[Treatment of symptomatic end-stage osteoarthritis of the ankle with anterolateral approach and an anatomical plate]. / Sprunggelenkarthrodese über einen anterolateralen Zugang mit einer anatomischen Platte.

OBJECTIVE: The aim of this paper is to describe the anterolateral approach using an anatomical plate for ankle arthrodesis and to present the first mid-term results with this technique in a high-risk population. INDICATIONS: The indication for arthrodesis of the ankle joint with this described technique is moderate to severe osteoarthritis of the ankle. CONTRAINDICATIONS: In addition to the general contraindications typical of any operation, there is a specific contraindication in cases of active infection of the soft tissues and accompanying osteomyelitis at the ankle. SURGICAL TECHNIQUE: The incision is made along the course of the peroneus tertius muscle. After that, the mobilization of the peroneus superficialis nerve is carried out, followed by the mobilization of the long extensor tendons, especially the extensor digitorum muscle in a medial direction opening the capsule and removal of the residual cartilage on the distal tibia and talus. Subsequently, the subchondral sclerosis is opened, and the implantation of a suitable osteosynthesis material, e.g., an anatomical angle-stable plate, is carried out. Finally, wound closure is performed involving the muscle belly of the extensor digitorum muscle covering the plate. POSTOPERATIVE MANAGEMENT: Immobilization of the ankle for 5-7 days in a dorsal knee-high splint. Retention in a walker after decongestion for another 5 weeks. Increased loading can be done after X­ray/computed tomography (CT) control from the 6th week. RESULTS: In all, 11 patients were observed retrospectively for an average of 14 months. There were no complications. The European Foot and Ankle Society (EFAS) score improved significantly from 3.3 to 17.8 points. All patients were subjectively satisfied with the result and would have the operation again.

Biomechanical Comparison of Medio-Plantar and Plantar Plate Fixation for First Tarsometatarsal Joint Arthrodesis.

Plantar plate positioning has been demonstrated as biomechanically superior. However, some operators remain resentful about the morbidity of the surgical approach. To provide improved plate fixation for first tarsometatarsal joint arthrodesis with respect to the tibialis anterior tendon, a medio-plantar plate was developed. The purpose of this biomechanical study was to compare its construct stability to that of a plantar plate construct. Twelve pairs of fresh frozen human specimens were used in a matched pair test. Each pair was fixed with a 4 mm compression screw and either a plantar locking plate or a medio-plantar locking plate. A cantilever beam test was performed in dorsiflexion. Before and after cyclic loading (5000 cycles; 40 N), bending stiffness and relative movements at the joint space were monitored in a quasi-static test including optical motion tracking. Maximum load and bending moment to failure were investigated in a load-to-failure ramp test. The bending stiffness of both groups did not significantly differ before (plantar 49.9 N/mm ± 19.2; medio-plantar 53.9 N/mm ± 25.4, p = 0.43) or after (plantar 24.4 N/mm ± 9.7; medio-plantar 35.3 N/mm ± 22.0, p = 0.08) cyclic loading but decreased significantly in both groups (p < 0.01) after cyclic loading. Relative movement increased significantly during cyclic testing in both groups (p < 0.01) but did not differ significantly between the groups before (p = 0.29) or after (p = 0.16) cyclic loading. Neither load nor bending moment to failure were significantly different (plantar 225 N ± 78, 10.8 Nm; medio-plantar 210 N ± 86, 10.1 Nm, p = 0.61). Both plate constructs provided equivalent construct stability, both being well suited for Lapidus arthrodesis.

The Correction Potential of the Lateral Release of the Hallux Valgus: A Comparative Anatomical Study of Minimally Invasive Versus Open Surgical Technique Using a Dorsal Approach.

