Acetabular revision for recurrent dislocations: results in 14 cases after 3 years of follow-up

The use of a dual mobility cup in the management of recurrent dislocations of hip hemiarthroplasty

Background

Dislocation is one of the most frequent causes of failure of hemiarthroplasties of the hip, which is the most common treatment for femoral neck fractures in elderly patients. A revision with conversion to total hip arthroplasty is the gold standard in case of failure of closed reduction: however, the use of standard or modular components shows variable outcomes. The use of a dual mobility cup has been evaluated in patients with unstable implants, given the good outcomes obtained in primary and revision surgery. The aim of this study was to assess the results of revisions by dual mobility cups in unstable hemiarthroplasties.

Materials and methods

Thirty-one patients (mean age 75.4 years) were retrospectively evaluated between 2006 and 2010 after conversion to total hip arthroplasty with dual mobility cups for recurrent dislocations. The mean number of dislocations was 2.6 (range 2–5). The evaluation was performed by the American Society of Anesthesiologists physical function score (ASA) and the Harris hip score, and several radiologic criteria.

Results

The mean follow-up was 3.8 years. No recurrence of dislocation was recorded. The ASA score remained unchanged, and the mean Harris hip score improved from 62.2 before dislocation to 76.0 points postoperatively.

Conclusions

Dual mobility cups may be a useful option in the treatment of a hemiarthroplasty dislocation. No risk of a new revision due to instability after insertion of dual mobility cups resulted in our experience, and this option may be strongly considered in cases of revisions of unstable hemiarthroplasties.

Level of evidence IV.

The dislocating hip replacement - revision with a dual mobility cup in 56 consecutive patients

INTRODUCTION

Recurrent dislocations of hip replacements are a difficult challenge. One treatment option for recurrent dislocations is the use of a dual mobility cup. The aim of this study was to retrospective investigate the effect of dual mobility cups as a treatment for recurrent dislocations in a consecutive series. Materials and.

METHODS

56 consecutive patients were revised in the period November 2000 to December 2010. The mean age at revision was 72 years (SD 11, range 37-92)) and median number of dislocations before revision surgery were 4 (IQR, 2-11). In all cases, revision was made with a Saturne dual mobility cup (Amplitude, Neyron, France). The mean follow-up period was 44 months (SD 30, range 0.1-119).

RESULTS

One patient (1.8%) experienced a re-dislocation. Three patients (5.3%) had to be revised. One due to disintegration between the femoral head and inner shell, one due to loosening of the acetabular component, and one due to infection. Harris Hip Score improved from a mean of 76 before index surgery to 87 within one year after index surgery.

CONCLUSION

This study advocates the use of a dual mobility cup for treatment of recurrent dislocations of THR. However, studies with a longer follow up are needed in order to evaluate implant survival.

Revision for recurrent instability: what are the predictors of failure?

Dislocation is a common complication following total hip arthroplasty (THA). In this study, we evaluated treatment strategies in patients undergoing revision THA for instability. A total of 156 hips in 154 patients underwent revision THA for instability between 2000 and 2007 at our institution. Demographic data and surgical treatment used were analyzed to determine risk factors for failure. Revision treatments included acetabular components in 100 hips, liner exchange in 56 hips, and femoral and acetabular components in 13 hips. Thirty-three (21.2%) had further dislocation. Isolated liner revision (P = .004), previous revision arthroplasty (P < .05), and the use of a 28-mm femoral head were associated with higher failure rates. A total of 20.3% (12/59) of constrained liners failed. Isolated liner exchange, history of revision, and use of a 28-mm head were associated with failure in revision THA for instability.

Cup positioning in THA: current status and pitfalls. A systematic evaluation of the literature

The correct determination of cup orientation in THA regarding the intraoperative as well as the postoperative assessment due to the pelvic tilt and rotation with inexact incorporation of the pelvis is uncertain. The anterior pelvic plane (APP) seems to be the most reliable reference frame and computer-assisted navigation systems seem to provide the best tool for correct implantation to date. For the intraoperative assessment of the APP, the exact determination of the bony landmarks is mandatory. For the standard plain radiography, standardized positioning of the patient and approximation of pelvic tilt by a lateral view are mandatory. An additional CT must be carried out for certain indications. More emphasis has to be given to the individuality of pelvic tilt and range of motion.

Use of a dual mobility socket to manage total hip arthroplasty instability

Unconstrained tripolar hip implants provide an additional bearing using a mobile polyethylene component between the prosthetic head and the outer metal shell. Such a design increases the effective head diameter and therefore is an attractive option in challenging situations of unstable total hip arthroplasties. We report our experience with 54 patients treated using this dual mobility implant in such situations. We ascertained its ability to restore and maintain stability, and examined component loosening and component failure. At a minimum followup of 2.2 years (mean, 4 years; range, 2.2-6.8 years), one hip had redislocated 2 months postoperatively and was managed successfully without reoperation by closed reduction with no additional dislocation. Two patients required revision of the implant because of dislocation at the inner bearing. Technical errors were responsible for these failures. Three patients had reoperations for deep infections. The postoperative radiographs at latest followup showed very satisfactory osseointegration of the acetabular component because no radiolucent line or osteolysis was reported. Use of this unconstrained tripolar design was successful in restoring and maintaining hip stability. We observed encouraging results at short-term followup regarding potential for loosening or mechanical failures.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The dislocating hip arthroplasty: prevention and treatment

The dislocating hip is functionally impairing and leads to patient dissatisfaction. The etiology is multifactorial and may include component malpositioning, soft tissue laxity, and component or anatomical impingement. Initial treatment of dislocation usually consists of closed reduction followed by the use of an abduction pillow or brace or a knee immobilizer, although evidence to support these actions is limited. Operative intervention is generally reserved for patients with more than 2 dislocations and should aim to correct the cause of dislocation using a simple algorithm. Proper component positioning is key to prevention of further dislocation, but other tools include modular implants, jumbo heads, and increased offset. Finally, constrained acetabular components may be considered if a patient fails one of the above surgical options.

Constrained liners for recurrent dislocations in total hip arthroplasty

This study reports the results and complications from treating recurrent hip dislocations with a constrained liner (CL) after total hip arthroplasty (THA). Forty patients who had a CL inserted as a secondary prophylactic treatment were retrospectively reviewed after a median observation period of 27 months (range 7-77 months). During the observation period five patients had to be revised: one for deep infection and four on account of re-dislocations. Our results indicate that patients with recurrent THA dislocations can be treated with a CL and has a satisfactory low complication rate and a relatively low risk of re-dislocation.

Results of reoperation for hip dislocation: the big picture

Hip instability remains a costly complication of primary (3%) and revision (10%) procedures. In those with well-oriented components, instability may be anticipated in about 70% from advancement of the trochanter. Articular reorientation readily is affected by the use of modular cups with elevated rims. This has proven to be an effective strategy both to lessen the likelihood of an initial dislocation after both primary and revision procedures. It has also proven to be an effective strategy to treat the unstable implant, especially if cup orientation has been defined as the primary problem. Larger head sizes in the range of low-friction arthroplasty, such as 32 mm, are not any more stable than 22-mm diameter implants. Anatomic-sized heads as used in bipolar devices are effective in treating established instability in up to 90% of instances. The most popular current option is that of the constrained head/cup articulation. Good short-term results have revealed success in more than 90%. However, the effectiveness is design dependent, and the long-term effectiveness understandably is questioned as reports of mechanical failure begin to emerge.