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Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_14 | Pages 6 - 6
10 Oct 2023
Burt J Jabbal M Moran M Jenkins P Walmsley P Clarke J
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The aim of this study was to measure the effect of hospital case volume on the survival of revision total hip arthroplasty (RTHA). This is a retrospective analysis of Scottish Arthroplasty Project data, a nationwide audit which prospectively collects data on all arthroplasty procedures performed in Scotland. The primary outcome was RTHA survival at ten years. The primary explanatory variable was the effect of hospital case volume per year on RTHA survival. Kaplan-Meier survival curves were plotted with 95% confidence intervals (CIs) to determine the lifespan of RTHA. Multivariate Cox proportional hazards were used to estimate relative revision risks over time. Hazard ratios (HRs) were reported with 95% CI, and p-value < 0.05 was considered statistically significant. From 1999 to 2019, 13,020 patients underwent RTHA surgery in Scotland (median age at RTHA 70 years (interquartile range (IQR) 62 to 77)). In all, 5,721 (43.9%) were female, and 1065 (8.2%) were treated for infection. 714 (5.5%) underwent a second revision procedure. Co-morbidity, younger age at index revision, and positive infection status were associated with need for re-revision (p<0.001). The ten-year survival estimate for RTHA was 93.3% (95% CI 92.8 to 93.8). Adjusting for sex, age, surgeon volume, and indication for revision, high hospital case volume was not significantly associated with lower risk of re-revision (HR1, 95% CI 1.00 to 1.00, p 0.073)). The majority of RTHA in Scotland survive up to ten years. Increasing yearly hospital case volume cases is not independently associated with a significant risk reduction of re-revision


The Bone & Joint Journal
Vol. 102-B, Issue 10 | Pages 1384 - 1391
3 Oct 2020
Yoo S Jang EJ Jo J Jo JG Nam S Kim H Lee H Ryu HG

Aims. Hospital case volume is shown to be associated with postoperative outcomes in various types of surgery. However, conflicting results of volume-outcome relationship have been reported in hip fracture surgery. This retrospective cohort study aimed to evaluate the association between hospital case volume and postoperative outcomes in patients who had hip fracture surgery. We hypothesized that higher case volume would be associated with lower risk of in-hospital and one-year mortality after hip fracture surgery. Methods. Data for all patients who underwent surgery for hip fracture from January 2008 to December 2016 were extracted from the Korean National Healthcare Insurance Service database. According to mean annual case volume of surgery for hip fracture, hospitals were classified into very low (< 30 cases/year), low (30 to 50 cases/year), intermediate (50 to 100 cases/year), high (100 to 150 cases/year), or very high (> 150 cases/year) groups. The association between hospital case volume and in-hospital mortality or one-year mortality was assessed using the logistic regression model to adjust for age, sex, type of fracture, type of anaesthesia, transfusion, comorbidities, and year of surgery. Results. Between January 2008 and December 2016, 269,535 patients underwent hip fracture surgery in 1,567 hospitals in Korea. Compared to hospitals with very high volume, in-hospital mortality rates were significantly higher in those with high volume (odds ratio (OR) 1.10, 95% confidence interval ((CI) 1.02 to 1.17, p = 0.011), low volume (OR 1.22, 95% CI 1.14 to 1.32, p < 0.001), and very low volume (OR 1.25, 95% CI 1.16 to 1.34, p < 0.001). Similarly, hospitals with lower case volume showed higher one-year mortality rates compared to hospitals with very high case volume (low volume group, OR 1.15, 95% CI 1.11 to 1.19, p < 0.001; very low volume group, OR 1.10, 95% CI 1.07 to 1.14, p < 0.001). Conclusion. Higher hospital case volume of hip fracture surgery was associated with lower in-hospital mortality and one-year mortality in a dose-response fashion. Cite this article: Bone Joint J 2020;102-B(10):1384–1391


