Femoroacetabular impingement is recognised as being a cause of labral tears and chondral damage. We report a series of five patients who presented with persistent pain in the hip after arthroscopy for isolated labral debridement. All five had a bony abnormality consistent with cam-type femoroacetabular impingement. They had a further operation to correct the abnormality by chondro-osteoplasty of the femoral head-neck junction. At a mean follow-up of 16.3 months (12 to 24) all had symptomatic improvement.

We report a review of 33 hips (32 patients) which had required repeat open reduction for congenital dislocation of the hip. They were followed up for a mean of 76 months (36 to 132). Factors predisposing to failure of the initial open reduction were simultaneous femoral or pelvic osteotomy, inadequate inferior capsular release, and inadequate capsulorrhaphy. Avascular necrosis had developed in more than half the hips, usually before the final open reduction. At review, 11 of the hips (one-third) were in Severin grade 3 or worse; five had significant symptoms and only ten were asymptomatic and radiographically normal. Once redisplacement has occurred after primary open reduction, attempts to reduce the head by closed means or by pelvic or femoral osteotomy are usually unsuccessful and a further open reduction is necessary.

Thirteen total hip replacements with titanium alloy femoral components required revision for loosening at an average of two years after implantation. At revision the soft tissues around the implant were darkly stained and a proliferative membrane had invaded the cement-bone interface. The femoral components showed polishing of parts of their shot-blasted surfaces. Histology showed a fibroblastic reaction with abundant titanium lying free and within histiocytes, and a scanty foreign-body giant-cell reaction. Surface analysis of the removed femoral components and chemical analysis of the excised tissues is described. Tissue reaction in response to the metal-wear debris may have contributed to the early failure of these implants.

Eleven patients underwent disarticulation for infected arthroplasty of the hip. Exchange total hip arthroplasty or conversion to a Girdlestone excision arthroplasty had been undertaken previously an average of 2.9 times. The indications for disarticulation were as a life-saving measure, or as a result of severe infection of soft tissue and bone, loss of bone stock, or vascular injury. While the indications for this drastic operation were highly individual, there were instances where disarticulation could have been avoided if repeated exchange operations had been eschewed in deference to a Girdlestone procedure.

We describe three prostheses with cemented titanium-alloy stems and Al₂O₃ ceramic femoral heads which had to be revised after a mean period of implantation of 78 months. In each case, the neck of the prosthesis had been so severely worn that the profile was elliptical rather than circular. There was severe metallosis of the periprosthetic tissues. Metal particles isolated from the tissues were approximately one nanometre in size and the ratios of titanium, aluminium and vanadium in the particles were the same as in the original alloy. Histologically, the high concentration of metal particles masked the presence of high-density polyethylene (HDP) debris, but again particles about one nanometre in size were isolated from the tissues. The severe necrobiosis and necrosis noted were consistent with other reports of the presence of extensive wear particles in periprosthetic tissues. Wear is presumed to have occurred as a result of mismatch between the shape or size of the taper cone and the femoral head, or to changes in the geometry of loading due to migration of the cup. To facilitate early intervention, patients with this design of prosthesis should be monitored radiologically.

The early failure and revision of bimodular primary total hip arthroplasty prostheses requires the identification of the risk factors for material loss and wear at the taper junctions through taper wear analysis. Deviations in taper geometries between revised and pristine modular neck tapers were determined using high resolution tactile measurements. A new algorithm was developed and validated to allow the quantitative analysis of material loss, complementing the standard visual inspection currently used.

The algorithm was applied to a sample of 27 retrievals (in situ from 2.9 to 38.1 months) of the withdrawn Rejuvenate modular prosthesis. The mean wear volumes on the flat distal neck piece taper was 3.35 mm³ (0.55 to 7.57), mainly occurring in a characteristic pattern in areas with high mechanical loading. Wear volume tended to increase with time to revision (r² = 0.423, p = 0.001). Implant and patient specific data (offset, stem size, patient’s mass, age and body mass index) did not correlate with the amount of material loss observed (p >  0.078). Bilaterally revised implants showed higher amounts of combined total material loss and similar wear patterns on both sides. The consistent wear pattern found in this study has not been reported previously, suggesting that the device design and materials are associated with the failure of this prosthesis.

Cite this article: Bone Joint J 2015;97-B:1350–7.

