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.

Primary bone graft stability after Latarjet surgery: biomechanical evaluation of a fixation technique with metal-free all-suture cerclage vs. cortical screws

BACKGROUND

To reduce hardware-related complications in coracoid graft fixation to the anterior aspect of the glenoid, a metal-free Latarjet technique was recently introduced. The aim of this study was to compare the primary stability of a classic Latarjet procedure with 2 metal screws to a novel metal-free, all-suture cerclage method. It is hypothesized that fixation of the coracoid graft with 2 malleolar screws will provide higher primary stability compared with an all-suture cerclage technique.

METHODS

This biomechanical in vitro study was conducted on 12 fresh-frozen cadaveric shoulders (6 matched pairs) with a mean donor age of 80 years (range, 67-89 years). Coracoid graft fixation was performed using a recently introduced all-suture cerclage technique (group A) or a classic Latarjet technique with two 4.5-mm malleolar screws (group B). The conjoint tendon was loaded with a static force of 10 N to simulate the sling effect. Graft loading with a probe head consisted of 6 ascending load levels (10-50 N, 10-100 N, 10-150 N, 10-200 N, 10-250 N, and 10-300 N) with 100 cycles each at 1 Hz. Relative motion of the bone graft to the glenoid was measured using an optic 3-dimensional system.

RESULTS

While loading the conjoint tendon with 10 N, no difference in mean displacement of the bone-graft was found between both groups (P = .144). During cyclic loading, a significant difference in relative displacement for both groups was already detected in load level 1 (group A: 2398.8 μm vs. group B: 125.7 μm; P = .024), and this trend continued with the following load levels (P < .05).

DISCUSSION AND CONCLUSION

The study demonstrated that the innovative metal-free, all-suture cerclage fixation technique results in higher micromotion than the classic coracoid graft fixation with 2 malleolar screws. According to the present biomechanical investigation, shoulders treated with a metal-free all-suture cerclage technique might need adapted rehabilitation protocols to protect the construct and allow for graft healing.

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).

Accessibility of osteochondral lesion at the capitellum during elbow arthroscopy: an anatomical study

INTRODUCTION

Osteochondrosis dissecans (OCD) at the capitellum is a common pathology in young patients. Although arthroscopic interventions are commonly used, there is a lack of information about the accessibility of the defects during elbow arthroscopy by using standard portals.

MATERIALS AND METHODS

An elbow arthroscopy using the standard portals was performed in seven fresh frozen specimens. At the capitellum, the most posterior and anterior cartilage surface reachable was marked with K-wires. Using a newly described measuring method, we constructed a circular sector around the rotational center of the capitellum. The intersection of K-wire "A" and "B" with the circular sector was marked, and the angles between the K-wires and the Rogers line, alpha angle for K-Wire "A" and beta angle for K-wire "B", and the corridor not accessible during arthroscopy was digitally measured.

RESULTS

On average, we found an alpha angle of 53° and a beta angle of 104°. Leaving a sector of 51° which was not accessible via the standard portals during elbow arthroscopy.

CONCLUSION

Non-accessible capitellar lesions during elbow arthroscopy should be considered preoperatively, and the informed consent discussion should always include the possibility of open procedures or the use of flexible instruments.

LEVEL OF EVIDENCE: 4

Distal Triceps Rupture with an Injury of the Medial Ulnar Collateral Ligament: a Result of a Fall Onto an Outstretched Arm - a Case Series

Traumatic triceps tendon ruptures are rare and known to result in substantial disability unless appropriate surgical treatment is performed. A traumatic rupture can occur due to a fall onto the outstretched hand. Tearing of the triceps tendon results in a valgus load onto the elbow, which can lead to injuries to the radial head/neck and/or the ulnar collateral ligament. Hence, attention must be paid to associated pathologies after diagnosis of rupture to the distal triceps tendon. Our surgical procedure in these cases includes diagnostic arthroscopy to detect concomitant injuries. In the following, we present three cases where we performed an open suture bridge repair of the triceps tendon followed by suture repair of the ulnar collateral ligament. All patients recovered well and reported no elbow pain or limited range of motion. The ASES and Mayo Elbow Performance scores were 100 at the 1-year follow-up.

Do We Need a Strictly Lateral Radiograph for Fracture Management of Forearm Buckle Fractures in Children?

OBJECTIVES

Buckle fractures of the distal forearm are a common fracture entity in children treated conservatively. Diagnostics primarily include radiographs in 2 planes. Inadequate images may occur in the mostly very young patients. Therefore, additional lateral radiographs are often obtained to assess a possible angular tilt. The aim of this study is to investigate whether a strictly lateral x-ray image has an influence on fracture management.

METHODS

Seventy-three children with buckle fractures of the distal forearm were included in this retrospective analysis. All cases were analyzed by quality of radiographs, necessity to obtain an additional lateral radiograph, and what influence on fracture management resulted. Follow-up was performed 2 to 4 weeks after immobilization.

RESULTS

Thirty-five girls and 38 boys with a mean age of 7.16 years were included; 40 had fractured right and 33 had fractured left arms, respectively. Isolated distal radius fractures occurred in 48 cases, isolated distal ulna fractures in 6 cases, and both bones in 19 cases. Initial radiographic images were evaluated as inadequate in 25 cases. In each of those cases, an additional lateral image was obtained by fluoroscopy without resulting in an alternated fracture management protocol, which was chosen conservatively in each case and resulted in excellent clinical outcome at follow-up examination.

CONCLUSIONS

Based on our results, the acquisition of additional lateral radiographs seems to be unnecessary in the diagnostic procedure of buckle fractures of the distal forearm, in case a possible palmar or dorsal angulation cannot be entirely assessed on the initial set of radiographs. An additional lateral image had no influence on fracture management, which was chosen conservatively in every case and led to excellent clinical results.Level of evidence: level III.

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.

Postoperative swelling after elbow surgery: influence of a negative pressure application in comparison to manual lymphatic drainage-a randomized controlled trial

PURPOSE

Postoperative soft tissue swelling is a significant factor influencing outcomes after elbow surgery. It can crucially affect important parameters such as postoperative mobilization, pain, and subsequently the range of motion (ROM) of the affected limb. Furthermore, lymphedema is considered a significant risk factor for numerous postoperative complications. Manual lymphatic drainage is nowadays part of the standardized post-treatment concept, basing on the concept of activating the lymphatic tissue to absorb stagnated fluid from the tissue into the lymphatic system. This prospective study aims to investigate the influence of technical device-assisted negative pressure therapy (NP) on early functional outcomes after elbow surgery. NP was therefore compared to manual lymphatic drainage (MLD). Is a technical device-based NP suitable for treatment of lymphedema after elbow surgery?

METHODS

A total of 50 consecutive patients undergoing elbow surgery were enrolled. The patients were randomized into 2 groups. 25 participants per group were either treated by conventional MLD or NP. The primary outcome parameter was defined as the circumference of the affected limb in cm postoperative up to seven days postoperatively. The secondary outcome parameter was a subjective perception of pain (measured via visual analogue scale, VAS). All parameters were measured on each day of postoperative inpatient care.

