Introduction

Total hip arthroplasty (THA) instability is well documented to be more common in specific demographic groups. We report a retrospective analysis of the use of a dual mobility implant for primary hip replacements in selected patients at risk for dislocation. The aim of this study was to assess the long-term clinical and radiologic features associated with the dual mobility cup in case of primary THA.

Introduction

The value of collared stems for uncemented implants remains controversial. Some comparative studies have demonstrated advantages of collared stems regarding the potential for subsidence. Other studies with longer follow-up have shown no adverse effect of the use of a collar regarding the femoral component survivorship. To date, the adequate size of the collar with regards to the anatomy of the proximal femur has never been studied.

The goal of this study was to assess whether the size of the collar needs to be adjusted according to the size of the femoral component used, and according to the use of a standard or a lateralized component.

Introduction

Primary mechanical fixation and secondary biologic fixation determine the fixation of an uncemented femoral component. An optimized adequacy between the implant design and the proximal femur morphology allows to secure primary fixation.

The femoral antetorsion has to be considered in order to reproduce the center of rotation.

A so-called «corrected coronal plane » including the center of the femoral head has therefore been defined. The goal of this study was to evaluate the proximal metaphysal volume and to design a straight femoral component adapted to this corrected coronal plane.

Introduction

Revision procedures for unstable total hip arthroplasty have been reported with high failure rates. Many options have been proposed in such challenging cases, including dual mobility. The purpose of this retrospective study was to assess the clinical and radiologic features associated with the dual mobility cup in case of revisions for instability.

Introduction

Despite improvements in prosthesis design, the clinical outcome of total hip arthroplasty still has 10% failure rate after 10 years. Component malpositioning can lead to instability, impingement, excessive wear and loosening. Computer-assisted procedures are expected to improve the accuracy of component positioning, and therefore the long-term outcome. We present an original hip navigation system that allows controlling leg lengthening, offset and stability without the use of the pelvic anterior plane.

Introduction

Reoperations to manage unstable total hip arthroplasty are reported with a high failure rate. The dual mobility cup (figure 1) (mobile polyethylene component between the prosthetic head and the outer metal shell) is a useful option in such cases. The purpose of this retrospective study was to assess the clinical and radiologic features associated with the dual mobility cup.

Purpose of the study: The ceramic-on-ceramic bearing for total hip arthroplasty (THA) has been widely used in Europe for many years. There have however been few publications on its long-term outcome. The purpose of this study was to examine the outcome at nine years follow-up of 100 THA implanted without cement using a ceramic-on-ceramic bearing.

Material and methods: The first 100 ceramic-on-ceramic THA implanted from November 1999 in our unit in patients aged less than 65 years were studied. The clinical assessment included the physical examination with search for complications and the Harris and Postel-Merle-d’Aubigné scores noted preoperatively and at last follow-up. The radiographic assessment was performed by two surgeons (double reading) to search for peri-prosthetic lucency, osteolysis, ossifications and implant migration. The state of the calcar was noted. The Delee-Charnley classification was used to classify the lucent lines for the acetabulum and the Gruen McNiece and Amstutz classification for the femur.

Results: Among the 100 THA, 20 patients were lost to follow-up. The Harris score was 42.6 (29–55) preoperatively and 93.9 (67–100) at last follow-up. The PMA was 8 (5–11) preoperatively and 16.7 (9–18) at last follow-up. One hip was revised to change the acetabular implant at five years. There were six early dislocations [one episode (n=4), two episodes (n=2)], one late dislocation, and two episodes of subluxation without recurrence. There were no fractures of the femoral head. The radiographic analysis identified moderate bone absorption of the calcar without real osteolysis in nearly all of the patients. For a few patients, a lucent line seen early postoperatively had disappeared at last follow-up. No implant migration (cup, stem) was noted.

Discussion: The clinical and radiographic outcomes are in agreement with the literature. The relatively high rate of dislocation can be explained by the diverse levels of experience of the surgical teams. The prostheses presenting dislocation did not have an unfavourable outcome, particularly radiographically.

Conclusion: These clinical and radiographic results at nine years follow-up, and the current systematic use of computer assisted navigation for optimal implant positioning favour continuation of the implantation of the ceramic-on-ceramic bearing in patients aged less than 65 years.

