Controversy persists over whether cemented or uncemented fixation is more effective in reducing revision and mortality risks following primary total hip arthroplasty (THA). Despite a shift towards uncemented THA in Europe, Australia, and the US, no consensus exists on superior outcomes. This ambiguity in evidence from randomized controlled trials (RCTs) and observational studies necessitates advanced research methodologies to derive more definitive conclusions. This study investigates the causal impact of THA fixation type on 2-year and 5-year revision rates, along with 90-day mortality, utilizing a regression discontinuity (RD) design in scenarios where fixation choice is guided by patient age. Employing data from the Dutch Arthroplasty Register, we conducted a cohort study on primary THAs for osteoarthritis from 2007 to 2019. A “fuzzy” RD design was executed to compute the Local Average Treatment Effect for subjects around the age-based selection threshold for fixation type. The main outcome of interest was the revision rate at 2 years post-operation. Analysis for the 2-year revision endpoint, covering any cause, included 2,344 females and 1,671 males across 5 hospitals each, with no significant variation in revision rates observed. For the 5-year mark, 1,058 females in 3 hospitals and 214 males in 1 hospital were examined, similarly showing no significant differences. Mortality within 90 days post-operation was also investigated in 5 female and 7 male cohorts, with 2,180 and 2,145 surgeries respectively, yielding no substantial disparities. In conclusion, the RD analysis revealed no notable differences in revision rates at 2 and 5 years or in early mortality based on the fixation method used in THA. These outcomes suggest that the age-based preference for THA fixation may not influence the revision or mortality risk, underscoring the value of RD design in deriving causal insights from observational data.
The aim of this study was to report the long-term follow-up of cemented short Exeter femoral components when used in primary total hip arthroplasty (THA). We included all primary 394 THAs with a cemented short Exeter femoral component (≤ 125 mm) used in our tertiary referral centre between October 1993 and December 2021. A total of 83 patients (21%) were male. The median age of the patients at the time of surgery was 42 years (interquartile range (IQR) 30 to 55). The main indication for THA was a childhood hip disease (202; 51%). The median follow-up was 6.7 years (IQR 3.1 to 11.0). Kaplan-Meier survival analyses were performed to determine the rates of survival with femoral revision for any indication, for septic loosening, for fracture of the femoral component and for aseptic loosening as endpoints. The indications for revision were evaluated. Fractures of the femoral component were described in detail.Aims
Methods
Although data on uncemented short stems are available, studies on cemented short-stemmed THAs are limited. These cemented short stems may have inferior long-term outcomes and higher femoral component fracture rates. Hence, we examined the long-term follow-up of cemented short Exeter stems used in primary THA. Within the Exeter stem range, 7 stems have a stem length of 125 mm or less. These stems are often used in small patients, in young patients with a narrow femoral canal or patients with anatomical abnormalities. Based on our local database, we included 394 consecutive cemented stems used in primary THA (n=333 patients) with a stem length ≤125 mm implanted in our tertiary referral center between 1993 and December 2021. We used the Dutch Arthroplasty Registry (LROI) to complete and cross-check the data. Kaplan-Meier survival analyses were performed to determine 20-year survival rates with stem revision for any reason, for septic loosening, for aseptic loosening and for femoral component fracture as endpoints. The proportion of male patients was 21% (n=83). Median age at surgery was 42 years (interquartile range: 30–55). The main indication for primary THA was childhood hip diseases (51%). The 20-year stem survival rate of the short stem was 85.4% (95% CI: 73.9–92.0) for revision for any reason and 96.2% (95%CI: 90.5–98.5) for revision for septic loosening. No stems were revised for aseptic femoral loosening. However, there were 4 stem fractures at 6.6, 11.6, 16.5 and 18.2 years of follow-up. The stem survival with femoral component fracture as endpoint was 92.7% (CI: 78.5–97.6) at 20 years. Cemented short Exeter stems in primary THA show acceptable survival rates at long-term follow-up. Although femoral component fracture is a rare complication of a cemented short Exeter stem, orthopaedic surgeons should be aware of its incidence and possible risk factors.
