Introduction: Radiolucency in the DeLee and Charnley zone 1 of the acetabulum in the early post operative period is a strong predictor of long-term failure of the cemented acetabulum. There is a wide variety in the acetabular anatomy of patients presenting for total hip replacement. Zone 1 radiolucency is an indicator of the failure of penetration of cement into the relatively hard cortical bone encountered in zone 1. Cement penetration is achieved by adequate preparation, achieving containment and effective pressurisation. Aim: To use pre operative radiological measurements to predict the risk of radiolucency around the cemented acetabular component post operation. Hypotheses:. Dysplastic acetabuli are associated with a higher incidence of zone 1 radiolucency. Retroverted acetabuli are associated with a higher risk of zone 1 radiolucency. Radiolucencies progress in the early post operative period. Materials and Methods: A cohort of 300 patients undergoing cemented THR in our institution was identified. Radiographs performed on the patients pre operatively, post operatively, at first follow up (6 weeks to 3months) and follow up at 1 year were analysed. The following measurements of the native acetabulum were performed: Tonnis grade of osteoarthritis, Crowe grade of dysplasia, acetabular index of depth to width, ACM angle, peak to edge distance, acetabular index of weight bearing zone, centre-edge angle of Widberg, acetabular angle of Sharp, cross over sign and posterior wall sign to assess retroversion, acetabular inclination and anteversion angle. Post operative films were then assessed for the presence of zone 1 keyholes, incidence and degree of radiolucency, cup inclination and anteversion. Results: Patients with an acetabulum outside the normal range were more likely to have a post operative radiolucency. Radiolucency tended to progress with time. Zone 1 keyholes appeared to terminate this progression. Retroverted and steeply inclined acetabuli demonstrated a higher incidence of radiolucency. A large change in version from the native to prosthetic acetabulum was associated with an increased risk of radiolucency. Conclusion: Thorough pre operative radiological assessment of the acetabular anatomy allows us to predict patients at high risk of post operative radiolucency. Patients with unsuitable anatomy may be more appropriate for an alternative method of fixation or require different techniques of acetabular preparation or augmentation in order to reduce their risk of loosening of the acetabular component in the long term

Purpose: To identify associative factors for radiolucency (RL) under the tibial component following the Oxford unicompartmental arthroplasty (UKA), and to evaluate its effect on clinical outcome scores. Method: One hundred and sixty-one knees which had undergone primary Phase 3 medial Oxford UKA were included. Fluoroscopic radiography films were assessed at five years post-operatively for areas of tibial RL. The two groups of patients, with and without RL, were compared to. patients’ pre-operative demographics for age, weight, height, BMI,. intra-operative variables such as the operating surgeon (n=2), insert and component sizes,. post-operative varus/valgus deformity, and. clinical outcome, assessed by the change in Oxford knee (OKS) and Tegner (TS) scores, from before surgery to five-year post-operatively. Results: 101 (62%) knees were found to have tibial RL. All RL were categorised as physiological or they were < 1mm thick, with sclerotic margins and non-progressive. No statistical difference was found between knees with RL and those without, in terms of pre-operative demographics, intra- or post-operative factors, and clinical outcome scores (p> 0.1 in all variables). Discussion: Radiolucency (RL) under the tibial component is a common finding following the Oxford UKA. Many theories have been proposed to explain the cause of RL, such as poor cementing, osteonecrosis, micromotion, and thermal necrosis. However, the true aetiology and clinical significance remain unclear. We attempted to address this. We found no significant relationship between physiological RL, pre-operative demographics, intra-operative variables and clinical outcome scores in this study. Tibial RL remains a common finding following the Oxford UKA yet we do not know why it occurs but in the medium term, clinical outcome is not influenced by RL. In particular, it is not a sign of loosening. Physiological RL can therefore be ignored even if associated with adverse symptoms following the Oxford UKA

Introduction: Radiolucent lines (RLL) underneath the tibial component are common findings following the Oxford Uni-compartmental Knee Arthroplasty (OUKA)[1]. Many theories have been proposed to explain the cause of RLL, such as poor cementing, osteonecrosis, micromotion, and thermal necrosis, however, the true aetiology and clinical significance remain unclear. We undertook a retrospective study analysing the association between RLL and pre-operative, intra-operative factors, as well as clinical outcome scores.

