Aims. This study aims to describe a new method that may be used as a supplement to evaluate humeral rotational alignment during intramedullary nail (IMN) insertion using the profile of the perpendicular peak of the greater tuberosity and its relation to the transepicondylar axis. We called this angle the greater tuberosity version angle (GTVA). Methods. This study analyzed 506 cadaveric humeri of adult patients. All humeri were CT scanned using 0.625 × 0.625 × 0.625 mm cubic voxels. The images acquired were used to generate 3D surface models of the humerus. Next, 3D landmarks were automatically calculated on each 3D bone using custom-written C++ software. The anatomical landmarks analyzed were the transepicondylar axis, the humerus anatomical axis, and the peak of the perpendicular axis of the greater tuberosity. Lastly, the angle between the transepicondylar axis and the greater tuberosity axis was calculated and defined as the GTVA. Results. The value of GTVA was 20.9° (SD 4.7°) (95% CI 20.47° to 21.3°). Results of analysis of variance revealed that females had a statistically significant larger angle of 21.95° (SD 4.49°) compared to males, which were found to be 20.49° (SD 4.8°) (p = 0.001). Conclusion. This study identified a consistent relationship between palpable anatomical landmarks, enhancing IMN accuracy by utilizing 3D CT scans and replicating a 20.9° angle from the greater tuberosity to the transepicondylar axis. Using this angle as a secondary reference may help mitigate the complications associated with malrotation of the humerus following IMN. However, future trials are needed for clinical validation. Cite this article: Bone Jt Open 2024;5(10):929–936

Aims. The objective of this study was to compare simulated range of motion (ROM) for reverse total shoulder arthroplasty (rTSA) with and without adjustment for scapulothoracic orientation in a global reference system. We hypothesized that values for simulated ROM in preoperative planning software with and without adjustment for scapulothoracic orientation would be significantly different. Methods. A statistical shape model of the entire humerus and scapula was fitted into ten shoulder CT scans randomly selected from 162 patients who underwent rTSA. Six shoulder surgeons independently planned a rTSA in each model using prototype development software with the ability to adjust for scapulothoracic orientation, the starting position of the humerus, as well as kinematic planes in a global reference system simulating previously described posture types A, B, and C. ROM with and without posture adjustment was calculated and compared in all movement planes. Results. All movement planes showed significant differences when comparing protocols with and without adjustment for posture. The largest mean difference was seen in external rotation, being 62° (SD 16°) without adjustment compared to 25° (SD 9°) with posture adjustment (p < 0.001), with the highest mean difference being 49° (SD 15°) in type C. Mean extension was 57° (SD 18°) without adjustment versus 24° (SD 11°) with adjustment (p < 0.001) and the highest mean difference of 47° (SD 18°) in type C. Mean abducted internal rotation was 69° (SD 11°) without adjustment versus 31° (SD 6°) with posture adjustment (p < 0.001), showing the highest mean difference of 51° (SD 11°) in type C. Conclusion. The present study demonstrates that accounting for scapulothoracic orientation has a significant impact on simulated ROM for rTSA in all motion planes, specifically rendering vastly lower values for external rotation, extension, and high internal rotation. The substantial differences observed in this study warrant a critical re-evaluation of all previously published studies that examined component choice and placement for optimized ROM in rTSA using conventional preoperative planning software. Cite this article: Bone Joint J 2024;106-B(11):1284–1292

