Introduction. A prospective study was done using Kirschner (K) wires to internally fix capitellum fractures and its results were analysed. Materials/Methods. Since 1989, unstable displaced 17 capitellum fractures were anatomically reduced and internally fixed by inserting K wires in coronal plane from the capitellum into trochlea. The lateral end of wires were bent in form of a staple behind the fracture plane and anchored into the lateral humeral condyle with pre-drilled holes. Additional screws were used in 2 cases to stabilise the lateral pillar comminution. The capitellum was exposed with a limited modified lateral elbow approach between anconeus and extensor carpi ulnaris. The capsule was reflected anteriorly to expose the capitellum and trochlea. The deeper dissection was limited anterior to lateral collateral ligament (LCL) keeping it intact. The capitellum fragment was reposition under the radial head and anatomically reduced by full flexion of elbow and then internally fixed. Total 17 patients (7 males and 10 females) with average ages 34.8 years(14 to 75) had fractures, Type I: (Hans Steinthal #) 12, Type II: (Kocher Lorez #) 1, and Type III: (Broberg and Morrey #) 4. Post-operatively the patients were not given any immobilisation and were mobilised immediately. Results. Patients were assessed clinically and radiologically. Average followup was 31.7 (18–35) months. Capitellum fractures healed in all the patients. Mayo elbow score was excellent in 12, good in 4, and fair in 1 patient. Average elbow ROM was 5 to 132 degrees, pronation 84.5 (79–90) degrees and supination 88 (85–91) degrees. Complications seen were wire pain in 4 patients, loosening of wires in 2 which required early removal. We did not see any infection, non-union or avascular necrosis in the time scale we studied. Conclusions. We found a simple manoeuvre of hyper-flexion of elbow reduced the capitellum anatomically, and K wires stapling technique to be very easy and stable. A limited exposure of capitellum helped to restore immediate stable elbow with good function

Objectives. Surgical treatment is standard for advanced osteochondritis dissecans (OCD) of the humeral capitellum. When cartilage is seen to be separated or completely detached, this fragment fixation is not usually applied. There have been reports of cases in which advanced OCD of the humeral capitellum progressed to osteoarthritis (Fig), particularly in cases which involved the lateral wall. In these cases, every attempt should be made to reconstruct the lateral wall to avoid osteoarthritis. In this study, we followed up cases with rib osteochondral autograft transplantation technique. Methods. Subjects were 20 cases who were followed up until after they started pitching. The mean age was 13.8 years old and the mean observation period was 2 years and 6 months (from 7 months to 6 year 3 months). Kocher's approach was used to give a good access to the aspect of the radiohumeral joint. The majority of cases suffered from extensive OCD of the elbow. Detached fragment was removed (Fig. 2a) and graft from 5. th. or 6. th. rib with screw fixation was performed on 12 patients and 8 received fixation with no material (Fig. 2b). Follow-up assessment included the range of motion, start time of playing catch and throwing a ball with full power, sports activity, evaluation of radiography, a subjective (including Pain, Swelling, Locking/Catching and Sport activity) and objective (Flexion contracture, Pronation/Supination and sagittal arc of motion) modified elbow rating system by Timmeman et al. We also investigated the details of the arthroscopy observations and the 2nd arthroscopy findings for 4 cases. Results. Preoperative elbow extension increased from −13.5 to −10 degrees and elbow flexion increased from 117 to 123 degrees, but no significant differences were found. All but one patient resumed baseball sporting activity. Catching was started at an average of 3.5 (2 to 5.5 months) months postoperatively and pitching the ball with full power was achieved at 6.7 months. One case was found to have degenerative changes on plain X-ray, and two cases were found to have deviated screws. The mean elbow rating system subjective score improved significantly from 63.9.5 to 89.5 points, as did the overall rating, increasing from 131.6 to 164.8 points. The 2. nd. arthroscopy observations for 4 patients showed that 2 experienced pain due to the loose body, 1 had a limitation in range of motion due to spur formation, and 1 had a screw deviation. Graft survival was observed in two out of four cases. Partial detachment was observed in two cases. Conclusion. Recovery of articular facets with hyaline cartilage were possible using this surgical technique, and in addition, the costal-costochondral grafts, comprising cortical and cancellous bone, were simultaneously transplanted en bloc. This indicates that it is adequate treatment for extensive OCD. All the patients started pitching 3 months postoperatively and returned to full baseball activities after 6 months. Even in cases with extensive OCD, with large osseous and cartilaginous deficits, the surgical technique was useful and showed favorable results

