Primary total hip arthroplasty using a grit-blasted, press-fit femoral prosthesis.Long-term results with survivorship analysis

The Wagner Cone Stem for Atypical Femoral Anatomy in Total Hip Arthroplasty: A Report of 320 Cases with Minimum 5-Year Follow-up

BACKGROUND

The Wagner Cone Prosthesis was designed to address complex femoral deformities during total hip arthroplasty (THA), but its mid-term component survivorship and functional outcomes remain undetermined. The objectives of this study were to determine the implant survivorship, patient satisfaction, functional outcomes, osseointegration as seen radiographically, implant subsidence, and complications of THA using the Wagner Cone Prosthesis stem at intermediate-term follow-up.

METHODS

This study involved 302 patients with proximal femoral deformities, including developmental hip dysplasia and Legg-Calvé-Perthes disease, who underwent a total of 320 primary THAs using the Wagner Cone Prosthesis. The average age at the time of surgery was 49.4 ± 14.5 years (range, 18.8 to 85.6 years). Patient satisfaction was recorded using a self-administered questionnaire assessing satisfaction in 4 domains. The University of California at Los Angeles (UCLA) activity score, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Oxford Hip Score (OHS), the Forgotten Joint Score (FJS), radiographic outcomes, and complications were recorded. The mean follow-up time was 10.1 years (range, 5.2 to 15.5 years).

RESULTS

Survivorship of the Wagner Cone Prosthesis was 98.7% (95% confidence interval [CI]: 97.2% to 100%) with stem revision as the end point and 95.8% (95% CI: 93.5% to 98.2%) with reoperation for any reason as the end point at 10 years postoperatively. In total, 3 stems were revised: 2 for infection and 1 for chronic hip dislocation. The median patient satisfaction score was 95 (interquartile range [IQR], 80 to 100), median UCLA score was 6 (IQR, 6 to 7), median WOMAC score was 18 (IQR, 16 to 22), median OHS was 40 (IQR, 36 to 47), and median FJS was 80 (IQR, 76 to 88) at the time of final follow-up. All Wagner Cone stems that were not revised showed radiographic evidence of osseointegration, with a mean stem subsidence of 0.9 ± 0.8 mm at the most recent follow-up.

CONCLUSIONS

The use of the Wagner Cone Prosthesis stem in patients with complex femoral anatomy undergoing primary THA is associated with excellent component survivorship, high levels of patient satisfaction, good functional outcomes, and reliable osseointegration with minimal stem subsidence as seen on radiographs at intermediate-term follow-up.

LEVEL OF EVIDENCE

Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Excellent Results of Large-Diameter Ceramic-On-Ceramic Bearings in Total Hip Arthroplasty at Minimum Ten-Year Follow-Up

BACKGROUND

This study reports the minimum 10 years results of total hip arthroplasty (THA) performed using a monoblock acetabular component with a large-diameter head ceramic-on-ceramic bearing.

METHODS

Of the 276 THAs included in this study, there were eleven deaths and 27 patients lost to follow up (11%) during the follow-up, leaving 237 (85%) hips available for review at a mean of 10.5 years (range, 10 to 12) postoperatively. Reoperations, implant revisions, adverse events, clinical outcomes, radiographic evaluation, and whole blood metal ion levels were assessed at the last follow-up.

RESULTS

After a minimum of 10 years, implant survivorship was 98.7%. There were 3 revisions (1.3%): one for insufficient acetabular cup primary fixation, one traumatic periprosthetic acetabular fracture, and one probable deep chronic infection. No dislocation or ceramic implant fracture was observed. The mean University of California at Los Angeles activity score, Western Ontario and McMaster Universities Osteoarthritis Index score, and Forgotten Joint Score were 5.6 (2 to 10), 90.1 (9 to 100), and 79.2 (4 to 100), respectively. All patients (100%) were satisfied or very satisfied. Since implantation, 43% of patients reported hearing a squeaking noise from the prosthesis. But all patients who reported squeaking were satisfied with the surgery. The mean titanium level was 2.2 μg/L (1.1 to 5.6). No progressive radiolucent lines, osteolysis, or implant loosening signs were observed at the last radiographic evaluation.

