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.

[Minimally invasive procedures in the early stages of trapeziometacarpal joint osteoarthritis : Denervation, arthroscopy and autologous fat transplantation]. / Minimal-invasive Verfahren im Frühstadium der Daumensattelgelenksarthrose : Denervierung, Arthroskopie, autologe Fetttransplantation.

BACKGROUND: Resection arthroplasty of the trapezium with or without tendon interposition is the standard procedure in the treatment of advanced, symptomatic thumb carpometacarpal joint osteoarthritis. Treatment recommendation in the early stages without visible or minimal radiographic changes is often difficult, especially when conservative treatment methods have already been exhausted. In these cases, there is the possibility of the minimally invasive methods of denervation, arthroscopic procedures and autologous fat transplantation. OBJECTIVES: Which minimally invasive procedures are available for the treatment of thumb carpometacarpal joint osteoarthritis and how is their value to be assessed? METHODS: The minimally invasive methods of denervation, arthroscopic procedures and autologous fat transplantation for the treatment of thumb carpometacarpal joint osteoarthritis are described and current results from the literature are discussed. RESULTS: Good results have been reported with all three procedures. However, the reports are almost exclusively based on retrospective studies with small numbers of patients, which lack control groups, so the results cannot be regarded as definitive. CONCLUSIONS: Denervation, arthroscopic procedures and autologous fat transplantation appear to be suitable methods in the early stages of thumb carpometacarpal joint osteoarthritis. Further studies, especially comparative randomised trials that report medium and long-term results, would allow further assessment of these methods.

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.

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.

Long-term outcome after arthroscopic debridement of Palmer type 2C central degenerative lesions of the triangular fibrocartilage complex.

PURPOSE: The purpose of this study was to report long-term objective and patient-reported outcome after arthroscopic debridement of central degenerative triangular fibrocartilage complex (TFCC) lesions. METHODS: A total of 17 patients with central degenerative TFCC (Palmer type 2C) lesions and ulnar positive variance who were treated by arthroscopic debridement were retrospectively reviewed. Mean follow-up was 8.8 years. Assessment facilitating the Modified Mayo Wrist score (MMWS), the Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH score), recording of pain level and of patient satisfaction, and radiological examination were done. RESULTS: Patients reached a pain level of 1.7 VAS, MMW score of 92, and DASH score of 22. No significant differences could be detected between the operated and the contralateral extremity regarding range of motion and grip strength for all patients. No perioperative complications occurred. CONCLUSION: Arthroscopic debridement of central degenerative TFCC lesions is safe, reliable, and efficacious even for ulnar positive variance. LEVEL OF EVIDENCE: Therapeutic IV.

Viscoelastic properties of the human A2 finger pulley.

INTRODUCTION: Biomechanical evaluation of the viscoelastic properties tissue deformation, stiffness, and maximum breaking load of the human A2 pulley. We hypothesized that the A2 pulleys of index, middle, and ring fingers exhibit no difference regarding the aforementioned biomechanical parameters. METHODS: Forty-one A2 pulleys of 14 upper extremities (8 body donors) were assessed. Cyclic and load-to-failure testing were performed. The biomechanical parameters tissue deformation during cyclic and load-to-failure testing, stiffness, and maximum breaking load were determined. RESULTS: No significant differences between the fingers could be detected regarding the biomechanical parameters. A significant negative correlation could be detected between stiffness and deformation of the pulley. Significant positive correlations could be identified between stiffness and maximum breaking load and between maximum breaking load and deformation of the pulleys. CONCLUSIONS: Assessment of the viscoelastic properties of the A2 finger pulley promotes precise diagnosis of pulley lesions and will help to optimize treatment.

[Radial head fractures : Epidemiology, diagnosis, treatment and outcome]. / Radiuskopffrakturen : Epidemiologie, Diagnose, Behandlung und 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 X­rays 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.

[Tenolysis of extensor and flexor tendons of the hand]. / Tenolyse von Streck- und Beugesehnen an der Hand.