Method: One hundred and sixty-one knees which had undergone primary Phase 3 medial Oxford OUKA were included in the study. Fluoroscopic radiography films were assessed at five years post-operatively for areas of tibial RLL. The presence of RLL was compared to

patients’ pre-operative demographics for age, weight, height, BMI,

Results: Of the 161 knees in the study, 126 (78%) were found to have tibial RLL. No statistical difference was found between knees with RLL and those without in terms of preoperative demographics, intra-operative factors, or clinical assessment criteria.

Discussion: No clear relationship between RLL, preoperative demographics, and intra-operative factors has been identified in this study. We conclude that tibial RLL following OUKA is a common finding but do not seem to affect medium term clinical outcome.

Introduction

Radiolucencies beneath the tibial component are well recognized in knee arthroplasty; the aetiology and significance are poorly understood. Non-progressive narrow radiolucencies with a sclerotic margin are thought not to be indicative of loosening. Factors which decrease the incidence of radiolucencies include cementless fixation and the use of pulse lavage. Leg/component alignment or BMI do not influence radiolucency. We are not aware of any studies that have looked at the effect of load type on radiolucency.

The Oxford domed lateral tibial component was introduced to decrease the bearing dislocation rate that was unacceptably high with the flat tibial tray. However, the introduction of the domed tibial component alters the forces transmitted through the implant-cement-bone interface. As the Oxford UKR uses a fully congruent mobile bearing, the forces transmitted through the interface with a flat tray are compressive, except for the effect of friction. However, with the domed tibial component shear forces are introduced. The aim of this study was to assess the prevalence of radiolucency beneath the previous flat design and the new domed tibial tray.

Purpose of Study

To assess the incidence of radiolucency in cemented and cementless Oxford unicompartmental knee replacement at two years.

Purpose

Although the use of stems in revision total knee arthroplasty (RTKA) enhances survival by improving the stability of implant, questions as to the optimal fixation method as well as the vertical extent of the cement, remain unanswered. This study aimed 1) to determine the correlation between the vertical extent of cement and implant loosening; and 2) to determine the minimum cementing extent for a stable implant in revision TKA with a hybrid technique.

Aims

Loosening of components after total knee arthroplasty (TKA) can be associated with the development of radiolucent lines (RLLs). The aim of this study was to assess the rate of formation of RLLs in the cemented original design of the ATTUNE TKA and their relationship to loosening.

Background: The principal cause of late failure of the cemented acetabular component is aseptic loosening. The acetabulum is a horse shoe of cortico-cancellous bone surrounding a cortical fovea. The cancellous bone becomes denser and less porous peripherally, limiting cement penetration. A radiolucent line in the DeLee and Charnley zone 1 of the acetabulum increases the risk of loosening of the acetabular component by 38.8 times. We propose that the use of 0.5cm keyholes in zone 1 decreases the incidence of zone 1 radiolucency.

Materials and Methods: Two contemporous cohorts of 100 patients were analysed for the incidence of zone 1 radiolucency on the first post operative film. In one cohort, zone 1 keyholes were used and in the other they were not. The films were analysed independently by two blinded investigators. The incidence, length and thickness of any radiolucency were recorded.

Results: The cohort of patients in which zone 1 keyholes were used demonstrated a 9% incidence of any zone 1 radiolucency, 8% were of 1mm width or greater and 2% involved 50% or more of the zone. In the cohort of patients in which zone 1 keyholes were not used the incidence of zone 1 radiolucency was 40% with 29% demonstrating a width of 1mm or greater and 12% affecting 50% or more of the zone.

Conclusions: The use of peripheral keyholes aids penetration of cement into the denser peripheral acetabular bone as demonstrated by decreased rates of post operative zone 1 radiolucency. This decrease in the incidence of early radiolucency should result in lower rates of subsequent loosening of the acetabular component.

