Introduction. This study aims to investigate the relationship between ulnar fixation and postoperative satisfaction among patients with distal radius fractures accompanied by ulna styloid fractures, with a particular focus on how sociodemographic factors influence outcomes. Method. A retrospective cohort study was conducted involving 120 patients aged 26-53 who underwent surgical treatment for distal radius fractures with concomitant ulna styloid fractures between January 2018 and December 2022. Patients were divided into two groups based on whether ulnar fixation was performed. Sociodemographic data, including age, gender, socioeconomic status, education level, and occupation, were collected. All patients underwent similar physical therapy protocols in the postoperative period, and no complications were observed in any patient. Postoperative satisfaction was assessed using the Patient-Rated Wrist Evaluation (PRWE) and the Disabilities of the Arm, Shoulder, and Hand (DASH) scores at 6 and 12 months post-surgery. Statistical analysis was conducted to evaluate the influence of ulnar fixation and sociodemographic factors on patient satisfaction. Result. Patients who underwent ulnar fixation (n=60) reported significantly higher satisfaction levels compared to those who did not (n=60), as evidenced by lower PRWE and DASH scores (p < 0.05). Age, gender, and socioeconomic status were significant predictors of postoperative satisfaction. Younger patients, females, and those with higher socioeconomic status exhibited greater improvements in functional outcomes and satisfaction. However, education level and occupation did not significantly influence satisfaction scores. Conclusion. Ulnar fixation in the surgical treatment of distal radius fractures accompanied by ulna styloid fractures is associated with improved postoperative satisfaction. Sociodemographic factors, particularly age, gender, and socioeconomic status, play a crucial role in patient-reported outcomes. Tailoring postoperative care to address these sociodemographic differences may enhance overall patient satisfaction and recovery

We have assessed the influence of isolated and combined rotational malunion of the radius and ulna on the rotation of the forearm. Osteotomies were made in both the radius and the ulna at the mid-diaphyseal level of five cadaver forearms and stabilised with intramedullary metal implants. Malunion about the axis of the respective forearm bone was produced at intervals of 10°. The ranges of pronation and supination were recorded by a potentiometer under computer control. We examined rotational malunions of 10° to 80° of either the radius or ulna alone and combined rotational malunions of 20° to 60° of both the radius and ulna. Malunion of the ulna in supination had little effect on rotation of the forearm. Malunion of either the radius or of the ulna in pronation gave a moderate reduction of rotation of the forearm. By contrast, malunion of the radius in supination markedly reduced rotation of the forearm, especially with malunion greater than 60°. Combined rotational malunion produced contrasting results. A combination of rotational malunion of the radius and ulna in the same direction had an effect similar to that of an isolated malunion of the radius. A combination in the opposite direction gave the largest limitation of the range of movement. Clinically, rotational malunion may be isolated or part of a complex angular/rotational deformity and rotational malunion may lead to marked impairment of rotation of the forearm. A reproducible method for assessing rotational malunion is therefore needed

We undertook a study on eight arms from fresh cadavers to define the clinical usefulness of the lesser sigmoid notch as a landmark when reconstructing the length of the neck of the radius in replacement of the head with a prosthesis. The head was resected and its height measured, along with several control measurements. This was compared with in situ measurements from the stump of the neck to the proximal edge of the lesser sigmoid notch of the ulna. All the measurements were performed three times by three observers acting independently. The results were highly reproducible with intra- and interclass correlations of > 0.99. The mean difference between the measurement on the excised head and the distance from the stump of the neck and the lesser sigmoid notch was −0.02 mm (−1.24 to +0.97). This difference was not statistically significant (p = 0.78). The proximal edge of the lesser sigmoid notch provides a reliable landmark for positioning a replacement of the radial head and may have clinical application