Aims. The volume of ambulatory total hip arthroplasty (THA) procedures is increasing due to the emphasis on value-based care. The purpose of the study is to identify the causes for failed same-day discharge (SDD) and perioperative factors leading to failed SDD. Methods. This retrospective cohort study followed pre-selected patients for SDD THA from 1 August 2018 to 31 December 2020. Inclusion criteria were patients undergoing unilateral THA with appropriate social support, age 18 to 75 years, and BMI < 37 kg/m. 2. Patients with opioid dependence, coronary artery disease, and valvular heart disease were excluded. Demographics, comorbidities, and perioperative data were collected from the electronic medical records. Possible risk factors for failed SDD were identified using multivariate logistic regression. Results. In all, 278 patients were identified with a mean age of 57.1 years (SD 8.1) and a mean BMI of 27.3 kg/m. 2. (SD 4.5). A total of 96 patients failed SDD, with the most common reasons being failure to clear physical therapy (26%), dizziness (22%), and postoperative nausea and vomiting (11%). Risk factors associated with failed SDD included smokers (odds ratio (OR) 6.24; p = 0.009), a maximum postoperative pain score > 8 (OR 4.76; p = 0.004), and procedures starting after 11 am (OR 2.28; p = 0.015). A higher postoperative tolerable pain goal (numerical rating scale 4 to 10) was found to be associated with successful SDD (OR 2.7; p = 0.001). Age, BMI, surgical approach, American Society of Anesthesiologists grade, and anaesthesia type were not associated with failed SDD. Conclusion. SDD is a safe and viable option for pre-selected patients interested in rapid recovery THA. The most common causes for failure to launch were failing to clear physical thereapy and patient symptomatology. Risk factors associated with failed SSD highlight the importance of preoperative counselling regarding smoking cessation and postoperative pain to set reasonable expectations. Future interventions should aim to improve patient postoperative mobilization, pain control, and decrease symptomatology. Cite this article: Bone Jt Open 2022;3(9):684–691

Aims. When performing revision total hip arthroplasty using diaphyseal-engaging titanium tapered stems (TTS), the recommended 3 to 4 cm of stem-cortical diaphyseal contact may not be available. In challenging cases such as these with only 2 cm of contact, can sufficient axial stability be achieved and what is the benefit of a prophylactic cable? This study sought to determine, first, whether a prophylactic cable allows for sufficient axial stability when the contact length is 2 cm, and second, if differing TTS taper angles (2° vs 3.5°) impact these results. Methods. A biomechanical matched-pair cadaveric study was designed using six matched pairs of human fresh cadaveric femora prepared so that 2 cm of diaphyseal bone engaged with 2° (right femora) or 3.5° (left femora) TTS. Before impaction, three matched pairs received a single 100 lb-tensioned prophylactic beaded cable; the remaining three matched pairs received no cable adjuncts. Specimens underwent stepwise axial loading to 2600 N or until failure, defined as stem subsidence > 5 mm. Results. All specimens without cable adjuncts (6/6 femora) failed during axial testing, while all specimens with a prophylactic cable (6/6) successfully resisted axial load, regardless of taper angle. In total, four of the failed specimens experienced proximal longitudinal fractures, three of which occurred with the higher 3.5° TTS. One fracture occurred in a 3.5° TTS with a prophylactic cable yet passed axial testing, subsiding < 5 mm. Among specimens with a prophylactic cable, the 3.5° TTS resulted in lower mean subsidence (0.5 mm (SD 0.8)) compared with the 2° TTS (2.4 mm (SD 1.8)). Conclusion. A single prophylactic beaded cable dramatically improved initial axial stability when stem-cortex contact length was 2 cm. All implants failed secondary to fracture or subsidence > 5 mm when a prophylactic cable was not used. A higher taper angle appears to decrease the magnitude of subsidence but increased the fracture risk. The fracture risk was mitigated by the use of a prophylactic cable. Cite this article: Bone Jt Open 2023;4(7):472–477

Tennis elbow (lateral epicondylitis or lateral elbow tendinopathy) is a self-limiting condition in most patients. Surgery is often offered to patients who fail to improve with conservative treatment. However, there is no evidence to support the superiority of surgery over continued nonoperative care or no treatment. New evidence also suggests that the prognosis of tennis elbow is not influenced by the duration of symptoms, and that there is a 50% probability of recovery every three to four months. This finding challenges the belief that failed nonoperative care is an indication for surgery. In this annotation, we discuss the clinical and research implications of the benign clinical course of tennis elbow. Cite this article: Bone Joint J 2023;105-B(2):109–111