CONCLUSIONS

A large-diameter head ceramic-on-ceramic THA provides outstanding long-term (minimum 10 years) implant survivorship with unrestricted activity while avoiding implant impingement, liner fracture, and hip instability. Functional outcomes, satisfaction, and joint perception were excellent. Although the incidence of squeaking was high, it did not affect patient satisfaction or function. The systemic titanium levels were low, related to unavoidable passive corrosion of implant surfaces, and did not reveal any indirect signs of trunnionosis.

Mid-Term Migration Behavior of an Uncemented Proximally Anchored Straight Stem-A Retrospective EBRA Migration Analysis

BACKGROUND

Aseptic loosening is one of the most-common causes of the failure of cementless stems. Einzel Bild Röntgen Analyse-Femoral Component Analysis (EBRA-FCA) allows the diagnosis of stem migration, which can be considered a factor in predicting implant survival. The current study aimed to present the migration behavior of a tapered proximally anchored straight stem.

METHODS

This retrospective study reviewed all consecutive patients who received a cementless CBC straight stem (Mathys AG, Bettlach, Switzerland) between 2005 and 2019. We analyzed the migration pattern using the EBRA-FCA software and reviewed their medical histories. In addition, periprosthetic radiolucency was rated according to the Gruen zones and femoral configuration according to Dorr.

RESULTS

A total of 333 stems in 332 patients (female 191; male 141) met our inclusion criteria. The mean age at surgery was 63 (range 21-87) years. Migration analysis by EBRA-FCA showed a mean subsidence of 1.6 mm at final follow-up at 96 months with a maximum noted mean subsidence of 2.0 mm at 72 and 84 months. Dorr Type A showed a tendency of less subsidence than did Dorr Type B and was statistically significant at 6 (p = 0.0396) and 72 months (p = 0.0127). The body mass index (BMI) and increased subsidence were not found to correlate (p > 0.05). For this cohort, the overall femoral revision-free rate was 95.2% and the revision-free rate for aseptic loosening was 99.1%.

CONCLUSIONS

The results showed migration behavior in cementless stems with initial increased migration and subsequent secondary stabilization, suggesting an excellent long-term outcome. Stem migration of this tapered proximally anchored stem might be lower in Dorr Type A than in Dorr Type B femurs without being statistically significant at all time points.

Midterm results of titanium conical Wagner stem with challenging femoral anatomy: Survivorship and unique bone remodeling

BACKGROUND

Complex anatomy of the proximal femur makes total hip arthroplasty (THA) more challenging. Short, straight, fluted and conical titanium stem like the Wagner Cone can be helpful to address small femoral canal, increased femoral neck version, important leg length discrepancy or proximal femoral deformity. The outcome in these patients is less assured and associated with high rate of complications. Therefore, we did a retrospective study aiming to answer: 1) can the Wagner Cone stem provide acceptable mid- to long-term implant survivorship; 2) help minimizing perioperative adverse events; 3) produce favorable clinical outcome measured by WOMAC score; and 4) be associated with a favorable radiographic femoral bone remodeling at the last follow-up?

HYPOTHESIS

Wagner Cone stem is an advantageous solution for the distorted proximal femur in complex THA.

PATIENTS AND METHOD

Our cohort was derived from the patient registries where medical records of 88 patients (103 hips) who underwent primary THA using the Wagner prosthesis were retrospectively reviewed. Then, data was analyzed for patients' demographics and surgical data, and comparing preoperative, immediate postoperative and last follow-up data. Eleven patients (12 hips) were excluded (7 hips followed up less than 2 years or lost to follow-up, 3 hips that had the Wagner stem for revision and 2 Wagner stems inserted for periprosthetic fracture). This left 77 patients (91 hips) with Wagner cone stems implanted for more than 2 years between March 2003 and February 2017 by 7 surgeons in 3 academic hospitals. Implant revision, reoperations, WOMAC score and radiographic analyses were recorded at last follow-up.