Introduction. The main postoperative complications in fixation of ulna shaft fractures are non-union and implant irritation using currently recommended 3.5-mm locking compression plates. An alternative approach using a combination of two smaller plates in orthogonal configuration has been proposed. The aim of this study was to compare the biomechanical properties of a single 3.5-mm locking compression plate versus double plating using one 2.5-mm and one 2.0-mm mandible plate in a human ulna shaft fracture model. Method. Eight pairs human ulnar specimens with a standardized 10-mm fracture gap were pairwise assigned for instrumentation with either a single 3.5-mm plate placed posteriorly, or for double plating using a 2.5-mm and a 2.0-mm mandible plate placed posteriorly under the flexor muscles and laterally under the extensor muscles. All constructs were initially non-destructively biomechanically tested in axial compression, torsion, and bending, which was followed by cyclic torsional loading to failure. Interfragmentary movements were monitored by means of optical motion tracking. Result. There were no significant differences between the two plating techniques for axial stiffness (p=0.335), torsional stiffness in supination (p=0.462), torsional stiffness in pronation (p=0.307), medio-lateral bending stiffness (p=0.522), and antero-posterior bending stiffness (p=0.143). During cyclic torsional loading over the first 3000 cycles, there were no significant differences between the two plating techniques for shear displacement across the fracture gap, p=0.324. The numbers of cycles until clinically relevant failure of 5° angular deformation were 1366±685 for double plating and 2024±958 for single plating, which was statistically non-significantly different, p>0.05. The constructs treated with both plating techniques failed due to bone breakage at the most distal screw. Conclusion. From a biomechanical perspective double plating of ulna shaft fractures using a 2.5-mm and a 2.0-mm locking mandible plate demonstrated equivalent fixation strength as conventional plating using a single 3.5-mm locking compression plate

This study was conducted to investigate the characteristics, complications, radiologic features and clinical course of patients undergoing reduction of forearm fractures in order to better inform patient prognosis and postoperative management. We conducted a retrospective cohort study of 1079 pediatric patients treated for forearm fractures between January 2014 and September 2021 in a 327 bed regional medical center. A preoperative radiological assessment and chart review was performed. Percent fracture displacement, location, orientation, comonution, fracture line visibility and angle of angulation were determined by AP and lateral radiographs. Percent fracture displacement was derived by: (Displacement of Bone Shafts / Diameter) x 100% = %Fracture Displacement. Angle of angulation and percent fracture displacement were calculated by averaging AP and lateral radiograph measurements. 80 cases, averaging 13.5±8.3 years, were identified as having a complete fracture of the radius and/or ulna with 69 receiving closed reduction and 11 receiving fixation via an intramedullary device or percutaneous pinning. Eight patients (10%) experienced complications with four resulting in a refracture and four resulting in significant loss of reduction (LOR) without refracture. Fractures in the proximal ⅔s of the radius were associated with a significant increase in complications compared to fractures in the distal ⅓ of the radius (31.6% vs 3.4%) (P=.000428). Likewise, a higher percent fracture displacement was associated with a decreased risk of complications (28.7% vs 5.9% displacement)(P=0.0403). No elevated risk of complications was found based on fracture orientation, angulation, fracture line visibility, forearm bone(s) fractured, sex, age or arm affected. Our result highlights radius fracture location and percent fracture displacement as markers with prognostic value following forearm fracture. These measurements are simply calculated via pre-reduction radiographs, providing an efficient method of informing risk of complications following forearm fracture

