Modular Femoral Stem Research Articles

Caveat Emptor: Adverse Inflammatory Soft-Tissue Reactions in Total Hip Arthroplasty with Modular Femoral Neck Implants

Modular femoral neck (MFN) implants in total hip arthroplasty facilitate optimizing femoral offset and version while minimizing femoroacetabular impingement1, but component fracture and dissociation have been reported with titanium-alloy MFN implants2-6. Cobalt-chromium MFN components have improved strength compared with earlier designs, but the long-term consequences of wear and corrosion at the femoral neck-stem junction are unknown3,7. Inflammatory metal-hypersensitivity reactions have been most frequently reported in cobalt-chromium metal-on-metal articulations used in total hip arthroplasty and hip resurfacing arthroplasty8,9, but to our knowledge, these reactions have not been described in MFN implants with metal-on-polyethylene articulations. We present two patients with MFN implants who developed partially cystic peri-implant soft-tissue masses with histologic features suggestive of metal hypersensitivity requiring revision arthroplasty. Both patients were informed that data concerning their cases would be submitted for publication, and they provided consent. Case 1. A sixty-three-year-old woman (body mass index, 31.3) with severe osteoarthritis had undergone a left total hip arthroplasty with a 50-mm Trilogy Shell (Zimmer, Warsaw, Indiana), a 36-mm highly crosslinked polyethylene liner (Zimmer), an uncemented titanium-alloy ABG II size-3 modular femoral stem with a 130° cobalt-chromium MFN (Stryker, Mahwah, New Jersey), and a +5-mm 36-mm cobalt-chromium head (Stryker). The patient had an uneventful postoperative course and was discharged on postoperative day three. Seven months later, the patient presented with progressive pain in the left hip. Radiographs showed satisfactory component positioning with no osteolysis, aseptic loosening, or periprosthetic fracture. Blood work showed an elevated erythrocyte sedimentation rate (ESR), C-reactive protein level (CRP), and serum metal ion levels without leukocytosis (Table I). Computed tomography (CT) of the hip demonstrated a 2.3 × 3-cm fluid collection between the gluteus maximus and medius muscles. Aspiration of the hip yielded 2 mL of orange-tainted …

Medium-Term Outcome in Patients Treated with Total Hip Arthroplasty Using a Modular Femoral Stem

The clinical, radiographic and quality of life results of total hip arthroplasty using the MODULUS cementless modular femoral stem were reviewed. 48 patients who had a total hip arthroplasty using the MODULUS femoral stem were identified. Six had bilateral procedures, resulting in 60 hips with complete clinical and radiographic data. Mean age at implantation was 50 years (range 33 to 82). Mean follow-up was 59 months (range 50 months to 73). There were two early post-operative dislocations (within 2 days). One patient required further surgery to remove heterotopic bone. Mean Harris Hip Score increased from 37 points preoperatively (range, 7 to 66) to 89 points at final review (range, 65 to 100 points). Radiographic evaluation revealed that all implants were stable without evidence of osteolysis but three patients (5%) exhibited heterotopic ossification. Quality of life was evaluated with the SF36. The physical component increased from 29.2 points (range, 18.5 to 46.0) to 51.7 points (range 42.9 to 60.6) and the mental component from 375 points (range, 19.5 to 50.0) to 50 points (range 32,8 to 62.0).

Cementless Total Hip Arthroplasty Using a Modular Femoral Component in Patients with Femoral Head Osteonecrosis: Comparison of Metal-on-Metal and Ceramic-on-Ceramic Articulation

� Purpose: The purpose of this study was to evaluate the clinical and radiological outcomes after total hip arthroplasty using the S-ROM modular system for osteonecrosis of the femoral head, and to compare the results between the groups using metal-on-metal articulation and ceramic-on-ceramic articulation. Materials and Methods: Sixty-six patients (78 hips) with osteonecrosis of the femoral head were evaluated after primary total hip arthroplasty between January 2001 and December 2004, using an S-ROM proximal modular femoral stem. The average follow-up was 77 months (range, 60 to 122 months) and all patients were followed for more than five years. Results: The average Harris hip score improved from 53 points to 88.5 points at the final follow-up. At the latest radiologic evaluation, sixty-seven stems had bony ingrowth stability, and 10 stems had stable fibrous ingrowth. However, one stem had diffuse extensive osteolysis and loosening, which was revised at 9 years. Postoperative complications included 4 cases of heterotrophic ossificiation, 1 case of linear fracture after insertion of the femoral stem, 1 case of dislocation, 2 cases of infection, and 1 case of extensive osteolysis and loosening. There were 3 cases of revision and Kaplan-Meier survivorship analysis with revision estimated at a 95.7% chance of survival for the femoral component during 122 months. Conclusion: Our study showed that total hip arthroplasty using the S-ROM modular system with metal-on-metal articulation or ceramic-on-ceramic articulation had favorable clinical and radiological mid- to long-term results.

