BOA Annual Congress 2026

Title
Fixed- Bearing Unicompartmental Knee Arthoplasty: The Super Heavyweight Champion

Jason Jia Shyan Ong1, Francisco Barbosa1, Navjot Bhangoo1, Robert Straw1, Guido Geutjens1 

Affiliation
1University Hospitals Derby & Burton Foundation Trust, Uttoxeter Road, Derby DE22 3NE 

Abstract 

Background
Morbid obesity (body mass index [BMI] ≥40 kg/m²) is increasingly prevalent among patients undergoing knee arthroplasty. Although unicompartmental knee arthroplasty (UKA) offers functional advantages and outcomes comparable to those in non-obese and class I obese patients, its use in class III morbidly obese individuals remains controversial. Many surgeons continue to regard severe obesity as a relative or absolute contraindication, and evidence evaluating outcomes in this population remains limited. This study aimed to evaluate implant survivorship, revision rates, complications, and functional recovery following fixed-bearing medial UKA in patients with BMI ≥40 kg/m². 

Methods
A single-centre, retrospective cohort study was conducted on 135 consecutive UKA procedures undertaken in patients with BMI ≥ 40 kg/m² between January 2015 and December 2025. Mobile-bearing, lateral compartment, and patellofemoral UKA were excluded. The final cohort comprised 114 fixed-bearing medial UKA. Implant survivorship was analysed using Kaplan–Meier survival analysis with revision for any reason as the endpoint. Restricted mean survival time (RMST) was calculated. Secondary outcomes included postoperative complications and range of motion (ROM). 

Results
The mean age was 59.8 ± 9.0 years, and mean BMI was 43.5 ± 4.6 kg/m². Median follow-up was 5.8 years (95% CI 5.2–6.4), with a maximum follow-up of 10.8 years. Kaplan–Meier analysis demonstrated 5-year implant survivorship of 96.7% (95% CI 93.0–100%). RMST to 5 years was 4.91 years. Three knees (2.6%) underwent revision, including one conversion to total knee arthroplasty for progressive osteoarthritis and two revisions for infection. Four postoperative complications (3.5%) occurred within 90 days. Improvement in postoperative ROM was observed in 86.2% of knees, with correction of all pre-operative fixed flexion deformities. 

Conclusion
Fixed-bearing medial UKA in patients with BMI ≥40 kg/m² demonstrated excellent mid-term survivorship with low revision and complication rates. Morbid obesity alone should not preclude consideration of fixed-bearing medial UKA in appropriately selected patients. 

Mind Over Fracture: Early Delirium Detection in Hip Fracture Surgery

Introduction
Delirium in hip fracture patients has been shown to lead to poorer outcomes including delayed mobilization, longer length of hospital stays and lower likelihood of returning home on discharge. The Scottish Hip Fracture Audit states delirium screening should be undertaken on arrival to ED, within 24 hours of admission and within 72 hours post op. The 4AT test is a common and well validated tool for delirium assessment.

Aims
Primary outcome was to improve 4AT usage and documentation in the post-operative phase. Secondary outcomes were to identify patients at higher risk of delirium, its effect on the length of stay and any association between anaesthetic or procedure type. 

Methods
The 4AT tool was added to the pro-forma used by junior doctors in August 2025. Patients who underwent a procedure following a hip fracture in July and September 2025 were included using etrauma to identify them retrospectively. Operative type and anaesthetic method were recorded from notes. Ekora was then used to assess 4AT scores in the post-operative period alongside assessment of their patient journey, recorded delirium and length of stay.

Results
Post-operative 4AT documentation was improved from 0% to 96.7%. Average length of stay in the delirious group rose by 33% to 20 days. Average CFS score was 5.5 (+/-1) in the delirious cohort, higher than control at 4.1 (+/-1.5). In the delirious group, 61% of patients underwent hemiarthroplasty. General anaesthesia appears weakly associated with delirium. A higher CFS score was associated with higher delirium risk.