Aims. Fracture-related infection (FRI) is commonly classified based on the time of onset of symptoms. Early infections (< two weeks) are treated with debridement, antibiotics, and implant retention (DAIR). For late infections (> ten weeks), guidelines recommend implant removal due to tolerant biofilms. For delayed infections (two to ten weeks), recommendations are unclear. In this study we compared infection clearance and bone healing in early and delayed FRI treated with DAIR in a rabbit model. Methods. Staphylococcus aureus was inoculated into a humeral osteotomy in 17 rabbits after plate osteosynthesis. Infection developed for one week (early group, n = 6) or four weeks (delayed group, n = 6) before DAIR (systemic antibiotics: two weeks, nafcillin + rifampin; four weeks, levofloxacin + rifampin). A control group (n = 5) received revision surgery after four weeks without antibiotics. Bacteriology of humerus, soft-tissue, and implants was performed seven weeks after revision surgery. Bone healing was assessed using a modified radiological union scale in tibial fractures (mRUST). Results. Greater bacterial burden in the early group compared to the delayed and control groups at revision surgery indicates a retraction of the infection from one to four weeks. Infection was cleared in all animals in the early and delayed groups at euthanasia, but not in the control group. Osteotomies healed in the early group, but bone healing was significantly compromised in the delayed and control groups. Conclusion. The duration of the infection from one to four weeks does not impact the success of infection clearance in this model. Bone healing, however, is impaired as the duration of the infection increases. Cite this article: Bone Joint Res 2024;13(3):127–135

To evaluate the functional outcome of open humerus diaphyseal fractures treated with the Three-stitch technique of antegrade humerus nailing. This is a retrospective study conducted at the Department of Orthopaedics in D. Y. Patil University, School of Medicine, Navi Mumbai, India. The study included 25 patients who were operated on from January 2019 to April 2021 and follow-ups done till May 2022. Inclusion criteria were adult patients with open humerus diaphyseal fractures (Gustilo-Anderson Classification). All patients with closed fractures, skeletally immature patients, and patients with associated head injury were excluded from the study. All patients were operated on with a minimally invasive Three-stitch technique for antegrade humerus nailing. All patients were evaluated based on DASH score. Out of the 25 patients included in the study, all patients showed complete union. The mean age of the patients was 40.4 years (range 23–66 years). The average period for consolidation of fracture was 10.56 weeks (range 8–14 weeks). The DASH score ranged from 0 to 15.8 with an average score of 2.96. Five patients reported complications with three patients of post-operative infection and delayed wound healing and two patients with screw loosening. All complications were resolved with proper wound care and the complete union was noted. None of the patients had an iatrogenic neurovascular injury. Three-stitch antegrade nailing technique is a novel method to treat diaphyseal humerus fractures and provides excellent results. It has various advantages such as minimal invasiveness, minimal injury to the rotator cuff, fewer infection rates, minimal iatrogenic injuries, and good functional outcomes. Therefore, this treatment modality can be effectively used for open humerus diaphyseal fractures

Introduction. Fully implantable distraction nails are frequently used for lengthening of the lower leg. What are the indications for humerus lengthening and which results can be expected?. Materials and Methods. The humerus as the best healing bone in the human body is suitable for lengthening with a nail as well but the indications are rare in comparison with the lower legs. Especially when driving a car or when working on a tablet length discrepancy of the arms of more than 4–5cm may cause severe hardening of the cervical muscles and induce chronical pain in the upper spine. Results. A distraction nail (FITBONE) was used in 5 cases for humerus lengthening. The nail was inserted in all cases from proximal. The mean age of the patients was 34 years. The mean lengthening amount was 58mm (55–100). In one case the system was exchanged to reach the desired length. There was no infection, no radial nerve irritation and no chronical shoulder pain. The system was removed in 4 cases in an average of 15 months the other nail will be removed soon as well. Conclusions. The preliminary results of our 5 cases demonstrate, that the FITBONE device is advantageous for lengthening the humerus, if the initial length is sufficient for implantation. In comparison with the use of external fixators the functional outcome, the comfort of treatment and the cosmetic result is amazing

