[Autologous minced cartilage implantation for focal cartilage lesions of the humeral capitellum]. / Autologes Minced Cartilage bei fokalen Knorpelschäden des Capitulum humeri.

OBJECTIVE: The goal of minced cartilage implantation (MCI) is to restore an intact cartilage surface in focal osteochondral lesions of the humeral capitellum. INDICATIONS: The indications for MCI are limited osteochondral lesions at the humeral capitellum, also at the head of the radius, with intact cartilage border as well as in situ or a completely detached fragment, and free joint bodies (grade II-grade V according to Hefti). CONTRAINDICATIONS: Contraindications for MCI are already concomitant or associated cartilage damage as well as bilateral osteochondral lesions and insufficient available cartilage material. SURGICAL TECHNIQUE: After diagnostic arthroscopy to detect possible concomitant pathologies and to exclude already corresponding cartilage lesions, the arthroscope is flipped posterolaterally over the high posterolateral portal and a second portal is created under visualization via the soft spot. Initially, debridement of the focal cartilage defect, assessment of the marginal zone, and/or salvage of free joint bodies. Using a smooth shaver and the filter provided, the partially or even completely detached cartilage fragment is unidirectionally fragmented under continuous suction. The remaining defect with a stable marginal zone is cleanly curetted, and the joint is completely dried. The fragmented cartilage collected in the filter is bonded to a membrane using autologous conditioned plasma (ACP) and then arthroscopically applied to the defect via a cannula, sealed using thrombin and fibrin. POSTOPERATIVE MANAGEMENT: Postoperative immobilization in a cast for at least 24 h is required. Afterwards, free exercise of the joint is possible, but no loading should be maintained for 6 weeks. Return to sport after 3 months. RESULTS: Good to very good clinical and MRI morphologic results are already evident in the short-term course. Prospective and retrospective multicenter studies are needed to evaluate future long-term results.

[Central band reconstruction in Essex-Lopresti lesions]. / Rekonstruktion des Zentralen Bandes bei Essex-Lopresti-Verletzung.

OBJECTIVE: Restoration of longitudinal forearm stability by reconstruction of the central band (CB) of the interosseous membrane (IOM) of the forearm. INDICATIONS: Acute and chronic Essex-Lopresti lesions (EL) with longitudinal forearm instability. CONTRAINDICATIONS: Absolute: acute/subacute infection. Relative: severe complex regional pain syndrome (CRPS), bony deformity/bone loss, pronounced osteoarthritis of the elbow and wrist. SURGICAL TECHNIQUE: Ulnar approach with exposure of the ulna approximately 6 cm proximal to the ulnar styloid. Creation of a 3.5 mm drill hole from ulnar-distal to radial-proximal. A Fiberloop (Fa. Arthrex, Naples, FL, USA) is fixed to one end of the LARS (Ligament Advanced Reconstruction System, Fa. Corin Group, Cirencester, UK) in a whipstitch technique, is shuttled through the drill hole from radial to ulnar and fixed over a BicepsButton (Fa. Arthrex, Naples, FL, USA). Exposure of the radius through a modified Henry approach. A 3.5 mm drill hole is made from radial-proximal to ulnar-distal approximately 12 cm proximal to the radial styloid. The graft is shuttled from the ulnar to the radial incision directly on the palmar surface of the IOM and shortened to the required length. Another Fiberloop is used to perform a whipstitch on the free end of the LARS. The final fixation of the CB reconstruction is achieved by shuttling the Fiberloop sutures through the radial drill hole with fixation over a BicepsButton. POSTOPERATIVE MANAGEMENT: Short-term immobilization in a long arm cast with subsequent early functional treatment. RESULTS: Mediocre to poor clinical results are reported in the literature for the treatment of chronic EL. Future research will tell whether the advanced surgical techniques with CB reconstruction will lead to better clinical outcomes.

The Future of Total Elbow Arthroplasty: A Statistical Forecast Model for Germany.