Management of Vancouver B2 and B3 femoral periprosthetic fractures using a modular cementless stem without allografting.

We reviewed our experience with the management of B2 and B3 femoral periprosthetic fractures using a distally fixed modular femoral stem in 55 patients. All periprosthetic fractures were managed immediately after injury without using allograft; 53 hips were available for a mean follow up of 67 months. All fractures united, and the mean Harris hip score at the last follow up was 72. Subsidence was noted in two patients (4%) within six months postoperatively and required revision surgery. One patient developed peroneal nerve palsy. Two hips dislocated and were managed by closed reduction. In these severe cases of periprosthetic fracture, the technique reviewed here proved to be reliable.

Repeatable procedure for evaluating taper damage on femoral stems with modular necks

Understanding the performance of dual-taper modular femoral stems necessitates detailed quantitative assessment. This study reports a repeatable procedure to identify and measure damage on modular taper surfaces and determines whether damage area is a useful parameter for discerning modular femoral stem performance during in vitro corrosion and endurance tests. Twenty-four dual-taper modular necks representing a range of functional conditions were evaluated, including 15 necks previously subjected to in vitro testing and 9 necks explanted during revision hip arthroplasty. Objective identification of six surface features, including four unique damage modes, was accomplished using defined criteria combined with a standardized photogrammetric method for accurate and repeatable measurement of damage area and location. Damage area was a useful parameter for discerning the performance of modular femoral stems subjected to different in vitro tests. The sum of burnished smooth and textured damage areas was linearly correlated with the magnitude of material removed (weight loss) during in vitro testing, predicting ∼ 1.0 mg additional weight loss for every 10% increase in those combined damage areas. Modular necks tested with higher load magnitudes and those coupled with larger, stiffer femoral stems were readily distinguished and showed significantly larger areas of burnished smooth and textured damage.

Primary total hip arthroplasty with dual mobility socket to prevent dislocation: a 22-year follow-up of 240 hips

The longest follow-up dual mobility series from inventor Gilles Bousquet focussing on implant survival and the incidence of dislocation. This was a retrospective study from 1985 to 1990, on 240 hips using a PF® modular femoral stem and a dual mobility Novae® tripodal socket (SERF). The 22-year follow-up global survival rate was 74%. No dislocation occurred, 41 hips were revised, including ten retentive failures (RF), 12 hips were lost to follow-up, 87 patients (99 hips) died without revision, and 90 hips were still in situ. The dual mobility socket global survival rate is comparable to similar series. The 0% dislocation rate demonstrates the success of dual mobility with regard to implant stability. The main issues were cup fixation, which might be improved by the use of macrostructures and HA coating, and osteolytic lesions, caused by polyethylene wear. Traditionally suitable for patients older than 60 years, dual mobility might be extended for use in patients over 50.

Outcome After Femoral Revision Using the Restoration Cone/conical Femoral Revision Stem

Despite improvements in implant technology and surgical technique, failure of total hip arthroplasty (THA) remains a persistent problem. This article reports clinical outcomes at a mean follow-up of 42 months using the Restoration cone/conical modular femoral revision stem (Stryker, Newbury, United Kingdom). A prospective cohort study was performed of 46 consecutive patients who underwent revision THA between January 2004 and June 2007. Patients were reviewed pre- and postoperatively at regular intervals for clinical and radiological assessment. Forty-six patients (17 men, 29 women) with a mean age of 72 years (range, 44-93 years) were observed for a mean of 42 months (range, 28-66 months). Indications for surgery included aseptic loosening/osteolysis (38/46 [83%]), periprosthetic fracture (4/46 [9%]), and infection (4/46 [8%]). Median time from index procedure was 16 years (range, 1-26 years). No patient was lost to follow-up. Two patients (4%) with well-fixed asymptomatic stems died during follow-up. Three patients (7%) sustained an early postoperative dislocation. One patient sustained a periprosthetic fracture after a fall. This was treated by osteosynthesis, and stem revision was not required. Mean Oxford Hip Score improved from 42 points (range, 24-57 points) to 28 points (range, 18-51 points) at 3-month follow-up (P=.003). Median stem subsidence was 1.0 mm (standard error of the mean, ±1.7 mm; range, 0-7mm) at last follow-up. No patient developed loosening or osteolysis around the stem. The Restoration femoral revision system has favorable clinical and radiological outcomes at a mean follow-up of 42 months.