Aims. The number of revision total ankle arthroplasties (TAAs) which are undertaken is increasing. Few studies have reported the survival after this procedure. The primary aim of this study was to analyze the survival of revision ankle arthroplasties using large datasets. Secondary aims were to summarize the demographics of the patients, the indications for revision TAA, further operations, and predictors of survival. Methods. The study combined data from the National Joint Registry and NHS Digital to report the survival of revision TAA. We have previously reported the failure rates and risk factors for failure after TAA, and the outcome of fusion after a failed TAA, using the same methodology. Survival was assessed using life tables and Kaplan Meier graphs. Cox proportional hazards regression models were fitted to compare failure rates. Results. A total of 228 patients underwent revision TAA. The mean follow-up was 2.6 years (SD 2.0). The mean time between the initial procedure and revision was 2.3 years (SD 1.8). The most commonly used implant was the Inbone which was used in 81 patients. A total of 29 (12.7%) failed; nine (3.9%) patients underwent a further revision, 19 (8.3%) underwent a fusion, and one (0.4%) had an amputation. The rate of survival was 95.4% (95% confidence interval (CI) 91.6 to 97.5) at one year, 87.7% (95% CI 81.9 to 91.7; n = 124) at three years and 77.5% (95% CI 66.9 to 85.0; n = 57) at five years. Revision-specific implants had a better survival than when primary implants were used at revision. A total of 50 patients (21.9%) had further surgery; 19 (8.3%) underwent reoperation in the first 12 months. Cox regression models were prepared. In crude analysis the only significant risk factors for failure were the use of cement (hazard ratio (HR) 3.02 (95% CI 1.13 to 8.09)) and the time since the primary procedure (HR 0.67 (95% CI 0.47 to 0.97)). No risk factors for failure were identified in multivariable Cox regression modelling. Conclusion. Revision TAAs have good medium term survival and low rates of further surgery. New modular revision implants appear to have improved the survival compared with the use of traditional primary implants at revision. Cite this article: Bone Joint J 2023;105-B(11):1184–1188

Aims. The best surgical strategy for the management of displaced bucket-handle (BH) meniscal tears in an anterior cruciate ligament (ACL)-deficient knee is unclear. Combining meniscal repair with ACL reconstruction (ACLR) is thought to improve meniscal healing rates; however, patients with displaced BH meniscal tears may lack extension. This leads some to advocate staged surgery to avoid postoperative stiffness and loss of range of motion (ROM) following ACLR. Methods. We reviewed the data for a consecutive series of 88 patients (mean age 27.1 years (15 to 49); 65 male (74%) and 23 female (26%)) who underwent single-stage repair of a displaced BH meniscal tear (67 medial (76%) and 21 lateral (24%)) with concomitant hamstring autograft ACLR. The patient-reported outcome measures (PROMs) EuroQol visual analogue scale (EQ-VAS), EuroQol five-dimension health questionnaire (EQ-5D), Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee score (IKDC), and Tegner score were recorded at final follow-up. A Kaplan-Meier survival analysis was performed to estimate meniscal repair survivorship. Analyses were performed with different cut-offs for meniscal and ACL injury-to-surgery time (within three weeks, three to ten weeks, and more than ten weeks). Results. Meniscal repair survivorship at a median final follow-up of 55 months (interquartile range (IQR) 24 to 91) was 82% (95% confidence interval 70 to 89). A total of 13 meniscus repairs failed (12 requiring meniscectomy and one requiring a further meniscal repair). At final follow-up, median PROMs were: EQ-VAS 85 (IQR 75 to 90), EQ-5D Index 0.84 (IQR 0.74 to 1.00), KOOS Pain 89 (IQR 80 to 94), KOOS Symptoms 82 (IQR 71 to 93), KOOS Activities of Daily Living 97 (IQR 91 to 100), KOOS Sport and Recreation 80 (IQR 65 to 90), KOOS Quality of Life 69 (IQR 53 to 86), IKDC 82.8 (IQR 67.8 to 90.8), and Tegner 6 (IQR 4 to 7). Two patients underwent revision ACLR following further injuries. One patient had an arthroscopic washout for infection at 11 days post-BH meniscal repair/ACLR. Four patients (4.5%) required a further procedure for stiffness, reduced ROM, and pain, and all were operated on within three weeks of meniscal injury. There was no difference in the interval between meniscal injury and surgery between repairs that failed and those that survived. Conclusion. These data suggest that concomitant ACLR with repair of displaced BH meniscal tears, even if they have been displaced for some time, appears to afford satisfactory PROMs and good survivorship. Repairs within three weeks of meniscal injury may be associated with higher rates of postoperative reintervention for stiffness. Cite this article: Bone Joint J 2022;104-B(6):680–686

