MRI Shows Biologic Restoration of Posterior Soft Tissue Repairs after THA

Although posterior capsule repair reduces the incidence of dislocation after THA, radiographic imaging studies suggest a high failure rate of the repair. Using MRI, we prospectively followed patients to evaluate the integrity of the posterior soft tissue repair after primary THA. Thirty-six patients (21 men, 15 women) underwent arthroplasty using a standard posterior approach. The posterior capsule and external rotators were repaired as separate layers using nonabsorbable sutures through two drill holes in the greater trochanter. Patients observed postoperative hip precautions for 6 weeks after surgery. All patients underwent initial MRI between postoperative Days 2 and 4. Thirty patients returned for followup MRI 3 months after surgery. At 3 months followup, the posterior capsule remained intact in 27 of 30 patients (90%) and the quadratus femoris repair remained intact in 29 of 30 patients (97%). Thirteen of 30 piriformis tendon repairs (43%) and 17 conjoined tendon repairs (57%) showed a gap between the hypointense tendon end and the greater trochanter greater than 25 mm. Our data show repaired posterior soft tissues provide a biologic scaffold allowing formation of a posterior pseudocapsule. Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.