Reoperations for total hip arthroplasty instability are reported with high failure rates. The “dual mobility” socket is an attractive option in such cases. The goal of this retrospective study was to assess the clinical and radiographic features associated with such a design.

Fifty four unstable total hip arthroplasties (35 females, 19 males) were revised using a “dual mobility” socket at our institution between March 2000 and June 2005. Mean age at reoperation was 66.5 year old (range, 35.7 to 98.7). Harris Hip Score was used to assess the revision procedures’ outcome, and complications were determined by detailed review of the patient’s records. Anteroposterior and lateral radiographs of the involved joint were reviewed to assess the position of the prosthesis and to look for osteolysis and signs of loosening of the implant.

Mean follow-up was 4 years (range, 26 to 81 months). At last review 4 patients had died and one was lost to follow up. Postoperatively there was a significant improvement of the Harris Hip Score. Among the surviving patients, one (2%) redislocated and was successfully managed with closed reduction. This patient remained stable at latest follow-up. There were 3 revisions for deep infection, and 2 for dissociation of the bipolar component. Technical errors were found to be conducive to these dissociations. No cup required a revision for aseptic loosening. No radiolucent lines around the components and no osteolysis were observed at latest follow up.

The “dual mobility” socket is a highly effective option to manage unstable total hip arthroplasty. Unlike constrained devices, such components did not raise any concern regarding the potential for loosening and for osteolysis. Longer follow up is needed to confirm these results.

Purpose of the study: An unstable hip prosthesis is a therapeutic challenge. The prevalence of revision is 5 to 26.6% in the literature. We evaluated the contribution of double-mobility implants for revisions of unstable hip implants.

Material and methods: This series was composed of 45 patients who underwent revision between January 2000 and December 2003 for hip instability (44 dislocations, 1 subluxation). The same implant was used for all patients, either for the first-intention version (press-fit or cemented), or for the revision version (press-fit). For certain patients, the first-intention implant was cemented in an armature. The series included 28 females and 17 males, mean age 66.5 years (range 36–48 years). The initial diagnosis was osteoarthritis in 34 cases (76%), dysplasia in seven (16%), osteonecrosis in two (4%), Paget’s disease in one (2%) and rheumatoid disease in one (2%). The patients had had 2.8 dislocations on average (range 1 – 10). Time from first dislocation to the first-intention operation was 45.6 months (range 15 days – 20 years). Mean time from the first-intention operation to revision was 64.3 months (range 3 weeks – 20 years). Risk factors for instability were repeated hip surgery (> 3 operations) for 13 patients, wear for seven, nonunion of the greater trochanter for five, neurological and cognitive impairment in five, and malposition in three.

Results: Mean follow-up was 25.2 months. None of the patients were lost to follow-up. Two patients died late after the operation. Among the complications observed, there were: two cases of recurrent dislocation, one case of subluxation, two cases of infection (one with favorable outcome after surgical cleaning and antibiotics the other followed by patient death), two cases of deep vein thrombosis, one case of popliteal paresia with favorable outcome, one case of delirium tremens. Surveillance was the therapeutic option for the patient with subluxation. For patients with dislocation, revision surgery was performed using the same implant. For one of these patients, the dislocation occurred following early loosening.

Conclusion: Use of double-mobility implants for prosthetic revision undertaken because of prosthesis instability provides encouraging results, with a rate of dislocation (4%) close to that observed with first-intention implants.

Purpose: Acetabular revision has become a challenging situation due to the importance of bone stock loss encountered in SOFCOT stage III acetabula. The number of failures due to loosening are explained by the strong mechanical stress on the bone grafts or inadequate restitution of the rotation centre of the hip. The purpose of this study was to evaluate mid-term results of the Kerboull support used to achieve anatomic recentring of the hip and progressive weight bearing on the bone grafts.

Material and methods: This retrospective series included 54 acetabular revisions performed for stage III loosening between 1989 and 1996. A Kerboull support was used in all cases. The patients were assessed with the Postel Merle d’Aubigné score and radiographically on plain pelvis films in order to search for recurrent loosening or arthroplasty failure. The log rank test was used to compare actuarial survival.

