SURGICAL-TREATMENT OF SUBCHONDRAL CYSTIC LESIONS OF THE 3RD METACARPAL BONE - RESULTS IN 15 HORSES (1986-1994)

Subchondral cystic lesions (SCLs) in the condyle of the third metacarp al bone (MCIII) were surgically treated in 15 horses, The median age a t presentation was 18 months (range 10 months-12 years) with 10 of 15 horses less than age 2 years, The SCLs were confined to the front limb s in all cases with 2 horses having bilateral lesions, Lesions were is olated to the medial condyle(s) of MCIII in 13 of 15 horses; a cystic lesion occurred in the lateral condyle in one horse and in the sagitta l ridge in one horse, One horse with bilateral lesions had an addition al cystic lesion located in the right medial femoral condyle, Fourteen of 15 horses had a history of moderate lameness attributable to the m etacarpophalangeal joint; the lesion was an incidental finding in one horse, Duration of lameness ranged from 4 weeks to 8 months and was ei ther acute in onset, or occurred intermittently and was associated wit h exercise, Fetlock flexion significantly exacerbated the lameness in all cases, Synovial effusion was absent in 8 (53%) cases. Cystic lesio ns were curetted arthroscopically in 12 horses, and through a dorsal p ouch arthrotomy in 3 horses, Concurrent osteostixis of the cystic cavi ty was performed in 7 horses, Two horses were treated arthroscopically for osteochondral fragmentation of the proximodorsal aspect of the pr oximal phalanx one year following surgical curettage of the SCL. Twelv e of 15 horses (80%) were sound for intended use following surgical tr eatment, Two horses did not regain soundness and follow-up information was unavailable for one horse, Total period of follow-up was 1-6 year s, Follow-up radiographic examinations were available for 9 horses, Mi ld periarticular osteophyte formation and enthesiophyte formation at t he dorsal joint capsular attachments was present in 5 of the 9 horses, Bony ingrowth of the cystic lesion was detectable in 8 horses and enl argement of the cystic cavity was observed in one horse, Based on the information gained from this study, it would appear that surgical trea tment of SCLs in the distal metacarpus can result in a favourable outc ome for athletic use.