This study assesses oxidation, mechanical behavior and revision reasons of 2nd generation HXLPE used in total hip and knee arthroplasty. While oxidation was low for both X3 and E1 HXLPEs, oxidative regional variations were detected in the sequentially annealed cohort. First generation highly crosslinked polyethylenes (HXPLEs) have proven successful in lowering both penetration and osteolysis rates. However, 1st generation annealing and remelting thermal stabilization have been associated with in vivo oxidation or reduced mechanical properties. Thus, 2nd generation HXLPEs were developed to improve oxidative stability while still maintaining material properties. Little is known about the in vivo clinical failure modes of these 2nd generation HLXPEs. The purpose of this study was to assess the revision reasons, wear, oxidative stability, and mechanical behavior of retrieved sequentially annealed Vitamin E diffused HXLPE in THA and TKA.Summary Statement
Introduction
Fretting and corrosion has been identified as a clinical problem in modular metal-on-metal THA, but remains poorly understood in modern THA devices with polyethylene bearings. This study investigates taper damage and if this damage is associated with polyethylene wear. Degradation of modular head-neck tapers was raised as a concern in the 1990s (Gilbert 1993). The incidence of fretting and corrosion among modern, metal-on-polyethylene and ceramic-on-polyethylene THA systems with 36+ mm femoral heads remains poorly understood. Additionally, it is unknown whether metal debris from modular tapers could increase wear rates of highly crosslinked PE (HXLPE) liners. The purpose of this study was to characterise the severity of fretting and corrosion at head-neck modular interfaces in retrieved conventional and HXLPE THA systems and its effect on penetration rates.Summary Statement
Introduction
Service industry metrics (the net promoter score) are being introduced as a measure of UK healthcare satisfaction. Lower limb arthroplasty, as a ‘service’, scores comparably with the most successful commercial organisations. Satisfaction with care is important to both the patient and the payer. The Net Promoter Score, widely used in the service industry, has been recently introduced to the UK National Health Service as an overarching metric of patient satisfaction and to monitor performance. This questionnaire asks ‘customers’ if they would recommend a service or products to others. Scores range from −100 (everyone is a detractor) to +100 (everyone is a promoter). In industry, a positive score is well regarded, with those over 50 regarded as excellent. Our aims were to assess net promoter scores for joint arthroplasty, to compare these scores with direct measures of patient satisfaction, and to evaluate which factors contributed to net promoter response.Summary Statement
Background
In our department, currently there is variation in the number of xrays that patients receive following ORIF of distal radius fractures. This audit investigated the use of xrays following ORIF of distal radius fractures. Patients were identified from daily trauma lists. Patients who had a primary ORIF or ORIF following failed conservative management were included in the study. PACS was used to identify the number of post-operative xrays performed. These were correlated with clinic letters to see if there was any change in management following xray review. Between July and November 2013, 102 patients were admitted with distal radius fracture. Of these, 35 (mean age:51 years) had an ORIF. Four were not followed-up in Scotland. Of the remaining 31 patients, eleven had one post-operative xray, seventeen had two and three had three xrays. Of the patients who had one xray, seven had the xray in the first three weeks, the rest at six weeks. Patients who had two xrays had an xray at two and 6 weeks. Of the three patients who had three xrays, two had comminuted fractures that required further CT investigation, one for a suspicion of an intra-articular screw, the other for possibility of non-union. The third patient had no apparent reason for requiring three xrays. Thus of the 31 patients in the study, 29 did not require any further investigations. The results show a variation in the frequency of post-operative xrays after fixation of distal radius fractures. In most cases the management plan was unchanged after plain xrays were undertaken. This suggests that a protocol driven approach to follow-up after fixation of distal radius fractures could reduce the burden on fracture clinic and radiology departments. We propose that unless indicated by intra-operative findings or post-operative concerns, patients should have xrays at the two week review appointment.