Background: Lateral release (LR) is an integral part of surgical correction of hallux valgus. A comparison was made between the open and minimally invasive LR techniques using a dorsal approach. The reliability and safety of the two methods were compared. Besides, the release of specific structures was investigated with special emphasis on ascertaining if the release was partial or a total one. Methods: In this study on cadavers, LR was performed on nine pairs of foot and ankle specimens. The group assignments were randomized for each case. The operations were followed by anatomical preparation, data collection, photo documentation, and statistical analysis. Results: A statistically significant advantage was observed with the open dorsal approach as there was a complete release of the adductor hallucis muscle from the lateral sesamoid and the lateral metatarsosesamoid ligament (p = 0.015 in each case). In terms of releasing the adductor hallucis muscle from the proximal phalanx, the lateral joint capsule, and the lateral collateral ligament, none of the investigated procedures showed better performance. However, open dorsal access tends to show a higher degree of release more frequently. Conclusions: Splitting of the lateral joint capsule, including the lateral collateral ligament and lateral metatarsosesamoid ligament via the dorsal approach can be performed reliably and completely using the open surgical technique. The open dorsal technique shows better rates of detachment when the adductor hallucis muscle is released from the lateral sesamoid. Both techniques resulted in incomplete release of the adductor hallucis muscle from the proximal phalanx. Study Type: Therapeutic-investigating the results of a treatment. Level of Evidence: II (Prospective cohort study). Supplementary Information: The online version contains supplementary material available at 10.1007/s43465-021-00575-3.

Iatrogenic Damage to Neurovascular and Soft Tissue Structures During Lateral Release of Hallux Valgus: A Comparative Anatomical Study of Minimally Invasive Versus Open Surgical Techniques.

Lateral release is often an integral step in surgical correction of hallux valgus and can be performed using open or minimally invasive techniques. We investigated whether these techniques cause iatrogenic damage to arteries, nerves, tendons, or joint capsules. In this cadaver study, lateral release was performed on 9 pairs of specimens by a specialized foot surgeon. The specimens were randomly assigned to each group. The operations were followed by anatomical preparation, data collection, photo documentation, and statistical analysis. Iatrogenic damage to arteries, nerves, tendons, or joint capsules was rare, regardless of the surgical technique used. However, with the minimally invasive technique, the tendon of the extensor hallucis longus muscle and the sensitive terminal branches of the fibular nerve were at risk due to their anatomical proximity to the access portal. The deep transverse metatarsal ligament was potentially at risk if the adductor hallucis muscle was completely detached from the lateral sesamoid. When the deep transverse metatarsal ligament was transected there was risk of damaging the underlying plantar neurovascular structures. Both surgical techniques are safe in terms of the risk of injury to neighboring neurovascular and soft tissue structures.

Anatomical Study of Sinus Tarsi-Based Lateral Lengthening Calcaneal Osteotomy.

BACKGROUND: Lateral lengthening calcaneal osteotomy (LL-CO) is commonly performed as a treatment for an abducted midfoot in pes planovalgus deformity. The purpose of this study is to investigate potential damage to medial structures with a sinus tarsi LL-CO. METHODS: Sixteen cadaver feet were used. Eight feet had an extended lateral approach, and 8 had a limited lateral (sinus tarsi) approach. All underwent a sinus tarsi LL-CO. Specimens were then dissected to identify inadvertent injury to medial structures. RESULTS: Sinus tarsi LL-CO was associated with damage to the sustentaculum tali and medial articular facets in 56% and 62.5% of specimens, respectively. No anterior or posterior facet injuries were found, although 56% of specimens had a confluent medial and anterior facet. CONCLUSION: Damage to the medial articular facet and sustentaculum is possible with a flat cut sinus tarsi LL-CO due to the curved nature of the relevant sinus tarsi and canal anatomy. CLINICAL RELEVANCE: Sinus tarsi LL-CO needs to be performed with caution since damage to the subtalar joint is possible. LEVEL OF EVIDENCE: Level II, prospective cohort study.

[Description of a technique that uses Lapidus arthrodesis plus osteochondral autotransplantation in the treatment of severe hallux rigidus]. / Lapidusarthrodese in Kombination mit einer osteochondralen Autotransplantation in das Metatarsale-I-Köpfchen zur Behandlung der fortgeschrittenen Arthrose des Großzehengrundgelenkes.

