Introduction

Beneath infection, instability and malalignment, aseptic tibial component loosening remains a major cause of failure in total knee arthroplasty (TKA) [1]. This emphasizes the need for stable primary and long-term secondary fixation of tibial baseplates. To evaluate the primary stability of cemented tibial baseplates, different pre-clinical test methods have been undergone: finite element analysis [2], static push-out [3,4] or dynamic compression-shear loading [5] until interface failure. However, these test conditions do not reflect the long-term endurance under in vivo loading modes, where the tibial baseplate is predominantly subjected to compression and shear forces in a cyclic profile [5,6].

To distinguish between design parameters the aim of our study was to develop suitable pre-clinical test methods to evaluate the endurance of the implant-cement-bone interface fixation for tibial baseplates under severe anterior (method I) and internal-external torsional (method II) shear test conditions.

Introduction

The THR is the second most successful and cost-effective surgical procedure of all time. Data shows that hip cup failure is a significant problem. The aim of this study is to improve methods of cemented cup fixation through validation experiments and FEA.

Modular hip prostheses were introduced to optimize the intra-surgical adaptation of the implant design to the native anatomy und biomechanics of the hip. The downside of a modular implant design with an additional modular interface is the potential susceptibility to fretting, crevice corrosion and wear. For testing hip implants with proximal femoral modularity according to ISO & ASTM, sodium chloride solutions are frequently used to determine the fatigue strength and durability of the stem-neck connection. The present study illustrate that the expansion of standard requirements of biomechanical testing is necessary to simulate metal ion release as well as fretting and crevice corrosion by using alternative test fluids. To assess the primary stability of tibial plateaus in vitro, different approaches had been undergone: cement penetration depth analysis, static tension or compression loading until interface failure. However, these test conditions do not reflect the in vivo physiologic loading modes, where the tibial plateau is predominantly subjected to combined compression and shear forces. The objectives were to evaluate the impact of the tibial keel & stem length on the primary stability of a posterior-stabilised tibial plateau under dynamic compression-shear loading conditions in human tibiae.

We performed a systematic review to compare outcomes of cemented versus uncemented trapezio-metacarpal joint (TMCJ) replacement for treatment of base-of-thumb arthritis.

We assessed improvements in pain and function, range of movement (ROM), strength, complications and need for revision surgery. A thorough literature search was performed. A total of 481 studies were identified from the literature search (179 Medline, 253 Embase, 27 CINAHL, 22 Cochrane). Of 43 relevant titles 28 were selected for full-text review after assessment of the abstracts. Duplicate studies were removed. 18 studies met inclusion criteria on full-text review. All studies were of level IV evidence. There were no randomised controlled trials or meta-analyses. The studies were critically appraised using a validated scoring system.

Most studies reported good outcomes for pain and strength, and functional outcome was comparable for both groups. ROM was generally improved for both prosthetic types, however statistical calculation was lacking in many studies. Trapezial component loosening was the main problem for both cemented and uncemented prostheses, however radiological loosening did not necessarily correlate with implant failure.

This systematic review has found that both cemented and uncemented replacements generally give good outcomes for the treatment of TMCJ arthritis, however young, male, patients with manual occupations and with disease in the dominant hand and patients with poor trapezial bone stock appear to be at higher risk for implant failure due to cup loosening. We recommend the construction of a joint registry to record implantation and revision rates.

Although cemented fixation provides excellent results in primary total hip replacement (THR), particularly in patients older than 75 years, uncemented implants are most commonly used nowadays. We compare the rate of complications, clinical and radiological results of three different designs over 75-years-old patients.

433 hips implanted in patients over 75 years old were identified from our Local Joint Registry. Group A consisted of 139 tapered cemented hips, group B of 140 tapered grit-blasted uncemented hips and group C of 154 tapered porous-coated uncemented hips. A 28 mm femoral head size on polyethylene was used in all cases. The mean age was greater in group A and the physical activity level according to Devane was lower in this group (p<0.001 for both variables). Primary osteoarthritis was the most frequent diagnoses in all groups. The radiological acetabular shape was similar according to Dorr, however, an osteopenic-cylindrical femur was most frequently observed in group A (p<0.001). The pre- and post-operative clinical results were evaluated according to the Merle-D'Aubigne and Postel scale. Radiological cup position was assessed, including hip rotation centre distance according to Ranawat and cup anteversion according to Widmer. We also evaluated the lever arm and height of the greater trochanter distances and the stem position. Kaplan-Meier analysis was done for revision for any cause and loosening.

