The National Institute for Clinical Excellence (NICE), in its “Guidance on the Selection of Prostheses for Primary Total Hip Replacement”, states that a revision rate of 10% or less at ten years should be regarded as the “benchmark” in the selection of prostheses for primary Total Hip Replacement (THR). This paper presents the results of such a study for primary Charnley THR. Methods: All patients undergoing primary Charnley THR during 1990 were prospectively registered with the Trent Regional Arthroplasty Study (TRAS). During 1990, 1198 Charnley THRs were performed on 1152 patients, under the care of 56 consultants, in 18 National Health Service and 6 private hospitals. The cohort contains 39.0% male and 61.0% female patients, with an average age at operation of 69.1years (21–103 years), 19.1% being less than 60 years. At 10 years all surviving patients at 5 years were registered with the ONS to ascertain living patients. These patients were contacted by letter to determine whether or not their THR had been revised. The status of the THR, for non-responding patients, was determined by contacting the patient’s GP through the Contractor Services Agency (CSA). The endpoint was defined as revision surgery to replace an original implant component. Results: At 10 years, the recipients of 438 THRs had died. The recipients of 89 THRs did not respond to the questionnaire at ten years. Implant status at ten years, in living patients was known for 671 of 760 (88.3%) THRs. The ten-year crude revision rate was 44 out of 1198 (3.7%) and cumulative survival rate was 95.5% (95% CI, 93.6% – 96.9%). Conclusion: This is the first study to assess the survivorship at 10 years for primary Charnley THRs performed in the ‘general setting’ of the NHS as opposed to specialist centres and shows a result well within the NICE benchmark.
The Department of Health and the Public Health Laboratory Service established the Nosocomial Infection National Surveillance Scheme (NINSS) in response to the need to standardise the collection of information about infections acquired in hospital. This would provide national data that could be used as a ‘benchmark’ by hospitals to measure their own performance. The definition of superficial incisional infection (skin and subcutaneous tissue), set by Centers of Disease Control (CDC), should meet at least one of the following criteria: I: Purulent drainage from the superficial incision. II: The superficial incision yields organisms from the culture of aseptically aspirated fluid or tissue, or from a swab, and pus cells are present. III: At least two of the following symptoms and signs of inflammation: pain or tenderness, localized swelling, redness or heat, and a. the superficial incision is deliberately opened by a surgeon to manage the infection, unless the incision is culture-negative or b. clinician’s diagnosis of superficial incisional infection. This study assessed the interobserver reliability of the superficial incisional infection criteria, set by the CDC, in current practice. The incisional site of 50 consecutive patients, who underwent elective primary joint arthroplasty (Hips &
Knees), were evaluated independently by four observers. The most significant results of the study I: All four observers achieved absolute agreement (kappa=1) for Purulent wound discharge and clinical diagnosis of wound infection. II: The four observers obtained good agreement for pain criteria (kappa=0.76, III: There was significant disagreement (fair to poor) between all four observers for the following criteria: Localized swelling (kappa=0.34), Redness (kappa=0.33) and tenderness (kappa = 0.05). This is the first study to assess the reliability of the criteria, as set by the CDC and recommended by NINSS, for the diagnosis of superficial incisional infection and shows the Criterion III is not reliable and we recommend it should be revised. Failure to do so could lead to inaccurate statistics regarding hospital wound infection and detrimental effect on hospital trusts in the setting of league table.
Cementless fixation for total knee arthroplasty (TKA) has been proposed as an alternative to cemented for several reasons, of which the most important is the possibility of increased survival. The purpose of this study was to compare the ten-year survival of TKA in a unique prospective randomised trial of cemented versus cementless fixation. A consecutive series of patients was randomised to undergo either cemented or cementless Press-Fit Condylar (PFC®) TKA. There were 219 patients (277 TKA) in the cemented group and 177 (224 TKA) in the cementless group. There were no significant differences in age, gender or diagnosis between the two groups. A single surgeon (PJG) performed or directly supervised all operations. The prosthesis used in all cases was the posterior-cruciate-retaining PFC® knee replacement system. Independent clinical review was performed at six months, annually until five years, and finally at ten years after surgery. Using revision surgery as the end-point, logrank analysis was used to compare the ten-year survival of the two groups. The mean interval of follow-up was 6.3 years (range, 2.0–11.7). At the last review, 104 patients (138 TKA) had died, without need for revision. All patients were traced and there was no loss to follow-up. In the cemented group, seven arthroplasties were revised; five for infection and two for exchange of polyethylene inserts. Ten-year survival was 96.5% (95% CI, 90.9–98.7%). In the cementless group, six arthroplasties were revised; three for aseptic loosening, one for infection, one for instability and one resizing for anterior knee pain. The ten-year survival was 96.6% (95% CI, 89.6–98.9%). There was no significant difference in the survival of the two groups. The long-term survival of cementless PFC® TKA is not significantly different from their cemented counterparts. The use of less expensive cemented implants, therefore, can make a significant impact on health resource planning.