The purpose of this study is to enhance massive bone allografts osseointegration used to reconstruct large bone defects. These allografts show >50% complication rate requiring surgical revision in 20% cases. A new protocol for total bone decellularisation exploiting the vasculature can offer a reduction of postoperative complication by annihilating immune response and improving cellular colonization/ osseointegration. The nutrient artery of 18 porcine bones - humerus/femur/radius/ulna - was cannulated. The decellularization process involved immersion and sequential perfusion with specific solvents over a course of one week. Perfusion was realized by a peristaltic pump (mean flow rate: 6ml/min). The benefit of arterial perfusion was compared to a control group kept in immersion baths without perfusion. Bone samples were processed for histology (HE, Masson's trichrome and DAPI for cell detection), immunohistochemistry (IHC : Collagen IV/elastin for intraosseous vascular system evaluation, Swine Leukocyte Antigen – SLA for immunogenicity in addition to cellular clearance) and DNA quantification. Sterility and solvent residues in the graft were also evaluated with thioglycolate test and pH test respectively. Compared to native bones, no cells could be detected and residual DNA was <50ng/mg dry weight. Intramedullary spaces were completely cleaned. IHC showed the preservation of intracortical vasculature with channels bounded by Collagen IV and elastin within Haversian systems. IHC also showed a significant decrease in SLA signaling. All grafts were sterile at the last decellularization step and showed no solvent residue. The control group kept in immersion baths, paired with 6 perfused radii/ulnae, showed that the perfusion is mandatory to ensure complete decellularisation. Our results prove the effectiveness of a new concept of total bone decellularisation by perfusion. These promising results could lead to a new technique of Vascularized Composite Allograft transposable to pre-clinical and clinical models

There is currently no commercially available and clinically successful treatment for scapholunate interosseous ligament rupture, the latter leading to the development of hand-wrist osteoarthritis. We have created a novel biodegradable implant which fixed the dissociated scaphoid and lunate bones and encourages regeneration of the ruptured native ligament. To determine if scaphoid and lunate kinematics in cadaveric specimens were maintained during robotic manipulation, when comparing the native wrist with intact ligament and when the implant was installed. Ten cadaveric experiments were performed with identical conditions, except for implant geometry that was personalised to the anatomy of each cadaveric specimen. Each cadaveric arm was mounted upright in a six degrees of freedom robot using k-wires drilled through the radius, ulna, and metacarpals. Infrared markers were attached to scaphoid, lunate, radius, and 3rd metacarpal. Cadaveric specimens were robotically manipulated through flexion-extension and ulnar-radial deviation by ±40° and ±30°, respectively. The cadaveric scaphoid and lunate kinematics were examined with 1) intact native ligament, 2) severed ligament, 3) and installed implant. Digital wrist models were generated from computed tomography scans and included implant geometry, orientation, and location. Motion data were filtered and aligned relative to neutral wrist in the digital models of each specimen using anatomical landmarks. Implant insertion points in the scaphoid and lunate over time were then calculated using digital models, marker data, and inverse kinematics. Root mean squared distance was compared between severed and implant configurations, relative to intact. Preliminary data from five cadaveric specimens indicate that the implant reduced distance between scaphoid and lunate compared to severed configuration for all but three trials. Preliminary results indicate our novel implant reduced scapho-lunate gap caused by ligament transection. Future analysis will reveal if the implant can achieve wrist kinematics similar to the native intact wrist

The COVID-19 pandemic necessitated a pivot to online learning for many traditional, hands-on subjects such as anatomy. This, coupled with the increase in online education programmes, and the reduction of time students spend in anatomy dissection rooms, has highlighted a real need for innovative and accessible learning tools. This study describes the development of a novel 3-dimensional (3D), interactive anatomy teaching tool using structured light scanning (SLS) technology. This technique allows the 3D shape and texture of an object to be captured and displayed online, where it can be viewed and manipulated in real-time. Human bones of the upper limb, vertebrae and whole skulls were digitised using SLS using Einscan Pro2X/H scanners. The resulting meshes were then post-processed to add the captured textures and to remove any extraneous information. The final models were uploaded into Sketchfab where they were orientated, lit and annotated. To gather opinion on these models as effective teaching tools, surveys were completed by anatomy students (n=35) and anatomy educators (n=8). Data was collected using a Likert scale response, as well as free text answers to gather qualitative information. 3D scans of the scapula, humerus, radius, ulna, vertebrae and skull were successfully produced by SLS. Interactive models were produced via scan data in Sketchfab and successfully annotated to provide labelled 3D models for examination. 94% of survey respondents agreed that the interactive models were easy to use (n=35, 31% agree and 63% strongly agree) and 97% agreed that the 3D interactive models were more useful than 2D images for learning bony anatomy (n=35; 26% agree and 71% strongly agree). This initial study has demonstrated a suitable proof-of-concept for SLS technology as a useful technique for producing 3D interactive online tools for learning and teaching bony anatomy. Current studies are focussed on determining the SLS accuracy and the ability of SLS to capture soft tissue/joints. We believe that this tool will be a useful technique for generating online 3D interactive models to study orthopaedic anatomy