Conclusion
The planned intervention resulted in significant change to practice and documentation. Anaesthesia and surgery related findings are contrary to that of the literature and require a larger sample size to provide further clarity. With continued work and intervention, we hope to improve early identification of vulnerable patients and target resources mor

Title
The Grip Gap: Ergonomic Mismatch in Orthopaedic Cement Gun Design 

Maria Choi, Stepping Hill Hospital, Stockport NHS Foundation Trust , John Ferns, Salford Royal Hospital, Northern Care Alliance NHS Trust, Simon Reuben, Stepping Hill Hospital, Stockport NHS Foundation Trust , North West Orthopaedic Research Collaborate (NWORC), David Flaherty, Tameside Hospital, Tameside and Glossop Integrated Care NHS Foundation Trust , Matthew Langstroth, Royal Blackburn Hospital, East Lancashire Hospitals NHS Trust, Raj Pradhan, Blackpool Victoria Hospital, Blackpool Teaching Hospitals NHS Foundation Trust, Gareth Rogers, Royal Bolton Hospital, Bolton NHS Foundation Trust, Sinead Cabezon, Royal Preston Hospital, Lancashire Teaching Hospitals NHS Foundation Trust 

Aims 
Despite a changing and increasingly diverse surgical workforce, many orthopaedic instruments remain unchanged in design. The orthopaedic cement gun is one such tool whose basic form has remained static for decades. This study aimed to compare commonly available cement gun designs, quantify the force required to deliver cement, and relate these demands to surgeons’ grip strength and hand dimensions. 

Methods 
Three commercially available cement guns were tested under controlled, reproducible conditions. A dynamometer measured the force required to fully depress the trigger of a loaded cement gun at defined time points during the working phase of cement. Orthopaedic registrars and consultants participated in hand metric measurement and maximal grip strength testing using a  dynamometer. 

Results 
There was a considerable difference in trigger force between cement guns, with a consistent force requirement difference of at least 57% between the best and worst-performing  guns.  Seventy-six surgeons participated in grip strength testing, with a mean maximal grip strength of 49 [27-82] kg-force. Female gender was associated with lower maximal grip strength (p<0.001). There was a significant positive correlation between maximal grip strength and metrics including glove size, hand length, hand width, middle finger length, and hand span.  

Conclusion 
Substantial variation exists between cement gun designs, which bears impact on their effective use. Female surgeons and those with smaller hands will be disproportionately affected. As the demographics of the orthopaedic workforce evolve, manufacturers should prioritise ergonomically adaptable designs to make instruments more inclusive to the modern surgeon cohort.  

Utilisation and diagnostic performance of the ‘SuCESS’ cauda equina triage tool in a UK district general hospital

Authors and Affiliations
T. Poliacik¹, T. Fowles² , C. Gunn¹, R. Chhabria¹, F. Al‑Mahdawi¹, R. Thonse¹, ¹Countess of Chester Hospital NHS Foundation Trust, UK (Trauma & Orthopaedics)

² School of Medicine, University of Liverpool, Liverpool, UK (fifth year medical student)

Abstract

Aims
To evaluate the performance of the SuCESS tool for predicting decompression‑confirmed cauda equina syndrome (CES) in a UK district general hospital (DGH) emergency department setting.

Methods
This retrospective single centre study included all adults presenting with suspected CES between 1 January 2023 and 31 December 2025 to the emergency department of a single DGH. Patients were identified from emergency department coding and MRI requests. Clinical variables required for SuCESS were extracted from electronic records using a predefined proforma, before reviewing MRI or operative findings to reduce bias. Decompression‑confirmed CES served as the reference standard. SuCESS scores were calculated, and discrimination was assessed using the area under the receiver operating characteristic curve (AUC), with prespecified sensitivity analyses to explore the impact of missing data.

Results
A total of 453 patients with suspected CES were identified, including 29 decompression-confirmed CES cases. 70 patients were missing one or more variables. The complete-case cohort comprised 383 patients, including 26 CES and 357 non-CES cases. At a SuCESS threshold of 3 or more, the complete-case analysis yielded 21 true positives, 5 false negatives, 117 false positives, and 240 true negatives, corresponding to sensitivity 80.8%, specificity 67.2%, positive predictive value 15.2%, negative predictive value 98.0%, positive likelihood ratio 2.46, negative likelihood ratio 0.29, and accuracy 68.1%. ROC analysis of the complete-case cohort demonstrated an AUC of 0.78. Three decompressed CES cases had incomplete documentation with two missing only one variable.