Introduction. The Walch Type B2 glenoid has the hallmark features of posteroinferior glenoid erosion, retroversion, and posterior humeral head subluxation. Although our understanding of the pathoanatomy of bone loss and its evolution in Type B's has improved, the etiology remains unclear. Furthermore, the morphology of the humerus in Walch B types has not been studied. The purpose of this imaging based anthropometric study was to examine the humeral torsion in Walch Type B2 shoulders. We hypothesized that there would be a compensatory decrease in humeral retroversion in Walch B2 glenoids. Methods. Three-dimensional models of the full length humerus were generated from computed tomography data of normal cadaveric (n = 59) and Walch Type B shoulders (n = 59). An anatomical coordinate system referencing the medial and lateral epicondyles was created for each model. A simulated humeral head osteotomy plane was created and used to determine humeral version relative to the epicondylar axis and the head-neck angle. Measurements were repeated by two experienced fellowship-trained shoulder surgeons to determine inter-rater reliability. Glenoid parameters (version, inclination and 2D critical shoulder angle) and posterior humeral head subluxation were calculated in the Type B group to determine the pathologic glenohumeral relationship. Two-way ANOVAs compared group and sex within humeral version and head-neck angle, and intra-class correlation coefficients (ICCs) with a 2-way random effects model and absolute agreement were used for inter-rater reliability. Results. There were statistically significant differences in humeral version between normal and Type B shoulders (p < .001) and between males and females within the normal group (p = .043). Normal shoulders had a humeral retroversion of 36±12°, while the Walch Type B group had a humeral retroversion of 14±9° relative to the epicondylar axis. For head-neck angle, there were no significant differences between sexes (p = .854), or between normal and Type B shoulders when grouped by sex (p = .433). In the Type B group, the mean glenoid version was 22±7°, glenoid inclination was 8±6°, 2D critical shoulder angle was 30±5° and humeral head subluxation was 80±9%. Inter-rater reliability showed fair agreement between the two experienced observers for head-neck angle (ICC = .562; 95% CI: -.28 to .809) and excellent agreement for humeral version (ICC = .962;.913 to .983). Although only fair agreement was found between observers in head-neck angle ICC, the difference in mean angle was only 2°. Discussion. Although much time and effort has been spent understanding and managing Type B2 glenoids, little attention has been paid to investigating associated humeral contributions to the Type B shoulder. Our results indicate that the humeral retroversion in Type B shoulders is significantly lower than in normals. These findings have several implications, including, helping to understanding the etiology of the B2, the unknown effects of arbitrarily selecting higher version angles for the humeral component, and the unknown effects of altered version on glenohumeral joint stability, loading and implant survivorship post-arthroplasty. Our results also raise an important question, whether it is best to reconstruct Type B humeral component version to pathologic version or to non-pathologic population means

Standard fixation for intra-articular distal humerus fracture is open reduction and internal fixation (ORIF). However, high energy fractures of the distal humerus are often accompanied with soft tissue injuries and or vascular injuries which limits the use of internal fixation. In our report, we describe a highly complex distal humerus fracture that showed promising healing via a ring external fixator. A 26-year-old man sustained a Gustillo Anderson Grade IIIB intra-articular distal humerus fracture of the non-dominant limb with bone loss at the lateral column. The injury was managed with aggressive wound debridement and cross elbow stabilization via a hinged ring external fixator. Post operative wound managed with foam dressing. Post-operatively, early controlled mobilization of elbow commenced. Fracture union achieved by 9 weeks and frame removed once fracture united. No surgical site infection or non-union observed throughout follow up. At 2 years follow up, flexion - extension of elbow is 20°- 100°, forearm supination 65°, forearm pronation 60° with no significant valgus or varus deformity. The extent of normal anatomic restoration in elbow fracture fixation determines the quality of elbow function with most common complication being elbow stiffness. Ring fixator is a non-invasive external device which provides firm stabilization of fracture while allowing for adequate soft tissue management. It provides continuous axial micro-movements in the frame which promotes callus formation while avoiding translation or angulation between the fragments. In appropriate frame design, they allow for early rehabilitation of joint where normal range of motion can be allowed in controlled manner immediately post-fixation. Functional outcome of elbow fracture from ring external fixation is comparable to ORIF due to better rehabilitation and lower complications. Ring external fixator in our patient achieved acceptable functional outcome and fracture alignment meanwhile the fracture was not complicated with common complications seen in ORIF. In conclusion, ring external fixator is as effective as ORIF in treating complex distal humeral fractures and should be considered for definitive fixation in such fractures

