Introduction. Cephalomedullary nailing (CMN) is commonly used for unstable pertrochanteric fracture. CMN is relatively safe method although various complications can potentially occur needing revision surgery. Commonly used salvage procedures such as renailing, hemiarthroplasty, conservative treatment or total hip arthroplasty (THA) are viable alternatives. The aim was to investigate the rate of THA after CMN and evaluate the performance on conversion total hip arthroplasty (cTHA) after failure of CMN. Method. Collected data included patients from two orthopedic centers. Data consisted of all cTHAs after CMN between 2014-2020 and primary cementless THA operations between 2013-2023. Primary THA operations were treated as a control group where Oxford Hip Score (OHS) was the main compared variable. Result. From 2398 proximal femoral hip procedures 1667 CMN procedures were included. Altogether 46/1667 (2.8%) CMNs later received THA. Indications for THA after CMN failure were 13 (28.3%) cut-outs, nine (19.6%) cut-throughs, eight (17.4%) nail breakages, seven (15.2%) post traumatic arthrosis, seven (15.2%) nonunions, one (2.2%) malunion and one (2.2%) collum screw withdrawal. Mean (SD) time to complication after CMN operation is 5.9 (6.8) months. Mean (SD) time from nail procedure to THA was 10.4 (12.0) months. Total complication rate for cTHA after CMN was 17.4%. Reported complications were infection with seven (15.2%) cases and one (2.2%) nerve damage. Mean (SD) time to cTHA complication was 3.6 (6.1) months. One-sample T-test showed OHS to be significantly better (P<.001) for primary cementless THA compared to cTHA after one year. Conclusion. Altogether 2.8% of CMN were converted to THA. Nearly half (47.8%) of the cTHA procedures were due to CMN cut-out or cut-through. OHS was significantly better in primary cementless THA compared to cTHA. Prosthetic joint infection was the most frequent complication related to cTHA

Introduction. Many patients with obesity experience knee pain. Excess body weight is a modifiable risk factor for osteoarthritis (OA) and weight loss is encouraged in patients with OA. Bariatric surgery could improve or limit the progression of these conditions through significant weight loss. The Oxford Knee Score (OKS) is a validated tool in the assessment of knee replacement surgery for OA. We present a novel application of the OKS to assess knee pain & function after weight loss surgery. The primary aim of this study was to assess whether there was a significant difference in mean OKS before and 24 months after weight loss surgery. Method. Eighteen female participants were included in this study. They underwent sleeve gastrectomy or Roux-en-Y gastric bypass. Patient demographics, body mass index (BMI) and OKS were collected pre- and 24 months post operatively. Result. There was an increase in the mean OKS from 31.8 (SD 11.8) pre surgery to 36.6 (SD 12.3) at 24 months. This was statistically significant (95% CI 0.99-10.5, p=0.02). Mean BMI reduced from 46.6 kg/m. 2. (SD 5.8) to 33.0 kg/m. 2. (SD 3.5). Conclusion. A significant improvement in mean OKS was seen after weight loss surgery. These findings demonstrate an improvement in knee pain & function with weight loss. This study contributes to a larger project evaluating the kinetic and kinematic changes to walking gait from weight loss