Conclusion
In this DGH cohort, SuCESS retained high rule-out performance but did not reproduce the perfect sensitivity reported in the original tertiary-centre study. The score appears useful as a structured assessment aid but should not be used in isolation to exclude CES or determine MRI acquisition.

 

Title
The Impact of Malrotating the Proximal Femoral Fragment During a Dynamic Hip Screw 

Introduction
Dynamic Hip Screw (DHS) fixation is one of the most common operations performed in orthopaedic trauma. However, rotational torque during screw insertion can result in clockwise rotation of the proximal femoral fragment, particularly in left sided fractures. This study aimed to quantify the effect of proximal fragment malrotation on the contact area between fracture fragments. 

Methods
Four femoral STL models were obtained from the National Institute of Health 3D print exchange. A total of 24 fractures (12 right-sided and 12 left-sided), classified as AO A1, were created using 3D modelling software. The proximal fragment was rotated clockwise about a defined axis corresponding to a 135° DHS trajectory. Tolerance-based contact area (≤ 1mm) was quantified at 1° increments using closest-point-to-triangle distances. 

Results
Tolerance-based contact area decreased nonlinearly with rotation. Contact was largely preserved with the first few degrees of rotation; however, beyond 3° of malrotation a rapid decline in contact area was observed. At 10° of rotation, contact area decreased by 36% [95% CI 21,43] in both left- and right-sided fractures. Proximal fractures demonstrated greater sensitivity to rotation, when compared to distal fractures.   

Conclusions
Rotation of the proximal fragment results in a nonlinear reduction in contact area. Rapid deterioration in contact area occurs after 3° of malrotation. This highlights the need for careful screening of the proximal fragment during screw placement and consideration of a de-rotational screw or wire. 

Lifetime Economic Modelling of Trans-Femoral Direct Skeletal Fixation Within the

National Health Service

Authors: Handford, C. Toderita, D. McMenemy, L. Ramasamy, A. Bull, A.

Presenting Author: Major Charles Handford

Presenting Author Stage of Training: ST8

Aims
To evaluate whether trans-femoral direct skeletal fixation (TF-DSF) over a lifetime provides a cost-effective treatment strategy within the National Health Service (NHS) for those who are problematic socket suspended prosthetic (SSP) users.

Methods
Three treatment arms were compared: continued SSP, TF-DSF, or wheelchair use. United Kingdom (U.K.) military veterans, with prospective data collection, who underwent TF-DSF (n=21; mean implantation age 36 years; 14 bilateral, 7 unilateral) provided data for base case analysis. Incomplete data was primarily substituted with reported outcomes from peer reviewed published literature. A lifetime Markov model was constructed with 1-year cycles. Probabilistic and deterministic analysis was undertaken.

Results
TF-DSF had the highest cost (£154,988.66) and greatest effectiveness (14.25 QALYs). The incremental cost effectiveness ratio for TF-DSF was £34,097.54/quality adjusted life year (QALY) versus wheelchair use and £29,090.51/QALY versus problematic SSP. Continued SSP use was extendedly dominated throughout. Wheelchair use was the least costly (£5,434.74) but least effective (9.87 QALYs). The cost effectiveness acceptability curve showed TF-DSF is the preferred option above a willingness to pay £30,000/QALY and exceeds 50% probability of cost-effectiveness by £35,000/QALY.

Conclusion
This is the first study modelled specifically for treatment within the NHS. It is also the first study to directly compare all three treatment arms. The evidence suggests that TF-DSF is a cost-effective solution for patients who fail to ambulate on SSP. The NHS should reconsider the current position on commissioning of this service based on this evidence. TF-DSF should only be undertaken within specialist centralised units with a focus on prospective data collection and sound governance. Global collaboration, in the form of a TF-DSF registry, must be considered. This would facilitate collection of outcome data, at a large volume, which will be vital for ongoing service development.

Referral Pathway Determines Diagnostic Delay in Bone and Soft Tissue Sarcoma: A Retrospective Cohort Study

Abstract Background
Bone and soft tissue sarcomas are rare malignancies in which delayed diagnosis is associated with poorer outcomes. Despite NICE guidance recommending urgent referral for suspected sarcoma, diagnostic delays remain common. This study evaluated the effect of referral pathway on time to specialist assessment and definitive treatment at a Scottish tertiary sarcoma centre.

