[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.

[Technical modifications to elbow interposition arthroplasty]. / Technische Modifikation der Interpositionsarthroplastik des Ellenbogens.

OBJECTIVE: Interposition arthroplasty of the elbow involves the interposition of a fascia lata or dermis autograft or allograft between the distal humerus and the ulna or radius, while preserving the original form of articulation. INDICATIONS: Interposition arthroplasty is indicated for young patients with high functional demands who suffer from end-stage elbow arthritis and associated pain or joint stiffness. CONTRAINDICATIONS: Contraindications include acute or subacute infection, skeletal immaturity, bone loss, deformity, or gross instability. SURGICAL TECHNIQUE: Once the ulnar nerve has been secured, joint access is established via a posterior approach. The radial collateral ligament (RCL) and the common extensor tendon origin (CEO) are detached, while preserving the anconeus muscle and the lateral ulnar collateral ligament (LUCL). Subsequently, a capsular release is required to maintain adequate joint exposure and address the accompanying stiffness. Three to four transosseous drill holes are placed at the level of the distal humerus to secure the graft. After the graft has been positioned successfully within the joint space using two guide sutures, it can be secured to the distal humerus using a horizontal mattress stitch. Finally, the detached tendon and ligament structures are reconstructed. POSTOPERATIVE MANAGEMENT: After initial immobilization, early functional exercise of the elbow is performed in the motion orthosis, avoiding valgus or varus stress. RESULTS: The efficacy of elbow interposition arthroplasty has been demonstrated, particularly for young and active patients with severe inflammatory or post-traumatic osteoarthritis. Despite the results in terms of postoperative function and pain reduction are satisfactory, the current literature reports high complication, subsequent treatment, and revision rates. In the event of interposition arthroplasty failure, revision with another interposition procedure or conversion to endoprosthesis may be considered.

Early range of motion results in good elbow function following conservative treatment of non-displaced radial head fractures.

INTRODUCTION: The aim of this study was to evaluate the range of motion (ROM), elbow function and predictors for good elbow function after conservative treatment of non-displaced radial head fractures. MATERIAL AND METHODS: All patients with non-displaced radial head fractures (displacement < 2 mm), that were diagnosed between January 1st 2017 and December 31st 2021 in a level I trauma center, were included in this retrospective case series and the charts were evaluated for ROM and elbow function. Elbow function was categorized as "good" or "bad" depending on the ROM measured defined by Morrey et al. Overall, 73 patients (33 male, 40 female) with an average age of 38 years (+/- 13 years) could be included. RESULTS: Conservative treatment had good clinical results for ROM and elbow function. After 6 weeks mean flexion was 131° (SD 13°), extension 8° (SD 7°), Pronation 83° (SD 11°) and Supination 83° (SD 13). Patients with a good elbow function after one week showed a good elbow function after completing the treatment. CONCLUSIONS: A clinical assessment after one week should always be performed and the study showed that it is a good predictor for good elbow function. In cases of bad elbow function further controls should be considered.

Torque forces of expandable titanium vertebral body replacement cages during expansion and subsidence in the osteoporotic lumbar spine.

BACKGROUND: The application of expandable titanium-cages has gained widespread use in vertebral body replacement for indications such as burst fractures, tumors and infectious destruction. However, torque forces necessary for a satisfactory expansion of these implants and for subsidence of them into the adjacent vertebrae are unknown within the osteoporotic spine. METHODS: Six fresh-frozen human, osteoporotic, lumbar spines were dorsally instrumented with titanium implants (L2-L4) and a partial corpectomy of L3 was performed. An expandable titanium-cage was inserted ventrally and expanded by both residents and senior surgeons until fixation was deemed sufficient, based on haptic feedback. Torque forces for expansion were measured in Nm. Expansion was then continued until cage subsidence occurred. Torque forces necessary for subsidence were recorded. Strain of the dorsal rods during expansion was measured with strain gauges. FINDINGS: The mean torque force for fixation of cages was 1.17 Nm (0.9 Nm for residents, 1.4 Nm for senior surgeons, p = .06). The mean torque force for subsidence of cages was 3.1 Nm (p = .005). Mean peak strain of the dorsal rods was 970 µm/m during expansion and 1792 µm/m at subsidence of cages (p = .004). INTERPRETATION: The use of expandable titanium-cages for vertebral body replacement seems to be a primarily safe procedure even within the osteoporotic spine as torque forces required for subsidence of cages are nearly three times higher than those needed for fixation. Most of the expansion load is absorbed by straining of the dorsal instrumentation. Rod materials other than titanium may alter the torque forces found in this study.

Mayo classification of olecranon fractures revisited - Assessment of intra- and interobserver reliability based on CT scans.