To map literature on prognostic factors related to outcomes of revision total knee arthroplasty (rTKA), to identify extensively studied factors and to guide future research into what domains need further exploration. We performed a systematic literature search in MEDLINE, Embase, and Web of Science. The search string included multiple synonyms of the following keywords: "revision TKA", "outcome" and "prognostic factor". We searched for studies assessing the association between at least one prognostic factor and at least one outcome measure after rTKA surgery. Data on sample size, study design, prognostic factors, outcomes, and the direction of the association was extracted and included in an evidence map.Aims
Methods
This study aimed to investigate the estimated change in primary and revision arthroplasty rate in the Netherlands and Denmark for hips, knees, and shoulders during the COVID-19 pandemic in 2020 (COVID-period). Additional points of focus included the comparison of patient characteristics and hospital type (2019 vs COVID-period), and the estimated loss of quality-adjusted life years (QALYs) and impact on waiting lists. All hip, knee, and shoulder arthroplasties (2014 to 2020) from the Dutch Arthroplasty Register, and hip and knee arthroplasties from the Danish Hip and Knee Arthroplasty Registries, were included. The expected number of arthroplasties per month in 2020 was estimated using Poisson regression, taking into account changes in age and sex distribution of the general Dutch/Danish population over time, calculating observed/expected (O/E) ratios. Country-specific proportions of patient characteristics and hospital type were calculated per indication category (osteoarthritis/other elective/acute). Waiting list outcomes including QALYs were estimated by modelling virtual waiting lists including 0%, 5% and 10% extra capacity.Aims
Methods
The aim of this study is to report the long-term outcomes of instrumented femoral revisions with impaction allograft bone grafting (IBG) using the X-change femoral revision system at 30 years after introduction of the technique. We updated the outcomes of our previous study, based on 208 consecutive revisions using IBG and the X-change femoral revision system in combination with a cemented polished stem, performed in our tertiary care institute between 1991 and 2007. Kaplan-Meier survival analyses were used to determine the survival rate of the revisions with endpoint revision for any reason and aseptic loosening. Secondary outcomes were radiological loosening and patient-reported outcome measures.Aims
Methods
The aim of this study was to determine the outcome of all primary total hip arthroplasties (THAs) and their subsequent revision procedures in patients aged under 50 years performed at our institution. All 1,049 primary THAs which were undertaken in 860 patients aged under 50 years between 1988 and 2018 in our tertiary care institution were included. We used cemented implants in both primary and revision surgery. Impaction bone grafting was used in patients with acetabular or femoral bone defects. Kaplan-Meier analyses were used to determine the survival of primary and revision THA with the endpoint of revision for any reason, and of revision for aseptic loosening.Aims
Methods
Preoperative nasal All primary total hip arthroplasties (THA) and total knee arthroplasties (TKA) performed from January 2006 to April 2018 were retrospectively reviewed for the incidence of early PJI. Demographic parameters, risk factors for PJI (American Society of Anaesthesiologists classification, body mass index, smoking status, and diabetes mellitus) and implant types were collected. A preoperative screening and eradication protocol for nasal colonization of Aims
Methods
The aim of this study was to analyze the effect of a lateral rim mesh on the survival of primary total hip arthroplasty (THA) in young patients, aged 50 years or younger. We compared a study group of 235 patients (257 hips) who received a primary THA with the use of impaction bone grafting (IBG) with an additional lateral rim mesh with a group of 306 patients (343 hips) who received IBG in the absence of a lateral rim mesh during the same period from 1988 to 2015. In the mesh group, there were 74 male and 183 female patients, with a mean age of 35 years (13 to 50). In the no-mesh group, there were 173 male and 170 female patients, with a mean age of 38 years (12.6 to 50). Cox regression analyses were performed to study the effect of a lateral rim mesh on acetabular component survival. Kaplan–Meier analyses with 95% confidence intervals (CIs) were performed to estimate the survival of the acetabular implant.Aims
Patients and Methods
We carried out a further study of the long-term results of the
cemented Exeter femoral component in patients under the age of 40
with a mean follow-up of 13.6 years (10 to 20). We reviewed our original cohort of 104 cemented Exeter stems
in 78 consecutive patients with a mean age of 31 years (16 to 39).
