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The Bone & Joint Journal
Vol. 100-B, Issue 2 | Pages 242 - 246
1 Feb 2018
Ghoshal A Enninghorst N Sisak K Balogh ZJ

Aims. To evaluate interobserver reliability of the Orthopaedic Trauma Association’s open fracture classification system (OTA-OFC). Patients and Methods. Patients of any age with a first presentation of an open long bone fracture were included. Standard radiographs, wound photographs, and a short clinical description were given to eight orthopaedic surgeons, who independently evaluated the injury using both the Gustilo and Anderson (GA) and OTA-OFC classifications. The responses were compared for variability using Cohen’s kappa. Results. The overall interobserver agreement was ĸ = 0.44 for the GA classification and ĸ = 0.49 for OTA-OFC, which reflects moderate agreement (0.41 to 0.60) for both classifications. The agreement in the five categories of OTA-OFC was: for skin, ĸ = 0.55 (moderate); for muscle, ĸ = 0.44 (moderate); for arterial injury, ĸ = 0.74 (substantial); for contamination, ĸ = 0.35 (fair); and for bone loss, ĸ = 0.41 (moderate). Conclusion. Although the OTA-OFC, with similar interobserver agreement to GA, offers a more detailed description of open fractures, further development may be needed to make it a reliable and robust tool. Cite this article: Bone Joint J 2018;100-B:242–6


The Bone & Joint Journal
Vol. 101-B, Issue 7_Supple_C | Pages 64 - 69
1 Jul 2019
Wodowski AJ Pelt CE Erickson JA Anderson MB Gililland JM Peters CL

Aims. The Bundled Payments for Care Improvement (BPCI) initiative has identified pathways for improving the value of care. However, patient-specific modifiable and non-modifiable risk factors may increase costs beyond the target payment. We sought to identify risk factors for exceeding our institution’s target payment, the so-called ‘bundle busters’. Patients and Methods. Using our data warehouse and Centers for Medicare and Medicaid Services (CMS) data we identified all 412 patients who underwent total joint arthroplasty and qualified for our institution’s BPCI model, between July 2015 and May 2017. Episodes where CMS payments exceeded the target payment were considered ‘busters’ (n = 123). Risk ratios (RRs) were calculated using a modified Poisson regression analysis. Results. An increased risk of exceeding the target payment was significantly associated with increasing age (adjusted RR 1.04, 95% confidence interval (CI) 1.01 to 1.06) and body mass index (adjusted RR 1.03, 95% CI 1.003 to 1.06). Eight comorbid risk factors were also identified (all p < 0.05), only two of which were considered to be potentially modifiable (diabetes with complications and preoperative anaemia). An American Society of Anesthesiologist physical status classification system (ASA) score ≥ 3 (adjusted RR 2.3, 95% CI 1.67 to 3.18) and Charlson Comorbidity Index (CCI) ≥ 3 (adjusted RR 1.94, 95% CI 1.45 to 2.60) were risk factors for bundle busting. Conclusion. Non-modifiable preoperative risk factors can increase costs and exceed the target payment. Future bundled payment models should incorporate the stratification of risk. Cite this article: Bone Joint J 2019;101-B(7 Supple C):64–69


The Bone & Joint Journal
Vol. 100-B, Issue 2 | Pages 176 - 182
1 Feb 2018
Petrie MJ Blakey CM Chadwick C Davies HG Blundell CM Davies MB

Aims. Fractures of the navicular can occur in isolation but, owing to the intimate anatomical and biomechanical relationships, are often associated with other injuries to the neighbouring bones and joints in the foot. As a result, they can lead to long-term morbidity and poor function. Our aim in this study was to identify patterns of injury in a new classification system of traumatic fractures of the navicular, with consideration being given to the commonly associated injuries to the midfoot. Patients and Methods. We undertook a retrospective review of 285 consecutive patients presenting over an eight- year period with a fracture of the navicular. Five common patterns of injury were identified and classified according to the radiological features. Type 1 fractures are dorsal avulsion injuries related to the capsule of the talonavicular joint. Type 2 fractures are isolated avulsion injuries to the tuberosity of the navicular. Type 3 fractures are a variant of tarsometatarsal fracture/dislocations creating instability of the medial ray. Type 4 fractures involve the body of the navicular with no associated injury to the lateral column and type 5 fractures occur in conjunction with disruption of the midtarsal joint with crushing of the medial or lateral, or both, columns of the foot. Results. In order to test the reliability and reproducibility of this new classification, a cohort of 30 patients with a fracture of the navicular were classified by six independent assessors at two separate times, six months apart. Interobserver reliability and intraobserver reproducibility both had substantial agreement, with kappa values of 0.80 and 0.72, respectively. Conclusion. We propose a logical, all-inclusive, and mutually exclusive classification system for fractures of the navicular that gives associated injuries involving the lateral column due consideration. We have shown that this system is reliable and reproducible and have described the rationale for the subsequent treatment of each type. Cite this article: Bone Joint J 2018;100-B:176–82