RESULTS AND CONCLUSION

NP showed an overall equivalent influence compared to MLD in reducing upper limb swelling after surgery. Moreover, the application of NP showed a significant decrease in overall pain perception compared to manual lymphatic drainage on days 2, 4 and 5 after surgery (p <  0.05).

CONCLUSION

Our findings show that NP could be a useful supplementary device in clinical routine treating postoperative swelling after elbow surgery. Its application is easy, effective and comfortable for the patient. Especially due to the shortage of healthcare workers and physical therapists, there is a need for supportive measures which NP could be.

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.

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.

Screw placement in arthroscopically assisted osteosynthesis of radial head fractures using a reference k-wire in the radiocapitellar joint: a cadaveric study

PURPOSE

The optimal screw placement in arthroscopically assisted fixation of radial head fractures is still an issue and no guiding methods have been evaluated in the recent literature. The study hypothesis was that using a "reference k-wire" percutaneously inserted in and parallel to the radiocapitellar joint would enable to achieve a trajectory more parallel to the radial head articular surface as compared to a free-hand k-wire placement.

METHODS

Arthroscopically assisted placement of a k-wire in the radial head was performed in seven fresh-frozen human cadaver specimens by three surgeons. Three different techniques were evaluated: freehand drilling (technique A), placement using a "reference" k-wire in the radiocapitellar joint as a reference without (technique B), and with the AO parallel k-wire guide (technique C). Radiographs from all procedures were obtained and the inclination angle "α" between the k-wire and the articular surface of the radial head was measured and compared among the techniques.

RESULTS

Angles of 84 radiographs were obtained and showed a mean α angle of 30.1° ± 13° for technique A, 5.7° ± 4.5° for technique B, and 5.4° ± 3.7° for technique C. The angle α was significantly higher with technique A as compared to B (p < 0.0001) and C (p < 0.0001). There was no difference between methods B and C (n.s.). No difference was observed among the surgeons for all three methods (p = 0.66).

CONCLUSION

With the use of an additional "reference" k-wire placed in the radiocapitellar joint, the guiding k-wire for screw drilling can be placed almost parallel to the radial head joint line with limited variability and a good reproducibility during arthroscopically assisted radial head fracture fixation.

CLINICAL RELEVANCE

The here-presented method of an additional, percutaneous introduced "reference" k-wire is easily applicable and helpful to achieve parallel screw placement during arthroscopically assisted radial head fracture fixation.

LEVEL OF EVIDENCE

IV, biomechanical cadaver study.

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.

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.

Correlation of head screw lengths in proximal humerus nailing: a CT-based study on 289 cases

INTRODUCTION

Nailing of the proximal humerus is an established method for the treatment of proximal humerus fractures. Choice of the correct length for potentially four proximal locking screws is essential for postoperative outcome. Due to positioning of the patient, intraoperative determination of the correct length of the anteroposterior (AP) screw with the x-ray beam is particularly challenging even for experienced surgeons. We hypothesized that there would be a correlation between the projected lengths of the different proximal locking screws and therefore the length of the AP-screw could be determined based on the three lateromedial (LM) screws.

MATERIALS AND METHODS

In this retrospective study (level of evidence: III) CT-scans of shoulders of 289 patients were 3D reconstructed with the program Horos. Using the manufacturer Stryker's instructions, the four proximal locking screws of the T2 Humeral Nail system were reproduced in the 3D reconstructed shoulders. The length of the AP-screw was correlated with the lengths of the LM-screws by Linear Regression and Multiple Linear Regression.

RESULTS

The results of this study showed that the lengths of proximal locking screws in proximal humeral nailing correlated significantly with each other. Based on the given data, a formula could be established to calculate the length of the AP-screw based on the lengths of the LM-screws with a probability of 76.5%.

CONCLUSIONS

This study was able to show that the length of the AP-screw could be determined from the intraoperatively measured lengths of the LM-screws. As our findings base on measurements performed in CT scans, clinical studies are needed to support our data.

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.

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.

Is the rod necessary? Biomechanical comparison of static knee spacers during axial loading

BACKGROUND

Knee Spacers are required in two-stage revision surgery of periprosthetic joint infection of the knee. Extended bone and ligamentous defects are often temporarily arthrodised via a static spacer. Regarding their weight-bearing potential and construction, there is no current consent. Our aim was to evaluate three individual static spacer variants with regard to their axial loading capacity.

METHODS

The static spacer variants were tested in a cadaver model. One after the other, a spacer with metal-reinforced rods, a spacer without metal reinforcement and a rod-less spacer were implanted and tested up to an axial loading of 1000 Newton. Target parameters were plastic deformation, stiffness and spacer movement at both the femoral and tibial surface. Loading was applied up to 1000 Newton. Radiological controls of the bone substance were performed.

FINDINGS

The spacer variants did not differ regarding deformation, stiffness or spacer movement. However, deformation increased significantly with the axial load in all spacer variants. Radiographs showed no fracture or spacer-dislocation resulting from testing.

INTERPRETATION

While the spacer reinforcement or the sheer presence of a rod did not influence the axial loading capacity in this in vitro study, weightbearing should be discouraged to limit further bone erosion.

The automized fracture edge detection and generation of three-dimensional fracture probability heat maps

With proven impact of statistical fracture analysis on fracture classifications, it is desirable to minimize the manual work and to maximize repeatability of this approach. We address this with an algorithm that reduces the manual effort to segmentation, fragment identification and reduction. The fracture edge detection and heat map generation are performed automatically. With the same input, the algorithm always delivers the same output. The tool transforms one intact template consecutively onto each fractured specimen by linear least square optimization, detects the fragment edges in the template and then superimposes them to generate a fracture probability heat map. We hypothesized that the algorithm runs faster than the manual evaluation and with low (< 5 mm) deviation. We tested the hypothesis in 10 fractured proximal humeri and found that it performs with good accuracy (2.5 mm ± 2.4 mm averaged Euclidean distance) and speed (23 times faster). When applied to a distal humerus, a tibia plateau, and a scaphoid fracture, the run times were low (1-2 min), and the detected edges correct by visual judgement. In the geometrically complex acetabulum, at a run time of 78 min some outliers were considered acceptable. An automatically generated fracture probability heat map based on 50 proximal humerus fractures matches the areas of high risk of fracture reported in medical literature. Such automation of the fracture analysis method is advantageous and could be extended to reduce the manual effort even further.

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.

[Elbow prosthesis after acute fractures : Indications and technique]

Good to very good clinical results can be achieved in older patients with the implantation of a total elbow prosthesis in cases of distal humeral fractures by taking the morphological features of the fractures, the bone quality as well as the individual patient requirements and variables into account. The most commonly used design is the cemented semiconstrained linked total elbow endoprosthesis. The unlinked prosthesis design and hemiarthroplasty require intact or adequately reconstructable musculoligamentous structures or condyles and a preserved or replaced radial head. The recommended weight limit after total elbow prosthesis as well as potential intraoperative and postoperative complications must be considered and discussed with the patients. A secondary total elbow arthroplasty is also possible after primary conservative treatment approaches, e.g., in the case of contraindicated surgery in the fracture situation, persistent pain and functional restrictions. This article provides an overview of the technique and the appropriate indications.

