Conventionally instrumented inverse kinematic alignment for total knee arthroplasty: How is it done?

Purpose: For primary total knee arthroplasty (TKA), there is an increasing trend towards patient-specific alignment strategies such as kinematic alignment (KA) and inverse kinematic alignment (iKA), which by restoring native joint mechanics may yield higher patient satisfaction rates. Second, the most recent Australian joint registry report describes favourable revision rates for conventionally instrumented TKA compared to technology-assisted techniques such as those using navigation, robotics or custom-cutting blocks. The aim of this technique article is to describe in detail a surgical technique for TKA that: (1) utilises the principles of iKA and (2) uses conventionally instrumented guided resections thereby avoiding the use of navigation, robotics or custom blocks. Methods: A TKA technique is described, whereby inverse kinematic principles are utilised and patient-specific alignment is achieved. Additionally, the patellofemoral compartment of the knee is restored to the native patellofemoral joint line. The sequenced technical note provided may be utilised for cemented or cementless components; cruciate retaining or sacrificing designs and for fixed or rotating platforms. Results: An uncomplicated, robust and reproducible technique for TKA is described. Discussion: Knee arthroplasty surgeons may wish to harness the emerging benefits of both a conventionally instrumented technique and a patient-specific alignment strategy. Level of Evidence: Level V.

Inverse kinematic total knee arthroplasty using conventional instrumentation restores constitutional coronal alignment.

PURPOSE: Restricted inverse kinematic alignment (iKA) is a contemporary alignment strategy for total knee arthroplasty (TKA), commonly performed with robotic assistance. While superior clinical results are reported for kinematic-type alignment strategies, registry data indicate no survivorship benefit for navigation or robotic assistance. This study aimed to determine the efficacy of an instrumented, restricted iKA technique for achieving patient-specific alignment. METHODS: Seventy-nine patients undergoing 84 TKAs (five bilateral procedures) using an iKA technique were included for preoperative and postoperative lower limb alignment analysis. The mean age was 66.5 (range: 43-82) with 33 male and 51 female patients. Artificial intelligence was employed for radiographic measurements. Alignment profiles were classified using the Coronal Plane Alignment of the Knee (CPAK) system. Preoperative and postoperative alignment profiles were compared with subanalyses for preoperative valgus, neutral and varus profiles. RESULTS: The mean joint-line convergence angle (JLCA) reduced from 2.5° to -0.1° postoperatively. The mean lateral distal femoral angle (LDFA) remained unchanged postoperatively, while the mean medial proximal tibial angle (MPTA) increased by 2.5° (p = 0.001). By preservation of the LDFA and restoration of the MPTA, the mean hip knee ankle angle (HKA) moved through 3.5° varus to 1.2° valgus. The CPAK system was used to visually depict changes in alignment profiles for preoperative valgus, neutral and varus knees; with 63% of patients observing an interval change in classification. CONCLUSION: Encouraged by the latest evidence supporting both conventional instrumentation and kinematic-type TKA strategies, this study describes how a restricted, conventionally instrumented iKA technique may be utilised to restore constitutional lower limb alignment. LEVEL OF EVIDENCE: Level III.

The Irish National Orthopaedic Register Under Cyberattack: What Happened, and What Were the Consequences?

BACKGROUND: On May 14, 2021, a criminal cyberattack was launched against the Irish public healthcare system, the Health Service Executive, resulting in a complete shutdown of all national healthcare computer systems, including the Irish National Orthopaedic Register (INOR). Cyberattacks of this kind occur sporadically, and postevent analyses can inform future preparedness efforts, but few such analyses have been published. QUESTION/PURPOSE: What was the impact of the cyberattack in terms of (1) registry downtime, (2) harms to patients, and (3) costs to the INOR for data contingency and reconciliation? METHODS: All nine hospitals using the INOR were included for data collection. Since establishment in 2014, the INOR has been rolled out to all eight public elective hospitals, capturing all hip and knee arthroplasty procedures. One private hospital was also captured, with plans to expand the private sector coverage. Individual institutional records and central INOR records were queried with respect to downtime, potential harms to patients (including intraoperative complications because of a lack of data on existing implanted components and complications directly attributed to delayed or canceled procedures), and costs related to additional person-hours addressing data reconciliation. Objective data directly related to the uncontrolled INOR downtime were collected, including duration of downtime, contingency methods employed, quality of contingency data collected, adverse patient events, methods of data salvage and reconciliation, and the cost of data contingency and reconciliation measures. Costs were estimated by the additional person-hours of work completed, multiplied by the hourly rate of that employee. Employees at each of the nine hospitals were asked to provide their additional person-hours of work performed because of the attack. These hours were corroborated by observing the time taken at each unit to reconcile data for single cases multiplied by the number of cases at that unit. Employees included nurses, clinical nurse specialists, and doctors of various grades. Person-hour rates were calculated using the Health Service Executive's published salary scales. RESULTS: The INOR suffered a median downtime of 134 days (range 119 to 272 days) across nine sites. No serious adverse patient events were identified. The immediate implementation of a paperwork fallback method for the INOR successfully resulted in 100% case capture during the downtime. However, 2850 additional person-hours were required for data reconciliation at an estimated cost of USD 181,000 to USD 216,000. More subjectively, as reported by interviews with INOR leads at each hospital, the cyberattack negatively impacted operating room efficiency with delays between procedures because of additional paperwork data collection, disrupted patient flow for paperwork data collection on the ward level and in the outpatient clinics, and disrupted resource allocations and staff capabilities because of additional paperwork requirements during the contingency period. CONCLUSION: Disruptions to data collection and data accessibility after this cyberattack were successfully countered by a contingency plan; however, substantial financial costs and additional resources were required for data conservation and reconciliation. CLINICAL RELEVANCE: In addition to robust preventative security measures, national registers and other healthcare systems should have secondary data backup facilities and reliable fallback procedures prepared for such events.

