Objectives. Distal humerus fractures in elderly population are often comminuted and presents multiple challenges. When managed with fixation the results are often complicated with stiffness, pain, and reduced function while total elbow replacement is fraught with lifelong restrictions on load bearing which can significantly affect elderly patients who rely assistive devices for ambulation. Elbow hemiarthroplasty however, presents a viable alternative in these cases. This series evaluates the results of the distal humerus hemiarthroplasty in a single centre. Designs and methods. Data was collected retrospectively. Comprehensive case reviews were done to collect demographic, intra-operative and post-operative data. Fractures were classified as per AO classification. The primary outcome was functional outcome and range of motion (ROM). The secondary outcomes were complications and patient satisfaction. Results. 22 cases were included in this study from 2016 – 2023 majority being females (n=18). Mean age was 74years (SD −11.2). Majority fractures were AO type C3 (n=15) with two A2 type fractures managed for non-union. Pre-existing bone on bone arthritis was present in 3 cases and CT scan was done for 12 patients to assess fracture configuration. Excluding those treated for non- union the median time between fracture and surgery was 8.5 days. Follow-up of more than 6 months was available for 16 patients with median follow-up of 18 months. ROM was available for 17 patients with 13 (50%) patients having functional ROM. No patients had full extension and there was a mean lag of 20. 0. Mean flexion was 118.2. 0. Nearly 2/3. rd. patients (73%- n=16) were satisfied with the surgery with no problems in activity of daily living. Complications seen were ulnar neuropathy (n=3), heterotopic ossification(n=2) and periprosthetic fracture (n=1). Conclusion. This single centre study suggests good outcomes following distal humerus hemiarthroplasty. It is a reasonable alternative to fixation and total elbow arthroplasty in complex 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

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

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

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

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

Introduction:. Distal humerus fractures as well as elbow fracture dislocation are often accompanied by soft tissue damage that warrants early fixation with an external fixator. The distal humerus is a hazardous area for placement of an external fixator due to the close proximity of the radial nerve to the humerus in this area. No known safe zone has been identified on the lateral border of the humerus to avoid radial nerve damage. The aim of this study was to record the incidence of radial nerve damage by placing two 4 mm pins into the humerus and to note the relation of the nerve to the pins. Methods:. Two 4 mm pins used to fix an external fixator were drilled into the lateral border of the humerus at points 100 mm and 70 mm proximal to the lateral epicondyle of both arms of 39 cadavers. The 30 mm interval between the pins is the interval between the pins in a pinblock of a commonly-used external fixator. The arms were dissected by medical students and the incidence of radial nerve damage was recorded. Statistical analysis was done using a Fischer's exact test to identify the incidence of nerve damage relative to pin insertion. The number of damaged nerves was compared to the number of non-damaged nerves. A design based Chi Square test was carried out to test left and right arms. The proportions of interest were estimated along a 95% confidence interval. Results:. The radial nerve was hit (damaged) by 56.4% of the proximal and 20.5% of the distal pins. The radial nerve ran posterior to the proximal pin in 2.57% of arms and 0% to the distal pin. Conclusion:. Although no clear safe zone could be established, pins should be placed closer than 100 mm from the lateral epicondyle and as posterior on the humerus as possible to minimize the risk for radial nerve damage. Keywords: Radial nerve, external fixation, humerus fractures

The distal humerus represents 1% of all primary bone tumours. Endoprosthetic replacement can potentially improve function and provide good pain relief. We present out experience with the custom made Stanmore elbow endoprosthesis used after resection of malignant tumours of the distal humerus. Between 1970–2009 we carried out 19 endoprosthetic replacments for malignant tumours of the distal humerus. 10 were a result of metastasis and 9 were primary bone tumours. 7 patients had a pathological fracture as their first presentation and 3 had pathological fractures after the diagnosis was made. 11 patients died between 3 months to 16 year following surgery. The mean survival of the patient group was 7.1 years (range 3 months to 37 years). 4 patients underwent a revision EPR and one patient underwent two revision EPR's due to loosening. Two patients underwent maintenance procedures (rebushing) due to wear of the poly bushing. We have had no revisions since the design of hte implant was changed to a floppy hinge design. One patient underwent an above elbow amputation four years after surgery due to local recurrence. There were no early post operative infections. One patient developed a sinus requiring multiple wound explorations, one year after insertion of the endoprosthesis for a sarcoma. This patient was infection free till the time of death 3 years later. There were no nerve palsies, periprosthetic fractures or wound problems. The mean TES score was 72% (59–78%) in the surviving patients at review. As the majority of the patients were implanted for metastatic disease the initial reliablity and low complication rate of the procedure, in our series, confirms that this is a suitable reconstruction for patients in significant metastatic pain from a destructive lesion of the distal humerus, rapidly restoring function and relieving pain in a predictable manner