Focus on stability: biomechanical evaluation of external fixation technique versus locking plate osteosynthesis in 3-part proximal humeral fractures

BACKGROUND

The purpose of this study was to investigate the primary stability and displacement tendencies of an external fixation system in 2 different configurations in comparison to locking plate fixation in a 3-part proximal humeral fracture model.

METHODS

Twenty-one fresh-frozen human cadaveric proximal humeral specimens were divided into 3 groups of 7 stripped specimens. An unstable 3-part fracture of the proximal humerus was set. Construct A consisted of the Galaxy Fixation Shoulder System, with fixation in accordance with the manufacturer's recommended technique (3 pairs of threaded wires). Construct B was fixed with an additional pair of threaded wires according to the recommendations of Gumina et al (4 pairs of threaded wires). The remaining 7 specimens were fixed with a locking plate. By use of an optical motion capture system, relative motion at the fracture site and failure load were evaluated during a cyclic loading protocol.

RESULTS

Plate osteosynthesis showed the highest cyclic load to failure (895 ± 239 N; range, 597-1135 N), followed by construct B (692 ± 121 N; range, 432-788 N) and construct A (350 ± 190 N; range, 139-615 N). Statistically significant differences were found between plating and construct A (P < .001), between plating and construct B (P = .031), and between construct B and construct A (P = .013). Relative motion at the fracture site, in terms of change in distance during cyclic loading, was lowest with construct B measured at the peak load of 395 N after 11 steps (1.73 ± 1.98 mm; range, 0.53-5.96 mm) and highest with construct A (8.46 ± 10.67 mm; range, 2.26-20.79 mm). Angular change measured at the peak load after 11 steps was lowest with construct B (1.19° ± 0.36°; range, 0.59°-1.7°) and highest with construct A (2.44° ± 1.63°; range, 0.77°-4.04°). Statistically significant differences were found between construct A and construct B and between construct A and plating at various steps of cyclic loading.

CONCLUSION

In this biomechanical study of unstable 3-part proximal humeral fractures, locking plate osteosynthesis demonstrated the highest possible load application. External fixator application with 8 threaded wires (construct B) revealed the least relative motion at the fracture site, without a statistically significant difference compared with locking plates. It therefore represents another valid technique for treatment regarding primary stability. The use of external fixator application with 6 threaded wires (construct A) resulted in the lowest stability and the highest rates of displacement.

Trans-fracture approach for ORIF of coronal shear fractures of the distal humerus

INTRODUCTION

Open reduction and internal fixation (ORIF) of comminuted coronal shear fractures of the distal humerus is challenging. When a concomitant lateral condyle fracture is present, it may be used for a trans-fracture approach to facilitate exposure and fracture reduction. This study aimed to investigate the frequency of lateral condyle fractures in coronal shear fractures of the distal humerus and analyze fracture reduction, fracture union and clinical results following ORIF through a trans-fracture approach.

MATERIALS AND METHODS

All adult patients who underwent treatment for an acute distal humerus fracture during a three-year period in our level-one trauma center were identified. All fractures were classified according to the Orthopaedic Trauma Association (OTA/AO) fracture classification system and all B3 fractures were classified according to the Dubberley classification. B3 fractures with a concomitant radial condyle fracture were identified. The clinical and radiological results, (Mayo Elbow Performance Score = MEPS, Visual Analogue Scale = VAS, range of motion), complications and revision surgeries were analyzed.

RESULTS

53 patients (mean age 52 ± 19 years) were identified. 13 fractures (24.5%) were B3 fractures. Four of them (30.8%) had a concomitant radial condyle fracture. All of these patients underwent ORIF with headless cannulated compression screws and a (postero-)lateral locking plate through a trans-fracture approach. At a minimum follow-up of 24 months, the MEPS was 88 ± 12 points, the VAS was 2 ± 1 and the range of motion was 118° ± 12°. All fractures showed anatomic reduction. One patient developed partial avascular necrosis and underwent arthrolysis at 6 months. One patient underwent partial hardware removal and lateral collateral ligament bracing at 6 months.

CONCLUSIONS

Lateral condyle fractures are present in about one third of coronal shear fractures of the distal humerus. This injury can be used for a trans-fracture approach to facilitate exposure and to reliably achieve anatomic fracture reduction.

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.

Influence of rotator cuff preload on fracture configuration in proximal humerus fractures: a proof of concept for fracture simulation

INTRODUCTION

In regard of surgical training, the reproducible simulation of life-like proximal humerus fractures in human cadaveric specimens is desirable. The aim of the present study was to develop a technique that allows simulation of realistic proximal humerus fractures and to analyse the influence of rotator cuff preload on the generated lesions in regards of fracture configuration.

MATERIALS AND METHODS

Ten cadaveric specimens (6 left, 4 right) were fractured using a custom-made drop-test bench, in two groups. Five specimens were fractured without rotator cuff preload, while the other five were fractured with the tendons of the rotator cuff preloaded with 2 kg each. The humeral shaft and the shortened scapula were potted. The humerus was positioned at 90° of abduction and 10° of internal rotation to simulate a fall on the elevated arm. In two specimens of each group, the emergence of the fractures was documented with high-speed video imaging. Pre-fracture radiographs were taken to evaluate the deltoid-tuberosity index as a measure of bone density. Post-fracture X-rays and CT scans were performed to define the exact fracture configurations. Neer's classification was used to analyse the fractures.

RESULTS

In all ten cadaveric specimens life-like proximal humerus fractures were achieved. Two III-part and three IV-part fractures resulted in each group. The preloading of the rotator cuff muscles had no further influence on the fracture configuration. High-speed videos of the fracture simulation revealed identical fracture mechanisms for both groups. We observed a two-step fracture mechanism, with initial impaction of the head segment against the glenoid followed by fracturing of the head and the tuberosities and then with further impaction of the shaft against the acromion, which lead to separation of the tuberosities.

CONCLUSION

A high energetic axial impulse can reliably induce realistic proximal humerus fractures in cadaveric specimens. The preload of the rotator cuff muscles had no influence on initial fracture configuration. Therefore, fracture simulation in the proximal humerus is less elaborate. Using the presented technique, pre-fractured specimens are available for real-life surgical education.

LEVEL OF EVIDENCE

III.

Anatomic evaluation of the triceps tendon insertion at the proximal olecranon regarding placement of fracture fixation devices

PURPOSE

Olecranon fractures, especially with a small proximal fragment, remain a surgical challenge. Soft tissue irritation and affection of the triceps muscle bear a risk of complications. In order to find an area for a soft-tissue sparing placement of implants in the treatment of olecranon fractures, we aimed to define and measure the segments of the proximal olecranon and evaluate them regarding possible plate placement.

METHODS

We investigated 82 elbow joints. Ethical approval was obtained from the local ethics committee, After positioning in an arm holder and a posterior approach we described the morphology of the triceps footprint, evaluated and measured the surface area of the triceps and posterior capsule and correlated the results to easily measurable anatomical landmarks.

