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Bone & Joint Open
Vol. 1, Issue 7 | Pages 398 - 404
15 Jul 2020
Roebke AJ Via GG Everhart JS Munsch MA Goyal KS Glassman AH Li M

Aims

Currently, there is no single, comprehensive national guideline for analgesic strategies for total joint replacement. We compared inpatient and outpatient opioid requirements following total hip arthroplasty (THA) versus total knee arthroplasty (TKA) in order to determine risk factors for increased inpatient and outpatient opioid requirements following total hip or knee arthroplasty.

Methods

Outcomes after 92 primary total knee (n = 49) and hip (n = 43) arthroplasties were analyzed. Patients with repeat surgery within 90 days were excluded. Opioid use was recorded while inpatient and 90 days postoperatively. Outcomes included total opioid use, refills, use beyond 90 days, and unplanned clinical encounters for uncontrolled pain. Multivariate modelling determined the effect of surgery, regional nerve block (RNB) or neuraxial anesthesia (NA), and non-opioid medications after adjusting for demographics, ength of stay, and baseline opioid use.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_2 | Pages 47 - 47
10 Feb 2023
Reason S Wainwright C
Full Access

Little guidance exists in the current literature regarding which patient recorded outcome measures (PROMs) are most clinically appropriate following anterior cruciate ligament reconstruction (ACL) surgery, and what results surgeons should expect or accept. Many PROMs have been validated, but their “ideal” results have not been published, limiting a surgeon's ability to compare their patients’ outcomes with those of their colleagues. We undertook a systematic review of PROMs for ACL to look at common usage and outcomes. After appropriate paper selection, we then undertook a pragmatic meta-analysis (i.e., including all papers that fulfilled the selection criteria, regardless of CONSORT status) and calculated weighted mean outcome scores and standard deviations for the most commonly used PROMs. A comprehensive literature search of all English articles of PubMed and other sources including search terms (‘Patient related outcome measure’ or ‘PROM’) AND ‘anterior cruciate ligament’ (limited to abstract/title) yielded 722 articles. Title review narrowed this to 268, and abstracts review to 151, of which 88 were included in our meta-analysis. Weighted mean and standard deviations were calculated for IKDC, KOOS, Lysholm, Teneger and “VAS Pain” PROMs as the most commonly reported. We identified significant, novel findings relating to selected PROMs and (i) demographics including age, gender and body mass index, (ii) surgical factors including bundle count, strand count, and graft type, and (iii) post operative complications. We clarified the most commonly used PROMs for ACL, and their weighted means and standard deviations. This will allow surgeons to compare results with colleagues, ensuring they meet international levels of quality in PROMs. We have also updated which patient and operative factors have an impact on PROMs scoring to allow for population variance


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_8 | Pages 31 - 31
10 May 2024
Clatworthy M Rahardja R Young S Love H
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Background. Anterior cruciate ligament (ACL) reconstruction with concomitant meniscal injury occurs frequently. Meniscal repair is associated with improved long-term outcomes compared to resection but is also associated with a higher reoperation rate. Knowledge of the risk factors for repair failure may be important in optimizing patient outcomes. Purpose. This study aimed to identify the patient and surgical risk factors for meniscal repair failure, defined as a subsequent meniscectomy, following concurrent primary ACL reconstruction. Methods. Data recorded by the New Zealand ACL Registry and the Accident Compensation Corporation, the New Zealand Government's sole funder of ACL reconstructions and any subsequent surgery, was reviewed. Meniscal repairs performed with concurrent primary ACL reconstruction was included. Root repairs were excluded. Univariate and multivariate survival analysis was performed to identify the patient and surgical risk factors for meniscal repair failure. Results. Between 2014 and 2020, a total of 3,024 meniscal repairs were performed during concurrent primary ACL reconstruction (medial repair = 1,814 and lateral repair = 1,210). The overall failure rate was 6.6% (n = 201) at a mean follow-up of 2.9 years, with a failure occurring in 7.8% of medial meniscal repairs (142 out of 1,814) and 4.9% of lateral meniscal repairs (59 out of 1,210). The risk of medial failure was higher in patients with a hamstring tendon autograft (adjusted HR = 2.20, p = 0.001), patients aged 21–30 years (adjusted HR = 1.60, p = 0.037) and in those with cartilage injury in the medial compartment (adjusted HR = 1.75, p = 0.002). The risk of lateral failure was higher in patients aged ≤ 20 years (adjusted HR = 2.79, p = 0.021) and when the procedure was performed by a surgeon with an annual ACL reconstruction case volume of less than 30 (adjusted HR = 1.84, p = 0.026). Conclusion. When performing meniscal repair during a primary ACL reconstruction, the use of a hamstring tendon autograft, younger age and the presence of concomitant cartilage injury in the medial compartment increases the risk of medial meniscal repair failure, whereas younger age and low surgeon volume increases the risk of lateral meniscal repair failure


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_12 | Pages 53 - 53
1 Dec 2022
Sidhu A Kerr J Howard L Masri B McEwen J Neufeld M
Full Access

