Cementless total hip arthroplasty with a tapered, rectangular titanium stem and a threaded cup: a minimum ten-year follow-up

Functional assessment of component positioning in patients with groin pain after total hip arthroplasty as a tool to guide management

BACKGROUND

Persisting groin pain post total hip arthroplasty (THA) is a common and complex issue that can be difficult to diagnose and manage. Acetabular component positioning is often implicated.

AIMS AND METHODS

We used a previously well described and validated functional positioning protocol to determine if functional acetabular malpositioning was a factor in groin pain post THA and hence to determine if acetabular revision would be indicated. We compared patient-specific functional acetabular positioning to traditional CT evaluation of cup position and assessment of anterior cup overhang.

RESULTS

39 patients with groin pain post-THA were investigated. Functional acetabular malpositioning was diagnosed in 31% (12/39). Revision THA was performed in those 12 patients, resulting in resolution of functional malpositioning (100%), with an overall accuracy of 5.6° (range 1-12), and resolution of groin pain in 67% (8/12). 33% (4/12) of the revised implants had functional positioning located outside the traditional "40/20 zone". Comparison with CT indicated that 40% (4/10) of implants with anterior overhang were well positioned, however only 50% (6/12) of functionally malpositioned implants had CT evidence of anterior cup prominence. Of the 8/12 revision patients who had resolution of their groin pain, only 1 had cup prominence.

CONCLUSIONS

This study suggests that the utilisation of a patient specific functional positioning algorithm in the analysis of persistent groin pain following THA can assist in identifying the underlying cause of pain and help to guide treatment. For a functionally malpositioned acetabulum, revision surgery offers a potential resolution of groin pain.

Thirty-Year Minimum Follow-Up Outcome of a Straight Cementless Rectangular Stem

BACKGROUND

Meta-diaphyseal fixation of straight, tapered, uncemented stems has been proven to be very reliable for total hip arthroplasty in 10 to 20 years of follow-up studies. The aim of the study was to evaluate whether the implant survival as well as radiological and functional outcome have changed in patients with a minimum follow-up of 30 years.

METHODS

From a total of 210 patients, who received a straight, rectangular, tapered cementless stem and a threaded cup, there were 37 total hip arthroplasties (33 patients) still available for follow-up after a minimum of 30 years. Patients were examined clinically and radiographically, and revision surgeries were recorded.

RESULTS

There was a low rate of revisions of the femoral stem with a survival probability of 0.92 (confidence interval 0.85 to 0.96) at 30 years. Survival probability of the acetabular component decreased drastically with 0.45 (confidence interval 0.30 to 0.59). Radiographic analysis of the stem revealed radiolucencies in 73% (n = 16), but only in the proximal/metaphyseal part and none of the stems were radiographically loose.

CONCLUSION

In this minimum 30-year follow-up study, a straight rectangular cementless implant continues to provide excellent implant survival and high patient satisfaction. However, survival rates of the whole total hip replacement system were reduced by a high revision rate due to wear-related problems.

Influence of different CCD angles on osseointegration and radiological changes after total hip arthroplasty of a triple wedge shape cementless femoral stem: a prospective cohort study

PURPOSE

The purpose of this study was to evaluate the osseointegration and radiological outcomes in patients after total hip arthroplasty, hypothesizing different load patterns with one cementless stem design and different CCD angles (CLS Spotorno femoral stem 125° vs 135°).

METHODS

All cases of degenerative hip osteoarthritis fulfilling strict inclusion criteria were treated with cementless hip arthroplasty between 2008 and 2017. Ninety-two out of one hundred six cases were clinically and radiologically examined three and 12 months after implantation. Two groups with each 46 patients were rendered prospectively and compared in clinical (Harris Hip Score) and radiological outcome.

RESULTS

At final follow-up, no significant difference regarding Harris Hip Score was detected between the two groups (mean 99.2 ± 3.7 vs. 99.3 ± 2.5; p = 0.73). Cortical hypertrophy was found in none of the patients. Stress shielding was seen in a total of 52 hips (n = 27 vs. n = 25; 57% of the 92 hips). No significant difference regarding stress shielding was detected when comparing both groups (p = 0.67). Significant bone density loss was detected in Gruen zone one and two in the 125° group. The 135° group showed significant radiolucency in Gruen zone seven. No overall radiological loosening or subsidence of the femoral component was observed.

CONCLUSION

According to our results, the use of a femoral component with a 125° CCD angle versus a 135° CCD did not result in a different osseointegration and load transfer with a clinically relevant significance.

5-Year Clinical and Radiographic Results of the Direct Anterior Approach for Total Hip Arthroplasty Using a Collared Cementless Femoral Short-Stem Prosthesis

The aim of this study was to investigate the radiological and clinical outcome of the direct anterior approach (DAA) in total hip arthroplasty (THA) using a collared cementless femoral short-stem. This retrospective study included 124 patients with 135 THAs operated from 2014 to 2016 using a collared cementless triple tapered hydroxyapatite-coated femoral short-stem (AMIStem H Collared^®, Medacta International, Castel San Pietro, Switzerland) implanted with a DAA. Follow-up was performed at three months, 12 months, and five years. Clinical outcome was assessed using the hip osteoarthritis outcome score (HOOS) and radiological analysis was done using conventional radiographs, which included evaluation of the femur morphology based on Dorr classification, of radiolucencies based on the Gruen zone classification and of stem subsidence. The mean age was 67.7 ± 11.3 years and the mean body mass index (BMI) was 27.4 ± 4.4 kg/m². The stem survival rate at five years was 99.1% with one revision due to recurrent dislocations. Mean HOOS score improved from 40.9 ± 18.3 preoperatively to 81.5 ± 19.7 at three months, 89.3 ± 10.9 at 12 months, and 89.0 ± 14.0 at five years (all with p < 0.001). No significant correlations were found between age, femoral bone morphology, BMI and HOOS, and the appearance of relevant radiolucencies.

Long-term outcome of cementless total hip arthroplasty with threaded Tropic® acetabular cup and Corail® femoral stem

This study investigates the clinical and radiological results of a tapered femoral stem (Corail®) and uncemented threaded acetabular cups (Tropic®) and in addition an analysis of the complications and retrieved implants was conducted. Between January 1990 and September 1998, 301 total hips arthroplasties in 268 patients were implanted. 78 patients (87 hips) had died and 9 patients (12 hips) had been lost to follow-up, leaving at the time of the latest follow-up 180 patients (202 hips). The mean age at surgery was 56,1 (27-75) years. Of the 154 unrevised hips, the median Harris and Merle d´Aubigne and Postel hip scores were 83,3 points and 15,3 points respectively at the latest follow-up. The median follow-up time was 16.9 years (10,4-25). No femoral component was revised for aseptic loosening ; osteolysis was observed in the 9,5% of the implants (13 stems). 48 hips (23%) were revised and 27 cups (56,2%) needed revision surgery because of massive polyethylene wear. Pelvic osteolysis was found out in 80 cups (58,8%). 87 hips (63,9%) showed signs of a progressive wear of the liner, more than 2mm in 48 hips. Kaplan-Meier survivorship analysis at 15 years follow-up was 81.2% with revision for any reason (85.8% for mechanical or radiographic loosening). High rates of polyethylene wear and the high prevalence of pelvic osteolysis are serious matters in these types of implants with high rates of revision at 15 years follow-up so we decided to abandon the concept of a threaded cup design in favor of a press-fit acetabular cup.

A Prospective, Randomized Comparison of the Long-Term Clinical and Radiographic Results of an Ultra-Short vs a Conventional Length Cementless Anatomic Femoral Stem

BACKGROUND

The purpose of this study is to compare the long-term clinical and radiographic results, survival rates, and complication rates of an ultra-short vs a conventional length cementless anatomic femoral stem.

METHODS

We reviewed 759 patients (858 hips) (mean age, 56.3 ± 12.9 y) who had an ultra-short cementless anatomic stem and 759 patients (858 hips) (mean age, 54.8 ± 12.3 y) who had a conventional length cementless anatomic stem. The mean follow-up was 16.5 years (range 14-17) in the ultra-short stem group and 17.5 years (range 17-20) in the conventional stem group.

RESULTS

At the latest follow-up, there were no significant differences between the 2 groups in terms of the Harris Hip Scores (92 ± 6 vs 91 ± 7 points, P = .173), Western Ontario and McMaster Universities Osteoarthritis scores (12 ± 8 vs 13 ± 7 points, P = .972), University of California Los Angeles activity scores (7.6 vs 7.8 points, P = .841), patient satisfaction scores (7.7 ± 2.3 vs 7.5 ± 2.5 points, P = .981), and survival rates (97.6% vs 96.6%). However, incidence of thigh pain (P = .031) and stress shielding (P = .001) was significantly higher in the conventional length stem group than in the ultra-short anatomic stem group. Complication rates were similar (1.8% vs 2.7%) between the 2 groups.

CONCLUSION

Although an ultra-short cementless anatomic femoral stem confers equivalent clinical and radiographic outcomes, survival rates, and complication rates to conventional length cementless anatomic stem, the incidence of thigh pain and stress shielding was significantly lower in the ultra-short cementless anatomic stem.

LEVEL OF EVIDENCE

Therapeutic Level I.

Second-generation uncemented total hip arthroplasty: a minimum 20-year follow-up

Aims

We present the clinical and radiological results at a minimum follow-up of 20 years using a second-generation uncemented total hip arthroplasty (THA). These results are compared to our previously published results using a first-generation hip arthroplasty followed for 20 years.

Methods

A total of 62 uncemented THAs in 60 patients were performed between 1993 and 1994. The titanium femoral component used in all cases was a Taperloc with a reduced distal stem. The acetabular component was a fully porous coated threaded hemispheric titanium shell (T-Tap ST). The outcome of every femoral and acetabular component with regard to retention or revision was determined for all 62 THAs. Complete clinical follow-up at a minimum of 20 years was obtained on every living patient. Radiological follow-up was obtained on all but one.

Results

Two femoral components (3.2%) required revision. One stem was revised secondary to a periprosthetic fracture one year postoperatively and one was revised for late sepsis. No femoral component was revised for aseptic loosening. Six acetabular components had required revision, five for aseptic loosening. One additional acetabular component was revised for sepsis. Radiologically, all femoral components remained well fixed. One acetabular was judged loose by radiological criteria. The mean Harris Hip Score improved from 46 points (30 to 67) preoperatively to 89 points (78 to 100) at final follow-up. With revision for aseptic loosening as the endpoint, survival of the acetabular component was 95% (95% confidence interval (CI) 90 to 98) at 25 years. Femoral component survival was 100%.

Conclusion

The most significant finding of this report was the low prevalence of aseptic loosening and revision of the femoral component at a mean follow-up of 22 years. A second important finding was the survival of over 90% of the hemispheric threaded ring acetabular components. While these shells remain controversial, in this series they performed well.Cite this article: Bone Jt Open 2021;2(1):33-39.

Clinical and Radiological Results of Crowe Type 3 or 4 Dysplasia Patients Operated on With Total Hip Arthroplasty Using a Cementless Rectangular Femoral Component Without Fixating or Grafting the Transverse Osteotomy Site

BACKGROUND

Total hip arthroplasty (THA) involving shortening osteotomy for patients with Crowe type 3 or 4 dysplasia is a challenging surgical procedure. This study aims to demonstrate that rectangular femoral component use in anatomical reconstructions with THA and transverse shortening osteotomy yields successful results without the use of bone graft or any fixation material at the osteotomy site.

METHODS

Fifty hips from 41 patients were identified retrospectively as per study objectives. All patients were evaluated using the Harris Hip Score and Visual Analog Scale for pain. Complications were reported. Radiological evaluation criteria were then evaluated, including leg length discrepancy, degree of trochanter caudalization and stem subsidence, radiolucent and radiodense lines for both components and bone atrophy or hypertrophy around the stem according to Gruen zones, and the canal fill ratio of the stem.

RESULTS

Postoperative Harris Hip Score was excellent for 68% of patients. No patient had poor results. Complication rate was 32%. One patient had nonunion (2%). The mean postoperative leg length discrepancy was 0.8(±0.6) cm. No patient had a subsidence of more than 5 mm. Radiolucent and radiodense lines were present in up to 34% of patients, and bone atrophy was present in the proximal femur in up to 96% of patients. No patient had osteolysis or loosening in neither component.

CONCLUSION

Successful clinical and radiological results can be obtained from Crowe type 3 and 4 dysplastic hips operated on with THA using a rectangular femoral component and transverse shortening osteotomy technique. The use of graft or any fixation material at the osteotomy site is not mandatory.

High Revision Rates of a Cementless Beta-Titanium Alloy Stem with Contamination-Free Roughened Surface in Primary Total Hip Arthroplasty

Optimal osseointegration of cementless total hip arthroplasty is essential for high stability and long-term survival. The purpose of this follow-up study was to evaluate the clinical and radiological outcome, the complications, and survival rates of a beta-titanium alloy stem with a specific grit-blasted-free surface. In 192 patients (mean age of 64.4 years), 202 consecutive primary total hip arthroplasties were performed using a cementless Hipstar^® stem (Stryker, Duisburg, DE). The Harris Hip Score (HHS) was assessed pre-operatively and post-operatively. Radiolucent lines were evaluated and the implant survival rate was calculated using Kaplan-Meier analysis. The mean follow-up was 7.71 years (range of 5.0–14.0 years). Overall, 15 revisions were performed. Early aseptic stem loosening was observed in six cases (2.97%). Radiolucent-lines adjacent to the stem were detected in 73 cases (83.02%), especially (70.46%) in the Gruen zones 1, 7, 8, and 14. The mean postoperative HHS was 92.65 points (range 42–100). The cumulative survival probability of the stem was 94.4% (95% CI 90.3 to 98.5%). Considering aseptic failure as an endpoint, the cumulative survival rate of the stem was 95.3% (95% CI 0.914 to 0.992) at six years of follow-up. Overall, an inferior mid-term implant survival was observed in comparison to well-established cementless stem designs.

Comparison of early femoral bone remodeling and functional outcome after total hip arthroplasty using the SL-PLUS MIA stem with and without hydroxyapatite coating

BACKGROUND

Few reports have evaluated the use of hydroxyapatite (HA) coating in SL-MIA-type stems in total hip arthroplasty (THA). Here, we compared early femoral bone remodeling after total hip arthroplasty using the SL-PLUS MIA stem with and without hydroxyapatite coating.

METHODS

From February 2012 to March 2017, 132 patients (150 hips) (HA group: 48 patients [52 hips], non-HA group: 84 patients [98 hips]) underwent THA with an SL-PLUS MIA stem. The mean follow-up duration was 3.7 years (standard deviation 1.2, range: 1.0-6.1). The Harris Hip Score (HHS), postoperative bleeding volume measurements and plain radiographs were used for clinical and radiological follow-up evaluations. Peri-prosthetic bone mineral density changes were measured by dual-energy X-ray absorptiometry.

RESULTS

At 1 year, the HHS improved from 44.4 points preoperatively to 89.2 points postoperatively and from 44.5 points to 89.7 points in the HA and non-HA groups, respectively. At 1 year postoperatively, subsidence (≧ 3 mm) occurred in 0% and 8.2% of the HA and non-HA groups, respectively. Stress shielding (≧ Grade 3) occurred in 0% and 6% of the HA and non-HA groups, respectively. The radiolucent line was significantly smaller in the HA than in the non-HA group. There was no significant difference in the bone mineral density distribution in the two groups.

CONCLUSION

Addition of HA to the SL-MIA stem can help enhance the initial fixation and early osseointegration. Further studies are required on the long-term effects of adding HA to reduce stress shielding of the proximal area of the stem.

Aucubin suppresses Titanium particles‑mediated apoptosis of MC3T3‑E1 cells and facilitates osteogenesis by affecting the BMP2/Smads/RunX2 signaling pathway

Aucubin represents an iridoid glucoside separated from multiple Chinese herbs, which has been demonstrated to possess numerous pharmacological activities. In the present study, the aim was to investigate the roles and mechanisms of aucubin in the suppression of mouse MC3T3-E1 osteoblast apoptosis induced by Titanium particles and the promotion of bone formation. MTT assay and flow cytometry were performed to analyze cell viability and apoptosis, respectively. ELISA and para-nitrophenyl phosphate colorimetry were carried out to evaluate the oxidative stress markers and alkaline phosphatase (ALP). Western blotting and reverse transcription-quantitative polymerase chain reaction assays were used to evaluate the associated mRNA and protein expression. The results revealed that aucubin enhanced the cell activity of MC3T3-E1 cells treated with Ti particles. Aucubin suppressed the apoptosis of Ti particles-induced MC3T3-E1 cells and facilitated osteogenesis by affecting the B-cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein, ALP and associated osteogenic factors expression. Aucubin reduced the oxidative stress in Ti particles-induced MC3T3-E1 cells. In addition, aucubin upregulated the bone morphogenetic protein 2 (BMP2)/Smads/runt related transcription factor 2 (RunX2) pathway in Ti particles-induced MC3T3-E1 cells. In conclusion, the present study confirmed that aucubin suppressed the Ti particles-mediated apoptosis of MC3T3-E1 cells and facilitated osteogenesis by affecting the BMP2/Smads/RunX2 signaling pathway.

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.

Total Hip Arthroplasty with Use of the Cementless Zweymüller Alloclassic System: A Concise Follow-up, at a Minimum of 25 Years, of a Previous Report

We previously reported the 10 to 13-year follow-up results for 104 total hip replacements with the Zweymüller Alloclassic stem and a threaded cup in 94 patients. The present study is a clinical and radiographic outcome update after a minimum follow-up of 25 years. Four patients (4 hips) were lost and 46 patients (50 hips) died, leaving 44 patients (50 hips) available for follow-up. Since our previous report, 7 cups and 2 stems were revised. At 20 years, the probability of survival of any component was 84.1% (95% confidence interval [CI], 73.91% to 94.29%) and the cumulative probability of not having stem loosening was 95.9% (95% CI, 95.51% to 96.29%). We observed proximal femoral osteolysis in 15 hips (30%), cortical hypertrophy in 21 hips (42%), and proximal femoral osteopenia in 30 hips (60%). The Zweymüller Alloclassic stem continues to provide excellent results after extended follow-up.

LEVEL OF EVIDENCE

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

19 years outcome after cementless total hip arthroplasty with spongy metal structured implants in patients younger than 65 years

Background

Cementless fixation of total hip arthroplasties (THAs) is often favored in young, high-demanding patients due to the conservation of valuable bone-stock and easier revision if loosening has occurred. Long-term outcome data of the spongy metal structured implant used in the present study in patients younger than 65 years are still lacking.

Methods

We conducted a retrospective chart review and functional investigation (Merle d’Aubigné score, SF-12) of patients younger than 65 years at implantation treated with a spongy metal structured THA (n = 79) from one orthopedic university center from 1985 to 1989.

Results

At a 19-year mean follow-up (range: 15.3 – 21.3 years), the overall stem survival rate was 93.7 %, and the overall cup survival rate was 82.3 %. Revision surgeries of the stem were performed in all cases for aseptic loosening at an average of 15.3 ± 3.5 years after implantation. Acetabular components were revised for aseptic loosening and recurrent dislocation after inlay revision on an average of 11.8 ± 4.7 years after implantation. No other device related complications occurred within the 19-year follow-up period. No correlation was found between time of revision and gender or age. Clinical outcome scores (Merle d’Aubigné score, SF-12) revealed excellent to good results of the implanted THAs in 87 % of patients.

Conclusions

We conclude that spongy metal structured cementless THAs implanted in young patients have an excellent survival and provide trustworthy clinical results at 19 years of follow-up.

Ultrashort versus Conventional Anatomic Cementless Femoral Stems in the Same Patients Younger Than 55 Years

BACKGROUND

Because the clinical and radiographic performance of an ultrashort anatomic cementless stem has been investigated in only two randomized controlled studies, well-designed trials should aim for a thorough comparison of the outcomes of ultrashort anatomic cementless and conventional anatomic cementless stems.

QUESTIONS/PURPOSES

The purposes of this study were to compare (1) the clinical results, including Harris hip score, thigh pain, and WOMAC index score, (2) radiographic results, (3) bone mineral density; and (4) proportions of patients undergoing revision of a THA using an ultrashort anatomic cementless stem versus a conventional anatomic cementless stem in the same patients who underwent bilateral sequential THAs under the same anesthetic.

METHODS

Two hundred patients (mean age, 53 years; range, 26-54 years) who underwent bilateral sequential THAs received an ultrashort anatomic cementless stem in one hip and a conventional anatomic cementless stem in the contralateral hip. From January 2004 to December 2005, we performed 524 same-day bilateral short and conventional anatomic cementless THAs in 262 patients, of whom 212 (81%) participated in this study. Five patients were lost to followup before 2 years, five were lost between 2 to 10 years, and two were lost between 10 to 13 years, leaving 200 patients. Patients who had end-stage bilateral hip disease and were younger than 55 years were selected for inclusion. The predominant diagnoses were osteonecrosis (118 patients, 59%) and osteoarthritis (44 patients, 22%). One hundred thirty-eight were men and 62 were women. At the time of each followup, the patients were assessed clinically and radiographically. In addition, each patient completed the WOMAC and the University of California Los Angeles (UCLA) activity scores. The minimum followup was 10 years (mean, 11.8 years; range, 10-13 years). Followups were done in person, with all images and followup clinic notes. Based on the power analysis, we estimated a sample size of 178 hips was needed in each group to detect a 3-point difference in the Harris hip score with 80% power.

RESULTS

At the latest followup, there were no differences between the two groups regarding the mean Harris hip scores (94 versus 94 points; p = 0.189), mean WOMAC scores (17 versus 16 points; p = 0.191), or mean UCLA activity scores (9 versus 9 points; p = 0.381). Two patients in the ultrashort stem group and one patient in the conventional stem group had severe (9 points) thigh pain, and 30 patients (15%) in the conventional stem group had mild thigh pain (2 or 3 points) after vigorous exercise. Bone mineral density in the ultrashort and conventional stem groups, respectively, was greater in the ultrashort stem group than in the conventional stem group. Bone mineral density in Zone 1 at 12 years was 3.29 versus 1.88 g/cm(2) (p = 0.021), and 2.97 versus 0.91 g/m(2) in Zone 7 (p = 0.001). With the numbers available, there were no differences between the stem designs in terms of the proportion undergoing revision (one hip, 0.5%, in the short-stem group versus one hip, 0.5%, in the conventional group; p = 1.881).

CONCLUSIONS

At followup into the second decade, ultrashort stems showed no differences from conventional cementless stems in terms of validated outcomes scores or fixation, although less stress shielding was observed. Reduction of stress shielding may reduce the long-term risk of periprosthetic fracture, but this was not shown in our study.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Stable Fixation of a Cementless, Proximally Coated, Double Wedged, Double Tapered Femoral Stem in Total Hip Arthroplasty: A 5-Year Radiostereometric Analysis

BACKGROUND

The objective of this 5-year prospective study of 51 hips was to assess migration of a cementless tapered femoral stem using radiostereometric analysis (RSA), plain radiographs (radiolucencies), and patient-reported outcome measures (PROMs).

METHODS

Forty-seven patients (51 hips) agreed to participate in this prospective RSA study. All patients received a Taperloc stem. Tantalum beads were inserted into the femoral bone surrounding the stem to measure migration using RSA. RSA films, plain radiograph, and PROM follow-up were obtained immediately after surgery, 6 months, 1, 2, 3, and 5 years after surgery.

RESULTS

The median (interquartile range) subsidence was 0.03 mm (-0.23 to 0.06) at 5 years, with no significant differences over time. Four outlier stems had >1.5 mm of subsidence by 1 year. No stem showed radiolucencies in more than 3 zones during the 5 years. All PROMs remained favorable at 5 years, suggesting an excellent outcome. There were no stems revised for mechanical loosening; 1 stem was revised for an infection.

CONCLUSION

After initial settling, the cementless tapered femoral stems in our series were stable. The 4 outlier stems with >1.5 mm of subsidence by 1 year remain stable at 5 years. RSA was the most sensitive method of detection for stems at greater risk for potential future failure. This report adds contributions to the positive results associated with this type of fixation. The results at 5 years showed excellent midterm survivorship in this cohort with a cementless tapered femoral component.

Outcome of the Cementless Zweymüller BICON-PLUS Cup and SL-PLUS Stem in the Very Elderly Individuals

Introduction:

There is current debate about which type of total hip prosthesis implants are best for the elderly patient. Implanting uncemented total hip arthroplasty (THA) in elderly people remains contested. The aim of present study was to evaluate the outcome of the uncemented Zweymüller BICON-PLUS THA in those with a minimum of 80 years of age.

Materials and Methods:

A retrospective data collection was performed in a regional teaching hospital in the Netherlands. The primary outcome of interest was the operation-free period. Secondary outcomes included the revision rates of the femoral and acetabular components and postoperative complications of the procedure. After a follow-up of at least 7 years, the surviving patients were reviewed on functionality using validated scores (Hip Disability and Osteoarthritis Outcome Score, Timed Up and Go, and Harris Hip Score) and radiographic analysis.

Results:

Between January 1999 and September 2004, 124 patients (128 THAs), aged 80 years and older, received an uncemented THA with a BICON-PLUS cup and SL-PLUS stem. The overall operation-free period was 6.5 years. One case of loosening of the cup was found among participants, with a survival rate of 99.2% of the BICON-PLUS cup in the analyzed group. In all, 28.8% of this group could be followed for a postoperative period of at least 7 years. The remainder of the patients died prior to the end of the 7-year period. Of these, 16.0% were eligible for clinical review. This group showed good function without evident signs of prosthetic loosening.

Conclusion:

The uncemented Zweymüller THA system, with threaded BICON-PLUS cup and SL-PLUS stem, showed good results, compared to outcome of other THA systems in elderly individuals. Therefore, it is a reliable option in older patients requiring THA.

The Corail® stem for the treatment of displaced femoral neck fractures - a viable alternative

Cementless hemiarthroplasty in hip fracture surgery has been associated with poorer outcomes and more pain than cemented hemiarthroplasty. The aim was to investigate clinical and radiographic outcomes for a cementless tapered titanium fully hydroyxapatite-coated (Corail® System) stem in this consecutive cohort of hip fracture patients. We retrospectively evaluated the results of 68 consecutive elderly patients with displaced intracapsular hip fractures, treated with this implant. Mean clinical follow-up was 4.3 years (2-6 years). One-year mortality was 24%. 95% of patients had no/occasional/mild mid-thigh pain, with moderate pain in 5%. 39% achieved independent or walking-stick mobility. 36 patients had follow-up radiography. Osseointegration was noted in 34, with a mixed bony/fibrous in-growth in 2. One patient had revision for subsidence of an undersized implant, with no conversions to total hip arthroplasty. The Corail® stem can be used effectively for the treatment of femoral neck fractures in the elderly.

A Cannulated Tri-Tapered Femoral Stem for Total Hip Arthroplasty: Clinical and Radiological Results at Ten Years

We report the ten-year clinical and radiological outcomes of a novel cannulated, tri-tapered femoral stem, used in primary total hip arthroplasty (110 stems in 98 patients). At ten years, two Tri-taper stems had been revised for infection and dislocation. The mean Oxford Hip Score improved from 13.46 pre-operatively, to 37.04. Radiological analysis revealed radiolucent lines in 57 cases, but none exceeded 2 mm thickness. Stem subsidence was identified in 63 cases, with mean distal tip migration of 3.8 mm. Survivorship with revision for aseptic loosening as the end point was 100% at 10 years. Stem survival with revision for any cause was 98.2% (95% CI, 92.9% to 99.5%). The ten-year results of the Tri-taper stem are comparable to other polished, tapered femoral stems.

[The spectrum of histomorphological findings related to joint endoprosthetics]

Approximately 230,000 total hip and 170,000 knee joint endoprostheses are implanted in Germany annually of which approximately 10% (i.e. 40,000 interventions per year) are cases of revision surgery. These interventions involve removal of a previously implanted prosthesis which has resulted in complaints and replacement with a new prosthesis. There are manifold reasons for revision surgery, the most common indication being so-called endoprosthesis loosening, which is subdivided into septic and aseptic loosening. Histomorphological studies revealed that periprosthetic tissue from endoprosthesis loosening can be classified into four types (I) wear-particle induced type, (II) infectious type, (III) combined type and (IV) fibrous type. Types I and IV represent aseptic loosening and types II and III septic loosening. Recently, the topic of implant allergy has emerged. The detection of cellular, mostly perivascular lymphocytic infiltrates is discussed as being a sign of an allergic tissue reaction. It has most frequently been observed in type I periprosthetic membranes with a dense load of metal wear, which occurs with metal-on-metal bearings. Apart from endoprosthesis loosening, arthrofibrosis is another complication of joint endoprosthetics and can cause pain and impaired function. Histopathologically, arthrofibrosis can be evaluated by a three-tiered grading system. Furthermore, bone pathologies, such as ossification, osteopenia or osteomyelitis can occur as complications of joint endoprosthetics. This review gives an overview of the whole spectrum of pathological findings in joint endoprosthetics and offers a comprehensive and standardized classification system for routine histopathological diagnostics.

Long-term follow-up of primary total hip arthroplasty with the Alloclassic Variall system

PURPOSE

The aim of the present study was to evaluate the clinical and radiographic results of primary total hip arthroplasty (THA) performed with the Alloclassic Variall system (a modified version of the Alloclassic Zweymüller system) and to compare them with those in the literature for the original system.

METHODS

Between January 2001 and December 2002, 273 consecutive primary THAs were performed in 259 patients at a single centre with the study system, using ceramic-on-ceramic (81.7 %) or ceramic-on-highly-crosslinked-polyethylene (18.3 %) articulations.

RESULTS

At the time of this study, 28 patients (29 hips; 10.6 %) had died and 40 (43 hips; 15.8 %) were lost to follow-up. Seventeen patients (19 hips; 7.0 %) could be reached only by telephone. There were four revisions in four patients (1.5 %), all involving only the femoral component. Ten-year Kaplan-Meier survival with revision of any component for any reason as the endpoint was 98.4 % (95 % confidence interval: 96.9-100 %; 30 hips remained 'at risk'). A total of 170 unrevised patients (178 hips; 65.2 %) were assessed clinically and radiographically at a median follow-up of 9.3 years (interquartile range [IQR] 8.8-9.8 years). The median Harris hip score (HHS) was 99.9 points (IQR 97.7-100). The score did not differ significantly between the two articulations. There was no sign of radiographic loosening.

CONCLUSIONS

The ten-year implant survival and the HHS score outcomes for THAs performed with the novel system were in line with those documented in the literature for its predecessor.

Ten to fifteen-year clinical and radiographic follow-up with a third-generation cementless stem in a young patient population

PURPOSE

Outcome data beyond 11 years of follow-up is not available for the third-generation Zweymüller femoral stem in combination with a polyethylene bearing. We report ten to 15-year results with this total hip arthroplasty (THA) combination in a young population.

METHODS

A retrospective, observational, non-randomised, single-centre, clinical observational study was conducted in which 311 primary THAs were performed in 276 patients between 1996 and 2000 using a third-generation Zweymüller stem. The mean age of the patients at operation was 47.4 years (range 18-77 years).

RESULTS

Stem survival for any reason was 93.5% after ten years and 89.6% after 13 years, and the probability of aseptic stem loosening was 98.7% at both ten and 13 years. The occurrence of femoral radiolucent lines was low, at just 17.2%. Minor femoral osteolysis was identified in 30% of patients and was attributed to polyethylene liner wear. Clinical and patient satisfaction outcomes were in line with previous investigations, and the rate of adverse events was low.

CONCLUSIONS

The third-generation Zweymüller stem shows good radiographic and clinical results and good longevity, including in the younger osteoarthritic patient. The use of low-wear bearings may further reduce the rate of osteolysis and wear-related revision in young and active patients.

The Early Result of Cementless Arthroplasty for Femur Neck Fracture in Elderly Patients with Severe Osteoporosis

Purpose

The purposes of the current study were to assess the early results of cementless hip arthroplasty (HA) for femoral neck fractures in elderly patients with severe osteoporosis and to compare the clinical outcomes between those who underwent total HA (THA) or bipolar hemiarthroplasty (BHA).

Materials and Methods

From April 2011 to May 2012, we performed 87 cementless HAs for displaced femoral neck fractures in elderly patients (≥65 years) with severe osteoporosis. Among them, we studied 70 hips that were able to be followed-up for >24 months. Of these, 34 underwent THA and 36 underwent BHA. Clinical results were evaluated using the Harris hip score (HHS), Koval classification, and radiographs.

Results

Only one instance of femoral stem loosening was observed. Additionally, no dislocations were observed and no revision surgeries were required. The mean changes in the functional items of the HHS scores were 2.8 and 5.2 for those who underwent THA and BHA, respectively (P<0.05). According to the Koval classification used for the ambulatory status analysis, the mean perioperative change in the grade was 0.8 (0-4), with no significant differences noted between the THA and BHA groups.

Conclusion

The early results of cementless HA for femur neck fractures in elderly patients with osteoporosis were satisfactory, and THA was found to have a functional advantage over BHA.

A comparative assessment of small-head metal-on-metal and ceramic-on-polyethylene total hip replacement

Large-head metal-on-metal (MoM) total hip replacements (THR) have given rise to concern. Comparative studies of small-head MoM THRs over a longer follow-up period are lacking. Our objective was to compare the incidence of complications such as infection, dislocation, revision, adverse local tissue reactions, mortality and radiological and clinical outcomes in small-head (28 mm) MoM and ceramic-on-polyethylene (CoP) THRs up to 12 years post-operatively. A prospective cohort study included 3341 THRs in 2714 patients. The mean age was 69.1 years (range 24 to 98) and 1848 (55.3%) were performed in women, with a mean follow-up of 115 months (18 to 201). There were 883 MoM and 2458 CoP bearings. Crude incidence rates (cases/1000 person-years) were: infection 1.3 vs 0.8; dislocation 3.3 vs 3.1 and all-cause revision 4.3 vs 2.2, respectively. There was a significantly higher revision rate after ten years (adjusted hazard ratio 9.4; 95% CI 2.6 to 33.6) in the MoM group, and ten of 26 patients presented with an adverse local tissue reaction at revision. No differences in mortality, osteolysis or clinical outcome were seen. In conclusion, we found similar results for small-head MoM and CoP bearings up to ten years post-operatively, but after ten years MoM THRs had a higher risk of all-cause revision. Furthermore, the presence of an adverse response to metal debris seen in the small-head MOM group at revision is a cause for concern.

Comparison of total hip arthroplasty in osteoarthritis of mechanical and rheumatologic causes

Objective:

To compare the use of uncemented implants in total hip arthroplasty in patients with rheumathologic diseases and mechanical osteoarthrosis.

Methods:

We retrospectively evaluated 196 patients who were operated by the Hip and Arthroplasty Surgery Group of the IOT-HCFMUSP between 2005 and 2009. Patients were divided into two groups: mechanical causes (165 patients) and rheumathologic causes (31 patients). Groups were compared between each other in age, gender and follow-up time. Osseointegration rate and percentage of failure in arthroplasty were evaluated.

Results:

No statistically significant difference was found in osseointegration rates (in both femoral and acetabular components) in both groups. The rates of revision surgery and implant survival also did not show statistically significant differences.

Conclusion:

The use of uncemented total hip arthroplasty did not show worse results in rheumathologic patients. Level of Evidence III, Retrospective Case Control Study.

[Revised consensus classification. Histopathological classification of diseases associated with joint endoprostheses]

The revised classification of the periprosthetic membrane (synovial-like interface membrane SLIM) encompasses all pathological alterations which can occur as a result of endoprosthetic replacement of major joints and lead to a reduction in durability of prostheses. This also includes the established consensus classification of SLIM by which aseptic and septic prosthetic loosening can be subdivided into four histological types and histopathological criteria for additional pathologies: endoprosthesis-associated arthrofibrosis, immunological/allergic alterations and osseous pathologies. This revision represents the foundation for the histopathological diagnostics of the total spectrum of diseases associated with joint prostheses, is a suitable basis for a standardized diagnostic procedure and etiological clarification of endoprosthesis failure and also as a data standard for endprosthesis registers, in particular for registers based on routine data (e.g. German endoprosthesis register).

Fixation of non-cemented total hip arthroplasty femoral components in a simulated proximal bone defect model

An accelerated sequential proximal femoral bone loss model was used to measure the initial stability of three noncemented femoral stem designs: fully porous-coated, proximally porous-coated, and dual-tapered, diaphyseal press-fit (N=18). Only dual-tapered, diaphyseal press-fit stems remained stable with as much as 105 mm of bone loss, with average cyclic micromotion remaining below 25 μm in ML and below 10 μm in AP planes. In contrast, with proximally coated and fully coated stem designs with circular or oval cross-sections, 60mm of bone loss, resulting in lower than 10 cm of diaphyseal bone contact length, led to gross instability, increasing average cyclic micromotions to greater than 100 μm prior to failure. Therefore, the results provide support for using a dual-tapered stem in revision cases with proximal bone loss.

Effect of proximal femoral bone support on the fixation of a press-fit noncemented total hip replacement femoral component

PURPOSE

Proximal femoral bone loss is a common challenge in revision hip arthroplasty. In this study, in-vitro fixation of a non-cemented, rectangular, dual-tapered, press-fit femoral component designed to achieve metadiaphyseal fixation was analyzed using an accelerated proximal femoral bone loss model to assess the potential use in revision cases.

METHODS

The press-fit AlloclassicTM femoral stem was implanted in ten cadaveric femurs and tested under cyclic biomechanical loading in an intact state, and then again after sequential proximal femoral bone resections, simulating increasing amounts of bone deficiency. Anterior-posterior and medial-lateral interface motions were measured at the distal stem tip throughout loading. 


RESULTS

Three specimens remained stable throughout testing, with initial and peak per-cycle motions of less than 50 μm. Six specimens were destabilized under loading with higher per-cycle motions, specifically at the distal stem tip during peak loading in the anterior-posterior direction, with motions of 78±69 μm, compared to 12±9 μm in the stable specimens (P<.05). Total migration of the destabilized specimens was also significantly higher, specifically at the proximal stem tip in the medial-lateral direction, with migrations of 101±34 μm (P<.05) and at the distal stem tip in the anterior-posterior direction, with migrations of 155±179 μm (P<.05), compared to 33±12 μm and 13±11 μm for the stable specimens.

CONCLUSION

The results indicate that when strong initial fixation is achieved, long-term success is possible given substantial proximal femoral bone loss.

In vivo serum titanium ion levels following modular neck total hip arthroplasty--10 year results in 67 patients

The objective of the present cross-sectional study was to determine in vivo titanium ion levels following cementless total hip arthroplasty (THA) using a modular stem system with different shapes for femoral canal fit and multiple neck options. A consecutive series of 173 patients (190 hips) who underwent cementless modular neck THA and a ceramic on polyethylene bearing with a median follow-up of 9 (7-13) years was evaluated retrospectively. According to a standardized protocol, titanium ion measurements were performed on 67 patients using high-resolution inductively coupled plasma-mass spectrometry. Ion levels were compared to a control group comprising patients with non-modular titanium implants (n=11) and to individuals without implants (n=23). Modular neck THA did not result in elevated titanium ion levels compared to non-modular THA. Compared to individuals without implants, both modular THA and non-modular THA showed elevated titanium ion levels. Absolute titanium ion levels, however, were comparatively low for both implants. The data suggest that the present modular stem system does not result in elevated systemic titanium ion levels in the medium term when compared to non-modular stems. Further longitudinal studies are needed to evaluate the use of systemic titanium ion levels as an objective diagnostic tool to identify THA failure and to monitor patients following revision surgery.

Versatile application of short stem during total hip arthroplasty

Total hip arthroplasty (THA) is one of the most commonly performed orthopedic surgery worldwide. Current research and development had improved the designs of modern total hip prosthesis. Although long femoral stems are widely used, short stems are thought to preserve more native host bone and optimize proximal load transfer utilized with the advent of less invasive surgery. Modular short femoral stems in THA may have versatile applicability by virtue of their unique geometry, mechanism of fixation, and modularity. In this report, we present two unique case scenarios where the use of short stems has given successful results.

Comparison of mesenchymal stem cell proliferation and differentiation between biomimetic and electrochemical coatings on different topographic surfaces

The hypothesis for this study was that there is no difference in mesenchymal stem cells (MSCs) proliferation and osteogenic differentiation between calcium-phosphate (CaP) coatings with different crystal size deposited on different topographic surfaces of metal discs. Polished (P) and sand-blasted (SB) tantalum and TiAl6V4 discs were CaP coated by three methods-biomimetic (BioM), electrochemical at 20 mA/cm(2) and at 6.5 mA/cm(2)-and cultured with MSCs. At days 4, 7 and 14, cell proliferation-alamarBlue(®) activity and DNA quantification-and differentiation down the osteogenic lineage-ALP activity normalised per amount of DNA and SEM (morphology)-were analysed. Results showed that MSCs proliferated more when cultured on the nano-sized BioM coatings compared to uncoated and electrochemically coated discs. MSCs also proliferated more on P surfaces than on SB and or electrochemical coatings. All the coatings induced osteogenic differentiation, which was greater on electrochemical coatings and SB discs.

Cementless metaphyseal fitting anatomic total hip arthroplasty with a ceramic-on-ceramic bearing in patients thirty years of age or younger

BACKGROUND

The number of midterm or long-term studies on the current generation of cementless total hip replacements with alumina-on-alumina ceramic bearings in patients younger than thirty years of age is limited. The purpose of this study was to evaluate the midterm results of the cementless metaphyseal fitting anatomic total hip prosthesis in patients younger than thirty years of age, with a particular emphasis on the prevalence of thigh pain, resorption of bone due to stress-shielding of the proximal part of the femur, aseptic loosening, and osteolysis.

METHODS

We reviewed the cases of ninety-six patients (127 hips) who had a cementless total hip arthroplasty when they were thirty years or younger at the time of surgery. All surgical procedures were performed by a single surgeon. The most common diagnoses were osteonecrosis (54.3%) and developmental dysplasia of the hip (20.5%). Demographic data, the Harris hip score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and University of California, Los Angeles (UCLA) activity scores were recorded. Radiographic evaluation was used to evaluate implant fixation and osteolysis. The minimum follow-up interval was ten years (mean, 14.6 years; range, ten to sixteen years).