The hip rotation centre distance was greater and the height of the greater trochanter was lower in group B (p=0.003, p<0.001, respectively). The lever arm distance was lower in group C (p<0.001). A varus stem position was more frequently observed in group B (p<0.001). There were no intra- or post-operative fractures in group A, although there were five intra-operative fractures in the other groups plus two post-operative fractures in group B and four in group C. The rate of dislocation was similar among groups and was the most frequent cause for revision surgery (8 hips for the whole series). The mean post-operative clinical score improved in all groups. The overall survival rate for revision for any cause at 120 months was 88.4% (95% CI 78.8–98), being 97.8% (95% CI 95.2–100) for group A, 81.8% (95% CI 64.8–98.8) for group B and 95.3% (95% CI 91.1–99.6) for group C (log Rank: 0.416). Five hips were revised for loosening. The overall survival rate for loosening at 120 months was 91.9% (95% CI 81.7–100), being 99.2%(95% CI 97.6–100) for group A, 85.5 (95% CI 69.9 −100) for group B and 100% for group C (Log Rank 0.093).

Despite a more osteopenic bone in the cemented group, the rate of peri-prosthetic fractures was higher after uncemented THR in patients older than 75 years. Although the overall outcome is good with both types of fixation, the post-operative reconstruction of the hip, which might be more reliable after cemented fixation, may affect the rate of complications in this population.

Prosthesis migration and acetabular cup wear are useful short term measurement which may predict later implant outcome. However, the significance of the magnitude and pattern of the migration is very much dependent on the specific design studied. This study aimed to characterise patterns of migration by following four cemented femoral stem designs using Radiostereometry (RSA) within a prospective randomised longitudinal trial.

164 patients undergoing cemented femoral hip replacement for osteoarthritis were randomised to receive either an Exeter (Howmedica Stryker), Ultima Tapered Polished Stem (TPS) (Depuy), Ultima Straight Stem (USS) (Johnson and Johnson) or Elite Plus (Depuy) stem. Each subject received the OGEE PE cemented acetabular component (Depuy). RSA examinations were performed at 1 week and 6, 12, 18, 24 and 60 months post surgery. They were analysed using the UMRSA system (RSA Biomedical AB, Umea, Sweden), and our local geometric stem measurement software. 149 patients had RSA measurements available to 2 years, and 96 patients to 5 years. Differences were analysed using mixed linear modelling (SPSS).

Median linear proximal cup wear rate reduced to a minimum of 0.02-0.06mm/year in year two. Between 2 and 5 years the wear rate increased, being significantly higher for the Elite.

Cup migration was small but continuous. At 2 years it was median 0.3mm proximally, increasing to 0.5 mm at 5 years. Median rotations were less than 0.3 degrees.

Proximal migration was positive and increasing at all time points for all stems. For the tapered polished designs, while the overall magnitude was significantly higher, the rate of migration significantly decreased, whereas for the other stem designs it did not.

The TPS stem showed a tendency for posterior tilt which was significant compared to the other stems at 5 years.

All stems tended to retroversion, with the USS significantly less than the others and the Elite showing and relative increase at 5 years.

In summary migration patterns are characterised by the stem design, including where there were only small changes between designs. We are now testing measured migrations as predictors of outcome, and will continue to follow this group of patients to 10 years.

250 words max Long polished cemented femoral stems, such as the Exeter Hip Revision stem, are one option available to the revision hip arthroplasty surgeon. When proximal bone stock is compromised, distal fixation is often relied upon for stability of the femoral component. In such circumstances, torsional forces can result in debonding and loosening. This study compared the torsional behaviour of a cemented polished and featureless (plain) stem with cemented, polished stems featuring fins or flutes. Nine torsional tests were carried out on each of these three different stem designs. The finned stem construct was significantly stiffer than the fluted stem (mean 24.5 Nm/deg v 17.5 Nm/deg). The plain stem mean stiffness was less than the featured stems (13 Nm/deg), but wide variability lead to no statistically significant difference. The maximum torque of the finned (30.5 Nm) and fluted stems (29 Nm) was significantly higher than the plain stem (10.5 Nm); with no significance to the difference between the finned and fluted stems. Distal stem features may provide a more reliable and greater resistance to torque in polished, cemented revision hip stems. Finned stem features may also increase the stiffness of the construct. Consideration should thus be given to the incorporation of distal stem features in the design of revision hip stems.