Studies have reported stem subsidence without loosening in cemented polished tapered stems. And also, the initial radiolucency seen immediately after surgery at the bone-cement interface has decreased in some cases with polished tapered stem as time passed. The etiologies of these phenomena are not still elucidated. We made a comparative study on the relation between stem subsidence and the initial radiolucency in polished and rough surface stems.

Subjects were 42 hips of 38 cases and 36 hips of 31 cases received primary THA using a Collarless Polished Tapered (CPT) stem and a polymethylmethacrylate pre-coated (VerSys Cemented Plus) stem respectively. Three x-ray films taken within 2 months, at 6 months and a year after surgery were reviewed.

Stem subsidence was seen in 34 hips of 31 cases (81.0%) in the CPT group and averaged 0.72mm (range, 0–2.52mm) at a year after surgery. Decrease in the initial radiolucency was seen in 15 hips (35.7%) in the CPTgroup. Stem subsidence averaged 1.12mm (range, 0.46–2.52mm) and 0.48 mm(range, 0.00–1.91mm) in the cases with decrease in the initial radiolucency and in those without any change respectively. Stem subsidence was significantly greater in the cases with decrease in the initial radiolucency(P< 0.005). In the VerSys group, no stem subsidence was seen except in 1 case of mechanical failure with 0.65mm of subsidence. No decrease in the initial radiolucency was seen, either.

It has been reported that the decrease in the radiolucency as we showed was thought a dense appearance of cancellous bone by load transfer in other polished tapered stem. In this study, stem subsidence may have caused decrease in the initial radiolucency. It has a possibility that not only a dense appearance of cancellous bone but also cement creep caused decrease in the initial radiolucency.

Aims

This study reports updates the previously published two-year clinical, functional, and radiological results of a group of patients who underwent transfibular total ankle arthroplasty (TAA), with follow-up extended to a minimum of five years.

Introduction: Radiolucencies are frequently observed around joint replacements. Their signiþcance & etiology remain unclear. Aim: 1. To study radiolucency under tibial tray of Oxford UKA and correlate it to the clinical outcome. 2. To study implant migration using RSA and study the correlation between migration and radiolucency. Materials and Methods: Fifty consecutive patients cemented Oxford UKA with a minimum follow up of two years were studied. At 2 years precisely aligned radiographs were obtained and evaluated for presence and extent of radiolucency under the tibial tray. The patients were divided into two groups Ð those with (Group I) and those without presence of radiolucency under the tibial tray (Group II). All the patients were assessed using KSS. Patients had RSA marker balls inserted around the prosthesis at the time of index procedure. Using RSA, the degree and direction of implant movement was measured at 1 & 2 yrs post surgery. Results: A) There were 26 patients in group I and 24 in group II. Both the groups were well matched for age and sex distribution. There was no signiþcant difference between the two groups when various clinical scores were compared. Maximum width of radiolucency was 1.1 mm and the average width was 0.57 mm. B) RSA study: By 12 months, the tibial component had migrated signiþcantly distally (mean: 0.42 mm, S.D.: 0.15 mm) and anteriorly (mean: 0.47 mm, S.D. 0.27mm). No signiþcant migration occurred after 12 mths. There was no correlation between presence or extent of radiolucency and migration of the tibial component. Conclusion: There is no relationship at 2 years between radiolucency and clinical results. There is also no relationship between radiolucency and migration. Therefore radiolucencies of 1mm or less can be ignored

Introduction: Most unicompartmental knee replacements (UKRs) employ cement for fixation of the prosthetic components to the bone. The information in the literature about the relative merits of cemented and cementless UKR is contradictory, with some favouring cementless fixation while others favouring cemented fixation. There is concern about the radiolucency which frequently develops around the tibial component with cemented fixations. The exact cause of the occurrence of radiolucency is unknown but according to some, it may suggest suboptimal fixation.

Method: Following ethical approval, 62 patients with medial OA were randomised to receive either cemented (n=31) or cementless components (n=31). All patients underwent identical surgical procedure with either a cemented or cementless Oxford UKR. Patients were assessed clinically and radiologically. The x-rays were taken with an image intensifier (I.I.). The position of the I.I. was adjusted until it was perfectly aligned with the tibial bone-implant interface thereby allowing accurate assessment of presence and extent of the radiolucency.