RESULTS

We found a bipartite insertional footprint with a superficial tendinous triceps insertion of 218.2 mm² (± 41.2, range 124.7-343.2), a capsular insertion of 159.3 mm² (± 30.2, range 99.0-232.1) and a deep, muscular triceps insertion area of 138.1 mm² (± 30.2, range 79.9-227.5). Olecranon height was 26.7 mm (± 2.3, range 20.5-32.2), and olecranon width was 25.3 mm (± 2.4, range 20.9-30.4). Average correlation between the size of the deep insertion and ulnar (r = 0.314) and radial length (r = 0.298) was obtained.

CONCLUSIONS

We demonstrated the bipartite morphology of the distal triceps footprint and that the deep muscular triceps insertion area by its measured size could be a possible site for the placement of fracture fixations devices. The size correlates with ulnar and radial length.

Distal humerus fracture in patients over 70 years of age: results of open reduction and internal fixation

BACKGROUND

Due to the complexity of distal humerusfractures and often poor bone quality in elderly patients, these entities remain a challenge. However, because of a high rate of complications related to total elbow prostheses, reconstruction of distal humerus fractures should still be considered a therapeutic option, also in the elderly patient. The purpose of the present study was to investigate the clinical outcomes after open reduction and internal fixation and to evaluate whether the results justify reconstruction even in elderly patients. We hypothesized that despite advanced age, reasonable clinical results can be achieved, using a standardized surgical technique and aftertreatment protocol for the treatment of distal humerus fractures in elderly patients.

METHODS

Between 2004 and 2012, 30 patients with a mean age of 78 years at the time of injury with a recent distal humerus fracture were evaluated. All patients underwent the identical aftertreatment protocol with no weight bearing for 6 weeks and weekly increasing range of motion. Follow-up rate was 90%. 22 patients were treated with double plate, 4 with single plate, and 1 with screw fixation only. Patients were evaluated based on clinical criteria. Primary outcome measures were Mayo Elbow Performance Score, VAS and joint range of motion, secondary was radiological evaluation.

RESULTS

After a mean follow-up period of 3.8 years (min. 1 year, max. 9 years, SD ± 2), the average range of motion was flexion of 127° (min. 100°; max. 150°; SD ± 16.5) and average loss of extension of 20.9° (min. 5°; max. 40°; SD ± 11). Average pronation and supination was 68.3° (min. 0°; max. 90°; SD ± 25.3) and 75.3° (min. 0°; max. 90°; SD ± 19.7), respectively. Average Mayo Elbow Performance (MEPS) score was 88.7 (min. 60; max. 100; SD ± 12.1). 6 patients developed heterotopic ossification without significant effect on the clinical outcome. 7 patients had radiological evidence of at least partial non-union with one requiring revision, 2 discrete hardware dislocations were treated conservatively. There were no infections in the presented cohort. Our results regarding the surgical approach showed significantly higher patient satisfaction scores in the osteotomy group, compared to the group with Triceps-On Approach (PTOA).

CONCLUSION

The present data support indication for open reduction internal fixation (ORIF) even in the elderly patient. Advanced age should not be seen as a contraindication for ORIF of fractures of the distal humerus. Although the rate of complications is higher than in younger patients, complications such as non-union are often asymptomatic, patient satisfaction scores are high, and the possible devastating complications of failed elbow replacement can be evaded.

LEVEL OF EVIDENCE

IV.

"Crack under pressure"-Inducing life-like mandible fractures as a potential benefit to surgical education in oral and maxillofacial surgery

The aim of this study was to investigate whether life-like fractures of human cadaveric mandibles with a focus on the condylar process and the intact soft tissue envelope could be simulated. A total of nine fresh-frozen human head specimens were fractured in a custom-made drop-test bench. This reproducible method is based on a weight falling from a defined height onto the fixed specimens, simulating a direct blow to the symphysis of the mandible. All the fractures were analyzed by fluoroscopy and CT-scans. In all the specimens that were included in this study, several typical lesions could be created, resulting in a total of 27 mandible fractures. Seven condylar head fractures with intracapsular fracture patterns, three high, two low and five subcondylar fractures as well as different corpus fractures occurred. Human cadaveric mandibles as part of a complete head specimen with intact soft tissue can be successfully fractured by means of a drop-test bench setup. The amount of load and the exact angle at which the load is applied seem to be of high relevance. Such fractured specimens can be implemented in surgical education courses to teach and improve osteosynthetic techniques.

A biomechanical analysis of different meshes for reconstructions of the pelvic floor in the porcine model

Purpose

Many different surgical approaches have been established for the repair of a pelvic organ prolapse. Especially in laparoscopic surgery, it is important to generate easy surgical techniques with similar stability. This study shall simplify the choice of mesh by evaluating three polypropylene meshes regarding their biomechanical properties.

Methods

Biomechanical testing was performed in the porcine model. The meshes are fixated on porcine fresh cadaver cervices after subtotal hysterectomy. The apical part of the mesh is fixated with parallel screw clamps at the testing frame. Forty-one trials were performed overall, subdivided into four subgroups. The groups differ in mesh type and fixation method. Maximum load, displacement at failure and stiffness parameters were evaluated with an Instron 5565^® test frame.

Results

SERATEX^® E11 PA (E11) showed the highest values for maximum load (199 ± 29N), failure displacement (71 ± 12 mm) and stiffness (3.93 ± 0.59 N/mm). There was no significant difference in all three evaluated parameters between SERATEX^® B3 PA (B3) and SERATEX^® SlimSling^® with bilateral fixation (SSB). SERATEX^® SlimSling^® with unilateral fixation (SSU) had the lowest stiffness (0.91 ± 0.19 N/mm) and maximum load (30 ± 2 N) but no significant difference in displacement at failure.

Conclusion

All meshes achieved a good tensile strength, but the results of maximum load show that the E11 is superior to the other meshes. Through a bilateral fixation of SERATEX^® SlimSling^®, a simple operating method is generated without a loss of stability.

Tacks vs. sutures: a biomechanical analysis of sacral bony fixation methods for laparoscopic apical fixations in the porcine model

Purpose

There is a novel surgical procedure, called cervicosacropexy (CESA) and vaginosacropexy (VASA) to treat pelvic organ prolapse and a concomitant urgency and mixed urinary incontinence. As there is little experience with the tapes so far and literature is scanty, the aim of this study was to investigate biomechanical properties for the fixation of the PVDF-tapes with three different fixation methods in context of apical fixations.

Methods

Evaluation was performed on porcine, fresh cadaver sacral spines. A total of 40 trials, divided into 4 subgroups, was performed on the anterior longitudinal ligament. Recorded biomechanical properties were displacement at failure, maximum load and stiffness in terms of the primary endpoints. The failure mode was a secondary endpoint. Group 4 was a reference group to compare single sutures on porcine tissue with those on human tissue. Biomechanical parameters for single sutures on the human anterior longitudinal ligament were evaluated in a previous work by Hachenberg et al.

Results

The maximum load for group 1 (two single sutures) was 65 ± 12 N, for group 2 (three titanium tacks arranged in a row) it was 25 ± 10 N and for group 3 (three titanium tacks arranged in a triangle) it was 38 ± 12 N. There was a significant difference between all three groups. The most common failure mode was a “mesh failure” in 9/10 trials for groups 1–3.