Hemiarthroplasty is a common procedure that is an attractive alternative to total arthroplasty because it conserves natural tissue, allows for quicker recovery, and has a lower cost. One significant issue with hemiarthroplasties is that they lead to accelerated wear of the opposing native cartilage, likely due to the high stiffness of the implant. The purpose of this study was to investigate the range of currently available biomaterials for hemiarthroplasty applications. We employed a finite-element (FE) model of a radial head implant against the native capitellum as our joint model. The FE model was developed in ABAQUS v6.14 (Dassault Systèmes Simulia Corp., Providence, RI, USA). A solid axisymmetric concave implant with seven different materials and the native radial head were evaluated, six modelled as elastic materials with different Young's moduli (E) and Poisson's Ratios (ν), and one modelled as a Mooney-Rivlin hyperelastic material. The materials investigated were CoCr (E=230 GPa, ν = 0.3), PEEK (E=3.7 GPa, ν = 0.36), HDPE (E=2.7 GPa, ν = 0.42), UHMWPE (E=0.69 GPa, ν = 0.49), Bionate 75D (E=0.288 GPa, ν = 0.39), Bionate 55D (E=0.039 GPa, ν = 0.45), and Bionate 80A (modelled as a Mooney-Rivlin hyperelastic material). A load of 100 N was applied to the radius through the center of rotation representing a typical load through the radius. The variable of interest was articular contact stress on the capitellum. The CoCr implant had a maximum contact stress over 114% higher than the native radial head. By changing the material to lower the stiffness of the implant, the maximum contact stress was 24%, 70%, 105%, 111%, 113%, and 113% higher than the native radial head for Bionate 80A, Bionate 55D, Bionate 75D, UHMWPE, HDPE, and PEEK respectively. This work shows that lowering implant stiffness can reduce the contact stress on cartilage in hemiarthroplasty implants. By changing the material below a Young's modulus of ∼100 MPa elevated stresses on the capitellum can be markedly reduced and hence potentially reduce or prevent degenerative changes of the native articulating cartilage. Low stiffness implant materials are not a novel concept, but to date there have been few that investigate materials (such as Bionate) as a potential load bearing material for implant applications. Further work is required to assess the efficacy of these materials for articular bearing applications

Purpose. Capitellum hemiarthroplasty is an emerging concept. The current metallic capitellar implants have spherical surface shapes, but the native capitellum is not spherical. This study evaluated the effect of capitellar implant shape on the contact mechanics of the radiocapitellar joint when articulating with the native radial head. Method. Eight paired radii and humeri were potted in a custom jig. Articular casts were made with medium-viscosity resin while 85 N of axial load was applied to the reduced radiocapitellar joint at 0, 45, and 90 of elbow flexion, and at neutral, 50 pronation and 50 supination at each flexion angle. The native radiocapitellar articulation was compared to capitellar hemiarthroplasties of two surface designs (anatomical and spherical). Contact area and shape (circularity) were determined. Circularity was defined as the ratio of the minor axis and major axis of the shape. Results. At 0 of flexion, the anatomical hemiarthroplasty had a contact area of 52–70% that of the native articulation (p=0.03), while the spherical hemiarthroplasty had a contact area 40–42% that of the native articulation (p=0.003). At 45 of flexion, both hemiarthroplasties displayed contact area <53% that of the native joint (p<0.007). At 90 of flexion, the hemiarthroplasties had contact areas ranging from 40–70% that of the native articulation (p=0.1). The two capitellar implants had similar contact areas at all flexion angles tested (p>0.05). The contact shape of the native radiocapitellar articulation was ellipsoid, with a range of circularity values from 0.530.19 to 0.720.16, depending on the flexion and rotation angle. At 0 and 90 flexion, there was no difference in contact shape between the native articulation, the anatomical, or