Many psychological factors have been associated with function after joint replacement. Personality is a stable pattern of responses to external conditions and stimuli. The aim of this study was to investigate the relationship between personality, joint function, and general physical in patients undergoing total hip (THR) and knee replacement (TKR). We undertook a prospective cohort study of 184 patients undergoing THA and 205 undergoing TKA. Personality was assesed using the Eysneck Personality Questionaire, brief version (EPQ-BV). Physical health was measured using the EuroQol (EQ-5D). Joint function was measured using the relevant Oxford Score. Outcomes were assessed at six months. Multivariable models were constructed. The stable introvert personality was most common. Unstable introverts had poorer pre-operative function with hip arthrosis, but not knee arthrosis. Personality was not directly associated with post-operative function – the only independent predictors were pre-operative function (p=0.002) and comorbidity (p<0.001). While satisfaction after TKR was associated with personality (p=0.026), there was no association after THR (p=0.453). The poorest satisfaction was in those with the unstable introvert personality type. Personality was a predictor of preoperative status. It did not have a direct association with postoperative status, but may have as preoperative function was the main predictor of postoperative function, personality may have had an indirect effect. Personality was also a predictor of satisfaction after TKR. This suggests that predicting satisfaction after knee replacement is more complex. Therefore certain patient may benefit from a tailored preoperative education to explore and manage expectations.
Expectations of patients requiring knee arthroplasty surgery have become higher than in the past, with more strain being put on modern prostheses by fitter and younger patients. The objective of this study was to analyse the survivorship of primary knee arthroplasties at a minimum of ten years, with end points of revision and death. Patients who had a total (TKA) or unicompartmental (UKA) knee arthroplasty performed at a university teaching hospital were identified from the local arthroplasty database. Electronic and operative records were analysed to determine parameters including operative indication, subsequent revision surgery, and patient mortality. Results were collated and analysed using PASW software. A total of 1023 patients were recruited, with 566 (55%) female and 457 (45%) male. Minimum follow up was 10.1 years, with an average of 12.1 years (S.D 0.87). 64.9% of patients were alive at follow up, with an average age of 79.7 years (S.D 8.7). 92.8% were operated on for osteoarthritis (OA), 6.6% for rheumatoid arthritis (RA) and 0.6% for other indications. Kaplan–Meier analysis estimated survival of 94% (S.D 0.008) at eleven years, with no statistical difference found in survivorship of knees operated on for OA or RA. Similarly no statistical difference was found between survivorship of UKA or TKA implants. Of those that died by follow up, 95.2% did so with their original implant. We conclude that both TKA and UKA offer a lasting solution for patients, with excellent outcomes achieved in both rheumatoid and osteoarthritic patients.
First generation highly crosslinked polyethylenes (HXPLEs) have proven successful in lowering both penetration and osteolysis rates. However, 1st generation annealing and remelting thermal stabilization have been associated with in vivo oxidation or reduced mechanical properties. Thus, 2nd generation HXLPEs were developed to improve oxidative stability while still maintaining material properties. Little is known about the in vivo clinical failure modes of these 2nd generation HLXPEs. The purpose of this study was to assess the revision reasons, wear, oxidative stability, and mechanical behavior of retrieved sequentially annealed Vitamin E diffused HXLPE in THA and TKA. 251 2nd Generation HXLPE hip and knee components were consecutively retrieved during revision surgeries and continuously analyzed in a prospective, IRB approved, multicenter study. 123 acetabular liners (Implanted 1.2y; Range 0–5.0y) and 117 tibial inserts (Implanted 1.6y; Range 0–5.8y) were highly crosslinked and annealed in 3 sequential steps (X3). Five acetabular liners (Implanted 0.6y; Range 0–2.0y) and six tibial inserts (Implanted 1.3y; Range 0.5–1.8y) were diffused with Vitamin E (E1). Patient information was collected from medical records (Table 1). Linear penetration of liners was measured using a calibrated digital micrometer (accuracy: 0.001 mm). Surface damage of tibial components was assessed using the Hood method. Thin sections were taken from the acetabular liners (along the superior/inferior axis) and the tibial components (along the medial condyle and central spine) for oxidation analysis and analyzed according to ASTM 2102. Mechanical behavior was assessed via the small punch test (ASTM 2183).Introduction:
Methods:
Degradation of modular head-neck tapers was raised as a concern in the 1990s (Gilbert 1993). The incidence of fretting and corrosion among modern, metal-on-polyethylene and ceramic-on-polyethylene THA systems with 36+ mm femoral heads remains poorly understood. Additionally, it is unknown whether metal debris from modular tapers could increase wear rates of highly crosslinked PE (HXLPE) liners. The purpose of this study was to characterize the severity of fretting and corrosion at head-neck modular interfaces in retrieved conventional and HXLPE THA systems and its effect on penetration rates. 386 CoCr alloy heads from 5 manufacturers were analyzed along with 166 stems (38 with ceramic femoral heads). Metal and ceramic components were cleaned and examined at the head taper and stem taper by two investigators. Scores ranging from 1 (mild) to 4 (severe) were assigned in accordance with the semi-quantitative method adapted from a previously published technique. Linear penetration of liners was measured using a calibrated digital micrometer (accuracy: 0.001 mm). Devices implanted less than 1 year were excluded from this analysis because in the short-term, creep dominates penetration of the head into the liner.Introduction:
Patients & Methods:
Previous studies regarding modular head-neck taper corrosion were largely based on cobalt chrome (CoCr) alloy femoral heads. Less is known about head-neck taper corrosion with ceramic femoral heads. We asked (1) whether ceramic heads resulted in less taper corrosion than CoCr heads; (2) what device and patient factors influence taper fretting corrosion; and (3) whether the mechanism of taper fretting corrosion in ceramic heads differs from that in CoCr heads.Background:
Questions/purposes:
Nerve damage is a complication of THA and TKA procedures. The incidence of subclinical nerve injury following arthroplasty is unknown. The aim was to determine the prevalence of asymptomatic nerve deficits in an arthroplasty population group, and the incidence of post-operative changes in nerve function. A Secondary aim was to identify the nature of any deficits. And the association between nerve deficits and history of backache. A non-randomised prospective series of patients undergoing lower limb arthroplasty for osteoarthritis were studied at a single hospital. The peroneal nerve was investigated using nerve conduction in forty patients. Twenty patients had upper limb testing to differentiate between a polyneuropathy or isolated lower limb neuropathy. Nerve function deficits were detected in the peroneal nerve in fifteen patients pre-operatively and fifteen post-operatively, of those twelve had A waves detected suggestive of a generalised neuropathy. Ten patients who had upper limb testing had a conduction defect (five had asymptomatic Carpal tunnel). There was a positive correlation between presence of post-operative deficit and age(r=0.389, p=0.013). A negative correlation was found for presence of post-operative A waves and BMI(r=−0.370, p=0.019). The prevalence of pre-operative subclinical peroneal neuropathy is much higher than expected in this group (37.5%) of arthroplasty patients. There is a strong correlation between presence of post-operative conduction abnormalities and age. There is no relationship between peripheral neuropathy and history of backache or residual post-operative deficit.
We aimed to review the outcome of Agility total ankle replacements carried out in our institution between 2002 and 2006. Follow-up consisted of clinical and radiological review pre-operatively, then at 6 weeks, 6 and 12 months, and annually until 10 years post op. Clinical review included the American Orthopaedic Foot and Ankle Score, satisfaction and pain scores. Case notes were reviewed to determine intra and post-operative complications. 30 arthroplasties were performed in 30 consecutive patients. Pre-operative diagnosis was rheumatoid arthritis(16), primary osteoarthritis(12) and post-traumatic osteoarthritis(2). After a mean follow up of 6.2 years (1.4–10.1), 4 patients had died, and 22 out of the remaining 24 were available for follow-up. Intra operative complications included lateral malleoli fracture(3) and superficial peroneal nerve injury(2). Post operative complications included 1 early death, but this was not related to the surgical procedure. Two patients developed deep infections of the prosthesis. One underwent removal of the implant; the other is on long term oral antibiotic therapy. One patient had delayed union of the syndesmosis and six patients had non-union. On clinical assessment, patients' AOFAS scores improved from mean 40.4 pre-op to 83.5 post-op (p<0.001). Radiological assessment of the tibial component revealed 25 (93%) patients had lucency in at least one zone in the AP radiograph. We found a relatively high level of re-surgery and complications following Agility total ankle replacement. A 7% revision rate is much higher than would be tolerated in knee or hip arthroplasty, but compares favourably to other studies of TAR. Despite radiological features which suggest loosening, the high rate of re-surgery and complications; patients are generally satisfied with the procedure, reporting lower levels of pain and improved function. Overall we feel that the Agility ankle is an acceptable alternative to ankle arthrodesis, however patients need to be warned of the risk of re-surgery.
