Seventeen-year survival of the cementless CLS Spotorno stem

Does Mal-alignment of the CLS Spotorno Femoral Stem Correlate with Functional Outcome of Patients Undergoing Total Hip Arthroplasty? An Evaluation at Mid-term Follow Up

Background

The straight and thin design of the CLS Spotorno stem makes it prone for coronal plane mal-alignment, with potential for cortical impingement; reactive osteogenesis and thigh pain have been documented in this situation with some stems. The literature is scarce about the effect of distal mal-alignment with this particular stem, and its relationship with thigh pain, functional outcomes and stem survival. We assessed functional outcomes with incidence of varus/valgus CLS stem alignment, and correlated stem subsidence of these thin stems with hip scores.

Methodology

Hip arthroplasty cases with CLS Spotorno stems, operated between 2015 and 2022, with a minimum follow up of 18 months were evaluated. Radiology included 100% pelvis x-rays with bilateral hips (anteroposterior with 15° internal rotation plus lateral views); parameters documented were coronal mal-alignment, stem subsidence, any pedestal formation and heterotrophic ossification (HO); special note was made of any thigh pain, and functional outcomes were recorded using mHHS and SF-36 scores.

Results

We evaluated 65 patients with 79 operated hips at an average follow up of 5.26 years. 31.6% (25/79) stems were neutrally aligned, 64.6% (51/79) were in varus alignment and 3.8% (3/79) were in valgus alignment. The mean subsidence was 3.15 mm + 2.26 and 3 cases had Pedestal formation at the stem tip. There was no correlation between varus/valgus stem positions with the mHHS (p = 0.271) and SF-36 score (p = 0.553), which also did not correlate with the stem subsidence. HO formation was seen in 16 hips (20.3%), but no cases in our series needed revision during follow up.

Conclusion

Significant distal malalignment with some subsidence were noted in the hips studied; despite these radiological issues, there were excellent mid-term outcomes and good stems survival, implying that distal malposition may have no bearing on functional outcomes.

Long-term survival and complication rate of cementless prosthetic stems in primary total hip arthroplasty categorized by types according to Mont classification: a regional registry-based study on 53,626 implants

INTRODUCTION

The purpose of this retrospective registry-based study is to assess survival and causes of failure of cementless stem implants used in total hip arthroplasty (THAs), to ascertain if there are differences when these are categorized according to the six types described by Mont.

METHODS

Data collected from the regional registry regarding all primary THAs performed from 2000 to 2019 were analyzed. Femoral prosthetic stems were divided into the six types of Mont classification. For each stem type, number of implants, survival and causes of failure were evaluated and compared.

RESULTS

The most frequently implanted stem type was the 3c type (53.4%). Type 1 had the lowest stem failure rate (1.6%), and type 6 showed the highest (3.9%). Periprosthetic fracture was the most frequent complication in type 6, accounting for 34.5% of failures. Aseptic loosening was the main complication in type 2 stems, accounting for 36.4% of failures. Pairwise comparisons showed significant higher survival of type 1 compared to type 3c (p = 0.000026) and type 6 (p = 0.000076), and between type 3a compared to type 3c (p = 0.03) and type 6 (p = 0.026).

CONCLUSION

Significant variations in implant survival rates were found among the six Mont-types of cementless stems. These findings emphasize the paramount importance of stem design and fixation area in determining long-term survival, providing a guidance for orthopedic surgeons in the selection of the most appropriate stem for primary THA, contributing to our understanding of cementless stem performance, presenting invaluable insights to further improve patient outcomes in THA surgery.

Is a Total Hip Arthroplasty Stem in Varus a Risk Factor of Long-Term Mechanical Complication?

BACKGROUND

The impact of implanting cementless femoral stems in varus alignment on long-term mechanical complications remains poorly defined in the literature. The aim of our study was to compare survivorship and functional and radiographic outcomes of stems in varus alignment to those in neutral alignment with and average follow-up of 10 years.

METHODS

This single-center, multisurgeon, retrospective case-control study compared a group of 105 total hip arthroplasty (THA) patients who had varus stem alignment (Varus Stem) to a matching group of 105 THA patients who had neutral stem alignment, operated on between January 2007 and December 2012. The primary outcome measure was implant survival. Secondary outcomes included functional (Harris Hip Score, Postel Merle d'Aubigné Score, thigh pain, dislocation and hip range of motion) and radiographic outcomes (radiolucency, osseointegration, heterotopic ossification, subsidence, and stress shielding).

RESULTS

There was no significant difference in implant survival between the 2 groups with 95.7% (±2.46) in the Varus Stem group versus 97.7% (±1.64) in the Neutral Stem group (P = .41) after an average follow-up of 10 years. There was no significant difference in clinical and radiographic outcomes between groups.

CONCLUSION

Cementless femoral stems in varus alignment were not the cause of mechanical complications with an average follow-up of 10 years. The comparison between groups in terms of implant survival, functional, and radiographic outcomes does not show any significant differences. Positioning a femoral stem in varus alignment may be an alternative for surgeons wishing to restore preoperative offset and to ensure satisfactory hip stability.

Results of Hip Arthroplasty Using a COREN Stem at a Minimum of Ten Years

Purpose

We report on the 10-year clinical hip function and radiologic outcomes of patients who underwent hip arthroplasty using a COREN stem.

Materials and Methods

A consecutive series of 224 primary cementless hip arthroplasty implantations were performed using a COREN stem between 2009 and 2011; among these, evaluation of 128 hips was performed during a minimum follow-up period of 10 years. The mean age of patients was 65.4 years (range, 40-82 years) and the mean duration of follow-up was 10.8 years (range, 10-12 years). Evaluation of clinical hip function and radiologic implant outcomes was performed according to clinical score, thigh pain, and radiologic analysis.

Results

Dramatic improvement of the mean Harris hip score (HHS) from 59.4 preoperatively to 93.5 was observed at the final follow-up (P≤0.01). Stable fixation was demonstrated for all implants with no change in position except for one case of Vancouver type B2 periprosthetic femur fracture. A radiolucent line (RLL) was observed in 16 hips (12.5%). Thigh pain was observed in only two hips (1.6%) at the final follow-up. There were no cases of osteolysis around the stem. The survival rate for the COREN stem was 97.7%.

Conclusion

Good long-term survival with excellent clinical and radiological outcomes can be achieved using the COREN femoral stem regardless of Dorr type.

Twenty-year results of a neck-preserving short-stem prosthesis in primary total hip arthroplasty

PURPOSE

The use of short-stemmed femoral components with preservation of the femoral neck has been advocated for younger and more active patients undergoing joint replacement. This study reports the long-term outcomes of the Collum Femoris-Preserving (CFP) prosthesis on a previous report.

METHODS

Between January 1999 and December 2000, a total of 149 patients underwent total hip arthroplasty procedure using the CFP stem in a single institution. At latest follow-up, 79 patients were available and were included in this study. The mean age of the cohort was 73.4 (range, 44-92 years) with a mean follow-up of 20.7 years (range 20-21). The average age was 52.1 years at index procedure (range, 21-71 years).