Aims. While residual fixed flexion deformity (FFD) in unicompartmental knee arthroplasty (UKA) has been associated with worse functional outcomes, limited evidence exists regarding FFD changes. The objective of this study was to quantify FFD changes in patients with medial unicompartmental knee arthritis undergoing UKA, and investigate any correlation with clinical outcomes. Methods. This study included 136 patients undergoing robotic arm-assisted medial UKA between January 2018 and December 2022. The study included 75 males (55.1%) and 61 (44.9%) females, with a mean age of 67.1 years (45 to 90). Patients were divided into three study groups based on the degree of preoperative FFD: ≤ 5°, 5° to ≤ 10°, and > 10°. Intraoperative optical motion capture technology was used to assess pre- and postoperative FFD. Clinical FFD was measured pre- and postoperatively at six weeks and one year following surgery. Preoperative and one-year postoperative Oxford Knee Scores (OKS) were collected. Results. Overall, the median preoperative navigated (NAV) FFD measured 6.0° (IQR 3.1 to 8), while the median postoperative NAV FFD was 3.0° (IQR 1° to 4.4°), representing a mean correction of 49.2%. The median preoperative clinical FFD was 5° (IQR 0° to 9.75°) for the entire cohort, which decreased to 3.0° (IQR 0° to 5°) and 2° (IQR 0° to 3°) at six weeks and one year postoperatively, respectively. A statistically significant improvement in PROMs compared with baseline was evident in all groups (p < 0.001). Regression analyses showed that participants who experienced a larger FFD correction, showed greater improvement in PROMs (β = 0.609, p = 0.049; 95% CI 0.002 to 1.216). Conclusion. This study found that UKA was associated with an approximately 50% improvement in preoperative FFD across all three examined groups. Participants with greater correction of FFD also demonstrated larger OKS gains. These findings could prove a useful augment to clinical decision-making regarding candidacy for UKA and anticipated improvements in FFD

Aims. In 2015, we published the results of our ceramic-on-metal (CoM) total hip arthroplasties (THAs) performed between October 2007 and July 2009 with a mean follow-up of 34 months (23 to 45) and a revision rate of 3.1%. The aim of this paper is to present the longer-term outcomes. Methods. A total of 264 patients were reviewed at a mean of 5.8 years (4.6 to 7.2) and 10.1 years (9.2 to 10.6) to determine revision rate, pain, outcome scores, radiological analysis, and blood ion levels. Those who were unwilling or unable to travel were contacted by telephone. Results. The all-cause revision rate at six years was 3.1% (eight THAs), increasing to 8.8% (18 THAs) at ten years. Of these, there were four and then seven bearing-related revisions at six and ten years, respectively. There was a statistically significant deterioration in the visual analogue scale pain score and Oxford Hip Score (OHS) between six and ten years. There were 18 CoM THAs in 17 patients who had a cobalt or chromium level over 4 ppb and ten CoM THAs in nine patients who had a cobalt or chromium level higher than 7 ppb with a statistically significant increase in chromium levels only between the two timepoints. Overall, 84 stems (39.1%) had significant radiolucent lines at ten years compared to 65 (25.5%) at six years. Conclusion. When compared to the original review, there has been a significant deterioration in pain score, OHS, radiograph appearance, and, most critically, survival has fallen to 91.2%, which does not meet the Orthopaedic Data Evaluation Panel (ODEP) 10 A* 95% threshold. Although this bearing is no longer on the market, 2.5% were bearing-related revisions, which have relevance to the discussion around modular dual-mobility implants that have a similar metal interface

Aims

Reverse shoulder arthroplasty (RSA) has become the most common type of shoulder arthroplasty used in the UK, and a better understanding of the outcomes after revision of a failed RSA is needed. The aim of this study was to review the current evidence systematically to determine patient-reported outcome measures and the rates of re-revision and complications for patients undergoing revision of a RSA.