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVII | Pages 141 - 141
1 Sep 2012
Badawy M Espehaug B Indrekvam K Furnes O
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Background. Improving quality and efficiency is a priority in health policy. Several studies have shown a correlation between high hospital volume and improved results of surgery. In Norway, orthopaedic surgeons operate a relatively low number of total knee replacements compared with other countries. The number of total knee replacements has, however, increased significantly over the past 10 years. Some studies have also shown an association between surgeon volume and outcomes after total knee arthroplasty (TKA). Purpose. We wanted to study a possible correlation between prosthesis survival and surgery volume of TKA, both with respect to hospital volume and surgeon volume. Materials and Methods. To examine the annual surgery volume per hospital we used registry data from the Norwegian Arthroplasty Register (NAR) for cemented TKA without patella component from 1994–2009. A questionnaire regarding surgeon volume in 2000 and 2009 was sent to all 58 operating hospitals in Norway, as this is not registered in the NAR. We received responses from 29 hospitals. Surgeon volume was defined by the percentage of surgeons at the hospital who operated 1–10 TKA over a year. Cox regression (without adjustment) was used to estimate proportions without revision and relative differences (RR). Analyses were also done for a subset of commonly used prostheses (AGC, LCS, LCS Complete, Duracon, NexGen, Profix), and for the prosthesis LCS and Profix separately. Results. Median annual hospital volume increased from 19 knees in 1995 to 83 in 2009. Prosthesis survival at 10 years was 92.5% (95% CI: 91.6–93.4) with 1–24 operations annually and 95.3% (93.7–96.8) with 100–149 operations. We found a lower risk of revision for hospitals with 25–49 (RR = 0.86, p = 0.06), 50–99 (RR = 0.81, p = 0.01, 100–149 (RR = 0.59, p<0.001 and 150 or more (RR = 0.48, p <.001) operations per year, compared to the hospitals with 1–24 operations. The analyses for subgroups of prosthesis brands provided similar results, except for the Profix prosthesis where there was no difference between hospital volumes. In 2000, 47% of the Norwegian hospitals had two thirds of the surgeons operating 1–10 TKA annually, but this was reduced to 24% in 2009. High annual surgeon volume gave the best results in our analyses. Conclusion. There has been an increase in the number of TKAs over time, in Norway as in other countries. Surgeon volume has also increased over time. Previously a high number of surgeons performed a low number of total knee arthroplasties, but this has been significantly reduced over the last 10 years. Survival curves from the NAR show a gradual improvement over time regarding the results of TKA. Our study indicated better results for TKA both at higher hospital volume and surgeon volume. Further analyses should investigate whether other factors may have an influence on this result


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_16 | Pages 33 - 33
1 Apr 2013
Morse A McDonald MM Kramer I Kneissel M Kelly NH Melville KM van der Meulen MC
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Introduction. Canonical Wnt inhibitor Sclerostin (SOST) may be a key mechanotransduction regulator. Methods. Unloading/loading 10 week old Sost−/− and WT mice. Unloading: Quads and calf muscles injected each with 0.5U botulinum toxin (BTX, Allergan) caused tibial unloading. Loading: 1200 cycles of tibial axial loading, 1200μe on mid-shaft, 4Hz, 5 days/week. Treated and control tibiae μCT scanned (Skyscan 1174) at 2 weeks. Results. Unloading the WT tibiae significantly decreased cortical bone volume (−5%) and thickness (−7%) compared to WT control (p<0.01). Larger bone volume loss (−25%) was seen in the trabecular compartment (p<0.01), along with 10% and 22% decreases in trabecular thickness and number (p<0.01). These parameters were not altered between unloaded and control Sost−/− tibiae. Tibial loading increased cortical bone volume in WT (18%) and Sost−/− (25%) mice (p<0.01). Cortical thickness was also increased in WT (19%) and Sost−/− (17%) mice (p<0.01). The trabeculae of the WT loaded tibiae showed significant thickening (15%, p<0.01) not seen in the Sost−/− tibiae. Metaphyseal cortical bone volume increased in both loaded WT (13%) and Sost−/− (31%) tibiae compared to their controls (p<0.01), suggestive of metaphyseal corticalisation. Conclusion. SOST knockout inhibited unloading-induced bone loss, but not loading-induced bone gain. SOST may have an important role in bones response to unloading, but may not be essential for the response to loading