RESULTS

The Kaplan-Meier survivorship free from revision for any cause at 5, 10 and 20 years was 93.2% (87.8-96.3%), 93.2% (87.8-96.3%) and 83.0% (75.7-88.3%), respectively. At 20 years follow-up, the revision for any cause occurred in 26.6% (21 of 79) of patients. The most common causes for revision surgery were aseptic loosening, dislocation, and polyethylene wear with 6.3% (5 out of 79), respectively. Periprosthetic fracture occurred in four patients (5.1%) followed by periprosthetic joint infection in two patients (2.5%). Revision surgery of the femoral stem was required in four patients (5.1%). There was a statistically significant improvement of the Harris Hip Scores from 53 to 83.7 (range 56-91).

CONCLUSION

The long-term outcomes of the CFP stem are excellent, demonstrating a low rate of aseptic loosening with an excellent survivorship within 2 decades.

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.

MINIMA Short Stem Versus Standard Profemur (TL) Stem in Primary Total Hip Replacement: A Comparative Study

Background: The objective of our study was to compare a novel squared section, tapered design - with four conicity - short stem, the MINIMA® short stem with the cementless Profemur® TL standard femoral stem in primary total hip arthroplasty (THA) in terms of functional outcomes, radiologic evaluation and other peri-operative and post-operative data.

Material and methods: This is a comparative study including 46 patients undergoing primary THA. In 23 patients, the MINIMA® short stem was used. These patients were matched with another 23 patients in whom a cementless Profemur® TL standard femoral stem was used. The levels of the pain were evaluated according to the Visual Analog Scale/Numerical Rating Scale (VAS/NRS). The functional and clinical evaluation of the patients was performed with Harris Hip Score (HHS), Charnley’s Hip score, EuroQol (EQ-5D)-(EQ-100), Patient Health Questionnaire (PHQ-9), and neuropathic pain questionnaire (DN-4). The rest of the comparison data included demographic data, the American Society of Anesthesiologists score (ASA), Charlson Index score, the pre-operative diagnosis, radiographic evaluation, the days of hospitalization, the operating time, incision length, blood loss, and blood transfusion requirements and complication rates.

Results: The two cohorts had comparable results regarding all patients’ peri-operative data. The radiographic assessment revealed considerable higher levels of femoral offset and femoral subsidence for the MINIMA group, but within acceptable limits for both cohorts. The majority of the functional and other scores did not give strong prominence to one specific femoral stem.

Conclusion: Our comparative study underlined the efficacy of the MINIMA® short stem, due to the fact that it revealed comparable and, in some cases, relatively better short-term outcomes compared with the TL standard femoral stem. Yet, more well-designed long-term research is required in order to further establish its effectiveness.

Long-Term results of total Hip Arthroplasty performed using a cementless expansive Acetabular Cup and Spotorno Femoral Stem

Objective

In this study we aimed to investigate the long-term clinical and radiological results, revision rates and causes, and the rate of implant survival in total hip arthroplasty performed using CLS^® expansion cup and Spotorno^® cementless femoral stem.

Methods

Clinical results of total hip arthroplasty performed on 131 hips of 114 patients in Istanbul Training and Research Hospital between 1993 and 2003 were retrospectively evaluated according to the Harris Hip Score. Revision rates were determined and implant survival rates were identified using the Kaplan-Meier estimator.

Results

Of the patients, 39 were males and 75 were females. The average age of the patients at surgery was 48.7±11.3 years. Patients were followed up for a mean period of 13.9±2.4 years. The mean Harris Hip Score was 34.35±6.09 preoperatively and 88.20±7.11 at the final follow-up (p<0.001). The Kaplan-Meier survivorship estimate for the cup at 13.9 years, taking revision for any reason as the end point was 95.6% (95% CI), while the 15^th and 17^th year survival rates were 90% and 85%, respectively.

Conclusion

In total hip arthroplasty using a cementless expansive acetabular cup, a 95.6% survival rate is achieved after an average of 14 years, whereas the rate decreases to 85% after 17 years. Even if the incidence of cup breakage is reduced with proper implantation, particle disease and periacetabular osteolysis remains a problem for the long-term survival.

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.

A Large-Scale Fifteen-Year Minimum Survivorship of a Cementless Triple Tapered Femoral Stem

BACKGROUND

This study reports the long-term outcomes of a metaphyseal fit-and-fill cementless femoral component in total hip arthroplasty (THA) with a follow-up of 15-19 years.

METHODS

We conducted a retrospective review of 376 consecutive THAs (345 patients), using a triple tapered stem performed between 2000 and 2003 with a view to assessing survivorship and radiological and functional outcomes. Images were assessed for initial alignment, terminal osteolysis, or subsidence, while clinical outcomes were assessed using the St Michael's Hip Score.

RESULTS

Forty-five (11.9%) hips were lost to follow-up, 20 (5.31%) had died before our 15-year cutoff follow-up, and 4 (1.06%) had declined follow-up early on, leaving 307 hips (81.64%, 276 patients) available for both clinical and radiological follow-up at a minimum of 15 years (range 15-19). The mean age at the time of operation was 49.6 years (range 19-71) and the cohort included 131 (42.67%) male and 145 (47.23%) female patients. Seven stems (2.28%) were revised: 4 due to periprosthetic fractures, 2 for periprosthetic joint infection, and 1 for adverse reaction to metal debris at the trunnion. The St Michael's Hip Score improved from 14.2 (range 9-23) preoperatively to 22.3 (range 13 to 25) at the last documented follow-up (P = .000). Kaplan-Meier survivorship with stem revision for any reason as the end point was 97.70%. Worst-case scenario Kaplan-Meier survivorship, where all lost to follow-up are considered as failures, was 85.3%. No stem was revised for aseptic loosening.

CONCLUSION

This triple tapered stem in THA shows excellent survivorship beyond a minimum of 15 years.

No effect of femoral canal jet-lavage on the stability of cementless stems in primary hip arthroplasty: a randomised RSA study with 6 years follow-up

INTRODUCTION

In contrast to cemented hip prostheses, the effect of washing the bone bed with jet-lavage prior to insertion of cementless stem components in primary hip arthroplasty (THA) is unclear. Jet-lavage potentially decreases the risk of fat embolisation during rasping and stem insertion and might help in avoiding bacterial contamination. An earlier animal study has shown less debris and better-organised trabecular structure of new bone when jet-lavage was used. We hypothesised that the primary stability of cementless femoral stems implanted after jet-lavage of the femoral canal prior to stem insertion would improve with earlier stabilisation, as measured with Radiostereometry (RSA), compared with insertion without prior jet-lavage.

METHODS

40 patients with primary osteoarthritis operated on with a cementless titanium grit blasted stem are included in the study. The patients were randomised to either jet-lavage or control without any lavage of the femoral canal prior to insertion of the prosthesis. The stem migration pattern was measured with RSA at 0, 3, 12, 24 and 72 months.