Aims. In patients with a failed radial head arthroplasty (RHA), simple removal of the implant is an option. However, there is little information in the literature about the outcome of this procedure. The aim of this study was to review the mid-term clinical and radiological results, and the rate of complications and removal of the implant, in patients whose initial RHA was undertaken acutely for trauma involving the elbow. Methods. A total of 11 patients in whom removal of a RHA without reimplantation was undertaken as a revision procedure were reviewed at a mean follow-up of 8.4 years (6 to 11). The range of motion (ROM) and stability of the elbow were recorded. Pain was assessed using a visual analogue scale (VAS). The functional outcome was assessed using the Mayo Elbow Performance Score (MEPS), the Oxford Elbow Score (OES), and the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH). Radiological examination included the assessment of heterotopic ossification (HO), implant loosening, capitellar erosion, overlengthening, and osteoarthritis. Complications and the rate of further surgery were also recorded. Results. The indications for removal of the implant were stiffness in five patients, aseptic loosening in five, and pain attributed to the RHA in three. The mean time interval between RHA for trauma to removal was ten months (7 to 21). Preoperatively, three patients had overlengthening of the implant, three had capitellar erosion, six had HO, and four had radiological evidence of loosening. At the final follow-up, the mean the flexion-extension arc improved significantly by 38.2° (95% CI 20 to 59; p = 0.002) and the mean arc of prono-supination improved significantly by 20° (95% CI 0 to 72.5; p = 0.035). The mean pain VAS score improved significantly by 3.5 (95% CI 2 to 5.5; p = 0.004). The mean MEPS improved significantly by 27.5 (95% CI 17.5 to 42.5; p = 0.002). The mean OES improved significantly by 9 (95% CI 2.5 to 14; p = 0.012), and the mean DASH score improved significantly by 23.5 (95% CI 7.5 to 31.6; p = 0.012). Ten patients (91%) had HO and osteoarthritis. Two patients underwent further surgery due to stiffness and pain, respectively. Conclusion. Simple removal of the implant at revision surgery following a failed RHA introduced following trauma provides satisfactory mid-term results with an acceptable risk of complications. Osteoarthritis, instability, and radioulnar impingement were not problems in this series. Cite this article: Bone Joint J 2024;106-B(11):1327–1332

Aims

The aim of this study was to determine whether obesity had a detrimental effect on the long-term performance and survival of medial unicompartmental knee arthroplasties (UKAs).

Aims. The aims were to assess whether joint-specific outcome after total knee arthroplasty (TKA) was influenced by implant design over a 12-year follow-up period, and whether patient-related factors were associated with loss to follow-up and mortality risk. Methods. Long-term follow-up of a randomized controlled trial was undertaken. A total of 212 patients were allocated a Triathlon or a Kinemax TKA. Patients were assessed preoperatively, and one, three, eight, and 12 years postoperatively using the Oxford Knee Score (OKS). Reasons for patient lost to follow-up, mortality, and revision were recorded. Results. A total of 94 patients completed 12-year functional follow-up (62 females, mean age 66 years (43 to 82) at index surgery). There was a clinically significantly greater improvement in the OKS at one year (mean difference (MD) 3.0 (95% CI 0.4 to 5.7); p = 0.027) and three years (MD 4.7 (95% CI 1.9 to 7.5); p = 0.001) for the Triathlon group, but no differences were observed at eight (p = 0.331) or 12 years’ (p = 0.181) follow-up. When assessing the OKS in the patients surviving to 12 years, the Triathlon group had a clinically significantly greater improvement in the OKS (marginal mean 3.8 (95% CI 0.2 to 7.4); p = 0.040). Loss to functional follow-up (53%, n = 109/204) was independently associated with older age (p = 0.001). Patient mortality was the major reason (56.4%, n = 62/110) for loss to follow-up. Older age (p < 0.001) and worse preoperative OKS (p = 0.043) were independently associated with increased mortality risk. An age at time of surgery of ≥ 72 years was 75% sensitive and 74% specific for predicting mortality with an area under the curve of 78.1% (95% CI 70.9 to 85.3; p < 0.001). Conclusion. The Triathlon TKA was associated with clinically meaningful greater improvement in knee-specific outcome when compared to the Kinemax TKA. Loss to follow-up at 12 years was a limitation, and studies planning longer-term functional assessment could limit their cohort to patients aged under 72 years. Cite this article: Bone Jt Open 2024;5(10):911–919