Abstract. Introduction. Intra-articular distal humerus OTA type C fractures are challenging to treat. When osteosynthesis is not feasible one can choose to do a primary arthroplasty of elbow or manage non-operatively. The indications for treatment of this fracture pattern are evolving. Objectives. We present our outcomes and complications when this cohort of patients was managed with either open reduction internal fixator (ORIF), elbow arthroplasty or non-operatively. Methods. Retrospective study to include OTA type C2 and C3 fracture distal humerus of 36 patients over the age of 50 years managed with all the three modalities. Patient's clinical notes and radiographs were reviewed. Results. Between 2016 and 2022, 21 patients underwent ORIF – group 1, 10 patients were treated with arthroplasty – group 2 and 5 were managed conservatively- group 3. The mean age of patients was 62 years in group 1, 70 years in group 2 and 76 years in group 3. The mean range of movement (ROM) arc achieved in the group 1 & 2 was 103 while group 3 was 68. At least follow up was 6 months. 5 patients in group 1 underwent metalwork removal and 2 patients in group 3 under arthroplasty. Conclusion. The outcomes of arthroplasty and ORIF are comparable, but reoperation rates and stiffness were higher in ORIF and conservative group. Surgeon choice and patient factors play important role in decision towards choosing treatment modality. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Abstract. Reverse shoulder arthroplasty (RSA) is being increasingly used for complex, displaced fractures of the proximal humerus. The main goal of the current study was to evaluate the functional and radiographic results after primary RSA of three or four-part fractures of the proximal humerus in elderly patients. Between 2012 and 2020, 70 consecutive patients with a recent three- or four-part fracture of the proximal humerus were treated with an RSA. There were 41 women and 29 men, with a mean age of 76 years. The dominant arm was involved in 42 patients (60%). All surgeries were carried out within 21 days. Displaced three-part fracture sustained in 16 patients, 24 had fracture dislocation and 30 sustained a four-part fracture of the proximal humerus. Patients were followed up for a mean of 26 months. The mean postoperative OSS at the end of the follow-up period was 32.4. The mean DASH score was 44.3. Tuberosity non-union occurred in 18 patients (12.6%), malunion in 7 patients (4.9%), heterotopic ossification in 4 patients (2.8%) and scapular notching in one patient. Anatomical reconstruction was achieved in 25 patients (17.5%), the influence of greater tuberosity healing on shoulder function could not be demonstrated. Heterotopic ossification seems to affect OSS and QDASH, we found statistically significant relation between HO and clinical outcomes. Patients with heterotopic ossification had significantly lower postoperative scores on DASH and OSS (P = .0527). Despite expecting good functional outcome with low complication rate after RSA, the functional outcome was irrespective of healing of the tuberosities

The aim of this study was to compare the results of humerus intramedullary nail(IMN) and dynamic compression plate(DCP) for the management of diaphyseal fractures of humerus. Material & Methods: 47 patients with diaphyseal fracture of shaft humerus were randomised prospectively and treated by open reduction and internal fixation with IMN or DCP. The criteria for inclusion was Grade 1,2a compound fractures Polytrauma Early failure of conservative treatment Unstable fracture. The patient with pathological fracture, Grade 3 open fracture, refracture, old neglected fracture of humerus were excluded from the study. 23 patients underwent internal fixation by IMN and 24 by DCP. Reamed antegrade nailing was done in all cases. DCP was done through an anterolateral or posterior approach. Results: The outcome was assessed in terms of functional outcome and the incidence of complications. Functional outcome was assessed using the Americans Shoulder and Elbow Surgeons Score (ASES).On comparing the results, there was no significant difference in ASES score between the two groups. The rate of complications was found to be higher in patients treated with IMN(p< .05). The complications that were encountered with IMN were non union, shortening of the arm,impingement of the shoulder, implant failure. The rate of secondary surgery was also found to be significantly higher with IMN(p< .05). Conclusion: There is sufficient evidence to suggest that DCP still remains to be the operative treatment of choice for diaphyseal fractures of humerus as use of IMN is associated with long learning curve, technical difficulties and higher complication rate. IMN may be indicated in specific situations like segmental fractures,pathological fratures though this study did not aim to look into that aspect