Tourniquet use in total knee arthroplasty (TKA) remains a subject of considerable debate. A recent study questioned the need for tourniquets based on associated risks. However, the study omitted analysis of crucial tourniquet-related parameters which have been demonstrated in numerous studies to be associated with safe tourniquet use and reduction of adverse events. The current utilization and preferences of tourniquet use in Canada remain unknown. Our primary aim was to determine the current practices, patterns of use, and opinions of tourniquet use in TKA among members of the Canadian Arthroplasty Society (CAS). Additionally, we sought to determine the need for updated best practice guidelines to inform optimal tourniquet use and to identify areas requiring further research. A self-administered survey was emailed to members of the CAS in October 2021(six-week period). The response rate was 57% (91/161). Skip logic branching was used to administer a maximum of 59 questions related to tourniquet use, beliefs, and practices. All respondents were staff surgeons and 88% were arthroplasty fellowship trained. Sixty-five percent have been in practice for ≥11 years and only 16% for 50 TKA/year, 59% have an academic practice, and >67% prefer cemented TKA. Sixty-six percent currently use tourniquets, 25% no longer do but previously did, and 9% never used tourniquets. For those not using tourniquets, the most common reasons are potential harm/risks and publications/conferences. Among current users, 48% use in all cases and an additional 37% use in 76-99% of cases. The top reason for use was improved visualization/bloodless field (88%), followed by performing a cemented TKA, used in training, and faster operative times. The main patient factor influencing selective tourniquet use was peripheral vascular disease and main surgical factors were operative duration and cementless TKA. The most frequent adverse events reported were bruising/pinching under the tourniquet and short-term pain, which majority believed were related to improper tourniquet use (prolonged time, high-pressures, poor cuff fit), yet only 8% use contoured tourniquets and 32% don't use limb protection. Despite substantial evidence in literature that tourniquet safety and probability of harm are affected by tourniquet time and pressure, only 83% and 72% of respondents believe reducing tourniquet time and pressure respectively reduce the probability of harm. In addition, no surgeon utilizes personalized limb occlusion pressure which has been demonstrated to substantially reduce tourniquet pressure while being safe and effective. Furthermore, 62% always use fixed pressure and 37% will modify the pressure based on patient parameters, most often systolic blood pressure and limb size. Almost all (88%) were interested in new evidence-based guidelines regarding these parameters. Tourniquet use in TKA remains prevalent among arthroplasty surgeons in the CAS; however tremendous practice variability regarding several key parameters required for optimal use exists. Current best practices of tourniquet use regarding personalized pressures, time, and type are not being utilized across Canada. There is considerable interest and need for further research and updated guidelines regarding key parameters of safe tourniquet usage to optimize tourniquet use in TKA


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_3 | Pages 109 - 109
23 Feb 2023
Naufal E Shadbolt C Elsiwy Y Thuraisingam S Lorenzo Y Darby J Babazadeh S Choong P Dowsey M Stevens J
Full Access

This study aimed to evaluate the month-to-month prevalence of antibiotic dispensation in the 12 months before and after total knee arthroplasty (TKA) and total hip arthroplasty (THA) and to identify factors associated with antibiotic dispensation in the month immediately following the surgical procedure. In total, 4,115 THAs and TKAs performed between April 2013 and June 2019 from a state-wide arthroplasty referral centre were analysed. A cross-sectional study used data from an institutional arthroplasty registry, which was linked probabilistically to administrative dispensing data from the Australian Pharmaceutical Benefits Scheme. Multivariable logistic regression was carried out to identify patient and surgical risk factors for oral antibiotic dispensation. Oral antibiotics were dispensed in 18.3% of patients following primary TKA and 12.0% of patients following THA in the 30 days following discharge. During the year after discharge, 66.7% of TKA patients and 58.2% of THA patients were dispensed an antibiotic at some point. Patients with poor preoperative health status were more likely to have antibiotics dispensed in the month following THA or TKA. Older age, undergoing TKA rather than THA, obesity, inflammatory arthritis, and experiencing an in-hospital wound-related or other infectious complications were associated with increased antibiotic dispensation in the 30 days following discharge. A high rate of antibiotic dispensation in the 30 days following THA and TKA has been observed. Although resource constraints may limit routine wound review for all patients by a surgeon, a select cohort may benefit from timely specialist review postoperatively. Several risk factors identified in this study may aid in identifying appropriate candidates for such changes to follow-up care


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_3 | Pages 60 - 60
23 Feb 2023
Rahardja R Love H Clatworthy M Young S
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Meniscal repairs are commonly performed during anterior cruciate ligament (ACL) reconstruction. This study aimed to identify the risk factors for meniscal repair failure following concurrent primary ACL reconstruction. Primary ACL reconstructions with a concurrent repair of a meniscal tear recorded in the New Zealand ACL Registry between April 2014 and December 2018 were analyzed. Meniscal repair failure was defined as a patient who underwent subsequent meniscectomy, and was identified after cross-referencing data from the ACL Registry with the national database of the Accident Compensation Corporation (ACC). Multivariate Cox regression was performed to produce hazard ratios (HR) with 95% confidence intervals (CI) to identify the patient and surgical risk factors for meniscal repair failure. 2041 meniscal repairs were analyzed (medial = 1235 and lateral = 806). The overall failure rate was 9.4% (n = 192). Failure occurred in 11.1% of medial (137/1235) and 6.8% of lateral (55/806) meniscal repairs. The risk of medial failure was higher with hamstring tendon autografts (adjusted HR = 2.00, 95% CI 1.23 – 3.26, p = 0.006) and in patients with cartilage injury in the medial compartment (adjusted HR = 1.56, 95% CI 1.09 – 2.23, p = 0.015). The risk of lateral failure was higher when the procedure was performed by a surgeon with an annual case volume of less than 30 ACL reconstructions (adjusted HR = 1.92, 95% CI 1.10 – 3.33, p = 0.021). Age, gender, time from injury-to-surgery and femoral tunnel drilling technique did not influence the risk of meniscal repair failure. When repairing a meniscal tear during ACL reconstruction, the use of a hamstring tendon autograft or the presence of cartilage injury in the medial compartment increases the risk of medial meniscal repair failure. Lower surgeon case volume increases the risk of lateral meniscal repair failure