Conclusion

The PVDF-tape fixation with two single sutures endures 2.6 times more load than titanium tacks arranged in a row and 1.7 times more load than titanium tacks arranged in a triangle. The presacral fixation with titanium tacks reduced surgical time compared to the fixation with sutures, nevertheless sutures represent the significantly stronger and cheaper fixation method.

Fractures around the hip: inducing life-like fractures as a basis for enhanced surgical training

INTRODUCTION

In this study we investigated if realistic fracture patterns around the hip can be produced on human cadaveric specimens with intact soft tissue envelope. Possible applications of such fractured specimens would be in surgical training.

MATERIALS AND METHODS

7 cadaveric specimens (2 male, 5 female, 2 formalin-fixed, 5 fresh-frozen) were fractured. 2 specimens were fractured on both femurs, 5 only on one side, resulting in 9 fractures total. 5 fractures were set in our custom-made drop-test bench, 2 fractures by inducing axial force using a hammer, and the remaining 2 fractures by a direct dorsal approach and a chisel. AO/OTA and Pauwels classification were used to classify the fractures on the specimens by two independent trauma surgeons.

RESULTS

In our drop-test bench, axial load with the femur adducted by 10° resulted in an intertrochanteric fracture (AO type A1.3), adducted by 20° resulted in a femoral neck fracture (Pauwels type III). Fracture induction using a hammer resulted in two intertrochanteric fractures (AO type A2.2 right, A3.3 left). The use of a chisel resulted in both cases in a femoral neck fracture. The acetabulum could be fractured multifragmentarily through use of a hemiprosthesis as a stamp.

CONCLUSION

A high energetic impulse induced by a custom-made drop-test bench can successfully simulate realistic proximal femur and acetabular fractures in cadaveric specimens with intact soft tissue. Furthermore, axial load using a hammer as well as using a chisel through a direct dorsal approach represent additional methods for fracture induction. These pre-fractured specimens can be utilized in surgical education to provide a realistic teaching experience for specialized trauma education courses.

A "Comma Sign"-Directed Subscapularis Repair in Anterosuperior Rotator Cuff Tears Yields Biomechanical Advantages in a Cadaveric Model

BACKGROUND

Additional stabilization of the "comma sign" in anterosuperior rotator cuff repair has been proposed to provide biomechanical benefits regarding stability of the repair.

PURPOSE

This in vitro investigation aimed to investigate the influence of a comma sign-directed reconstruction technique for anterosuperior rotator cuff tears on the primary stability of the subscapularis tendon repair.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 18 fresh-frozen cadaveric shoulders were used in this study. Anterosuperior rotator cuff tears (complete full-thickness tear of the supraspinatus and subscapularis tendons) were created, and supraspinatus repair was performed with a standard suture bridge technique. The subscapularis was repaired with either a (1) single-row or (2) comma sign technique. A high-resolution 3D camera system was used to analyze 3-mm and 5-mm gap formation at the subscapularis tendon-bone interface upon incremental cyclic loading. Moreover, the ultimate failure load of the repair was recorded. A Mann-Whitney test was used to assess significant differences between the 2 groups.

RESULTS

The comma sign repair withstood significantly more loading cycles than the single-row repair until 3-mm and 5-mm gap formation occurred (P≤ .047). The ultimate failure load did not reveal any significant differences when the 2 techniques were compared (P = .596).

CONCLUSION

The results of this study show that additional stabilization of the comma sign enhanced the primary stability of subscapularis tendon repair in anterosuperior rotator cuff tears. Although this stabilization did not seem to influence the ultimate failure load, it effectively decreased the micromotion at the tendon-bone interface during cyclic loading.

CLINICAL RELEVANCE

The proposed technique for stabilization of the comma sign has shown superior biomechanical properties in comparison with a single-row repair and might thus improve tendon healing. Further clinical research will be necessary to determine its influence on the functional outcome.

Primary stability of fixation methods for periprosthetic fractures of the humerus: a biomechanical investigation

BACKGROUND

The incidence of periprosthetic fractures of the proximal humerus is gradually increasing, following an increase in reverse shoulder arthroplasties in recent years. Locking plate fixation and revision arthroplasty are both valuable treatment methods. However, the primary stability of fixation methods for periprosthetic fractures has not been investigated in detail. The aim of this study was to analyze and compare the primary stability of the common treatment measures.

MATERIALS AND METHODS

Cemented reverse total shoulder arthroplasty (Delta Xtend; DePuy Synthes, Warsaw, IN, USA) was performed in 5 shoulders, and a distal, mid-diaphysis humeral fracture (Wright and Cofield type B) was induced. The implant was left in place, and 3 distinct fixation scenarios were tested: osteosynthesis using 4.5-mm locking plate fixation (subgroup A), 4.5-mm locking plate fixation with an additional 3.5-mm locking plate (subgroup B), and 4.5-mm locking plate fixation with an additional K-wire cerclage (subgroup C). The specimens were tested in a biomechanical setup simulating activities of daily living including rotation. Strain gauges (4-wire strain at 120 Ω; Vishay Measurements Group, Chartres, France) mounted on the 4.5-mm locking plates were used to evaluate the strain of the fixation and to give an estimate of primary stability.

RESULTS

Regarding the simulation of activities of daily living, no statistically significant differences were found in the measured strains on the locking plate between subgroups A, B, and C. A maximum measured strain of 216.85 μm/m in subgroup A resulted in bending of the locking plate (length, 134 mm) of 0.03 mm. In subgroup B (277.01 μm/m), the plate strained 0.04 mm compared with a strain measurement of 0.01 mm in subgroup C (75.93 μm/m).

CONCLUSION

Additional K-wire cerclages or additional 3.5-mm locked plating did not increase primary stability. With a stable prosthetic implant in place, 4.5-mm locked plating is sufficient to address periprosthetic humeral shaft fractures in the present in vitro setup.

What to expect? Injury patterns of Electric-Scooter accidents over a period of one year - A prospective monocentric study at a Level 1 Trauma Center

Purpose

E-scooters are a new type of urban transportation utilized in Germany since June 2019, primarily in larger cities in the context of sharing offers. Such electrically operated standing scooters can be driven at a maximum speed of 20 km/h. A helmet is not mandatory. The aim of this prospective study is to document the injury patterns over the period of 1 year and compare our findings with already available data.

Methods

Over a period of 1 year (July 2019–July 2020), data on E-scooter-related accidents treated at a level 1 trauma center of a major German city were prospectively documented. Injury patterns were analyzed, and epidemiological data evaluated.

Results

Fifty-nine (35 female, 24 male) accidents were included in the observation period. Mean age of accident victims was 30.03 years (± 9.32). Alcohol influence at the time of accident was detected in 9 cases (15.25%). Many of the accident victims suffered multiple injuries. Most of the injuries were upper (50.84%) and lower extremity (47.45%) as well as craniofacial injuries (62.71%). A helmet was not worn in any of the cases.

Conclusion

In the year following their introduction, E-scooter-related accidents have led to an additional burden on the emergency capacities of the involved University Hospital, especially in the summer months of 2019. Protective equipment is de facto not worn. Injuries to the extremities, head, and face were most common. None of the accident victims died. This coincides with results from other major cities in national and international comparison. A more intensive education about injury consequences of unprotected E-scooter use and the discussion of a possible obligation to wear a helmet and further protection equipment for the extremities should take place.