RESULTS

After a mean follow-up of 7.8 (range, 2.0-16.2) years, Wagner stem survivorship was 98.9% (95% CI: 94 to 100%) with one (1.1%) stem revision for failure of osteointegration. Five (5.5%) acetabular revisions, one for aseptic loosening, 2 for adverse reaction to metal debris and 2 for infection. One (1.1%) sciatic neuropathy and 4 (4.4%) intraoperative fractures were encountered. The mean WOMAC score was 90.5±11.4 (59-100). Radiographic analysis showed clear signs of stem osseointegration and hypertrophic bone remodeling in 82 cases (92.1%).

CONCLUSIONS

Used in complex cases with proximal distorted femurs, the Wagner Cone stem demonstrated a low complication rate, a high-rate consistent adaptive bone remodeling, excellent clinical results, and midterm survival. It is a safe, reliable and advantageous option in complex primary THA. However, the contribution of the underlying cause of the secondary osteoarthritis on the long-term survival of the stem remains to be demonstrated.

LEVEL OF EVIDENCE

IV; retrospective study.

Long-term survival of CLS Spotorno femoral stem: a systematic review of literature

BACKGROUND

CLS Spotorno is a time-tested femoral stem design with excellent early results; the present review was designed to assess the published evidence on CLS Spotorno stem in the literature to evaluate its long-term outcomes and compare it to two other popular stem designs the uncemented Corail™ and the cemented Exeter™ stems.

RESEARCH QUESTION

Do CLS Spotorno stems provide adequate long-term rates of survival in terms of revisions and functional outcomes?

METHODOLOGY

Medline, EMBASE and SCOPUS databases were searched for relevant articles and a total number of 670 hits were obtained, out of which 14 relevant studies were included in this review. Pooled analysis of revisions rates, subsidence and Harris Hip scores (HHS) were done.

RESULTS

All the 14 studies were retrospective in design but had sufficiently large follow-up periods (12.3-27 years, mean 17.1 years). Of the 2459 hips reviewed, the documented revision rate was only 6.2%, with aseptic loosening reported in 3.1% and subsidence > 2 mm in 2.6% cases. The overall survival was similar to reported smaller cohorts of Corail (95% at 12 years) and Exeter stems (100% at 17 years). Varus malposition was seen in 10.6% cases, but it did not show any influence on implant survival or revision rates. Distal pedestal formation was seen in 172 of 805 hips across seven studies, while distal cortical hypertrophy was seen in 70 cases out of 398 hips; these were not related with stem malposition. The overall functional outcome was good, with mean HHS of 88.65 (95% CI = 86.08-91.23, p < 0.01). The improvement in scores from preoperative values (of 43.9 points) were comparable to Corail (43.8) and Exeter (45) stems. Thigh pain was seen in only 41 cases out of 1097 hips.

CONCLUSION

Despite the limitations due to high heterogeneity of the cumulative data, the review suggests that CLS Spotorno femoral stems provides excellent long-term survival and good hip function. These outcomes are comparable to other commonly utilized femoral stems like the Corail and Exeter.

LEVEL OF EVIDENCE

IV.

Comparison of short-stem versus conventional stem for hip arthroplasty in patients younger than 60 years: 7-14 years follow-up

PURPOSE

Short-stem prostheses in hip arthroplasty have emerged as an alternative to conventional stems, especially in younger patients. The purpose of this study was to compare functional and radiological results of a short metaphyseal fitting cementless stem versus a conventional stem implant, in patients younger than 60 years.

METHODS

All patients operated from January 2006 to April 2013 were included, obtaining a minimum follow-up of 7 years. Harris Hip Score (HHS) and SF-36 (quality of life) questionnaires were applied and the presence of "thigh pain" was specifically assessed. We also compared complication rate, revision rate and average prosthesis survival. Femoral stress shielding (Gruen scale), stem subsidence, varus-valgus tilt and implant stability (Engh scale) were also compared.