Purpose: Olecranon fractures are classified using the commonly accepted Mayo classification. Its reliability has been analyzed by means of radiographs. A CT scan is often obtained due to joint involvement. Purpose of this study was to evaluate the intra- and interobserver reliability of the Mayo classification based on CT examination. Methods: Radiographic and CT images of 20 olecranon fractures were classified by four surgeons at two time points 30 days apart. Intra- and interobserver reliability were assessed using kappa coefficients. Results: Mean intraobserver reliability between X-rays was substantial and between CTs almost perfect (0.76 and 0.82, respectively). Mean interobserver reliability was fair for X-rays and moderate for CTs (0.32 and 0.44, respectively). Conclusion: Despite the more detailed imaging compared with radiography only moderate interobserver reliability was found for the classification of olecranon fractures based on CT imaging. This might lead to inconsistent fracture classification in both scientific and clinical setting.

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.

Intraoperative visualization of the posterolateral ulnohumeral joint space is reliable to indicate overlengthening in radial head arthroplasty.

INTRODUCTION: Avoiding overlengthening in radial head arthroplasty (RHA) is essential for the prognosis of the elbow joint. An overlengthening from 2 mm is visible due to widening of the anterolateral ulnohumeral joint space but intraoperatively, this particular joint space is difficult to visualize. The commonly used Kocher approach allows visualization of the posterolateral joint space without additional instruments or further surgical release of the already unstable elbow. The aim of our study was to investigate whether the visualization of the posterolateral joint space is also a reliable method to indicate overlengthening in RHA. MATERIAL AND METHODS: RHA was performed in five human cadaveric specimens with the forearm, wrist, and hand intact. The lateral ligament complex was detached and an anatomic transosseous refixation was performed. Six stages of implantation heights were documented: native joint (1), RHA at the anatomic height (2), + 2 mm (3), + 4 mm (4), + 6 mm (5) and - 2 mm (6). Macroscopic measurement and digital image analysis of the posterolateral and anterolateral ulnohumeral joint spaces were performed. RESULTS: All stages of overlengthening showed a significant increase in posterolateral and anterolateral joint space widening (p < 0.05). The posterior and anterior joint space showed excellent intraclass correlation. CONCLUSION: Visualization of the posterolateral aspect of the ulnohumeral joint space is a reliable indicator for overlengthening in RHA without further compromising an already unstable elbow. Correlation to the findings of the anterolateral ulnohumeral joint space in different implants leads to the assumption that visualization of either the anterior or posterior ulnohumeral joint space is universally applicable to determine overlengthening in RHA, regardless of the type of the radial head implant.

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.

Anteromedial coronoid facet fractures and associated ligament lesions: A case series.

INTRODUCTION: Varus posteromedial rotational injury mechanisms lead to fractures of the coronoids process' anteromedial facet. As these fractures are often unstable, rapid fracture treatment is vital to prevent progressive osteoarthritis. MATERIALS AND METHODS: Twelve patients with a fracture of the anteromedial facet treated surgically were enrolled in the study. Computed tomography images were used to classify the fractures according to the system by O'Driscoll et al. Clinical follow-up included each patient's medical record, surgical treatment algorithm, all complications encountered during the follow-up period, Disabilities of the arm, shoulder, and hand score, subjective elbow value, and pain. RESULTS: A total of 8 men (66.7%) and 4 women (33.3%) were treated surgically and followed-up after a mean period of 45 ± 23 months. The mean DASH score was 11.9 ± 12.9 points. One patient complained of transient neuropathy in the innervation area of the ulnar nerve, however, this existed already pre-operatively and resolved after less than three months. CONCLUSIONS: The presented patient cohort shows that AMF fracture of the coronoid process are unstable lesions according to the bony instability and the frequently ruptured collateral ligament complexes which need to be addressed. The MCL seems to be affected more frequently than previously appreciated. LEVEL OF EVIDENCE: Level IV; Case Series; Treatment Study.

Pedicle or lateral mass screws in Goel-Harms construct? A biomechanical analysis.

BACKGROUND: The use of the posterior arch of C1 as pedicle has shown beneficial stability regarding screw loosening, however, the C1 pedicle screw placement is challenging. Therefore, the study aimed to analyse the bending forces of the Harms construct used in fixation of C1/C2 when using pedicle screws compared to lateral mass screws. METHODS: Five cadaveric specimens with a mean age of 72 years at death and bone mineral density measuring for 512.4 Hounsfield Units (HU) on average were used. A custom-made biomechanical setup was used to test the specimens with a C1/C2 Harms construct each with the use of lateral mass screws and pedicle screws in sequence. Strain gauges were used to analyse the bending forces from C1 to C2 in cyclic axial compression (µm/m). All underwent cyclic biomechanical testing using 50, 75 and 100 N. FINDINGS: In all specimens, placement of lateral mass screws and pedicle screws was feasible. All underwent cyclic biomechanical testing. For the lateral mass screw, a bending of 142.04 µm/m at 50 N, 166.56 µm/m at 75 N and 188.54 µm/m at 100 N was measured. For the pedicle screws, bending force was slightly elevated with 165.98 µm/m at 50 N, 190.58 µm/m at 75 N and 195.95 µm/m at 100 N. However, bending forces did not vary significantly. In all measurements, no statistical significance was found when comparing pedicle screws and lateral mass screws. INTERPRETATION: The lateral mass screw used in the Harms Construct to stabilize C1/2 showed less bending forces, therefore the construct with lateral mass screws appears more stable in axial compression compared to the one with pedicle screws. However, bending forces did not vary significantly.