The Bone & Joint Journal
Vol. 100-B, Issue 4 | Pages 468 - 474
1 Apr 2018
Kirzner N Zotov P Goldbloom D Curry H Bedi H

Aims. The aim of this retrospective study was to compare the functional and radiological outcomes of bridge plating, screw fixation, and a combination of both methods for the treatment of Lisfranc fracture dislocations. Patients and Methods. A total of 108 patients were treated for a Lisfranc fracture dislocation over a period of nine years. Of these, 38 underwent transarticular screw fixation, 45 dorsal bridge plating, and 25 a combination technique. Injuries were assessed preoperatively according to the Myerson classification system. The outcome measures included the American Orthopaedic Foot and Ankle Society (AOFAS) score, the validated Manchester Oxford Foot Questionnaire (MOXFQ) functional tool, and the radiological Wilppula classification of anatomical reduction. Results. Significantly better functional outcomes were seen in the bridge plate group. These patients had a mean AOFAS score of 82.5 points, compared with 71.0 for the screw group and 63.3 for the combination group (p < 0.001). Similarly, the mean Manchester Oxford Foot Questionnaire score was 25.6 points in the bridge plate group, 38.1 in the screw group, and 45.5 in the combination group (p < 0.001). Functional outcome was dependent on the quality of reduction (p < 0.001). A trend was noted which indicated that plate fixation is associated with a better anatomical reduction (p = 0.06). Myerson types A and C2 significantly predicted a poorer functional outcome, suggesting that total incongruity in either a homolateral or divergent pattern leads to worse outcomes. The greater the number of columns fixed the worse the outcome (p < 0.001). Conclusion. Patients treated with dorsal bridge plating have better functional and radiological outcomes than those treated with transarticular screws or a combination technique. Cite this article: Bone Joint J 2018;100-B:468–74


Bone & Joint Research
Vol. 6, Issue 8 | Pages 481 - 488
1 Aug 2017
Caruso G Bonomo M Valpiani G Salvatori G Gildone A Lorusso V Massari L

Objectives. Intramedullary fixation is considered the most stable treatment for pertrochanteric fractures of the proximal femur and cut-out is one of the most frequent mechanical complications. In order to determine the role of clinical variables and radiological parameters in predicting the risk of this complication, we analysed the data pertaining to a group of patients recruited over the course of six years. Methods. A total of 571 patients were included in this study, which analysed the incidence of cut-out in relation to several clinical variables: age; gender; the AO Foundation and Orthopaedic Trauma Association classification system (AO/OTA); type of nail; cervical-diaphyseal angle; surgical wait times; anti-osteoporotic medication; complete post-operative weight bearing; and radiological parameters (namely the lag-screw position with respect to the femoral head, the Cleveland system, the tip-apex distance (TAD), and the calcar-referenced tip-apex distance (CalTAD)). Results. The incidence of cut-out across the sample was 5.6%, with a higher incidence in female patients. A significantly higher risk of this complication was correlated with lag-screw tip positioning in the upper part of the femoral head in the anteroposterior radiological view, posterior in the latero-lateral radiological view, and in the Cleveland peripheral zones. The tip-apex distance and the calcar-referenced tip-apex distance were found to be highly significant predictors of the risk of cut-out at cut-offs of 30.7 mm and 37.3 mm, respectively, but the former appeared more reliable than the latter in predicting the occurrence of this complication. Conclusion. The tip-apex distance remains the most accurate predictor of cut-out, which is significantly greater above a cut-off of 30.7 mm. Cite this article: G. Caruso, M. Bonomo, G. Valpiani, G. Salvatori, A. Gildone, V. Lorusso, L. Massari. A six-year retrospective analysis of cut-out risk predictors in cephalomedullary nailing for pertrochanteric fractures: Can the tip-apex distance (TAD) still be considered the best parameter?. Bone Joint Res 2017;6:481–488. DOI: 10.1302/2046-3758.68.BJR-2016-0299.R1