The Bone & Joint Journal
Vol. 105-B, Issue 2 | Pages 180 - 189
1 Feb 2023
Tohidi M Mann SM Groome PA

Aims. This study aimed to describe practice variation in the use of total hip arthroplasty (THA) for older patients with femoral neck fracture and to determine the association between patient, surgeon, and institution factors and treatment with THA. Methods. We performed a cross-sectional analysis of 49,597 patients aged 60 years and older from Ontario, Canada, who underwent hemiarthroplasty or THA for femoral neck fracture between 2002 and 2017. This population-based study used routinely collected healthcare databases linked through ICES (formerly known as the Institute for Clinical Evaluative Sciences). Multilevel logistic regression modelling was used to quantify the association between patient, surgeon, and institution-level variables and whether patients were treated with THA. Variance partition coefficient and median odds ratios were used to estimate the variation attributable to higher-level variables and the magnitude of effect of higher-level variables, respectively. Results. Over the study period, 9.4% of patients (n = 4,638) were treated with THA. Patient factors associated with higher likelihood of treatment by THA included: younger age, male sex, and diagnosis with rheumatoid arthritis. Long-term care residence, use of home care services prior to hip fracture, diagnosis of dementia, higher comorbidity burden, and the most marginalized group were negatively associated with treatment by THA. Treating surgeon and institution accounted for 54.2% and 17.8% of the total variation in treatment with THA, respectively. Surgeon volume of THA procedures in the 365 days prior to surgery was the strongest higher-level predictor of treatment with THA. Specific treating surgeons and institutions still accounted for significant proportions of the variability in treatment with THA (40.3% and 19.5% of total observed variation, respectively) after controlling for available patient, surgeon, and institution-level variables. Conclusion. The strongest predictors for treatment of patients with femoral neck fracture with THA were patient age, treating surgeon, and treating institution. This practice variation highlights differential access to care for patients. Cite this article: Bone Joint J 2023;105-B(2):180–189


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_6 | Pages 3 - 3
1 Jun 2022
Chuntamongkol R Burt J Zaffar H Habbick T Picard F Clarke J Gee C
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There is a longstanding presumed association between obesity, complications, and revision surgery in primary knee arthroplasty. This has more recently been called into question, particularly in centres where a high volume of arthroplasty is performed. We investigated the correlation between Body Mass Index (BMI), mortality, and revision surgery. This was a cohort study of at least 10 years following primary knee arthroplasty from a single high volume arthroplasty unit. Mortality and revision rates were collected from all patients who underwent primary knee arthroplasty between 2009 and 2010. Kaplan Meier analysis was performed. There were 1161 female and 948 male patients with a mean age of 69 (21 to 97). All cause survivorship excluding mortality was 97.2% up to 13yrs with a minimum of 10 years. The revision rate in this series was 2.8% with no significant difference in revision rates after 10 year between patients with BMI above and below 40 (p=0.438). There was no significant difference in 10–year mortality between patients above and below a BMI of 40 (p=0.238). This study shows no significant difference in the long term survival of total knee replacement between patients with normal and high BMI. Careful consideration should be given before rationing surgery based on BMI alone


The Bone & Joint Journal
Vol. 104-B, Issue 7 | Pages 884 - 893
1 Jul 2022
Kjærvik C Gjertsen J Stensland E Saltyte-Benth J Soereide O