This study provides a statistical forecast for the development of total elbow arthroplasties (TEAs) in Germany until 2045. The authors used an autoregressive integrated moving average (ARIMA), Error-Trend-Seasonality (ETS), and Poisson model to forecast trends in total elbow arthroplasty based on demographic information and official procedure statistics. They predict a significant increase in total elbow joint replacements, with a higher prevalence among women than men. Comprehensive national data provided by the Federal Statistical Office of Germany (Statistisches Bundesamt) were used to quantify TEA's total number and incidence rates. Poisson regression, exponential smoothing with Error-Trend-Seasonality, and autoregressive integrated moving average models (ARIMA) were used to predict developments in the total number of surgeries until 2045. Overall, the number of TEAs is projected to increase continuously from 2021 to 2045. This will result in a total number of 982 (TEAs) in 2045 of mostly elderly patients above 80 years. Notably, female patients will receive TEAs 7.5 times more often than men. This is likely influenced by demographic and societal factors such as an ageing population, changes in healthcare access and utilization, and advancements in medical technology. Our projection emphasises the necessity for continuous improvements in surgical training, implant development, and rehabilitation protocols.

[Elbow hemiarthroplasty for coronal shear fractures of the distal humerus]. / Ellenbogenhemiprothese bei koronaren Abscherfrakturen des distalen Humerus.

OBJECTIVE: The aim of the operation is to replace the articular surface of the distal humerus in cases of nonreconstructible fractures of the distal humerus. INDICATIONS: Active patients with high functional requirements, in whom weight limitation of total elbow arthroplasty should be avoided. CONTRAINDICATIONS: Contraindications include fractures with irreconstructible epicondyles and/or irreconstructible collateral ligaments, as well as ulnohumeral, or radiohumeral osteoarthritis. SURGICAL TECHNIQUE: Following subcutaneous anterior transposition of the ulnar nerve, surgical dislocation of the elbow joint is achieved through a paratricipital approach with release of the soft tissue structures from the humerus. After resection of the trochlea, the intramedullary canal of the humerus is prepared using rasps in order to implant the hemiprosthesis with retrograde cementing. Finally, the medial and lateral collateral ligaments as well as the flexors and extensors are repaired. POSTOPERATIVE MANAGEMENT: Early functional rehabilitation in a hinged elbow orthosis while avoiding varus/valgus stress after wound healing is completed. RESULTS: Between 2018 and 2022, 18 patients with coronal shear fractures were treated with elbow hemiarthroplasty. The mean Mayo Elbow Performance Score (MEPS) was 79 (70-95) after a mean follow-up of 12 months. The mean range of motion was 99° (70-130°) in extension-flexion and 162° (90-180°) in pronation-supination.

Evaluation of interleukin-6 in synovial fluid in periprosthetic joint infection of the elbow.

PURPOSE: Searching for quick determinable biomarkers with high sensitivity and specificity is necessary to improve and optimise the early diagnosis of periprosthetic elbow infection (PEI). Therefore, this study's objective was to evaluate the diagnostic value of synovial fluid interleukin-6 (IL-6) levels for diagnosing PEI in total elbow arthroplasty. METHOD: Twelve prospective enrolled patients underwent total elbow arthroplasty revision surgery, during which synovial fluid was obtained. Between the initial implantation and the revision procedure were 33.5 ± 41 months (range, 2-144 months). Synovial fluid was collected for immediate IL-6 analysis parallel to the revision surgery. Furthermore, microbiological samples were obtained and analysed. Two groups were defined based on the microbiological results: non-infection and infection group. The ability of synovial fluid IL-6 analysis to predict infection status was explored using receiver operating characteristic curves and further statistical analysis. RESULTS: Synovial fluid IL-6 analysis had a good diagnostic accuracy of 83% for PEI with an area under the curve of 0,79 and an ideal cutoff value (determined using Youden's criterion) of 15244 pg/mL. DISCUSSION: This is the first study to clinically evaluate IL-6 as a diagnostical marker for periprosthetic joint infection (PJI) in total elbow arthroplasty. Our results suggest a good accuracy and high sensitivity for IL-6 to identify a PEI. The analysis of IL-6 can improve surgical decision-making regarding managing total elbow arthroplasty in terms of one- or two-staged revision. CONCLUSION: IL-6 can play an important role in the perioperative differentiation of infected and non-infected situations.