To establish whether there were features present on the initial post-operative radiographs of total hip replacements (THR) predictive of aseptic loosening. Our data was derived from the Trent Regional Arthroplasty Study (TRAS) which is the only hip register of its kind in the country. The TRAS commenced in 1990 and has recorded clinical and operative details of all THRs in the region. Our current study was concerned with a cohort of grossly loose THRs, identified from the five-year follow up of those patients who had undergone THR in 1990. Our cohort are those which failed specifically due to aseptic loosening and comprises those revised or listed for revision as well as a number of previously undiagnosed cases. The post-operative radiographs were analysed, recording the following: (1) number, width and location (Gruen zone) of radiolucencies at both cement-bone and cement-prosthesis interfaces; (2) presence of stem-cortex contact; (3) width of the cement mantle in each Gruen zone; and (4) Barrack cementation grade. Occasionally, if the initial post-operative radiograph was of poor quality, then further information was gained from the next available ones (usually at six weeks) to improve accuracy. Comparisons were made with 60 control hips randomly generated from the same 1990 cohort but which had not failed. Chi-squared tests were used to test the probability of obtaining the observed data by chance and odds ratios were calculated to describe relative risk of failure for different risk factors. Hips with inadequate cementation grades (C and D) had a 9.5 times greater risk of failure compared to those with adequate cementation grades (A and B) [p<
0.0001]. We have demonstrated that the grade of cementation has a major effect on the probability of failure. This emphasises the importance of good cementing, which is particularly relevant in this era of clinical governance where there is greater accountability on the surgeon for adequate performance.
Cementation is an important part of arthroplasty operations. Recent publication of results of Charnley total hip replacement found a rate of early aseptic loosening of 2.3% at 5 years following surgery across a NHS region. There are possibly many reasons for early loosening but precise reasons are still not fully understood, however, it is felt that cementation technique is very important. There seems to be a number of factors involved such as cement mixing techniques and conditions, physical properties of the cement, cementation and surgical techniques, bone-cement interface as well as bone- prosthesis interface. The purpose of this study was to evaluate the effectiveness of the clinical environment in producing bone cement of predictable mechanical and physical properties, and how those properties compare with published data. The investigation compared samples of bone cement, taken from material prepared and used in surgery with cement samples prepared under controlled laboratory conditions and in accordance with ISO materials testing standards. During 2000–01, 10 total hip replacements were selected for study. All operations involved the use of CMW1 (DePuy) radio-opaque cement, which was mixed using the Vacumix system. In this cohort, all femoral cementations were performed using an 80g cement mix. After careful preparation of the femoral canal, the scrub nurse mixed the cement in accordance with the manufacturer’s instructions. The cement was introduced into the femoral canal, via a nozzle, using the cementation gun and a pressurizer. Following introduction of cement into the canal, the nozzle and cement contained within, was broken off the gun distal to the pressurizer. Once cured, the cement samples were removed from the nozzle, sectioned, and mechanically tested. Due to this novel sample preparation procedure, the tested cement was expected to exhibit mechanical and physical properties characteristic of the cement present in the femoral canal. Samples of CMW1 (Vacumixed) of similar mass and aspect ratio were produced within the laboratory, in accordance with the manufacturers mixing instructions. PMMA bone cement is a brittle, glassy polymer that is susceptible to stress raisers, such as pores, which can reduce the load carrying ability, which The surgical samples were found to be very consistent in compressive strength (121 ± 6 MPa), density (1.20 ± 0.02 gcm−3) and hardness (23.2 ± 1.6 VHN) and closely matched the mechanical properties of the cement mixed in the laboratory. This study suggests that for the studied cement and mixing regime, the clinical environment is capable of producing a well-controlled cement product that has reproducible and predictable mechanical properties. Further, the novel sample preparation procedure used suggests that the cement within the femoral cavity should demonstrate equally predictable, mechanical and physical properties.
The early diagnosis of aseptic loosening of a total hip replacement by plain radiography, scintigraphy and arthrography has been shown to be unreliable. It has been suggested that it may be possible to distinguish between a secure and a loose prosthesis using a vibration technique. We have assessed the use of this technique in vitro using models of early and late loosening. Late loosening with an unstable prosthesis can be reliably detected by vibration analysis, but this method was shown to have a very poor diagnostic sensitivity in early loosening when there is no obvious prosthetic instability.
We report a randomised prospective trial of the early results of three types of treatment for displaced intracapsular hip fractures. We used a questionnaire sent to patients at about six months (Nottingham Health Profile, NHP) in addition to clinical assessments. There was a 67.4% usable response to the questionnaire, similar to that in other studies using the NHP. There were more responders from younger patients, those walking independently before injury and those with higher mental test scores on admission. In the younger group (65 to 79 years) we found a trend for better scores in most NHP indices after the use of a bipolar prosthesis rather than a unipolar prosthesis or internal fixation, particularly for social function, pain and physical mobility. Postal assessment using the NHP gave a satisfactory response rate even in the elderly, and can provide an extra assessment to complement or replace hospital follow-up in some circumstances.
