Classification and management of the unstable total hip arthroplasty.
Seventy-five total hip arthroplasty revisions for instability were classified into 6 primary etiologies: I, acetabular component malposition; II, femoral component malposition; III, abductor deficiency; IV, impingement; V, late wear; or VI, unresolved etiology. The most common etiologies were cup malposition (type I; 33%) and abductor deficiency (type III; 36%). At a mean of 35.3 months, 11 redislocations occurred (14.6%). Acetabular revisions were protective against redislocation (P < .015). The number of previous operations (P = .0379) and previously failed constrained liners (P < .02) were risk factors for failure. Tripolar constrained liners demonstrated improved survivorship vs locking ring types (P < .02); cemented constrained liners failed more often than modular constrained liners (P < .0018). The highest risk of failure was in patients with abductor insufficiency with revisions for other etiologies having a success rate of 90%.
Department of Orthopaedic Surgery, Case Western Reserve University, Cleveland, Ohio 44116, USA.
Glenn D
GD
Wera
Nick T
NT
Ting
Mario
M
Moric
Wayne G
WG
Paprosky
Scott M
SM
Sporer
Craig J
CJ
Della Valle
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000706:statistics & numerical data*; D015984:Causality; D019544:Equipment Failure Analysis / Q000706:statistics & numerical data*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery; D006617:Hip Dislocation / Q000453:epidemiology / Q000209:etiology; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery; D006622:Hip Prosthesis / Q000009:adverse effects / Q000706:statistics & numerical data*; D006801:Humans; D007593:Joint Instability / Q000145:classification / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011859:Radiography; D012008:Recurrence; D012086:Reoperation; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology