Triple taper stem design shows promising fixation and bone remodelling characteristics: radiostereometric analysis in a randomised controlled trial

Early migration of a medially stabilized total knee arthroplasty : a radiostereometric analysis study up to two years

Aims

Medial pivot (MP) total knee arthroplasties (TKAs) were designed to mimic native knee kinematics with their deep medial congruent fitting of the tibia to the femur almost like a ball-on-socket, and a flat lateral part. GMK Sphere is a novel MP implant. Our primary aim was to study the migration pattern of the tibial tray of this TKA.

Methods

A total of 31 patients were recruited to this single-group radiostereometric analysis (RSA) study and received a medial pivot GMK Sphere TKA. The distributions of male patients versus female patients and right versus left knees were 21:10 and 17:14, respectively. Mean BMI was 29 kg/m² (95% confidence interval (CI) 27 to 30) and mean age at surgery was 63 years (95% CI 61 to 66). Maximum total point motions (MTPMs), medial, proximal, and anterior translations and transversal, internal, and varus rotations were calculated at three, 12, and 24 months. Patient-reported outcome measure data were also retrieved.

Results

MTPMs at three, 12, and 24 months were 1.0 mm (95% CI 0.8 to 1.2), 1.3 mm (95% CI 0.9 to 1.7), and 1.4 mm (0.8 to 2.0), respectively. The Forgotten Joint Score was 79 (95% CI 39 to 95) and Knee Injury and Osteoarthritis Outcome Score obtained at two years was 94 (95% CI 81 to 100), 86 (95% CI 75 to 93), 94 (95% CI 88 to 100), 69 (95% CI 48 to 88), and 81 (95% CI59 to 100) for Pain, Symptoms, Activities of Daily Living, Sport & Recreation, and Quality of Life, respectively.

Conclusion

In conclusion, we found that the mean increase in MTPM was lower than 0.2 mm between 12 and 24 months and thus apparently stable. Yet the GMK Sphere had higher migration at one and two years than anticipated. Based on current RSA data, we therefore cannot conclude on the long-term performance of the implant, pending further assessment.

Cite this article: Bone Jt Open 2021;2(9):737–744.

Cement-in-cement femoral component revision : a comparison of two different taper-slip designs with medium-term follow up

AIMS

Cement-in-cement revision of the femoral component represents a widely practised technique for a variety of indications in revision total hip arthroplasty. In this study, we compare the clinical and radiological outcomes of two polished tapered femoral components.

METHODS

From our prospectively collated database, we identified all patients undergoing cement-in-cement revision from January 2005 to January 2013 who had a minimum of two years' follow-up. All cases were performed by the senior author using either an Exeter short revision stem or the C-Stem AMT high offset No. 1 prosthesis. Patients were followed-up annually with clinical and radiological assessment.

RESULTS

A total of 97 patients matched the inclusion criteria (50 Exeter and 47 C-Stem AMT components). There were no significant differences between the patient demographic data in either group. Mean follow-up was 9.7 years. A significant improvement in Oxford Hip Score (OHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 12-item Short-Form Survey (SF-12) scores was observed in both cohorts. Leg lengths were significantly shorter in the Exeter group, with a mean of -4 mm in this cohort compared with 0 mm in the C-Stem AMT group. One patient in the Exeter group had early evidence of radiological loosening. In total, 16 patients (15%) underwent further revision of the femoral component (seven in the C-Stem AMT group and nine in the Exeter group). No femoral components were revised for aseptic loosening. There were two cases of femoral component fracture in the Exeter group.

CONCLUSION

Our series shows promising mid-term outcomes for the cement-in-cement revision technique using either the Exeter or C-Stem AMT components. These results demonstrate that cement-in-cement revision using a double or triple taper-slip design is a safe and reliable technique when used for the correct indications. Cite this article: Bone Joint J 2021;103-B(7):1215-1221.

Minimum ten-year outcome of a triple-tapered femoral stem implanted with line-to-line cementing technique

Background

A triple-tapered polished femoral stem was implanted with line-to-line cementing technique. The purpose of this study was to determine the survivorship, loosening rate, stem subsidence, radiologic changes and clinical outcomes in the minimum 10-year follow-up.

Methods

This was a retrospective study done in three institutes. Finally, 118 hips in 97 patients could be followed-up at the mean follow-up period of 126.3 months. The survivorship, radiological and clinical outcomes were investigated.

Results

Radiologically, 107 hips (90.7%) were categorized to Barrack cementing grade A, and 108 stems (91.5%) were inserted in neutral position. All hips were not loose and were not revised due to any reason. Survival with revision for any reason as the endpoint was 100% after 10 years. At the last follow-up, the mean subsidence was 0.43 mm, and the subsidence was less than 1 mm in 110 hips (93.2%).

JOA hip score improved from 42.7 ± 8.9 points preoperatively to 92.8 ± 6.8 points at the last follow-up. No patient complained thigh pain.

Conclusions

Line-to-line cementing technique with use of a triple-tapered polished stem was effective to achieve good cementation quality and centralization of the stem. The subsidence was small, and the minimum 10-year results were excellent without any failures related to the stem.

Trial registration

Retrospectively registered.

Temporal subsidence patterns of cemented polished taper-slip stems: a systematic review

The literature was reviewed to establish the levels of stem subsidence for both double and triple-tapered implants in order to determine whether there were any differences in subsidence levels with regard to the methods of measurement, the magnitude and rate of subsidence and clinical outcomes.

All studies reporting subsidence of polished taper-slip stems were identified. Patient demographics, implant design, radiological findings, details of surgical technique, methods of measurement and levels of subsidence were collected to investigate which factors were related to increased subsidence.

Following application of inclusion and exclusion criteria, 28 papers of relevance were identified. The studies initially recruited 3090 hips with 2099 being available for radiological analysis at final follow-up. Patient age averaged 68 years (42–70), 60.4% were female and the average body mass index (BMI) was 27.4 kg/m² (24.1–29.2).

Mean subsidence at one, two, five and 10 years was 0.97 mm, 1.07 mm, 1.47 mm and 1.61 mm respectively. Although double-tapered stems subsided more than triple-tapered stems at all time points this was not statistically significant (p > 0.05), nor was the method of measurement used (p > 0.05).

We report the levels of subsidence at which clinical outcomes and survivorship remain excellent, but based on the literature it was not possible to determine a threshold of subsidence beyond which failure was more likely.

There were relatively few studies of triple-tapered stems, but given that there were no statistically significant differences, the levels presented in this review can be applied to both double and triple-tapered designs.

Cite this article: EFORT Open Rev 2021;6:331-342. DOI: 10.1302/2058-5241.6.200086

Two-year migration characteristics of a novel cementless femoral stem: a radiostereometric analysis and clinical outcomes study

BACKGROUND

Radiostereometric analysis (RSA) is an established high precision tool enabling us to detect early implant migration in total hip arthroplasty. The aim of this study is to present the RSA and clinical results of a new cementless hip stem and to compare those with established benchmarks.

METHODS

A total of 45 patients (46 hips) undergoing total hip arthroplasty were available for full radiographic and clinical assessment at 2 years post-operatively. Mean patient age was 69 (range 43-85) years and mean body mass index was 29 (range 21-38) kg/m² . RSA was undertaken at day 1, 6 weeks, 6 months and 1 and 2 years post-operatively. Oxford hip score and EQ-5D-5L scores were recorded preoperatively and at the same other time points. Results were compared to published data of established implants.

RESULTS

At 2 years, mean subsidence and retroversion were 0.61 mm (standard deviation 0.7 mm, range -0.19 to 3.06 mm) and 0.44° (standard deviation 0.81°, range 0.98 to 3.29°), respectively. Stem migration occurred primarily in the first 6 weeks with no detectable subsidence or rotation at 6 months or 2 years. Mean Oxford hip score and EQ-5D-5L improved from 18.6 to 44.7, and 69 to 86, respectively. There was one cup-only revision and no revisions for stem loosening.

CONCLUSION

RSA serves as an accurate measure of femoral stem stability early in the post-operative period. Our data confirm that stability occurs as early as 6 weeks and is sustained at 2 years. The Paragon stem demonstrates stability parameters at 2 years that exceed other established benchmark implants.

The Long-Term Results of Total Hip Arthroplasty With a Cemented β-Titanium Stem

BACKGROUND

We report on the outcomes of a double-tapered cemented stem made of β-titanium alloys (Ti-15Mo-5Zr-3Al) at least 10 years after total hip arthroplasty.

METHODS

We retrospectively analyzed 148 consecutive, primary total hip arthroplasties using this stem performed in 130 patients between January 2004 and August 2008. The patients' mean age was 59.6 years (range, 24-79). Implant survival was evaluated using Kaplan-Meier curves with the primary end point being stem revision for any reason and the secondary end point being stem revision for aseptic stem loosening. We also clinically and radiologically followed 140 hips (in 123 patients) for an average of 12.2 years (range, 10-15).

RESULTS

The only revisions were for 2 stems with deep infection. Ten-year survival was 99.3% (95% confidence interval, 95.4%-99.9%) and 100% for the primary and secondary end point, respectively. The mean Japanese Orthopaedic Association hip score improved from 51.4 preoperatively to 88.7 at the last follow-up. Radiolucent lines at the stem-cement interface were seen in 14 hips (10.0%). None of the hips met the criteria of radiological stem loosening. Nineteen stems (13.6%) subsided by around 1 mm between 2 and 8 years after surgery. Distal femoral cortical hypertrophy occurred in 24 hips (17.0%), mostly with valgus alignment.

CONCLUSION

The clinical outcomes of the femoral stems were excellent with survival at 10 years. Stem subsidence and distal femoral cortical hypertrophy did not affect the results. Long-term use of β-titanium alloy stems is safe and effective.

Current concepts and outcomes in cemented femoral stem design and cementation techniques: the argument for a new classification system

Cemented implant fixation design principles have evolved since the 1950s, and various femoral stem designs are currently in use to provide a stable construct between the implant-cement and cement-bone interfaces.Cemented stems have classically been classified into two broad categories: taper slip or force closed, and composite beams or shaped closed designs. While these simplifications are acceptable general categories, there are other important surgical details that need to be taken into consideration such as different broaching techniques, cementing techniques and mantle thickness.With the evolution of cemented implants, the introduction of newer implants which have hybrid properties, and the use of different broaching techniques, the classification of a very heterogenous group of implants into simple binary categories becomes increasingly difficult. A more comprehensive classification system would aid in comparison of results and better understanding of the implants' biomechanics.We review these differing stem designs, their respective cementing techniques and geometries. We then propose a simple four-part classification system and summarize the long-term outcomes and international registry data for each respective type of cemented prosthesis. Cite this article: EFORT Open Rev 2020;5:241-252. DOI: 10.1302/2058-5241.5.190034.

Cemented Exeter total hip arthroplasty with a 32 mm head on highly crosslinked polyethylene: Does age influence functional outcome, satisfaction, activity, stem migration, and periprosthetic bone mineral density?

Objectives

Our primary aim was to describe migration of the Exeter stem with a 32 mm head on highly crosslinked polyethylene and whether this is influenced by age. Our secondary aims were to assess functional outcome, satisfaction, activity, and bone mineral density (BMD) according to age.