We compared the reoperation rate after internal fixation for minimally displaced or impacted intracapsular fractures of the femoral neck in patients aged 80 years and above with that in similar patients aged 65 to 79 years. We also compared the results of internal fixation with those of hemiarthroplasty for displaced intracapsular fracture in an age- and sex-matched group of elderly patients. We found that a significantly greater proportion of the older patients treated by internal fixation required reoperation than either the younger group or the age-matched group treated by hemiarthroplasty. Our results indicate that internal fixation may not be the best treatment for extremely elderly patients with minimally displaced or impacted intracapsular fractures of the femoral neck.
We report a prospective trial of 66 patients with intraarticular fractures of the calcaneum. All fractures were assessed by CT. Patients with displaced fractures were randomised to receive either conservative (n = 31) or operative treatment (n = 25). Undisplaced fractures (n = 10) were treated conservatively. Operation involved open reduction of the posterior subtalar joint, and fixation with Kirschner wires. All 66 patients were reviewed at a minimum of one year (mean 23 months). After conservative treatment the undisplaced fractures had slightly better results than the displaced fractures. There was no significant difference in outcome between the operatively and the conservatively treated displaced fractures. We have also documented prospectively the natural history of the injury, which is of use in assessing prognosis for both clinical and medicolegal purposes.
We report the results of a randomised trial to determine the effects of skin traction on 252 patients awaiting surgery for fractures of the proximal femur. They were allocated randomly to be nursed free in bed or to receive Hamilton-Russell skin traction. No differences were found between the groups in terms of pain suffered, analgesia required, frequency of pressure sores or ease of operation. The application of skin traction to patients with fractures of the upper femur is time-consuming and we recommend therefore that its routine use should be discontinued.
The changes in serum adjusted ionised calcium and parathyroid hormone (PTH) were prospectively studied in 32 patients with isolated tibial fractures, treated conservatively. We measured serum albumin, adjusted total calcium, phosphate, pH, adjusted ionised calcium and PTH at intervals until the fractures had healed. The mean ionised calcium adjusted for pH fell within 24 hours of injury, and then rose to a peak at between four and six weeks. These changes cannot be explained by changes in serum pH or PTH. The restoration of normal ionised calcium levels after fracture coincided with the period when the callus was being calcified. Analysis of the changes in ionised calcium, phosphate and PTH suggests that PTH levels alter in response to changes in ionised calcium levels. PTH is highest immediately after fracture and lowest, often not recordable, at six weeks. The cause of the changes in the ionised calcium level has yet to be elucidated.
We have studied the incidence of fractures of the proximal femur in one English county from 1968 to 1991. Numbers have increased steadily, but the age-specific incidence has remained relatively unchanged since 1981. The increase is due to the rise in the population most at risk; this is likely to continue causing a 20% increase in demand for treatment by the year 2000. Suitable allocation of resources must be planned.
We have studied the radiographic and CT features of 120 displaced intra-articular fractures of the calcaneum in order to define the pathological anatomy. In 96% of cases, the CT scans identified three main fragments: sustentacular, lateral joint and body. The sustentacular fragment was often rotated into varus, the lateral joint fragment into valgus and the body fragment impacted upwards, in varus and displaced laterally. The displacement of these fragments varied according to which of three fracture types was present, as defined by the composition of the fractured lateral wall of the calcaneum. In type 1 it was formed by the lateral joint fragment alone; in type 2 by both body and lateral joint fragments; and in type 3 by the body fragment alone. Fracture fragment displacement differs from that previously described, in that true uniform depression of the lateral joint fragment is rare.
We studied the changes in plasma viscosity and C-reactive protein to establish normal values after total hip or knee arthroplasty. Viscosity decreased from 1.68 (+/- 0.017) to 1.57 (+/- 0.014) on the first postoperative day and thereafter rose to 1.60 (+/- 0.019), 1.75 (+/- 0.015), and 1.74 (+/- 0.011) on the third, seventh and fourteenth days respectively. Six to eight weeks after operation it had returned to pre-operative levels. A viscosity above the upper limit of the laboratory range, obtained more than two months after operation, may be considered as abnormal. The C-reactive protein level increased significantly on the first postoperative day and then decreased from a peak on the second day, attaining nearly normal levels at six to eight weeks after operation. It may be a more sensitive indicator of deep postoperative infection than plasma viscosity.
We measured pressures in the anterior and deep posterior compartments continuously for up to 72 hours in 20 patients with closed fractures of the tibial shaft treated primarily in plaster casts. All were examined independently after periods of three to 14 months. Pressures above 40 mmHg occurred in seven (35%) and above 30 mmHg in 14 (70%). No patient had the symptoms of compartment syndrome during monitoring. Abnormalities at review did not correlate with the maximum consecutive time periods during which the compartment pressures were raised. Thus, in the absence of symptoms the monitored pressures did not relate to outcome. Routine monitoring in this type of patient is therefore of doubtful benefit.
Immobilisation of the thumb is widely believed to be important in the management of fractures of the carpal scaphoid. To assess the need for this, we randomly allocated 392 fresh fractures for treatment by either a forearm gauntlet (Colles') cast, leaving the thumb free, or by a conventional 'scaphoid' plaster incorporating the thumb as far as its interphalangeal joint. In the 292 fractures which were followed for six months, the incidence of nonunion was independent of the type of cast used.