RESULTS

The mean preoperative Harris hip score, WOMAC score, and UCLA activity score were 41 points, 66 points, and 3 points, respectively. At the time of final follow-up, the mean Harris hip score, WOMAC score, and UCLA activity score were 95 points, 16 points, and 8 points, respectively. No patient had thigh pain after one year postoperatively. All of the femoral stems and all but one of the acetabular components were well-fixed at the time of final follow-up. No hip exhibited squeaking, ceramic fracture, loosening, or osteolysis at the time of the final follow-up.

CONCLUSIONS

These results in patients thirty years of age or younger suggest that the cementless metaphyseal fitting anatomic total hip prosthesis provides outstanding midterm fixation and substantial pain relief well into the second decade postoperatively. Moreover, the alumina-on-alumina ceramic bearing provides a high rate of survivorship without osteolysis.

Modern proximally tapered uncemented stems can be safely used in Dorr type C femoral bone

Cementless femoral fixation has become widely accepted in modern total hip arthroplasty. Treating patients who have a stovepipe-shaped femur (Dorr type C) with cementless implants has traditionally been challenging. We treated 53 consecutive patients (60 hips) who had type C bone with identical tapered, proximally coated implants and postoperative weight bearing as tolerated. At 6 weeks, all 60 hips had radiographically documented bony integration, and at 1 year, there was no evidence of fracture, subsidence, thigh pain, stress shielding, loose stems, or risk of failure. Of those patients, 40 (43 hips) had midterm follow-up (average, 6 years; range, 4-9 years); the findings were the same. We conclude that modern proximally tapered stems can be used with early weight bearing in patients with type C bone.

Total hip arthroplasty: to cement or not to cement the acetabular socket? A critical review of the literature

The optimal method for acetabular socket fixation remains controversial. We present a critical analysis of the current evidence from a systemic literature review of comparative studies, long-term case series, prior literature reviews, meta-analysis, and national arthroplasty registry data for cemented and uncemented acetabular components to determine the respective survivorship rates, overall risk of re-operation, dislocation rates, and wear-related complications. Using contemporary techniques, both cemented and uncemented sockets can yield good long-term results, but our evaluation suggests that the overall/all cause re-operation risk is lower for cemented fixation. Until and unless crosslinked polyethylene (PE) liners or alternative bearings can prove to yield superior outcome in the future, the cemented PE cup remains the gold standard, in all age groups, by which every acetabular component should be compared.

Straight tapered titanium stem with alumina bearing in cementless primary total hip arthroplasty: a minimum 5-year follow-up

The aim of this study was to assess the midterm results of primary cementless total hip arthroplasty using a tapered stem and alumina bearing couple in active patients. After a minimum of 5 years of follow-up, 78 arthroplasties in 72 patients were reviewed retrospectively. The mean Harris hip score was 94 points, and 2 hips had thigh pain. All components radiographically demonstrated stable fixation by bone ingrowth and mild stress shielding of the proximal femur were noted in 14% of hips. There was no significant osteolysis or aseptic loosening. There was a ceramic head fracture in 1 hip and audible sounds in 2 hips. The results of total hip arthroplasty with a straight, tapered, proximally porous-coated stem and alumina-on-alumina bearing were encouraging for active patients.

[Joint endoprosthesis pathology. Histopathological diagnostics and classification]

Prosthesis durability has steadily increased with high 10-year rates of 88-95%. However, four pathogenetic groups of diseases can decrease prosthesis durability: (1) periprosthetic wear particle disease (aseptic loosening) (2) bacterial infection (septic loosening) (3) periprosthetic ossification, and (4) arthrofibrosis. The histopathological "extended consensus classification of periprosthetic membranes" includes four types of membranes, arthrofibrosis, and osseous diseases of endoprosthetics: The four types of neosynovia are: wear particle-induced type (type I), mean prosthesis durability (MPD) in years 12.0; infectious type (type II), MPD 2.5; combined type (type III) MPD 4.2; and indeterminate type (type IV), MPD 5.5. Arthrofibrosis can be determined in three grades: grade 1 needs clinical information to be differentiated from a type IV membrane, and grades 2 & 3 can be diagnosed histopathologically. Periprosthetic ossification, osteopenia-induced fractures, and aseptic osteonecrosis can be histopathologically diagnosed safely with clinical information. The extended consensus classification of periprosthetic membranes may be a diagnostic groundwork for a future national endoprosthesis register.

Comparison of bone mineral density changes around short, metaphyseal-fitting, and conventional cementless anatomical femoral components

We investigated the incidence and degree of stress shielding and clinical and radiographic results in 2 groups of patients. Fifty patients (60 hips) in each group were enrolled for a randomized study. One group received a short, metaphyseal-fitting femoral component and another group received a conventional metaphyseal- and diaphyseal-filling femoral component. The mean follow-up was 3.35 years in both groups. Bone mineral density was significantly increased in femoral zone 1 but slightly decreased in zone 7 in the short, metaphyseal-fitting stem group. In the conventional metaphyseal- and diaphyseal-fitting stem group, bone mineral density was markedly decreased in both zones 1 and 7. Clinical and radiographic results were similar between the 2 groups. No hip in either group required revision of the component.

Clinical outcome of Zweymüller total hip arthroplasty for patients with high congenital hip dislocation

Treatment of high congenital dislocation of the hip (CDH) remains controversial. We report the outcome of hip arthroplasty using a cementless threaded cup and a cementless straight stem in patients with high congenital hip dislocation. Between January 2001 and August 2004, 17 patients with high congenital hip dislocation were treated. During surgery, at least 25% of the cup was anchored in bone. By monitoring somatosensory-evoked potentials (SEPs) of the common peroneal nerve we were able to reduce the femoral head into position in the true acetabulum by releasing soft tissues. A bulk autogenous femoral head bone graft was implanted in 5 patients to achieve at least 75% bony coverage of the acertabular component. Follow-up ranged from 48 months to 91 months with an average of 69.7 months. The mean Harris hip score increased from 43 points preoperatively to 89 points at the time of final follow-up (P<0.001). Radiographic analysis showed bony union of the bone graft in all cases.

Cementless total hip arthroplasty using the Spongiosa-I fully coated cancellous metal surface: a minimum twenty-year follow-up

BACKGROUND

We present the results of cementless total hip arthroplasty performed with use of an anatomically adapted femoral stem and hemispherical cup with a fully coated Spongiosa-I metal surface, which was designed to achieve a surface similar to human cancellous bone. The purpose of the present retrospective case series was to determine the long-term outcomes of this hip arthroplasty system after a minimum of twenty years of follow-up.

METHODS

Between 1983 and 1985, 209 consecutive total hip arthroplasty procedures (199 patients) were performed with use of the first-generation Spongiosa metal-surface chromium-cobalt total hip implant with an articulating surface consisting of a ceramic head and an ultra-high-molecular-weight polyethylene liner. We report the clinical and radiographic outcomes, the rates of and reasons for revision, and the influence of sex and age on outcome and complications.

RESULTS

At the time of the latest follow-up, twenty-seven patients had died and thirteen patients had been lost to follow-up; none of these forty patients had had revision surgery. The outcomes for 159 patients (169 prostheses) were reviewed. The mean duration of follow-up was 262 months (range, 242 to 275 months). There were nineteen revisions, including fourteen revisions of the femoral stem, two revisions of the acetabular cup, and three revisions of both components. The mean Harris hip score for patients who did not undergo revision surgery was 82 points. The probability of survival of both components at twenty years, with revision for any reason as the end point, was 97%. The probability of survival of the acetabular component was 98%, and the probability of survival of the femoral component only was 86%. The probability of component survival was significantly increased among older patients.