RESULTS

A total of 101 short-stem and 74 conventional arthroplasties were included, with an average follow-up of 9.82 (7-14) years. HHS functional score and SF-36 were excellent in both implants and no significant difference between them (p > 0.05) was found. However, "thigh pain" was present in 7 patients with conventional stems and none with short-stems (p < 0.001). The survival rate at 13 years was 99%, for both implants, and no significant differences were found between them (χ²(2) = 0.178; p = 0.673). Conventional stems had stress shielding at the greater trochanter in 72% of the cases and 43% at the calcar, being statistically superior (p < 0.001) to the stress shielding observed in the short stems.

CONCLUSION

According to our results, this short-stem seems to allow preservation of bone stock, with decreased stress shielding and also a lower incidence of thigh pain compared to conventional stems.

LEVEL OF EVIDENCE

Level III retrospective comparative study.

Long-Term Survival and Results at a Mean Follow-Up Period of 24 Years of a Tapered Straight, Collarless, Grit-Blasted, Titanium Alloy Stem

BACKGROUND

There is limited evidence on the survivorship of patients who undergo cementless stem implantation, beyond 20 years of the hip arthroplasty. We report implant survival and results of the CLS Spotorno femoral stem until 30 years from implantation.

METHODS

Survival analysis of 147 CLS Spotorno stems in 119 patients for an average period of 24 years (20-30) from the date of implantation was performed. During the course of the follow-up period, 33 patients (39 hips) died. The information on the survival of their hip implant at the time of death was gathered from their relatives and general practitioners. Sixty-six patients (86 hips) undertook the complete survey along with radiographic examination, while 18 subjects (20 hips) were interviewed over the telephone. The factors influencing survival, functional outcomes, and level of satisfaction with surgery were evaluated.

RESULTS

The overall estimated survival of the stems was 89.9% after 30 years (95% confidence interval [CI] 83.5-93.9). Survival with femoral revision for aseptic loosening as an end point was 93.1% (95% CI 87.1-96.4). In the worst-case scenario, an overall implant survival of 77.2% (95 CI% 80.3-82.7) was observed after 24 years. Patients who were older than 50 in age at the time of surgery had better survival rates (P = .026). The mean Harris Hip Score at follow-up was 83.1 (range 43-100) and the level of satisfaction was 9/10. The main determinant of postsurgical satisfaction was Harris Hip Score, whereas radiographic alterations explained little with respect to the variation in the outcomes.

CONCLUSION

The cementless CLS Spotorno stem displayed satisfactory results 24 years after implantation and high estimated survival until 30 years from surgery. However, patients below the age of 50 at the time of surgery have an increased risk of undergoing revision of their femoral stem.

Primary cementless stems in septic hip revision: Indications and results

PURPOSE

The aim of our work is to evaluate results obtained from a cohort of patients affected by periprosthetic joint infection and treated with a primary cementless stem in a two-stage technique framework.

METHODS

Eighty-four patients were evaluated at a mean follow-up of 37.4 months. The main demographic, surgical, clinical, and radiographic data were recorded. A femoral window for stem removal was performed in 33 patients.

RESULTS

Statistically significant improvement was noted for both the Harris Hip score and the Oxford Hip score. Postsurgical complications included thigh pain in three patients, subsidence (>2 mm) in one patient, implant dislocation in two patients, cup revision in one patient, implant revision for septic failure in two patients, and stem revision for varus position in one patient. The stem survivorship rate was 96.3%. There were no significant differences between the groups in which a cortical window was created or not.

CONCLUSION

Femoral stem revision with primary cementless stems is a viable option in selected patients undergoing two-stage hip revision surgery. Correct indication is a cornerstone of good outcome. The use of a cortical window does not affect the final outcome or implant survivorship rate.

Uncemented short stems in primary total hip arthroplasty: The state of the art

Over the last two decades, several conservative femoral prostheses have been designed. The goals of conservative stems include: the spearing of the trochanteric bone stock; a more physiological loading in the proximal femur reducing the risk of stress shielding; and to avoid a long stem into the diaphysis preventing impingement with the femoral cortex and thigh pain.