spherical implant (p>0.05). At 45 flexion, the anatomical implant contact was less circular than either the native articulation (p=0.006) or the spherical hemiarthroplasty (p=0.002). Conclusion. Metallic capitellar hemiarthroplasty causes a significant reduction in contact area at 0 and 45 elbow flexion, which may have important long-term implications for wear of the radial head cartilage. This reduction is similar to previous reports, which have evaluated the effect of metallic radial head hemiarthroplasty articulating with the native capitellum. More compliant alternative materials are needed to improve the contact characteristics of metallic capitellar hemiarthroplasties. Although the anatomical hemiarthroplasty was created from a detailed morphological study of the capitellum, the anatomical implant failed to completely reproduce the contact native shape. The theoretical advantages of a more anatomical capitellar implant shape may not be realized clinically, suggesting a spherical implant, which is easier to manufacture and implant, may be adequate for patient application. Further studies are required to delineate the effect of this altered contact morphology on implant function and radial head wear in-vivo

Background. Fractures of the radial head result from an axial force that causes impaction against the capitellum. Associated lesions of the capitellum in this pattern of injury have been previously reported in the orthopaedic literature as an uncommon occurrence. Methods. All patients presenting to the clinics of the senior surgeon between 1998-2008 with radial head fractures requiring surgery were included. Data collected included demographics (age, gender, side of injury), mechanism, timing of injury and injury type (Mason classification). Intraoperative findings including evidence of union, capitellar injury, associated joint dislocation, collateral ligament injury, and any other fractures around the elbow were documented. Results. We reviewed 109 consecutive patients presenting with radial head fractures. 67% of the patients were found to have the PLUCCAR lesion, a capitellar slither of cartilage impacted in the radial fracture. Of these, 76.9% of patients with a Mason I injury had a PLUCCAR lesion, 76.7% of patients with Mason II injury had a PLUCCAR lesion, and only 33.3% of patients with Mason III lesion had a PLUCCAR lesion. 13 patients had a pre-existing non-union, 84% of whom had a PLUCCAR lesion. 19 patients were found to have a malunion, 84% of whom were found to have the PLUCCAR lesion. Conclusion. Injury to the capitellum is commonly associated with radial head fracture. We term impaction of a capitellar fragment in the radius a PLUCCAR lesion. There is an increased incidence of this injury in less comminuted radial head fractures, and in patients presenting with non union or malunion of a radial head fracture

Purpose. The measurement of radial head translation about the capitellum (in percent): the radio-capitellum ratio (RCR) has proven to have excellent inter- and intra-observer reliabilities when measuring the RCR on a lateral radiological view of elbows at 90° of flexion and in the neutral position of the forearm. However, in the clinical setting, radiographs may be taken with the elbow in different positions. However, the purpose was to validate the RCR measurement method on elbows in different positions in flexion-extension and in different positions of the forearm in pronation-supination. Method. Fifty-one healthy volunteers were recruited to evaluate the RCR in different elbow positions. Lateral elbow radiographs were taken with the elbow in different magnitude of ROM: maximal extension, maximal flexion, elbow at 90° and forearm in neutral, elbow at 90° and forearm in supination and elbow at 90° and forearm in pronation. The measurements of the RCR were done using the software SliceOmatic. ANOVA and paired T-test were used to assess the difference of the RCR depending on the position of the elbow and of the forearm. Pearson coefficients were calculated to obtain the correlation between the RCR in each different position. Results. The mean RCR for each position were the following: elbow in maximal extension: −2%±7%, elbow in maximal flexion: −5%±9%, elbow at 90° and forearm in neutral: −2%±5%, elbow at 90° and forearm in supination: 1%±6% and elbow at 90° and forearm in pronation: 1%±5%. According to the Anova results, a significant difference exists between the RCR in different elbow positions (p=0.01) and in the different forearm positions (p<0.001). Paired T-test confirmed a significant difference between maximal elbow flexion and elbow flexion at 90° (p=0.003), as well