Few doctors answer their bleep by stating who they are. Answering the phone in a formal manner is of utmost importance in the hospital setting especially by on-call teams who are normally referred patients by other specialties, general practitioners and in some cases by other hospitals. An audit to evaluate the internal hospital communication was completed. In the first part of this audit, junior doctors within the orthopaedic department at the RAH were bleeped. Doctors were expected to answer by initiating the conversation by stating (1) name, (2) department, (3) grade and (4) a greeting. A list of omissions was recorded. If the call went through switchboard, it was expected that the hospital name was stated. The second part of the audit extended to other specialties in the RAH as well as orthopaedic departments in hospitals within the Greater Glasgow and Clyde health board (NHS GGC). Forty-three bleeps were made to doctors of various grades over a period of two months. Nine bleeps (two from other hospitals) were not answered. Five doctors answered their bleep in full. Only twenty-one doctors stated their name whilst eleven stated their grade. In both instances the department was not necessarily stated. The results were similar between the different departments as well as between the seven hospitals offering an orthopaedic service within NHS GGC. Of the thirteen on-call doctors that were bleeped as an external call through switchboard, only one doctor stated the hospital name. This has implications since most hospitals within NHS GGC share a common switchboard. These results emphasise the need for a protocol within NHS GGC for a standard etiquette for intra and inter hospital communication to ensure that patient safety and confidentiality is safeguarded.
Sequentially annealed highly crosslinked polyethylenes (HXLPEs) were introduced in total knee replacement (TKR) starting in 2005 to reduce wear and particle-induced osteolysis. Few studies have reported on the clinical performance of HXLPE knees. In this study, we hypothesized that due to the reduced free radicals, sequentially annealed HXLPE would have lower oxidation levels than gamma inert-sterilized controls. 145 tibial components were retrieved at consecutive revision surgeries at 7 different surgical centers. 74 components were identified as sequentially annealed HXLPE (X3, Stryker) while the remainder (n = 71) were conventional gamma inert sterilized polyethylene. The sterilization method was confirmed by tracing the lot numbers by the manufacturer. The conventional inserts were implanted for 1.7 years (Range: 0.0–9.3 years), while the X3 components were implanted 1.1 years (Range: 0.0–4.5 years). Surface damage was assessed using the Hood method. Oxidation analysis was performed in accordance with ASTM 2102 following submersion in boiling heptane for 6 hours to remove absorbed lipids. 30 of the conventional and 29 of the HXLPE inserts were available for oxidation analysis.Introduction
Methods
Wear debris generation in metal-on-metal (MOM) total hip arthroplasty (THA) has emerged as a compelling issue. In the UK, clinically significant fretting corrosion was reported at head-taper junctions of MOM hip prostheses from a single manufacturer (Langton 2011). This study characterizes the prevalence of fretting and corrosion at various modular interfaces in retrieved MOM THA systems used in the United States. 106 MOM bearing systems were collected between 2003 and 2012 in an NIH-supported, multi-institutional retrieval program. From this collection, 88 modular MOM THA devices were identified, yielding 76 heads and 31 stems (22 modular necks) of 7 different bearing designs (5 manufacturers) for analysis. 10 modular CoCr acetabular liners and 5 corresponding acetabular shells were also examined. Mean age at implantation was 58 years (range, 30–85 years) and implantation time averaged 2.2 ± 1.8 years (range, 0–11.0 years). The predominant revision reason was loosening (n=52). Explants were cleaned and scored at the head taper, stem taper, proximal and distal neck tapers (for modular necks), liner, and shell interfaces in accordance with the semi-quantitative method of Goldberg et al. (2002).Introduction
Methods and Materials