Revision hip arthroplasties with use of the modular s-rom prosthesis

The aim of this study was to revision hip arthroplasties in ankylosing spondylitis. We performed 21 revision hip arthroplasty in 16 patients with ankylosing spondylitis (AS) using S-ROM modular femoral stem. At the final follow-up, all patients were able to ambulate without any walking aids. The mean Harris hip score improved from 57.2 (35 to 74) pre-operatively to 90.2 points (73 to 100) post-operatively, and the outcome was classified as good or excellent in 17 hips (81%). Fixation of the femoral component was classified as stable with bone ingrowth in 15 hips (71.4%), stable with fibrous ingrowth in 2 hips (9.5%), and radiolucent loosening in 4 hips (19.1%). Five hips developed a pedestal at the tip of femoral component. Femoral osteolysis was found in 3 hips (14.2%): 3 hips in Gruen zones 1 and 7, one hip in zone 7, and two hips in zone 1. One hip underwent acetabular revision because of breakage of polyethylene liner, and the well-fixed femoral component was left in situ. Thigh pain developed in 1 patient (6.2%). Kaplan-Meier survival was 81% at 64 months, with radiographic loosening as an end-point when two hips were at risk. Satisfactory results of midterm clinical and radiographic follow-up can be achieved using S-ROM modular femoral stem for revision of femoral stem in ankylosing spondylitis.

Total Hip Arthroplasty Using S-ROM Prosthesis for Dysplastic Hip

PurposeThe purpose of this study was to evaluate the clinical and radiological results of total hip arthroplasty using a proximal modular femoral stem in patients who had secondary coxarthrosis associated with a dysplastic hip.Materials and MethodsForty-two patients (45 hips) with secondary coxarthrosis were evaluated after undergoing primary total hip arthroplasty using an S-ROM proximal modular femoral stem. The average follow-up was 80 months (range: 60 to 96 months). Clinical and radiological assessments were performed based on the Harris hip score and the radiological changes around the prosthesis.ResultsThe average Harris hip score improved from 52.2 points to 88.5 points. All femoral stems showed stable fixation; there were 37 cases by bony ingrowth and 8 cases by stable fibrous ingrowth. Neither osteolysis nor progressive radiolucent lines around the femoral stem were found at the last follow-up. Forty-one hips (91.9%) revealed excellent or good clinical results at the most recent follow-up.ConclusionFor advanced secondary coxarthrosis, total hip arthroplasty with the use of the proximal modular femoral stem yielded good mid-term results with respect to the clinical and radiological criteria.

Modular Femoral Stems for Revision Total Hip Arthroplasty

Modular femoral stems are one option for revision THA surgeons and allow offset restoration, leg length discrepancy correction, and stability independent of distal stem fixation. The complexity of revision THA usually leads surgeons to use multiple revision hip designs to address these issues. We evaluated functional outcomes with a revision modular system and determined whether such a system achieved initial distal fixation, femoral offset restoration, leg length equalization, and hip stability. We prospectively followed 118 patients in whom a modular stem system was used for reconstruction of their failed index femoral stem. Sixty-nine hips were classified as Type I (classification of Paprosky et al.), 35 as Type II, 17 as Type III, and one as Type IV. Functional assessment was achieved using patient- and physician-administered outcome evaluations (SF-36, WOMAC, Lower Extremity Activity Scale, Harris hip score). Stem fixation, offset restoration, leg length discrepancy, and hip stability were evaluated radiographically. Complications were also recorded. Minimum followup was 2 years (average, 4 years; range, 2-7 years). Average values on all functional outcome evaluations showed improvement at latest followup. Distal bone ingrowth fixation was obtained in 100% of the patients, offset was corrected in 66%, leg length discrepancy was corrected in 78%, and stability was achieved in 97%. No failures or fractures at the body to stem junction were seen at latest followup. Modular femoral components achieved functional outcomes and were useful to address distal fixation, femoral offset restoration, leg length equalization, and hip stability when revising failed femoral components. Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Modular Femoral Sleeve and Stem Implant Provides Long-term Total Hip Survivorship