Summary

Particulate wear debris with different chemical composition induced similar periprosthetic tissue reactions in patients with loosened uncemented and cemented titanium hip implants, which suggests that osteolysis can develop independent of particle composition.

Summary Statement

We analysed impaction bone grafting used together with cemented or uncemented fixation in acetabular revision surgery. The overall risk for re-revision did not differ between the cemented and uncemented group. However, aseptic loosening was more common in the cemented group.

Introduction

Total hip arthroplasties (THAs) in young patients are associated with high failure rates. We always use cemented total hip implants, however, in cases with acetabular bone stock loss we perform bone impaction grafting. Our purpose was to evaluate the outcome of 69 consecutive primary cemented total hips in patients younger than 30 years followed between 2 to 18 years.

Abstract. Objective. Up to 20% of patients can remain dissatisfied following TKR. A proportion of TKRs will need early revision with aseptic loosening the most common. The ATTUNE TKR was introduced in 2011 as successor to its predicate design The PFC Sigma (DePuy Synthes, Warsaw, In). However, following reports of early failures of the tibial component there have been ongoing concerns of increased loosening rates with the ATTUNE TKR. In 2017 a redesigned tibial baseplate (S+) was introduced, which included cement pockets and an increased surface roughness to improve cement bonding. Given the concerns of early tibial loosening with the ATTUNE knee system, this study aimed to compare revision rates and those specific to aseptic loosening of the ATTUNE implant in comparison to an established predicate as well as other implant designs used in a high-volume arthroplasty centre. Methods. The Attune TKR was introduced to our unit in December 2011. Prior to this we routinely used a predicate design with an excellent long-term track record (PFC Sigma) which remains in use. In addition, other designs were available and used as per surgeon preference. Using a prospectively maintained database, we identified 10,202 patients who underwent primary cemented TKR at our institution between 01/04/2003–31/03/2022 with a minimum of 1 year follow-up (Mean 8.4years, range 1–20years): 1) 2406 with ATTUNE TKR (of which 557 were S+) 2) 4652 with PFC TKR 3) 3154 with other cemented designs. All implants were cemented using high viscosity cement. The primary outcome measures were all-cause revision, revision for aseptic loosening, and revision for tibial loosening. Kaplan-Meier survival analysis and Cox regression models were used to compare the primary outcomes between groups. Matched cohorts were selected from the ATTUNE subsets (original and S+) and PFC groups using the nearest neighbor method for radiographic analysis. Radiographs were assessed to compare the presence of radiolucent lines in the Attune S+, standard Attune, and PFC implants. Results. At a mean of 8.4 years follow-up, 308 implants underwent revision equating to 3.58 revisions per 1000 implant-years. The lowest risk of revision was noted in the ATTUNE cohort with 2.98 per 1000-implant-years where the PFC and All Other Implant groups were 3.15 and 4.4 respectively. Aseptic loosing was the most common cause for revision across all cemented implants with 76% (65/88) of involving loosening of the tibia. Survival analysis comparing the ATTUNE cohort to the PFC and All Other Cemented Implant cohorts showed no significant differences for: all-cause revision, aseptic loosening, or tibial loosening (p=0.15,0.77,0.47). Radiolucent lines were detected in 4.6%, 5.8%, and 5.0% of the ATTUNE S+, standard ATTUNE, and PFC groups respectively. These differences were not significant. Conclusion. This study represents the largest non-registry review of the original and S+ ATTUNE TKR in comparison to its predicate design as well as other cemented implants. There appears to be no significant increased revision rate for all-cause revision or aseptic loosening. Radiographic analysis also showed no significant difference in peri-implant radiolucency. It appears that concerns of early loosening may be unfounded. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