CONCLUSIONS

The results of cementless hip arthroplasty with use of the first-generation Spongiosa implant were excellent at a minimum of twenty years of follow-up. The probability of survival of the acetabular component exceeded that of the femoral stem.

High medium-term survivorship and durability of Zweymüller-Plus total hip arthroplasty

BACKGROUND AND PURPOSE

The Zweymüller-Plus system (SL-Plus stem, Bicon-Plus threaded cup) for primary total hip arthroplasty (THA) was introduced in 1993, as a successor of the Alloclassic THA with a few modifications in the conical stem shape and a new biconical threaded cup with a spherical shape. The medium-term performance of this system is not well established. To better understand the potential impact these design changes have had on (1) survivorship, (2) implant stability and (3) periprosthetic osteolysis, we studied patients who underwent THA using the SL-Plus stem and Bicon-Plus.

METHODS

We retrospectively reviewed the cases of 148 patients (153 hips) who underwent Zweymüller-Plus primary THA after an average of 11 years.

RESULTS

With revision for aseptic failure of biological fixation as the endpoint, survivorship was 98% for the stem and 100% for the cup. Focal osteolysis was observed in 6.6% of cups and 29% of stems. Four hips (2.6%) were revised because of aseptic failure of the biologic fixation and three hips (1.95%) for deep infection. As much as 146 stems and 149 cups were evaluated to be stable.

CONCLUSION

Zweymüller-Plus THA resulted in high survivorship and durability at 11 years, although the rate of osteolysis around the stem indicated polyethylene wear.

Prospective study of a cementless total hip arthroplasty with a collum femoris preserving stem and a trabeculae oriented pressfit cup: minimun 6-year follow-up

AIM

Tissue sparing hip prostheses are becoming more and more popular especially for the treatment of younger patients. The objective of this study was to evaluate the clinical and radiological results after insertion of a tissue sparing hip prosthesis.

METHOD

In 47 consecutive non-selected patients (50 hips), the clinical and radiographic results of cementless total hip arthroplasty using a collum femoris preserving stem, a pressfit cup and an alumina-polyethylene pairing were prospectively evaluated. The mean age at index-surgery was 58 (36-82) years, there were 38 women and 9 men. After a mean follow-up of 6.8 years (minimum 6.1 years), two patients had died and one patient underwent revision surgery due to aseptic loosening of the stem.

RESULTS

The overall survival rate of the acetabular component was 100% and of the femoral component 98%. The mean Harris hip score at follow-up was 94 points.

CONCLUSION

The mid-term survival with this type of total hip arthroplasty is excellent and compares equal with uncemented straight stems in this age group.

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.

Comparison of fully porous-coated and hybrid hip resurfacing: a minimum 2-year follow-up study

The purpose of this study was to compare clinical and radiological outcomes of the first 191 fully porous-coated hip resurfacing arthroplasties with 96 hybrid hip resurfacing arthroplasties performed during the same period at a minimum 2-year follow-up to evaluate the initial fixation of uncemented femoral resurfacing components. The results of this study indicate that fully porous-coated femoral resurfacing components can routinely achieve reliable fixation and provide similar initial results as have been achieved with cemented fixation. Long-term results are needed to determine which type of fixation is superior for the femoral hip resurfacing component.

What works best, a cemented or cementless primary total hip arthroplasty?: minimum 17-year followup of a randomized controlled trial

BACKGROUND

Total hip arthroplasty (THA) has been associated with high survival rates, but debate remains concerning the best fixation mode of THA.

QUESTIONS/PURPOSES

We conducted a randomized controlled trial (RCT) with 250 patients with a mean age of 64 years between October 1987 and January 1992 to compare the results of cementless and cemented fixation.

PATIENTS AND METHODS

Patients were evaluated for revision of either of the components. One hundred twenty-seven patients had died (51%) and 12 (4.8%) were lost to followup. The minimum 17-year followup data (mean, 20 years; range, 17-21 years) for 52 patients of the cementless group and 41 patients of the cemented group were available for evaluation.

RESULTS

Kaplan-Meier survivorship analysis at 20 years revealed lower survival rates of cemented compared with cementless THA. The cementless tapered stem was associated with a survivorship of 99%. Age younger than 65 years and male gender were predictors of revision surgery.

CONCLUSIONS

The efficacy of future RCTs can be enhanced by randomizing patients in specific patient cohorts stratified to age and gender in multicenter RCTs. Including only younger patients might improve the efficacy of a future RCT with smaller sample sizes being required. A minimum 10-year followup should be anticipated, but this can be expected to be longer if the difference in level of quality between the compared implants is smaller.

LEVEL OF EVIDENCE

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

The basic science of peri-implant bone healing

Given the popularity of cementless orthopedic implants, it is imperative for orthopedic surgeons to have a basic understanding of the process of peri-implant bone healing. Contact and distance osteogenesis have been used to explain peri-implant bone healing. In contact osteogenesis, de novo bone forms on the implant surface, while in distance osteogenesis, the bone grows from the old bone surface toward the implant surface in an appositional manner. Contact osteogenesis may lead to bone bonding if the surface of the implant displays the appropriate surface topography. The early stage of peri-implant bone healing is very important and involves the body's initial response to a foreign material: protein adsorption, platelet activation, coagulation, and inflammation. This results in the formation of a stable fibrin clot that is a depot for growth factors and allows for osteoconduction. Osteoconduction is the migration and differentiation of osteogenic cells, such as pericytes, into osteoblasts. Osteoconduction allows for contact osteogenesis to occur at the implant surface. The late stage of healing involves the remodeling of this woven bone. In many respects, this process is similar to the bone healing occurring at a fracture site.

Bone remodeling in proximal HA-coated versus uncoated cementless SL-Plus((R)) femoral components: a 5-year follow-up study

BACKGROUND AND PURPOSE

Bone resorption at the femoral stem due to stress shielding has been particularly observed secondary to cementless hip replacement. This prospective study of 126 total-hip replacements was performed to examine clinical outcomes and changes in peri-prosthetic bone density after implantation of a double-tapered cementless femoral component manufactured with versus without hydroxyapatite (HA) coating.

METHODS

Sixty-seven femoral components with and 59 femoral components without proximal HA coating were implanted and examined after a mean follow-up of 5.8 (SD 1.1, 2.8-7.8) years. The Harris hip score (HHS) and plain radiographs were used for clinical and radiological follow-up evaluations. Possible changes in peri-prosthetic bone mineral density (BMD) were measured by dual-energy X-ray absorptiometry (DEXA).

RESULTS

Clinical outcome, measured by HHS, was similar in both groups. On plain radiographs, significantly less radiolucent lines were observed for the coated implants. DEXA revealed a significant increase in BMD at the proximal zones, along the medial side, and at the stem tips in the coated compared with the non-coated implants.

INTERPRETATION

Hydroxyapatite-coated implants yield favorable radiographic characteristics, but no greater clinical benefit after 5 years' implantation.