BACKGROUND: Unrestricted gliding of extensor and flexor tendons is essential for normal functioning of the hand. If tendon gliding is impaired, a restricted range of motion of finger joints and, finally, joint stiffness result. OBJECTIVES: To answer the questions about the causes of tenodesis in the hand, which examinations are most informative, how tenolysis is technically performed, and what results can be expected. METHODS: The reasons, examinations, surgical technique, and results of extensor and flexor tendon tenolysis are presented. RESULTS: Based on the data in the literature tenolysis of flexor tendons leads to range of motion that is only 50-60% of the preoperative range of motion. In about 20% of patients, deterioration as serious as secondary tendon rupture is observed. Meaningful results of extensor tendon tenolysis have not yet been published. CONCLUSIONS: Tenolysis of extensor and flexor tendons in the hand is a demanding surgical procedure, and in addition to detailed knowledge of anatomy and biomechanics, it requires sufficient experience-especially following the primary repair of tendon injuries. The earliest indication for tenolysis can occur at about 3 months, usually after 6 months, if continuous intensive hand therapy and splinting have not been successful. General and individual benefits and risks must be carefully weighed. The key to successful tenolysis is the patient's access to and unrestricted participation in competent postoperative treatment, ideally performed by a specialist in hand therapy, which may last for weeks or months.

[Revision surgery after failed (partial-) arthrodesis of the wrist]. / Revisionen nach fehlgeschlagenen (Teil­)Versteifungen am Handgelenk.

(Partial) arthrodeses of the wrist have been proven cornerstones to treat many lesions for decades, especially in the case of revision surgery. Four-corner, scapho-trapezo-trapezoidal (STT), radio-scapho-lunate (RSL) and total wrist fusions are very common techniques in hand surgery. However, even these proven surgical procedures have significant non-fusion rates. Prior to revising a failed arthrodesis, it is essential to analyse the latter failure precisely. A technically adequate revision is only feasible when based on a correct and meticulous analysis. The understanding of the biological processes and technical aspects of the implants are the basis for solving this issue.

Peroneal nerve location at the fibular head: an anatomic study using 3D imaging.

INTRODUCTION: Injuries to the peroneal nerve are a common complication in operative treatment of proximal tibial or fibular fractures. To minimize the risk of iatrogenic injury to the nerve, detailed knowledge of the anatomy of the peroneal nerve is essential. Aim of this study was to present a detailed description of the position and branching of the peroneal nerve based on 3D-images to assist preparation for surgical approaches to the fibular head and the tibial plateau. METHODS: The common peroneal nerve, the deep and the superficial peroneal nerve were marked with a radiopaque thread in 18 formalin-embalmed specimens. Three-dimensional X-ray scans were then acquired from the knee and the proximal lower leg in full extension of the knee. In 3D-reconstructions of these scans, distances of the common peroneal nerve and its branches to clearly defined osseous landmarks were measured digitally. Furthermore, the height of the branching of the common peroneal nerve was measured in relation to the landmarks. RESULTS: The mean distance of the common peroneal nerve at the level of the tibial plateau to its posterior osseous limitation was 7.92 ± 2.42 mm, and 1.31 ± 2.63 mm to the lateral osseous limitation of the tibia. In a transversal plane, distance of the common peroneal nerve branching was 27.56 ± 3.98 mm relative to the level of the most proximal osseous extension of fibula and 11.77 ± 6.1 mm relative to the proximal extension of the tibial tuberosity. The deep peroneal nerve crossed the midline of the fibular shaft at a distance of 22.14 mm ± 4.35 distally to the most proximal extension of the fibula, the superficial peroneal nerve at a distance of 33.56 mm ± 6.68. CONCLUSION: As the course of the peroneal nerve is highly variable in between individuals, surgical dissection for operative treatment of proximal posterolateral tibial or fibular fractures has to be done carefully. We defined an area were the peroneal nerve and its branches are unlikely to be found. However, specific safe zones should not be utilized due to the individual anatomic variation.

[Anatomy of the metacarpophalangeal and proximal interphalangeal finger joint with respect to arthroplasty]. / Anatomie des Fingergrund- und -mittelgelenks unter Berücksichtigung der Endoprothetik.