OBJECTIVE: The objective of this technique is the treatment a severe hallux rigidus deformity by reorientation of an elevated first metatarsal using arthrodesis of the first tarsometatarsal joint and performing a one-step transplantation of an osteochondral graft, which is harvested from the first cuneiform, to the head of the first metatarsal bone. INDICATIONS: Severe arthritis of the first metatarsophalangeal joint (MTP) stage 3 and 4 in the Vanore classification. CONTRAINDICATIONS: General contraindications for a foot surgery; ankylosis of MTP joint; severe arthritis of the sesamoid joint; osteonecrosis; short first metatarsal; previous infection in the metatarsophalangeal joint; large cysts at the head of the first metatarsal. SURGICAL TECHNIQUE: The first step is the preparation of the metatarsophalangeal and the first tarsometatarsal joint. After mobilizing the first metatarsal in a medioplantar direction, a cartilage-bone cylinder is removed from the articular surface of the medial cuneiform using special osteochondral autograft transfer system (OATS) instruments (Small Joint OATS, Arthrex medical instruments GmbH, Munich, Germany). This is followed by the arthrodesis of the first tarsometatarsal joint with reorientation of the position of the first metatarsal bone. Then the removed osteochondral cylinder is implanted into the articular surface of the first metatarsal head. After that the capsule is closed and the skin sutured. POSTOPERATIVE MANAGEMENT: Postoperative management is guided mainly by the requirements of the first tarsometatarsal arthrodesis. When a plantar plate is used pain orientated full weightbearing is allowed in a postoperative shoe with a stiffened sole for 6-8 weeks. Physiotherapy is prescribed to exercise the first metatarsophalangeal joint. RESULTS: In the study, 5 patients were treated with the method described in the years 2011-2012 and were followed up for a period of 2 years. All of these patients were subjectively satisfied with the outcome of the operation. There were no relevant surgery-associated complications.

[Cartilage chip transplantation for cartilage defects of the first metatarsophalangeal joint]. / Minced Cartilage bei Knorpeldefekten am Großzehengrundgelenk.

OBJECTIVE: Treatment of circumscribed cartilage defects in the first metatarsophalangeal joint (MTP1) using autologous cartilage fragments. INDICATIONS: Full thickness cartilage defects (ICRS IV) or focal osteoarthritis in combination with hallux rigidus. CONTRAINDICATIONS: Pre-existing ankylosis of the metatarsophalangeal joint; global osteoarthritis of the joint; advanced osteoarthritis of the sesamoidal articulation; osteonecrotic cysts in the head of the first metatarsal bone. SURGICAL TECHNIQUE: Preparation of the metatarsophalangeal joint. Mobilization of the first metatarsal head. Harvesting of the cartilage fragments from the dorsal rim portion as part of the cheilectomy. Mincing the cartilage fragments with a 3.0 mm shaver in sterile conditions. Augmenting the cartilage fragments with autologous conditioned plasma (ACP). Preparing the defect area and creation of a "contained" defect. Replantation of the resulting minced cartilage mass into the defect of the articular surface on the first metatarsal head. POSTOPERATIVE MANAGEMENT: Immobilization of the MTP1 for 48 h. Intensive physiotherapy for 3 months. Full weight bearing after reduced swelling. RESULTS: In 2020, 5 patients were treated with the method described and followed up for a period of 1 year. All patients were subjectively satisfied with the result of the operation. There were no relevant surgery-associated complications.

Arthroscopic Minced Cartilage Implantation for Chondral Lesions at the Talus: A Technical Note.

In the past few years, autologous chondrocyte implantation has been shown to be the most suitable cartilage reconstructive technique with the best tissue quality. Although this method is part of the standard surgical repertoire in the knee joint, it has so far not been an established method in the ankle because there are no prospective randomized controlled studies to prove a significant advantage over alternative methods of cartilage repair. The methods most frequently used in this context (e.g., marrow stimulation techniques) can, however, at most generate hyaline-like and thus biomechanically inferior regenerates. Minced cartilage implantation, on the other hand, is a relatively simple and cost-effective 1-step procedure with promising biological potential and-at least in the knee joint-satisfactory clinical results. We present an arthroscopic surgical technique by which the surgeon can apply autologous chondrocytes in a 1-step procedure (AutoCart; Arthrex, Munich, Germany) to treat articular cartilage defects in the ankle joint.

Comparison of Ligament-Repair Techniques for the Syndesmosis: A Simulated Cadaveric Weight-Bearing Computed Tomography Analysis.