The Bone & Joint Journal
Vol. 106-B, Issue 10 | Pages 1125 - 1132
1 Oct 2024
Luengo-Alonso G Valencia M Martinez-Catalan N Delgado C Calvo E

Aims

The prevalence of osteoarthritis (OA) associated with instability of the shoulder ranges between 4% and 60%. Articular cartilage is, however, routinely assessed in these patients using radiographs or scans (2D or 3D), with little opportunity to record early signs of cartilage damage. The aim of this study was to assess the prevalence and localization of chondral lesions and synovial damage in patients undergoing arthroscopic surgery for instablility of the shoulder, in order to classify them and to identify risk factors for the development of glenohumeral OA.

Methods

A total of 140 shoulders in 140 patients with a mean age of 28.5 years (15 to 55), who underwent arthroscopic treatment for recurrent glenohumeral instability, were included. The prevalence and distribution of chondral lesions and synovial damage were analyzed and graded into stages according to the division of the humeral head and glenoid into quadrants. The following factors that might affect the prevalence and severity of chondral damage were recorded: sex, dominance, age, age at the time of the first dislocation, number of dislocations, time between the first dislocation and surgery, preoperative sporting activity, Beighton score, type of instability, and joint laxity.


The Bone & Joint Journal
Vol. 105-B, Issue 7 | Pages 743 - 750
1 Jul 2023
Fujii M Kawano S Ueno M Sonohata M Kitajima M Tanaka S Mawatari D Mawatari M

Aims

To clarify the mid-term results of transposition osteotomy of the acetabulum (TOA), a type of spherical periacetabular osteotomy, combined with structural allograft bone grafting for severe hip dysplasia.

Methods

We reviewed patients with severe hip dysplasia, defined as Severin IVb or V (lateral centre-edge angle (LCEA) < 0°), who underwent TOA with a structural bone allograft between 1998 and 2019. A medical chart review was conducted to extract demographic data, complications related to the osteotomy, and modified Harris Hip Score (mHHS). Radiological parameters of hip dysplasia were measured on pre- and postoperative radiographs. The cumulative probability of TOA failure (progression to Tönnis grade 3 or conversion to total hip arthroplasty) was estimated using the Kaplan–Meier product-limited method, and a multivariate Cox proportional hazard model was used to identify predictors for failure.


The Bone & Joint Journal
Vol. 98-B, Issue 7 | Pages 1003 - 1008
1 Jul 2016
Fenton P Al-Nammari S Blundell C Davies M

Aims. Although infrequent, a fracture of the cuboid can lead to significant disruption of the integrity of the midfoot and its function. The purpose of this study was to classify the pattern of fractures of the cuboid, relate them to the mechanism of injury and suggest methods of managing them. Patients and Methods. We performed a retrospective review of patients with radiologically reported cuboid fractures. Fractures were grouped according to commonly occurring patterns of injury. A total of 192 fractures in 188 patients were included. They were classified into five patterns of injury. Results. Type 1 fractures (93 fractures, 48.4%) are simple avulsion injuries involving the capsule of the calcaneo-cuboid joint. Type 2 fractures (25 fractures, 13%) are isolated extra-articular injuries involving the body of the cuboid. Type 3 injuries (13 factures, 6.8%) are intra-articular fractures solely within the body of the cuboid. Type 4 fractures (35 fractures, 18.2%) are associated with disruption of the midfoot and tarsometatarsal injuries. Type 5 fractures (26 fractures, 13.5%) occur in conjunction with disruption of the mid-tarsal joint and either crushing of the lateral column alone or of both medial and lateral columns. Fractures with significant articular disruption or with loss of length of the lateral column underwent fixation. This involved either internal fixation to restore the anatomy of the cuboid and/or restoration of the length of the columns with bridging constructs using internal or external fixation. Conclusion. A classification system for fractures of the cuboid is proposed in relation to the mechanism of injury. The treatment of these fractures is described. Cite this article: Bone Joint J 2016;98-B:1003–8


The Bone & Joint Journal
Vol. 106-B, Issue 5 | Pages 468 - 474
1 May 2024
d'Amato M Flevas DA Salari P Bornes TD Brenneis M Boettner F Sculco PK Baldini A

Aims

Obtaining solid implant fixation is crucial in revision total knee arthroplasty (rTKA) to avoid aseptic loosening, a major reason for re-revision. This study aims to validate a novel grading system that quantifies implant fixation across three anatomical zones (epiphysis, metaphysis, diaphysis).