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_3 | Pages 59 - 59
23 Feb 2023
Rahardja R Mehmood A Coleman B Munro J Young S
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The optimal timing of when to perform manipulation under anesthesia (MUA) for stiffness following total knee arthroplasty (TKA) is unclear. This study aimed to identify the risk factors for MUA following primary TKA and whether performing an “early” MUA within 3 months results in a greater improvement in range of motion. Primary TKAs performed between January 2013 and December 2018 at three tertiary New Zealand hospitals were reviewed. International Classification of Diseases discharge coding was used to identify patients who underwent an MUA. Multivariate Cox regression was performed to identify patient and surgical risk factors for MUA. Pre- and post-MUA knee flexion angles were identified through manual review of operation notes. Multivariate linear regression was performed to compare the mean flexion angles pre- and post-MUA, as well as the mean gain in flexion, between patients undergoing “early” (<3 months) versus “late” MUA (>3 months). 7386 primary TKAs were analyzed in which 131 underwent subsequent MUA (1.8%). Patients aged <65 years were two times more likely to undergo MUA compared to patients aged ≥65 years (2.5% versus 1.3%, adjusted hazard ratio = 2.1, p<0.001). Gender, body mass index, patient comorbidities or a history of cancer were not associated with the risk of MUA. There was no difference in the final post-MUA flexion angle between patients who underwent early versus late MUA (104.7 versus 104.1 degrees, p = 0.819). However, patients who underwent early MUA had poorer pre-MUA flexion (72.3 versus 79.6 degrees, p = 0.012), and subsequently had a greater overall gain in flexion compared to patients who underwent late MUA (mean gain 33.1 versus 24.3 degrees, p<0.001). Younger age was the only patient risk factor for MUA. A greater overall gain in flexion was achieved in patients who underwent early MUA within 3 months


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_3 | Pages 56 - 56
23 Feb 2023
Rahardja R Love H Clatworthy M Young S
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Arthrofibrosis is a less common complication following anterior cruciate ligament (ACL) reconstruction and there are concerns that undergoing early surgery may be associated with arthrofibrosis. The aim of this study was to identify the patient and surgical risk factors for arthrofibrosis following primary ACL reconstruction. Primary ACL reconstructions prospectively recorded in the New Zealand ACL Registry between April 2014 and December 2019 were analyzed. The Accident Compensation Corporation (ACC) database was used to identify patients who underwent a subsequent reoperation with review of operation notes to identify those who had a reoperation for “arthrofibrosis” or “stiffness”. Univariate Chi-Square test and multivariate Cox regression analysis was performed. Hazard ratios (HR) with 95% confidence intervals (CI) were computed to identify the risk factors for arthrofibrosis. 9617 primary ACL reconstructions were analyzed, of which 215 patients underwent a subsequent reoperation for arthrofibrosis (2.2%). A higher risk of arthrofibrosis was observed in female patients (adjusted HR = 1.67, 95% CI 1.22 – 2.27, p = 0.001), patients with a history of previous knee surgery (adjusted HR = 1.97, 95% CI 1.11 – 3.50, p = 0.021) and when a transtibial femoral tunnel drilling technique was used (adjusted HR = 1.55, 95% CI 1.06 – 2.28, p = 0.024). Patients who underwent early ACL reconstruction within 6 weeks of their injury did not have a higher risk of arthrofibrosis when compared to patients who underwent surgery more than 6 weeks after their injury (3.5% versus 2.1%, adjusted HR = 1.56, 95% CI 0.97 – 2.50, p = 0.07). Age, graft type and concomitant meniscal injury did not influence the rate of arthrofibrosis. Female sex, a history of previous knee surgery and a transtibial femoral tunnel drilling technique are risk factors for arthrofibrosis following primary ACL reconstruction


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_12 | Pages 62 - 62
1 Dec 2022
Bansal R Bourget-Murray J Brunet L Railton P Sharma R Soroceanu A Piroozfar S Smith C Powell J
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The aim of this study was to determine the incidence, annual trend, perioperative outcomes, and identify risk factors of early-onset (≤ 90 days) deep surgical site infection (SSI) following primary total knee arthroplasty (TKA) for osteoarthritis. Risk factors for early-onset deep SSI were assessed. We performed a retrospective population-based cohort study using prospectively collected patient-level data from several provincial administrative data repositories between January 2013, and March 2020. The diagnosis of early-onset deep SSI was based on published Centre for Disease Control/National Healthcare Safety Network (CDC/NHSN) definitions. The Mann-Kendall Trend Test was used to detect monotonic trends in early-onset deep SSI rates over time. The effects of various patient and surgical risk factors for early-onset deep SSI were analyzed using multiple logistic regression. Secondary outcomes were 90-day mortality and 90-day readmission. A total of 20,580 patients underwent primary TKA for osteoarthritis. Forty patients had a confirmed deep SSI within 90-days of surgery representing a cumulative incidence of 0.19%. The annual infection rate did not change over the 7-year study period (p = 0.879). Risk factors associated with early-onset deep SSI included blood transfusions (OR, 3.93 [95% CI 1.34-9.20]; p=0.004), drug or alcohol abuse (OR, 4.91 [95% CI 1.85-10.93]; p<0.001), and surgeon volume less than 30 TKA per year (OR, 4.45 [1.07-12.43]; p=0.013). Early-onset deep SSI was not associated with 90-days mortality (OR, 11.68 [0.09-90-58]; p=0.217), but was associated with an increased chance of 90-day readmission (OR, 50.78 [26.47-102.02]; p<0.001). This study establishes a reliable baseline infection rate for early-onset deep SSI after TKA for osteoarthritis through the use of a robust methodological process. Several risk factors for early-onset deep SSI are potentially modifiable or can be optimized prior to surgery and be effective in reducing the incidence of early-onset SSI. This could guide the formulation of provincial screening programs and identify patients at high risk for SSI