A femoral implant with a modular sleeve and stem has been designed to allow independent and complete metaphyseal-diaphyseal fit and fill as well as independent rotation to accommodate anteversion at the time of THA. In a prospective study we asked whether such a modular femoral sleeve and stem implant used during THA could provide (1) high long-term survivorship; (2) radiographically stable implants without radiolucencies, stress shielding, or osteolysis; and (3) high clinical scores in patients 15 to 20 years after a primary THA. We prospectively evaluated 31 hips that underwent a primary THA using a modular femoral component for clinical outcome (Harris hip score) and radiographic outcome (implant stability, femoral loosening, osteolysis and stress shielding) at a minimum followup of 15 years (mean, 17 years; range, 15-20.2 years). There were no femoral revisions for aseptic loosening; all hips had radiographic evidence of bone ingrowth. Two well-ingrown components were revised for late hematogenous infection. Some degree of proximal femoral disuse atrophy from stress shielding occurred in 23 hips (74%) but was nonprogressive and did not result in any failures or complications. Femoral osteolysis occurred in 18 hips (58%), but we cannot definitively determine whether or not the modular junction contributed to this. These data suggest this modular femoral stem can provide long-term survivorship with no cases of aseptic loosening at 15 to 20 years after primary THA. However, it may be prudent when using this femoral stem to consider an articulation with an alternative bearing or, if the modularity is not needed to address femoral anteversion and metaphyseal-diaphyseal mismatch, to consider a nonmodular femoral stem. Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Periprosthetic Stress Fractures at the Sleeve/Stem Junction of the Sivash-Range of Motion Modular Femoral Stem

We report on 13 cases of periprosthetic stress fracture at the sleeve/stem junction using the Sivash-Range of Motion femoral prosthesis. Radioisotope bone scans confirmed the incidence of fracture, and review of the lateral radiographs revealed anteromedial notching of the distal sleeve on the metaphyseal throat of the femur. Treatment in all cases was expectant with full resolution of symptoms. However, there were 3 cases of recurrence, 1 of which needed revision to a more distally loading stem. This is a rare complication when using this prosthesis, but we recommend a slight alteration of the entry point for the femoral reamer when using this stem and advise nonsurgical management if it occurs, as the natural history is for the condition to settle.

Management of Periprosthetic Femur Fractures Treated With Distal Fixation Using a Modular Femoral Stem Using an Anterolateral Approach

The authors retrospectively analyzed 27 hips with periprosthetic femoral fractures (types B2 and B3) treated with distal fixation using a modular, fluted, femoral stem. The average follow-up was 4.8 years. Most fractures (25 hips) were united (92.6%), and mean Harris Hip Score at follow-up was 84.7. Subsidence was noted in 2 patients within 6 months postoperatively, but despite the subsidence, one achieved union. One patient developed peroneal nerve palsy. Two hips were defined as failure: one nonunion associated with infection, and the other one had 10 mm more subsidence. No dislocation occurred in any of the patients. This technique has proven to be reliable in the treatment of difficult fractures in the acute stage, although concerns regarding the subsidence remain when using this femoral stem.

Detection of Locking Bolt Loosening in the Stem-Condyle Junction of a Modular Femoral Stem in Revision Total Knee Arthroplasty

We report one case of loosening of the locking bolt in the stem-condyle junction of a constrained modular femoral component in revision total knee arthroplasty. Early detection of loosening of the locking bolt was possible using reconstructed view of computerized tomography scans before complete disengagement and radiographic loosening of the stemmed femoral component. When using the Total Condyle III femoral component with a stem extension, surgeons should keep in mind that stress concentration at the stem-condyle junction can result in failure of the locking bolt although it is rare and that loosening or disengagement of the locking bolt may be a sign of a loose stemmed femoral component.