The simulation of terrible triad injuries in fresh-frozen human cadaveric specimens with intact soft tissue envelope.

INTRODUCTION: The aim of the present study was to develop a technical process to reproducibly generate terrible triad injuries (TTI) in fresh-frozen human cadaveric specimens, while leaving the skin intact. Such "pre-fractured" specimens, used for scientific analysis and for surgical education, might help to improve current treatment, which is complex and prone to complications. MATERIALS AND METHODS: To induce the desired fractures, a custom-made fracturing unit was used to apply an axial force on the extended cadaveric elbow specimens, with the forearm pronated and under valgus load. To simulate the valgus load, a pneumatic cylinder was developed to apply valgus stress to the joint by an additional force vector from the lateral side of the joint. RESULTS: The success rate of TTI induction was 92.3% (12/13). Of the 12 radial head fractures, 3 (25%) were classified Mason type II and 9 (75%) Mason type III. The coronoid fractures were grouped in tip subtype 2 (5 fractures, 41.7%), anteromedial facet (AMF) subtype 2 (4 fractures, 33.3%), AMF subtype 3 (1 fracture, 8.3%) and basal subtype 1 (2 fractures, 16.7%). CONCLUSIONS: The present study provides an instrument for successful and reproducible production of dislocation fracture patterns with their typical accompanying soft tissue lesions. The methodology might be applied on a broad basis to be able to perform biomechanical studies regarding primary stability of fixation concepts for TTI and to educate surgeons in a fairly realistic scenario with the surgical treatment of TTI.

Surgical arthrolysis of the stiff elbow: a systematic review.

INTRODUCTION: Stiffness after elbow injuries can severely limit daily life. If adequate conservative treatment does not result in satisfactory improvement of elbow function, surgical intervention should be considered. Whether an open or arthroscopic procedure is preferable is still a topic of debate and a systematic review of functional outcomes is lacking. MATERIALS AND METHODS: We systematically reviewed the available literature searching electronic databases, MEDLINE using the PubMed interface and EMBASE, for studies published between 2013 and 2021. Primary objective was to compare open and arthroscopic arthrolysis' functional outcomes, respectively, especially ROM and MEPS, as well as the accompanied complications. The PRISMA guidelines were applied. RESULTS: 27 studies comprising 1666 patients were included. 1059 patients (63.6%) were treated with open arthrolysis, and 607 patients (36.4%) were treated with arthroscopic arthrolysis. The results presented indicate satisfactory outcomes in open and arthroscopic arthrolysis with regard to functional outcome parameters. Treatment success, defined as excellent or good results according to the Mayo Elbow Performance Score, among the patients treated with an open procedure was 88.8%; 6.3% required revision whereas 18.1% had complications without the need for revision surgery. Within the cohort of arthroscopically treated patients, treatment success was 91.8%. Revisions and complications without further surgical intervention were significantly less frequent than in the open cohort, at 1.6% and 9.1%, respectively. CONCLUSIONS: Both open and arthroscopic arthrolysis provide good to excellent functional outcomes. Since the number of complications and revision increases with the invasiveness of the treatment, an arthroscopic procedure might be favored if feasible by indication. The role of forearm rotation and the use of a hinged external fixator remains of interest. STUDY DESIGN: Level IV; Systematic review.

The effect of long calcar screws on the primary stability of 3-part, varus impacted proximal humeral fractures compared to short calcar screws: a real fracture simulation study.