We report the case of a 12-year-old boy with flexion loss in the left elbow caused by deficient of the concavity corresponding to the coronoid fossa in the distal humerus. The range of motion (ROM) was 15°/100°, and pain was induced by passive terminal flexion. Plain radiographs revealed complete epiphyseal closure, and computed tomography (CT) revealed a flat anterior surface of the distal humerus; the coronoid fossa was absent. Then, the bony morphometric contour was surgically recreated using a navigation system and a three-dimensional elbow joint model. A three-dimensional model of the elbow joint was made preoperatively and the model comprising the distal humerus was milled so that elbow flexion flexion of more than 140° could be achieved against the proximal ulna and radius. Navigation-assisted surgery (contouring arthroplasty) was performed using CT data from this milled three-dimensional model. Subsequently, an intraoperative passive elbow flexion of 135° was obtained. However, active elbow flexion was still inadequate one year after operation, and a triceps lengthening procedure was performed. At the final follow-up one year after triceps lengthening, a considerable improvement in flexion was observed with a ROM of −12°/125°. Plain radiographs revealed no signs of degenerative change, and CT revealed the formation of the radial and coronoid fossae on the anterior surface of the distal humerus. Navigation-assisted surgery for deformity of the distal humerus based on a contoured three-dimensional model is extremely effective as it facilitates evaluation of the bony morphometry of the distal humerus. It is particularly useful as an indicator for milling the actual bone when a model of the mirror image of the unaffected side cannot be applied to the affected side as observed in our case

Introduction. Treatment for distal third shaft fractures of humerus is very challenging. They are commonly treated with plating. Plating has complications of iatrogenic radial nerve palsy. We report our case series of distal third fractures of humerus treated with retrograde Halder Humeral Nail. Materials/Methods. Since 1994 to 2010 we have 576 fractures of humerus treated with retrograde Halder Humeral nail. Of these 45 fractures were distal third of humerus. Average age of patients at the time of surgery was 30.4 years (Range 15–82 years, Median 33 years). Of 45 patients 26 were females and 19 males. Three out of 45 had non union at the time of presentation. All patients were followed until clinical and radiological signs of union. One patient was lost to follow-up. Results. Average time to fracture healing was 13.9 weeks (Range 9–36 weeks). There were two cases of non union, one healed at 9 months with 2. nd. surgery. There was one reported case of infection. Seven patients had nail removal electively. All the patients achieved full range of elbow and shoulder movement. No reported cases of iatrogenic radial nerve palsy. Conclusion. Our results of distal third fractures of humerus treated with retrograde Halder Humeral Nail are excellent. It avoids big exposure as needed in plating and complication of iatrogenic radial nerve palsy

The humeral component has a long track record of a low rate of humeral loosening. Moreover, there are significant challenges associated with removal of a failed cemented component. Throckmorton reviewed the results of 76 total shoulder arthroplasties for osteoarthritis with minimum two year follow-up. There were incomplete lucent lines in 5/76 stems. None of the stem were judged to be at risk for loosening. Matsen published on the outcome of 131 shoulder arthroplasties for osteoarthritis with minimum two year follow-up. In this series, there were no components with shift or tilt. In addition to strong literature support for the use of an uncemented humeral component, revision of a cemented humeral component can be very difficult with a risk of significant destruction of the humerus. The cortex of the humerus tends to be thin and removing the cement can be similar to trying to remove concrete from an ice cream cone. Therefore, the extremely low rate of loosening and the challenges associated with cemented components makes the non-cemented component the ideal humeral solution

