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

Recurrent instability after total hip arthroplasty remains a serious and somewhat frequent problem. Constrained implants have proven effective to manage instability. This has led to a liberal utilization of these devices. However, sporadic mechanical failures have been reported. This report analyzes the failures of a single constrained device at our institution.

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: Data are scarce in the literature on lower limb length discrepancy (LLD) after total hip arthroplasty (THA). This parameter is difficult to evaluated intraoperatively with conventional instruments. In addition LLD after THA is often poorly tolerated and can be a source of legal suites. The purpose of this work was to evaluate the contribution of navigation for controlling lower limb length during implantation of a THA.

Material and method: Sixty-five THA were implanted in 63 patients, aged 35–81 years, using a passive navigation system based on a function reference system which controlled the position of the implants and the length of the operated leg. Limb length and femur length were measured radiographically on both sides before and after surgery. The horizontality of the acetabular U lines was measured on the AP view of the pelvis. An independent radiologist made all measurements.

Results: The precision of the radiographic measurements was < 3 mm. The precision of the navigation system was < 3 mm. Subjectively, 56 of the 63 patients did not have a feeling of LLD preoperatively. No un programmed difference > 3 mm in leg length between the before and after THA measurements was noted. Preoperatively, seven patients complained of lower back pain related to LLD and three had a compensated shoe measuring 5 to 10 mm. These latter three patients had a horizontal pelvis (< 1) after THA. In all cases, the overall length correction was achieved by adapting the length of the neck.

Discussion: In our opinion, not all radiologically determined and/or clinically perceived LLD should be corrected. Care must be taken to ensure that permanent preoperative hip flexion does not perturb limb length measurements.

Conclusion: The navigation system used in this series for the implantation of THA was able to control operated limb length with precision.

Purpose of the study: In rheumatoid arthritis, 15 to 28% of patients present hip involvement, sometimes requiring arthroplasty. The purpose of this work was to evaluate the usefulness of cementless implants for patients with inflammatory hip disease, recognising that cemented implants are widely used for this indication.

Material and method: The was a retrospective series of 63 consecutive first-intention cementless total hip arthroplasties (THA) implanted from April 1986 to June 2007 in 48 patients (35 females), mean age 55 years (range 19–87), with rheumatoid arthritis. The majority of these patients were on a two-drug regimen of corticosteroids and methotrexate. Twelve patients were taking anti-TNF alpha. In all cases, both the femoral and acetabular elements of the implant were inserted without cement. The Postel-Merle-d’Aubligné (PMA) score was used for clinical assessment (preop, postop, last follow-up). Signs of loosening were noted on the plain x-rays.

Results: Mean follow-up was 103 months (range 12–264). There was a significant improvement in the PMA score. There were two intraoperative complications (calcar fissuration). Twenty-one cases (33%) exhibited acetabular protrusion requiring autologous bone graft. At last follow-up, all acetabular grafts were incorporated. At last follow-up there were no cases of deep infection. Three cases (4.8%) required uniplar acetabular revision for aseptic loosening at 127, 145, and 217 months after initial implantation. Major wear of the polyethylene insert was observed in all hips, associated with retroacetabular osteolysis. A new cementless implant was used for the revision in two cases, with satisfactory outcome a mean 41 months from revision. In addition, four cups and three stems presented unchanged lucent lines and had not been revised at last follow-up.

Discussion: THA is a therapeutic option for the rheumatoid hip. Long-term outcome with cemented THA has shown an increased incidence of deep infections and aseptic loosening in this context. At mean 9 years follow-up, we have had very encouraging results with cementless implants in this context.

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 of the study: The rate of intra and postoperative complications is generally high after surgery for neurogenic paraosteoarthropathy, also termed hetero-topic ossification.

Material and methods: We present a series of 60 cases of osteoma involving the hip joint, analyzing complications in comparison with data in the literature.

Results and discussion: Vascular complications (n=7): one required suture of the common femoral artery, three ligature of the deep femoral artery, two ligature of the deep femoral vein and one ligature of the collateral branches of the deep femoral vessels. Mean intraoperative blood loss was 1300 cc. None of the vascular complications gave rise to death or amputation. Early septic complications (n=4): three occurred after simple resection of the ossification and cured after surgical revision and antibiotics with no major impact on joint motion; one occurred after a procedure for resection of the ossification plus total hip arthroplasty and led to ankylosis of the hip joint but cured after surgical revision and prolonged antibiotic therapy. Sepsis was favored by a long hemorrhagic surgical procedure in patients at risk. Neurological complications (n=0): such complications are greatly feared but rare. Posterior ossifications expose the sciatic nerve to injury but generally displacement the nerve rather than enclosing it in the osteoma. Fracture complications (n=1): the outcome was favorable, both in terms of bone healing and joint motion. A classical complication mentioned in the literature and synonym to recurrent ossification or invalidating residual stiffness. Most are favored by ankylosis, osteoporosis, immobilization and a particularly dynamic surgeon. Recurrences (n=6): all were posttraumatic with a delay from accident to surgery ≥ 18 months.

Conclusion: Complications are related to the localization of the osteoma (relations with nerves and vessels), associated osteopathy, and the complete or partial joint stiffness. Preoperative imaging (x-rays and computed tomography with contrast injection) should localize the osteoma, keeping in mind that certain localizations create preferential conditions for certain risks. An analysis of the topography of the paraosteoarthropathy should enable the surgeon to choose the most appropriate approach. Intraoperatively, risk assessment can usefully anticipate complications which always compromise functional outcome.

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.