Aims. The aim of this study was to evaluate the suitability of the tapered cone stem in total hip arthroplasty (THA) in patients with excessive femoral anteversion and after femoral osteotomy. Methods. We included patients who underwent THA using Wagner Cone due to proximal femur anatomical abnormalities between August 2014 and January 2019 at a single institution. We investigated implant survival time using the endpoint of dislocation and revision, and compared the prevalence of prosthetic impingements between the Wagner Cone, a tapered cone stem, and the Taperloc, a tapered wedge stem, through simulation. We also collected Oxford Hip Score (OHS), visual analogue scale (VAS) satisfaction, and VAS pain by postal survey in August 2023 and explored variables associated with those scores. Results. Of the 58 patients (62 hips), two (two hips) presented with dislocation or reoperation, and Kaplan-Meier analysis indicated a five-year survival rate of 96.7% (95% CI 92.4 to 100). Mean stem anteversion was 35.2° (SD 18.2°) for the Taperloc stem and 29.8° (SD 7.9°) for the Wagner Cone stem; mean reduction from Taperloc to Wagner Cone was 5.4° (SD 18.8°). Overall, 55 hips (52 patients) were simulated, and the prevalence of prosthetic impingement was lower for the Wagner Cone (5.5%, 3/55) compared with the Taperloc (20.0%, 11/55) stem, with an odds ratio of 0.20 (p = 0.038). Among the 33 respondents to the postal survey (36 hips), the mean scores were VAS pain 10.9, VAS satisfaction 86.9, and OHS 44.7. A multivariable analysis revealed that reduction of stem anteversion from Taperloc to Wagner Cone was more favourable for VAS pain (p = 0.029) and VAS satisfaction (p = 0.002). Conclusion. The mid-term survival rate for THA using the Wagner Cone stem was high, which may be supported by a reduction in prosthetic impingement. The reduction in excessive stem anteversion by using a tapered cone stem was associated with reduced pain and increased patient satisfaction. Cite this article: Bone Jt Open 2024;5(10):858–867

The aim of this study was to evaluate the long-term outcomes of patients who had sustained an unstable ankle fracture with a posterior malleolus fracture (PMF) and without (N-PMF). Adult patients presenting to a single academic trauma centre in Edinburgh, UK, between 2009 and 2012 with an unstable ankle fracture requiring surgery were identified. The primary outcome measure was the Olerud Molander Ankle Score (OMAS). Secondary measures included Euroqol-5D-3L Index (Eq5D3L), Euroqol-5D-VAS and Manchester Oxford Foot Questionnaire (MOXFQ). There were 304 patients in the study cohort. The mean age was 49.6 years (16.3–78.3) and 33% (n=100) male and 67% (n=204) female. Of these, 67% (n=204) had a PMF and 33% did not (n=100). No patient received a computed tomography (CT) scan pre-operatively. Only 10% of PMFs (22/204) were managed with internal fixation. At a mean of 13.8 years (11.3 – 15.3) the median OMAS score was 85 (Interquartile Range 60 – 100). There was no difference in OMAS between the N-PMF and PMF groups (85 [56.25 – 100] vs 85 [61.25 – 100]; p = 0.580). There was also no difference for MOXFQ (N-PMF 7 [0 – 36.75] vs PMF 8 [0–38.75]; p = 0.643), the EQ5D Index (N-PMF 0.8 [0.7 – 1] vs PMF 0.8 [0.7 – 1]; p = 0.720) and EQ5D VAS (N-PMF 80 [70 – 90] vs PMF 80 [60 – 90]; p = 0.224). The presence of a PMF does not affect the long-term patient reported outcomes in patients with a surgically managed unstable ankle fracture