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_12 | Pages 40 - 40
1 Dec 2022
Schmidt-Braekling T Thavorn K Poitras S Gofton W Kim P Beaulé P Grammatopoulos G
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With an ageing population and an increasing number of primary arthroplasties performed, the revision burden is predicted to increase. The aims of this study were to 1. Determine the revision burden in an academic hospital over a 11-year period; 2. identify the direct hospital cost associated with the delivery of revision service and 3. ascertain factors associated with increased cost. This is an IRB-approved, retrospective, single tertiary referral center, consecutive case series. Using the hospital data warehouse, all patients that underwent revision hip or knee arthroplasty surgery between 2008-2018 were identified. 1632 revisions were identified (1304 patients), consisting of 1061 hip and 571 knee revisions. The majority of revisions were performed for mechanical-related problems and aseptic loosening (n=903; 55.3%); followed by periprosthetic joint infection (n=553; 33.9%) and periprosthetic fractures (176; 10.8%). Cost and length of stay was determined for all patient. The direct in-hospital costs were converted to 2020 inflation-adjusted Canadian dollars. Several patients- (age; gender; HOMR- and ASA-scores; Hemoglobin level) and surgical- (indication for surgery; surgical site) factors were tested for possible associations. The number of revisions increased by 210% in the study period (2008 vs. 2018: 83 vs. 174). Revision indications changed over study period; with prevalence of fracture increasing by 460% (5 in 2008 vs. 23 in 2018) with an accompanying reduction in mechanical-related reasons, whilst revisions for infection remained constant. The mean annual cost over the entire study period was 3.9 MMCAD (range:2.4–5.1 MMCAD). The cost raised 150% over the study period from 2.4 MMCAD in 2008 to 3.6 MMCAD. Revisions for fractured had the greatest length of stay, the highest mean age, HOMR-score, ASA and cost associated with treatment compared to other revision indications (p < 0 .001). Patient factors associated with cost and length of stay included ASA- and HOMR-scores, Charlson-Comorbidity score and age. The revision burden increased 1.5-fold over the years and so has the direct cost of care delivery. The increased cost is primarily related to the prolonged hospital stay and increased surgical cost. For tertiary care units, these findings indicate a need to identify strategies on improving efficiencies whilst improving the quality of patient care (e.g. efficient ways of reducing acute hospital stay) and reducing the raise of the economic burden on a publicly funded health system


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_7 | Pages 98 - 98
1 Jul 2020
Bozzo A Adili A Madden K
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Total hip arthroplasty (THA) is one of the most successful and effective treatments for advanced hip osteoarthritis (OA). Over the last 5 years, Canada has seen a 17.8% increase in the number of hip replacements performed annually, and that number is expected to grow along with the aging Canadian population. However, the rise in THA surgery is associated with an increased number of patients at risk for the development of an infection involving the joint prosthesis and adjacent deep tissue – periprosthetic joint infections (PJI). Despite improved hygiene protocols and novel surgical strategies, PJI remains a serious complication. No previous population-based studies has investigated PJI risk factors using a time-to-event approach and none have focused exclusively on patients undergoing THA for primary hip OA. The purpose of this study is to determine risk factors for PJI after primary THA for OA using a large population-based database collected over 15 years. Our secondary objective is to determine the incidence of PJI, the time to PJI following primary THA, and if PJI rates have changed in the past 15 years. We performed a population-based cohort study using linked administrative databases in Ontario, Canada in accordance with RECORD and STROBE guidelines. All primary total hip replacements performed for osteoarthritis in patients aged 55 or older between January 1st 2002 – December 31st 2016 in Ontario, Canada were identified. Periprosthetic joint infection as the cause for revision surgery was identified with the International Classification of Diseases, 10th Edition (ICD-10), Clinical Modification diagnosis code T84.53 in any component of the healthcare data set. Data were obtained from the Institute for Clinical Evaluative Sciences (ICES). Demographic data and outcomes are summarized using descriptive statistics. We used a Cox proportional hazards model to analyze the effect of surgical factors and patient factors on the risk of developing PJI. Surgical factors include the approach, use of bone graft, use of cement, and the year of surgery. Patient factors include sex, age at surgery, income quintile and rurality (community vs. urban). We compared the 1,2,5 and 10 year PJI rates for patients undergoing THA each year of our cohort with the Cochran-Armitage test. Less than 0.1% of data were missing from all fields except for rurality which was lacking 0.3% of data. A total of 100,674 patients aged 55 or older received a primary total hip arthroplasty for osteoarthritis from 2002–2016. We identified 1034 cases of revision surgery for prosthetic joint infection for an overall PJI rate of 1.03%. When accounting for patients censored at final follow-up, the cumulative incidence for PJI is 1.44%. Our Cox proportional hazards model revealed that male sex, Type II diabetes mellitus, discharge to convalescent care, and having both hips replaced during one's lifetime were associated with increased risk of developing PJI following primary THA. Importantly, the time adjusted risk for PJI was equal for patients operated within the past 5 years, 6–10 years ago, or 11–15 years ago. The surgical approach, use of bone grafting or cement were not associated with increased risk of infection. PJI rates have not changed significantly over the past 15 years. One, two, five and ten-year PJI rates were similar for patients undergoing THA in all qualifying years. Analysis of a population-based cohort of 100,674 patients has shown that the risk of developing PJI following primary THA has not changed over 15 years. The surgical approach, use of bone grafting or cement were not associated with increased risk of infection. Male sex, Type II diabetes Mellitus and discharge to a rehab facility are associated with increased risk of PJI. As the risk of PJI has not changed in 15 years, an appropriately powered trial is warranted to determine interventions that can improve infection rate after THA