Only one patient was lost to radiological follow-up.Aims
Patients and Methods
Recent reports implicate fretting corrosion at the head-stem taper junction as a potential cause of failure of some large diameter metal-on-metal (MOM) devices. Fretting observed at modular junctions is thought to be a type of ‘mechanically assisted’ corrosion phenomenon, initiated by mechanical factors that lead to an increase in contact stresses and micromotions at the taper interface. These may include: intra-operative taper assembly, taper contamination by debris or body fluids, patient weight and ‘toggling’ of the head or increased frictional torque in a poorly functioning bearing. We adopted a finite element approach to model the head-taper junction, to analyze the contact mechanics at the taper interface. We investigated the effect of assembly force and angle on contact pressures and micromotions, during loads commonly used to test hip implants. Models of the Biomet Type-1 taper, a 60 mm head and a taper adaptor were created. These models were meshed with a mesh size based on a mesh density convergence study. Internal mesh coarsening was applied to reduce computational cost. Elastic-plastic material properties based on tensile tests were assigned to all titanium components. The contact conditions used in the FE analyses were validated against push-on and pull-off experiments, resulting in a coefficient of friction of 0.5. To analyze micromotions at the taper-adaptor connection, the models were loaded with 2300N (ISO 7206-4) and 5340N (ISO 7206-6), after being assembled with 2-4-15 kN, axially and under a 30º angle. This ISO standard is commonly used to determine endurance properties of stemmed femoral components. Micromotions and contact pressures were analyzed by scoring them to an average micromotion and average contact pressure for the surface area in contact.Introduction
Materials and methods
We present the results of 62 consecutive acetabular
revisions using impaction bone grafting and a cemented polyethylene
acetabular component in 58 patients (13 men and 45 women) after
a mean follow-up of 27 years (25 to 30). All patients were prospectively
followed. The mean age at revision was 59.2 years (23 to 82). We performed Kaplan–Meier (KM) analysis and also a Competing
Risk (CR) analysis because with long-term follow-up, the presence
of a competing event (i.e. death) prevents the occurrence of the
endpoint of re-revision. A total of 48 patients (52 hips) had died or had been re-revised
at final review in March 2011. None of the deaths were related to
the surgery. The mean Harris hip score of the ten surviving hips
in ten patients was 76 points (45 to 99). The KM survivorship at 25 years for the endpoint ‘re-revision
for any reason’ was 58.0% (95% confidence interval (CI) 38 to 73)
and for ‘re-revision for aseptic loosening’ 72.1% (95% CI 51 to
85). With the CR analysis we calculated the KM analysis overestimates
the failure rate with respectively 74% and 93% for these endpoints.
The current study shows that acetabular impaction bone grafting
revisions provide good clinical results at over 25 years. Cite this article:
We report the clinical and radiographic outcomes
of 208 consecutive femoral revision arthroplasties performed in 202
patients (119 women, 83 men) between March 1991 and December 2007
using the X-change Femoral Revision System, fresh-frozen morcellised
allograft and a cemented polished Exeter stem. All patients were
followed prospectively. The mean age of the patients at revision
was 65 years (30 to 86). At final review in December 2013 a total
of 130 patients with 135 reconstructions (64.9%) were alive and
had a non re-revised femoral component after a mean follow-up of
10.6 years (4.7 to 20.9). One patient was lost to follow-up at six
years, and their data were included up to this point.
