A Microsoft HoloLens Mixed Reality Surgical Simulator for Patient-Specific Hip Arthroplasty Training

Surgical simulation can offer novice surgeons an opportunity to practice skills outside the operating theatre in a safe controlled environment. According to literature evidence, nowadays there are very few training simulators available for Hip Arthroplasty (HA). In a previous study we have presented a physical simulator based on a lower torso phantom including a patient-specific hemi-pelvis replica embedded in a soft synthetic foam. This work explores the use of Microsoft HoloLens technology to enrich the physical patient-specific simulation with the implementation of wearable mixed reality functionalities. Our HA multimodal simulator based on mixed reality using the HoloLens is described by illustrating the overall system, and by summarizing the main phases of the design and development. Finally, we present a preliminary qualitative study with seven subjects (5 medical students, and 2 orthopedic surgeons) showing encouraging results that suggest the suitability of the HoloLens for the proposed application. However, further studies need to be conducted to perform a quantitative test of the registration accuracy of the virtual content, and to confirm qualitative results in a larger cohort of subjects

Joint registry approach for identification of outlier prostheses

Background and purposeJoint Replacement Registries play a significant role in monitoring arthroplasty outcomes by publishing data on survivorship of individual prostheses or combinations of prostheses. The difference in outcomes can be device- or non-device-related, and these factors can be analyzed separately. Although registry data indicate that most prostheses have similar outcomes, some have a higher than anticipated rate of revision when compared to all other prostheses in their class. This report outlines how the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) has developed a method to report prostheses with a higher than expected rate of revision. These are referred to as "outlier" prostheses.Material and methodsSince 2004, the AOANJRR has developed a standardized process for identifying outliers. This is based on a 3-stage process consisting of an automated algorithm, an extensive analysis of individual prostheses or combinations by registry staff, and finally a meeting involving a panel from the Australian Orthopaedic Association Arthroplasty Society. Outlier prostheses are listed in the Annual Report as (1) identified but no longer used in Australia, (2) those that have been re-identified and that are still used, and (3) those that are being identified for the first time.Results78 prostheses or prosthesis combinations have been identified as being outliers using this approach (AOANJRR 2011 Annual Report). In addition, 5 conventional hip prostheses were initially identified, but after further analysis no longer met the defined criteria. 1 resurfacing hip prosthesis was initially identified, subsequently removed from the list, and then re-identified the following year when further data were available. All unicompartmental and primary total knee prostheses identified as having a higher than expected rate of revision have continued to be re-identified.InterpretationIt is important that registries use a transparent and accountable process to identify an outlier prosthesis. This paper describes the development, implementation, assessment, and impact of the approach used by the Australian Registry.Richard N de Steiger, Lisa N Miller, David C Davidson, Philip Ryan and Stephen E Grave

Orthopaedic registries: the Australian experience

The Australian Orthopaedic Association National Joint Replacement Registry first began data collection on 1 September 1999 and full nationwide implementation commenced in January 2003.The purpose of the Registry is to improve the quality of care for individuals receiving joint replacement surgery.The Registry enables surgeons, academic institutions, governments and industry to request specific data that are not available in published annual reports.There is an established system for identifying prostheses with a higher than anticipated rate of revision (HTARR) which was introduced in 2004.The higher rate of revision for the ASR Hip Resurfacing System was first identified by this process in 2007.There has been a reduction in revision hip and knee replacement over the years that the Registry has been in operation, and the addition of Patient Reported Outcome Measures (PROMs) and data linkage will enable more extensive analysis of joint replacement surgery in the future. Cite this article: EFORT Open Rev 2019;4 DOI: 10.1302/2058-5241.4.180071

Lower prosthesis-specific 10-year revision rate with crosslinked than with non-crosslinked polyethylene in primary total knee arthroplasty.