Abstract. Objectives. Stem malalignment in total hip arthroplasty (THA) has been associated with poor long-term outcomes and increased complications (e.g. periprosthetic femoral fractures). Our understanding of the biomechanical impact of stem alignment in cemented and uncemented THA is still limited. This study aimed to investigate the effect of stem fixation method, stem positioning, and compromised bone stock in THA. Methods. Validated FE models of cemented (C-stem – stainless steel) and uncemented (Corail – titanium) THA were developed to match corresponding experimental model datasets; concordance correlation agreement of 0.78 & 0.88 for cemented & uncemented respectively. Comparison of the aforementioned stems was carried out reflecting decisions made in the current clinical practice. FE models of the implant positioned in varus, valgus, and neutral alignment were then developed and altered to represent five different bone defects according to the Paprosky classification (Type I – Type IIIb). Strain was measured on the femur at 0mm (B1), 40mm (B2), and 80mm (B3) from the lesser trochanter. Results. Cemented constructs had lower strain on the implant neck, and higher overall stiffness and strain on bone compared to uncemented THA. Strain on the bone increased further down the shaft of the femoral diaphysis, and with progressing bone defect severity in all stem alignment cases. Highest strain on the femur was found at B2 in all stem alignment and bone defect models. Varus alignment showed higher overall femoral strain in both fixation methods. Interestingly, in uncemented models, highest strain was shown on femoral bone proximally (B1-B2) in varus alignment, but distally (B3) in neutral alignment. Conclusion. Varus stem alignment showed overall higher strain on femur compared to neutral and valgus. This highlights the crucial role of stem alignment in long term outcomes of THA. Differences between the two stem types should be taken in consideration when interpreting results from this study

Displaced fractures of the neck of femur are routinely treated in the elderly by either cemented hemiarthoplasty, in the fit, or uncemented hemiarthroplasty, in the less fit. In Scotland the Scottish Intercollegiate Guidelines Network (SIGN) guidelines are followed to identify which patients should have a cemented prosthesis. This is based on cardiovascular status, and the age and fragility of the patient. An uncemented prosthesis should be a final operation. A peri-prosthetic fracture is considered a failure of treatment as the patient then has to undergo an operation with a far greater surgical insult. We looked at all neck of femur fractures over a period of Jan 2007 to June 2010. The number of the peri-prosthetic fractures for uncemented hip hemiarthroplasties was established, and a case note review was carried out. There was 1397 neck of femur fractures. 546 hemiarthroplasties were carried out, of which 183 were cemented, and 363 uncemented. 15 patients (4% of uncemented hemiarthoplasties) had peri-prosthetic fractures. There were no peri-prosthetic fractures in the cemented group, p = 0.004 using Fisher's exact test. The case notes of these patients were analysed. We found there was a common link of significant cardiovascular risk, lack of falls assessment (only 14% of the patients had a completed falls assessment and 21% sustained their fracture during an admission to hospital) and confusion (50% had a degree of dementia that caused significant confusion). Cemented implants should be considered in all patients, especially those who are cognitively impaired or have failed falls assessments; even if the cardiovascular risk is significant. This decision should be made in conjunction with a senior anaesthetist. This is being implemented in our unit and a prospective audit is being carried out over the same time period (July 2010 to Dec 2013) to assess the benefit

Displaced fractures of the neck of femur are routinely treated in the elderly by either cemented hemiarthoplasty, in the fit, or uncemented hemiarthroplasty, in the less fit. In Scotland the Scottish Intercollegiate Guidelines Network (SIGN) guidelines are followed to identify which patients should have a cemented prosthesis. This is based on cardiovascular status, and the age and fragility of the patient. An uncemeted prosthesis should be a final operation. A peri-prosthetic fracture is considered a failure of treatment as the patient then has to undergo an operation with a far greater surgical insult. We looked at all neck of femur fractures over a period of Jan 2007 to June 2010. The number of the peri-prosthetic fractures for uncemented hip hemiarthroplasties was established and a case note review carried out. There were 397 neck of femur fractures. 546 hemiarthroplasties were carried out, of which 183 were cemented, and 363 uncemented. 14 patients (4% of uncemented arthoplasties) had peri-prosthetic fractures. The case notes of these patients were analysed. There was a common link of significant cardiovascular risk, lack of falls assessment, and confusion. Cemented implants should be considered in those who have failed falls assessment, or are confused; even if the cardiovascular risk is significant. This decision should be made in conjunction with a senior anaethetist. This is being implemented in our unit and a prospective audit is being carried out over the same time period (July 2010 to Dec 2013) to assess the benefit

