Locking mechanism failure in the Harris-Galante porous acetabular component associated with recurrent hip dislocation

Treatment of Recurrent Total Hip Arthroplasty Dislocation Caused by Distorted Proximal Femoral Anatomy Due to a Previously Healed Trochanteric Fracture

Dislocation and instability of primary total hip arthroplasty (THA) is the leading cause for revision surgery, linked with significant financial burden and patient dissatisfaction. It is a multifactorial complication and requires accurate diagnosis and identification of the causative factors, as well as good preoperative planning for revision surgery. Despite all the best efforts, revision can lead to disappointing and frustrating results. We present a complex case of recurrent THA instability that required multiple operations before the identification of the main cause led to a satisfactory outcome. In addition, this is, to our knowledge, the first report of an Aesculap Plasmacup (Aesculap, Tuttlingen, Germany) liner dissociation and the first case where a previously well-united intertrochanteric fracture has been directly linked to recurrent instability. We aim to raise awareness of the complexity of such complications and the need for careful assessment of all the possible causes.

Prosthetic femoral head erosion through an acetabular component treated with revision and implant preservation

We present a case report of the rare complication of a femoral head prosthesis eroding through the acetabular liner and shell resulting in a clinical presentation of pseudo-dislocation. The patient presented with a 1-month history of progressive anterior and peritrochanteric hip pain without antecedent trauma. Radiographs demonstrated presumed hip dislocation with superior-posterior superimposition of the femoral head over the acetabular component. The patient underwent revision total hip arthroplasty with intraoperative evidence of extensive metallosis, osteolysis, and femoral head erosion through the acetabular polyethylene liner, acetabular shell, and implantation into the ilium. The femoral stem and acetabular shell were well-fixed, allowing for filling of the defect with bone void filler and cementation of a new polyethylene liner into the acetabular shell.

Pinnacle polyethylene liner dissociation: a report of 3 cases

We describe 3 cases of DePuy Pinnacle polyethylene dissociations, their presentations, and treatment. A 34-year-old female with arthritis secondary to dysplasia, a 51-year-old male with avascular necrosis of the femoral head, and a 57-year-old female with osteoarthritis were treated with total hip arthroplasty. Acute nontraumatic polyethylene liner dissociations occurred at 31, 42, and 2 months postoperatively. They were treated with component retention and modular femoral head and liner revision. The 51-year-old male subsequently developed a prosthetic joint infection requiring explant of his components. Although dissociation of polyethylene liners from the DePuy Pinnacle acetabular components is an uncommon complication, this problem may increase in prevalence with longer term follow-up, and vigilance is recommended.

Using Double-Contrast CT Arthrography to Confirm Suspected Dissociation of a Cemented Polyethylene Liner in the Setting of Revision Total Hip Arthroplasty: A Case Report

CASE

A 67-year-old woman who underwent a re-revision of a total hip arthroplasty with a cemented polyethylene liner fell 14 months after surgery. The patient had symptoms of pain and weakness; however, clinical, laboratory, and radiographic evaluation did not disclose fracture, infection, osteolysis, or component migration. Liner dissociation was suspected, and a double-contrast computed tomography (CT) arthrogram confirmed failure at the cement-liner interface. She underwent additional revision surgery and was doing well at the 3-year follow-up.

CONCLUSION

Double-contrast CT arthrography confirmed failure at the cement-liner interface and is an effective diagnostic tool in identifying suspected dissociations of cemented polyethylene liners.

Catastrophic wear in total hip arthroplasty. Complete wear-through of a metal-backed acetabular component: case report

A unique case of catastrophic wear of a total hip arthroplasty is presented. This brief report demonstrates the presentation of catastrophic wear of a modular acetabular component with protrusion of the femoral head through a modular metal-backed titanium cup. During the revision surgery, the polyethylene was found to have disengaged from the cup, and the cup was pistoning on the femoral neck. Significant metallosis and bone loss was found. The presence of severe metallosis mimicked bone on the preoperative radiograph and obscured the severity of the osteolysis seen on imaging.