Methods

Based on pre-, intra-, and postoperative assessments, the novel grading system allocates a quantitative score (0, 0.5, or 1 point) for the quality of fixation achieved in each anatomical zone. The criteria used by the algorithm to assign the score include the bone quality, the size of the bone defect, and the type of fixation used. A consecutive cohort of 245 patients undergoing rTKA from 2012 to 2018 were evaluated using the current novel scoring system and followed prospectively. In addition, 100 first-time revision cases were assessed radiologically from the original cohort and graded by three observers to evaluate the intra- and inter-rater reliability of the novel radiological grading system.


The Bone & Joint Journal
Vol. 106-B, Issue 5 | Pages 442 - 449
1 May 2024
Nieboer MF van der Jagt OP de Munter L de Jongh MAC van de Ree CLP

Aims

Periprosthetic proximal femoral fractures (PFFs) are a major complication after total hip arthroplasty (THA). Health status after PFF is not specifically investigated. The aim of this study is to evaluate the health status pattern over two years after sustaining a PFF.

Methods

A cohort of patients with PFF after THA was derived from the Brabant Injury Outcomes Surveillance (BIOS) study. The BIOS study, a prospective, observational, multicentre follow-up cohort study, was conducted to obtain data by questionnaires pre-injury and at one week, and one, three, six, 12, and 24 months after trauma. Primary outcome measures were the EuroQol five-dimension three-level questionnaire (EQ-5D-3L), the Health Utility Index 2 (HUI2), and the Health Utility Index 3 (HUI3). Secondary outcome measures were general measurements such as duration of hospital stay and mortality.


The Bone & Joint Journal
Vol. 105-B, Issue 7 | Pages 760 - 767
1 Jul 2023
Tanaka S Fujii M Kawano S Ueno M Sonohata M Kitajima M Mawatari D Mawatari M

Aims

The aims of this study were to validate the Forgotten Joint Score-12 (FJS-12) in the postoperative evaluation of periacetabular osteotomy (PAO), identify factors associated with joint awareness after PAO, and determine the FJS-12 threshold for patient-acceptable symptom state (PASS).

Methods

Data from 686 patients (882 hips) with hip dysplasia who underwent transposition osteotomy of the acetabulum, a type of PAO, between 1998 and 2019 were reviewed. After screening the study included 442 patients (582 hips; response rate, 78%). Patients who completed a study questionnaire consisting of the visual analogue scale (VAS) for pain and satisfaction, FJS-12, and Hip disability and Osteoarthritis Outcome Score (HOOS) were included. The ceiling effects, internal consistency, convergent validity, and PASS thresholds of FJS-12 were investigated.


The Bone & Joint Journal
Vol. 97-B, Issue 7 | Pages 899 - 904
1 Jul 2015
Arduini M Mancini F Farsetti P Piperno A Ippolito E

In this paper we propose a new classification of neurogenic peri-articular heterotopic ossification (HO) of the hip based on three-dimensional (3D) CT, with the aim of improving pre-operative planning for its excision. . A total of 55 patients (73 hips) with clinically significant HO after either traumatic brain or spinal cord injury were assessed by 3D-CT scanning, and the results compared with the intra-operative findings. At operation, the gross pathological anatomy of the HO as identified by 3D-CT imaging was confirmed as affecting the peri-articular hip muscles to a greater or lesser extent. We identified seven patterns of involvement: four basic (anterior, medial, posterior and lateral) and three mixed (anteromedial, posterolateral and circumferential). Excellent intra- and inter-observer agreement, with kappa values > 0.8, confirmed the reproducibility of the classification system. We describe the different surgical approaches used to excise the HO which were guided by the 3D-CT findings. Resection was always successful. . 3D-CT imaging, complemented in some cases by angiography, allows the surgeon to define the 3D anatomy of the HO accurately and to plan its surgical excision with precision. Cite this article: Bone Joint J 2015; 97-B:899–904