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_6 | Pages 48 - 48
1 May 2021
Togher C Shivji F Trompeter A
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Introduction. Non-union is agonising for patients, complex for surgeons and a costly burden to our healthcare service; as such, its management must be well defined. There is debate as to the requirements for the successful treatment of such patients, in particular, the need for additional biological therapies to ensure union. This study's primary aim was to determine if operative treatment alone was an effective treatment for the non-union of long bones in the upper and lower limbs compared to the pre-existing literature using biological therapies. Materials and Methods. A single-centre retrospective cohort study using prospectively collected data was performed. Inclusion was defined as patients 16 years or older with a radiologically confirmed non-union of the upper or lower limb long bones managed with surgical treatment alone between 2014–2019, with at least a 12 month follow up. Patients with bone defects or whose non-unions were treated with biological therapies were excluded from this study. The primary aim was assessed via the outcomes of union, time to union and RUST score. Results. 82 patients were included, 43 receiving percutaneous interventions and 39 receiving open interventions. Overall, a union rate of 97.56% was achieved with a mean time to union of 6.43 months. The mean RUST score increased from 6.09 at diagnosis to a final RUST score of 11.36 (p < 0.0001). Surgical factors showed that percutaneous interventions were most successful with a union rate of 100.00% with a mean time to union of 6.29 months. Augmentation surgery was associated with the shortest time to union of 4.47 months. Binary regression showed no statistically significant influence of patient factors. In 16 patients, complications were observed, including limb length discrepancy, ongoing pain and subsequent ankle problems. Conclusions. These results show non-inferior outcomes using operative treatment alone in non-union management as compared to the pre-existing literature on using biological therapies. Percutaneous interventions showed the most successful results and patient factors seemed to have little influence on this method's success. The continued use of biological therapies as a first line treatment should be questioned


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_1 | Pages 13 - 13
1 Feb 2021
Gardner C Karbanee N Wang L Traynor A Cracaoanu I Thompson J Hardaker C
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Introduction. Total Hip Arthroplasty (THA) devices are now increasingly subjected to a progressively greater range of kinematic and loading regimes from substantially younger and more active patients. In the interest of ensuring adequate THA solutions for all patient groups, THA polyethylene acetabular liner (PE Liner) wear representative of younger, heavier, and more active patients (referred to as HA in this study) warrants further understanding. Previous studies have investigated HA joint related morbidity [1]. Current or past rugby players are more likely to report osteoarthritis, osteoporosis, and joint replacement than a general population. This investigation aimed to provide a preliminary understanding of HA patient specific PE liner tribological performance during Standard Walking (SW) gait in comparison to IS0:14242-1:2014 standardized testing. Materials and Methods. Nine healthy male subjects volunteered for a gait lab-based study to collect kinematics and loading profiles. Owing to limitations in subject selection, five subjects wore a weighted jacket to increase Body Mass Index ≥30 (BMI). An induced increase in Bodyweight was capped (<30%BW) to avoid significantly effecting gait [3] (mean=11%BW). Six subjects identified as HA per BMI≥30, but with anthropometric ratios indicative of lower body fat as previously detailed by the author [2] (Waist-to-hip circumference ratio and waist circumference-to-height ratio). Three subjects identified as Normal (BMI<25). Instrumented force plate loading profiles were scaled (≈270%BW) in agreement with instrumented hip force data [4]. A previously verified THA (Pinnacle® Marathon® 36×56mm, DePuy Synthes) Finite Element Analysis wear model based on Archard's law and modified time hardening model [5] was used to predict geometrical changes due to wear and deformation, respectively (Figure 1). Subject dependent kinematic and loading conditions were sampled to generate, for both legs, 19 SW simulation runs using a central composite design of response surface method. Results. HA group demonstrated comparable SW gait characteristics and Range of Motion (RoM) to the Normal group (p>0.1) (Figure 2) but statistically greater SW peak loads, PE liner wear rates, deformation, and penetration after 3Mc (Million cycles) of SW (p<0.01). HA group demonstrated comparable RoM (p>0.4) and peak loading to ISO-14242-1:2014 (p>0.1) although, up to 8° increase in flexion-extension angle was observed. The HA group demonstrated statistically greater wear rates (mean 7.5% increase) to ISO-14242-1:2014 (p<0.05) (Figure 3). No difference in PE liner deformation or penetration was observed (p>0.4). Discussion. This study detailed only a 19. th. percentile within a broader HA population (BW=91kg, n=485) [6] however, were statistically worst-case compared to a Normal group and ISO-14242-1:2014. A 95. th. percentile HA population (BW=127kg) may produce lower PE liner tribological performance than reported in this investigation and therefore, warrants further investigation. Further studies would be beneficial to determine whether the increase in PE liner wear rate for HA patients is predictable based on kinematics and loading alone, or whether influences exist in design inputs and surgical factors. Conclusion. The HA population detailed in this study (representative of a 19. th. percentile) demonstrated statistically greater SW PE liner wear rates compared to ISO-14242-1:2014. This study may have implications for the test methods considered appropriate to verify novel designs. For any figures or tables, please contact the authors directly


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_8 | Pages 27 - 27
1 May 2016
Harato K Niki Y Sakurai A Uno N Morishige Y Nagura T
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Introduction. Wound condition after primary total knee arthroplasty (TKA) is important for prevention of periprosthetic infection. Any delay in wound healing will cause deep infection, which leads to the arthroplasty failure. Prevention of soft tissue problems is thus essential to achieve excellent clinical results. However, it is unknown as to the important surgical factors affecting the wound healing using detailed wound score after primary TKA so far. It was hypothesized that operative technique would affect wound healing in primary TKA. The purpose of the present study was to investigate and to clarify the important surgical factors affecting wound score after primary TKA. Methods. A total of 139 knees in 128 patients (mean 73 years) were enrolled. All primary TKAs were done by single surgeon. All patients underwent unilateral or bilateral TKA using Balanced Knee System®, posterior stabilized (PS) design (Ortho Development, Draper, UT) or Legion®, PS design (Smith and Nephew, Memphis, TN) under general and/or epidural anesthesia. Patients with immunosuppressive therapy, hypokalemia, poor nutrition (albumin < 3.4 g/dL), diverticulosis, infection elsewhere, uncontrolled diabetes mellitus (HbA1C>7.0%), obesity (Body Mass Index > 35 kg/m2), smoking, renal failure, hypothyroidism, alcohol abuse, rheumatoid arthritis, posttraumatic arthritis, and previous knee surgery were excluded. Hollander Wound Evaluation Score (HWES) was assessed on postoperative day 14. We evaluated age, sex, body mass index, HbA1C (%), preoperative femorotibial angle (FTA) on plain radiograph. In addition, intraoperative patella eversion, intraoperative anterior translation of the tibia, patella resurfacing, surgical time, tourniquet time, unidirectional barbed suture and length of skin incision were also evaluated as surgical factors. Multiple regression analysis was done using stepwise method to identify the surgical factors affecting HWES. Results. Detailed demographic data was presented in Table 1. The average HWES was 5.0 ± 0.8 point. As to the distribution of the HWES, data was shown in Figure 1. Namely, HWES was 3 point in 5 cases, 4 in 29 cases, 5 in 63 cases, and 6 in 42 cases. As any adverse events were not found in each TKA, there were no cases requiring debridement and re-closure of the wound after primary TKA. According to stepwise forward regression test, intraoperative patella eversion and anterior translation of the tibia were entered in this model, while age, Sex, BMI, HbA1C, FTA, surgical time, tourniquet time, patella resurfacing, unidirectional barbed suture and length of skin incision were not entered in the model. The multiple regression analysis in the current study would show the appropriate results, as Durbin-Watson ratio was 1.762. Standardized partial regression coefficient was as follows; 0.57 in anterior translation of the tibia, 0.38 in patella eversion (Table 2). Discussion. The results of the present study would support out hypothesis that operative technique would affect wound healing in primary TKA. Specifically, intraoperative patella eversion and anterior translation of the tibia should be avoided for quality cosmesis of the wound healing in primary TKA. To view tables/figures, please contact authors directly