Methods
A retrospective cohort study was conducted at Aberdeen Royal Infirmary between 2015 and 2022. Patients with histologically confirmed bone or soft tissue sarcoma were included. Patients with incomplete records or palliative management were excluded. Referral pathways were classified into four groups: urgent GP referral directly to the tertiary centre, non-urgent GP referral directly to the tertiary centre, urgent referral to another secondary care centre prior to onward referral, and referral to alternative specialties before sarcoma referral. Primary outcomes were time from first GP presentation to specialist clinic review and definitive treatment. Time intervals were analysed using descriptive statistics and Kruskal–Wallis testing.

Results
Fifty-eight patients were included. Median time to specialist clinic review was shortest in patients referred urgently directly to Aberdeen Royal Infirmary (23 days, IQR 19.5) and longest in those referred initially to other specialties (188 days, IQR 198). Median time to definitive treatment was 66 days (IQR 101) for urgent direct referrals, 120 days (IQR 116) for urgent referrals via other secondary care centres, 124.5 days (IQR 114) for non-urgent referrals and 279.5 days (IQR 166) for referrals through alternative specialties. Significant differences were observed between referral pathways for both time to specialist review (p=0.0019) and total time to treatment (p=0.0026).

Conclusion
Referral pathway significantly influences diagnostic delay in sarcoma. Urgent referral to specialist services was associated with earlier assessment and shorter time to treatment.

Title
Combined Fragility Fractures of the Femur and  Humerus in the Elderly confers increased risk of early  inpatient and 30-day mortality

Abstract
Background: To evaluate mortality outcomes and hospital length of stay in elderly patients  with combined fragility fractures of the femur and humerus (Combined Fracture group)  compared to isolated femoral fractures (Isolated Fracture group).

Methods
A retrospective case-control study was performed using data from two trauma units between January 2018 and 2024. Patients aged ≥60 years with concurrent femur and  humerus fractures were identified and matched to controls with isolated femur fractures by age, sex, ASA score, pre-admission residence, and mobility. Outcomes included inpatient, 30-day and 1-year mortality rates and duration of hospital admission 

Results
Fifty-six patients with combined fractures of humerus and femur were matched to 224 controls with isolated femur fractures. The Combined Fracture group had higher inpatient mortality (17.9 % vs. 7.1%, p=0.02) and 30-day mortality (14.3 % vs. 5.4 %, p=0.037). Mortality at 1 year was higher in the combined group (35.7% vs. 26.3%) but not statistically significant (p=0.184). There was no significant difference in length of hospital stay.

Conclusion
Combined fragility fractures of the femur and humerus are associated with increased short-term mortality compared to isolated femoral fractures. These findings highlight the importance of early identification, tailored multidisciplinary management, and consideration of surgical treatment of humeral fractures to optimise outcomes.

Keywords
Fragility fractures, mortality outcomes, and length of stay

Statements and Declarations
The authors have no competing interests to declare that are relevant to the content of this article. 

Structural Properties of the Deep Medial Collateral Ligament
Super JT, Murray IR, Wilebski BJ, Carlson MR, Retzer NK, Tollefson LV, Gaye CE,
LaPrade CM, LaPrade RF

Investigation performed at Twin Cities Orthopedics, Edina, MN, USA

Background:
The deep medial collateral ligament (dMCL) has traditionally been described as a capsular thickening deep to the superficial medial collateral ligament;
however, recent studies suggest a more extensive anteromedial course with a more important role in knee stability. Despite this, its structural properties remain
incompletely described.

Purpose:
To quantify the structural properties of the dMCL, including load to failure, stiffness, and displacement, to inform surgical strategies and graft selection for medial
knee reconstructions.

Methods: Ten fresh-frozen cadaveric knees (mean age, 63.4 +/- 4.7 years) were
dissected to isolate the dMCL while preserving its meniscofemoral and meniscotibial
attachments. Specimens were mounted in a 6-degree-of-freedom robotic system,
subjected to preconditioning, and then uniaxial load-to-failure testing. Load,
displacement, and failure location were recorded.