Humerus non-unions are difficult to treat, especially those with infected non-unions, bone loss, deformity, previous multiple surgeries and/or broken hardware. This paper presents our experience with the use of the Ilizarov frame with humerus non- unions. Eight consecutive humerus non-unions were treated using the Ilizarov frame. Only loose or infected hardware was removed. The Ilizarov frame was applied using safe zones principles of Ilizarov, Catagni and Paley. Aspetic non-unions were treated with deformity correction, sequential compression and distraction, bone grafting and intramedullary stabilisation for diaphyseal nonunions. Infected diaphyseal non-unions were treated intra-medullary reaming with or without excision of infected necrotic bone segment, followed by insertion of antibiotic cement rod and compression. Elbow spanning frames were avoided for supracondylar non-unions. Fine wire fixation of the distal fragment was preferred instead. Free elbow movement was allowed. There were two infected (diaphyseal) and six aseptic non-unions (four diaphyseal and two supracondylar) treated with this technique. Broken hardware was left in-situ in five cases. The average time from the index injury was 14 months, with each case having had an average of 3.2 procedures, prior to the application of the Ilizarov frame. Union was obtained in all cases. The average humerus shortening was 1.5 cm. There was no residual angular or rotational deformity. Infection was eliminated in both the infected non-unions. Primary bone grafting was used in all aseptic nonunions. Additional bone grafting was needed as a secondary procedure in four cases prior to frame removal. T he average time spent in the frame was 4.5 months. The Ilizarov method is a useful option for the management of complex humerus non-unions. Patients learn to tolerate the fixator and can achieve functional shoulder and elbow range with the fixator

Introduction. Pathologic humerus fractures secondary to metastases are associated with significant pain, morbidity, loss of function, and diminished quality of life. Here we report our experience with stabilisation using intramedullary polymethylmethacrylate (PMMA) cement and non-locking plates. Methods. A retrospective review was undertaken of patients treated at a tertiary musculoskeletal oncology centre from 1989 to 2009. Patients who underwent surgery for an impending or completed pathologic humerus fracture with a diagnosis of metastatic disease or myeloma were included. All patients underwent intralesional curettage of the tumour followed by fixation with intramedullary PMMA and plating. Results. Clinical records were available for 63 patients who underwent the above procedure. There were 43 males and 20 females. In 48 (76%) there was a pathologic fracture at presentation, while in 15 (24%) it was impending. The most common histology was myeloma (22%) followed by lung and renal carcinoma which were 21% each. Complications occurred in 14 (22%) cases, and 7 (11%) required re-operation. The most common cause for re-operation was disease progression (5 of 7). At latest follow-up, 85% had no or mild pain and 80% required no or minimal assistance with activities of daily life (ADLs). Conclusion. Intralesional tumour resection and stabilisation of pathologic humerus fractures with the described technique has several attributes. It provides immediate, absolute rigidity and enables early pain relief and return of function without the need for osseous union. The patient's local disease burden is reduced, which alleviates tumour-related pain and slows disease progression. Finally, this technique is user-friendly and cost-effective as it does not require equipment or devices that are unavailable to community orthopaedic surgeons. The cemented plate technique provides a durable option for the treatment of impending and completed pathologic humerus fractures

Aim. Treatment for distal third shaft fractures of humerus is very challenging especially if its comminuted and bone is osteopenic. They are commonly treated with plating. Plating has complications of iatrogenic radial nerve palsy. We report our case series of distal third fractures of humerus treated with retrograde Halder Humeral Nail. Materials and methods. Since 1994 to 2010 we have 576 fractures of humerus treated with retrograde Halder Humeral nail. Of these 45 were distal third extra articular fractures of humerus. Average age of patients at the time of surgery was 30.4 years (Range 15–82 years, Median 33 years). Of 45 patients 26 were females and 19 males.3 out of 45 had non union at the time of presentation. The nail was locked distally with one or two screws and proximally with a screw and tripwire. The entry point of the nail was roof of olecranon fossa (contrary to standard retrograde nails where it is an inch above olecranon fossa) This design of nail allows it be used for even very distal fractures. All patients were followed till clinical and radiological signs of union. 1 patient was lost to follow up. Results. Average time to fracture healing was 13.9 weeks (Range 9–36 weeks). There were 2 cases of non union, one healed at 9 months with 2. nd. surgery. The other non union was asymptomatic and did not agree for further surgery. There was one reported case of infection.7 patients had nail removal electively on request. All the patients achieved full range of elbow and shoulder movement. No reported cases of iatrogenic radial nerve palsy. Conclusion. Our results of distal third fractures of humerus treated with retrograde Halder Humeral Nail are excellent. It avoids big exposure as needed in plating and complication of iatrogenic radial nerve palsy