Over 70,000 hip fractures occur annually in the UK. Both SIGN (111) and NICE (124) give guidance on optimal management of these patients. Both suggest cemented hemiarthroplasty should be used in those without contra-indications, as cemented implants are associated with less thigh pain, subsidence and a better functional outcome. Cardiorespiratory compromise secondary to bone cement implantation syndrome (BCIS) is however a concern in those with pre-existing cardiorespiratory disease (NYHA grade 3–4, pulmonary hypertension) or pathological fracture [3]. The aim of our study was to audit the practice of a University of Glasgow hospital with regard to cemented hemiarthroplasty. We retrospectively reviewed data on all patients treated with hemiarthroplasty for hip fracture at the Southern General Hospital between 01/01/12-02/04/12. Patient demographics, pre-operative plan, procedure performed, ASA grade and pre-morbid mobility were recorded. Results. Twenty-three hemiarthroplasties were performed. The median age was 82 (70–101). No patient aged over 90 underwent cemented hemiarthroplasty. Cemented implants (JRI, Furlong) were used in 26% (n=6) while 74% (n=17) underwent uncemented (Stryker, Austin-Moore) hemiarthroplasty. ASA grade was recorded in eight (35%). There were four ASA-2 patients (mild systemic disease not limiting activity) of which 75% underwent uncemented hemiarthroplasty. Pre-morbid mobility was recorded in eight (35%). All three independently mobile patients underwent uncemented hemiarthroplasty. Six (26%) had a documented pre-operative plan with regards to cement use. This study highlights the disparity between current recommendations and our Centres’ practice. Most notable were: poor recording of pre-operative mobility, poor documentation of a pre-operative surgical plan, the low use of cemented fixation even in fit mobile patients and the lack of ASA grade recording (stratification of risk) by our anaesthetic colleagues. We suggest a documented pre-operative discussion between the surgeon and anaesthetist to establish BCIS risk and decide on use of cemented arthroplasty taking into account age and mobility

The price per total knee replacement (TKR) performed is fixed but the subsequent length of hospital stay (LOS) is variable. The current national average for LOS following TKR is six days. LOS is an important marker of resource consumption, has implications in patient satisfaction, and is used as a marker of hospital quality. The aim of this study was to describe the temporal change in demographics between 2004 and 2009, and to identify intra-operative factors and patient characteristics associated with a prolonged LOS that could be addressed to improve clinical practice. We performed a retrospective cohort review of 184 patients (2004 n=88, 2009 n=96) who underwent primary TKRs at Chorley District General Hospital. The median LOS in 2009 was eight days compared to ten days in 2004, an average of 3.5 days less (p < 0.001). Patients were significantly younger (p < 0.001) in 2009 (median 66 years) compared to 2004 (median 74 years), with both years having a similar female predominance. There was no significant change in the BMI or American Society of Anesthesiologists score between 2004 and 2009. This data suggests that block contracts with the private sector has not influenced the demographics of patients being treated in the NHS. Intra-operative factors including the use of a peripheral nerve block, the surgeon grade, the day of the week the operation was performed, the operation length, and the change in pre- to post-operative haemoglobin were not found to significantly increase the LOS (p = 0.058, p = 0.40, p = 0.092, p = 0.50, p = 0.43 respectively). Cemented TKRs had a median LOS of nine days compared to eight for uncemented implants (p = 0.015). However, patients with a cemented implant were on average 6.2 years older than patients with an uncemented implant (p < 0.001). Using Cox proportional hazard regression modelling, the occurrence of a post-operative complication (p < 0.001), female sex (p = 0.024), advancing age (p = 0.036), and the need for a blood transfusion (p = 0.0056) were the most significant factors for prolonging the LOS. Patients who were given a transfusion stayed a median of 13 days compared to nine for those who did not (p < 0.001). The median pre-operative haemoglobin for those who required a transfusion was 11.85g/dl compared to 13.6g/dl for those who did not (p < 0.001). Being obese or morbidly obese did not significantly prolong the LOS (p = 0.95). In conclusion, this study highlights significant patient characteristics which are associated with a prolonged LOS following TKR. The relatively low pre-operative haemoglobin in patients requiring a blood transfusion is a potential target for reducing the LOS

The effects of the method of fixation and interface conditions on the biomechanics of the femoral component of the Birmingham hip resurfacing arthroplasty were examined using a highly detailed three-dimensional computer model of the hip. Stresses and strains in the proximal femur were compared for the natural femur and for the femur resurfaced with the Birmingham hip resurfacing. A comparison of cemented versus uncemented fixation showed no advantage of either with regard to bone loading. When the Birmingham hip resurfacing femoral component was fixed to bone, proximal femoral stresses and strains were non-physiological. Bone resorption was predicted in the inferomedial and superolateral bone within the Birmingham hip resurfacing shell. Resorption was limited to the superolateral region when the stem was not fixed. The increased bone strain observed adjacent to the distal stem should stimulate an increase in bone density at that location. The remodelling of bone seen during revision of failed Birmingham hip resurfacing implants appears to be consistent with the predictions of our finite element analysis.