Results: The patients in the two groups were well matched. There was no significant difference in the clinical scores between the two groups. The mean OKS for the cemented group was 40 (± 8.3) and 42 (± 4.6) for cementless group. Narrow radiolucent lines were seen at the bone-implant interfaces of 75% of the cemented tibial components; partial in 43% and complete in 32%. In the cementless implants, partial radiolucencies were seen in 7% and complete radiolucencies in none. The differences are statistically highly significant (p< 0.0001) and imply satisfactory bone ingrowth into the cementless implants.

Conclusions: The method of fixation influences the incidence of radiolucency. With identical designs, no patient with cementless components developed any complete radiolucency. The observation raises the question as to whether cementless rather than cemented components should be routinely used for UKR.

Press-fit cups have given excellent clinico-radiographical results. This is a retrospective clinico-radiographical study about the long term performance of pure Titanium cementless modular press-fit cups (FitekTM) having, on the outer surface, an oriented multilayer titanium mesh (SulmeshTM) with 65% porosity (average pore size=400–640 micron). The cup was implanted after underreaming the acetabulum by 2 mm. In the cup’s equatorial area there are two “fins” originary designed to improve rotational stability but actually representing two excellent primary mechanical stabilizers.

We have evaluated the first 100 consecutive cups implanted in 92 patients with an average FU of 9,7 years (range 9–11 years). All operations have ben performed by the two Senior Authors (PGM and RB). Regarding etiology, we had 43 Primary Arthritis, 37 Dysplastic Arthritis, 12 Osteonecrosis and 8 Post-traumatic Arthritis. results were evaluated with the Harris score. Radiographic evaluation was performed using AP and lateral x-rays pre-op. post-op and at the last follow-up.

We had 86 Excellent, 10 Good, 2 Fair and 2 Poor. The 2 Poor results were 2 aseptic loosenings of the stem

The Mann-Whitney nonparametric U test and the Kruskal-Wallis test showed that the survival rate of the 100 analyzed cups, after a mean follow-up of 9.7 years, was 100% (end point: revision for any cause)

Etiology was not statistically correlated with post-op score.

Nevertheless, dysplastic patients showed inferior results compared to arthritic patients in different parameters, as pain, limp, Range Of Motion (p < 0.05), putting socks and shoes (p < 0.05).

Our cups were intentionally implanted and radiographically appear in a fairly horizontal position (36.5° on average).

In 6 cases we could calculate an eccentricity of the metal heads proving bidimensional linear wear of the liner (average 0.265 mm / year). At the last follow-up we had 3 femoral osteolysis, while in the acetabular side radiolucent lines were present in 14 % of the cases, never progressive.

In no case we found a change of position of the cup.

FitekTM cementless cups gave excellent results at 10 years with complete stability and osteo-integration. Excellent primary mechanical stability was given by the rough surface (SulmeshTM) and by the two “fins” in the equatorial area.

Aims

Although the short stem concept in hip arthroplasty procedure shows acceptable clinical performance, we sometimes get unexplainable radiological findings. The aim of this retrospective study was to evaluate changes of radiological findings up to three years postoperatively, and to assess any potential contributing factors on such radiological change in a Japanese population.

Aims

This study aimed to determine the diagnostic performance of radiographic criteria to detect aseptic acetabular loosening after revision total hip arthroplasty (THA). Secondary aims were to determine the predictive values of different thresholds of migration and to determine the predictive values of radiolucency criteria.