All stems designed to be less invasive than conventional uncemented stems are commonly named ‘short stems’. However, this term is misleading because it refers to a heterogeneous group of stems deeply different in terms of design, biomechanics and bearing. In the short-term follow-up, all conservative stems provided excellent survivorship. However, variable rates of complications were reported, including stem malalignment, incorrect stem sizing and intra-operative fracture.

Radiostereometric analysis (RSA) studies demonstrated that some conservative stems were affected by an early slight migration and rotation within the first months after surgery, followed by a secondary stable fixation. Dual-energy x-ray absorptiometry (DEXA) studies demonstrated an implant-specific pattern of bone remodelling.

Although the vast majority of stems demonstrated a good osseointegration, some prostheses transferred loads particularly to the lateral and distal-medial regions, favouring proximal stress shielding and bone atrophy in the great trochanter and calcar regions.

Cite this article: EFORT Open Rev 2018;3:149-159. DOI: 10.1302/2058-5241.3.170052

Long-term bone remodelling around 'legendary' cementless femoral stems

Bone remodelling around a stem is an unavoidable long-term physiological process highly related to implant design. For some predisposed patients, it can lead to periprosthetic bone loss secondary to severe stress-shielding, which is thought to be detrimental by contributing to late loosening, late periprosthetic fracture, and thus rendering revision surgery more complicated.However, these concerns remain theoretical, since late loosening has yet to be documented among bone ingrowth cementless stems demonstrating periprosthetic bone loss associated with stress-shielding.Because none of the stems replicate the physiological load pattern on the proximal femur, each stem design is associated with a specific load pattern leading to specific adaptive periprosthetic bone remodelling. In their daily practice, orthopaedic surgeons need to differentiate physiological long-term bone remodelling patterns from pathological conditions such as loosening, sepsis or osteolysis.To aid in that process, we decided to clarify the behaviour of the five most used femoral stems. In order to provide translational knowledge, we decided to gather the designers' and experts' knowledge and experience related to the design rationale and the long-term bone remodelling of the following femoral stems we deemed 'legendary' and still commonly used: Corail (Depuy); Taperloc (Biomet); AML (Depuy); Alloclassic (Zimmer); and CLS-Spotorno (Zimmer). Cite this article: EFORT Open Rev 2018;3:45-57. DOI: 10.1302/2058-5241.3.170024.

Seventeen-year survival of the cementless CLS Spotorno stem

INTRODUCTION

For primary uncemented hip arthroplasty, various stem designs are available. The cementless CLS((R)) Spotorno stem has been used for more than 20 years. We re-evaluated a group of patients previously examined for a 10-year follow-up to assess the clinical and radiological stem performance in the long run.

MATERIALS AND METHODS

Between 1987 and 1988, a consecutive series of 107 uncemented CLS((R))-Spotorno stems (Zimmer Ltd., Germany) were implanted in 94 patients. The patients' mean age at the time of surgery was 51 years (range 20-77 years); 80 hips out of 107 (86%) were available for a clinical examination [Harris Hip Score (HHS)] after a mean of 17 years (range 15-18 years). In addition, radiographs were available from 74 out of 80 examined hips (92%) and analyzed for radiolucency, stress shielding, stem migration and heterotopic ossification.

RESULTS

Stable stem fixation was present in 64 hips (98.5%). With "non-traumatic loosening" as an endpoint, stem survival was 100% after 17 years. Two stems (3%) showed mild subsidence already in the 10-year follow-up with no progression after 17 years. The HHS described excellent results in 47 hips (59%), good results in 16 hips (20%) and fair or poor results in 7 hips (9%) and 10 hips (13%), respectively. Radiolucency and grades II and III stress shielding were progressive at 17 years compared with the 10-year results. Grade IV stress shielding associated with osteolysis was seen in 9 hips (14%). Thigh pain was present in 20 hips (25%).

CONCLUSION

The CLS((R)) Spotorno stem allows excellent long-term results in cementless hip arthroplasty, leaving only minimal options for substantial improvements. Our findings on progressive stress shielding point towards a more diaphyseal load transfer of the CLS stem.