Re-operation for any reason was performed in 33 hips (15.9%), in
13 of which the femoral component was re-revised (6.3%). The mean
pre-operative Harris hip score was 52 (19 to 95) (n = 73) and improved
to 80 (22 to 100) (n = 161) by the last follow-up. Kaplan–Meier
survival with femoral re-revision for any reason as the endpoint
was 94.9% (95% confidence intervals (CI) 90.2 to 97.4) at ten years;
with femoral re-revision for aseptic loosening as the endpoint it was
99.4% (95% CI 95.7 to 99.9); with femoral re-operation for any reason
as the endpoint it was 84.5% (95% CI 78.3 to 89.1); and with subsidence ≥ 5
mm it was 87.3% (95% CI 80.5 to 91.8). Femoral revision with the
use of impaction allograft bone grafting and a cemented polished
stem results in a satisfying survival rate at a mean of ten years’ follow-up. Cite this article:
In this retrospective study, we investigated
the results of revision total hip replacement (THR) using a cemented long-stemmed
Exeter femoral component, with a minimum length of 205 mm in patients
with extensive femoral bone defects. The study included 37 consecutive
patients with a mean age of 76 years (39 to 93) and a mean follow-up
of nine years (5 to 16). A total of 26 patients (70%) had a pre-operative
Endo-Klinik score of 3 or 4. Impaction bone grafting was used in
24 patients (65%). At the time of evaluation, 22 patients (59%)
were still alive and were evaluated clinically and radiologically.
A total of 14 patients died during follow-up and their data were
included until the time of their death. One reconstruction failed
after five years and five months owing to recurrent dislocation:
the hip was converted to an excision arthroplasty. Intra-operative
fractures or fissures were encountered in nine patients (24%), but
none occurred during impaction of the bone graft. Post-operative
peri-prosthetic fractures occurred in two patients (5%); both were
treated with plate fixation. At nine years, survival with the endpoint
of all-cause re-revision was 96.3% (95% CI 76.4 to 99.5); including
re-operations for any reason, it was 80.7% (95% CI 56.3 to 92.3%).
There were no re-revisions for aseptic loosening. The survival of long stem cemented femoral components following
revision THR is satisfactory in a fragile population with extensive
femoral defects. Cite this article:
Despite the worldwide usage of the cemented Contemporary
acetabular component (Stryker), no published data are available
regarding its use in patients aged <
50 years. We undertook a
mid- to long-term follow-up study, including all consecutive patients
aged
<
50 years who underwent a primary total hip replacement using
the Contemporary acetabular component with the Exeter cemented stem
between January 1999 and January 2006. There were 152 hips in 126
patients, 61 men and 65 women, mean age at surgery 37.6 years (16
to 49 yrs). One patient was lost to follow-up. Mean clinical follow-up of all implants was 7.6 years (0.9 to
12.0). All clinical questionnaire scores, including Harris hip score,
Oxford hip score and several visual analogue scales, were found
to have improved. The eight year survivorship of all acetabular
components for the endpoints revision for any reason or revision
for aseptic loosening was 94.4% (95% confidence interval (CI) 89.2
to 97.2) and 96.4% (95% CI 91.6 to 98.5), respectively. Radiological follow-up
was complete for 146 implants. The eight year survival for the endpoint
radiological loosening was 93.1% (95% CI 86.2 to 96.6). Three surviving
implants were considered radiologically loose but were asymptomatic.
The presence of acetabular osteolysis (n = 17, 11.8%) and radiolucent
lines (n = 20, 13.9%) in the 144 surviving cups indicates a need
for continued observation in the second decade of follow-up in order
to observe their influence on long-term survival. The clinical and radiological data resulting in a ten-year survival
rate >
90% in young patients support the use of the Contemporary
acetabular component in this specific patient group. Cite this article:
Recent reports have implicated fretting corrosion at the head-stem taper junction as a potential cause of failure of some large diameter metal-on-metal (MOM) devices. While it has been suggested that larger MOM heads, may induce greater frictional torques at the taper connection, the exact mechanisms underlying fretting corrosion remain poorly understood. It is likely that the onset of the corrosion process is caused by mechanical factors, such as contact stresses and micromotions occurring at the interface. These stresses and micromotions depend on the fixation of the head onto the stem and may be affected by blood, fat, bone debris or other contaminations. The fixation of the head is achieved intraoperatively through impaction. To further study this phenomenon, we adopted a finite element approach in which we modeled the head-taper junction fixation mechanics. In