RESULTS

At 6 years, 19 patients remained for analysis in the jet-lavage and 18 in the control group. We found no difference in extent or pattern of migration as measured with RSA. Both groups seemed to have stabilised within 3 months after a slight subsidence and retroversion. No stem was revised or considered loose as measured with RSA.

CONCLUSIONS

Washing the bone bed with jet-lavage prior to insertion of cementless stems does not affect the stability of cementless femoral components. No adverse effects were observed.

Anatomic grooved stem mitigates strain shielding compared to established total hip arthroplasty stem designs in finite-element models

Aseptic loosening remains a major problem for uncemented femoral components in primary total hip arthroplasty (THA). Ideally, bone adaptation after THA manifests minimally and local bone density reduction is widely avoided. Different design features may help to approximate initial, post-THA bone strain to levels pre-THA. Strain-shielding effects of different SP-CL stem design features are systematically analyzed and compared to CLS Spotorno and CORAIL using finite element models and physiological musculoskeletal loading conditions. All designs show substantial proximal strain-shielding: 50% reduced medial surface strain, 40–50% reduction at lateral surface, >120 µm/m root mean square error (RMSE) compared to intact bone in Gruen zone 1 and >60 µm/m RMSE in Gruen zones 2, 6, and 7. Geometrical changes (ribs, grooves, cross sections, stem length, anatomic curvature) have a considerable effect on strain-shielding; up to 20%. Combinations of reduced stem stiffness with larger proximal contact area (anatomically curved, grooves) lead to less strain-shielding compared to clinically established implant designs. We found that only the combination of a structurally flexible stem with anatomical curvature and grooves improves strain-shielding compared to other designs. The clinical implications in vivo of this initial strain-shielding difference are currently under evaluation in an ongoing clinical analysis.

Mid-term results of an uncemented tapered femoral stem and various factors affecting survivorship

OBJECTIVE

CLS stem is commonly used today in primary hip arthroplasty, but only a few studies have evaluated their outcome in young high demanding patients. In Indian scenario, many patients require squatting and sitting cross-legged as part of their daily activities placing excessive load on the joint. We evaluated (I) Mid-long term functional and radiological results (II) Influence of age, gender, diagnosis, stem alignment, Canal fill index (CFI) on the outcome (III) Kaplan-Meier survivorship using revision for any reason or for aseptic loosening as an endpoint.

METHODS

Retrospective evaluation of 64 THA in 54 patients operated between July 2000 to July 2011 using CLS stem was done. Mean follow-up was 10.3 years (5-14.9 years) with 5 patients lost to follow-up and 4 patients died. Mean age at surgery was 46.8 years (18-78 years).

RESULTS

Mean Harris hip score was 89.4 (72-100). Thigh pain was present in 4 hips which were not associated with the sizing of the stem (p = .489). Stable fixation by bony ingrowth was seen in 53 hips (96.4%) and by fibrous ingrowth in 2 cases (3.6%) with no case of loosening seen. Stress shielding was seen as Grade II in 17 hips (30.9%), Grade III in 3 hips (5.4%). Pedestal formation was seen in 9 hips (16.4%) which were statistically associated with varus alignment and CFI < 80. No stem revision was performed with stem survivorship of 100%.

CONCLUSION

The mid-term survival rates and good clinical-radiological outcomes of CLS stem in high demanding Indian population were excellent.

Long term survival analysis of cementless Spotorno femoral stem in young patients

Objective

The aim of this study was to analyze the survivorship and clinical outcome of Cementless Spotorno (CLS) stem in young patients.

Methods

A total of 99 consecutive hip arthroplasties using CLS stem were performed on 84 patients younger than 50 years of age between 1993 and 2001. 63 patients were available for final follow-up (mean age: 39 ± 7.8 (range: 22–50)). Patients' Harris Hip Scores (HHS) and survivorship estimates were calculated. Radiographs were analyzed for acetabular implant status, canal fill index (CFI), stem alignment, osteolysis, and stress shielding.

Results

Mean follow-up time was 18 years (13–3), and mean HHS was 88.7 (58–100). Patients with femoral neck fracture had a more favorable functional outcome (p = 0.027), while those with stems in varus had lower scores (p = 0.017). 31 stems (49%) were undersized and 30 hips (47%) had perifemoral osteolysis. Acetabular impairment was strongly associated with osteolysis in Gruen zones 1 and 7 (p < 0.01). Seventeen of the osteolytic lesions occurred in Gruen zone 1, 4 lesions in zone 2, 9 in zone 6 and 22 in zone 7. Forty nine stems were well aligned, 10 were in varus and 5 in valgus. Six patients presented with grade 1 stress shielding, 42 with grade 2, 9 with grade 3 and 7 with grade 4. Pedestal formation was evident in 13 cases. Kaplan-Meier survivorship estimates at 18 years with revision for any reason as the end point and with septic revisions excluded were 91.2% (95% CI: 83.7%–98.7%) and 95.1% (95% CI: 89.5%–100%), respectively. There was no difference between survival estimates of patients with different etiologies.

Conclusion

CLS stems in young patients have high survival estimates in the long term with good-excellent results. Spotorno stems perform equally well in all etiologies with no difference in terms of survivorship.

Level of Evidence

Level IV Therapeutic study.

Hip Arthroplasty Using the Bencox® Hip System: An Evaluation of a Consecutive Series of One Thousand Cases

Purpose

This is a report on the outcomes associated with a consecutive series of 1,000 cementless hip arthroplasties utilizing the Bencox® hip stem–the first Korean-developed hip prosthesis.

Materials and Methods

A consecutive series of 1,000 hip arthroplasties using the Bencox® hip stem were analyzed, starting from its initial release (September 2006) until June 2014. Patients in this consecutive series underwent surgery for fractures (n=552), arthritis (n=155), avascular necrosis (n=209), and revisions (n=84). Of these 1,000 cases, patients with a minimum follow-up of at least 1 year (n=616) were retrospectively analyzed for radiographic and clinical outcomes (i.e., Harris hip score). The stability of the prosthesis was evaluated by examining subsidence.

Results

During the follow-up period (mean follow-up period of 54.8 months), there were 2 cases requiring revision of the femoral stem–both were caused by periprosthetic fractures and neither involved stem loosening. The mean Harris hip score during follow-up was 95.5. Bone ongrowth occurred in 95% of patients; no cases of subsidence or aseptic loosening of the stem were detected, and no cases of postoperative complications such as ceramic breakage were observed.

Conclusion

Clinical and radiographic evaluations of hip arthroplasty using the Bencox® hip stem revealed excellent outcomes with an average of 54.8 month follow-up in a consecutive series of 1,000 cases.

A Wedge-Shaped Uncemented Femoral Component: Survivorship in Patients Younger Than 50 Years at a Mean Follow-Up of 22 Years

BACKGROUND

This study presents the results of the long-term survival of a wedge-shaped uncemented femoral component in a cohort of young patients with a follow-up of 20-25 years.