A total of 397 hips were randomised to receive Metasul metal-on-metal (MoM), metal-on-conventional polyethylene (MoP) or ceramic-on-polyethylene (CoP) bearings using a cemented triple-tapered polished femoral component (MS-30). There were 129 MoM hips in 123 patients (39 male and 84 female, mean age 63.3 years (40.7 to 72.9)), 137 MoP hips in 127 patients (39 male and 88 female, mean age 62.8 years (24.5 to 72.7)) and 131 CoP hips in 124 patients (51 male and 73 female, mean age 63.9 years (30.6 to 73.8)). All acetabular components were cemented Weber polyethylene components with the appropriate inlay for the MoM articulation. Clinical evaluation was undertaken using the Harris hip score (HHS) and radiological assessments were made at two, five and seven years. The HHS and radiological analysis were available for 341 hips after seven years. The MoM group had the lowest mean HHS (p = 0.124), a higher rate of revision (p < 0.001) and a higher incidence of radiolucent lines in unrevised hips (p < 0.001). In all, 12 revisions had been performed in 12 patients: eight in the MoM group (four for infection, four for aseptic loosening, three in the MoP group (one each of infection, dislocation and pain) and one in the CoP group (infection).

Our findings reveal no advantage to the MoM bearing and identified a higher revision rate and a greater incidence of radiolucent lines than with the other articulations. We recommend that patients with a 28 mm Metasul MoM bearing be followed carefully.

Cite this article: Bone Joint J 2013;95-B:881–6.

The Cementless Oxford Unicompartmental Knee Replacement (OUKR) was developed to address problems related to cementation, and has been demonstrated in a randomised study to have similar clinical outcomes with fewer radiolucencies than observed with the cemented device. However, before its widespread use it is necessary to clarify contraindications and assess the complications. This requires a larger study than any previously published.

We present a prospective multicentre series of 1000 cementless OUKRs in 881 patients at a minimum follow-up of one year. All patients had radiological assessment aligned to the bone–implant interfaces and clinical scores. Analysis was performed at a mean of 38.2 months (19 to 88) following surgery. A total of 17 patients died (comprising 19 knees (1.9%)), none as a result of surgery; there were no tibial or femoral loosenings. A total of 19 knees (1.9%) had significant implant-related complications or required revision. Implant survival at six years was 97.2%, and there was a partial radiolucency at the bone–implant interface in 72 knees (8.9%), with no complete radiolucencies. There was no significant increase in complication rate compared with cemented fixation (p = 0.87), and no specific contraindications to cementless fixation were identified.

Cementless OUKR appears to be safe and reproducible in patients with end-stage anteromedial osteoarthritis of the knee, with radiological evidence of improved fixation compared with previous reports using cemented fixation.

Cite this article: Bone Joint J 2013;95-B:181–7.

This study aims to implement and assess the inter and intra-reliability of a modernised radiolucency assessment system; the Radiolucency In cemented Stemmed Knee (RISK) arthroplasty classification. Furthermore, we assessed the distribution of regions affected by radiolucency in patients undergoing stemmed cemented knee arthroplasty. Stemmed knee arthroplasty cases over 7-year period at a single institution were retrospectively identified and reviewed. The RISK classification system identifies five zones in the femur and five zones in the tibia in both the anteroposterior (AP) and lateral planes. Post-operative and follow-up radiographs were scored for radiolucency by four blinded reviewers at two distinct time points four weeks apart. Reliability was assessed using the kappa statistic. A heat map was generated to demonstrate the reported regions of radiolucency. 29 cases (63 radiographs) of stemmed knee arthroplasty were examined radiographically using the RISK system. Intra-reliability (0.83) and Inter-reliability (0.80) scores were both consistent with a strong level of agreement using the kappa scoring system. Radiolucency was more commonly associated with the tibial component (76.6%) compared to the femoral component (23.3%), and the tibial anterior-posterior (AP) region 1 (medial plateau) was the most affected (14.9%). The RISK classification system is a reliable assessment tool for evaluating radiolucency around stemmed knee arthroplasty using defined zones on both AP and lateral radiographs. Zones of radiolucency identified in this study may be relevant to implant survival and corresponded well with zones of fixation, which may help inform future research