Restoration of native Coronal Plane Alignment of the Knee (CPAK) phenotype is a strategy suggested to achieve better satisfaction. The aim of this study was to investigate the influence of changes in CPAK classification on patient-reported outcome measures (PROMs) and survivorship in a large cohort of manual mechanically aligned (MA) cemented TKAs. A retrospective analysis of 1062 consecutive cemented TKAs using MA philosophy at a single institution. Pre- and post-operative hip-knee-ankle radiographs were classified using the CPAK classification. Oxford Knee Score (OKS) and patient satisfaction (4-point-Likert scale) were collected prospectively. Implant survival data was obtained from our national arthroplasty database. We compared the outcomes of patients who maintained or changed their CPAK classification following TKA. Satisfaction was analysed using chi-square test, and OKS was analysed using Mann-Whitney test. Pre-operatively, most patients were CPAK type-I (38.8%). 85.5% of patients changed their CPAK type post-operatively, with CPAK type-V observed in 41.2% of these. Significantly better satisfaction (p=0.033) and OKS (p=0.021) were observed at one-year follow-up in patients who changed CPAK type, although the difference was below OKS minimally important clinical difference. There was no difference in satisfaction (p=0.73) and OKS (p=0.26) at one year between CPAK-V and non-V classifications. Post-operative CPAK type had no correlation with satisfaction and OKS. 12 TKAs (1.1%) were revised within 10 years (3 septic). In this large cohort of MA-TKA, excellent survivorship was observed at 10 years, with no demonstrable difference in outcome related to the final CPAK phenotype or change in phenotype

Aims. To determine whether obesity and malnutrition have a synergistic effect on outcomes from skeletal trauma or elective orthopaedic surgery. Methods. Electronic databases including MEDLINE, Global Health, Embase, Web of Science, ScienceDirect, and PEDRo were searched up to 14 April 2024, as well as conference proceedings and the reference lists of included studies. Studies were appraised using tools according to study design, including the Oxford Levels of Evidence, the Institute of Health Economics case series quality appraisal checklist, and the CLARITY checklist for cohort studies. Studies were eligible if they reported the effects of combined malnutrition and obesity on outcomes from skeletal trauma or elective orthopaedic surgery. Results. A total of eight studies (106,319 patients) were included. These carried moderate to high risk of bias. Combined obesity and malnutrition did not lead to worse outcomes in patients undergoing total shoulder arthroplasty or repair of proximal humeral fractures (two retrospective cohort studies). Three studies (two retrospective cohort studies, one case series) found that malnourishment and obesity had a synergistic effect and led to poor outcomes in total hip or knee arthroplasty, including longer length of stay and higher complication rates. One retrospective cohort study pertaining to posterior lumbar fusion found that malnourished obese patients had higher odds of developing surgical site infection and sepsis, as well as higher odds of requiring a revision procedure. Conclusion. Combined malnutrition and obesity have a synergistic effect and lead to poor outcomes in lower limb procedures. Appropriate preoperative optimization and postoperative care are required to improve outcomes in this group of patients. Cite this article: Bone Joint J 2024;106-B(10):1044–1049

Aims. The aim of this study was to evaluate the outcome of complex radial head fractures at mid-term follow-up, and determine whether open reduction and internal fixation (ORIF) or radial head arthroplasty (RHA) should be recommended for surgical treatment. Methods. Patients who underwent surgery for complex radial head fractures (Mason type III, ≥ three fragments) were divided into two groups (ORIF and RHA) and propensity score matching was used to individually match patients based on patient characteristics. Ultimately, 84 patients were included in this study. After a mean follow-up of 4.1 years (2.0 to 9.5), patients were invited for clinical and radiological assessment. The Mayo Elbow Performance Score (MEPS), Oxford Elbow Score (OES), and Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire score were evaluated. Results. Patients treated with ORIF showed significantly better postoperative range of motion for flexion and extension (121.1° (SD 16.4°) vs 108.1° (SD 25.8°); p = 0.018). Postoperative functional scores also showed significantly better results in the ORIF group (MEPS 90.1 (SD 13.6) vs 78 (SD 20.5); p = 0.004). There was no significant difference between the groups in terms of the complication rate (RHA 23.8% (n = 10) vs ORIF 26.2% (n = 11)). Implant-related complications occurred in six cases (14.3%) in the RHA group and in five cases (11.9%) in the ORIF group. Conclusion. Irrespective of the patient’s age, sex, type of injury, or number of fracture fragments, ORIF of the radial head should be attempted initially, if a stable reconstruction can be achieved, as it seems to provide a superior postoperative outcome for the patient compared to primary RHA. If reconstruction is not feasible, RHA is still a viable alternative. In the surgical treatment of complex radial head fractures, reconstruction shows superior postoperative outcomes compared to RHA. Good postoperative results can be achieved even after failed reconstruction and conversion to secondary RHA. Therefore, we encourage surgeons to favour reconstruction of complex radial head fractures, regardless of injury type or number of fragments, as long as a stable fixation can be achieved. Cite this article: Bone Joint J 2024;106-B(10):1158–1164