Polyethylene exchange in a second-generation cementless acetabular component

Some have suggested that isolated polyethylene exchange in a well-fixed Harris-Galante II acetabular component (Zimmer, Warsaw, Ind) necessitates cementing the liner or complete revision because the locking mechanism is suboptimal. We reviewed 29 hip revisions during which the polyethylene was exchanged using the native locking mechanism. Mean follow-up was 5.1 years (2-13 years). Of the 29 patients, one had a disengagement of the revision polyethylene at 2.5 years. At the time of this patient's original revision, one of the tines was fractured, but a direct exchange was performed. There were 4 other revisions (one for loosening and 3 for instability). There were no other complications attributable to the direct polyethylene exchange and no further reoperations. This series suggests that polyethylene exchange with the Harris-Galante II prosthesis can be performed safely using the native locking mechanism in the absence of fractured tines.

The relationship between increased hip range of motion, wear, and locking mechanism failure in the Harris-Galante acetabular component

We performed both clinical and radiographic evaluations of 178 patients (190 hips) who had undergone cementless total hip arthroplasties using Harris-Galante I/II porous cups after an average 12-year follow-up period (range, 8-18 years). We revised 15 Harris-Galante I/II porous cups (7.8%), and the locking mechanism was broken in 10 revised cups (67%). There was a significant association between locking mechanism failure and linear polyethylene wear. We observed a significant positive correlation between linear polyethylene wear and increased ranges of motion such as flexion, adduction, and external rotation at the last follow-up visit after the primary operation. Increased ranges of motion seen in Asians induced higher linear polyethylene wear and locking mechanism failure due to impingement of the neck and cup.

Acute liner disassociation of a Pinnacle acetabular component

A primary total hip arthroplasty using a cementless Pinnacle cup and neutral Marathon polyethylene liner mated via a 32-mm cobalt chrome head to a Summit pore coated stem (Depuy, Warsaw, IN). At 23 months postoperative an acute disassociation occurred. This was resolved with a liner exchange to a 36-mm metal liner with a 36-mm metal head. The retrieved polyethylene liner was noted to have 3 of the 6 peripheral locking tabs sheared off.

The Harris-Galante porous-coated, hemispherical, polyethylene-lined acetabular component in patients under 50 years of age

We have reviewed 70 Harris-Galante uncemented acetabular components implanted as hybrid hip replacements with cemented stems between 1991 and 1995 in 53 patients whose mean age was 40 years (19 to 49). The mean follow-up was for 13.6 years (12 to 16) with no loss to follow-up. We assessed the patients both clinically and radiologically.

The mean Oxford hip score was 20 (12 to 46) and the mean Harris hip score 81 (37 to 100) at the final review. Radiologically, 27 hips (39%) had femoral osteolysis, 13 (19%) acetabular osteolysis, and 31 (44%) radiolucent lines around the acetabular component. Kaplan-Meier survival curves were constructed for the outcomes of revision of the acetabular component, revision of the component and polyethylene liner, and impending revision for progressive osteolysis.

The cumulative survival for revision of the acetabular component was 94% (95% confidence interval 88.4 to 99.7), for the component and liner 84% (95% confidence interval 74.5 to 93.5) and for impending revision 55.3% (95% confidence interval 40.6 to 70) at 16 years.

Uncemented acetabular components with polyethylene liners undergo silent lysis and merit regular long-term radiological review.

Harris-Galante II acetabular cup: a survival analysis

PURPOSE

To determine the survival rate of the Harris-Galante (HG) II cup and identify factors contributing to failure.

METHODS

271 primary total hip arthroplasties (THAs) performed between 1992 and 1999 in our hospitals using the HG II acetabular cup were retrospectively reviewed due to a high incidence of liner dissociation.

RESULTS

48 THAs were revised, 32 (67%) of which were due to liner dissociation. The Kaplan-Meier 10-year survival rate was 73%. Dislocation (p<0.001) and acetabular size (p=0.042) were independent predictors of acetabular component failure in the Cox's regression model.

CONCLUSION

The long-term outcome of the HG II cup is unsatisfactory. Although the HG II cup is no longer produced, numerous patients have this prosthesis in situ and should be reviewed regularly, as liner dissociation and retroacetabular osteolysis may occur.