The Bone & Joint Journal
Vol. 105-B, Issue 2 | Pages 112 - 123
1 Feb 2023
Duckworth AD Carter TH Chen MJ Gardner MJ Watts AC

Despite being one of the most common injuries around the elbow, the optimal treatment of olecranon fractures is far from established and stimulates debate among both general orthopaedic trauma surgeons and upper limb specialists. It is almost universally accepted that stable non-displaced fractures can be safely treated nonoperatively with minimal specialist input. Internal fixation is recommended for the vast majority of displaced fractures, with a range of techniques and implants to choose from. However, there is concern regarding the complication rates, largely related to symptomatic metalwork resulting in high rates of implant removal. As the number of elderly patients sustaining these injuries increases, we are becoming more aware of the issues associated with fixation in osteoporotic bone and the often fragile soft-tissue envelope in this group. Given this, there is evidence to support an increasing role for nonoperative management in this high-risk demographic group, even in those presenting with displaced and/or multifragmentary fracture patterns. This review summarizes the available literature to date, focusing predominantly on the management techniques and available implants for stable fractures of the olecranon. It also offers some insights into the potential avenues for future research, in the hope of addressing some of the pertinent questions that remain unanswered.

Cite this article: Bone Joint J 2023;105-B(2):112–123.


Bone & Joint Open
Vol. 4, Issue 8 | Pages 559 - 566
1 Aug 2023
Hillier DI Petrie MJ Harrison TP Salih S Gordon A Buckley SC Kerry RM Hamer A

Aims

The burden of revision total hip arthroplasty (rTHA) continues to grow. The surgery is complex and associated with significant costs. Regional rTHA networks have been proposed to improve outcomes and to reduce re-revisions, and therefore costs. The aim of this study was to accurately quantify the cost and reimbursement for a rTHA service, and to assess the financial impact of case complexity at a tertiary referral centre within the NHS.

Methods

A retrospective analysis of all revision hip procedures was performed at this centre over two consecutive financial years (2018 to 2020). Cases were classified according to the Revision Hip Complexity Classification (RHCC) and whether they were infected or non-infected. Patients with an American Society of Anesthesiologists (ASA) grade ≥ III or BMI ≥ 40 kg/m2 are considered “high risk” by the RHCC. Costs were calculated using the Patient Level Information and Costing System (PLICS), and remuneration based on Healthcare Resource Groups (HRG) data. The primary outcome was the financial difference between tariff and cost per patient episode.


Bone & Joint 360
Vol. 12, Issue 6 | Pages 36 - 39
1 Dec 2023

The December 2023 Trauma Roundup360 looks at: Distal femoral arthroplasty: medical risks under the spotlight; Quads repair: tunnels or anchors?; Complex trade-offs in treating severe tibial fractures: limb salvage versus primary amputation; Middle-sized posterior malleolus fractures – to fix?; Bone transport through induced membrane: a randomized controlled trial; Displaced geriatric femoral neck fractures; Risk factors for reoperation to promote union in 1,111 distal femur fractures; New versus old – reliability of the OTA/AO classification for trochanteric hip fractures; Risk factors for fracture-related infection after ankle fracture surgery.


The Bone & Joint Journal
Vol. 106-B, Issue 5 Supple B | Pages 98 - 104
1 May 2024
Mallett KE Guarin Perez SF Taunton MJ Sierra RJ

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.


The Bone & Joint Journal
Vol. 105-B, Issue 12 | Pages 1314 - 1320
1 Dec 2023
Broida SE Sullivan MH Barlow JD Morrey M Scorianz M Wagner ER Sanchez-Sotelo J Rose PS Houdek MT

Aims

The scapula is a rare site for a primary bone tumour. Only a small number of series have studied patient outcomes after treatment. Previous studies have shown a high rate of recurrence, with functional outcomes determined by the preservation of the glenohumeral joint and deltoid. The purpose of the current study was to report the outcome of patients who had undergone tumour resection that included the scapula.

Methods

We reviewed 61 patients (37 male, 24 female; mean age 42 years (SD 19)) who had undergone resection of the scapula. The most common resection was type 2 (n = 34) according to the Tikhoff-Linberg classification, or type S1A (n = 35) on the Enneking classification.