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_6 | Pages 12 - 12
1 Jul 2020
Axelrod D Wasserstein D Zochowski T Marks PH Mahomed N Veljkovic A
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The purpose of this study was to define the risk and incidence of eventual ankle arthroplasty or fusion after documented ankle fracture in a large cohort, and compare that rate to matched healthy patients from the general population. The Ontario health insurance plan (OHIP) physician billing database, Institute for Clinical Evaluative Sciences (ICES) Physician Database, the Canadian Institute for Health Information (CIHI) databases, Discharge Abstract Database (DAD) and Same Day Surgery (SDS) were used to identify patients treated surgically and non-surgically for ankle fractures. Each patient was matched to four individuals from the general population (13.5 million) with no documented prior treatment for ankle fracture, according to age, sex, income, and urban/rural residence. Fusion and replacement incidence was compared using time-to-event analysis (Kaplan-Meier). A Cox Proportional Hazards model was used to explore the influence of patient, provider and surgical factors on time to surgery. We identified 45,444 (58.8% female, mean age 48.7 years) and 140, 629 (53.9% female, mean age 47.1 years) patients who had undergone open reduction internal fixation (ORIF) or non-operative management of an ankle fracture (NOA), respectively. Among ORIF patients, n=237 (0.5%) and n=69 (0.15%) patients underwent fusion or arthroplasty after a median 2.8 and 6.9 years, respectively. Among non-operatively treated ankle fractures, n=198 (0.14%) and n=36 (0.03%) patients underwent fusion or arthroplasty after a median of 3.2 and 5.6 years, respectively. Surgical treatment (vs. non-operatively treated fracture), older age, greater co-morbidity and a history of infection post fracture significantly increased the risk of eventual fusion or arthroplasty (HR 3.6 (3.1–4.3), p < 0 .001, HR 1.01 (1.01–1.02), p=0.009, HR 1.2 (1.1–1.3), p < 0 .001, HR 11.3 (6.8–18.7), p < 0 .001, respectively). Compared to matched controls, the risk of fusion/arthroplasty was not independent of time, following an exponential decay pattern. ORIF patient risk was 20 times greater than the general population in the first three years post-ORIF, and approached the risk of non-operatively treated patients (HR 4.5 (95CI: 3.5–5.8), p < 0 .0001) by approximately 14 years out from injury on time and comorbidity adjusted KM curves. Rates of fusion/arthroplasty are very low after ORIF and non-operative treatment of an ankle fracture in the general population of a public healthcare system. Utilization patterns suggest fusion is more common earlier, and arthroplasty remote, which may be a factor of patient age, injury severity, and complications from initial injury/surgery. Patients who underwent ORIF have >20 times the risk of fusion/arthroplasty in the short-term, however, the risk decreases over time eventually approaching that of non-operatively treated patients (∼4.5x the general population) when compared to non-fractured controls


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_5 | Pages 87 - 87
1 Mar 2017
Plate J Wohler A Brown M Fino N Langfitt M Lang J
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Introduction. Arthrofibrosis following total knee arthroplasty (TKA) is a complex and multifactorial complication that may require manipulation under anesthesia (MUA). However, patient and surgical factors that potentially influence the development of knee stiffness following TKA are not fully understood. The purpose of this study was to identify patient and surgical factors that may influence arthrofibrosis following TKA by assessing a cohort of patient that underwent MUA and comparing them to a matched cohort of patients without arthrofibrosis. Methods. The joints registry of a university hospital was searched for patient that underwent MUA following primary TKA between 2004 and 2013. Demographic and surgical information was obtained from the electronic medical record including range of motion (ROM), comorbidities and timing of MUA. Patients who underwent MUA were then double-matched by baseline (prior to primary TKA) knee ROM to patients who underwent primary TKA without postoperative arthrofibrosis during the same time period. Results. Fifty-two patients (56 TKAs, 71% female, mean BMI 32.2kg/m2) underwent MUA after TKA during the study period. MUA was performed a mean of 13.6 weeks after primary TKA. Study patient were then double-matched by baseline flexion (mean 107º±2º) to 111 patients (112 TKAs) with a similar mean baseline flexion (104º±2º, p=0.138). Patient requiring MUA were younger (mean age 56 vs. 64 years, p<0.001), had more comorbidities (5 vs. 3, p<0.001), and a higher number of previous knee surgery (56% vs. 21%, p<0.001) compared with controls. The risk for requiring MUA following primary TKA was significantly higher (2.4, p<0.001) in patient with previous knee surgery (arthroscopy for meniscal pathology, ACL reconstruction, osteotomies). Tourniquet time, length of stay, number of physical therapy sessions, blood loss >50 mL and any complication during the hospital stay were not found to be associated with increased risk of requiring MUA. Discussion. Younger patients with more comorbidities and a history of previous knee surgery were found to have significantly higher risk for developing arthrofibrosis and requiring MUA after primary TKA in the current study. Patients with this risk profile need to counseled regarding the risk for arthrofibrosis possibly requiring MUA after primary TKA