Patients and Methods

A prospective cohort study was conducted. Patients were recruited into three age groups: less than 65 years (n = 65), 65 to 74 years (n = 68), and 75 years and older (n = 67). There were 200 patients enrolled in the study, of whom 115 were female and 85 were male, with a mean age of 69.9 years (sd 9.5, 42 to 92). They were assessed preoperatively, and at three, 12 and, 24 months postoperatively. Stem migration was assessed using Einzel-Bild-Röntgen-Analyse (EBRA). Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS), Hip Disability and Osteoarthritis Outcome Score (HOOS), EuroQol-5 domains questionnaire (EQ-5D), short form-36 questionnaire (SF-36,) and patient satisfaction were used to assess outcome. The Lower Extremity Activity Scale (LEAS), Timed Up and Go (TUG) test, and activPAL monitor (energy expelled, time lying/standing/walking and step count) were used to assess activity. The BMD was assessed in Gruen and Charnley zones.

Results

Mean varus/valgus tilt was -0.77⁰ and axial subsidence was -1.20 mm. No significant difference was observed between age groups (p ⩾ 0.07). There was no difference according to age group for postoperative WOMAC (p ⩾ 0.11), HHS (p ⩾ 0.06), HOOS (p ⩾ 0.46), EQ-5D (p ⩾ 0.38), patient satisfaction (p ⩾ 0.05), or activPAL (p ⩾ 0.06). Patients 75 years and older had a worse SF-36 physical function (p = 0.01) and physical role (p = 0.03), LEAS score (p < 0.001), a shorter TUG (p = 0.01), and a lower BMD in Charnley zone 1 (p = 0.02).

Conclusion

Exeter stem migration is within normal limits and is not influenced by age group. Functional outcome, patient satisfaction, activity level, and periprosthetic BMD are similar across all age groups.

Cite this article: N. D. Clement, M. Bardgett, K. Merrie, S. Furtado, R. Bowman, D. J. Langton, D. J. Deehan, J. Holland. Cemented Exeter total hip arthroplasty with a 32 mm head on highly crosslinked polyethylene: Does age influence functional outcome, satisfaction, activity, stem migration, and periprosthetic bone mineral density? Bone Joint Res 2019;8:275–287. DOI: 10.1302/2046-3758.86.BJR-2018-0300.R1.

Equivalent hip stem fixation by Hi-Fatigue G and Palacos R + G bone cement: a randomized radiostereometric controlled trial of 52 patients with 2 years' follow-up

Background and purpose - Long-term fixation of cemented femoral stems relies on several factors including cement adhesion and fatigue. Hi-Fatigue is a newer third-generation bone cement with low-viscosity properties at room temperature, good mechanical strength, and stable bone-cement interface in a laboratory testing environment. Palacos bone cement has excellent 10-year survival and is considered gold standard. We compared stem subsidence after fixation with Hi-Fatigue and Palacos bone cements using radiostereometry. Patients and methods - In a patient-blinded randomized controlled trial, 52 patients (30 women) at mean age 76 years (71-87) with osteoarthrosis and no osteoporosis received Hi-Fatigue G or Palacos R + G cement fixation of collarless, polished, double-tapered stems (CPT). Tantalum beads were inserted in the periprosthetic bone. Supine stereoradiographs were obtained postoperatively, 3 months, 6 months, 1 year, and 2 years after surgery. Oxford Hip Score (OHS) and VAS pain were recorded preoperatively and 1 and 2 years after surgery. Cement working times and properties were registered. Results - At 2 years, mean stem subsidence of 1.12 mm (95% CI 0.96-1.29) for Hi-Fatigue and 1.19 mm (CI 1.03-1.34) for Palacos was similar. Likewise, stem version was comparable between cement groups. Mean OHS and VAS pain were similar between cement groups. Cement working times were similar between cement groups, but the mean curing time was longer for Hi-Fatigue (13.7 min) than for Palacos (11.6 min). Interpretation - We found similar and generally low migration of CPT femoral stems inserted with Hi-Fatigue and Palacos bone cement until 2 years' follow-up, which indicates a good long-term survival of polished taper femoral stems inserted with both cement types.