Aim. The aim of this study was to compare the results of humerus intramedullary nail (IMN) and dynamic compression plate (DCP) for the management of diaphyseal fractures of humerus. Material & methods. 47 patients with diaphyseal fracture of shaft humerus were randomised prospectively and treated by open reduction and internal fixation with IMN or DCP. The criteria for inclusion were Grade 1.2a compound fractures; Polytrauma; Early failure of conservative treatment; Unstable fracture. Patients with pathological fracture, Grade 3 open fracture, refracture or old neglected fracture of humerus were excluded from the study. 23 patients underwent internal fixation by IMN and 24 by DCP. Reamed antegrade nailing was done in all cases. DCP was done through an anterolateral or posterior approach. Results. The outcome was assessed in terms of union time, union rate, functional outcome and incidence of complications. Functional outcome was assessed using the American Shoulder and Elbow Surgeons Score (ASES). On comparing the results by independent samples t test, there was no significant difference in ASES score between the two groups. The average union time was found to be significantly lower for IMN compared to DCP(P<.05). The union rate was found to be similar in both the groups. Complications like infection were found to be higher with DCP compared to IMN, while shortening of the arm (1.5-4cm) and restriction of shoulder movements due to impingement of the nail were found to be higher with DCP compared with IMN. However, this improved in all patients following removal of the nail once the fracture healed. Conclusion. This study proves that IMN can be considerd as a better surgical option for these fractures as it offers shorter union time and less incidence of serious complications like infection. However, there appears to be no difference between two groups in union rate and functional outcome

The aim of this study was to compare the results of humerus intramedullary nail(IMN) and dynamic compression plate DCP) for the management of diaphyseal fractures of humerus. Material & Methods- 47 patients with diaphyseal fracture of shaft humerus were randomised prospectively and treated by open reduction and internal fixation with IMN or DCP. The criteria for inclusion was Grade 1,2a compound fractures, polytrauma, early failure of conservative treatment, unstable fracture. The patient with pathological fracture, Grade 3 open fracture, refracture, old neglected fracture of humerus were excluded from the study. 23 patients underwent internal fixation by IMN and 24 by DCP. Reamed antegrade nailing was done in all cases. DCP was done through an anterolateral or posterior approach. Results -The outcome was assessed in terms of functional outcome and the incidence of complications. Functional outcome was assessed using the Americans Shoulder and Elbow Surgeons Score (ASES). On comparing the results, there was no significant difference in ASES score between the two groups. The rate of complications was found to be higher in patients treated with IMN than with DCP. The complications that were encountered with IMN were non union, shortening of the arm, impingement of the shoulder, implant failure. The rate of secondary surgery was also found to be significantly higher with IMN. Conclusion – There is sufficient evidence to suggest that DCP still remains to be the operative treatment of choice for diaphyseal fractures of humerus. IMN may be indicated only in specific situations like segmental fractures, pathological fratures though this study did not aim to look into that aspect

Objectives. The goal of this study is to investigate the relation between indicators of osteoporosis (i.e., bone mineral density (BMD), and Cortical Index (CI)) and the complexity of a fracture of the proximal humerus as a result of a low-energy trauma. Methods. A retrospective chart review of 168 patients (mean age 67.2 years, range 51 to 88.7) with a fracture of the proximal humerus between 2007 and 2011, whose BMD was assessed at the Fracture Liaison Service with Dual Energy X-ray Absorptiometry (DXA) measurements of the hip, femoral neck (FN) and/or lumbar spine (LS), and whose CI and complexity of fracture were assessed on plain anteroposterior radiographs of the proximal humerus. Results. No significant differences were found between simple and complex fractures of the proximal humerus in the BMD of the hip, FN or LS (all p > 0.3) or in the CI (p = 0.14). Only the body mass index was significantly higher in patients with a complex fracture compared with those with a simple fracture (26.9 vs 25.2; p = 0.05). Conclusion. There was no difference in BMD of the hip, FN, LS or CI of the proximal humerus in simple compared with complex fractures of the proximal humerus after a low-energy trauma. Factors other than the BMD and CI, for example body mass index, may play a more important role in the complexity of this fracture. Cite this article: J.W.A.M. den Teuling, B.S. Pauwels, L. Janssen, C.E. Wyers, H. M. J. Janzing, J.P.W. van den Bergh, J. W. Morrenhof. The Influence of bone mineral density and cortical index on the complexity of fractures of the proximal humerus. Bone Joint Res 2017;6:584–589. DOI: 10.1302/2046-3758.610.BJR-2017-0080