The purpose of this multicenter study was to assess the oxidative stability, mechanical behavior, wear and reasons for revision of 2nd generation sequentially annealed HXLPE, X3, and compare it to 1st generation XLPE, Crossfire. We hypothesized that X3 would exhibit similar wear rates but lower oxidation than Crossfire. 182 hip liners were consecutively retrieved during revision surgeries at 7 surgical centers and continuously analyzed over the past 12 years in a prospective, multicenter study. 90 were highly crosslinked and annealed (Crossfire; Implanted 4.2±3.4 years, max: 11 years), and 92 were highly crosslinked and annealed in 3 sequential steps (X3; Implanted 1.2±1.5 years; max: 5 years). Oxidation was characterized in accordance with ASTM 2102 using transmission FTIR performed on thin sections (∼200μm) from the superior/inferior axis. Mechanical behavior was assessed via the small punch test (ASTM 2183).Introduction
Methods
We reviewed the outcome of Agility total ankle replacements carried out in our institution between 2002 and 2006. Follow-up consisted of clinical and radiological review pre-operatively, at 6 weeks, 6 and 12 months, and annually until 10 years post-op. Clinical review included the American Orthopaedic Foot and Ankle Score, satisfaction and pain scores. 30 arthroplasties were performed in 30 consecutive patients. Pre-operative diagnosis was rheumatoid arthritis (16), primary osteoarthritis (12) and post-traumatic osteoarthritis (2). After a mean follow up of 6.2 years (1.4–10.1), 4 patients had died, and 20 out of the remaining 24 were available for follow-up. Complications included lateral malleoli fracture (3), superficial peroneal nerve injury (2), one early death, unrelated to the surgical procedure, delayed syndesmotic union (1), non-union (6) and deep infection (2), of which one underwent removal of the implant; the other receives long-term oral antibiotics. AOFAS scores improved from mean 40.4 pre-op to 83.5 post-op (p<0.001). Radiological assessment revealed 25 (93%) patients had lucency in at least one zone in the AP radiograph. We found a relatively high level of re-surgery and complications following Agility total ankle replacement. A 7% revision rate is much higher than would be tolerated in knee or hip arthroplasty, but compares favourably to other studies of TAR. Despite radiological loosening, and the high rate of re-surgery and complications; patients are generally satisfied with the procedure, reporting lower levels of pain and improved function. Overall, we feel that the Agility ankle is an acceptable alternative to arthrodesis, however patients should be warned of the risk of re-surgery
We aimed to review the outcome of Agility total ankle replacements carried out in our institution between 2002 and 2006. Follow-up consisted of clinical and radiological review pre-operatively, then at 6 weeks, 6 and 12 months, and annually until 10 years post op. Clinical review included the American Orthopaedic Foot and Ankle Score, satisfaction and pain scores. Case notes were reviewed to determine intra and post-operative complications. 30 arthroplasties were performed in 30 consecutive patients. Pre-operative diagnosis was rheumatoid arthritis(16), primary osteoarthritis(12) and post-traumatic osteoarthritis(2). After a mean follow up of 6.2 years (1.4–10.1), 4 patients had died, and 22 out of the remaining 24 were available for follow-up. Intra operative complications included lateral malleoli fracture(3) and superficial peroneal nerve injury(2). Post operative complications included 1 early death, but this was not related to the surgical procedure. Two patients developed deep infections of the prosthesis. One underwent removal of the implant; the other is on long term oral antibiotic therapy. One patient had delayed union of the syndesmosis and six patients had non-union. On clinical assessment, patients' AOFAS scores improved from mean 40.4 pre-op to 83.5 post-op (p< 0.001). Radiological assessment of the tibial component revealed 25 (93%) patients had lucency in at least one zone in the AP radiograph. We found a relatively high level of re-surgery and complications following Agility total ankle replacement. A 7% revision rate is much higher than would be tolerated in knee or hip arthroplasty, but compares favourably to other studies of TAR. Despite radiological features which suggest loosening, the high rate of re-surgery and complications; patients are generally satisfied with the procedure, reporting lower levels of pain and improved function. Overall we feel that the Agility ankle is an acceptable alternative to ankle arthrodesis, however patients need to be warned of the risk of re-surgery.