Optimal Screw Orientation for Fixation of Coronal Shear Fractures: A Biomechanical Comparison.

OBJECTIVE: Coronal shear fractures of the capitellum are rare injuries which can be challenging to treat. The aim of this study was to compare the biomechanical properties of different internal screw fixation techniques for Dubberley type IA fractures of the capitellum. METHODS: In this biomechanical study, Dubberley type IA fractures of the capitellum were created in 30 human fresh-frozen humeri. The specimens were then divided into three groups: fixation was either performed with 3 x 3.0 mm headless cannulated compression screws (HCCSs) in anteroposterior (AP) orientation (AP group), 3 x 3.0 mm HCCSs in posteroanterior (PA) orientation (PA group) or with 2 x 3.0 mm HCCSs in PA orientation and 1 x 3.0 mm HCCS in lateral orientation (LAT group). Displacement under cyclic loading and ultimate load-to-failure were evaluated in all specimens. RESULTS: There was no significant difference in fragment displacement after 2000 cycles between AP and PA groups (0.8 ± 0.5 mm vs. 0.8 ± 0.6 mm; p = 0.987) or PA and LAT groups (0.8 ± 0.6 mm vs. 0.8 ± 0.3 mm; p = 0.966). LAT group showed the highest load-to-failure (548 ± 250 N) without reaching statistically significant difference to AP group (388 ± 173 N; p = 0.101). There was also no significant difference between AP and PA groups (388 ± 173 N vs. 422 ± 114 N; p = 0.649). CONCLUSIONS: Variations in screw placement had no statistically significant influence on cyclic displacement or load-to-failure in Dubberley Type IA fractures. However, fracture fixation in two planes - both the coronal and the sagittal plane - by adding a screw in a lateral to medial direction may be beneficial to increase primary stability.

How Preoperative Closed Reduction and Time to Surgery Impact Postoperative Palmar Inclination in Distal Radius Fractures.

Background: The anatomical reconstruction of the wrist is the aim when treating distal radius fractures. Current literature on the importance of preoperative reduction in fractures that are treated operatively is limited. Methods: This study investigated the effect of the preoperative closed reduction of distal radius fractures on the day of trauma and the time to surgery on postoperative palmar inclination. A total of eighty patients (48 females and 32 males, mean age 55.6 years) were studied retrospectively. All patients were treated with an open reduction and internal fixation. The palmar inclination angle was measured using X-rays by two investigators, and the interobservers and pre- and post-reduction parameters were compared. Results: When the surgical management of closed distal radius fractures is required, neither initial repositioning nor a delay of up to 14 days to the surgical treatment influences postoperative palmar inclination. Conclusions: The significance of preoperative reduction of distal radius fractures without neurovascular or extensive soft tissue damage is limited and is not leading to improved outcomes. When surgery is about to be performed, surgeons should carefully consider if reduction is really vital preoperatively. Level of evidence: III.

The importance of interdigitating screw fixation of the trochlea in double plate osteosynthesis of low transcondylar distal humerus fractures: A biomechanical study.