Abstract. Background. Fractures Proximal humerus account for nearly 10 % of geriatric fractures. The treatment options varies. There is no consensus regarding the optimal treatment, with almost all modalities giving functionally poor outcomes. Hence literature recommends conservative management over surgical options. MULTILOC nail with its design seems to be a promising tool in treating these fractures. We hereby report our early experience in the treatment of 37 elderly patients. Objectives. To evaluate the radiological outcome with regards to union, collapse, screw back out/cut through, implant failures, Greater tuberosity migration. To evaluate the functional outcome at the end of 6 months using Constant score. Study Design & Methods. All patients aged >65 years who underwent surgery for 3,4-part fracture proximal humerus using the MULTILOC nail were included in the study after consent. Pre – existing rotator cuff disease were excluded. Within the time frame, a total of 39 patients underwent the said surgery. 2 patients were lost to follow up. All the measurements were taken at the end of 6 months and results tabulated and analysed. Results. Union was achieved in all the 37 patients. There were no varus collapse or screw backout/cut through seen in any of the patients. There was Greater tuberosity migration in 1 patient who underwent revision surgery at 6 weeks. All the patients got a minimum of 70 degrees of abduction and forward flexion. We had 29 excellent, 6 good, 2 fair and none poor results as per Constant scoring system. Study done in Tejasvini Hospital & SSIOT Mangaluru India

Aims: The purpose of our study is to evaluate the results of the treatment of unstable upper humerus fractures with the implantation of the Plant-Tan Plate which is a combination of an internal fixator with a neutralization plate. Methods: In a period of 17 months (January2001–May2002), 10 fractures in 10 patients (7female – 3 male) were treated. Their ages ranged from 45 to 75 years (mean 67.8 years). Patients with unstable fractures (two to four according to Neer’s classification are include in the study. The Plant-Tan Plate was used. Two head screws were placed in all fractures. The follow-up ranged from 4 to 21 months (mean 14.5months). The ASES scoring system was used to evaluate the results. Results: All our patients achieved clinical and radiological union of the fractures in a period of 4 months. The average cumulative score of activities of daily living of ASES Scoring System was 23 out of 30 (76.66%). One superficial wound infection occurred which was resolved with the administration of antibiotics. Conclusions: The Plant-Tan Plate rapresents a new, promising method of internal fixation for fractures of the proximal humerus, which offers anatomical reduction and a stable osteosynthesis (provding angular and rotational stability), so that an early rehabilitation program can be instituted

Patients and Methods: Between December 2005 until January 2008 34 distal humerus fractures in 33 patients were prospectively documented and treated using the angular-stable LCP distal humerus plate system from Synthes/Switzerland. Patient median age was 54 (min 14/ max 88). Fracture types were classified according to the AO classification. Extraarticular A fractures were documented in 3 (9%) cases, partial intra-articular fractures (type B) were seen in 4 (12%) patients. Complete intraarticular fractures were found in 27 (79%) cases. Three fractures were grade I° open, 6 fractures were grade II° open according to the Gustilo classification. In median after 10 months (min 8/ max 20) follow up was performed. Due to lost to follow up in one patient functional outcome was measured in 32 patients. Functional results were evaluated using the Mayo Elbow Performence Score (MEPS). Results: According to MEPS, predominantly excellent and good results were achieved. The intent of stable fracture fixation to allow early physical therapy was reached in 31 patients. Failure of osteosynthesis making operative revision necessary occurred in 3 patients (1x implant failure, 2x loss of reduction). Mean Mayo Elbow Performance Score was 91 points (min 88.5/ max 100). Mean range of motion for extension/flexion was 110° (min 80/ max 140) and 170° (min 125/max 180) for pronation/supination. Only one patient regained unrestricted extension, mean loss of extension was 21° (min 10/ max 40). Mean Flexion up to 131° was achieved (min 125/ max 140). Postoperative complications were seen in eight cases (implant breakage, delayed union, lost of reduction). Conclusion: Despite postoperative complications and revision surgery, functional results achieved using the angular-stable LCP distal Humerus system are good or excellent in the majority of patients. Through angular-stable and multidirectional screw options fixation of the distal fragment is sufficient and periostal blood supply could be protected. Especially in combination of intraarticular fractures and osteoporotic bone stock the use of the LCP distal Humerus plate system is suitable and permits early physical therapy, promising a benefit for the elbow function