Second-generation uncemented stems: excellent 5-13-year results

INTRODUCTION

The purpose of this study was to prospectively evaluate the 5-13-year results of a cementless total hip arthroplasty with a special focus on the survivorship,occurrence of osteolysis, incidence of intraoperative femoral fractures, thigh pain, and cortical hypertrophy of the femoral stem. The femoral component used in this study was titanium fluted, slotted, symmetrical component that was prepared with intraoperative machining. The proximal third of the stem had hydroxyl-apatite coating and horizontal steps.

METHODS

The clinical and radiographical results of a consecutive series of 157 total hip arthroplasties (124 patients)with this stem were investigated. Minimum follow-up was 5 years. The average age of the patients at the time of surgery was 47 years. Three patients died and ten patients were lost to follow-up, leaving 142 hips for evaluation. The clinical result was evaluated on the basis of the Merled’Aubigné score, complications and thigh pain. A detailed radiographic analysis was performed at each follow-up visit. Kaplan–Meier survivorship analysis was performed to evaluate stem, cup, and bearing survivorship.

RESULTS

The mean follow-up was 8.5 years (range 5-13 years). The average Merle d’Aubigné score improved from 10.5 points preoperatively to 17.4 points postoperatively.The cumulative 10-year survival rate was 99% for the femoral component, 99% for the acetabular component,and 69% for the bearing. Thigh pain was identified in three patients (2%). There was no distal femoral osteolysis.Seventy-nine percent of all the hips had endosteal spot welds around the coated, proximal one-third of the prosthesis.51% had radio dense lines around the distal tip of the prosthesis,and 3% had cortical hypertrophy. One undersized stem and one cup were revised for aseptic loosening, and 25 bearings were exchanged.

CONCLUSIONS

Uncemented, machined, fluted titanium canal-filling femoral components achieve reliable fixation in this young patient population. They have a decreased incidence of activity-related thigh pain, lower rate of intraoperative femur fractures and cortical hypertrophy with comparable bone-ingrowth in comparison to other second generation uncemented femoral components described in literature. Bearing wear and the need for bearing exchange was the only limitation of these constructs.

Primary total hip arthroplasty for displaced intracapsular fracture of the femoral neck: Medium-term functional and radiographic outcomes

The number of complications after primary total hip arthroplasty for displaced intracapsular fractures of the femoral neck is higher than that after operations for osteoarthritis. The aim of this study is to evaluate the number of complications and mid-term functional and radiological findings of patients after primary THA for displaced intracapsular fractures of the femoral neck. Between 1995 and 1998, we operated on a total of 89 patients for acute displaced intracapsular fractures of the femoral neck, i.e. Garden Type 3 and 4. In all the patients we evaluated intraoperative and early postoperative complications. We reviewed clinical and radiological results in 65 patients. The only intraoperative complication was abruption of the greater trochanter. Early postoperative complications occurred in 13 patients (15%). The specific complications, THA dislocation, occurred in 3 patients. Non-specific complications were recorded in 10 patients. No delayed healing of the surgical wound, neural lesion or early, delayed or late infection was recorded. Of 65 patients followed-up for an average of 78 months (range, 62–109 months), 8 patients underwent revision surgery. Of 57 patients with primary THA, very good and good clinical results according to the Harris Hip Score were recorded in 48 patients (84%) and poor results in only 2 patients (4%). Nine of 57 followed-up patients showed radiological signs of loosening (16%). The radiolucent line could be seen in 3 patients in the region of the cup, in 1 patient in the region of the femoral component and in 5 patients in both components. Clinical complaints that would result in indication for reimplantation were recorded in none of the mentioned patients. Number of complications, functional results and resumption of full self-reliance by patients after THA for an intracapsular fracture of the femoral neck are so positive that we consider the indication of THA for a displaced femoral neck fracture fully justified.