Although the literature describes a variety of reconstructive techniques for the syndesmosis, only few studies offer comparative data. Therefore, the authors compared 2 different ligament repair techniques for the syndesmosis. Sixteen paired fresh-frozen human cadaveric lower limbs were embedded in polymethyl methacrylate mid-calf and placed in a custom-made weightbearing simulation frame. Computed tomography scans of each limb were obtained in a simulated foot-flat loading (75N) and single-leg stance (700N) in 5 different foot positions (previously reported data). One of each pair was then reconstructed via 1 of 2 methods: a free medial Achilles tendon autograft or a long peroneal tendon ligament repair. The specimens were rescanned, compared with their respective intact states and directly with each other. Measurements of fibular diastasis, rotation, anteroposterior translation, mediolateral translation, and fibular shortening were performed on the axial cuts of the computed tomography scans, 1 cm proximal to the roof of the plafond. There was no significant difference in fibular positioning with direct comparison of the reconstructions. Comparisons with their respective intact states, however, showed differences in their abilities to control reduction, most notably in the externally rotated and dorsiflexed positions of the foot. Neither reconstruction was clearly superior in restoring physiologic conditions. Only with a comparison of each technique to its respective intact state were differences between the techniques revealed, a benefit of this particular testing method.

Computed Tomography Analysis for Quantification of Displacement of the Distal Fibula in Different Foot Positions With Weightbearing and Sequentially Increased Instability: An Anatomic Cadaveric Study on Syndesmosis.

Syndesmotic injuries are quite common, but accurate diagnosis and treatment can be difficult, in part because of individual anatomic variation and complex movements of the fibula in the incisura. The current cadaveric study was designed to investigate changes in the position of the fibula in the incisura during simulated weightbearing in different foot positions and with sequential sectioning of syndesmotic and deltoid ligaments. Sixteen paired, fresh-frozen cadaveric limbs were embedded in polymethylmethacrylate mid-calf and placed in a weightbearing simulation frame. Computed tomography scans were obtained while the legs were in a simulated foot-flat position (75 N) and single-leg stance (700 N) in 5 foot positions: neutral, 15° external rotation, 15° internal rotation, 20° dorsiflexion, and 20° plantar flexion. The anterior-inferior tibiofibular ligament, posterior tibiofibular ligament complex, deltoid, and interosseous membranes were sectioned sequentially and rescanned. Measurements of fibular diastasis, rotation, anterior-posterior and medial-lateral translation, and fibular shortening were performed. The most destructive state resulted in the largest displacement at the syndesmosis. The degree of subluxation in all ligament states was dependent on the foot position. External rotation created statistically significant displacement at all levels of injury. There were no significant differences between sides of the same donor. Our data demonstrate the importance of foot position in reduction at the syndesmosis under weightbearing. The current ex vivo model could be used to evaluate other aspects of this injury or the value of reconstructive techniques in the future.

A role for APP in Wnt signalling links synapse loss with ß-amyloid production.

In Alzheimer's disease (AD), the canonical Wnt inhibitor Dickkopf-1 (Dkk1) is induced by ß-amyloid (Aß) and shifts the balance from canonical towards non-canonical Wnt signalling. Canonical (Wnt-ß-catenin) signalling promotes synapse stability, while non-canonical (Wnt-PCP) signalling favours synapse retraction; thus Aß-driven synapse loss is mediated by Dkk1. Here we show that the Amyloid Precursor Protein (APP) co-activates both arms of Wnt signalling through physical interactions with Wnt co-receptors LRP6 and Vangl2, to bi-directionally modulate synapse stability. Furthermore, activation of non-canonical Wnt signalling enhances Aß production, while activation of canonical signalling suppresses Aß production. Together, these findings identify a pathogenic-positive feedback loop in which Aß induces Dkk1 expression, thereby activating non-canonical Wnt signalling to promote synapse loss and drive further Aß production. The Swedish familial AD variant of APP (APPSwe) more readily co-activates non-canonical, at the expense of canonical Wnt activity, indicating that its pathogenicity likely involves direct effects on synapses, in addition to increased Aß production. Finally, we report that pharmacological inhibition of the Aß-Dkk1-Aß positive feedback loop with the drug fasudil can restore the balance between Wnt pathways, prevent dendritic spine withdrawal in vitro, and reduce Aß load in vivo in mice with advanced amyloid pathology. These results clarify a relationship between Aß accumulation and synapse loss and provide direction for the development of potential disease-modifying treatments.

