Posterior intraprosthetic dislocation of cervical arthroplasty: illustrative case

BACKGROUND Cervical disc herniation is a common condition usually treated with anterior cervical discectomy and fusion (ACDF) or, more recently, with cervical disc arthroplasty (CDA). Both treatments offer similar clinical results. However, CDA has been found to offer fewer medium- to long-term complications as well as potential reduction of long-term adjacent disc degeneration. OBSERVATIONS A 40-year-old man was treated with cervical discectomy and arthroplasty due to a C6–C7 disc herniation with left C7 radiculopathy. After the treatment, his postoperative follow-up appointments were uneventful for 9 months. However, after 9 months, he reported cervical pain and a right C7 radiculopathy after neck extension. Imaging confirmed a posterior intraprosthetic dislocation, the first case reported to date. The patient was received emergency surgery under neuromonitoring, and the prosthesis was replaced by an ACDF and anterior plate. The insert presented a rupture of the anterior horn. The patient presented no preoperative or postoperative neurological deficit, and his follow-up review revealed no issues. LESSONS Posterior intraprosthetic dislocation is an extremely rare complication. It may occur with Mobi-C cervical arthroplasty in the case of rupture and oxidation of the polyethylene insert. Spine surgeons should be aware of this potential major complication.

Spontaneous Early Intraprosthetic Dislocation of 22 mm Skirted Femoral Head in Dual Mobility Hip Prosthesis: A Case Report

Introduction: There is a trend for increasing use of dual mobility hip designs for both primary and revision hip arthroplasty settings. It provides dual articular surfaces along with increased jump distance to increase the stability of construct. However, this design has some unique complications of its own which surgeons should be aware of especially intraprosthetic dislocation (IPD). Case Report: A 76-year-old lady presented to clinic with painful hip hemiarthroplasty after fracture neck of femur. She underwent revision surgery with dual mobility uncemented acetabular cup and femoral stem was retained as it was well fixed. She was mobilizing well and around 5 weeks post her surgery, developed pain in hip region and difficulty in weight-bearing. Radiographs showed eccentric position of femoral neck in the socket. A diagnosis of IPD was established and revision surgery was planned. Intraoperatively, metal head had dislocated from the polyethylene head and both components were resting in the acetabular socket. No macroscopic erosion of acetabulum was noticed. The polyethylene component and femoral head were retrieved. With previous failed dual mobility, decision was made to achieve stability with larger head size and lipped liner posteriorly. Conclusion: IPD is a rare occurrence and unique complication to dual mobility implants. This report highlights that patients can have IPD without fall or trauma. Keywords: Intraprosthetic dislocation, dual mobility cup, dislocation, total hip replacement.

Iatrogenic Intraprosthetic Dislocation of Dual Mobility Cup. Case Study

Intra-prosthetic dislocation of the dual-mobile acetabular cup is a rare complication. Most often, it is the result of wear of the polyethylene liner. It can also occur during a closed reduction of a dislocated dual-mobile cup. It is extremely important to recognize this complication immediately in order to avoid the consequences. This paper presents the first case of iatrogenic intraprosthetic dislocation at the Traumatology and Orthopaedics Department of the Military Medical Institute, our management of the case and suggestions for treating patients with a dislocation of the dual-mobile acetabular cup.

Intraprosthetic dislocation after a revision hip replacement: a case report

ABSTRACT BACKGROUND: The dual mobility cup (DMC) was initially design in 1974. It was designed to offer additional stability in total hip arthroplasty (THA) and to prevent dislocations. The dissociation of a DMC has been termed an intraprosthetic dislocation (IPD) and is a rare complication. It is defined as separation of the articulation between the polyethylene and head articulation in the DMC. As the utilisation of DMCs in orthopaedic surgery increases, we can expect an increase in this rare complication. We report a case of an IPD in the setting of revision hip arthroplasty in a 72-year-old female. CASE REPORT: The report is on a 72-year-old female patient who underwent revision hip arthroplasty. The articulation utilised was of the dual mobility type. Some eight months later she dislocated her hip. An attempted closed reduction under general anaesthesia with muscle relaxant was unsuccessful. Thereafter she was taken to surgery to perform an open reduction of the hip. Intra-operatively it was found that the dual mobility head had dissociated, with the polyethylene component remaining in the metal liner. A revision of the components was performed. DISCUSSION: We postulate on the mechanisms of dissociation of the dual mobility head. We review the current literature related to IPD and discuss the risk factors associated with this rare complication. CONCLUSION: The diagnosis of IPD is an indication for revision surgery of the DMC. When utilising a DMC, care should be taken to mitigate against the known risk factors for IPD. All dual mobility dislocations should be reduced under general anaesthesia with muscle relaxant Level of evidence: Level 4.. Keywords: intraprosthetic dislocation, dual mobility cup, revision hip arthroplasty