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_5 | Pages 93 - 93
1 Mar 2017
Pourzal R Cip J Rad E Laurent M Jacobs J Wimmer M
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Introduction. Wear debris from polyethylene tibial inserts has been associated with limited longevity of total knee replacements (TKRs). While material factors were studied extensively and considerable progress has been made, there is little knowledge about surgical factors, particularly on how the wear rate is related to implant positioning. It was the purpose of this study to determine the combined effect of patient and implant positioning factors on the volumetric wear rate of TKRs. Our hypothesis was that implant alignment has a significant impact on the wear rate when controlled for other patient factors. Methods. This study included 59 tibial inserts of a cruciate retaining TKR design (Nexgen, Zimmer Inc.). The patients' age, sex, weight, height, and implant size were obtained. All implants were scanned with a coordinate measuring machine. Volumetric wear was determined using an autonomous mathematical reconstruction method (Figure 1). Radiographs were used to determine the anatomic lateral distal femoral angle (aLDFA), anatomic medial proximal tibial angle (aMPTA), femoral tilt angle (FTA) and posterior tibial slope (PTS). Also, the patella position was assessed using the Blackburne-Peel Index (BPI) and the Insall-Salvati Ratio (Figure 2). General linear modeling (SPSS) was conducted in order to determine the most significant patient and implant positioning factors on wear rate. Results. After adjustment for creep, the mean volumetric wear rate was 11.6 mm. 3. /yr (Figure 2). According to the linear regression model wear increased with younger age (p=0.0014) and male sex (p<0.001). The wear rate was independent of patient weight (p=0.17). From the multiple positioning factors only BPI and tibial slope were significant and inversely correlated with wear (p=0.009 and 0.026, respectively). The average ISR was normal before and after surgery, whereas the BPI was only in the normal range prior to surgery, and dropped postop into pseudo-baja (p<0.001, Figure 3). Discussion. The effect of male sex on wear volume can partially be explained by a larger average implant size; however, other unknown confounding factors may play a role too. The effect of younger age is likely related to higher patient activity. Based on previous gait analysis, we speculate that increasing tibial slope results in larger AP translations of the knee joint and thus more wear. Interestingly, BPI remained a highly significant factor when controlled for all other factors. The average BPI clearly dropped post-operatively, whereas the average ISR did not, indicating that not true patella baja, but a joint line elevation occurred due to the reconstruction. Joint line elevation may affect the quadriceps mechanism leading to higher contact forces and subsequent higher wear. Post-operative joint line elevation can be explained by the intention to keep bone loss at a minimum, while using thick polyethylene inserts. Further studies are needed to determine the trade-offs between bone conservation and reduction of wear rate. However, this study has revealed the importance of surgical factors regarding polyethylene wear reduction in TKR. Acknowledgements. This study was funded by NIH grant R01AR059843. For figures/tables, please contact authors directly.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_5 | Pages 85 - 85
1 Mar 2017
Pierre D Gilbert J Swaminathan V Yanoso-Scholl L TenHuisen K Lee R
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Statement of Purpose. Mechanically assisted crevice corrosion of modular tapers continues to be a concern in total joint replacements as studies have reported increases in local tissue reactions. 1. Two surgical factors that may effect taper seating mechanics are seating load magnitude and orientation. In this study 12/14 modular taper junctions were seated over a range of loads and loading orientations. The goals of this study were to assess the effects of load magnitude and orientation on seating load-displacement mechanics and to correlate these to the pull-off load. Methods. Ti6Al4V 12/14 tapers and CoCrMo heads were tested axially at four seating load levels (n=5): 1-, 2-, 4- and 8- kN. Three orientation groups were tested at 4 kN (n=5), 0°, 10° and 20°. The load-displacement behavior during testing was captured using data acquisition methods and two non-contact eddy current sensors fixed to the neck, targeting head-neck relative motion (Micro-Epsilon). Loads were ramped (200 N/s) with a servohydraulic system from 0 N to peak load and held for 5s (Instron). Off-axis test samples were oriented in an angled fixture. Displacement and load data were recorded in LabView. Seating displacement was the distance traveled between 50 N and thepeak load. Axial tensile pull-off loads (5 mm/min) were applied until the locking ability of taper junctions failed. Statistical analysis was performed using ANOVA test (P<0.05). Results. Axial tests. Seating load-displacement behavior at different seating loads (Fig. 1) show consistent characteristic behavior. Displacements rise parabolically to the peak load reflecting elastic deformation and rigid-body motion. Unloading is elastic and the y-intercept of the unloading curves reflects seating displacement. Displacement and work of seating for the axial tests (Fig. 2a and 2b, respectively) show that both increase with seating magnitude. Displacement increases approximately linearly, while work increases parabolically with seating load. All groups are significantly different (P<0.05). Pull-off loads (Fig. 3) increase linearly with seating load. Pull-off loads are approximately 44% of the seating load. All loads are statistically different (P<0.05). Off-axis tests. Measured seating displacements were comprised of rigid-body and elastic motion. A stiffness-correction method removed elastic motion. 2. Displacement, work and pull-off at the different seating load orientations were not significantly affected (P>0.05, data not shown). Discussion. Static seating load magnitude and orientation effects on seating mechanics and pull-off loads simulating surgical assembly were quantitatively studied in an instrumented seating test method. Increased seating loads increased work of seating, seating displacement and pull-off load. Such seating plots may assist in better understanding of the design, material, and surgical factors associated with taper locking mechanics. Seating orientation to 20° offset did not significantly affect seating mechanics or pull-off loads. Pull-off loads were about 50% of the seating loads for all cases which is consistent with other work. 3. . Conclusions. Increased seating load magnitude increased seating displacement, work and pull-off loads in 12/14 tapers. Load orientation had no significant effect. For figures/tables, please contact authors directly.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_4 | Pages 81 - 81
1 Apr 2019
Bitter T Marra M Khan I Marriott T Lovelady E Verdonschot N Janssen D
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Introduction. Fretting corrosion at the taper interface of modular connections can be studied using Finite Element (FE) analyses. However, the loading conditions in FE studies are often simplified, or based on generic activity patterns. Using musculoskeletal modeling, subject-specific muscle and joint forces can be calculated, which can then be applied to a FE model for wear predictions. The objective of the current study was to investigate the effect of incorporating more detailed activity patterns on fretting simulations of modular connections. Methods. Using a six-camera motion capture system, synchronized force plates, and 45 optical markers placed on 6 different subjects, data was recorded for three different activities: walking at a comfortable speed, chair rise, and stair climbing. Musculoskeletal models, using the Twente Lower Extremity Model 2.0 implemented in the AnyBody modeling System™ (AnyBody Technology A/S, Aalborg, Denmark; figure1), were used to determine the hip joint forces. Hip forces for the subject with the lowest and highest peak force, as well as averaged hip forces were then applied to an FE model of a modular taper connection (Biomet Type-1 taper with a Ti6Al4V Magnum +9 mm adaptor; Figure 2). During the FE simulations, the taper geometry was updated iteratively to account for material removal due to wear. The wear depth was calculated based on Archard's Law, using contact pressures, micromotions, and a wear factor, which was determined from accelerated fretting experiments. Results. The forces for the comfortable walking speed had the highest peak forces for the maximum peak subject, with a maximum peak force of 3644 N, followed by walking up stairs, with a similar maximum peak force of 3626 N. The chair rise had a lower maximum peak force of 2240 N (−38.5%). The simulated volumetric wear followed the trends seen in the peaks of the predicted hip joint forces, with the largest wear volumes predicted for a comfortable walking speed, followed by the stairs up activity and the chair rise (Figure 3). The subjects with the highest peak forces produced the most volumetric wear in all cases. However, the lowest peak subject had a higher volumetric wear for the stairs up case than the average subject. Discussion. This study explored the effect of subject-specific variations in hip joint loads on taper fretting. The results indicate that taper wear was predominantly affected by the magnitudes of the peak forces, rather than by the orientation of the force. A more comprehensive study, capturing the full spectrum of patient variability, can help identifying parameters that accelerate fretting corrosion. Such a study should also incorporate other sources of variability, including surgical factors such as implant orientation, sizing, and offset. These factors also affect hip joint forces, and can be evaluated in musculoskeletal models such as presented here