BACKGROUND: Complex proximal humeral fracture ranks among the most common fracture types, especially in elderly patients. In locked plate fixation of proximal humerus fractures, the calcar is deciding for screws providing further medial column support. To date, the biomechanical effect of the length of these calcar screws is not well known. The purpose of this study was to analyze the effect of long calcar screws on fresh frozen prefractured cadaveric specimens. METHODS: In the present biomechanical study, 8 pairs of cadaveric proximal humeri were fractured identically using a custom-made fracture simulator. ORIF was performed using a locking plate (PHILOS; Fa. Synthes). The specimens were tested in a biomechanical setup under increased axial load without any calcar screws installed, with short calcar screws and long calcar screws installed. Strain gages (4-wire-120 Ohm, Fa. Vishay) mounted on the locking plate were used to evaluate the fixation strain and to give an estimate for primary stability.. RESULTS: The measured strain of the locking plate without calcar screws (804,64 µm/m) at maximum load (200 N) was significantly higher than with short (619,07 µm/m; p = 0.02) or long calcar screws (527,31 µm/m; p = 0.007). Additionally, strain with short calcar screws was noticeably higher in comparison to long calcar screws (619,07 µm/m vs. 527,31 µm/m; p = 0.03). CONCLUSION: Use of calcar screws improves the stability of realistically impacted 3-part varus humeral fractures. Long calcar screws that are positioned as close as possible to the joint provide further primary stability compared to short calcar screws. LEVEL OF EVIDENCE: Basic science study.

Locking suture repair versus ligament augmentation-a biomechanical study regarding the treatment of acute lateral collateral ligament injuries of the elbow.

BACKGROUND: Lateral collateral ligament (LCL) tears are frequently observed in fractures and dislocations of the elbow. Recent biomechanical evidence suggests that additional ligament augmentation may improve repair stability. The aim of this biomechanical in-vitro study was to compare the resistance of a locking suture repair of the LCL with a ligament augmentation technique. MATERIAL AND METHODS: Eight fresh frozen cadaveric elbows were evaluated for stability against varus/posterolateral rotatory forces (3 Nm). A strain gauge (µm/m; negative values) was placed at the origin and insertion of the lateral ulnar collateral ligament (LUCL) and cyclic loading was performed for 1000 cycles. We analyzed three distinct scenarios: (A) native LCL, (B) locking transosseou suture repair of the LCL, (C) simple LCL repair with additional ligament augmentation of the LUCL. RESULTS: The mean measured strain was - 416.1 µm/m (A), - 618 µm/m (B) and - 288.5 µm/m (C) with the elbow flexion at 90°; the strain was significantly higher in scenario B compared to C (p = .01). During the cyclic load (1000) the mean measured strain was - 523.1 µm/m (B) and - 226.3 µm/m (C) with the elbow flexion at 60°; the strain was significantly higher in scenario B compared to C (p = .01). No significant difference between the first and the last cycles was observed (p = .09; p = .07). One failure of the LCL repair was observed after 1000 cycles; none of the ligament augmentations failed. CONCLUSION: Ligament augmentation (C) provides higher resistance compared to the native LCL (A) and to the locking suture repair technique (B). Both techniques, however, hold up during 1000 cycles. While ligament augmentation might enhance the primary stability of the repair, future clinical studies have to show whether this increase in resistance leads to negative effects like higher rates of posttraumatic elbow stiffness. LEVEL OF EVIDENCE: Basic science study, biomechanics.

Optimal K-Wire Placement for Indirect Cannulated Screw Fixation of Coronoid Process Fractures: A Radiology-Based Guide.

PURPOSE: Indirect fixation of coronoid process fractures of the ulna, especially arthroscopically, offers the possibility to avoid extensive medial surgical approaches. However, optimal placement of K-wires for cannulated screw fixation is technically challenging. The aim of the present study was to present guide values for K-wire placement for indirect screw fixation of coronoid tip (COT) and anteromedial facet (AMF) fractures of the ulna. METHODS: Computed tomography scans of the elbows of 197 patients with an uninjured ulna were identified and evaluated following a standard measuring protocol. Optimal placement of K-wires was defined as the bisector between the anterior and articular cortex while respecting a 1.6-mm safe zone for each placement. This placement of the K-wires in the COT and the AMF was analyzed by measuring the wire angulation in relation to the posterior ulnar cortex (AUC), the distance from the entry point to the posterior olecranon edge (DPE), and the intraosseous length (IOL). Because the coronoid has a curved shape, measurements of the COT and AMF were expected to differ significantly. Sex was also expected to influence measurements. To determine whether this optimal placement of K-wires can be reliably identified, interobserver and intraobserver reliabilities were evaluated. RESULTS: To address tip fragments, we determined a mean AUC of 64°, DPE of 36 mm, and IOL of 38 mm. Regarding wire placement toward the AMF, the means for the AUC, DPE, and IOL were 79°, 27 mm, and 33 mm, respectively. Statistically significant differences were found between the COT and the AMF for the AUC, DPE, and IOL. Our measuring protocol showed good interobserver and intraobserver reliability. CONCLUSIONS: K-wire placement toward the COT demands a smaller angle, a longer IOL, and a more distal entry point than wires placed toward AMF. These differences reflect the curved and complex anatomy of the coronoid. CLINICAL RELEVANCE: This measuring algorithm can be used to plan osteosynthesis, and the obtained reference values can help understand the coronoid's complex anatomy.