Instability is a common indication for revision total hip arthroplasty (THA). However, even after the initial revision, some patients continue to have recurrent dislocations. This study investigates those at risk for recurrent dislocation after revision THA for instability at a single institution. Between 2009 and 2019, 163 patients underwent revision THA for instability at a single institution. Thirty-three of these patients required re-revision THA due to recurrent dislocation. Cox proportional hazard models with death as a competing event were used to analyze risk factors, including prosthesis sizing and alignment. Paired t-tests or Wilcoxon signed rank tests were used to assess patient outcomes (Veterans RAND 12 (VR-12) physical score, VR-12 mental score, Harris Hip Score, and hip disability and osteoarthritis outcome score for joint replacement). Duration of follow-up until either re-revision or final follow-up was a mean of 45.3 ± 38.2 months. The 1-year cumulative incidence for recurrent dislocation after revision was 8.7%, which increased to 19.6% at 5 years and 32.9% at 10 years postoperatively. In the multivariable analysis, high ASA score [HR 2.71], being underweight (BMI<18 kg/m2) [HR 36.26] or overweight/obese (BMI>25 kg/m2) [HR 4.31], use of specialized liners [HR 5.51–10.71], lumbopelvic stiffness [HR 6.29], and postoperative abductor weakness [HR 7.20] were significant risk factors for recurrent dislocation. Increasing the cup size decreased the dislocation risk [HR 0.89]. The dual mobility construct did not affect the risk for recurrent dislocation in univariate or multivariable analyses. VR-12 physical and HHS (pain and function) scores improved postoperatively at midterm. Patients requiring revision THA for instability are at risk for recurrent dislocation. Higher ASA scores, abnormal BMI, use of special liners, lumbopelvic stiffness, and postoperative abductor weakness are significant risk factors for re-dislocation.
Surgical treatment for osteonecrosis of the femoral head (ONFH) includes both joint-preserving techniques and joint replacement. Joint preservation is more effective in early-stage ONFH; thus, prompt diagnosis when the femoral head is still salvageable is an important clinical goal. We report a 20-year retrospective study that summarizes the proportion of patients diagnosed with early-stage versus late-stage ONFH at initial presentation to our practice. Our institutional database was reviewed to identify patients 18–65 years of age who were diagnosed with atraumatic ONFH in our clinic between 1998–2018. The Association Research Circulation Osseous (ARCO) system was used to stage ONFH, based on available imaging. Patients with prior surgical treatment for ONFH were excluded.Background
Methods
The posterolateral or posterior approach for total hip arthroplasty has the advantages of preserving the hip abductor musculature and providing good visualization during femoral preparation and component insertion. Although posterolateral approach is one of the popular approaches in hip arthroplasty, it has been reported high dislocation rate as a drawback. To compensate the drawback the repair of short external rotator of hip is thought to be important. Therefore, we investigated incidence of failed repaired short external rotator muscles, dislocation rate and time of failure between tendon to tendon and tendon to bone repair technique through prospective study more than 1 year follow up. We performed 213 hip arthroplasties in 202 patients from May 2012 to January 2015. After exclusion of 15 hips due to follow-up loss(9 hips), death(2 hips), greater trochanteric fragment displacement(3 hips) and severe contracted short external rotator(1 hip), we investigated 198 hips in 187 patients. 57 patients were male and 130 patients were female. The mean age of patient was 70.4 (32–98) years. Reattachment short external rotator with posterior capsule to postero-superior aspect of greater trochanter(tendon to bone group, 111 hips) or to the tendon(tendon to tendon group, 87 hips) was performed. Two No.26 metal wire markers were fixed at the greater trochanter tip and short external rotator tendon respectively with a distance less than 1.2cm, and the distance between two wire markers was observed at postoperative 1 day, 2 weeks, 3 months, and annually radiographs in neutral position. When the distance was more than 2.5cm or one of the wire markers was invisible, we defined them the failure of short external rotator repair. The mean follow up period was 28.8 (12–45) months.Purpose
Materials and methods
Proper rotational alignment of the tibial component is a critical factor in the outcome of total knee arthroplasty (TKA), and misalignment has been implicated as a major contributing factor to several mechanisms of TKA failure. In this study we examine the relationship between bony and soft tissue tibial landmarks against the knee motion axis (plane that best approximates tibiofemoral motion through range of motion). The kinematic motions of 16 fresh-frozen lower limb specimens were analyzed in simulated lunging and squatting. All the tendons of the quadriceps and hamstrings were independently loaded to simulate a lunging or squatting maneuver. All specimens underwent CT scan and the 3D position of the knee was virtually reconstructed. Ten anatomic axes were identified using both the intact tibia and the resected tibial surface. Two axes were normal vectors to either the medial-lateral plateau center or the posterior tibial surface. Seven axes were defined between the tibial tubercle (the most prominent point, center of the tubercle, or medial third of the tubercle) and soft tissue landmarks of the tibia (the medial insertion of the patellar tendon, the center of the PCL and ACL, and the tibial spines). The last axis was the Knee Motion Axis (KMA), which was defined as the longitudinal axis of the femur from 30 to 90 degrees of flexion.Introduction:
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