Aims. This study aimed to identify risk factors (patient, healthcare system, and socioeconomic) for mortality after hip fractures and estimate their relative importance. Further, we aimed to elucidate mortality and survival patterns following fractures and the duration of excess mortality. Methods. Data on 37,394 hip fractures in the Norwegian Hip Fracture Register from January 2014 to December 2018 were linked to data from the Norwegian Patient Registry, Statistics Norway, and characteristics of acute care hospitals. Cox regression analysis was performed to estimate risk factors associated with mortality. The Wald statistic was used to estimate and illustrate relative importance of risk factors, which were categorized in modifiable (healthcare-related) and non-modifiable (patient-related and socioeconomic). We calculated standardized mortality ratios (SMRs) comparing deaths among hip fracture patients to expected deaths in a standardized reference population. Results. Mean age was 80.2 years (SD 11.4) and 67.5% (n = 25,251) were female. Patient factors (male sex, increasing comorbidity (American Society of Anesthesiologists grade and Charlson Comorbidity Index)), socioeconomic factors (low income, low education level, living in a healthcare facility), and healthcare factors (hip fracture volume, availability of orthogeriatric services) were associated with increased mortality. Non-modifiable risk factors were more strongly associated with mortality than modifiable risk factors. The SMR analysis suggested that cumulative excess mortality among hip fracture patients was 16% in the first year and 41% at six years. SMR was 2.48 for the six-year observation period, most pronounced in the first year, and fell from 10.92 in the first month to 3.53 after 12 months and 2.48 after six years. Substantial differences in median survival time were found, particularly for patient-related factors. Conclusion. Socioeconomic, patient-, and healthcare-related factors all contributed to excess mortality, and non-modifiable factors had stronger association than modifiable ones. Hip fractures contributed to substantial excess mortality. Apparently small survival differences translate into substantial disparity in median survival time in this elderly population. Cite this article: Bone Joint J 2022;104-B(7):884–893


The Bone & Joint Journal
Vol. 103-B, Issue 2 | Pages 264 - 270
1 Feb 2021
Nilsen SM Asheim A Carlsen F Anthun KS Johnsen LG Vatten LJ Bjørngaard JH

Aims. Few studies have investigated potential consequences of strained surgical resources. The aim of this cohort study was to assess whether a high proportion of concurrent acute surgical admissions, tying up hospital surgical capacity, may lead to delayed surgery and affect mortality for hip fracture patients. Methods. This study investigated time to surgery and 60-day post-admission death of patients 70 years and older admitted for acute hip fracture surgery in Norway between 2008 and 2016. The proportion of hospital capacity being occupied by newly admitted surgical patients was used as the exposure. Hip fracture patients admitted during periods of high proportion of recent admissions were compared with hip fracture patients admitted at the same hospital during the same month, on similar weekdays, and times of the day with fewer admissions. Results. Among 60,072 patients, mean age was 84.6 years (SD 6.8), 78% were females, and median time to surgery was 20 hours (IQR 11 to 29). Overall, 14% (8,464) were dead 60 days after admission. A high (75. th. percentile) proportion of recent surgical admission compared to a low (25. th. percentile) proportion resulted in 20% longer time to surgery (95% confidence interval (CI) 16 to 25) and 20% higher 60-day mortality (hazard ratio 1.2, 95% CI 1.1 to 1.4). Conclusion. A high volume of recently admitted acute surgical patients, indicating probable competition for surgical resources, was associated with delayed surgery and increased 60-day mortality. Cite this article: Bone Joint J 2021;103-B(2):264–270


The Bone & Joint Journal
Vol. 104-B, Issue 11 | Pages 1266 - 1272
1 Nov 2022
Farrow L Brasnic L Martin C Ward K Adam K Hall AJ Clement ND MacLullich AMJ

Aims

The aim of this study was to examine perioperative blood transfusion practice, and associations with clinical outcomes, in a national cohort of hip fracture patients.

Methods

A retrospective cohort study was undertaken using linked data from the Scottish Hip Fracture Audit and the Scottish National Blood Transfusion Service between May 2016 and December 2020. All patients aged ≥ 50 years admitted to a Scottish hospital with a hip fracture were included. Assessment of the factors independently associated with red blood cell transfusion (RBCT) during admission was performed, alongside determination of the association between RBCT and hip fracture outcomes.