Results: The series included 62% women. Mean age was 62.3 years (33–87). This was the first revision for 78% and a second or more revision for 22%. The preoperative Postel Merle d’Aubligné score was 9.18 points. This score was 12.3 postoperatively, 15.6 at one year, 15.5 at five years and 14.8 at last follow-up. Dislocation was the most frequent complication, with 55% occurring on cups more than 46° oblique. Grafts were considered radiographically integrated in 58% of the cases. There were 5.5% failures due to migration, 13.8% due to fracture of the superior screw. The actuarial survival was 97.4% at three years, 94.7% at four years, 89.2% at five years and 73% at seven and ten years.

Conclusion: On the basis of these good short-, mid- and long-term clinical and radiographic results, we recommend Kerboull support for the treatment of stage III acetabular loosening.

Purpose: Hip joint involvement is a frequent complication of Paget’s disease. We conducted a multicentric retrospective study to analyse perioperative problems and outcome after total hip arthroplasty in patients with Paget’s disease.

Material and methods: Thirty-nine total hip arthroplasties were implanted between 1979 and 1998 in 35 patients with Paget’s disease of the hip (four bilateral cases). The series included 20 men and 15 women, mean age 74 years (55–86). The pre and postoperative status was evaluated with the Harris score and radiographically. We recorded operative time, blood loss, and events noted in the operative report. Among the 35 patients, 24 were retained for analysis (three deaths, eight lost to follow-up) at mean 62 months.

Results: The mean preoperative Harris score was 46/100 (18–67). Eighteen patients had leg length discrepancy. Nine had permanent hip flexion associated with external rotation and seven had coxa vara. Twenty-nine patients were given anti-osteoclastic treatment preoperatively. We implanted 20 cemented cups and 19 press-fit cups. Thirty-one femoral stems were cemented and eight were not. On average, operative time was 130 minutes and blood loss was 830 cc. Difficult operative events involved luxation of the femoral head, remodelled sclerous bone (greater trochanter fractures, difficult reaming, narrow canal), cam effect related to bone hypertrophy and bleeding. Venous thrombosis occurred in four patients, pulmonary embolism in one, and one psoas haematoma. There were three luxations. At last follow-up (mean 71 months), the clinical outcome was excellent for 13 patients (48%), good for eight (29%), fair for two (7%) and poor for four (15%). Implants were cemented at the pelvis and femur level in three cases and noncemented in one.

Discussion: Prosthetic hip surgery in patients with Paget’s disease is difficult and raises the risk of postoperative complications. Prior medical treatment is needed before surgery to limit the risk of bleeding. In our series, fixation modalities were very variable. Non-cemented implants on Paget’s diseased bone performed comparably with non-cemented implants.

Purpose: Twenty-one total hip arthroplasties after ace-tabular fracture were reviewed at a minimum two-year follow-up. The purpose of this analysis was to study operative difficulties and complications in implanting a total hip arthroplasty on a sequelar acetabulum.

Material and methods: Ten acetabula had been treated surgically and eleven orthopaedically. Mean time interval between the initial trauma and the arthroplasty was 14 years (range 2 – 36). The posteriolateral approach was used in thirteen cases and the anterolateral approach in eight. Osteosynthesis material was totally removed in two patients and partially in three. Arthrolysis was performed in one patient who had grade IV heterotopic ossifications. Most of the cups were hydroxyapatite coated uncemented cups; two cups were cemented in a Postel Kerboul ring.

Results: An autologous graft was required for nine of the eleven orthopaedically treated fractures versus two of the ten surgically treated fractures (p < 0 .05). Mean operative time was 136 minutes and mean blood loss was 1200cc. Postoperative complications included one superficial phlebitis, one infraperitoneal bladder wound, one superficial haematoma, one incomplete popliteal palsy, one dislocation and two heterotopic ossiications (1 Brooker I and 1 Brooker IV). At review, the mean Postel Merle d’Aubigné score was 16.5. Radiologically there was no evidence of loosening or defective fixation.

Discussion: The operative difficulty was basically encountered in the group of orthopaedically treated acetabular fractures due to the callus (protrusion of the femroal head into the ovalised acetabulum. For these cases, an autologous graft was indispensable for reconstruction or defect filling (82% of the cases) to avoid excessive medialisation of the cup. For the fractures treated surgically, the osteo-synthesis material was only removed when it prevented proper cup position. An autologous graft was used to fill defects (18%) (wall or roof necrosis). Cup insertion without cement is the rule for first-intention treatment in these young patients, the supporting ring being used when required for second-intention treatment.