OBJECTIVE: The trochlea is of great importance for the stability of the elbow and its fixation in low transcondylar fractures of the distal humerus is especially challenging. The aim of this study was to determine the optimal trochlea fixation in double plate osteosynthesis of intraarticular distal humerus fractures. METHODS: A low transcondylar, C3-type distal humerus fracture was created in 20 fresh-frozen human cadaveric humeri. The samples were then randomly divided into two groups of 10 specimens each. Double plate osteosynthesis was performed in both groups. In group A, the two most distal screws of the lateral plate were inserted into the trochlea fragment. In group B, these screws did not extend into the trochlea. Displacement under cyclic loading and ultimate failure loads were determined for all specimens. RESULTS: Group A showed significantly less displacement under cyclic loading in each measurement interval (0.92 mm vs. 1.53 mm after 100 cycles, p = 0 0.006; 1.10 mm vs. 1.84 mm after 1000 cycles, p = 0.007; 1.18 mm vs. 1.98 mm after 2000 cycles, p = 0.008). The ultimate failure load was significantly higher in group A than in group B (345.61 ± 120.389 N vs. 238.42 ± 131.61 N, p = 0.037). CONCLUSIONS: Fixation of the trochlea with interdigitating screws in double plate osteosynthesis of low-condylar type C distal humerus fractures results in superior construct stability. LEVEL OF EVIDENCE: not applicable (biomechanical).

Unilateral Technique for Interposition Arthroplasty of the Elbow-A Technical Note.

Stiffness and pain secondary to end-stage dysfunctional osteoarthritis of the elbow can pose a therapeutic dilemma. Although total elbow arthroplasty is successful in older patients with low functional demand, alternatives to joint replacement must be found in the younger, more active individual. Interposition arthroplasty provides a salvage option for young, high-demand patients who hope to minimize functional restrictions of the affected extremity. The procedure traditionally involves release of both collateral ligaments and the joint capsule, resulting in a higher risk for postoperative instability and complications. The present unilateral technique demonstrates an approach maintaining the integrity of the medial or lateral collateral ligament while still allowing secure graft fixation. Stability can usually be preserved without ligament reconstruction or hinged external fixation if the elbow was stable before surgery.

Comprehensive analysis and classification of retrocondylar ulnar groove morphology using CT imaging in an average population of adults.

PURPOSE: Anatomical variations of the concave shaped retrocondylar ulnar groove (RUG) can contribute to ulnar nerve instability. However, there are currently limited available standardized data describing the anatomy of the RUG based on radiologic imaging, such as computed tomography (CT). This study aims to provide a comprehensive description and classification of RUG anatomy based on RUG angle measurements. METHODS: 400 CT scans of the elbows of adults showing no signs of osseous damage were evaluated. RUG angles were measured in four anatomically defined axial planes that spanned from the proximal to the distal end of the RUG. Furthermore, distance measurements at the medial epicondyle were conducted. A classification system for the RUG is proposed based on the acquired RUG angles, aiming to categorize the individual angles according to the 25th and 75th percentiles. RESULTS: RUG angles were significantly larger in males compared to females (p < 0.001) accompanied by larger distances including the off-set and height of the medial epicondyle (p < 0.001). RUG angles decreased from proximal to distal locations (p < 0.05). CONCLUSION: This study revealed that men exhibited larger RUG angles compared to women, indicating a less-concave shape of the RUG in men. Introducing an objective RUG classification system can improve our understanding of anatomical variations and potentially find application in diagnostics and preoperative planning.

Thumb Metacarpophalangeal Joint Kinematics and Elongation of the Ulnar Collateral Ligament.

PURPOSE: The purpose of the study was to determine if the sphericity of the thumb metacarpophalangeal (MCP) joint influences the joint's rotational axis (RA) and elongation patterns of the ulnar collateral ligament (UCL). METHODS: Ulnar collateral ligament origins and attachments of 28 fresh-frozen cadaveric thumbs were marked with a radiopaque marker. Lateral radiographs were obtained in neutral and 20°, 40°, and 60° of flexion. The dorsal and palmar joint gap and the length of four different UCL portions were digitally measured in all flexion states. The RA was determined by the intersection of the midshaft axis of the proximal phalanx in neutral and flexion states. Sphericity of the MCP joint was assessed using morphometric parameters. Joints were grouped as round or flat. Differences in all measured parameters between groups were analyzed. RESULTS: During flexion, the dorsal joint gap increased by 322% in flat joints and 163% in round joints. The palmar joint gap decreased to 45% in flat joints and to 87% in round joints. The RA was at 29% of metacarpal height and 96% of metacarpal length in flat joints and at 40% of height and 86% of length in round joints. Maximum UCL elongation (111%) was noted at 40° flexion in the dorsal proper UCL in flat joints and at 60° flexion in the accessory UCL (117%) in round joints. CONCLUSIONS: In flat MCP joints, the RA is more dorsal and distal in the metacarpal head compared to round joints, resulting in a hinged flexion motion. Elongation of the UCL is highest at end flexion in round joints and highest at midflexion in flat joints. CLINICAL RELEVANCE: The different kinematics of flat and round MCP joints may contribute to the understanding of the pathophysiology of UCL ruptures. The propensity of this injury and the position in which they occur may be affected by the MCP joint morphology.