A simple method to rapidly assess the tibial tuberosity-trochlear groove distance using computed tomography.

BACKGROUND: The tibial tuberosity-trochlear groove (TTTG) distance is used to assess patellofemoral instability (PFI) and the likelihood of the development of patellofemoral disorders. The current gold standard in the assessment of the TTTG is computed tomography (CT) or magnetic resonance imaging (MRI). The current image software used for viewing these CT images does not allow for easy assessment of the TTTG. AIMS: This study presents a simple method to measure the TTTG on any image software, utilizing easily available and affordable stationary. METHODS: Four consecutive patients with no known knee pathologies were selected from recent studies at our institution. Their TTTGs were measured using this study's method and validated using the standard, freely available image analysis software Fiji. Pre-defined anatomical landmarks were located and marked using adhesive pieces of paper. The TTTG was defined as the distance between parallel lines through the apex of the tibial tuberosity and trough of the trochlear groove, where each of these lines is perpendicular to the Dorsal Condylar Line. RESULTS: The TTTG measured using this study's method was found to be in agreement with the measurements made using Fiji software. CONCLUSIONS: This study demonstrates that the TTTG can be simply and quickly assessed using readily available and affordable stationery, without the need for expensive or complex secondary analysis software. This could allow for the assessment of PFI in the outpatient clinic whilst the patient is present, offering valuable assistance to the orthopaedic surgeon in clinical decision making.

Can Bar Code Scanning Improve Data Capture in a National Register? Findings from the Irish National Orthopaedic Register.

BACKGROUND: The Irish National Orthopaedic Register (INOR) provides a national mechanism for managing data on THA and TKA in Ireland, including a detailed implant record populated by intraoperative implant bar code scanning. It is critically important that implant details are recorded accurately for longitudinal outcome studies, implant recalls, and revision surgery planning. Before INOR's 2014 launch, Irish hospitals maintained separate, local institutional arthroplasty databases. These individual databases typically took the form of hardcopy operating room (OR) logbooks with handwritten patient details alongside the descriptive stickers from the implant packaging and/or individual institution electronic records using manual electronic implant data input. With the introduction of the INOR, a single, unifying national database was established with the ability to instead collect implant data using bar code scanning at time of implant unpackaging in the OR. We observed that bar code data entry represented a novel and potentially substantial change to implant recording methods at our institution and so sought to examine the potential effect on implant data quality. QUESTIONS/PURPOSES: We compared the new bar code scanning method of implant data collection used by the INOR to the previously employed recording methods at our institution (in our case, the previous methods included both an electronic operation note database [Bluespier software] and a duplicate hardcopy OR logbook) and asked (1) Does bar code scanning improve the completeness of implant records? (2) Does bar code scanning improve the accuracy of implant records? METHODS: Although the INOR was launched in 2014, our institution went live with it in 2019. To avoid any potential recording issues that may have occurred during the 2019 introduction of the novel system, a clear period before the introduction of INOR was selected at our institution to represent an era of manual data input to Bluespier software: July 2018. Although we initially aimed for 2 months of data from July 1, 2018, to August 31, 2018 (n = 247), we decided to proceed to 250 consecutive, primary THAs or TKAs for clarity of results. No procedure meeting these criteria was excluded. A second recent period, January 2021, was identified to represent an era of bar code data input; 250 consecutive, primary THAs or TKAs were also included from this date (to February 15, 2021). No case meeting these criteria was excluded. A total of 4244 implant parameters from these 500 primary THAs or TKAs were manually cross-referenced for missing or incorrect data. Eleven THA and six TKA parameters were chosen for comparison, including implant names and component sizes. For each case, either the 2018 Bluespier electronic record or the 2021 INOR electronic record was manually interrogated, and implant details were recorded by two authors before they were compared against the duplicate record for every case (the reference-standard OR logbook containing the corresponding implant product stickers) for both completeness and accuracy. Completeness was defined binarily as the implant parameter being either present or absent; we did likewise for accuracy, either that parameter was correct or incorrect. The OR logbooks were chosen as the reference standard because we felt the risk of product stickers containing errors (inaccuracies) was negligible, and in our collective experience, missing stickers (incompleteness) has not been encountered. Logbook case completeness was also confirmed by comparison to our inpatient management system. RESULTS: With the introduction of the automated bar code data entry in the INOR, the proportion of missing data declined from 7% (135 of 2051) to 0% (0 of 2193), and the proportion of incorrectly recorded implant parameters declined from 2% (45 of 2051) to 0% (0 of 2193). The proportion of procedures with entirely accurate implant records rose from 53% (133 of 250) to 100% (250 of 250). CONCLUSION: The completeness and accuracy of implant data capture was improved after the introduction of a contemporary electronic national arthroplasty registry that utilizes bar code data entry. CLINICAL RELEVANCE: Based on the results of this study, other local and national registers may consider bar code data entry in the OR to achieve excellent implant data quality. Future studies may examine implant data quality at a national level to validate the bar code-populated data of the INOR.