Advancements in treating distal humerus fractures. We will review and discuss approaches to the elbow to treat different types of fractures. We will discuss the role of soft tissue structures and how they affect elbow function. During this session, we will review the latest techniques for treating the complex articular fractures of the distal humerus to include capitellar and trochlear fractures. Techniques presented will address fixation, reconstruction, and salvaging of complex distal humerus fractures

The morphology of the proximal part of the humerus varies largely. Morphometric features characterizing the three-dimensional geometry of the proximal humerus have revealed a wide difference within individuals. These parameters include head size, radius of curvature, inclination angle, retroversion angle, offsets and neck-shaft angle. Different implant designs have been adapted so as to make provision for these anatomical variations. However, the optimal design criteria are yet to be established. Implant design is one of the main factors determining the success of Total Shoulder Arthroplasty (TSA) since slight modifications in the implant anatomy could have significant biomechanical effects. Therefore, this study investigates the three-dimensional morphometric parameters of the South African proximal humerus which will serve as a basis for designing a new Total Shoulder Prosthesis for the South African population. Sixteen South African (SA) fresh cadaveric humeri (8 left, 8 right; 8 paired) were used in this study. The data consisted of 6 men and 2 women with ages ranging from 32 to 55 years (43.13 ±8.51). The humeri were scanned using a Computer Tomography (CT) scanner. The Digital Imaging and Communications in Medicine (DICOM) files from the CT data were imported into medical modelling software, MIMICS for reconstruction. The 3D reconstructed model of the humeri as an STL file was used for further processing. The STL data were generated as a cloud of points in a CAD software, SolidWorks. These were then remodeled by defining the detailed Referential Geometric Entities (RGEs) describing the anatomical characteristics. Anatomical reference points were defined for the anatomical neck plane, the epiphyseal sphere and the metaphyseal cylinder. Also, axes were defined which comprises of the humeral head axis and the metaphyseal axis. Thereafter, the posterior offsets medial offsets and the inclination angles were measured based on the RGEs. The posterior offset varied from 0.07 mm to 2.87 mm (mean 1.20 mm), the medial offset varied from 4.40 mm to 8.45 mm (mean 6.50 mm) while the inclination angle varied from 114.00º to 133.87º (mean 121.05º). The outcome of the study showed that the shape and dimensions of the proximal humerus varies distinctively. The articular surface is not a perfect sphere and differs independently with respect to the inclination angles. In addition, variations were noticeable in the medial and lateral offsets. The morphometric data on the African shoulder is very limited and this study will significantly contribute to the shoulder data repository for the SA population. The morphometric parameters measured in this study will be useful in designing a South African shoulder prosthesis that mimics the native shoulder hence eliminating post-surgical complications