Intratendinous Strain Variations of the Supraspinatus Tendon Depending on Repair Technique: A Biomechanical Analysis Regarding the Cause of Medial Cuff Failure

BACKGROUND

Double-row (DR) and transosseous-equivalent (TOE) techniques for rotator cuff repair offer more stability and promote better tendon healing compared with single-row (SR) repairs and are preferred by many surgeons. However, they can lead to more disastrous retear patterns with failure at the medial anchor row or the musculotendinous junction. The biomechanics of medial cuff failure have not been thoroughly investigated thus far.

PURPOSE

To investigate the intratendinous strain distribution within the supraspinatus tendon depending on repair technique.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve fresh-frozen cadaveric shoulders were used. The intratendinous strain within the supraspinatus tendon was analyzed in 2 regions-(1) at the footprint at the greater tuberosity and (2) medial to the footprint up to the musculotendinous junction-using a high-resolution 3-dimensional camera system. Testing was performed at submaximal loads of 40 N, 60 N, and 80 N for intact tendons, after SR repair, after DR repair, and after TOE repair.

RESULTS

The tendon strain of the SR group differed significantly in both regions from that of the intact tendons and the TOE group at 40 N (P≤ .043) and from the intact tendons, the DR group, and the TOE group at 60 N and 80 N (P≤ .048). SR repairs showed more tendon elongation at the footprint and less elongation medial to the footprint. DR and TOE repairs did not provide significant differences in tendon strain when compared with the intact tendons. However, the increase in tendon strain medial to the footprint from 40 N to 80 N was significantly more pronounced in the DR and TOE group (P≤ .029).

CONCLUSION

While DR and TOE repair techniques more closely reproduced the strains of the supraspinatus tendon than did SR repair in a cadaveric model, they showed a significantly increased tendon strain at the musculotendinous junction with higher loads in comparison with the intact tendon.

CLINICAL RELEVANCE

DR and TOE rotator cuff reconstructions lead to a more anatomic tendon repair. However, their use has to be carefully evaluated whenever tendon quality is diminished, as they lead to a more drastic increase in tendon strain medial to the footprint, putting these repairs at risk of medial cuff failure.

Coronoid process reconstruction with a distal clavicle autograft: an in silico analysis of fitting accuracy

BACKGROUND

The coronoid process plays a vital role in preserving elbow stability. In cases of acute or chronic deficiency of the coronoid process, reconstruction is warranted to restore stability and to avoid early joint degeneration. The distal clavicle might be a useful osteochondral autograft for coronoid reconstruction with low donor-site morbidity. This study evaluated the fitting accuracy of the distal clavicle as an autograft for coronoid process reconstruction.

METHODS

One hundred upper-extremity computed tomography scans of 85 body donors were available for this study (mean age, 69 ± 17 years; 46 male and 39 female donors; 15 bilateral specimens). Standardized 40% transverse defects of the coronoid process were digitally created; the distal clavicles were digitally harvested and placed onto the defects by a best-fit technique in 2 different orientations using commercially available software: (1) with the superior aspect of the articular surface of the graft oriented toward the coronoid tip and (2) with the inferior aspect of the articular surface of the graft oriented toward the coronoid tip. The fitting accuracy of the grafts to the native coronoid process was evaluated from lateral to medial using custom code.

RESULTS

Regardless of the orientation of the graft, the distal clavicle provided a good fit in the central portion of the coronoid process. In the lateral and medial aspects of the defect, however, the fitting accuracy of the graft declined significantly (P ≤ .044). No significant differences were observed between ipsilateral and contralateral grafts (P ≥ .199). The intrarater reliability was excellent.

CONCLUSION

The results of this study suggest that a distal clavicle autograft may be suitable to replace a transverse defect of the coronoid process; however, it may not fully reconstruct the anteromedial and anterolateral aspects of the coronoid.

Inducing pilon fractures in human cadaveric specimens depending on the injury mechanism: a fracture simulation

BACKGROUND

Operative management of pilon fractures, especially high-energy compression injuries, is a challenge. Operative education is of vital importance to handle these entities. Not rarely, it is cut by economics and staff shortage. As public awareness toward operative competence rises, surgical cadaver courses that provide pre-fractured specimens can improve realism of teaching scenarios. The aim of this study is to introduce a realistic pilon fracture simulation setup regarding the injury mechanism.

MATERIALS AND METHODS

8 cadaveric specimens (two left, six right) were fixed onto a custom drop-test bench in dorsiflexion (20°) and light supination (10°). The proximal part of the lower leg was potted, and the specimen was exposed to a high energetic impulse via an axial impactor. CT imaging was performed after fracture simulation to detect the exact fracture patterns and to classify the achieved fractures by two independent trauma surgeons. (AO/OTA recommendations and the Rüedi/Allgöwer).

RESULTS

All cadaveric specimens could be successfully fractured: 6 (75%) were identified as a 43-C fracture and 2 (25%) as 43-B fracture type. Regardless of the identical mechanism two different kinds of fracture types were reported. In five cases (62.5%), the fibula was also fractured and in three specimens, a talus fracture was described. There was no statistically significant correlation found regarding Hounsfield Units (HU) and age as well as HU and required kinetic energy.

CONCLUSION

A high energetic axial impulse on a fixed ankle specimen in light dorsiflexion (20°) and supination (10°) induced by a custom-made drop-test bench can successfully simulate realistic pilon fractures in cadaveric specimens with intact soft tissue envelope. Although six out of eight fractures (75%) were classified as a 43-C fracture and despite putting a lot of effort into the mechanical setup, we could not achieve an absolute level of precision. Therefore, we suggest that the injury mechanism is most likely a combination of axial loading, shear and rotation.

LEVEL OF EVIDENCE

III.

The effect of glenoid lateralization and glenosphere size in reverse shoulder arthroplasty on deltoid load: A biomechanical cadaveric study

Purpose

Use of a relatively larger glenosphere with some larger overhang helps to minimize posterior impingement and some degree of glenoid lateralization is also beneficial in reverse shoulder arthroplasty (RSA). The optimal amounts of inferior overhang and lateralization are not agreed upon. The purpose of this in-vitro biomechanical study is to analyze the effect of glenosphere size and glenoid lateralization on deltoid load, focusing on differences in its three distinct heads.

Methods

Reverse shoulder arthroplasty (DeltaXtend, Fa. Depuy/Synthes) was performed on six cadaveric specimens. The load on each head of the deltoid muscle (spinalis, acromialis, and clavicularis) was measured indirectly by transferring deformation (μm/m) via strain gauges (Fa. Vishay) with stepwise lateralization: +0 mm (subgroup I), +5 mm (subgroup II), +10 mm (subgroup III). Each scenario was done with a 38 mm (group A) and a 42 mm (group B) glenosphere.