CT versus MRI planning for reverse geometry total shoulder arthroplasty.

INTRODUCTION: Preoperative planning for Reverse Total Shoulder Arthroplasty (RTSA) using CT or MRI is well described.1, 2, 3, 4, 5, 6, 7 We aimed to compare pre-operative CT versus MRI measurement accuracy for predicting intra-operative glenoid implant sizing. METHODS: All patients with a preoperative CT or MRI undergoing RTSA at our tertiary referral center from October 2017 to February 2020 were included. Data was collected from theatre and implant registers. Glenosphere Width (GW) and Baseplate Central Screw Length (BCSL) were independently predicted from pre-operative CT or MRI imaging by 2 blinded senior authors. A sub-group analysis was also performed between trauma and non-trauma CT cases. SPSS v26 was used for statistical comparison between predicted and actual implants. RESULTS: 71 data sets from 69 patients were included for analysis: 31 CT predictions and 40 MRI predictions. 61.3% of CT measured GW predictions were accurate compared to 82.5% of MRI predictions (p = 0.045). BCSL predictions were 77.4% and 70% accurate for CT and MRI respectively, without significant difference. There was no significant difference in sub-group analysis for trauma vs elective CT accuracy of BCSL or GW measurements. CONCLUSION: MRI imaging may be superior to CT for predicting GW and no less accurate than CT for predicting BCSL in the elective setting. No difference in CT measurement accuracy was seen between trauma and elective settings. While simultaneously clearly defining shoulder soft tissue anatomy, MRI may also be the preferred modality for bony measurements during pre-operative planning for elective RTSA.

Trabecular Metal Augments for Severe Acetabular Defects in Revision Hip Arthroplasty: A Long-Term Follow-Up.

BACKGROUND: Paprosky type IIIa and IIIb acetabular defects remain technically challenging during revision hip arthroplasty. Numerous surgical options exist to counter extensive acetabular bone loss with high postoperative complication and revision rates reported. Our aim was to report comprehensive long-term outcomes of our experience with Trabecular Metal (TM) augments for these difficult cases. METHODS: 38 patients underwent revision total hip arthroplasty at our institution from 2009 to 2014 where a TM augment was used for acetabular deficiency. Prospective radiographic and Patient-Reported Outcome Measures were recorded and analyzed to a mean of 7.3 years (range: 5.4 to 10.8). RESULTS: No patient was excluded or lost to follow-up. Complications included 3 intraoperative fractures, 1 early infection requiring washout with implant retention, 1 early revision due to allograft resorption, and 6 patients who required late repeat revision surgery: 3 for late infection, 2 for aseptic loosening with augment fracture or dislocation, and 1 for recurrent dislocation. The estimated mean implant survivorship was 8.99 years. 93.5% of augments remaining were well osseointegrated while 97% of the acetabular shells were osseointegrated. Hip center of rotation was restored by a mean of 14 mm inferiorly without significant medialization. Short Form-12 (SF-12) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were significantly reduced postoperatively to a level comparable to the average individual. CONCLUSION: This long-term study details our experience of TM augments for the most severe acetabular defects. For such cases, no excellent surgical solution exists; in comparison to alternative methods, we advocate that this technique is reasonably safe and effective.