We have investigated the anatomy of the proximal part of the ulna to assess its influence on the use of plates in the management of fractures at this site. We examined 54 specimens from cadavers. The mean varus angulation in the proximal third was 17.5° (11° to 23°) and the mean anterior deviation 4.5° (1° to 14°). These variations must be considered when applying plates to the dorsal surface of the ulna for Monteggia-type fractures. A pre-operative radiograph of the contralateral elbow may also be of value

Coronoid fractures account for 2 to 15% of the cases with elbow dislocations and usually occur as part of complex injuries. Comminuted fractures and non-unions necessitate coronoid fixation, reconstruction or replacement. The aim of this biomechanical study was to compare the axial stability achieved via an individualized 3D printed prosthesis with curved cemented intramedullary stem to both radial head grafted reconstruction and coronoid fixation with 2 screws. It was hypothesized that the prosthetic replacement will provide superior stability over the grafted reconstruction and screw fixation. Following CT scanning, 18 human cadaveric proximal ulnas were osteotomized at 40% of the coronoid height and randomized to 3 groups (n = 6). The specimens in Group 1 were treated with an individually designed 3D printed stainless steel coronoid prosthesis with curved cemented intramedullary stem, individually designed based on the contralateral coronoid scan. The ulnas in Group 2 were reconstructed with an ipsilateral radial head autograft fixed with two anteroposterior screws, whereas the osteotomized coronoids in Group 3 were fixed in situ with two anteroposterior screws. All specimens were biomechanically tested under ramped quasi-static axial loading to failure at a rate of 10 mm/min. Construct stiffness and failure load were calculated. Statistical analysis was performed at a level of significance set at 0.05. Prosthetic treatment (Group 1) resulted in significantly higher stiffness and failure load compared to both radial head autograft reconstruction (Group 2) and coronoid screw fixation, p ≤ 0.002. Stiffness and failure load did not reveal any significant differences between Group 2 and Group 3, p ≥ 0.846. In cases of coronoid deficiency, replacement of the coronoid process with an anatomically shaped individually designed 3D printed prosthesis with a curved cemented intramedullary stem seems to be an effective method to restore the buttress function of the coronoid under axial loading. This method provides superior stability over both radial head graft reconstruction and coronoid screw fixation, while achieving anatomical articular congruity. Therefore, better load distribution with less stress at the bone-implant interface can be anticipated. In the clinical practice, implementation of this prosthesis type could allow for early patient mobilization with better short- and long-term treatment outcomes and may be beneficial for patients with irreparable comminuted coronoid fractures, severe arthritic changes or non-unions