this model, we analyzed the effect of impaction force on the micromotions occurring at the head-stem interface. We created a model of a BIOMET Type-1 taper and an adapter that is typically used for larger heads. Titanium alloy material properties were assigned to both components, and frictional contact (μ = 0.5) was simulated between the adapter and the taper. To ensure that the model accurately represented the contact mechanics, we first simulated experiments in which the head was assembled on the taper in a load-controlled manner, at different load (4 and 15 kN), after which it was disassembled axially. The disassembly loads predicted by the FEA simulations were then compared to the experimental values. After ensuring a correct prediction of the disassembly loads, we used various impaction loads (2, 4, and 15 kN) to assemble the taper, after which a 2.3 kN load (ISO 7206-4) was applied to the adapter/taper assembly. This loading regime is commonly used to determine endurance properties of stemmed femoral components. Under these loading conditions, we then analyzed the contact stresses and micromotions, and the effect of impaction load on these quantities.Introduction
Materials and methods
These days, total hip arthroplasties (THA) are more implanted in young patients. Due to the expected lifespan of a THA and the life expectancy of young patients, a future revision is inevitable. Indirectly increasing the number of revisions in these patients. Therefore we evaluated the results of revision THA in patients under the age of 60 years. However, we used a unique protocol in which we used in all cases of acetabular and/or femoral bone deficiencies reconstruction with bone impaction grafting. To determine the mid- to longterm results of cemented revision total hip arthroplasties in patients under the age of 60, all clinical data and radiographs were analyzed of patients operated between 1992 and 2005. Patients with multiple previous revisions were also included. Only cemented components were used. During this period 146 consecutive revision total hip arthroplasties were implanted in 129 patients. This included 124 cup and 106 stem revisions. The average age at index surgery was 47 years. No case was lost. Mean follow-up was 7.6 (range, 2.0–16.7) years.Background
Methods
Total hip arthroplasties in younger patients often requires revision because these patients frequently have acetabular deficiencies, which hamper proper implantation of the cup essential for good long-term prosthesis survival. For 30 years, we have used a biological acetabular-reconstruction technique with bone-impaction grafting in all patients <50 years with an acetabular deficiency at surgery, always in combination with a cemented total hip implant. We evaluated all 150 consecutive patients (177 hips) < 50 years with an acetabular reconstruction by bone-impaction grafting surgically-treated from 1978–2004 at our clinic. Mean follow-up was 10.3 (range, 2.0–28.3) years with no patient lost to follow-up. Mean index surgery age was 38.1 (range, 16–49) years. Clinical, radiological, and statistical analysis of all patients was performed.Introduction
Methods
Surgeons always must take into account that a primary total hip arthroplasty (THA) in a young patient will be revised in the future, this because of the long life expectancy of young THA patients and the limited durability of prosthetic implants in these patients. Therefore we would like to accentuate the revisability of a primary THA in this specific and high demanding patient population. 343 consecutive THA in 267 patients under the age of 50 years were evaluated. We also assessed the results of the revised THA (n=53) within the same population. Clinical, radiographical and survival of primary and revision THA were evaluated.Background
Methods
The Kaplan-Meier estimation is widely used in orthopedics to
calculate the probability of revision surgery. Using data from a
long-term follow-up study, we aimed to assess the amount of bias
introduced by the Kaplan-Meier estimator in a competing risk setting. We describe both the Kaplan-Meier estimator and the competing
risk model, and explain why the competing risk model is a more appropriate
approach to estimate the probability of revision surgery when patients
die in a hip revision surgery cohort. In our study, a total of 62 acetabular
revisions were performed. After a mean of 25 years, no patients
were lost to follow-up, 13 patients had undergone revision surgery
and 33 patients died of causes unrelated to their hip.Objectives
Methods