The Bone & Joint Journal
Vol. 105-B, Issue 8 | Pages 872 - 879
1 Aug 2023
Ogawa T Onuma R Kristensen MT Yoshii T Fujiwara T Fushimi K Okawa A Jinno T

Aims

The aim of this study was to investigate the association between additional rehabilitation at the weekend, and in-hospital mortality and complications in patients with hip fracture who underwent surgery.

Methods

A retrospective cohort study was conducted in Japan using a nationwide multicentre database from April 2010 to March 2018, including 572,181 patients who had received hip fracture surgery. Propensity score matching was performed to compare patients who received additional weekend rehabilitation at the weekend in addition to rehabilitation on weekdays after the surgery (plus-weekends group), as well as those who did not receive additional rehabilitation at the weekend but did receive weekday rehabilitation (weekdays-only group). After the propensity score matching of 259,168 cases, in-hospital mortality as the primary outcome and systemic and surgical complications as the secondary outcomes were compared between the two groups.


The Bone & Joint Journal
Vol. 106-B, Issue 1 | Pages 62 - 68
1 Jan 2024
Harris E Clement N MacLullich A Farrow L

Aims

Current levels of hip fracture morbidity contribute greatly to the overall burden on health and social care services. Given the anticipated ageing of the population over the coming decade, there is potential for this burden to increase further, although the exact scale of impact has not been identified in contemporary literature. We therefore set out to predict the future incidence of hip fracture and help inform appropriate service provision to maintain an adequate standard of care.

Methods

Historical data from the Scottish Hip Fracture Audit (2017 to 2021) were used to identify monthly incidence rates. Established time series forecasting techniques (Exponential Smoothing and Autoregressive Integrated Moving Average) were then used to predict the annual number of hip fractures from 2022 to 2029, including adjustment for predicted changes in national population demographics. Predicted differences in service-level outcomes (length of stay and discharge destination) were analyzed, including the associated financial cost of any changes.


The Bone & Joint Journal
Vol. 106-B, Issue 9 | Pages 986 - 993
1 Sep 2024
Hatano M Sasabuchi Y Isogai T Ishikura H Tanaka T Tanaka S Yasunaga H

Aims

The aim of this study was to compare the early postoperative mortality and morbidity in older patients with a fracture of the femoral neck, between those who underwent total hip arthroplasty (THA) and those who underwent hemiarthroplasty.

Methods

This nationwide, retrospective cohort study used data from the Japanese Diagnosis Procedure Combination database. We included older patients (aged ≥ 60 years) who underwent THA or hemiarthroplasty after a femoral neck fracture, between July 2010 and March 2022. A total of 165,123 patients were included. The THA group was younger (mean age 72.6 (SD 8.0) vs 80.7 years (SD 8.1)) and had fewer comorbidities than the hemiarthroplasty group. Patients with dementia or malignancy were excluded because they seldom undergo THA. The primary outcome measures were mortality and complications while in hospital, and secondary outcomes were readmission and reoperation within one and two years after discharge, and the costs of hospitalization. We conducted an instrumental variable analysis (IVA) using differential distance as a variable.


The Bone & Joint Journal
Vol. 106-B, Issue 1 | Pages 77 - 85
1 Jan 2024
Foster AL Warren J Vallmuur K Jaiprakash A Crawford R Tetsworth K Schuetz MA

Aims

The aim of this study was to perform the first population-based description of the epidemiological and health economic burden of fracture-related infection (FRI).

Methods

This is a retrospective cohort study of operatively managed orthopaedic trauma patients from 1 January 2007 to 31 December 2016, performed in Queensland, Australia. Record linkage was used to develop a person-centric, population-based dataset incorporating routinely collected administrative, clinical, and health economic information. The FRI group consisted of patients with International Classification of Disease 10th Revision diagnosis codes for deep infection associated with an implanted device within two years following surgery, while all others were deemed not infected. Demographic and clinical variables, as well as healthcare utilization costs, were compared.