A report of salvage treatment for infected bipolar hip arthroplasty and dislocation of bipolar hip arthroplasty using modular femoral stem

A report of salvage treatment for infected bipolar hip arthroplasty and dislocation of bipolar hip arthroplasty using modular femoral stem

Results of a Hydroxyapatite-Coated Modular Femoral Stem in Primary Total Hip Arthroplasty. A Minimum 5-Year Follow-Up

The use of a modular metaphyseal-diaphyseal femoral stem in primary total hip arthroplasty is infrequent. We analyze 94 ESOP (Fournitures Hospitalieres, Heimsbrunn, France) cementless 2-piece modular stems after a minimum 5 years of follow-up. There were 2 aseptic femoral stem loosenings and no cases with thigh pain. Mean femoral canal filling was 90%. Radiographic ingrowth was obtained in 83 ( P < .001). At 7 years, the survival rate for femoral aseptic loosening was 97.8% and no stem was at risk for revision (95% confidence interval, 94.8%-100%). This prosthesis provides good clinical results with absence of pain and excellent radiographic results. It is an option in femora with good bone quality. Femoral osteopenia and cortical widening were infrequent, and the modular metaphyseal-diaphyseal junction was not a problem in vivo.

Dislocation Rate After Conversion from Hip Hemiarthroplasty to Total Hip Arthroplasty

Revision hip arthroplasty is associated with a dislocation rate that is three to five times greater than the rate following primary hip replacement. Conversion of a hip hemiarthroplasty to a total hip replacement is a revision arthroplasty, but it differs from revisions of total hip arthroplasties because a native acetabulum is replaced and the subsequent prosthetic femoral head is smaller. It was our purpose to determine whether the risk of dislocation following conversion surgery is the same as or greater than that following revision total hip replacement. From 1994 to 2005, eighty-nine hemiarthroplasties were converted to a total hip arthroplasty in seventy-seven patients, and the results were compared with those of 115 first-time revision total hip replacements following a primary total hip replacement in 111 patients. A retrospective chart review was performed, and radiographic measurements were obtained. The patient demographics were similar between the two groups. The percentages of patients who had undergone revision of only the acetabular component as compared with both components as well as the percentages of those who had received a modular femoral stem as compared with a nonmodular stem were also similar between the two groups. Postoperatively, the femoral head size and the positioning of the acetabular component were similar between the two groups. The acetabular components were significantly larger (p < 0.001) in the group in which a total hip arthroplasty had been revised because they required additional acetabular reaming for placement of a new component. There were significantly more dislocations after the conversion procedures (22%) than after the revisions of the total hip arthroplasties (10%) (p < 0.018). Within both groups, the size of the acetabular component, the intraoperative range of motion, and the positioning of the acetabular component were similar between the hips that dislocated and those that did not. However, smaller femoral head components were at greater risk for dislocation after conversion surgery than after revision of a total hip arthroplasty. A substantial reduction of the size of the prosthetic femoral head is unique to conversion arthroplasty and appears to play a role in instability after the revision surgery. While the smallest heads dislocated in the conversion group, a larger femoral head did not ensure stability. The increased dislocation risk with conversion surgery requires emphasis on soft-tissue balance and avoidance of excessive downsizing of the femoral head in an attempt to maximize hip stability.

Hip Arthroplasty Using Cementless Modular Femoral Stem for Displaced Femoral Neck Fracture in Patients More than 70 Years Old

Hip Arthroplasty Using Cementless Modular Femoral Stem for Displaced Femoral Neck Fracture in Patients More than 70 Years Old

Modular Femoral Head Dissociation after Dislocation and Entrapment in Reconstruction Ring: A Case Report

Dissociation of modular components is an infrequent potential complication characteristically unique to modularity. We present a patient in whom dissociation of the modular femoral head occurred at attempted closed reduction after dislocation, with the intraoperative findings including entrapment of the head between the rim of a reconstruction ring and the acetabular bone. In the case a dislocation in a patient that was previously reconstructed with a reinforcement ring and a modular femoral stem occurs, dissociation of the modular head should be considered as an extremely uncommon complication that does not outweigh the advantages given by modularity.

Modular femoral head dissociation after dislocation and entrapment in reconstruction ring: a case report

Dissociation of modular components is an infrequent potential complication characteristically unique to modularity. We present a patient in whom dissociation of the modular femoral head occurred at attempted closed reduction after dislocation, with the intraoperative findings including entrapment of the head between the rim of a reconstruction ring and the acetabular bone. In the case a dislocation in a patient that was previously reconstructed with a reinforcement ring and a modular femoral stem occurs, dissociation of the modular head should be considered as an extremely uncommon complication that does not outweigh the advantages given by modularity.