Results:
The mean load to failure of the dMCL was 242.9+86.6 N, with a mean stiffness of 25.3414.3 N/mm, and a mean displacement at failure of 15.0+6.6 mm.
Failure occurred predominantly within the meniscotibial portion (9 of 10 specimens), with only one failure in the meniscofemoral portion. None of the specimens failed at the femoral or tibial attachments.

Conclusion:
The dMCL demonstrates clinically relevant structural properties that are greater than previously reported when its expanded anteromedial course is considered.
Quantification of the structural properties of the dMCL provide a biomechanical basis for surgical reconstruction and fixation strategies. These data may assist in graft
selection and fixation strength requirements in anatomic medial knee reconstructions, particularly in patients with anteromedial rotatory instability.

ImplantIQx: Never Never Event

M. Elsheikh1,2,3 , M. Raghavendra2 , D. Bhaskar2 1Surgical Intelligence Labs, United Kingdom 2Glan Clwyd Hospital, Wales, UK 3Health Education Improvement Wales (HEIW), Wales, UK

Introduction
Implantation of incompatible orthopaedic component combinations is a recognised NHS Never Event. NHS England reported over 60 incidents of wrong implant or prosthesis implantation between 2019 and 2024, each associated with unplanned reoperation, prolonged morbidity, and significant medico-legal consequence. Intraoperative verification currently relies on manual cross-referencing by scrub practitioners — a process vulnerable to distraction, time pressure, and incomplete knowledge of cross-manufacturer compatibility constraints. The UK Medical Devices Regulation 2022 mandates machine-readable GS1 barcodes on all implant packaging, yet this data remains unexploited at the point of care.

Methods
ImplantIQx is a cross-platform Software providing real-time, barcode-driven implant compatibility verification in the operating theatre. The application scans GS1-128, DataMatrix, or QR Code symbologies from implant packaging, extracting GTIN-14 product identifiers alongside lot number, expiry date, and serial number via GS1 Application Identifier parsing. Compatibility is evaluated against four sequential rule categories: (i) crossmanufacturer verification, (ii) taper interface geometry matching, (iii) bearing diameter matching, and (iv) active field safety notice status. Results are returned as COMPATIBLE or INCOMPATIBLE with specific corrective action guidance. An immutable audit trail is generated per session, and National Joint Registry minimum dataset fields are automatically pre-populated from scanned component data. The application is currently undergoing single-centre pilot evaluation across hip and knee arthroplasty pathways. A structured validation protocol was conducted using component assemblies from four major UK implant manufacturers (DePuy Synthes, Stryker, Smith & Nephew, Zimmer Biomet), incorporating compatible and intentionally incompatible combinations across all four rule categories.

Results
ImplantIQx achieved an incompatibility detection rate of 100% in pilot evaluation, with no false negative results recorded. All incompatible component combinations — including cross-manufacturer mismatches, taper interface violations, bearing diameter conflicts, and field safety notice-affected components — were correctly identified and flagged with specific corrective action guidance. Full prospective quantitative performance metrics, usability assessment, and theatre workflow integration data are being collected as the pilot progresses.

Conclusions
ImplantIQx provides rapid, accurate point-of-care implant compatibility verification, directly addressing a recognised Never Event by leveraging existing UDI barcode infrastructure already present on all implant packaging. Early pilot data demonstrates 100% incompatibility detection with no false negatives. The application requires no hardware modification to existing theatre workflows, is immediately deployable on standard PCs, and simultaneously reduces National Joint Registry documentation burden. Multicentre prospective evaluation is planned.

Restriction in practice for hallux valgus and hallux rigidus surgery: a national survey of members of the British Foot & Ankle Society.

Cat Malik, Zeid Morcos (presenter), Richard Dimock, Robin Elliot, Daniel Marsland

Introduction
Historically, hallux valgus (HV) surgery has been classified as a Procedure of Limited Clinical Value (PLCV) by the Hampshire and Isle of Wight Integrated Care Board (HIOW ICB), with funding granted when patients met predefined criteria. Since September 2025, funding policy has changed from “prior approval” to “not normally funded,” with hallux rigidus (HR) surgery newly included. Approval for HV and HR surgery now requires patients to be deemed “exceptional,” necessitating submission of an individual funding request (IFR) reviewed by a panel. This study aimed to evaluate the extent of restriction to HV and HR surgery across the United Kingdom and assess the wider implications.