The Bone & Joint Journal
Vol. 100-B, Issue 9 | Pages 1234 - 1240
1 Sep 2018
Brady J Hardy BM Yoshino O Buxton A Quail A Balogh ZJ

Aims. Little is known about the effect of haemorrhagic shock and resuscitation on fracture healing. This study used a rabbit model with a femoral osteotomy and fixation to examine this relationship. Materials and Methods. A total of 18 male New Zealand white rabbits underwent femoral osteotomy with intramedullary fixation with ‘shock’ (n = 9) and control (n = 9) groups. Shock was induced in the study group by removal of 35% of the total blood volume 45 minutes before resuscitation with blood and crystalloid. Fracture healing was monitored for eight weeks using serum markers of healing and radiographs. Results. Four animals were excluded due to postoperative complications. The serum concentration of osteocalcin was significantly elevated in the shock group postoperatively (p < 0.0001). There were otherwise no differences with regard to serum markers of bone healing. The callus index was consistently increased in the shock group on anteroposterior (p = 0.0069) and lateral (p = 0.0165) radiographs from three weeks postoperatively. The control group showed an earlier decrease of callus index. Radiographic scores were significantly greater in the control group (p = 0.0025). Conclusion. In a rabbit femoral osteotomy model with intramedullary fixation, haemorrhagic shock and resuscitation produced larger callus but with evidence of delayed remodelling. Cite this article: Bone Joint J 2018;100-B:1234–40


Bone & Joint Open
Vol. 5, Issue 3 | Pages 218 - 226
15 Mar 2024
Voigt JD Potter BK Souza J Forsberg J Melton D Hsu JR Wilke B

Aims

Prior cost-effectiveness analyses on osseointegrated prosthesis for transfemoral unilateral amputees have analyzed outcomes in non-USA countries using generic quality of life instruments, which may not be appropriate when evaluating disease-specific quality of life. These prior analyses have also focused only on patients who had failed a socket-based prosthesis. The aim of the current study is to use a disease-specific quality of life instrument, which can more accurately reflect a patient’s quality of life with this condition in order to evaluate cost-effectiveness, examining both treatment-naïve and socket refractory patients.

Methods

Lifetime Markov models were developed evaluating active healthy middle-aged male amputees. Costs of the prostheses, associated complications, use/non-use, and annual costs of arthroplasty parts and service for both a socket and osseointegrated (OPRA) prosthesis were included. Effectiveness was evaluated using the questionnaire for persons with a transfemoral amputation (Q-TFA) until death. All costs and Q-TFA were discounted at 3% annually. Sensitivity analyses on those cost variables which affected a change in treatment (OPRA to socket, or socket to OPRA) were evaluated to determine threshold values. Incremental cost-effectiveness ratios (ICERs) were calculated.


The Bone & Joint Journal
Vol. 106-B, Issue 4 | Pages 387 - 393
1 Apr 2024
Dean BJF Riley N Little C Sheehan W Gidwani S Brewster M Dhiman P Costa ML

Aims

There is a lack of published evidence relating to the rate of nonunion seen in occult scaphoid fractures, diagnosed only after MRI. This study reports the rate of delayed union and nonunion in a cohort of patients with MRI-detected acute scaphoid fractures.

Methods

This multicentre cohort study at eight centres in the UK included all patients with an acute scaphoid fracture diagnosed on MRI having presented acutely following wrist trauma with normal radiographs. Data were gathered retrospectively for a minimum of 12 months at each centre. The primary outcome measures were the rate of acute surgery, delayed union, and nonunion.


The Bone & Joint Journal
Vol. 104-B, Issue 8 | Pages 997 - 1008
1 Aug 2022

Aims

The aim of this study was to describe the management and associated outcomes of patients sustaining a femoral hip periprosthetic fracture (PPF) in the UK population.