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_4 | Pages 139 - 139
1 Apr 2019
Nambu S Chang D
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Objective. Clinical wear depends on several factors such as implant specific factors (material, design, and sterilization), surgical factors/techniques, and patient-specific factors (weights and activities). The load magnitude for wear testing in the standard protocols (i.e., 2 kN as per ASTM F1714 or 3 kN as per ISO 14243-3) represent an average patient weight and does not address the other “what-if”’ scenarios (i.e., wear vs. patient weights, activities, duration, etc.,). The results from in-vitro testing report the data in wear (mg) or wear rate (mg/Mc) and are only applicable to the parameters (i.e., loads, bearing diameter, thickness, etc.,) used for the testing and not suitable to the variations seen in clinical scenarios. Therefore, it is essential to present the wear summary that can normalize the parameters and which is relevant in both in-vitro and in-vivo conditions. The goal of the current study is an attempt to present wear as a parameter (i.e., wear factor that combines the wear test data and established- theoretical relationship) and is thus applicable in both in-vivo and in-vitro scenarios. Methods. Wear factor was first evaluated using actual wear testing conducted on metal on cross-linked polyethylene bearings along with well-established Dowson's wall bridge equation. As per Dowson-Wallbridge, volumetric wear is V=2.376·KNWR+C or K=V/(2.376·NWR) where V is the volumetric wear in mm. 3. , K is the wear factor in mm. 3. /Nmm, N is the number of cycles, W is the load in Newtons, R is the bearing radius in mm, and C is the creep (assumed to be negligible, i.e., C=0 in this model. 28 mm simulator wear was first used to evaluate wear factor, but since simulator wear presented as a mass loss, these results were converted to volumetric wear using the equation. V. =. m. /. ρ. ,. (m is the wear in mg and r is the density of XLPE in mg/mm. 3. (=0.923). The Dowson-Wallbridge equation was then validated for predictive accuracy against actual wear testing on the predecessor THR system. The wear factor thus obtained was used to compute the theoretical-wear for other sizes (i.e., 42 and 46 mm bearings). The theoretical-wear was then compared to simulator wear for predictive accuracy. Results & Discussion. Figure1 below shows the verification of the predictive capability of the Dowson-Wallbridge equation against historical wear data. The theoretical-wear (for 42 and 46 mm bearings) evaluated using wear factor was in good agreement with the simulator wear The results show Dowson's Wallbridge equation was verified and thus can be used to assess the wear factor. The results show that the wear factor for XLPE system is 1.79 × 10. −10. mm. 3. /N-mm. Elfick et al. evaluated the clinical wear factor for 47 retrieved acetabular components with varying diameters, patients, and liner thickness ranging from 1.8 mm (thinnest) to 11.0 mm thick liners using the Dowson-Wallbridge equation and reported the mean wear factor as 1.93 × 10. −9. mm. 3. /N-m. The results of the current evaluation are also in good agreement with clinical studies