METHODS

In a consecutive series of 85 patients (100 hips), aged less than 50 years at the time of primary total hip arthroplasty, the long-term survival of the Cementless Spotorno femoral component was analyzed by performing a Kaplan-Meier survival analysis (95% confidence interval [CI]).

RESULTS

The mean follow-up was 22 years (range, 19.7-25.5). The clinical and radiographic outcomes were satisfactory. The overall survival rate of the femoral component was 93.4% after 23.8 years (95% CI, 85.9%-97.0%). Survival with revision for aseptic loosening as the end point was 94.4% (95% CI, 87.0%-97.6%) after 23.8 years.

CONCLUSION

This study shows an excellent long-term survival of this specific wedge-shaped uncemented femoral component after 20 to 25 years in patients younger than 50 years.

Survival Rate of Short-Stem Hip Prostheses: A Comparative Analysis of Clinical Studies and National Arthroplasty Registers

BACKGROUND

The primary aim was to evaluate the outcome of short-stem hip prostheses in terms of overall revision rates. Data were taken from published literature and national arthroplasty registers. The second study aim was to evaluate a potentially superior outcome of dependent compared to independent clinical studies.

METHODS

All clinical studies on short-stem hip prostheses between 2006 and 2016 were reviewed and evaluated with a special interest on revision rates. Revision rate was calculated as "revision per 100 component years." Short stems were divided into femoral neck retaining (NR), neck sparing (NS), and neck harming (NH) prostheses. Published literature was further classified into dependent and independent studies, and data were compared to the Australian National Arthroplasty Register.

RESULTS

Fifty-two studies with 56 cohorts met the inclusion criteria and were therefore included in our study. All clinical studies showed a median revision rate of 4.8% after 10 years. NS and NH stems performed equally, whereas neck retaining prostheses were significantly inferior. Independent showed higher revision rates compared to dependent data without being statistically significant. The Australian register revealed a revision rate of 6.6% after one decade.

CONCLUSION

Similar low revision rates for NS and NH short-stem prostheses were found in the included data. Dependent studies seem not to be biased with regard to the longevity of short-stem hip replacement. Longer follow-up periods in clinical studies and more detailed information in arthroplasty registers would be desirable for future studies.

Comparison of an Uncemented Tapered Stem Design in Cobalt-Chrome vs Titanium at 15-Year Follow-Up

BACKGROUND

Cobalt-chromium (Co-Cr) and titanium (Ti) have been the most popular materials employed for cementless implants. The purpose of this study was to compare clinical and radiological results of a single stem design with both alloys at long-term follow-up.

METHODS

Two hundred consecutive uncemented stems implanted in 171 patients (100 Co-Cr and 100 Ti implants) between 1999 and 2002 were studied. Mean age of the patients was 60.9 years (range, 20-84). Clinical results were evaluated using the Harris hip score. The presence of thigh pain was also analyzed. Stem fixation was graded according to Engh criteria. Radiolucent lines, osteolysis, and stem subsidence were also analyzed.

RESULTS

At 15-year follow-up, no stems had been revised. Both groups showed similar clinical results with mean Harris hip score of 93.4 (Co-Cr) vs 93.9 (Ti). There was no difference in the rate of thigh pain (11 vs 8.3, respectively, P = .507). Radiolucent lines were more frequent in the Co-Cr group (63.6% vs 35.6%, P < .001).

CONCLUSION

Ti stems showed better osteointegration than Co-Cr stems, with a significantly lower incidence of radiolucent lines. However, this did not affect the clinical results or the appearance of thigh pain.

Outcomes using wedge stem with full hydroxiapatite coverage with a minimum of 5 years' follow-up

INTRODUCTION

Total Hip Arthroplsty (THA) using uncemented stems is a popular practice in the last decades. The implant survivorship is crtitical and a less than 10% revision at 10 years is been propesed for commercialization and use.

OBJECTIVE

To analyse the clinicoradiological results of an uncemented hydroxiapatite covered wedge stem with a 5 years minimum follow up.

MATERIAL AND METHODS

Prospective study, patients aged from 21-75years were included. All patients received an Element stem (Exactech) and uncemented cup with crosslink poly and 32 mm metal head, and posterior approach with piriformis retention was used. Scheduled clinical and radiographic evaluation at 3 weeks, 3-6 month, year and subsequent years using Harris Hip Score and Merle d'Aubigné Postel. Intraoperative and during follow up complications were recorded.

RESULTS

One hundred and fourteen total hip replacements in 104 patients: 54 females and 50 males (52%/48%). Follow-up of 5.7 years (range, 5-6.2years). Average age 56.8years (range, 42-75years). Clinical evaluation the Merle d'Aubigné score improved 6.8 points and from the initianl Harris Hip Score 47.3 to 93.1 points at last follow up. Radiographic evaluation shows osteointegration in all stems. And in 6 cases (5.3% at 3 months subsidence was detected, average 1.4 mm (range 0-2.6 mm) with no clinical manifestation, 3 cases of subsidence were associated to intraoperative fractures (1 greater trochanter and 2 in the calcar area, all resolved with wire cerclaje). Subjective evaluation: 86 cases (82.6%) excellent, 9 patients (8.6%) good, 6 cases (5.9%) satisfactory and 3 cases (2.9%) poor. All poor results linked to the intraoperative complications. No patient lost during follow up period. No femoral pain dislocation or aseptic or loosening detected. All implants were in situ at last follow up.

CONCLUSIONS

The radiological results confirm the benefits of this type of stem with good osteointegration. The clinical and subjective results are promising. With good surgical technical and without complications the risk of aseptic loosening should be absent or minimal.

The Synergy cementless femoral stem in primary total hip arthroplasty at a minimum follow-up of 15 years

AIMS

We report on the outcome of the Synergy cementless femoral stem with a minimum follow-up of 15 years (15 to 17).

PATIENTS AND METHODS

A retrospective review was undertaken of a consecutive series of 112 routine primary cementless total hip arthroplasties (THAs) in 102 patients (112 hips). There were 60 female and 42 male patients with a mean age of 61 years (18 to 82) at the time of surgery. A total of 78 hips in the 69 patients remain in situ; nine hips in eight patients died before 15 years, and 16 hips in 16 patients were revised. Clinical outcome scores and radiographs were available for 94 hips in 85 patients.

RESULTS

In all, four stems were revised. One stem was revised for aseptic loosening; two stems because of deep infection; and one because of periprosthetic femoral fracture. There was a significant improvement in all components of the Western Ontario and McMaster Universities Osteoarthritis Index score at the final follow-up (total: p < 0.001, pain: p < 0.001, stiffness: p < 0.001, function: p < 0.001). The mean Harris Hip Scores improved from 47 points (27 to 59) pre-operatively to 89 points (65 to 100) at the latest follow-up (p < 0.001). Kaplan-Meier survivorship, with stem revision for aseptic loosening as the endpoint, was 98.9% at 15 years (95% confidence interval (CI) 96.9 to 100, number at risk at 15 years: 90) and with stem revision for any reason was 95.7% (95% CI 91.7 to 99.8, number at risk at 15 years: 90).