Morphometrics of the coronoid process and the radial notch of the ulna: implications for fracture assessment.

PURPOSE: A comprehensive analysis of the morphology of fractures of the coronoid process (CP) can aid diagnosis and guide treatment. The involvement of the radial notch of the ulna (RN)-e.g., in anterolateral facet fractures and transverse fractures of the CP-may influence the biomechanical conditions of the proximal radioulnar joint. However, the morphometric relation between the CP and the RN and the extent to what the proximal radioulnar joint can be affected in these types of fractures is unknown. METHODS: A total of 113 embalmed, cadaveric ulnae were dissected. All soft tissue was removed. Strictly lateral, high-resolution photographs were taken and digitally analyzed. The height of the CP and its relation to the RN was measured. Sex differences and correlations between measured parameters were calculated. RESULTS: Mean height of the CP was 16 mm (range: 12-23 mm; SD: 2). Mean height of the RN was 16 mm (11-25 mm; 2.2). The 50% mark of the CP corresponded to 18% (0-56%; 11.2) of the height of the RN. No significant differences were found between male and female specimens. CONCLUSION: The RN of the ulna extends only to a small part to the CP. Transverse or anterolateral fractures of less than 50% of the coronoid process may involve only a small portion of the proximal radioulnar joint.

A combined experimental and finite element analysis of the human elbow under loads of daily living.

Elbow trauma is often accompanied by a loss of independence in daily self-care activities, negatively affecting patients' quality of life. Finite element models can help gaining profound knowledge about native human joint mechanics, which is crucial to adequately restore joint functionality after severe injuries. Therefore, a finite element model of the elbow is required that includes both the radio-capitellar and ulno-trochlear joint and is subjected to loads realistic for activities of daily living. Since no such model has been published, we aim to fill this gap. For comparison, 8 intact cadaveric elbows were subjected to loads of up to 1000 N, after they were placed in an extended position. At each load step, the displacement of the proximal humerus relative to the distal base plate was measured with optical tracking markers and the joint pressure was measured with a pressure mapping sensor. Analogously, eight finite element models were created based on subject-specific CT scans of the corresponding elbow specimens. The CT scans were registered to the positions of tantalum beads in the experiment. The optically measured displacements were applied as boundary conditions. We demonstrated that the workflow can predict the experimental contact pressure distribution with a moderate correlation, the experimental peak pressures in the correct joints and the experimental stiffness with moderate to excellent correlation. The predictions of peak pressure magnitude, contact area and load share on the radius require improvement by precise representation of the cartilage geometry and soft tissues in the model, and proper initial contact in the experiment.

The impact of the SARS-CoV-2 pandemic-related lockdowns on orthopedic trauma emergencies at a level-one trauma center.