Summary Statement. This 3-dimensional CT study on cadaveric proximal ulna provides further insight into the size and geometry of the proximal ulna intramedullary cavity with potential applications to design and sizing of proximal ulna components. Introduction. Total elbow arthroplasty (TEA) is an established treatment for varying pathologies of the elbow with very good functional outcomes. Optimal fit of ulna components in TEA is predicated on a detailed appreciation of the 3-dimensional anatomy of the proximal ulna intra-medullary cavity, but literature remains scarce. Three-dimensional (3D) models of the proximal ulna have been constructed using computed tomography (CT) programs, accurately defining the angular relations with the cross-sectional extra-medullary dimensions. However, current CT-based thresholding techniques lack accuracy in differentiating cortical from cancellous bone in the metaphyseal region, and thus cannot properly define the intra-medullary region of uncored proximal ulnae. We investigate the geometric dimensions of the proximal ulna intra-medullary cavity using CT studies of cored cadaveric ulnae. Patients & Methods. Three-dimensional models based on CT data of 17 manually cored cadaveric proximal ulnae were created using Matlab program and analyzed. The cadaveric specimens were dissected to identify the medullary canal and coring of the canal of the proximal ulna to exclude the cancellous bone was performed as for ulna canal preparation during TEA. Using the center of a circle fitted over the trochlear ridge as the origin, the diameter, coronal and sagittal angulation of the canal were determined. The diameter, posterior and lateral offsets of the proximal medullary canal were plotted against the normalised axial distance from the origin which was represented in terms of R, the radius of the circle fitted to the trochlear ridge. The normalization of the axial distance was done to compensate for the varying individual ulna lengths. Results. The mean of the radius of the circle which was fitted to the trochlear ridge, R, was found to be 16.64 ± 2.71 mm. The minimum diameter of the canal increased from the origin and peak at 2.3R (just distal to the coronoid process) with a value of 7.08 ± 1.74 mm, decreasing in a linear fashion to 4.48 ± 0.91 mm at 6R. There was an increasing posterior offset which was linear in nature (R. 2. = 0.954) up to 6R (approximately 97mm from the origin). Likewise, the lateral offset increased in a linear fashion (R. 2. = 0.996). Discussion. The findings of our study most likely represent the effective minimum diameter for optimal implant placement, which are consistent with previously documented cadaveric dimensions. The findings also support the current tapered component design of the proximal ulna stemmed implants without the need for significant angulation. Conclusion. Our study provides further insight into the size and geometry of the proximal ulna intramedullary cavity with potential applications to design and sizing of proximal ulna components

Background and Objectives. Triangular fibrocartilaginous complex (TFCC) tears are common sources of ulna sided wrist pain and resultant functional disability. Diagnosis is based on history, clinical examination and radiological evidence of a TFCC central perforation or radial/ulna tear. The purpose of this study is therefore to evaluate the diagnostic accuracy of Magnetic Resonance Imaging (MRI) and Magnetic Resonance Arthrography (MRA) in the detection of TFCC injury in the adult population. Methods. Published and unpublished literature databases were systematically review independently by two researchers. Two-by-two tables were constructed to calculate the sensitivity and specificity of MRI or MRA investigations against arthroscopic outcomes. Pooled sensitivity and specificity values and summary Receiver Operating Characteristic curve (sROC) evaluations were performed. Methodological quality of each study was assessed using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies) tool. Results. Twenty one studies were eligible, including 910 wrists. On meta-analysis, MRA was superior to MRI in the investigation of complete TFCC tears with a pooled sensitivity of 0.75 (95% Confidence Interval (CI): 0.70, 0.79) and specificity of 0.81 (95% CI: 0.76, 0.86), compared to MRAs 0.84 (95% CI: 0.79, 0.89), and 0.95 (95% CI: 0.92, 0.98) respectively. MRA and MRI performed at greater field strengths reported greater sensitivity and specificity findings. For 3.0 Tesla (T) MRI, the meta-analysis indicated a sensitivity of 0.86 (95% CI: 0.65, 0.97), and specificity of 1.00 (0.87, 1.00). In comparison, the pooled sensitivity for the 1.5T MRI assessment was 0.70 (95% CI: 0.64, 0.75) and specificity of 0.79 (95% CI: 0.72, 0.85). This trend was repeated for MRA where 3.0T MRA exhibited a sensitivity was 1.00 (95% CI: 0.79, 1.00) and specificity of 1.00 (95% CI: 0.82, 1.00), whilst pooled analysis 1.5T MRA demonstrated a sensitivity of 0.83 (95% CI: 0.78, 0.89) and specificity of 0.95 (95% CI: 0.91, 0.98). There was insufficient data to assess the diagnostic test accuracy of partial TFCC lesions. Conclusions. Given its acceptable diagnostic test accuracy, it is recommended that in cases where there are questions over the diagnosis and subsequent management of patients with ulna wrist pain, a MRA should be undertaken rather than MRI