CONCLUSION

The Synergy cementless femoral stem demonstrates excellent survivorship and functional outcomes at 15 years. Cite this article: Bone Joint J 2017;99-B:29-36.

Clinical outcome of design modifications to the CLS Spotorno Stem in total hip replacement

PURPOSE

historically, the original CLS Spotorno Stem has demonstrated excellent survival. The design of this stem was recently modified, resulting in the introduction of a shorter, modular version (CLS Brevius). The purpose of the current study was to evaluate the functional, radiological and survivorship outcomes of the cementless CLS Brevius Stem in a multi-surgeon, single center, consecutive series study at two years post-surgery.

METHODS

the Authors performed 170 total hip arthroplasties in 155 patients using the shorter, triple-taper stem design (CLS Brevius). The patients' diagnoses were primary hip osteoarthritis (OA) in 74.4%, secondary hip OA in 22.6%, and post-traumatic hip OA in 3%. All operations were performed through a mini-posterior approach, with the patient in the lateral decubitus position. The mean follow-up was 32 months (24-44 months). Outcome was assessed using the Harris Hip Score (HHS).

RESULTS

the mean HHS improved from 32 preoperatively to 92 points at final follow-up, while the stem survival rate was 99.4%. Overall, the results were excellent in148 hips (87%), good in 14 hips (8.2%), fair in six hips (3.6%), and poor in two hips (1.2%). Intraoperative complications included a calcar fissure in three hips (1.7%). Correct femoral offset was reproduced in 97% while the planned center of hip rotation was achieved in 98%. Only one hip underwent early stem revision; this was due to major subsidence.

CONCLUSIONS

the modified CLS stem design showed excellent short-term results with a low rate of early postoperative complications. One of the main findings of this study was the high correlation between the planned femoral offset and center of hip rotation and the final radiographic measurements. This high reproducibility, which indicates the ability of the system to restore normal hip anatomy, is indeed due to the extensive modularity that characterizes this stem system. Long-term follow-up studies are necessary to fully compare the outcomes of the new design with its highly successful predecessor.

LEVEL OF EVIDENCE

Level IV, therapeutic cases series.

Can a Conical Implant Successfully Address Complex Anatomy in Primary THA? Radiographs and Hip Scores at Early Followup

BACKGROUND

Total hip arthroplasty (THA) in patients with small or abnormal proximal femoral anatomy is challenging as a result of complex anatomic deformities in the hip. It is unclear which stem is the most appropriate for these patients. One possible implant design that may help meet this need is the modified Wagner Cone prosthesis, whose design consists of monoblock cone with splines; however, to our knowledge, no clinical results have been published using this implant.

QUESTIONS/PURPOSES

We evaluated the hip scores and radiographic results (including signs of osseointegration and subsidence) of complex primary THA using the modified Wagner Cone cementless femoral component in patients with small or abnormal proximal femoral anatomic proportions.

METHODS

Between 2006 and 2011, we performed 59 THAs on patients whose femoral geometry precluded the use of standard-sized implants. Of these, 49 (83%) received the modified Wagner Cone prosthesis. During this time, our indications for use of the Wagner Cone implant in such patients included: femoral neck retroversion, excessive anteversion of the femoral neck, or small proximal femora not suitable for standard implants. Of those, 40 patients with 49 THAs were available for radiographic and clinical followup at a minimum of 3 years, and no patients were lost to followup. The diagnosis included developmental dysplasia of hip (22 patients, 28 hips), secondary trauma or posttuberculosis osteoarthritis (nine patients, 10 hips), and hip disease secondary to other disorders (eight patients, nine hips) and osteonecrosis (one patients, two hips). Two versions of the stem with 135° (28 hips) or 125° (21 hips) neck angle versions were used to reestablish normal hip biomechanics. Version angle was chosen based on preoperative templating. Cementless cups with screws were used for the acetabulum. Mean followup was 4 years (range, 3-7 years). Study endpoints were the Harris hip score and radiographic evaluations by a surgeon not involved in the clinical care of the patients (QZ); radiographic analysis included evaluating for the presence or absence of signs of osseointegration (including Engh's criteria) and subsidence.

RESULTS

The Harris hip score improved from a mean of 41 ± 9 preoperatively to a mean of 85 ± 10 at last followup (p < 0.01). The mean vertical subsidence was 1.5 ± 1.1 mm. Radiographic evaluation demonstrated stability (no further subsidence) of all implants at last followup. Endosteal spot welds were found in 32 hips (65%). No progressive radiolucencies were observed. One patient (one hip) underwent revision surgery as a result of late infection; no other revisions were performed.

CONCLUSIONS

The modified Wagner Cone femoral stem has provided improvements in hip scores and promising short-term radiographic results at short-term followup in complex cementless THA associated with abnormal or small femoral anatomical proportions in which standard implants are inappropriate. Longer followup will be needed to see if these results endure. Randomized trials are needed to determine the optimal stem design for these patients.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Bone Mineral Density and Fracture Risk Assessment to Optimize Prosthesis Selection in Total Hip Replacement

The variability in patient outcome and propensity for surgical complications in total hip replacement (THR) necessitates the development of a comprehensive, quantitative methodology for prescribing the optimal type of prosthetic stem: cemented or cementless. The objective of the research presented herein was to describe a novel approach to this problem as a first step towards creating a patient-specific, presurgical application for determining the optimal prosthesis procedure. Finite element analysis (FEA) and bone mineral density (BMD) calculations were performed with ten voluntary primary THR patients to estimate the status of their operative femurs before surgery. A compilation model of the press-fitting procedure was generated to define a fracture risk index (FRI) from incurred forces on the periprosthetic femoral head. Comparing these values to patient age, sex, and gender elicited a high degree of variability between patients grouped by implant procedure, reinforcing the notion that age and gender alone are poor indicators for prescribing prosthesis type. Additionally, correlating FRI and BMD measurements indicated that at least two of the ten patients may have received nonideal implants. This investigation highlights the utility of our model as a foundation for presurgical software applications to assist orthopedic surgeons with selecting THR prostheses.

Survivorship of the cementless Spotorno femoral component in patients under 50 years of age at a mean follow-up of 18.4 years

The long-term survival of the cementless Spotorno CLS femoral component in patients aged > 50 years at the time of arthroplasty was investigated. Survivorship analysis of a consecutive series of 85 patients (100 hips; under 50 years of age at a mean follow-up of 18.4 years (16.3 to 20.8)) was performed. The clinical and radiographic outcomes were satisfactory. The overall rate of survival of the femoral component was 93.5% (95% confidence interval (CI), 90.9 to 96.1) after 19 years. Survival with revision for aseptic loosening as the end point was 95.7% (95% CI 93.6 to 97.8%) at 19 years. This study demonstrates an excellent long-term survival of the Spotorno CLS femoral component after 16 to 20 years in young patients undergoing total hip arthroplasty.

