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Background Polyethylene liner dissociation is an uncommon complication of hip replacement. Dissociation has been associated with particular acetabular component designs. This study reviewed acetabular liner dissociations in a specific modular cup with a Morse taper locking mechanism that has not been previously reported. Methods The senior author performed 655 primary total hip arthroplasties with one particular design of acetabular component using Class A polyethylene liners and metal head articulation. Cases with revision surgery performed for acetabular liner dissociation were reviewed. Results Seven of 655 patients with this cup underwent revision surgery for a dissociated liner. Liner dissociation occurred at a mean of 73 months postoperatively. Patients presented with new-onset hip pain or squeaking, 4 of which developed symptoms acutely. Two patients treated with polyethylene liner exchange into the same cup required a second revision surgery for recurrent dissociation. Conclusion Polyethylene liner dissociation is an infrequent but possible complication associated with modular acetabular components using a Morse taper locking. Providers should be vigilant with long-term follow-up of patients with this acetabular system for patient complaints of catching or squeaking. Patients treated for liner dissociation should not have a new liner placed into the same acetabular shell given the risk for further dissociation.

Slipped capital femoral epiphysis (SCFE) is a commonly encountered hip disorder. The goal of this study was to describe the incidence of missed contra-lateral SCFE as well as to identify risk factors. The authors hypothesized that contralateral slips are more often missed in patients with severe involvement of the treated side. After institutional review board approval was obtained, a retrospective chart review was performed of all pediatric patients who were treated for sequential and bilateral SCFE at a single institution during an 18-year period. Medical records were reviewed for demographic features and attending surgeon. Radiographs were reviewed for skeletal maturity, Klein's line, and severity of the treated slip. All radiographs were reviewed by 3 pediatric orthopedists. Contralateral SCFE was deemed present when consensus was achieved. Comparisons were made with Fisher's exact test, and P P =.0065). A contralateral slip was more likely to be present in patients who had a positive finding for Klein's line ( P Orthopedics . 2020;43(2):e114–e118.]