A long-term follow-up study of the cementless THA with anatomic stem/HGPII cup with 22-mm head

The anatomic femoral component and Harris-Galante porous II (HGPII) cup were developed to provide more reliable bone ingrowth. We performed 20 cementless total hip arthroplasties (THAs) with anatomic stem/HGPII cup with 22-mm head in 14 consecutive patients, and evaluated the clinical and radiological results for a mean follow-up of 12.8 years. The all-anatomically designed stem provided excellent clinical and radiographic results. Four acetabular components underwent revision: three for fracture of the locking mechanism and wear of the polyethylene liner and one for the locking mechanism failure with dislocation of the HGPII cup. The abduction angles of the four revised acetabular components were apparently higher. The survivorship 13 years after surgery was 78%. Our findings show good long-term results using the anatomic femoral component, while the HGPII cup combined with 22-mm head seems to have poor durability due to locking mechanism failure.

The acetabular insert-metal backing interface: an additional source of polyethylene wear debris

In cementless acetabular arthroplasty, the interface between the metal backing and the ultra-high-molecular-weight polyethylene acetabular insert surface is a potential source of polyethylene debris. This study of 55 early-generation acetabular inserts found that severe wear of the convex insert surface correlates with osteolysis. Wear of the concave insert surface did not correlate strongly with osteolysis probably owing to prevalent micromotion and wear at the convex surface interface. Although concern over linear wear predominates with contemporary designs, if initial liner engagement is compromised or locking mechanism failure occurs with time, the convex insert surface again may become a significant source of debris contributing to osteolysis.

Polyethylene liner failure in second-generation Harris-Galante acetabular components

Polyethylene liner failure of cementless acetabular components has been reported to be the most common complication of current modular cups. We performed a retrospective review of 128 consecutive primary total hip arthroplasties in 111 patients who had a second-generation Harris-Galante cup (Harris-Galante II, Zimmer, Warsaw, Ind). The mean length of the follow-up period was 8.0 years (range 5-12.9 years), with 26 cups (20.2%) having undergone revision by that time. Twenty-two hips (17.3%) had failure of the polyethylene liner. We found that polyethylene liner failure remains the main cause of revision of this modular cup. The main difference between our population of patients and other populations that have used this cup and liner is our population's cultural inclination toward squatting and leg crossing, body positions that increased the risk of impingement and eccentric wear.

Cementation of a metal-inlay polyethylene liner into a stable metal shell in revision total hip arthroplasty

The purpose of this study was to evaluate the results of liner cementation into a stable acetabular shell using a metal-inlay polyethylene liner in 39 revision total hip arthroplasties. After an average of 2.8 years, 1 cemented liner dislodged from its metal shell at a postoperative 4 years. In the other 38 hips, mean Harris hip scores improved from 65 preoperatively to 86.9 at the final follow-up. Eighteen patients were rated as having excellent results, 17 as good, and 3 as fair. There were no changes in cup position and no cases of osteolytic lesion progression around the femoral and acetabular components in the last follow-up radiographs. Metal-inlay polyethylene liner cementation into a stable acetabular shell was found to provide an alternative option with short-term excellent results, and it also offers more liner options, the preservation of bone stock, and lower surgical morbidity.

Acetabular liner fixation by cement

Many situations in revision THA require the exchange of a PE liner in the setting of a well-fixed cementless acetabular shell. Unfortunately, a replacement liner is not always available, the locking mechanism of the metal shell may be damaged or incompatible with the desired liner, or the shell is malpositioned. Revision of a well-fixed cementless acetabular shell has been associated with considerable morbidity. This raises several questions: can a new PE liner be fixed in the existing shell using bone cement, and if so, which techniques can improve the end result, and in which patients should they be used? Biomechanical testing of cemented PE liners has shown initial fixation strengths that exceed conventional locking mechanisms. It is not known during what period this initial fixation will fail, but clinical reports with followup of as many as 6 years have shown survival in approximately 90% of cases. These studies have shown the importance of proper patient selection, accurate sizing of the PE liner, careful preparation of the substrate of the liner and the shell, and good cement technique. The potential advantages of this technique are less surgical morbidity, more rapid surgery and patient recovery, the ability to incorporate antibiotics in the cement, and more liner options.