Especially in young patients, total hip implants with proven long-term follow-up data should be used. Despite this, almost all patients under 30 years old will face a revision of their hip prosthesis during their life time because of their life expectancy. Therefore, all the used implants should be revisable with reliable outcome. Although, several studies have evaluated the outcome of different THA implants in patients under 30, only few report the long term follow-up of 10 years or more. None of them present the outcome of the revised total hips. We retrospectively reviewed prospectively collected data of 48 consecutive patients (69 hips), all received a cemented implant and in case of acetabular bone stock deficiency (29 hips), a reconstruction with bone impaction grafting (BIG) was performed. Mean age at surgery was 24.6 years (range, 16.0–29.0 years). Two patients were lost to follow-up. As far as we know, no revisions are performed in these two patients and their data are included in the study up to their last radiographic control. All failed hips were revised with again cemented implants and, if needed, bone impaction grafting. For the primary THA Kaplan-Meier survival curves at 10- and 15-year endpoint revision for any reason and revision for aseptic loosening were calculated. Separate survival rates at 10- and 15- year were calculated for the BIG group versus the non-BIG group. The outcome of the revised hips was studied and reported with re-revision as the endpoint.Introduction
Methods
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. Between 1988 and 2004, 69 consecutive primary cemented THAs (mainly Exeters) were performed in 48 patients (32 women, 16 men) younger than thirty years. Average age at time of operation was 25 years (range, 16 to 29 years). Twenty-nine hips (42%) underwent acetabular bone impaction grafting because of acetabular bone loss. Mean follow-up was 10 years (range, 2 to 18 years). Revisions were determined, Harris Hip Score (HHS), and Oxford Hip Questionnaire Score (OHQS) were obtained and radiographs were analyzed. Survival was calculated using the Kaplan-Meier method.Introduction
Methods
Also, five cefazolin and vancomycin solutions were used to impregnate bone chips and to make dose-response curves. Furthermore, 1 gram bone chips was impregnated with 5ml cefazolin or 5ml vancomycin solution.
We investigated the feasibility of using porous titanium particles (TiP) to reconstruct femoral bone defects in revision hip replacement surgery in stead of using morzelised bone grafts. Questions regarding handling, initial stability and titanium particle release were addressed. Seven composite femurs (Sawbones) were reamed and filled, stepwise, with 32 grams of large (Ø 3.15 – 4 mm) and 9 grams of smaller (Ø 2.8 – 3.15 mm) pure, 85% porous TiP. Subsequently an Exeter stem was cemented into the graft layer. All reconstructions were loaded axially (0–3000 N) for 300,000 loading cycles at 2 Hz. Subsidence of the stem was measured with radio stereometric analysis (RSA) and possible titanium particle release was measured using the laser diffraction technique. The TiP were impacted into a >
3 mm (SD 1.43 mm) thick, highly entangled, graft layer. An average cement mantle of >
2 mm (SD 0.86 mm) was measured and little cement penetration was observed. The average subsidence of only 0.45 mm (SD 0.04 mm) was measured after 300 000 loading cycles. Most titanium particles were found directly after impaction. Most of these particles (87%) were smaller than 10 μm and could therefore be potentially harmful since they can induce osteolysis. We can conclude that:
A graft layer of impacted TiP can be constructed, The graft layer is stable enough to initially support a cemented Exeter stem, Titanium particles are released during impaction. These data warrant further animal tests to assess the biological response to these released impaction particles. Also, animal tests should clarify possible particle release upon loading and its effects.
We present an update of the clinical and radiological results of 62 consecutive acetabular revisions using impacted morsellised cancellous bone grafts and a cemented acetabular component in 58 patients, at a mean follow-up of 22.2 years (20 to 25). The Kaplan-Meier survivorship for the acetabular component with revision for any reason as the endpoint was 75% at 20 years (95% confidence interval (CI) 62 to 88) when 16 hips were at risk. Excluding two revisions for septic loosening at three and six years, the survivorship at 20 years was 79% (95% CI 67 to 93). With further exclusions of one revision of a well-fixed acetabular component after 12 years during a femoral revision and two after 17 years for wear of the acetabular component, the survivorship for aseptic loosening was 87% at 20 years (95% CI 76 to 97). At the final review 14 of the 16 surviving hips had radiographs available. There was one additional case of radiological loosening and four acetabular reconstructions showed progressive radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.5 cm to 1 cm in diameter) and a cemented acetabular component remains a reliable technique for reconstruction, even when assessed at more than 20 years after surgery.