Methods

This was a multicentre retrospective cohort study including adult patients who presented to 27 NHS hospitals with 539 new PPFs between 1 January 2018 and 31 December 2018. Data collected included: management strategy (operative and nonoperative), length of stay, discharge destination, and details of post-treatment outcomes (reoperation, readmission, and 30-day and 12-month mortality). Descriptive analysis by fracture type was performed, and predictors of PPF management and outcomes were assessed using mixed-effects logistic regression.


The Bone & Joint Journal
Vol. 106-B, Issue 6 | Pages 613 - 622
1 Jun 2024
Shen J Wei Z Wu H Wang X Wang S Wang G Luo F Xie Z

Aims

The aim of the present study was to assess the outcomes of the induced membrane technique (IMT) for the management of infected segmental bone defects, and to analyze predictive factors associated with unfavourable outcomes.

Methods

Between May 2012 and December 2020, 203 patients with infected segmental bone defects treated with the IMT were enrolled. The digital medical records of these patients were retrospectively analyzed. Factors associated with unfavourable outcomes were identified through logistic regression analysis.


The Bone & Joint Journal
Vol. 104-B, Issue 11 | Pages 1256 - 1265
1 Nov 2022
Keene DJ Alsousou J Harrison P O’Connor HM Wagland S Dutton SJ Hulley P Lamb SE Willett K

Aims

To determine whether platelet-rich plasma (PRP) injection improves outcomes two years after acute Achilles tendon rupture.

Methods

A randomized multicentre two-arm parallel-group, participant- and assessor-blinded superiority trial was undertaken. Recruitment commenced on 28 July 2015 and two-year follow-up was completed in 21 October 2019. Participants were 230 adults aged 18 years and over, with acute Achilles tendon rupture managed with non-surgical treatment from 19 UK hospitals. Exclusions were insertion or musculotendinous junction injuries, major leg injury or deformity, diabetes, platelet or haematological disorder, medication with systemic corticosteroids, anticoagulation therapy treatment, and other contraindicating conditions. Participants were randomized via a central online system 1:1 to PRP or placebo injection. The main outcome measure was Achilles Tendon Rupture Score (ATRS) at two years via postal questionnaire. Other outcomes were pain, recovery goal attainment, and quality of life. Analysis was by intention-to-treat.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_12 | Pages 10 - 10
1 Jun 2016
Scott C Eaton M Nutton R Wade F Evans S Pankaj P
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25–40% of unicompartmental knee replacement (UKR) revisions are performed for unexplained pain possibly secondary to elevated proximal tibial bone strain. This study investigates the effect of tibial component metal backing and polyethylene thickness on cancellous bone strain in a finite element model (FEM) of a cemented fixed bearing medial UKR, validated using previously published acoustic emission data (AE). FEMs of composite tibiae implanted with an all-polyethylene tibial component (AP) and a metal backed one (MB) were created. Polyethylene of thickness 6–10mm in 2mm increments was loaded to a medial load of 2500N. The volume of cancellous bone exposed to <−3000 (pathological overloading) and <−7000 (failure limit) minimum principal (compressive) microstrain (µ∊) and >3000 and >7000 maximum principal (tensile) microstrain was measured. Linear regression analysis showed good correlation between measured AE hits and volume of cancellous bone elements with compressive strain <−3000µ∊: correlation coefficients (R= 0.947, R2 = 0.847), standard error of the estimate (12.6 AE hits) and percentage error (12.5%) (p<0.001). AP implants displayed greater cancellous bone strains than MB implants for all strain variables at all loads. Patterns of strain differed between implants: MB concentrations at the lateral edge; AP concentrations at the keel, peg and at the region of load application. AP implants had 2.2 (10mm) to 3.2 (6mm) times the volume of cancellous bone compressively strained <−7000µ∊ than the MB implants. Altering MB polyethylene insert thickness had no effect. We advocate using caution with all-polyethylene UKR implants especially in large or active patients where loads are higher