INTRODUCTION: The SARS-CoV-2 pandemic and its associated lockdowns had a profound effect on orthopedic trauma emergencies. This study aimed to investigate the patient volume and injury patterns at a level-one trauma center during the SARS-CoV-2 pandemic and compare them to the pre-pandemic conditions. MATERIALS AND METHODS: A retrospective chart review of all patients who presented to the orthopedic trauma emergency department of a level-one trauma center in Cologne, Germany within a 2 year period from March 16th, 2019 to March 15th, 2020 (pre-pandemic control) and from March 16th, 2020 and March 15th, 2021 (pandemic) was performed. The pandemic year was separated into three periods: (1) first lockdown, (2) between lockdowns and (3) second lockdown. The absolute numbers of patient presentations, the Manchester triage score (MTS) and the relative proportion of patients with structural organ injuries, fractures and dislocations, of polytraumatized patients, of hospital admissions, of subsequent emergency or semi-elective surgeries and of work-related accidents were evaluated in comparison to the pre-pandemic control. RESULTS: A total of 21,642 patient presentations were included in this study. Significantly less weekly orthopedic trauma emergency patient presentations were recorded during the pandemic (p < 0.01). The MTS was significantly lower during the first lockdown and between lockdowns (p < 0.01). The proportional incidence of overall structural organ injuries, fractures and dislocations, of upper limb fractures/dislocations, of hospital admissions and of patients requiring surgery was significantly increased during the pandemic (p ≤ 0.03). The proportional incidence of work-related injuries was significantly decreased during the pandemic (p < 0.01). CONCLUSIONS: Orthopedic trauma emergency presentations were reduced during the SARS-CoV-2 pandemic. Due to the reluctancy of patients to visit the emergency department during the pandemic, the proportions of relevant injuries in general and of upper limb injuries in particular as well as of patients requiring hospital admission and trauma-related surgery were significantly increased.

[Follow-up treatment concepts for elbow injuries]. / Nachbehandlungskonzepte bei Ellenbogenverletzungen.

So far there are no clear recommendations for postoperative follow-up treatment of elbow injuries and individual concepts are often chosen. Due to the susceptibility for posttraumatic or postoperative impaired movement up to stiffness of the elbow joint, early mobilization plays a crucial role. Therefore, mid-term to long-term immobilization should be avoided. In addition to the necessary cryotherapy and compression therapy for swelling and pain control in the initial period, early actively assisted mobilization now has an important role. Additionally, active flexion and extension in an overhead position, so-called overhead motion, was recently established. After a short initial immobilization in a cast, mostly 3-5 days, the cast is changed to a dynamic movement orthosis, which when possible enables a free range of motion. Care is taken that varus and valgus loading is avoided. In general loading is avoided for the first 6 weeks, followed by a stepwise increase of loading up to maximum loading. In most cases return to sport is possible after 3 months. After implantation of an elbow prosthesis a maximum loading of 5 kg for single loading and 1 kg for repetitive loading are recommended.

[Monteggia-like injuries : Pitfalls of surgical treatment]. / Monteggia-like-Verletzungen : Pitfalls der operativen Versorgung.

The term Monteggia-like lesions or Monteggia equivalent injuries includes fractures of the proximal ulna with dislocation and dislocation fractures of the radial head from the proximal radio-ulnar joint. The complexity of the injury requires a dedicated understanding of the anatomical structures and their biomechanical properties. Particularly due to the rarity, the complication and revision rates are high. A conservative treatment is not usually effective. Three-dimensional imaging by computed tomography is part of the surgical preparation. The goal of surgical treatment is osteosynthetic reconstruction of the fractures and restoration of joint congruency. In cases of nonreconstructable radial head fractures, radial head arthroplasty may be necessary. In addition to reconstruction of the bony stabilizers, refixation of the ligamentous structures is essential for treatment success. The combination of complex fracture patterns and possible dislocation positions in the ulnohumeral, radiohumeral and proximal radio-ulnar joints poses a great challenge to the surgeon. The most frequent complications are peri-implant infections, implant failure, loss of reduction, stiffness or instability. Especially the anatomical configuration of the proximal ulna is complex and requires accurate reconstruction. Therefore, reconstruction of the proximal ulna in length and rotation, including the coronoid process, is considered to be a key factor in the surgical treatment of Monteggia-like injuries.