Aims. After failed acetabular fractures, total hip arthroplasty (THA) is a challenging procedure and considered the gold standard treatment. The complexity of the procedure depends on the fracture pattern and the initial fracture management. This study’s primary aim was to evaluate patient-reported outcome measures (PROMs) for patients who underwent delayed uncemented acetabular THA after acetabular fractures. The secondary aims were to assess the radiological outcome and the incidence of the associated complications in those patients. Methods. A total of 40 patients underwent cementless acetabular THA following failed treatment of acetabular fractures. The postoperative clinical and radiological outcomes were evaluated for all the cohort. Results. The median (interquartile range (IQR)) Oxford Hip Score (OHS) improved significantly from 9.5 (7 to 11.5), (95% confidence interval (CI) (8 to 10.6)) to 40 (39 to 44), (95% CI (40 to 43)) postoperatively at the latest follow-up (p < 0.001). It was worth noting that the initial acetabular fracture type (simple vs complex), previous acetabular treatment (ORIF vs conservative), fracture union, and restoration of anatomical centre of rotation (COR) did not affect the final OHS. The reconstructed centre of rotation (COR) was restored in 29 (72.5%) patients. The mean abduction angle in whom acetabular fractures were managed conservatively was statistically significantly higher than the surgically treated patients 42.6° (SD 7.4) vs 38° (SD 5.6)) (p = 0.032). We did not have any case of acetabular or femoral loosening at the time of the last follow-up. We had two patients with successful two-stage revision for infection with overall eight-year survival rate was 95.2% (95% CI 86.6% to 100%) with revision for any reason at a median (IQR) duration of follow-up 50 months (16 to 87) months following THA. Conclusion. Delayed cementless acetabular THA in patients with previous failed acetabular fracture treatments produces good clinical outcomes (PROMS) with excellent survivorship, despite the technically demanding nature of the procedure. The initial fracture treatment does not influence the outcome of delayed THA. In selected cases of acetabular fractures (either nondisplaced or with secondary congruency), the initial nonoperative treatment neither resulted in large acetabular defects nor required additional acetabular reconstruction at the time of THA. Cite this article: Bone Jt Open 2021;2(12):1067–1074

The February 2024 Foot & Ankle Roundup. 360. looks at: Survival of revision ankle arthroplasty; Tibiotalocalcaneal nail for the management of open ankle fractures in the elderly patient; Accuracy of a patient-specific total ankle arthroplasty instrumentation; Fusion after failed primary ankle arthroplasty: can it work?; Treatment options for osteochondral lesions of the talus; Managing hair tourniquet syndrome of toe: a rare emergency; Ultrasound-guided collagenase therapy for recurrent plantar fibromatosis: a promising line of therapy?

Aims. One-stage exchange for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) is gaining popularity. The outcome for a repeat one-stage revision THA after a failed one-stage exchange for infection remains unknown. The aim of this study was to report the infection-free and all-cause revision-free survival of repeat one-stage exchange, and to investigate the association between the Musculoskeletal Infection Society (MSIS) staging system and further infection-related failure. Methods. We retrospectively reviewed all repeat one-stage revision THAs performed after failed one-stage exchange THA for infection between January 2008 and December 2016. The final cohort included 32 patients. The mean follow-up after repeat one-stage exchange was 5.3 years (1.2 to 13.0). The patients with a further infection-related failure and/or all-cause revision were reported, and Kaplan-Meier survival for these endpoints determined. Patients were categorized according to the MSIS system, and its association with further infection was analyzed. Results. A total of eight repeat septic revisions (25%) developed a further infection-related failure, and the five-year infection-free survival was 81% (95% confidence interval (CI) 57 to 92). Nine (28%) underwent a further all-cause revision and the five-year all-cause revision-free survival was 74% (95% CI 52 to 88). Neither the MSIS classification of the host status (p = 0.423) nor the limb status (p = 0.366) was significantly associated with further infection-related failure. Conclusion. Repeat one-stage exchange for PJI in THA is associated with a favourable five-year infection-free and all-cause revision-free survival. Notably, the rate of infection control is encouraging when compared with the reported rates after repeat two-stage exchange. The results can be used to counsel patients and help clinicians make informed decisions about treatment. With the available number of patients, further infection-related failure was not associated with the MSIS host or limb status. Cite this article: Bone Joint J 2022;104-B(1):27–33