BACKGROUND: Precise knowledge of the anatomy and biomechanics of the metacarpophalangeal and proximal interphalangeal joint is the basis for both indication and implantation of a finger joint prosthesis. Currently available finger joint prostheses inadequately take into account individual, ethnological, gender, age, and side differences. They can remain compromised despite the possible combination of their components. OBJECTIVES: To elucidate which problems of finger joint arthroplasty exist due to the anatomy and biomechanics of the metacarpophalangeal and proximal interphalangeal joints. METHODS: The anatomy and biomechanics of the metacarpophalangeal and proximal interphalangeal joint are described, and the problems and solutions of finger joint arthroplasty are presented. RESULTS: Despite precise knowledge of the anatomy and biomechanics of the metacarpophalangeal and proximal interphalangeal joint, not all problems of finger joint arthroplasty have been solved. However, a modular surface replacement appears promising for the proximal interphalangeal joint. CONCLUSIONS: Artificial joint replacement of the metacarpophalangeal and proximal interphalangeal joint is difficult with regard to morphology, small bone dimensions, complex biomechanics, and the strain of the hand. Further improvements, especially in design, should be achieved by exact anatomical imitation.

[Anatomy of the trapeziometacarpal joint in the context of arthroplasty]. / Anatomie des Daumensattelgelenks unter Berücksichtigung der Endoprothetik.

The thumb has a crucial role in the hand due to its position with regard to the fingers. The CMC-1 joint enables an extraordinary range of motion, since its geometry allows for opposition. The former joint may often succumb to osteoarthritis because a great range of motion in combination with large forces, small contact areas, and thorough usage are always present. Joint replacement is challenged by the great range of motion based on the necessary joint stability and the demand for sufficient pain reduction. This review highlights the anatomy of the CMC-1 joint with regard to joint preplacement solutions.

[Metacarpophalangeal joint replacement]. / Der Gelenkersatz der Fingergrundgelenke.

BACKGROUND: Arthroplasty of metacarpophalangeal (MCP) joints is crucial for patients with rheumatoid arthritis. Motion preserving therapies are mandatory for this joint, since loss of function of the MCP joint is detrimental. Many protheses or spacers have been introduced over the last 80 years, but most of them have been dismissed due to major complications. CURRENT PROCEDURES: Since the 1960s the Swanson spacer has been established as the reference standard for motion preserving procedures of the finger MCP joints. High fracture rates of the spacer do not seem to limit function and patient satisfaction after all. Current long-term studies show at least promising results for pyrolytic carbon protheses with respect to range of motion, survival, and revision rates in comparison to the Swanson spacer.

Reconstruction of complex radial head fractures using fine-threaded K-wires : clinical outcome and remaining instability.

Radial head replacement or ORIF are established treatment options for Mason type-III and type-IV fractures. The aim of this study was to provide results for reconstruction of these complex fractures using fine-threaded K-wires. We present results after reconstruction of 15 Mason type-III and 8 Mason type-IV fractures. Parameters used to describe the functional outcome were pain level, range of motion, and clinical scores. To estimate the elbow stability we performed ultrasound examinations under valgus/varus stress. All radial heads could be reconstructed. The average resting pain level was 0.9 of 10. The average ROM for extension/flexion was 134°, average forearm rotation was 159°. For the whole patient collective the mean MEPS was 86.5 points and the mean QuickDASH was 16.8 points with no significant difference for both groups. We can recommend ORIF with fine-threaded K-wires for Mason type-III and type-IV fractures of the radial head. Ligamentous injuries can be addressed successfully with external fixation.

Pronator quadratus repair with a part of the brachioradialis muscle insertion in volar plate fixation of distal radius fractures: a prospective randomised trial.

INTRODUCTION: Stable pronator quadratus repair following volar plate fixation of distal radius fractures with complete plate coverage is difficult. MATERIALS AND METHODS: This study compares a modified pronator quadratus repair technique involving the brachioradialis muscle insertion (test group) with a conventional radial incision through the muscle without pronator quadratus repair (standard group). This prospective randomised study included 16 patients in the test group and 12 in the standard group; all were available for clinical, radiographic and ultrasound examination at a mean follow-up of 15 months. RESULTS: Pronator quadratus repair was feasible in all test group patients, and complete coverage of the distal plate was achieved in 11. No differences in functional outcome were observed between the groups. CONCLUSION: Pronator quadratus repair with a part of the brachioradialis muscle insertion is a reliable technique for coverage of a volar plate by slight distal transposition. In the repair of distal radius fractures, this may better protect the finger flexor tendons against irritation and/or rupture. That likelihood should now be studied.