Methods
An online survey of foot and ankle surgeons was conducted through the British Orthopaedic Foot and Ankle Society (BOFAS). The survey was distributed via email and WhatsApp, with responses collected using Microsoft Teams Forms.

Results
Sixty surgeons from 13 regions responded. Overall, 35% (21/60) required some form of authorisation prior to HV surgery; of these, 41% (9/21) required an IFR, representing 15% (9/60) of all respondents. For HR surgery, 26% (16/60) required authorisation and 10% (6/60) required an IFR. IFR restrictions were predominantly reported by HIOW surgeons. Reports from London and the South West were not supported by publicly available ICB policies, which continued to allow criteria-based access. Notably, 89% of surgeons were unaware of how to challenge PLCV policies.

Conclusion
These findings highlight concerns regarding healthcare rationing, transparency, and regional inequity in access to surgery. The HIOW ICB policy differs from other UK regions and appears inconsistent with NHS constitutional principles and NICE guidance. Further national-level review may be required to support equitable, evidence-based patient care.

Counting mismatches in scoliosis surgery for adolescent idiopathic scoliosis, it is more common than you think. 

Authors: Morley HL, Adeyemi T, Khan A, Jaan S, Borse V, Khan A, Loughenbury P, Rao A, Gummerson N, Adsul N 

Patient’s presenting with adolescent idiopathic scoliosis (AIS) can also have rib and vertebral anomalies (1,2). Although to date these factors have not been implicated in the formation of the scoliosis; mismatches can cause dilemmas in surgical planning, reporting and subsequent revision surgery if needed as an adult.  

The aim of this study was to assess the incidence of counting mismatches in our population, as well as, commonly occurring anatomical variants in the UK AIS population.  

A retrospective review was conducted upon 5 years of cases undergoing corrective surgery for AIS in a large tertiary spinal centre based in the UK.  

171 cases were eligible. Rib or vertebral anomalies were identified in 20 cases (11.7%). Lumbosacral vertebrae were found in 3 of our cohort (1.6%). Surgical counting mismatches were found in 13 cases (7.6%). Of those identified, counting mismatches represented one level only. The most common mismatch was a failure to identify 11 thoracic vertebrae and 6 lumbar vertebrae by both the radiology and surgical team.  

The percentage of rib and vertebral anomalies found in our study complements other published work (1,2). Unlike previously published research, there was no statistically significant difference in the proportion or rib or vertebral anomalies presenting in males compared to females. There was a lower incidence of lumbosacral transitional vertebrae in our cohort compared to other studies.  

Whilst analysing the data, the authors observed an association between an absence of counting mismatches in cases where a structured digital planning tool was used. This did not reach statistical significance. However, the tool had only been introduced by one surgeon part way through the data. The authors hypothesise that the structured digital planning tool may reduce mismatches by forcing deliberate, explicit, level-by-level counting and rendering the anatomy, including the ribs, visually. The resultant effect being akin to a surgical checklist (3). The authors feel such a tool warrants further investigation.  

The authors wish to highlight the common nature of mismatches and believe that this represents a significant risk for medical error during primary and subsequent revision surgery, if required. The authors plan to further investigate the effect of introducing a structured digital planning tool to map the anatomy, to determine if this can reduce counting mismatches in scoliosis surgery for AIS.  

 

References 

1. Ibrahim DA, Myung KS, Skaggs DL. Ten percent of patients with adolescent idiopathic scoliosis have variations in the number of thoracic or lumbar vertebrae. JBJS. 2013 May 1;95(9):828-33. 

2. Hu Z, Zhang Z, Zhao Z, Zhu Z, Liu Z, Qiu Y. A neglected point in surgical treatment of adolescent idiopathic scoliosis: Variations in the number of vertebrae. Medicine (Baltimore). 2016 Aug;95(34):e4682. doi: 10.1097/MD.0000000000004682. PMID: 27559975; PMCID: PMC5400342. 

3. Borchard A, Schwappach DL, Barbir A, Bezzola P. A systematic review of the effectiveness, compliance, and critical factors for implementation of safety checklists in surgery. Annals of surgery. 2012 Dec 1;256(6):925-33.