The Cementless Spotorno stem in THA: 10 year results

BACKGROUND

The clinical results of total hip arthroplasty (THA) with a cementless prosthesis have been constantly improving due to progress in the area of stem design and surface finish. Cementless Spotorno stem (CLS stem; Zimmer, Warsaw, USA) is a double-tapered rectangular straight stem. The purpose of this study is to investigate the mean 10 year results of CLS stem and to evaluate the press-fit stability of CLS stem.

METHODS

One hundred and eighty-six consecutive patients (194 hips) were evaluated at more than five years after THA using CLS stems. The mean follow-up period was 111 months. The radiographic stability of the femoral stem was determined by Engh's criteria. The ascertained period of spot welds was noted by Gruen zones on the femoral side. The presence of stress shielding, and subsidence was also evaluated.

RESULTS

A stable stem with bony on growth was identified in all cases. The mean period of expression of spot welds was 10.8 months in zone 2, 9.9 months in zone 3, 8.5 months in zone 5, and 8.8 months in zone 6. Stress shielding of more than grade 2 was observed in only three hips, which was non-progressive at one year after surgery. Subsidence of more than 2 mm was not observed in any of the hips.

CONCLUSIONS

Excellent stability of CLS stem has been maintained without abnormal bone reaction at the proximal femur. CLS stem is considered to achieve not only press-fit stability at trochanteric and subtrochanteric level, but bony fixation by osseointegration within one year after THA.

Cementless total hip arthroplasty with large diameter metal-on-metal heads: short-term survivorship of 8059 hips from the Finnish Arthroplasty Register

BACKGROUND AND AIMS

Population-based register data from the National Joint Register of Australia and England and Wales have revealed that the mid-term outcome of cementless large diameter head metal-on-metal total hip arthroplasty is inferior to that of conventional cemented metal-on-polyethylene total hip arthroplasty. The aim of this study was to compare the results of cementless large diameter head metal-on-metal total hip arthroplasty with conventional cemented arthroplasty in Finland. The second aim of this study was to compare the cementless large diameter head metal-on-metal models with each other.

MATERIAL AND METHODS

Based on the data extracted from the Finnish Arthroplasty Register, the risk of revision of 8059 cementless large diameter head metal-on-metal total hip arthroplasties performed during 2002-2009 was analyzed using Cox regression model. The revision risk of these hips was compared to that of 16,978 cemented metal-on-polyethylene total hip arthroplasties performed during the same time period.

RESULTS

In the Cox regression analysis, there was no difference in revision risks between cementless large diameter head metal-on-metal total hip arthroplasty and cemented metal-on-polyethylene total hip arthroplasty (relative risk = 0.90, confidence interval = 0.74-1.10, p = 0.3). However, in female patients aged 55 years or above, cementless large diameter head metal-on-metal total hip replacements showed a significantly increased risk of revision as compared to cemented total hip replacements (relative risk = 1.33, confidence interval = 1.04-1.70). Compared to the reference implant in this study (cementless Synergy stem combined with Birmingham Hip Resurfacing [BHR] cup), the CementLess Spotorno (CLS) stem combined with Durom cup had a 2.9-fold (95% confidence interval = 1.17-6.90) increased risk of revision.

CONCLUSIONS

We found that cementless large diameter head metal-on-metal total hip arthroplasty had short-term survivorship compared with cemented total hip arthroplasty at a nation-wide level. However, in female patients aged 55 years or above, cementless large diameter head metal-on-metal total hip arthroplasty showed inferior results. Furthermore, implant design had an influence on revision rates. Longer follow-up time is needed to assess the success of large diameter head metal-on-metal total hip arthroplasty.

Effects of micro-arc oxidation coating on outcomes of a cementless grit-blasted tapered-wedge stem in total hip arthroplasty

To evaluate the effects of micro-arc oxidation (MAO) coating on the outcomes of a grit-blasted tapered-wedge stem in total hip arthroplasty (THA), we performed a retrospective review of 141 THAs using MAO coated stem for a minimum of 5years and compared them to 219 THAs using the same geometry stem without MAO coating. Harris hip score improved from 43.7 points preoperatively to 93.9 points postoperatively. No hips were revised for aseptic loosening. Complications included one squeaking hip, one iliopsoas tendonitis, and one deep vein thrombosis. Postoperative Harris hip scores, WOMAC scores, UCLA activity scores, stem stabilities, and complication rates did not differ between the groups. After medium-term follow-up, our findings did not support the use of MAO coating on grit-blasted tapered-wedge stem to improve clinical outcomes.

Performance of the CLS Spotorno uncemented stem in the third decade after implantation

In 2012 we reviewed a consecutive series of 92 uncemented THRs performed between 1986 and 1991 at our institution using the CLS Spotorno stem, in order to assess clinical outcome and radiographic data at a minimum of 21 years. The series comprised 92 patients with a mean age at surgery of 59.6 years (39 to 77) (M:F 43;49). At the time of this review, seven (7.6%) patients had died and two (2.2%) were lost to follow-up. The 23-year Kaplan-Meier survival rates were 91.5% (95% confidence intervals (CI) 85.4% to 97.6%; 55 hips at risk) and 80.3% (95% CI, 71.8% to 88.7%; 48 hips at risk) respectively, with revision of the femoral stem or of any component as endpoints. At the time of this review, 76 patients without stem revision were assessed clinically and radiologically (mean follow-up 24.0 years (21.5 to 26.5)). For the 76 unrevised hips the mean Harris hip score was 87.1 (65 to 97). Femoral osteolysis was detected in five hips (6.6%) only in Gruen zone 7. Undersized stems were at higher risk of revision owing to aseptic loosening (p = 0.0003). Patients implanted with the stem in a varus position were at higher risk of femoral cortical hypertrophy and thigh pain (p = 0.0006 and p = 0.0007, respectively). In our study, survival, clinical outcome and radiographic data remained excellent in the third decade after implantation. Nonetheless, undersized stems were at higher risk of revision owing to aseptic loosening.

Estimated survival probability of the Spotorno total hip arthroplasty after a 15- to 21-year follow-up: one surgeon's results

We retrospectively assess 171 consecutive total hip arthroplasties (THAs) with a Spotorno CLS uncemented prosthesis implanted through a Hardinge approach. The mean follow-up was 17.9 years. All consecutive operations were performed by 1 surgeon. Eight patients had been lost to follow-up, and 77 had died for unrelated causes. Overall, 4 stems and 19 cups underwent revision. The cumulative survival rate at 21 years was 79.02% (95% confidence interval [95% CI], 45.98-100.00%) for the acetabular component and 96.71% (95% CI, 60.71-100.00%) for the stem. We can conclude that failure of the Spotorno CLS THA is mainly due to its acetabular component (relative risk 4.5). Survival results for the Spotorno CLS stem exceed the patients? life expectancies in the 60- to 70-year-old population in our area. Loosening with or without fatigue fracture of the component and the learning curve for proper implantation have been the main causes for the expansion cup failure.