We evaluated the outcome of 104 consecutive primary cemented Exeter femoral components in 78 patients (34 men, 44 women) under the age of 40 years who underwent total hip replacement between October 1993 and May 2004. The mean age at operation was 31 years (16 to 39). No hip was lost to follow-up, but three patients (four hips) died. None of the deaths were related to the surgery. At a mean follow-up of 6.2 years (2 to 13), three femoral components had been revised for septic loosening. Using Kaplan-Meier survival analysis, the seven-year survival of the component with revision for any reason as the endpoint was 95.8% (95% confidence interval 86.67 to 98.7). The seven-year survival with aseptic femoral loosening as the endpoint was 100% (95% confidence interval 100). The cemented Exeter femoral component in patients under the age of 40 shows promising medium-term results. As it is available in a wide range of sizes and offsets, we could address all types of anatomical variation in this series without the need for custom-made components.
Allografts of bone from the femoral head are often used in orthopaedic procedures. Although the donated heads are thoroughly tested microscopically before release by the bone bank, some surgeons take additional cultures in the operating theatre before implantation. There is no consensus about the need to take these cultures. We retrospectively assessed the clinical significance of the implantation of positive-cultured bone allografts. The contamination rate at retrieval of the allografts was 6.4% in our bone bank. Intra-operative cultures were taken from 426 femoral head allografts before implantation; 48 (11.3%) had a positive culture. The most frequently encountered micro-organism was coagulase-negative staphylococcus. Deep infection occurred in two of the 48 patients (4.2%). In only one was it likely that the same micro-organism caused the contamination and the subsequent infection. In our study, the rate of infection in patients receiving positive-cultured allografts at implantation was not higher than the overall rate of infection in allograft surgery suggesting that the positive cultures at implantation probably represent contamination and that the taking of additional cultures is not useful.
This study presents the clinical and radiological results of 62 consecutive acetabular revisions in 58 patients, at a mean of 16.5 years follow-up (15 to 20). The Kaplan-Meier survivorship for the cup with end-point revisions for any reason, was 79% at 15 years (95% confidence interval (CI); 67 to 91). Excluding two revisions for septic loosening at three and six years, and one revision of a well-fixed cup after 12 years in the course of a femoral revision, the survivorship was 84% at 15 years (95% CI; 73 to 95). At review there were no additional cases of loosening, although seven acetabular reconstructions showed radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.7 cm to 1.0 cm) and a cemented cup, is a reliable technique of reconstruction, when assessed at more than 15 years.
The use of impacted, morsellised bone grafts has become popular in revision total hip arthroplasty (THA). The initial stability of the reconstruction and the effectiveness of any subsequent process of revitalisation and incorporation will depend on the mechanical integrity of the graft. Our aim in this study was to document the time-dependent mechanical properties of the morsellised graft. This information is useful in clinical application of the graft, in studies of migration of the implant and in the design of the joint. We used 16 specimens of impacted, morsellised cancellous bone from the sternum of goats to assess the mechanical properties by confined compression creep tests. Consideration of the graft material as a porous, permeable solid, filled with fluid, allowed determination of the compressive modulus of the matrix, and its permeability to fluid flow. In all specimens the compression tests showed large, irreversible deformations, caused by flow-independent creep behaviour as a result of rolling and sliding of the bone chips. The mean permeability was 8.82 *10−12 m4/Ns (SD 43%), and the compressive modulus was 38.7 MPa (SD 34%). No correlation was found between the apparent density and the permeability or between the apparent density and the compressive modulus. The irreversible deformations in the graft could be captured by a creep law, for which the parameters were quantified. We conclude that in clinical use the graft is bound to be subject to permanent deformation after operation. The permeability of the material is relatively high compared with, for example, human cartilage. The confined compression modulus is relatively low compared with cancellous bone of the same apparent density. Designs of prostheses used in revision surgery must accommodate the viscoelastic and permanent deformations in the graft without causing loosening at the interface.
We report a long-term review of 60 acetabular components revised using impacted, morsellised bone allografts and a cemented polyethylene cup. The acetabular defects were cavitary (37) or combined (23). Follow-up was for a mean 11.8 years (10 to 15). Further revision was needed in five hips, two for septic and three for aseptic loosening. The overall survival rate at 11.8 years was 90%; excluding the septic cases it was 94%. Acetabular reconstruction with impacted morsellised cancellous grafts and cement gives satisfactory long-term results.