The October 2024 Research Roundup³⁶⁰ looks at: Fracture risk among stroke survivors according to post-stroke disability status and stroke type; Noise-induced hearing loss: should surgeons be wearing ear protection during primary total joint replacement?; Intravenous dexamethasone in hip arthroscopy can enhance recovery; Patient-reported outcomes following periprosthetic joint infection of the hip and knee: a longitudinal, prospective observational study; When should surgery take place after weight loss?; Which type of surgery is the hardest physically and mentally?

Aims

The aims of this study were to validate the minimal clinically important difference (MCID) and patient-acceptable symptom state (PASS) thresholds for Western Ontario Shoulder Instability Index (WOSI), Rowe score, American Shoulder and Elbow Surgeons (ASES), and visual analogue scale (VAS) scores following arthroscopic Bankart repair, and to identify preoperative threshold values of these scores that could predict the achievement of MCID and PASS.

The October 2024 Hip & Pelvis Roundup³⁶⁰ looks at: Does the primary surgical approach matter when choosing the approach for revision total hip arthroplasty?; Time to achieve the minimal clinically important difference in primary total hip arthroplasty: comparison of anterior and posterior surgical approaches; To scope or not to scope: arthroscopy as an adjunct to PAO does not provide better clinical outcomes at one year than PAO alone; Re-exploring horizons in hip resurfacing: two-year results of a ceramic-on-ceramic hip resurfacing; Association between tranexamic acid and decreased periprosthetic joint infection risk in patients undergoing total hip and knee arthroplasty; Octogenarians fare well: in revision for infection age is not a bar.

Aims. The influence of metabolic syndrome (MetS) on the outcome after hip and knee arthroplasty is debated. We aimed to investigate the change in patient-reported outcome measure (PROM) scores after hip and knee arthroplasty, comparing patients with and without MetS. Methods. From 1 May 2017 to 30 November 2019, a prospective cohort of 2,586 patients undergoing elective unilateral hip and knee arthroplasty was established in Denmark. Data from national registries and a local database were used to determine the presence of MetS. Patients’ scores on Oxford Hip Score (OHS) or Oxford Knee Score (OKS), EuroQol five-dimension five-level questionnaire (EQ-5D-5L), University of California, Los Angeles (UCLA) Activity Scale, and Forgotten Joint Score (FJS) at baseline, three, 12, and 24 months after surgery were collected. Primary outcome was the difference between groups from baseline to 12 months in OHS and OKS. Secondary outcomes were scores of OHS and OKS at three and 24 months and EQ-5D-5L, UCLA Activity Scale, and FJS at three, 12, and 24 months after surgery. Generalized linear mixed model was applied, adjusting for age, sex, Charlson Comorbidity Index, and smoking to present marginal mean and associated 95% CIs. Results. A total of 62.3% (1,611/2,586) of the cohort met the criteria for MetS. Both groups showed similar increase in mean OHS (MetS group 22.5 (95% CI 21.8 to 23.1), non-MetS group 22.1 (21.3 to 22.8); p = 0.477) and mean OKS (MetS group 18.0 (17.4 to 18.6), non-MetS group 17.8 (17.0 to 18.7); p = 0.722) at 12 months' follow-up. Between groups, similar improvements were seen for OHS and OKS at three and 24 months postoperatively and for the mean EQ-5D-5L, EuroQol-visual analogue scale (EQ-VAS), UCLA Activity Scale, and FJS at every timepoint. Conclusion. Patients meeting the criteria for MetS obtain the same improvement in PROM scores as individuals without MetS up to 24 months after hip and knee arthroplasty. This is important for the clinician to take into account when assessing and advising patients with MetS. Cite this article: Bone Joint J 2024;106-B(10):1074–1083