as for maximal elbow extension and maximal elbow flexion (p=0.034). According to the Pearson coefficient, significant correlations exist between: elbow flexion at 90° and in maximal flexion (r=0.19, p=0.050); the forearm in neutral and in supination (r=0.34, p<0.001); the forearm in neutral and in pronation (r=0.42, p<0.001). Conclusion. The RCR method is dependent on elbow (flexion-extension) and forearm (pronation-supination) positions. At both maximal elbow positions in flexion and extension, the measurements of the RCR have a higher standard deviation. In order to decrease its variability, we recommend as a convention measuring the RCR on lateral radiographs with the elbow at 90° and the forearm in neutral position. However, 95% of the values of RCR (except in maximal flexion which is unusual in trauma) are included in the normal range of RCR from −5% to 13%. Thus a value outside this range in any elbow positions (except maximal flexion) or any forearm positions must raise doubt on elbow alignment. Then, with a capitellum of 25 mm of diameter, the translation of the radial head must be less than 1 mm posterior and less than 3 mm anterior from the center of the capitellum

Total elbow arthroplasty (TEA) usage is increasing owing to expanded surgical indications, better implant designs, and improved long-term survival. Correct humeral implant positioning has been shown to diminish stem loading in vitro, and radiographic loosening in in the long-term. Replication of the native elbow centre of rotation is thought to restore normal muscle moment arms and has been suggested to improve elbow strength and function. While much of the focus has been on humeral component positioning, little is known about the effect of positioning of the ulnar stem on post-operative range of motion and clinical outcomes. The purpose of this study is to determine the effect of the sagittal alignment and positioning of the humeral and ulnar components on the functional outcomes after TEA. Between 2003 and 2016, 173 semi-constrained TEAs (Wright-Tornier Latitude/Latitude EV, Memphis, TN, USA) were performed at our institution, and our preliminary analysis includes 46 elbows in 41 patients (39 female, 7 male). Patients were excluded if they had severe elbow deformity precluding reliable measurement, experienced a major complication related to an ipsilateral upper limb procedure, or underwent revision TEA. For each elbow, saggital alignment was compared pre- and post-operatively. A best fit circle of the trochlea and capitellum was drawn, with its centre representing the rotation axis. Ninety degree tangent lines from the intramedullary axes of the ulna and humerus, and from the olecranon tip to the centre of rotation were drawn and measured relative to the rotation axis, representing the ulna posterior offset, humerus offset, and ulna proximal offset, respectively. In addition, we measured the ulna stem angle (angle subtended by the implant and the intramedullary axis of the ulna), as well as radial neck offset (the length of a 90o tangent line from the intramedullary axis of the radial neck and the centre of rotation) in patients with retained or replaced radial heads. Our primary outcome measure was the quickDASH score recorded at the latest follow-up for each patient. Our secondary outcome measures were postoperative flexion, extension, pronation and supination measured at the same timepoints. Each variable was tested for linear correlation with the primary and secondary outcome measures using the Pearson two-tailed test. At an average follow-up of 6.8 years (range 2–14 years), there was a strong positive correlation between anterior radial neck offset and the quickDASH (r=0.60, p=0.001). There was also a weak negative correlation between the posterior offset of the ulnar component and the qDASH (r=0.39, p=0.031), and a moderate positive correlation between the change in humeral offset and elbow supination (r=0.41, p=0.044). The ulna proximal offset and ulna stem angle were not correlated with either the primary, or secondary outcome measures. When performing primary TEA with radial head retention, or replacement, care should be taken to ensure that the ulnar component is correctly positioned such that intramedullary axis of the radial neck lines up with the centre of elbow rotation, as this strongly correlates with better function and less pain after surgery

