older horses: sudden onset.
Breed/Species predisposition
- Thoroughbred Thoroughbred, Warmbloods Dutch warmblood, Standardbreds Standardbred.
- Arabians Arab and Quarterhorses Quarterhorse for medial femoral condylar lesions.
- Uncommon in ponies.
Cost considerations
- Cost of surgery or long-term joint medication.
Pathogenesis
Etiology
- Subchondral cysts may be a manifestation of OCD Bone: osteochondrosis, osteoarthritis Musculoskeletal: osteoarthritis (joint disease), trauma or infection.
Pathophysiology
- OCD Bone: osteochondrosis:
- Instead of flaps of cartilage forming, the articular cartilage infolds.
- Infolded cartilage becomes necrotic and repair is not possible.
- Pain (and lameness) may be due to pressure of synovial fluid within the cyst, subchondral bone pain or synovitis caused by contents of the cyst released into the joint.
- Lesions frequently develop in areas of maximal weight-bearing.
- Can be created experimentally in predilection sites by focal full thickness cartilage defects.
- Joint trauma causing a focal full thickness cartilage defect.
- Osteoarthritis causing full thickness cartilage defect(s).
- Occasionally associated with a focal infectious process.
- Often bilateral.
Timecourse
- Not known what the time period is between development of the cyst and when clinical signs appear, but is probably related to the location of the cyst, underlying etiology, and the use of the horse.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Ravanetti P, Lechartier A, Hamon M & Zucca E (2021) A composite absorbable implant used to treat subchondal bone cysts in 38 horses. Equine Vet J 54 (1), 97-105 PubMed.
- Beccar Varela A M, Patipa L A & Eggleston R B (2014) Subchondral bone cyst of the apical portion of the proximal sesamoid bone as a cause of severe lameness in a Warmblood filly. Equine Vet Educe 26 (3), 126-131 VetMedResource.
- Greet T (2014) The first recorded subchondral cyst-like lesion of a proximal sesamoid bone. Equine Vet Educ 26 (3), 132-133 VetMedResource.
- Mair T & Sherlock C (2011) Osseous cyst-like lesions/subchondral bone cysts of the phalanges. Equine Vet Educ 23 (4), 191-204 VetMedResource.
- Helms Boone L & Peroni J (2009) Corticosteroid intralesional injection of subchondral bone cysts. Equine Vet Educ 21 (12), 638-639 Wiley Online Library.
- Del Chicca F, Kuemmerle J M, Ossent P, Nitzl D & Fuerst A (2008) Use of computed tomography to evaluate a fracture associated with a subchondral pedal bone cyst in a horse. Equine Vet Educ 20 (10), 515-519 VetMedResource.
- Goodrich L R & McIlwraith C W (2008) Subchondral bone cysts - not always an easy diagnosis. Equine Vet Educ 20 (10), 521-524 Wiley Online Library.
- Wallis T W, Goodrich L R, McIlwraith C W et al (2008) Arthroscopic injection of corticosteroids into the fibrous tissue of subchondral cystic lesions of the medial femoral condyle in horses: A retrospective study of 52 cases (2001-2006). Equine Vet J 40 (5), 461-467 PubMed.
- Arnold C E, Chaffin M K, Honnas C M, Walker M A & Heite W K (2008) Diagnosis and surgical management of a subchondral bone cyst within the intermediate tubercle of the humerus in a horse. Equine Vet Educ 20 (6), 310-315 VetMedResource.
- Jacquet S, Audigie F & Denoix J M (2007) Ultrasonographic diagnosis of subchondral bone cysts in the medial femoral condyle in horses. Equine Vet Educ 19 (1), 47-50 Wiley Online Library.
- Changoor A et al (2006) Mapping of donor and recipient site properties for osteochondral graft reconstruction of subchondral cystic lesions in the equine stifle joint. Equine Vet J 38 (4), 330-336 PubMed.
- Kay A T (2006) An acute subchondral cystic lesion of the equine shoulder causing lameness. Equine Vet Educ 18 (6), 316-319 VetMedResource.
- Smith M A et al (2005) Effect of age at presentation on outcome following arthroscopic debridement of subchondral cystic lesions of the medial femoral condyle: 85 horses (1993-2003). Equine Vet J 37 (2), 175-180 PubMed.
- Bodo G et al (2004) Autologous osteochondral grafting (mosaic arthroplasty) for treatment of subchondral cystic lesions in the equine stifle and fetlock joints. Vet Surg 33 (6), 588-596 PubMed.
- Garcia-Lopez J M & Kirker-Head C A (2004) Occult subchondral osseous cyst-like lesions of the equine tarsocrural joint. Vet Surg 33 (5), 557-564 PubMed.
- Textor J A et al (2001) Subchondral cystic lesions of the proximal extremity of the tibia in horses: 12 cases (1983-2000). JAVMA 218 (3), 408-413 PubMed.
Other sources of information
- McIlwraith W & Trotter G (1996) Joint Disease in the Horse. W B Saunders. pp 384-396.