INTRODUCTION. Over the last twenty years, image-guided interventions have been greatly expanded by the advances in medical imaging and computing power. A key step for any image-guided intervention is to find the image-to-patient transformation matrix, which is the transformation matrix between the preoperative 3D model of patient anatomy and the real position of the patient in the operating room. In this work, we propose a robust registration algorithm to match ultrasound (US) images with preoperative Magnetic Resonance (MR) images of the Humerus. MATERIALS AND METHODS. The fusion of preoperative MR images with intra-operative US images is performed through an NDI Spectra® Polaris system and a L12-5L60N TELEMED® ultrasound transducer. The use of an ultrasound probe requires a calibration procedure in order to determine the transformation between an US image pixel and its position according to a global reference system. After the calibration step, the patient anatomy is scanned with US probe. US images are segmented in real time in order to extract the desired bone contour. The use of an optical measurement system together with trackers and the previously-computed calibration matrix makes it possible to assign a world coordinate position to any pixel of the 2D US image. As a result, the set of US pixels extracted from the images results in a cloud of 3D points which will be registered with the 3D Humerus model reconstructed from MR images. The proposed registration method is composed of two steps. The first step consists of US 3D points cloud alignment with the 3D bone model. Then, the second step performs the widely-known Iterative Closest Point (ICP) algorithm. In order to perform this, we define the coordinate system of both the 3D Humerus model and the US points cloud. The frame directions correspond to the directions of the principal axes of inertia calculated from the matrices of inertia of both the preoperative 3D model and the US data obtained intra-operatively. Then, we compute the rotation matrix to estimate the transformation between the two coordinate systems previously calculated. Finally the translation is determined by evaluating the distance between the mass centres of the two 3D surfaces. RESULTS. In order to evaluate the performance of this registration method in terms of precision and accuracy, we performed the US/MRI fusion on 8 patients. The evaluation criterion used for the validation step was the fiducial registration error (FRE) estimation based on 8 anatomic fiducials detected on the Humerus of the patient. The mean, standard deviation, minimum and maximum values of the 8 Fiducial Registration Errors were 4.34, 2.20, 2.81 and 9.48 mm, respectively. DISCUSSIONS. In this work, we propose a robust registration method of MR and US data. Thanks to the optical system, this fusion will allow us for example to guide and assist surgeons in the positioning of the radiofrequency probe for bone tumor ablation. In addition to the fact that it is completely automatic, the proposed image-to-patient registration method is minimally invasive