Abstract. Introduction. Higher than expected rates of tibial loosening with the ATTUNE® total knee arthroplasty (TKA) implant has been reported. Component loosening can be associated with the development of radiolucency lines (RLL) and our study aim was to systematically assess the reported rates of these. Methodology. A systematic search was undertaken using the Cochrane methodology in four online databases. Identified studies were assessed and screened against predetermined inclusion criteria. Meta-analysis was conducted using a random-effects model. Results. Nine studies (n=2,727 TKAs) from 6,590 titles met the inclusion criteria: 1 Randomised Controlled Trial (n=74), 1 prospective cohort (n=200), 4 retrospective cohort (n=1,639), and 3 case-series (n=814). All used the 2013 ATTUNE® design. In meta-analysis: 8 studies (n=1,440 ATTUNE TKAs) reported an overall prevalence of 11% (95%CI: 6.4-18.3%) for medial tibia RLL; 7 studies (n=940) a 12.3% (95%CI: 4.0-32%) rate of any tibia RLL.; 5 studies (n=736) femoral RLL in 11% (95%CI: 7.2-106.5%) and 7 studies (n=896) any RLL in 20.7% (95%CI: 13.4-30.6%). Meta-analysis of 4 studies (n=1,036) comparing the ATTUNE® with another implant (PFC Sigma®, LCS®, or PERSONA®) showed a higher risk of medial tibia RLL (OR: 2.538; 95%CI: 1.397-4.611, P=0.002) and any RLL (OR: 2.725; 95%CI: 1.302-5.703, P=0.008) in the ATTUNE® group. Conclusions. The 2013 ATTUNE® TKA system is associated with high rates of radiolucency around the tibial and femoral components. Comparative studies suggesting these rates are more than double those of other systems. Radiolucency may be a herald of component loosening, therefore, close surveillance of this implant is recommended

Introduction: Loosening of the acetabular Implant after Total Hip Replacement (THR) is often associated with massive bone loss. Many different solutions to this problem have been reported. The implant we used in our series is a cementless cup that consists of two different modular components: the outer shell, with a caudal hook and 3 iliac wings, and the inner module that can be placed in 20° angulation, where the liner is inserted. Non-structural bone graft was used. Materials and Methods: From April 2002 to October 2004 24 patients were treated with this implant (age 70,7 years, 48–88). They had had zero to six prior surgeries. Indications were: Aseptic loosening (20), septic loosening (2), repetitive luxations(1), intraoperative acetabular fracture (1). Acetabular bone loss was intraoperatively graded using the DGOT classification. Paprosky Classification was used for preoperative radiological grading. Harris Hip Score (HHS) was used for clinical evaluation (preoperative scores were retrospectively ascertained from patients’ charts). For radiological follow up plain X-rays of the pelvis a.p. and targeted views of the cup were used. Radiolucency, osteolysis (around cup, caudal hook, screws), migration (medial, cranial) and dumping was noted and the results divided into 3 groups: stable (no migration) at risk (cranial or medial migr.), loosened (cranial and medial migr.). Results:18 Patients with implants in situ could be examined at an average follow up time of 18,3 months (3–30). (1died, 1 could not be reached, 2 did not want to come to fu, 2 explantations after infection). Average stay in hospital: 26 days, non weight bearing for av.: 9,8 weeks. Complications: 1 transient common peroneal nerve palsy, 1 luxation after 4 months (treated conservatively). HHS improved from 36,4 to 69,3 points (max. 100). Pain: 15,5 to 36,8 pts (max. 44). Activity of daily living:14,3 to 36,8pts (max. 47). Walking distance 3,6–5,8 pts (max.11). Radiological results (n=19, patient who died included in rad. FU): Radiolucency and osteolysis: Cup 5, hook 12, screws 10. Migration: medial:7 (all of those had medial bone defects), cranial:4, angulation > 4°:4 Outcome: stable: 11, at risk: 3, loosened 5 (1 died, 1 explanted, 3 control every 3 months). Conclusion: In our series the SPH Bicomponente does not provide sufficient postoperative stability to facilitate good ingrowth of bone graft. Loosening occurs especially in cases with medial bone defects where the cup has too little contact to pelvic bone. In these cases cemented cups or structural grafts might give better stability. ‘At risk’ patients show better clinical performance than one would expect from the radiological findings. A second follow up is starting recently with an average FU time of about 36 months