Introduction. Isolated trochlea fractures are very rare and have only been described previously as case reports. Aims. To report on a case of isolated trochlea fracture and to present a review of the literature. Results. There have only been four previous reports of isolated trochlea fracture. Our fifth case is included in the analysis of the literature given below. Average age 26 (Range 12–33). 60% female, 80% left sided. Dominance only stated in 40% of cases- 50% dominant side. Mechanism of injury: 60% low velocity fall onto an outstretched hand, 40% high velocity- RTA & fall off horse- exact mechanism of injury unknown. Patients all presented with elbow held in flexion, pain and swelling over the medial aspect and a painfully reduced range of motion. Diagnosis made on plain radiographs in 80%, tomograms required in 20%. AP noted to be essential to differentiate from more common capitellum fracture. 20% of fractures associated with comminution. Management consisted of open reduction through a medial approach and internal fixation in 80% (20% headless screw, 20% k-wire, 40% 4.0mm partially threaded cancellous screws) and olecranon traction in 20%. Elbows were immobilised from 3 to 8 weeks. Time to union ranged from 6 weeks (80%) to 13 weeks (20%). Outcomes were uniformly excellent with 40% being asymptomatic with a FROM, 20% asymptomatic with 10 degrees loss of extension and 40% asymptomatic with 5–20 degrees loss of flexion. There were no reported complications. Conclusion. These are rare injuries and can occur through high and low energy mechanisms. They tend to occur in younger age groups. Diagnosis can be made readily with plain radiographs- the AP is essential in differentiating it from the more common capitellum fracture. The prognosis for this intra-articular fracture is good to excellent

Background. Humeral version is the twist angle of the humeral head relative to the distal humerus. Pre-operatively, it is most commonly measured referencing the transepicondylar axis, although various techniques are described in literature (Matsumura et al. 2014, Edelson 1999, Boileau et al., 2008). Accurate estimation of the version angle is important for humeral head osteotomy in preparation for shoulder arthroplasty, as deviations from native version can result in prosthesis malalignment. Most humeral head osteotomy guides instruct the surgeon to reference the ulnar axis with the elbow flexed at 90°. Average version values have been reported at 17.6° relative to the transepicondylar axis and 28.8° relative to the ulnar axis (Hernigou, Duparc, and Hernigou 2014), although it is highly variable and has been reported to range from 10° to 55° (Pearl and Volk 1999). These studies used 2D CT images; however, 2D has been shown to be unreliable for many glenohumeral measurements (Terrier 2015, Jacxsens 2015, Budge 2011). Three-dimensional (3D) modeling is now widely available and may improve the accuracy of version measurements. This study evaluated the effects of sex and measurement system on 3D version measurements made using the transepicondylar and ulnar axis methods, and additionally a flexion-extension axis commonly used in biomechanics. Methods. Computed tomography (CT) scans of 51 cadaveric shoulders (26 male, 25 female; 32 left) were converted to 3D models using medical imaging software. The ulna was reduced to 90° flexion to replicate the arm position during intra-operative version measurement. Geometry was extracted to determine landmarks and co-ordinate systems for the humeral long axis, epicondylar axis, flexion-extension axis (centered through the capitellum and trochlear groove), and ulnar long axis. An anatomic humeral head cut plane was placed at the head-neck junction of all shoulders by a fellowship trained shoulder surgeon. Retroversion was measured with custom Matlab code that analysed the humeral head cut plane relative to a reference system based on the long axis of the humerus and each elbow axis. Effects of measurement systems were analyzed using separate 1-way RM ANOVAs for males and females. Sex differences were analyzed using unpaired t-tests for each measurement system. Results. Changing the measurement reference significantly affected version (p<0.001). The ulnar axis method consistently resulted in higher measured version than either flexion-extension axis (males 9±1°, females 14±1°, p<0.001) or epicondylar axis (males 8±1°, females 12±1°, p<0.001). See Figure 1. Version in males (38±11°) was 7° greater than females (31±12°) when referencing the flexion-extension axis (p=0.048). Conclusion. Different measurement systems produce different values of version. This is important for humeral osteotomies; if version is assessed using the epicondyles pre-operatively and subsequently by the ulna intra-operatively, then the osteotomy will be approximately 10° over-retroverted. For any figures or tables, please contact authors directly (see Info & Metrics tab above).