The Bone & Joint Journal
Vol. 106-B, Issue 12 | Pages 1399 - 1407
1 Dec 2024
Fujii M Tanaka S Kawano S Ueno M Nagamine S Mawatari M

Aims

This study aimed to determine clinical outcomes; relationships between postoperative anterior, lateral, and posterior acetabular coverage and joint survival; and prognostic factors for joint survival after transposition osteotomy of the acetabulum (TOA).

Methods

Data from 616 patients (800 hips) with hip dysplasia who underwent TOA between November 1998 and December 2019 were reviewed. The median follow-up period was 8.9 years (IQR 5 to 14). A medical notes review was conducted to collect demographic data, complications, and modified Harris Hip Score (mHHS). Radiological indicators of acetabular coverage included lateral centre-edge angle (LCEA), anterior wall index (AWI), and posterior wall index (PWI). The cumulative probability of TOA failure (progression to Tönnis grade 3 or conversion to total hip arthroplasty) was estimated using the Kaplan-Meier product-limited method. A multivariate Cox proportional hazards model was used to identify predictors for failure.


The Bone & Joint Journal
Vol. 106-B, Issue 1 | Pages 19 - 27
1 Jan 2024
Tang H Guo S Ma Z Wang S Zhou Y

Aims

The aim of this study was to evaluate the reliability and validity of a patient-specific algorithm which we developed for predicting changes in sagittal pelvic tilt after total hip arthroplasty (THA).

Methods

This retrospective study included 143 patients who underwent 171 THAs between April 2019 and October 2020 and had full-body lateral radiographs preoperatively and at one year postoperatively. We measured the pelvic incidence (PI), the sagittal vertical axis (SVA), pelvic tilt, sacral slope (SS), lumbar lordosis (LL), and thoracic kyphosis to classify patients into types A, B1, B2, B3, and C. The change of pelvic tilt was predicted according to the normal range of SVA (0 mm to 50 mm) for types A, B1, B2, and B3, and based on the absolute value of one-third of the PI-LL mismatch for type C patients. The reliability of the classification of the patients and the prediction of the change of pelvic tilt were assessed using kappa values and intraclass correlation coefficients (ICCs), respectively. Validity was assessed using the overall mean error and mean absolute error (MAE) for the prediction of the change of pelvic tilt.


Bone & Joint Research
Vol. 5, Issue 10 | Pages 512 - 519
1 Oct 2016
Mills L Tsang J Hopper G Keenan G Simpson AHRW

Objectives. A successful outcome following treatment of nonunion requires the correct identification of all of the underlying cause(s) and addressing them appropriately. The aim of this study was to assess the distribution and frequency of causative factors in a consecutive cohort of nonunion patients in order to optimise the management strategy for individual patients presenting with nonunion. Methods. Causes of the nonunion were divided into four categories: mechanical; infection; dead bone with a gap; and host. Prospective and retrospective data of 100 consecutive patients who had undergone surgery for long bone fracture nonunion were analysed. Results. A total of 31% of patients had a single attributable cause, 55% had two causes, 14% had three causes and 1% had all four. Of those (31%) with only a single attributable cause, half were due to a mechanical factor and a quarter had dead bone with a gap. Mechanical causation was found in 59% of all patients, dead bone and a gap was present in 47%, host factors in 43% and infection was a causative factor in 38% of patients. In all, three of 58 patients (5%) thought to be aseptic and two of nine (22%) suspected of possible infection were found to be infected. A total of 100% of previously treated patients no longer considered to have ongoing infection, had multiple positive microbiology results. Conclusion. Two thirds of patients had multiple contributing factors for their nonunion and 5% had entirely unexpected infection. This study highlights the importance of identifying all of the aetiological factors and routinely testing tissue for infection in treating nonunion. It raises key points regarding the inadequacy of a purely radiographic nonunion classification system and the variety of different definitions for atrophic nonunion in the current mainstream classifications used for nonunion. Cite this article: L. Mills, J. Tsang, G. Hopper, G. Keenan, A. H. R. W. Simpson. The multifactorial aetiology of fracture nonunion and the importance of searching for latent infection. Bone Joint Res 2016;5:512–519. DOI: 10.1302/2046-3758.510.BJR-2016-0138