Advancements in treating complications of operatively treated distal radius fractures. We will review tips and tricks to avoid complications associated with operative fixation of these complicated injuries. We will cover treatment of the distal radioulnar joint, associated distal ulna fracture, complications of malreduction and implant prominence. During this session, we will review the latest techniques for treating these complex distal radius fractures and how to avoid associated complications

We have evaluated the effect of the short-term administration of low therapeutic doses of modern COX-2 inhibitors on the healing of fractures. A total of 40 adult male New Zealand rabbits were divided into five groups. A mid-diaphyseal osteotomy of the right ulna was performed and either normal saline, prednisolone, indometacin, meloxicam or rofecoxib was administered for five days. Radiological, biomechanical and histomorphometric evaluation was performed at six weeks. In the group in which the highly selective anti-COX-2 agent, rofecoxib, was used the incidence of radiologically-incomplete union was similar to that in the control group. All the biomechanical parameters were statistically significantly lower in both the prednisolone and indometacin (p = 0.01) and in the meloxicam (p = 0.04) groups compared with the control group. Only the fracture load values were found to be statistically significantly lower (p = 0.05) in the rofecoxib group. Histomorphometric parameters were adversely affected in all groups with the specimens of the rofecoxib group showing the least negative effect. Our findings indicated that the short-term administration of low therapeutic doses of a highly selective COX-2 inhibitor had a minor negative effect on bone healing

Bone loss continues to be a clinical and therapeutic problem. Bone reconstruction of osseous defects is a challenge after fracture and traumatic injuries, infections and tumors. The common objective is to regenerate bone morphology and function. Several techniques have been developed to promote bone formation, but the advent of new biomaterials allows us to take an entirely different approach to the treatment of bone voids. However, the use of bone substitutes should be considered carefully, as not all biomaterials behave the same way in humans. Calcium phosphate ceramics are osteoconductive materials that promote bone regeneration. The aim of this study was to retrospectively evaluate the clinical, radiographic and histological results of bone loss treated with an adjunct injectable biphasic bone substitute (BBS). We analysed the results of patients with fractures and a bone defect that were treated using an injectable BBS (calcium sulfate + hydroxyapatite) and those that were treated using the same bone substitute with antibiotic (gentamicin and/or vancomycin). Patient outcome was evaluated clinically and radiographically. In 9 cases samples for histological analysis were obtained. From July 2009 to May 2015, 126 cases (cs) on 111 patients (pt) (calcaneus: 53 cs, 47 pt; tibia: 32 cs, 30 pt; Femur: 14 cs, 9 pt, Elbow: 5 cs, 5 pz; humerus 2 cs, 2 pz; wrist 7cs, 7pz; forearm 6 cs, 4 pz; foot 2 cs, 2 pz; Phalanx 5 cs, 5 pt) were treated at our hospital with a BBS. The mean follow-up was 15 months, and bone ingrowth was assessed at 1, 2, 3, 6 and 12 months by X-ray. In all cases, the calcium sulphate phase of the BBS dissolved within 4–6 weeks, and new bone formation was observed at 6 months. On six patients large bone was treated with a revision surgery (autologous cancellous bone graft combined with BBS and antibiotic). No complications were reported. The 9 histological samples confirmed gradual remodeling and regeneration of the bone substitute over time. This biomaterial is versatile, offers a good augment for hardware and bone alignment, is biocompatible and osteoconductive, and has allowed us to manage significant bone voids. Histological analysis of samples from the tibia, ulna and calcaneus have confirmed the ability of this bone substitute to remodel into bone