Aims. Several artificial bone grafts have been developed but fail to achieve anticipated osteogenesis due to their insufficient neovascularization capacity and periosteum support. This study aimed to develop a vascularized bone-periosteum construct (VBPC) to provide better angiogenesis and osteogenesis for bone regeneration. Methods. A total of 24 male New Zealand white rabbits were divided into four groups according to the experimental materials. Allogenic adipose-derived mesenchymal stem cells (AMSCs) were cultured and seeded evenly in the collagen/chitosan sheet to form cell sheet as periosteum. Simultaneously, allogenic AMSCs were seeded onto alginate beads and were cultured to differentiate to endothelial-like cells to form vascularized bone construct (VBC). The cell sheet was wrapped onto VBC to create a vascularized bone-periosteum construct (VBPC). Four different experimental materials – acellular construct, VBC, non-vascularized bone-periosteum construct, and VBPC – were then implanted in bilateral L4-L5 intertransverse space. At 12 weeks post-surgery, the bone-forming capacities were determined by CT, biomechanical testing, histology, and immunohistochemistry staining analyses. Results. At 12 weeks, the VBPC group significantly increased new bone formation volume compared with the other groups. Biomechanical testing demonstrated higher torque strength in the VBPC group. Notably, the haematoxylin and eosin, Masson’s trichrome, and immunohistochemistry-stained histological results revealed that VBPC promoted neovascularization and new bone formation in the spine fusion areas. Conclusion. The tissue-engineered VBPC showed great capability in promoting angiogenesis and osteogenesis in vivo. It may provide a novel approach to create a superior blood supply and nutritional environment to overcome the deficits of current artificial bone graft substitutes. Cite this article: Bone Joint Res 2023;12(12):722–733

Aims. Implant failure has become more common as the number of primary total ankle arthroplasties (TAAs) performed has increased. Although revision arthroplasty has gained attention for functional preservation, the long-term results remain unclear. This study aimed to assess the long-term outcomes of revision TAA using a mobile-bearing prosthesis in a considerably large cohort; the risk factors for failure were also determined. Methods. This single-centre retrospective cohort study included 116 patients (117 ankles) who underwent revision TAA for failed primary TAA between July 2000 and March 2010. Survival analysis and risk factor assessment were performed, and clinical performance and patient satisfaction were evaluated preoperatively and at last follow-up. Results. The mean duration from initial revision TAA to last follow-up was 15.0 years (SD 3.0; 11.2 to 20.5). The cumulative survival rates of the revised ankles were 81% (95% confidence interval (CI) 74% to 88%), 74% (65% to 82%), and 70% (61% to 79%) at five, ten, and 15 years, respectively. Comorbidities prior to primary TAA, aseptic loosening, instability, or grafting of cysts were found to be the most common risk factors for secondary revision. The median value for preoperative pain, as assessed using the visual analogue scale, declined from 6 (interquartile range (IQR) 5 to 8) to 2 (IQR 0 to 5) (p < 0.001) and the mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score improved from 43 (SD 17) preoperatively to 70 (SD 20) (p < 0.001) at last follow-up. Conclusion. Revision TAA offers acceptable survival rates after 15 years; it therefore offers a valuable option for treatment of implant failure in carefully selected cases. Although patient-reported outcomes improve substantially, the degree of improvement reported following primary TAA is not achieved. Cite this article: Bone Joint J 2024;106-B(1):46–52

Aims. Dual-mobility (DM) components are increasingly used to prevent and treat dislocation after total hip arthroplasty (THA). Intraprosthetic dissociation (IPD) is a rare complication of DM that is believed to have decreased with contemporary implants. This study aimed to report incidence, treatment, and outcomes of contemporary DM IPD. Methods. A total of 1,453 DM components were implanted at a single academic institution between January 2010 and December 2021: 695 in primary and 758 in revision THA. Of these, 49 presented with a dislocation of the large DM head and five presented with an IPD. At the time of closed reduction of the large DM dislocation, six additional IPDs occurred. The mean age was 64 years (SD 9.6), 54.5% were female (n = 6), and mean follow-up was 4.2 years (SD 1.8). Of the 11 IPDs, seven had a history of instability, five had abductor insufficiency, four had prior lumbar fusion, and two were conversions for failed fracture management. Results. The incidence of IPD was 0.76%. Of the 11 IPDs, ten were missed either at presentation or after attempted reduction. All ten patients with a missed IPD were discharged with a presumed reduction. The mean time from IPD to surgical treatment was three weeks (0 to 23). One patient died after IPD prior to revision. Of the ten remaining hips with IPD, the DM head was exchanged in two, four underwent acetabular revision with DM exchange, and four were revised to a constrained liner. Of these, five (50%) underwent reoperation at a mean 1.8 years (SD 0.73), including one additional acetabular revision. No patients who underwent initial acetabular revision for IPD treatment required subsequent reoperation. Conclusion. The overall rate of IPD was low at 0.76%. It is essential to identify an IPD on radiographs as the majority were missed at presentation or after iatrogenic dissociation. Surgeons should consider acetabular revision for IPD to allow conversion to a larger DM head, and take care to remove impinging structures that may increase the risk of subsequent failure. Cite this article: Bone Joint J 2024;106-B(5 Supple B):98–104