Aims. To explore key stakeholder views around feasibility and acceptability of trials seeking to prevent post-traumatic osteoarthritis (PTOA) following knee injury, and provide guidance for next steps in PTOA trial design. Methods. Healthcare professionals, clinicians, and/or researchers (HCP/Rs) were surveyed, and the data were presented at a congress workshop. A second and related survey was then developed for people with joint damage caused by knee injury and/or osteoarthritis (PJDs), who were approached by a UK Charity newsletter or Oxford involvement registry. Anonymized data were collected and analyzed in Qualtrics. Results. Survey responses (n = 19 HCP/Rs, 39 PJDs) supported studies testing pharmacological agents preventing PTOA. All HCP/Rs and 30/31 (97%) PJDs supported the development of new treatments that improved or delayed knee symptoms and damage to knee structure. PJDs thought that improving structural knee damage was more important than knee symptoms. Both groups found studies more acceptable as expected future benefit and risk of PTOA increased. All drug delivery routes were acceptable. Workshop participants (around n = 60) reflected survey views. Discussions suggested that stratifying using molecular testing for likely drug response appeared to be more acceptable than using characteristics such as sex, age, and BMI. Conclusion. Our findings supported PTOA drug intervention studies, including situations where there is low risk of disease, no expected benefit of treatment, and frequent treatment administration. PJDs appeared less risk-averse than HCP/Rs. This work reinforces the benefits of consensus and involvement work in the co-creation of PTOA drug trial design. Involvement of key stakeholders, such as PJDs with different risks of OA and regulatory representatives, are critical for trial design success. Cite this article: Bone Joint Res 2024;13(9):513–524

Aims. Steroid injections are used for subacromial pain syndrome and can be administered via the anterolateral or posterior approach to the subacromial space. It is not currently known which approach is superior in terms of improving clinical symptoms and function. This is the protocol for a randomized controlled trial (RCT) to compare the clinical effectiveness of a steroid injection given via the anterolateral or the posterior approach to the subacromial space. Methods. The Subacromial Approach Injection Trial (SAInT) study is a single-centre, parallel, two-arm RCT. Participants will be allocated on a 1:1 basis to a subacromial steroid injection via either the anterolateral or the posterior approach to the subacromial space. Participants in both trial arms will then receive physiotherapy as standard of care for subacromial pain syndrome. The primary analysis will compare the change in Oxford Shoulder Score (OSS) at three months after injection. Secondary outcomes include the change in OSS at six and 12 months, as well as the Pain Numeric Rating Scale (0 = no pain, 10 = worst pain), Disabilities of Arm, Shoulder and Hand questionnaire (DASH), and 36-Item Short-Form Health Survey (SF-36) (RAND) at three months, six months, and one year after injection. Assessment of pain experienced during the injection will also be determined. A minimum of 86 patients will be recruited to obtain an 80% power to detect a minimally important difference of six points on the OSS change between the groups at three months after injection. Conclusion. The results of this trial will demonstrate if there is a difference in shoulder pain and function after a subacromial space steroid injection between the anterolateral versus posterior approach in patients with subacromial pain syndrome. This will help to guide treatment for patients with subacromial pain syndrome. Cite this article: Bone Jt Open 2024;5(9):729–735