Introduction. Two randomised trials concluded cast type (above or below elbow) makes no significant difference in the re-displacement rate of paediatric forearm fractures involving the distal third of the radius. This has not, however, led to the universal use of below elbow casts. In particular we noted one trial reported significant re-displacement in 40% or more of cases, which was much higher than we would expect. To review the radiological outcomes and need for re-manipulation of paediatric distal forearm fractures treated with closed manipulation under anaesthesia in our institution, in part for subsequent comparison with published results. All forearm fractures treated at a specialist children's hospital in one year were reviewed retrospectively. Based on the methodology of one trial, we included all fractures involving the distal third of the radius, with or without an ulna fracture, which underwent closed manipulation. Outcomes were radiological alignment using existing radiographs and need for re-manipulation. Cast type was at the discretion of the treating surgeon. The radiological criteria for re-displacement were based on published methodology. 79 children underwent manipulation, 71 receiving above elbow casts and 8 below elbow casts. Radiologically 21% of injuries treated in an above elbow cast re-displaced (15/71) compared to 38% of those in below elbow plasters (3/8). In 2 cases the re-displacement was treated with re-manipulation. The preference in our institution was clearly for above elbow casts in this injury pattern. The small number of below elbow casts in our series limits any comparisons. Our rate of re-displacement using above elbow casts was half that of one of the published studies, so the existing literature is not consistent with our experience

Summary. Consistent load distributions with over-sizing of radial head implants show minimal variance in interosseus ligament (IOL) and triangular-fibrocartilage complex (TFCC) tension, both of which are essential in distribution of load at the elbow. Introduction:Changes in loading distribution at the elbow have not been studied with radial head (RH) arthroplasty. Difficulty arises concerning distribution variability between loading methods and magnitudes, and with implant oversizing. Method. RC joint capsule were exposed using the Kocher approach in seven fresh-frozen cadaver Humeri. Specimens were loaded axially in an MTS machine with humeri at 90° and wrist neutral. The arms were cycled in load control between 13N–130N until steady-state was reached for each trial. After loading in neutral, the arms were rotated to 60° supination (60S) and 60° pronation (60P), the test repeated. The radial head was excised and Co-Cr implant inserted. Sizings 0mm, +2mm, +4mm were simulated using 2mm plastic spacers on the stem. A Tekscan pressure map transducer at RC recorded loading. The recorded Tekscan loads were organised according to sizing (native, 0mm, +2mm, +4mm) for each specimen. The max/min load values were recorded and the difference, ΔL was calculated. The Max and ΔL values from each sizing were percentage paired with the respective native value. The ΔL values were used to discern load distribution. A linear regression was done using the RC loading plotted against the applied load to visualise the change of load distribution with changing applied loads. Data was analyzed using one-way analysis of variance. Result. Max load values and percent pairings are shown (one-way Anova). There was a direct relationship between loading at the RC joint and sizing of the radial head implant. The loading increases with over-sizing of the RH implant. Implant RC loading differences (ΔL) were compared percent paired with native values, and as total values. One-way ANOVA comparisons can be seen showing a trend. A linear regression was done (RC v. Applied load) showing a linear relation between loading at the RC joint and sizing of the radial head implant for all forearm positions. Conclusion. Linear relation between RC and applied load shows consistent distribution at any load. Equivalence of ΔL values indicate consistent distribution with implant oversizing. Consistent load distributions with over-sizing show minimal variance in interosseus ligament (IOL) and triangular-fibrocartilage complex (TFCC) tension, both of which are essential in distribution of load at the elbow. The TFCC and IOL loading are both reliant on radius position in relation to the ulna. It can be inferred that with minimal change in IOL and TFCC loading, there is little radial translation resulting from additional RH length

We have evaluated in vivo a novel, polymer-based, matrix for tissue engineering of bone. A segmental defect of 15 mm was created in the ulna of New Zealand white rabbits to determine the regenerative properties of a porous polylactide-co-glycolide matrix alone and in combination with autogenous marrow and/or the osteoinductive protein, BMP-7. In this study four implant groups were used: 1) matrix alone; 2) matrix with autogenous marrow; 3) matrix with 20 μg of BMP-7; and 4) matrix with 20 μg of BMP-7 and autogenous marrow. The results showed that the degree of bone formation was dependent on the properties of the graft material. The osteoconductive sintered matrix structure showed significant formation of bone at the implant-bone interface. The addition of autogenous marrow increased the penetration of new bone further into the central area of the matrix and also increased the degree of revascularisation. The osteoinductive growth factor BMP-7 induced penetration of new bone throughout the entire structure of the implant. The most effective treatment was with the combination of marrow cells and osteoinductive BMP-7