[Clinical results of total elbow arthroplasty after treatment failure for Monteggia-like injuries]. / Klinische Ergebnisse der Ellenbogentotalendoprothetik nach Therapieversagen bei Monteggia-like-Verletzungen.

BACKGROUND: Monteggia-like fractures (MLF) are complex injuries with high complication rates and frequently unsatisfying clinical results. Total elbow arthroplasty (TEA) represents the only option to salvage the functional requirements in some patients with pronounced posttraumatic arthropathy. This case series provides clinical results of TEA following failed treatment of MLF. METHODS: All patients who underwent TEA from 2017 to 2022 for failed treatment of MLF were retrospectively included in this study. Complications and revisions before and after TEA and functional results, measured by the Broberg/Morrey score, were evaluated. RESULTS: In this study 9 patients with a mean age of 68 (±7; 54-79) years were included. The mean follow-up was 12 (±9; 2-27) months. The main reasons leading to posttraumatic arthropathy were chronic infections (44.4%), bony instability due to coronoid deficiency (33.3%) or a combined coronoid and radial head deficiency (22.2%) and non-union of the proximal ulna with radial head necrosis (11.1%). The mean number of surgical revisions between primary fixation and TEA was 2.7 (±1.8; 0-6). The revision rate following TEA was 44%. The mean Broberg/Morrey score at the time of the latest follow-up was 83 (±10; 71-97) points. CONCLUSION: Chronic infection and coronoid deficiency are the main reasons for posttraumatic arthropathy after MLF leading to TEA. While the overall clinical results are satisfying, the indications should be reserved for selected cases due to high revision rates.

Thumb metacarpophalangeal joint morphology and reconstruction of the ruptured ulnar collateral ligament.

Studies on graft reconstruction techniques for ruptured thumb metacarpophalangeal (MCP) ulnar collateral ligaments (UCL) do not consider the variety of MCP joint morphology. Optimal reconstruction method for flat MCP joints is therefore unclear. Twenty-four fresh-frozen, human thumbs were tested for flexion, extension and valgus stability of the MCP joint. After resection of the UCL, four reconstruction methods, differing in the metacarpal origin and phalangeal attachment, were performed on each specimen, which were then tested again in the same way. Specimens were grouped as 'round' or 'flat' depending on morphometric parameters and group differences were analysed. In flat joints, only the non-anatomical Glickel reconstruction and a modified Fairhurst reconstruction maintained normal mobility and stability. In round joints, only the Glickel reconstruction maintained normal mobility and stability. The original Fairhurst method and a modification with the origin palmar in the metacarpus were disadvantageous in both flat and round joints.

Computed tomography-based angle measurements of the sagittal capitulum and trochlea position in relation to the humeral shaft.

The radiologic evaluation of the sagittal angulation of the distal humerus is commonly based on standard lateral radiographs. However, lateral radiographs do not allow to examine the lateral angulation of the capitulum and the trochlea, separately. Although this problem could be approached via computed tomography, there are no data available describing the difference between the angulation of the capitulum and trochlea. Therefore, we aimed to assess sagittal angles of the capitulum and trochlea in relation to the humeral shaft based on 400 CT-scans of the elbow in healthy adults. Angles were measured in sagittal planes at the capitulum center and three anatomically defined trochlea locations and were spanned between the axis of the joint component and the humerus shaft. Angles were tested for differences between measurement locations and correlation with patient characteristics (age, sex, trans-epicondylar distance). Angles increased from lateral to medial measurement locations (107.4 ± 9.6°, 167.4 ± 8.2°, 171.8 ± 7.3°, 179.1 ± 7.0°; p < 0.05). Largest angle differences were detected between the capitulum and trochlea with smallest angles measured at the capitulum. Patient characteristics did not correlate with angles (p > 0.05). Intra-rater-reliability was r = 0.79-0.86. As CT-imaging allows to distinguish between sagittal capitulum and trochlea locations, it might benefit the radiologic diagnostic of sagittal malalignments of the distal humerus at the capitulum and trochlea, separately.