Results

In group A as well in group B, the mean measured deformation in the respective titanium omega increased with lateralization in the clavicular (AI: 119.6 μm/m, AIII: 307.3 μm/m; BI: 173.3 μm/m, BIII: 358.5 μm/m), in the spinal (AI: 85.3 μm/m, AIII: 188.5 μm/m; BI: 138.8 μm/m, BIII 261.2 μm/m) and in the acromial head (AI: 340.5 μm/μ; AIII: 454.2 μm/m; BI: 388.5 μm/m, BIII: 538.8 μm/m). A significant difference between the subgroups in the spinal (p = .048) and clavicular heads (p = .028) was found. The use of a 42 mm glenosphere increased significantly the load in each segment.

Conclusion

Lateralization and glenosphere size increased significantly deltoid muscle loading, especially in the clavicular head. According to these in-vitro data, the high variability in the amount of lateralization influences the soft-tissue balance in reverse shoulder arthroplasty.

Level of evidence

Basic science study.

The treatment of anteromedial coronoid facet fractures: a systematic review

BACKGROUND

Fractures of the anteromedial facet (AMF) of the coronoid process are caused by a varus posteromedial rotational injury force, leading to instability in the ulnohumeral joint. AMF fractures are usually accompanied by avulsion of the lateral ulnar collateral ligament (LUCL). O'Driscoll's description and classification of AMF coronoid fractures has increased awareness and interest in this injury, but the optimal treatment has yet to be decided.

METHODS

We systematically reviewed the available literature searching electronic databases, MEDLINE using the PubMed interface and Embase. The primary objective was to determine outcome scores but also complication and revision rates depending on the fracture and its therapy in order to gain a more comprehensive picture. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were applied.

RESULTS

Initially, 304 publications were identified. Finally, 10 studies were left for inclusion, all of them retrospective in design, comprising 128 patients; the majority of them were male (75.7%). A total of 114 patients (89.1%) were treated surgically and 14 patients (10.9%) were treated conservatively. Among the surgically treated patients, 70.2% were treated with LUCL refixation. The average Mayo Elbow Performance Score of the surgically treated patients was 91.5 points. The average Mayo Elbow Performance Score of the conservatively treated patients was 91.4 points. A total of 10 patients (7.8%) required reoperation.

CONCLUSION

Surgery of AMF fractures leads to a satisfactory functional outcome in the vast majority of patients independent of the subtype. An algorithm for LUCL fixation is still pending. Conservative treatment may be considered under strict preconditions, especially for nondisplaced subtype 1 and 2 fractures, as these fractures show satisfactory functional outcomes when treated nonoperatively.

The treatment of isolated Mason type II radial head fractures: a systematic review

BACKGROUND

Fractures of the radial head represent the most common bony injury of the elbow in adults. Radial head fractures are classified according to Mason or one of its classification modifications. Current literature does not indicate consensus on whether to treat isolated stable type II radial head fracture patterns with open reduction and internal fixation (ORIF) or nonoperatively, especially, when there is no mechanical block to motion.

METHODS

We systematically reviewed the available literature searching electronic databases, that is, MEDLINE using the PubMed interface and Embase, for studies published between 2011 and 2020. The primary objective was to contrast the outcome scores of these 2 different study groups and the pitfalls accompanied with the 2 different approaches. The PRISMA guidelines were applied.

RESULTS

The literature search left 11 studies for inclusion, all but 1 retrospective in design, comprising 319 patients. A total of 218 patients (68.3%) were treated with ORIF and 101 patients (31.7%) were treated nonoperatively. Our findings indicate that ORIF does not provide better results when compared to nonoperatively treated patients concerning functional outcome parameters. Treatment success, defined as excellent or good results according to the Mayo Elbow Performance Score or the Broberg and Morrey score, among the patients treated with ORIF was 90.9%; 7.1% were in need of subsequent surgery and 5.2% had radiologic osteoarthritic changes of the radial column. In addition, 95.1% of the nonoperative cohort were treated successfully, and osteoarthritis was present in 11.9%. Mean follow-up period of the ORIF and the nonoperative cohort was 73 and 39 months, respectively.

CONCLUSION

ORIF and nonoperative treatment of isolated Mason type II radial head fractures provide comparably satisfactory functional outcomes, without significant differences. Consideration of age, activity level and potential risks is recommended before making any treatment decision. Subsequent surgery rates were higher for patients treated with ORIF than for those treated nonoperatively and should be discussed. However, development of osteoarthritis of the radial column appears to be more likely after nonoperative treatment. The study pool remains limited, and implications of this review should be handled with caution.

The effect of metaglene lateralization on joint mobility of reverse shoulder arthroplasty: A cadaveric biomechanical study

Introduction

Lateralization of the metaglene reduces scapular notching or impingement. However, the effect on joint mobility remains unclear. With increased attention to reverse shoulder arthroplasty over the past years, the aim of this biomechanical study is to analyze the effect of metaglene lateralization on range of motion in reverse shoulder arthroplasty.

Methods

Reverse shoulder arthroplasty (DeltaXtend; Fa. Depuy/Synthes) was performed in 7 cadaveric shoulders. Lateralization of the metaglene was performed in increments, using spacers of +0 mm (subgroup I), +5 mm (subgroup II), +10 mm (subgroup III). Deltoid muscle (pars clavicularis, acromialis and spinalis), teres minor (TMI), infraspinatus (IF) and subscapularis muslces (SSC) were loaded separately. Range of motion was measured by using a motion capture system (Optotrak Certus) in the sagittal plane (z-axis), coronar plane (x-axis) and transversal plane (y-axis). A custom-made biomechanical test set up was used to test the samples with a constant preload with additional testing load up to 4 kg on each muscle.

Results

Specimens showed a tendency towards increased range of motion in abduction (deltoid, pars acromialis), external rotation (IS/TMI) and internal rotation (SSC) in subgroup II, compared to subgroups I and III, without reaching the level of significance Abduction at maximum used load was 46° (subgroup I), 62° (subgroup II) and 22° (subgroup III). The mean external rotation (ISF) at maximum used load was 25° (I), 28° (II) and 24° (III). Mean internal rotation was 22° (subgroup I), 48° (subgroup II) and 26° (subgroup III).

Conclusion

Moderate lateralization of the glenosphere of +5 mm has improved the range of motion in our experimental cadaveric setup. Especially a higher internal and external rotation can be reached with less load.Level of evidence III.

[Radial head fractures : Epidemiology, diagnosis, treatment and outcome]

Radial head fractures account for the majority of bony injuries to the elbow. The usual clinical signs include hemarthrosis, pain and limitations in movement. The standard diagnostic tool is radiological imaging using X‑rays and for more complex fractures, computed tomography (CT). Concomitant ligamentous injuries occur more frequently than expected and must be reliably excluded. The classification is based on the modified Mason classification. Mason type I fractures are usually treated conservatively with immobilization and early functional aftercare. Mason type II fractures can be well-addressed by screw osteosynthesis but higher grade fractures (Mason types III-IV) can necessitate a prosthetic radial head replacement. In this case, prosthesis implantation is to be preferred to a radial head resection. The outcome after treatment of radial head fractures can be described as good to very good if all accompanying injuries are adequately addressed.