Prospective five-year subsidence analysis of a cementless fully hydroxyapatite-coated femoral hip arthroplasty component

Early subsidence >1.5 mm is considered to be a predictive factor for later aseptic loosening of the femoral component following total hip arthroplasty (THA). The aim of this study was to assess five-year subsidence rates of the cementless hydroxyapatite-coated twinSys stem (Mathys Ltd., Bettlach, Switzerland).This prospective single-surgeon series examined consecutive patients receiving a twinSys stem at Maria Middelares Hospital, Belgium. Patients aged >85 years or unable to come to follow-up were excluded. Subsidence was assessed using Ein Bild Roentgen Analyse--Femoral Component Analysis (EBRA-FCA). Additional clinical and radiographic assessments were performed. Follow-ups were prospectively scheduled at two, five, 12, 24, and 60 months.In total, 218 THA (211 patients) were included. At five years, mean subsidence was 0.66 mm (95% CI: 0.43-0.90). Of the 211 patients, 95.2% had an excellent or good Harris Hip Score. There were few radiological changes. Kaplan-Meier analysis indicated five-year stem survival to be 98.4% (95% CI: 97.6-100%).Subsidence levels of the twinSys femoral stem throughout the five years of follow-up were substantially lower than the 1.5 mm level predictive of aseptic loosening. This was reflected in the high five-year survival rate.

Cementless anatomic total hip femoral component with circumferential porous coating for hips with developmental dysplasia: a minimum ten-year follow-up period

Anatomic femoral components are optimized for primary osteoarthritis, and few long-term results for their use are available for developmental dysplasia of the hip (DDH). We reviewed 135 uncemented total hip arthroplasties in which an anatomic femoral component was used in 106 patients with DDH, excluding femurs with neck-shaft angles of >160° and femurs with anteversion of >50°. The mean age of patients at surgery was 49.4 years (range, 33-66 years), and the mean duration of follow-up was 13.5 years (range, 10-18 years). No osteoporotic femurs were included in our study group. Despite 18 acetabular revisions, no femoral component was removed for any reason. No femoral loosening was seen at the final follow-up examination. An anatomic femoral component with circumferential porous coating can produce good clinical and radiologic findings in young patients with good bone quality who have DDH without excessive femoral deformity.

Cemented femoral fixation

There is a North Atlantic divide, with cementless femoral stems being used more frequently in the USA and cemented stems being used more frequently in many countries in Europe. This is primarily because different cemented stems have been used on different sides of the Atlantic and the results of the cemented stems in the US have often been poor, whereas the results of the stems used in Europe have been good. In the National registers in Europe, cemented stems have tended to achieve better results than cementless.

Cite this article: Bone Joint J 2013;95-B, Supple A:51–2.

Long-term (20- to 25-year) results of an uncemented tapered titanium femoral component and factors affecting survivorship

BACKGROUND

Uncemented femoral components in primary total hip arthroplasty (THA) are commonly used today, but few studies have evaluated their survival into the third decade.

QUESTIONS/PURPOSES

We evaluated (1) survivorship using femoral revision for any reason as the end point; (2) survivorship using femoral revision for aseptic loosening as the end point; and (3) patient-related and surgical risk factors for aseptic stem loosening at a minimum 20-year followup with an uncemented tapered titanium stem.

METHODS

We reviewed the clinical and radiographic results of 354 THAs in 326 patients performed between January 1985 and December 1989 using an uncemented grit-blasted, tapered titanium femoral stem. Mean age at surgery was 57 years (range, 13-81 years). Kaplan-Meier survivorship analysis was used to estimate long-term survival. Minimum followup evaluation was 20 years (mean, 22 years; range, 20-25 years); at that time, 120 patients (127 hips) had died, and four patients (five hips) were lost to followup. Multivariate survival analysis using a Cox regression model was performed.

RESULTS

Survivorship at 22 years with revision of the femoral component for any reason as the end point was 86% (95% confidence interval [CI], 81%-90%). Survivorship for femoral revision for aseptic loosening as the end point was 93% at 22 years (95% CI, 90%-96%). Undersized stems (canal fill index≤80%) and stems in hips with cup revision were at higher risk for aseptic loosening (hazard ratio, 4.2 and 4.3, respectively). There was a high rate of acetabular revision in this series (38%), mostly related to smooth-threaded, cementless sockets.

CONCLUSIONS

Uncemented femoral fixation was reliable into the third decade. Age, male sex, and diagnosis were not associated with a higher risk of aseptic loosening.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Heterotopic ossification in portal sites following hip arthroscopy

Heterotopic ossification (HO) is a well-known condition that usually occurs after head trauma, burns and open surgical procedures, most commonly around the hip and elbow joints. It is a well-documented complication occurring after open hip surgery; however, there exists limited information regarding its prevalence and clinical importance following hip arthroscopy. We report a case of symptomatic HO formation in portal sites following arthroscopic rim decompression, femoroplasty and labral debridement that was successfully treated with arthroscopic removal.

Eleven-year results of the anatomic coated CFP stem in primary total hip arthroplasty

There is a paucity of intermediate term results relating to short stem prostheses. The current study represents the longest follow-up results of the CFP prosthesis to the authors' best knowledge. Between January 1999 and December 2000, all total hip arthroplasty patients (n = 149), treated with this anatomic neck preserving stem in the authors' institution were enrolled in this study. After a mean follow-up time period of 11.2 years 117 patients were available for the follow-up examination. The mean HHS increased from 53 to 93. Overall, revision surgery was required in 11 patients (9.4%), with implant-associated complications noted in only five cases (4.3%). Aseptic loosening leading to implant removal was noted in four patients (3.4%). The current study's data suggest that the CFP implant, used in young patients undergoing primary total hip arthroplasty, is safe and provides excellent results after 11 years.

Total hip arthroplasty using cementless grit-blasted femoral component: a minimum 10-year follow-up study

The grit-blasted cementless Spotorno (CLS) stem, which has excellent survival rates up to 10 years, is widely used in total hip arthroplasty (THA). We investigated the survivorships of CLS stems in THA at a minimum follow-up of 10 years and sought to identify factors that influence outcomes. A total of 227 hips of 191 patients who underwent cementless THA with a CLS stem were retrospectively reviewed at a mean follow-up of 12.3 years. All patients were evaluated clinically and radiographically according to implant type and surgery-related and patient-related factors. Survivorship was 97.2% when femoral revision for any reason was defined as the end point. Femoral revisions were performed in 3 hips because of periprosthetic fractures. Survivorship for all hips, using revision for any reason as the end point, was 92.6%. Two metal-on-metal THAs were revised because of aseptic loosening or osteolysis around the cup. No significant differences were evident for type of stem, type of bearing surface, stem alignment, or patient-related factors. However, a canal fill index of 80% or less was found to affect cortical remodeling, subsidence, and a change in stem position of 5° or more, which indicates that care must be taken not to undersize stems. In addition, in view of the revisions performed, bearing surfaces appear to importantly influence THA survivorship.