Introduction. Proximal humeral fracture occurs most frequently in elderly and usually unite within 12 weeks. Malunion is more common than nonunion. And even if nonunion occurs, we usually treat it by the blade plate. Norris et al. reported hemiarthroplasty is indicated for severe degenerative changes of the articular surface, osteonecrosis of the humeral head, or osteopenia severe enough to jeopardize fixation in order patients. Therefore, it is not common that hemiarthroplasty is used for primary treatment of the proximal humeral pseudoarthrosis. We report a case of proximal humerus pseudoarthrosis which was treated by hemiarthroplasty. Case. A patients is 75 years old male. He was injured by falling from ladder. He was diagnosed proximal humeral fracture Neer type2. After he was followed conservatively for one year, he was referred to our hospital. In X-ray film and CT, the humeral head was scraped by the humeral shaft that was tucked inward to humeral head.(Figure 1) In MRI, rotator cuff muscles were left. The fatty infiltration was stage 1 in the Gourtallier classification. (Figure 2)And osteoarthritis of shoulder was not so severe. Therefore, we decided to do hemiarthroplasty. We used the SMR implant (Lima Corporate, Milano, Italy). Surgical reconstruction was done using a deltpectral approach. Lesser tuberosity was cut from greater tuberosity with subscaplaris muscle. We used the cementless stem. Each fragments and stem was fixed using FiberWire (Arthrex, Florida USA), after autograft which scraped from the reseceted humeral head was stuffed. After the operation, the shoulder was fixed by brace for 4weeks. The passive ROM exercise was started from 21 days later. The Active ROM exercise was started at 28 days later. Three months later, the pseudoarthrosis united successfully. (Figure 3) The active flexion was improved from 20 degrees to 110 degrees. The active abduction was from 20 degrees to 90 degrees. USLA score was improved from 10 to 26. Discussion. In this case, the pseudoarthrosis is united successfully. Therefore, the cementless hemiarthroplasty is useful for treatment for the proximal humerus pseudoarthrosis with severe humeral head bone defect

Minimally displaced paediatric proximal humerus fractures (PHFs) can be reliably managed non-operatively, however there is considerable debate regarding the appropriate management of severely displaced PHFs, particularly in older children and adolescents with limited remodelling potential. The purpose of this study was to perform a systematic review to answer the questions: “What are the functional and quality-of-life outcomes of paediatric PHFs?” and “What factors have been associated with a poorer outcome?”

A review of Medline and EMBASE was performed on 4^th July 2021 using search terms relevant to PHFs, surgery, non-operative management, paediatrics and outcomes. Studies including ≥10 paediatric patients with PHFs, which assessed clinical outcomes by use of an established outcome measure, were selected. The following clinical information was collected: participant characteristics, treatment, complications, and outcomes.

Twelve articles were selected, including four prospective cohort studies and eight retrospective cohort studies. Favourable outcome scores were found for patients with minimally displaced fractures, and for children aged less than ten years, irrespective of treatment methodology or grade of fracture displacement. Older age at injury and higher grade of fracture displacement were reported as risk factors for a poorer patient-reported outcome score.

An excellent functional outcome can be expected following non-operative management for minimally displaced paediatric PHFs. Prospective trials are required to establish a guideline for the management of severely displaced PHFs in children and adolescents according to fracture displacement and the degree of skeletal maturity.

Introduction. Fractures of the proximal humerus represent a major osteoporotic burden. Recent developments in CT imaging have emphasized the importance of cortical bone thickness distribution in the prevention and management of fragility fractures. We aimed to experimentally define the CT density of cortical bone in the proximal humerus for building cortical geometry maps. Methods. With ethical approval we used ten fresh frozen human proximal humeri. These were stripped of all soft tissue and high resolution CT images were then taken. The humeral heads were then subsequently resected to allow access to the metaphyseal area. Using curettes, cancellous bone was removed down to hard cortical bone. Another set of CT images of the reamed specimen was then taken. Using CT imaging software and a CAD interface we then compared cortical contours at different CT density thresholds to the reference inner cortical contour of our reamed specimens. Working with 3D model representations of these cortical maps, we were able to accurately make distance comparison analyses based on different CT thresholds. Results. We could compute a single closest value at 700HU. There was no difference found in the HU based contours generated along the 500HU–900HU pixels (p=1.000). The contours were significantly different to those generated at 300HU, 400HU, 1000HU and 1100HU. Discussion/conclusion: A Hounsfield range of 500 to 900 HU can accurately depict cortical bone geometry in the proximal humerus. Thresholding outside this range leads to statistically significant inaccuracies. Our results concur with a similar range reported in the literature for the proximal femur. Knowledge of regional variations in cortical bone thickness has direct implications for basic science studies on osteoporosis and its treatment, but is also important for the orthopaedic surgeon since our decision for treatment options is often guided by local bone quality