Revision hip surgery using the CLS expansion shell

The aim of our study is to assess the outcomes using the uncemented CLS expansion shell in revision hip surgery for aseptic loosening of the acetabular component. Between 1991 and 2000 we used the CLS expansion shell in revision hip surgery in 215 patients (230 hips). We were able to evaluate 196 patients (211 hips) with failed acetabular components. The male/female ratio was 82/114 and the mean age of the patients was 63 years (range 38-71). The main reason for revision was aseptic loosening of the PE cup (184 patients). There were 79 hips with Paprosky defect of the acetabulum type I, 62 hips with type 2A, 57 hips with type 2B and 13 hips with type 2C in the study. The mean follow-up was 8.5 years (range 5-14). Plain radiographs using an AP view of the pelvis and AP and lateral views of the affected hip were taken immediately after surgery and at the latest follow-up. Clinical outcomes were determined using the Merle dAubigne' and Postel score and the Harris Hip score. The mean preoperative Merle dAubigne' score was 7.8 points (range 6.9 to 9.9); at the latest follow-up it was 14.9 points (range: 12.5 to 15.9). The mean preoperative Harris Hip score was 38.6 points (range: 32 to 59); at the latest follow-up it was 82.5 points (range: 38 to 95). Osteointegration of the CLS expansion shell was present in 149 hips (70.6%) at the latest follow-up. There were 31 complications (15%) requiring a second revision. Clinical survivorship of the CLS expansion shell was 90% at five years and 84% at 8.5 years after revision surgery. Radiological survivorship was 78% at five years and 70% at 8.5 years after revision surgery. The CLS expansion shell offers a viable alternative for revision hip surgery with lower bone quality, insufficient bone at the bottom and cavitary defects of the acetabulum.;

Zementfreie Hüftschäfte

Optimal fixation of cementless stems is a precondition for long-lasting stability. Thus, anchorage, stabilizers, material and surface are of essential importance. To achieve primary stability, good rotational, tilting and axial stability is necessary. Stabilizers such as fins and ribs optimize stability. The CCD-angle and length of neck-axis determine the offset (laterality), leg-length and center of rotation. The stem, is responsible for the fixation of the prosthesis and for transmitting forces to the bone. The types of fixation are epiphyseal (the femoral head is covered by a cup prosthesis), metaphyseal and meta-diaphyseal (with straight or anatomically shaped monoblock-prostheses of different lengths, modular and custom-made prostheses) and diaphyseal (using predominantly modular systems). Titanium alloys are the predominate material for cementless stems. The surfaces are generally corundum-blasted or plasma sprayed. For metaphyseal and meta-diaphyseal stems, survival rates from 95 to 98% have been reached after 15 years. Diaphyseal-fixed stems have mid-term survival-rates of 92-99%.

The CLS uncemented expansion cup: six cases of component failure

We report six cases of fracture of the metal backing of the CLS expansion cup. The aim of this paper is to draw attention to this mode of failure and recommend that in cases of unexplained hip pain in those with a CLS acetabular component X-rays in at least two planes are performed. (Hip International 2004; 14: 28-33).

Anatomically adapted, HA coated SBG stem – Ten years of successful implantation / Anatomisch adaptierte, HA beschichtete SBG Prothese – 10 Jahre erfolgreiche Anwendung

For stable implantation of anatomically conforming femur prostheses, modifications that accommodate curving and torsion are necessary. In accordance to this concept, the anatomically shaped SBG stem has been developed. The first consecutive implantations were evaluated. 194 primary arthroplasties with uncemented anatomical, HA coated SBG stems were performed. Mean patient age was 61 years. 143 patients with 151 (78%) SBG stems were followed-up clinically and radiologically after an average of 10 (9-11) years. So far, only one implant had to be revised. Survivorship with revision of the femoral component is 99.5% at ten years. The mean postoperative Harris Hip Score was 92. Patients over 75 years had a score of 89; younger patients under 40 years scored 94. Sclerotic lines were seen in zone I or VII in 8%. Minor femoral remodeling (Type 1) occurred proximally in 75%. Minor thickening of the femur at the level of the tip of the prosthesis could be observed in 27% of the cases. There is no correlation between compacta thickening and clinical symptoms (p=0.15). The anatomical shape, the oval diameter and the longitudinal grooves secure stable primary fixation. Together with the HA coating, which enhances osseointegration, the SBG stem has a high success rate in the medium and long term.