Correction to: Insertion of the Ascension PyroCarbon PIP total joint in 152 human cadaver fingers: analysis of implant positions and malpositions.

In the experimental study the distal component of the Ascension PyroCarbon proximal interphalangeal total joint prosthesis was implanted 180° rotated. Figures 2-5 show the implant malpositions. The methods, results, and conclusion of the study were not affected by this.

[Elbow prostheses in rheumatic diseases]. / Ellenbogenprothese bei rheumatischen Erkrankungen.

When the elbow is destroyed due to rheumatic diseases, the joint can be replaced by a prosthesis and total arthroplasty. Improved pharmaceutical treatment for rheumatic diseases has, however, reduced the number of implantations in these patients. Reported 10-year survival rates of the implant currently achieve 81-90%.; however, due to limited long-term survival of the implant and high complication rates, total elbow arthroplasty should still be used with caution. Continuous technical improvements in the available prostheses and in surgical techniques could lead in the future to a decline in complications, such as aseptic loosening and infections.

[The proximal radioulnar joint in consideration of the distal radioulnar joint]. / Das proximale Radioulnargelenk unter Berücksichtigung des distalen Radioulnargelenks.

The movement of the forearm follows a complex interplay of three main components: the proximal and distal radioulnar joint and the interosseous membrane. Injuries to one or even all components have a huge impact on the integrity of this system. The Essex-Lopresti lesion presented a high challenge in clinical diagnostics as well as therapy. Reconstructions of the length and stability are essential for a satisfactory postoperative outcome. If a reconstruction of the radial head by osteosynthesis is not possible, a radial head prosthesis should be implanted in the case of longitudinal instability - avoiding overlapping and/or oversizing. The reconstruction of the interosseous membrane should be considered, as well as the assessment of the distal radioulnar joint and/or the triangular fibrocartilage complex. Various reconstruction options are available in this regard.

[Ligamentous lesions and instability of the finger joints]. / Ligamentäre Verletzungen und Bandinstabilitäten der Fingergelenke.

Joint capsule and ligamentous lesions are common injuries of the upper extremities. Athletes are particularly inclined to suffer from these injuries. Clinical and radiological examinations are the cornerstone of an adequate treatment. Ultrasound-based diagnostics as a non-invasive and dynamic investigation method are gaining increasing relevance based on the development of high resolution probes. A correct interpretation of the findings is only feasible with a comprehensive knowledge of the anatomy. The most important goal is stability as a prerequisite for early active and passive motion with unrestricted range of motion.

[Anatomy and biomechanics of the distal radioulnar joint]. / Anatomie und Biomechanik des distalen Radioulnargelenks.

BACKGROUND: The functionality of the upper extremity is decisively based on rotation of the forearm. The rotation depends on the extent of motion of the distal radioulnar joint. Rotation enables complete and focused usability of the hand in order to cope with daily activities. The configuration of the distal radioulnar joint has developed over millions of years of evolution. ANATOMIC CONDITIONS: The triangular fibrocartilage complex is the crucial stabiliser of the latter joint since osseous structures are limited. The palmar and dorsal radioulnar ligaments belong to this complex. The superficial and deep parts of the latter ligaments insert both centrically in accordance to the axis of rotation and eccentrically. This arrangement guarantees stability of the joint throughout pronosupination. The interosseous membrane is a further relevant stabiliser that guarantees sufficient load transmission from radius to ulna. The distal oblique bundle of the interosseous membrane is outstanding in this context. The pronator quadratus muscle is the relevant dynamic stabiliser of the distal radioulnar joint. Contraction of the muscle prevents diastasis of the joint. The deep head of the muscle is always activated during pronosupination.