BACKGROUND AND PURPOSE: While highly crosslinked polyethylene has shown reduced in vivo wear and lower rates of revision for total hip arthroplasty, there have been few long-term studies on its use in total knee arthroplasty (TKA). We compared the rate of revision of non-crosslinked polyethylene to that of crosslinked polyethylene in patients who underwent TKA for osteoarthritis. PATIENTS AND METHODS: We examined data from the Australian Orthopaedic Association National Joint Replacement Registry on 302,214 primary TKA procedures with non-crosslinked polyethylene and 83,890 procedures with crosslinked polyethylene, all of which were performed for osteoarthritis. The survivorship of the different polyethylenes was estimated using the Kaplan-Meier method and was compared using proportional hazard models. RESULTS: The 10-year cumulative revision rate for non-crosslinked polyethylene was 5.8% (95% CI: 5.7-6.0) and for crosslinked polyethylene it was 3.5% (95% CI: 3.2-3.8) (> 6.5-year HR = 2.2 (1.5-3.1); p < 0.001). There was no effect of surgical volume or method of prosthesis fixation on outcome. There were 4 different TKA designs that had a minimum of 2,500 procedures in at least 1 of the polyethylene groups and a follow-up of ≥ 5 years. 2 of these, the NexGen and the Natural Knee II, had a lower rate of revision for crosslinked polyethylene. The Scorpio NRG/Series 7000 and the Triathlon Knee did not show a lower rate of revision for crosslinked polyethylene. INTERPRETATION: There is a lower rate of revision for crosslinked polyethylene in TKA, and this appears to be prosthesis-specific and when it occurs is most evident in patients < 65 years of age. The difference in revision rates was mainly due to revisions because of lysis and loosening

The effect of patient, fracture and surgery on outcomes of high energy neck of femur fractures in patients aged 15-50

Introduction: High-energy femoral neck fractures in young patients can be devastating, with the risk of osteonecrosis, nonunion, malunion and lifelong morbidity. The aim of this study is to define the effects of patient, fracture and surgical factors on the outcome of high-energy femoral neck fractures in patients aged from 15 to 50 years. Methods: A retrospective review was conducted of high-energy femoral neck fractures in patients aged 15–50 managed surgically at a Level 1 Trauma Centre, using a prospectively recorded trauma database. Low energy trauma (including falls from <1 m), medical conditions adversely affecting bone density, and pathological fractures were excluded. A clinical and radiological review was performed. The primary outcome measures were the development of osteonecrosis or nonunion leading to total hip arthroplasty (THA). Secondary outcome measures included osteotomy or other surgical procedures, quality of reduction and malunion. Results: Thirty-two patients meeting the inclusion criteria were identified between January 2008 and July 2015. The mean follow-up was 58.5 months (range 980–3,048 days). Three patients (9.4%) required THA. No other surgical procedures were performed. None of the 29 other patients developed radiologically apparent osteonecrosis. Fracture type, displacement, anatomical reduction and fixation type were not statistically significant risk factors affecting these outcomes. For all patients, an average of 8% loss of femoral neck height and 10% femoral neck offset were seen. Conclusions: At a mean 4.9-year follow-up, the incidence of high-energy femoral neck fractures leading to THA was 9.4%, as a consequence of osteonecrosis or nonunion. Malunion was common

The effect of patient, fracture and surgery on outcomes of high energy neck of femur fractures in patients aged 15-50

Introduction: High-energy femoral neck fractures in young patients can be devastating, with the risk of osteonecrosis, nonunion, malunion and lifelong morbidity. The aim of this study is to define the effects of patient, fracture and surgical factors on the outcome of high-energy femoral neck fractures in patients aged from 15 to 50 years. Methods: A retrospective review was conducted of high-energy femoral neck fractures in patients aged 15–50 managed surgically at a Level 1 Trauma Centre, using a prospectively recorded trauma database. Low energy trauma (including falls from &lt;1 m), medical conditions adversely affecting bone density, and pathological fractures were excluded. A clinical and radiological review was performed. The primary outcome measures were the development of osteonecrosis or nonunion leading to total hip arthroplasty (THA). Secondary outcome measures included osteotomy or other surgical procedures, quality of reduction and malunion. Results: Thirty-two patients meeting the inclusion criteria were identified between January 2008 and July 2015. The mean follow-up was 58.5 months (range 980–3,048 days). Three patients (9.4%) required THA. No other surgical procedures were performed. None of the 29 other patients developed radiologically apparent osteonecrosis. Fracture type, displacement, anatomical reduction and fixation type were not statistically significant risk factors affecting these outcomes. For all patients, an average of 8% loss of femoral neck height and 10% femoral neck offset were seen. Conclusions: At a mean 4.9-year follow-up, the incidence of high-energy femoral neck fractures leading to THA was 9.4%, as a consequence of osteonecrosis or nonunion. Malunion was common