Radial head fractures with interposed capitellar cartilage fragment-hindrance to bone healing-a case series

INTRODUCTION

Radial head fractures account for the majority of bony elbow injuries. The individual treatment options have been described in detail. In some cases, however, an unusual concomitant injury occurs, which can significantly impede primary osteosynthesis and healing. This concomitant injury can be an interposing cartilaginous capitellar fragment.

METHODS

This retrospective study describes four cases of trapped cartilage fragments of the capitellum that compromised primary osteosynthesis or primary conservative healing of a radial head fracture. Radiological imaging, function and pain level are presented pre- and postoperatively (mean follow-up 9.25 months).

RESULTS

None of the four cases showed preoperative evidence of an incarcerated cartilage fragment of the capitellum. They all showed limited elbow range of motion. CT examinations were performed in all cases. In each case, the cartilage fragment was first sighted upon surgery, subsequently removed and the fractures treated with ORIF. Mean follow-up was of 9.25 months. All fractures healed, with excellent function and low pain scores.

CONCLUSIONS

This study presents rare cases of a trapped humeral cartilage fragment in radial head fractures. Radiological imaging including CT scans cannot reliably detect this concomitant injury. Therefore, this problem becomes apparent and treatable only during surgery. A high degree of suspicion is necessary especially in patients with minimally displaced fractures associated with limited elbow motion and a gap at the fracture site as treating these injuries conservatively may lead to poor outcome.

Overlengthening of the radial column in radial head replacement: a review of the literature and presentation of a classification system

BACKGROUND

Radial head arthroplasty is a common procedure in elbow surgery. It has been shown to be of benefit for the patients, but there also are relevant complications that should be prevented if possible. One significant complication is overlengthening of the radial head prosthesis. In overlengthening, the head of the prosthesis overextends the physiological level of the native radial head and leads to overcompression in the radiohumeral joint. Rapid erosion and arthritic changes may then impede the clinical outcome. The incidence of overlengthening is not precisely known, but estimations range to up to 20% of all implanted prostheses.

METHODS

The present review discusses the available body of literature on overlengthening and lines out a classification system that may be used to guide treatment algorithms. The classification is based on the personal experiences of the author during their clinical practice.

RESULTS

In low-grade overlengthening (type I) conservative treatment can be an option. In Types II-IV usually revision surgery is needed. Depending on the state of the capitulum and joint stability, it is possible re-implant a prosthesis, or rely on implant removal alone.

DISCUSSION

The present review aimed at shedding light into overlengthening as a complication radial head replacement and to help identify and treat it.

Neuromuscular Electrical Stimulation Reduces Leg Cramps in Patients With Lumbar Degenerative Disorders: A Randomized Placebo-Controlled Trial

Objectives

Lumbar spinal stenosis (LSS) and lumbar disc herniation (LDH) are often accompanied by frequently occurring leg cramps severely affecting patients' life and sleep quality. Recent evidence suggests that neuromuscular electric stimulation (NMES) of cramp‐prone muscles may prevent cramps in lumbar disorders.

Materials and Methods

Thirty‐two men and women (63 ± 9 years) with LSS and/or LDH suffering from cramps were randomly allocated to four different groups. Unilateral stimulation of the gastrocnemius was applied twice a week over four weeks (3 × 6 × 5 sec stimulation trains at 30 Hz above the individual cramp threshold frequency [CTF]). Three groups received either 85%, 55%, or 25% of their maximum tolerated stimulation intensity, whereas one group only received pseudo‐stimulation.

Results

The number of reported leg cramps decreased in the 25% (25 ± 14 to 7 ± 4; p = 0.002), 55% (24 ± 10 to 10 ± 11; p = 0.014) and 85%NMES (23 ± 17 to 1 ± 1; p < 0.001) group, whereas it remained unchanged after pseudo‐stimulation (20 ± 32 to 19 ± 33; p > 0.999). In the 25% and 85%NMES group, this improvement was accompanied by an increased CTF (p < 0.001).

Conclusion

Regularly applied NMES of the calf muscles reduces leg cramps in patients with LSS/LDH even at low stimulation intensity.

Injuries to the Coronoid Process of the Ulna with Involvement of the Lesser Sigmoid Notch

INTRODUCTION

This study aimed to describe the involvement of the lesser sigmoid notch in fractures to the coronoid process. We hypothesized that injuries to the lateral aspect of the coronoid process regularly involve the annular ligament insertion at the anterior lesser sigmoid notch.

MATERIAL AND METHODS

Patients treated for a coronoid process fracture at our institution between 06/2011 and 07/2018 were included. We excluded patients < 18 years, patients with arthritic changes or previous operative treatment to the elbow, and patients with concomitant injuries to the proximal ulna. In patients with involvement of the lesser sigmoid notch, the coronoid height and fragment size (anteroposterior, mediolateral, and craniocaudal) were measured.

RESULTS

Seventy-two patients (mean age: 47 years ± 17.6) could be included in the study. Twenty-one patients (29.2%) had a fracture involving the lateral sigmoid notch. The mean anteroposterior fragment length was 7 ± 1.6 mm. The fragment affected a mean of 43 ± 10.8% of the coronoid height. The mean mediolateral size of the fragment was 10 ± 5.0 mm, and the mean cranio-caudal size was 7 ± 2.7 mm.

CONCLUSION

Coronoid fractures regularly include the lesser sigmoid notch. These injuries possibly affect the anterior annular ligament insertion which is important for the stability of the proximal radioulnar joint and varus stability of the elbow.

Osteosynthesis of Phalangeal Fractures: Biomechanical Comparison of Kirschner Wires, Plates, and Compression Screws

PURPOSE

The aim of this study was to compare several osteosynthesis techniques (intramedullary headless compression screws, T-plates, and Kirschner wires) for distal epiphyseal fractures of proximal phalanges in a human cadaveric model.

METHODS

A total of 90 proximal phalanges from 30 specimens (index, ring, and middle fingers) were used for this study. After stripping off all soft tissue, a transverse distal epiphyseal fracture was simulated at the proximal phalanx. The 30 specimens were randomly assigned to 1 fixation technique (30 per technique), either a 3.0-mm intramedullary headless compression screw, locking plate fixation with a 2.0-mm T-plate, or 2 oblique 1.0-mm Kirschner wires. Displacement analysis (bending, distraction, and torsion) was performed using optical tracking of an applied random speckle pattern after osteosynthesis. Biomechanical testing was performed with increasing cyclic loading and with cyclic load to failure using a biaxial torsion-tension testing machine.

RESULTS

Cannulated intramedullary compression screws showed significantly less displacement at the fracture site in torsional testing. Furthermore, screws were significantly more stable in bending testing. Kirschner wires were significantly less stable than plating or screw fixation in any cyclic load to failure test setup.

CONCLUSIONS

Intramedullary compression screws are a highly stable alternative in the treatment of transverse distal epiphyseal phalangeal fractures. Kirschner wires seem to be inferior regarding displacement properties and primary stability.

CLINICAL RELEVANCE

Fracture fixation of phalangeal fractures using plate osteosynthesis may have the advantage of a very rigid reduction, but disadvantages such as stiffness owing to the more invasive surgical approach and soft tissue irritation should be taken into account. Headless compression screws represent a minimally invasive choice for fixation with good biomechanical properties.