Patient expectations and their fulfilment are an important factor in determining patient-reported outcome and satisfaction of hip (THR) and knee replacement (TKR). The aim of this prospective cohort study was to examine the expectations of patients undergoing THR and TKR, and to identify differences in expectations, predictors of high expectations and the relationship between the fulfilment of expectations and patient-reported outcome measures. During the study period, patients who underwent 346 THRs and 323 TKRs completed an expectation questionnaire, Oxford score and Short-Form 12 (SF-12) score pre-operatively. At one year post-operatively, the Oxford score, SF-12, patient satisfaction and expectation fulfilment were assessed. Univariable and multivariable analysis were performed. Improvements in mobility and daytime pain were the most important expectations in both groups. Expectation level did not differ between THR and TKR. Poor Oxford score, younger age and male gender significantly predicted high pre-operative expectations (p < 0.001). The level of pre-operative expectation was not significantly associated with the fulfilment of expectations or outcome. THR better met the expectations identified as important by patients. TKR failed to meet expectations of kneeling, squatting and stair climbing. High fulfilment of expectation in both THR and TKR was significantly predicted by young age, greater improvements in Oxford score and high pre-operative mental health scores. The fulfilment of expectations was highly correlated with satisfaction.
Unicompartmental knee replacements (UKRs) have inconsistent and variable survivorships reported in the literature. It has been suggested that many are revised for ongoing pain with no other mode of failure identified. Using a medial UKR with an all-polyethylene non-congruent tibial component from 2004–7, we noted a revision rate of 9/98 cases (9.2%) at a mean of 39 months. Subchondral sclerosis was noted under the tibial component in 3/9 revisions with well fixed implants, and the aim of this study was to investigate this as a mode of failure. 89 UKRs in 77 patients were investigated radiographically (at mean 50 months) and with SF-12 and Oxford Knee scores at mean follow up 55 months. Subjectively 23/89 cases (25%) had sclerosis under the tibial component. We describe a method of quantifying this sclerosis as a greyscale ratio (GSR), which was significantly correlated with presence/absence of sclerosis (p<0.001). Significant predictors of elevated GSR (increasing sclerosis) were female sex (p<0.001) and elevated BMI (P=0.010) on both univariate and multivariate analysis. In turn, elevated GSR was significantly associated with poorer improvement in OKS (p<0.05) at the time of final follow up. We hypothesise that this sclerosis results from repetitive microfracture and adaptive remodelling in the proximal tibia due to increased strain. Finite element analysis is required to investigate this further, but we suggest caution should be employed when considering all polyethylene UKR implants in older women and in those with BMI >35.
Up to 20% of patients are not satisfied with the outcome following total knee replacement (TKR), but little is known about the predictors of this dissatisfaction. This study investigated the pre- and post-operative predictors of dissatisfaction in a large cohort of patients undergoing TKR. We assessed 1217 consecutive patients undergoing TKR between 2006 and 2008 both preoperatively and six months after surgery, using the Short-form (SF)-12 health questionnaire and the Oxford Knee Score. Detailed co-morbidity information was also gathered. Satisfaction was measured at one year and 18.6% (226 of 1217) of patients were unsure or dissatisfied with their replacement, 81.4% (911 of 1217) were satisfied or very satisfied. Multivariate regression analysis was performed to identify independent predictors of dissatisfaction. Significant (p < 0.001) predictors of dissatisfaction at one year included the pre-operative SF-12 mental component score, the co-morbidities of depression and pain in other joints, and the six-month SF-12 score. The most significant independent predictor of dissatisfaction at 1 year was poor improvement in Oxford Knee Score pain element at 6 months. Patient expectations were highly correlated with satisfaction. Satisfaction following TKR is multifactorial. Managing patient expectations and mental health may reduce dissatisfaction rates. However, the most significant predictor of dissatisfaction is a painful total knee replacement.