Abstract. Objectives. Operative management of distal humerus fractures is challenging. In the past, plates were manually contoured intraoperatively, however this was associated with high rates of fixation failure, nonunion and metalwork removal. Anatomically pre-contoured distal humerus locking plates have since been developed. Owing to the rarity of distal humeral fractures, literature regarding outcomes of anatomically pre-contoured locking plates is lacking and patient numbers are often small. The purpose of this study is to investigate the outcomes of these patients. Methods. We retrospectively identified patients with distal humeral fractures treated at our institution from 2009–2018. Inclusion criteria were patients with a distal humeral fracture, who underwent two-column plate fixation with anatomically pre-contoured locking plates. Clinical records and radiographs were reviewed to elicit outcome measures, including range of motion, complications and reoperation rate. Results. We identified 50 patients with mean age of 55 years (range 17–96 years). Mean length of follow up was 5.2 years. AO fracture classification Type A occurred most frequently (46%), followed by Type B (22%) and Type C (32%). Low energy mechanisms of injury predominated in 72% of patients. Mean time from injury to fixation was seven days. Mean range of motion at the elbow was 13–123o postoperatively. The overall reoperation rate was 22%, the majority of which required subsequent removal of prominent metalwork (18%). The incidence of nonunion, heterotopic ossification, deep infection and neuropathy requiring decompression was 2% each. Fixation failure occurred in only one patient however the fracture went on to heal. Conclusions. Previously reported reoperation rates with manually contoured plates were as high as 44%, which is twice our reported rate. Modern locking plates are no longer subject to implant failure (previously 27% reported metalwork failure rate). Likewise, heterotopic ossification and non-union have also reduced, highlighting that modern plates have significantly improved overall patient outcomes. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Introduction. Stress shielding of bone around the stem components of total shoulder replacement (TSR) implants can result in bone resorption, leading to loosening and failure. Titanium is an ideal biomaterial for implant stems; however, it is much stiffer than bone. Recent advances in additive manufacturing (AM) have enabled the production of parts with complex geometries from titanium alloys, such as hollow or porous stems. The objective of this computational study is to determine if hollow titanium stems can reduce stress shielding at the proximal humerus. We hypothesize that hollow TSR implant stems will reduce stress shielding in comparison with solid stems and the inner wall thickness of the hollow stem will be a design parameter with a direct effect on bone stresses. Methods. Using a previously developed statistical shape and density model (SSDM) of the humerus based on 75 cadaveric shoulders, a simulated average CT image was created. Using MITK-GEM, the cortical and trabecular bones were segmented from this CT image and meshed with quadratic tetrahedral elements. Trabecular bone was modeled as an isotropic and inhomogeneous material, with the Young's modulus defined element-by-element based on the corresponding CT densities. Cortical bone was assumed isotropic with a uniform Young's modulus of 20 GPa. The Poisson's ratio for all bone was 0.3. The distal humerus was fully constrained. Bone stresses were calculated by performing finite element analyses in ABAQUS with a 320 N force and 2 Nm frictional moment applied to the articular surface of the humeral head, based on an in vivo study during 45 degrees of shoulder abduction. Subsequently, the humeral head was resected and reamed to receive solid- and hollow-stemmed implants with identical external geometries but three different inner wall thicknesses (Figure 1). The identical surrounding bone meshes for the intact and reconstructed bones allowed element-by-element stress comparisons. The volume-weighted average changes in cortical and trabecular bone von Mises stresses were calculated, (wrt the intact humerus), as well as the percentage of bone volume experiencing a relative increase or decrease in stress greater than 10%. Results. Results for all four implant designs are summarized (Figure 2). The solid stem resulted in the biggest average change in von Mises stresses (4% decrease in cortical and 6% increase in cancellous bone stress). The solid stem also resulted in the largest volume of bone experiencing a decrease in stress. Comparing the hollow stems, the thinnest shell wall resulted in the smallest changes in cortical bone stress, and the lowest volumes of bone experiencing a decrease in stress. Interestingly, this design caused the most cancellous bone to experience an increase in stress. Discussion. These results suggest a marginal improvement in the bone-implant mechanics of hollow versus solid stems, and that thinner shell walls perform better. That said, the improvements over the solid stem design are minimal. Further increasing the compliance of these stems, e.g. by adding pores, may improve their performance. Future work will focus on optimizing hollow and porous stem designs, and the possibility of leveraging their hollow design for drug delivery. For any figures or tables, please contact the authors directly