Stress-related femoral cortical and cancellous bone density loss after collum femoris preserving uncemented total hip arthroplasty: a prospective 7-year follow-up with quantitative computed tomography

PURPOSE

Bone loss around uncemented femoral components is suspected to precede implant loosening and contribute to problems in revision surgery. Short-stemmed cementless femoral components are designed to preserve proximal femoral bone stock and ultimately the longevity of the prosthesis.

METHODS

With quantitative computed tomography-assisted osteodensitometry, we prospectively analyzed femoral cortical and cancellous bone density (BD) and contact area changes of an uncemented collum femoris preserving stem (n = 38) 10 days, 1, 3 and 7 years post-operatively.

RESULTS

Seven years post-operatively, cancellous BD (mg CaHA/mL) had decreased by as much as -66 % and cortical BD by up to -27 % at the metaphyseal portion of the femur; the decrease was progressive between the 1- and 3-year examinations and halted thereafter. Contact area (in % out of a possible 100 %) decreased proximally between the 1- and 3-year follow-up.

CONCLUSION

Proximal cortical and cancellous bone density loss and decrease of contact area indicate that metaphyseal fixation cannot be achieved. The lack of cortical BD loss and increase of contact area values below the trochanter minor suggest diaphyseal fixation.

[Periprosthetic femoral bone reaction after total hip arthroplasty with preservation of the collum femoris : CT-assisted osteodensitometry 1 and 3 years postoperatively]

BACKGROUND

Short-stemmed cementless femoral components in total hip arthroplasty have been designed to preserve the proximal femoral bone stock by load transfer to the femoral metaphysis. An in vivo method of computed tomography-assisted (CT) osteodensitometry after total hip arthroplasty is presented which differentiates between cortical and cancellous bone density (BD) changes around uncemented femoral components.

PATIENTS AND METHODS

Cortical and cancellous periprosthetic femoral BD (mg Ca HA/ml) was determined prospectively in 31 patients at day 10, 1 year and 3 years after total hip arthroplasty with preservation of the collum femoris (C.F.P.-stem, Link, Hamburg, Germany) using computed tomography-assisted osteodensitometry. Clinical results (Harris hip score) and plain x-rays were assessed in all cases.

RESULTS

Progressive proximal cortical BD loss was observed between the 1 year (Ø -8%) and 3 year (Ø -22%) postoperative measurements. Distal to the trochanter minor no significant cortical BD changes were observed. Proximal cancellous BD decreased progressively between the 1 year (Ø -33%) and 3 year (Ø -45%) analyses. The Harris hip score improved from 45 points pre-operatively to 93 points at the 3 year follow-up. All x-rays showed signs of stable ingrowth.

CONCLUSION

Periprosthetic CT osteodensitometry has the technical ability to discriminate between cortical and cancellous bone structures with respect to strain-adapted remodeling. Progressive proximal cortical and cancellous BD loss indicates that metaphyseal fixation cannot be achieved with the analyzed C.F.P. stem design. The lack of cortical BD loss below the trochanter minor suggests diaphyseal fixation of the implanted stem.

17-year follow-up of the rough-blasted threaded Weill cup in uncemented total hip arthroplasty

INTRODUCTION

For uncemented hip arthroplasty, various cup designs are available. The threaded Weill acetabular component (Weill cup; Zimmer, Winterthur, Switzerland) has been used for more than 20 years, with poor results of the smooth threaded design. Our study was intended to assess the 17-year outcome of the rough-blasted option of the threaded Weill cup.

MATERIALS AND METHODS

Between 1987 and 1988, a series of 86 rough-blasted threaded Weill cups were implanted in combination with the CLS Spotorno stem (Zimmer Ltd, Germany) The patients' mean age at the time of surgery was 50 years (range 19-67 years). 67 out of 86 hips (78%) were available for a follow-up at a mean of 17 years (range 16-18 years). Radiographs were available from 55 out of 63 unrevised hips (87%) and analyzed for radiolucency and PE wear.

RESULTS

Two out of 86 cups (3%) were revised due to aseptic loosening and another two cups (3%) were awaiting revision for the same reason. Ten patients (10 cups, 12%) were lost to follow-up, and nine patients with nine cups (11%) had deceased without radiographic signs of cup failure. Cup survival with "revision or awaiting revision" as endpoint was 86% (95% CI 75-92%). No deep infections occurred, and no polyethylene insert was exchanged. The Harris hip score was excellent in 37 out of 67 clinically examined hips (55%), good in 18 hips (26%), satisfactory in 5 hips (8%) and moderate or poor in 5 hips (8%) and 2 hips (3%), respectively.

CONCLUSION

The rough-blasted threaded Weill cup provides a good long-term performance in cementless total hip arthroplasty. The results compare favourably to the smooth threaded cup design.

Combined arthroscopic and radiation synovectomy of the knee joint in rheumatoid arthritis: 14-year follow-up

PURPOSE

To investigate the long-term outcome of combined arthroscopic and radiation synovectomy of the knee joint in early cases of rheumatoid arthritis (RA) with regard to knee function and the need for surgical re-interventions.

METHODS

Between 1993 and 1997, a consecutive series of 38 RA patients with therapy-refractory synovitis of the knee joint and only mild cartilage lesions (not exceeding Outerbridge grade II at surgery) were treated with combined arthroscopic and radiation synovectomy. Knee function was assessed preoperatively; at 6 months, 1 year, and 5 years; and finally, at a mean of 14 years with 4 different functional scores. A Kaplan-Meier survival curve was calculated with "any re-intervention" and "total knee arthroplasty" as endpoints.

RESULTS

Of 38 knees, 32 were available for the final 14-year follow-up with a total of 22 re-interventions: intra-articular steroid injection (n = 3), arthroscopic (n = 2) or radiation (n = 1) re-synovectomy, and total knee arthroplasty (n = 16). The remaining 10 patients with no re-intervention showed knee function not significantly different from the postoperative state. With any surgical re-intervention as the endpoint, the survival rate was 84% at 5 years (95% confidence interval [CI], 67.0% to 86.7%), 44% at 10 years (95% CI, 26.7% to 60.0%), and 32% at the 14-year assessment (95% CI, 16.0% to 49.3%). With total knee arthroplasty as the endpoint, the joint survival rate was 88.5% at 5 years (95% CI, 68.5% to 96.2%), 53.9% at 10 years (95% CI, 33.3% to 71.6%), and 39.6% at 14 years (95% CI, 18.9% to 48.6%).

CONCLUSIONS

Combined arthroscopic and radiation synovectomy leads to a stable improvement of knee function for a minimum of 5 years, but surgical re-interventions were frequently observed at the 14-year assessment and challenge the long-term benefit of the procedure. Patients with no interventions had a significantly shorter history of disease (7 v 11 years).

LEVEL OF EVIDENCE

Level IV, therapeutic case series.