Summary. Increased lateral ulnotrochlear joint space due to improper sizing in radial head arthroplasty may result in medial collateral ligament laxity, leading to increased osteophytes and arthritis. Introduction. Radial head (RH) arthroplasty is a common response to comminuted RH fractures. Typical complications include improper sizing, leading to changes in joint kinematics. Evidence of these changes should be visible through fluoroscopic images of affected joints. The two examined changes in this study are the ulnar deviation from distal radial translation (DRT), and the widening of the lateral ulnotrochlear joint space (LUT). Methods. Eight fresh-frozen cadaver arms were used. Initial images were taken with the native RH intact. The Kocher approach exposed the radiocapitellar (RC) joint capsule, preserving all ligaments. The RH was excised and Integra Katalyst CoCr (Plainsboro, NJ) telescoping, bipolar, RH inserted. Images were taken with implant sizings: −2mm, 0mm, +2mm, and +4mm, (from native) using 1mm washers preventing implant bipolarity. AP fluoroscopic images of the elbow were taken at full extension. Joint spaces were measured using image analysis, normalised using known radio-opaque lengths. Four LUT measurements were made, two medially and two laterally, and normalised by measuring the RH implant diameter. Each set (medial and lateral) were averaged together and the resulting value used for all comparisons. Images of distal ulnar deviation at the wrist were taken with the wrist in supination, the hand rotated medially. Measurements were from the distal medial radial tip to the distal lateral ulnar tip. Images were normalised by placing a scalpel in the same plane as measurement. Results. DRT values were difference paired for each arm using the 0mm values as baselines. One-way ANOVA of the paired values resulted in significant DT with sizing increases (p<0.01). The quotient of DRT and sizing determined comparative impact with the LUT increase. LUT joint gap measurements were percentage paired, with natives as the baseline, and One-way ANOVA used. A significant increase in LUT spacing occurred with increased sizings (p<0.01). Discussion. Increased ulnar deviation can increase loading on the TFCC, leading to possible TFCC tear, increased articular cartilage wear from carpal misalignment, and eventual wrist instability and arthritis. The percentage of the radial lengthening is represented in DRT. Over-sizing results in small percentages of increased radial length at the wrist, therefore deviation at the elbow must take place, either through rotation of the ulna, or translation. Either of these can be seen through LUT measurements. Previous measurements of the LUT space were made by Frank (2009), with similar results. This was being used as a method of improper sizing detection using radiographs. The percentage difference of LUT space for corresponding sizing: there is an increase in LUT space for every sizing; maybe due to loosening of the soft tissue from arthroplasty. Increased LUT space indicates the medial translation of proximal ulna. This can result in Medial Collateral Ligament laxity, leading to increased osteophytes, and arthritis. Use and non-treatment, can create a chronic, painful, disorder

Limited success in regenerating large bone defects has been achieved by bridging them with osteoconductive materials. These substitutes lack the osteogenic and osteoinductive properties of bone autograft. A direct approach would be to stimulate osteogenesis in these biomaterials by the addition of fresh bone-marrow cells (BMC). We therefore created osteoperiosteal gaps 2 cm wide in the ulna of adult rabbits and either bridged them with coral alone (CC), coral supplemented with BMC, or left them empty. Coral was chosen as a scaffold because of its good biocompatibility and resorbability. In osteoperiosteal gaps bridged with coral only, the coral was invaded chiefly by fibrous tissue. It was insufficient to produce union after two months. In defects filled with coral and BMC an increase in osteogenesis was observed and the bone surface area was significantly higher compared with defects filled with coral alone. Bony union occurred in six out of six defects filled with coral and BMC after two months. An increase in the resorption of coral was also observed, suggesting that resorbing cells or their progenitors were present in bone marrow and survived the grafting procedure. Our findings have shown that supplementation of coral with BMC increased both the resorption of material and osteogenesis in defects of a clinical significance