Aims. Brace treatment is the cornerstone of managing developmental dysplasia of the hip (DDH), yet there is a lack of evidence-based treatment protocols, which results in wide variations in practice. To resolve this, we have developed a comprehensive nonoperative treatment protocol conforming to published consensus principles, with well-defined a priori criteria for inclusion and successful treatment. Methods. This was a single-centre, prospective, longitudinal cohort study of a consecutive series of infants with ultrasound-confirmed DDH who underwent a comprehensive nonoperative brace management protocol in a unified multidisciplinary clinic between January 2012 and December 2016 with five-year follow-up radiographs. The radiological outcomes were acetabular index-lateral edge (AI-L), acetabular index-sourcil (AI-S), centre-edge angle (CEA), acetabular depth ratio (ADR), International Hip Dysplasia Institute (IHDI) grade, and evidence of avascular necrosis (AVN). At five years, each hip was classified as normal (< 1 SD), borderline dysplastic (1 to 2 SDs), or dysplastic (> 2 SDs) based on validated radiological norm-referenced values. Results. Of 993 infants assessed clinically and sonographically, 21% (212 infants, 354 abnormal hips) had DDH and were included. Of these, 95% (202 infants, 335 hips) successfully completed bracing, and 5% (ten infants, 19 hips) failed bracing due to irreducible hip(s). The success rate of bracing for unilateral dislocations was 88% (45/51 infants) and for bilateral dislocations 83% (20/24 infants). The femoral nerve palsy rate was 1% (2/212 infants). At five-year follow-up (mean 63 months (SD 5.9; 49 to 83)) the prevalence of residual dysplasia after successful brace treatment was 1.6% (5/312 hips). All hips were IHDI grade I and none had AVN. Four children (4/186; 2%) subsequently underwent surgery for residual dysplasia. Conclusion. Our comprehensive protocol for nonoperative treatment of infant DDH has shown high rates of success and extremely low rates of residual dysplasia at a mean age of five years. Cite this article: Bone Joint J 2023;105-B(8):935–942

Aims. There is a lack of published evidence relating to the rate of nonunion seen in occult scaphoid fractures, diagnosed only after MRI. This study reports the rate of delayed union and nonunion in a cohort of patients with MRI-detected acute scaphoid fractures. Methods. This multicentre cohort study at eight centres in the UK included all patients with an acute scaphoid fracture diagnosed on MRI having presented acutely following wrist trauma with normal radiographs. Data were gathered retrospectively for a minimum of 12 months at each centre. The primary outcome measures were the rate of acute surgery, delayed union, and nonunion. Results. A total of 1,989 patients underwent acute MRI for a suspected scaphoid fracture during the study period, of which 256 patients (12.9%) were diagnosed with a previously occult scaphoid fracture. Of the patients with scaphoid fractures, six underwent early surgical fixation (2.3%) and there was a total of 16 cases of delayed or nonunion (6.3%) in the remaining 250 patients treated with cast immobilization. Of the nine nonunions (3.5%), seven underwent surgery (2.7%), one opted for non-surgical treatment, and one failed to attend follow-up. Of the seven delayed unions (2.7%), one (0.4%) was treated with surgery at two months, one (0.4%) did not attend further follow-up, and the remaining five fractures (1.9%) healed after further cast immobilization. All fractures treated with surgery had united at follow-up. There was one complication of surgery (prominent screw requiring removal). Conclusion. MRI-detected scaphoid fractures are not universally benign, with delayed or nonunion of scaphoid fractures diagnosed only after MRI seen in over 6% despite appropriate initial immobilization, with most of these patients with nonunion requiring surgery to achieve union. This study adds weight to the evidence base supporting the use of early MRI for these patients. Cite this article: Bone Joint J 2024;106-B(4):387–393