Supra-condylar humerus fractures (SCHF) are amongst the most common fractures requiring surgical stabilisation in the pediatric age group (1). Closed reduction and percutaneous fixation with Kirschner wires (KW) is currently the standard of care (2). The number of KW used and their configuration has been the subject of much research (3, 4). The failure modes leading to loss of fracture reduction are not clear and have not been quantified. The aim of this study is to compare the mechanical stability of the opt-used configurations for various loading modes and contact interactions at the KW/bone interface. A Gartland type-III SCHF was introduced to a fourth generation composite saw bone (Sawbones®, Vashon, Washington, USA). The model was CT scanned with a slice spacing of 0.5mm and pixel size 0.3×0.3mm. The CT data set was imported into AmiraDev (AmiraDev 5.2 Visage Imaging, Inc). A uniaxial mechanical test was conducted in order to measure the KW pullout forces from the distal humerus. A model of the fractured humerus was constructed with the following steps: 1) manual segmentation; 2) surface generation of each fragment, and; 3) automatic volumetric grid generation for each fragment. The fracture was then virtually reduced and KWs were placed at the desired configurations (Fig 1a-b). For each configuration, a separate model was generated. Material properties were assigned to the bone-model elements according to the manufacturer's data sheet; Young's modulus E = 16GPa and E = 150MPa for the cortical and cancellous bone respectively. The KW were assigned a Young's modulus of 200GPa. Each of the models created in Amira was imported to a finite element application (Abaqus 6.9, DS-Simula) for structural analysis. For each of KW configuration four different torque forces load types were simulated (Fig 1c left): 1) a clockwise and counterclockwise torque with a magnitude of 1.5 NM (Newton/Meters); 2) a translational force with a magnitude of 30 N (Newtons) in the direction of the humerus shaft, and; 3) a shear force with a magnitude of 30 N in the direction parallel to the fracture plane. The results were normalised such that the maximum displacement for the crossed pin configuration with a coefficient of friction equal to zero (μ = 0) was used as unity for each load configuration. Similarly, for each of KW configuration four different translational forces load types were simulated (Fig 1c right): 1) a clockwise and counter clock-wise torque with a magnitude of 1.5 NM (Newton/Meters); 2) a translational force with a magnitude of 30N in the direction of the humerus shaft, and; 3) a shear force with a magnitude of 30N in the direction parallel to the fracture plane. The results were normalised as described above. Results. Torque forces: the crossed configuration was found to be almost independent of the bone-implant friction and was symmetric in terms of direction of the applied torque. The diverging configuration exhibited larger dependency on the bone-implant interface. This is especially noticed as the coefficient of friction (COF) reduced to values below μ = 0.2. Translational forces: the diverging configuration exhibited high sensitivity to reduction of the COF μ = 0. Displacement of the fracture for μ = 0 was substantially larger for the diverging configuration relative to the crossed configuration: 13.5 times and 19 times for the transverse and pullout directions, respectively. As the COF increased to values above μ = 0.5, both fixation configurations performed in a similar manner. Stabilisation of SCHF has been the subject of numerous studies. Relative stability of the different configurations and the risk for iatrogenic ulnar nerve injury has been in the center of the debate. Crossed KW configuration was shown in some clinical studies to be more stable than two lateral KW while others demonstrated no significant difference in stability. As ulnar nerve injury may occur in up to 15.4% of surgeries even if insertion of a medial KW is performed under direct vision, utilisation of two lateral KW configurations offers the advantage of reducing this risk significantly. The main finding of this study is that for a COF exceeding a threshold level (µ = 0.2) the crossed KW configuration did not offer any mechanical advantage over the diverging lateral KW configuration. However, for very low COF values (µ<0.2) the crossed configuration exhibited improved performance when compared with divergent lateral KW (figure 1d). The data demonstrates that the KW-bone bonding has a profound effect on the stability of the fixated bone construct. This is mostly evident when distraction forces are applied but also occurs, to a lesser degree, with rotational or translational forces. This may be a clinically important consideration in the rare SCHF in children with abnormal bones and possibly more commonly, when the KW-bone bonding was compromised after multiple attempts of passing the KW through the same entry point. We have conducted a combined in-vitro mechanical test and finite element-based simulations of a fixated SCHF with different KW configurations, under various friction conditions. Under normal bone-implant interface bonding conditions, the two diverging lateral KW configuration offers adequate mechanical stability and may be the preferred choice of SCHF fixation