Amyloid ß synaptotoxicity is Wnt-PCP dependent and blocked by fasudil.

INTRODUCTION: Synapse loss is the structural correlate of the cognitive decline indicative of dementia. In the brains of Alzheimer's disease sufferers, amyloid ß (Aß) peptides aggregate to form senile plaques but as soluble peptides are toxic to synapses. We previously demonstrated that Aß induces Dickkopf-1 (Dkk1), which in turn activates the Wnt-planar cell polarity (Wnt-PCP) pathway to drive tau pathology and neuronal death. METHODS: We compared the effects of Aß and of Dkk1 on synapse morphology and memory impairment while inhibiting or silencing key elements of the Wnt-PCP pathway. RESULTS: We demonstrate that Aß synaptotoxicity is also Dkk1 and Wnt-PCP dependent, mediated by the arm of Wnt-PCP regulating actin cytoskeletal dynamics via Daam1, RhoA and ROCK, and can be blocked by the drug fasudil. DISCUSSION: Our data add to the importance of aberrant Wnt signaling in Alzheimer's disease neuropathology and indicate that fasudil could be repurposed as a treatment for the disease.

Influence of tibialis posterior muscle activation on foot anatomy under axial loading: A biomechanical CT human cadaveric study.

BACKGROUND: Collapse of the medial longitudinal arch and subluxation of the subtalar joint are common occurrences in adult flatfoot deformity. Controversy exists about the role of the tibialis posterior (TP) tendon as first and/or essential lesion. Subtle changes in the foot configuration can occur under weight bearing. PURPOSE: This human cadaveric study is designed to investigate the effect that isolated actuation of the TP tendon has on the medial longitudinal arch and the hindfoot configuration under simulated weight bearing. METHODS: A radiolucent frame was developed to apply axial loading on cadaveric lower legs during computer tomography (CT) examinations. Eight pairs of fresh-frozen specimens were imaged in neutral position under foot-flat loading (75N) and under single-leg stance weight bearing (700N) without and with addition of 150N pulling force on the TP tendon. Measurements of subtalar joint subluxation, forefoot arch angle and talo-first metatarsal angle were conducted on each set of CT scans. RESULTS: Subtalar subluxation, talo-first metatarsal angle and talo-navicular coverage angle significantly increased under single-leg stance weight bearing, whereas forefoot arch angle significantly decreased. Actuation of the TP tendon under weight bearing did not restore the forefoot arch angle or correct subtalar subluxation and talo-metatarsal angle. CONCLUSION: Significant effect that weight bearing has on the medial longitudinal arch and the subtalar joint configuration is demonstrated in an ex-vivo model. In absence of other medial column derangement, actuation of the TP tendon alone does not seem to reconstitute the integrity of the medial longitudinal arch or correct the hindfoot subluxation under weight bearing. CLINICAL RELEVANCE: The findings of this study together with the developed model for ex-vivo investigation provide a further insight in foot anatomy.

[Fractures of the ankle joint in elderly patients]. / Frakturen des oberen Sprunggelenks beim älteren Patienten.

The number of ankle fractures in elderly patients is increasing. The aim of treatment of ankle fractures in the elderly is to guarantee a possible unlimited autonomy and quality of life for patients. This is achieved by minimization of the complications and impairments after ankle joint fractures. Decisive for the further course is the initial treatment. The results are essentially determined by the soft tissue management, reduction and stable osteosynthesis; however, an orthogeriatric co-management with the implementation of treatment paths and standard operating procedures is recommended. The advantages of an interdisciplinary cooperation of trauma surgeons and geriatricians are obvious in this situation.

Biomechanical investigation of two plating systems for medial column fusion in foot.

BACKGROUND: Arthrodesis of the medial column (navicular, cuneiform I and metatarsal I) is performed for reasons such as Charcot arthropathy, arthritis, posttraumatic reconstruction or severe pes planus. However, the complication rate is still high and mainly resulting from inadequate fixation. Special plates, designed for medial column arthrodesis, seem to offer potential to reduce the complication rate. The aim of this study was to investigate biomechanically plantar and dorsomedial fusion of the medial column using two new plating systems. METHODS: Eight matched pairs of human cadaveric lower legs were randomized in two groups and medial column fusion was performed using either plantar or dorsomedial variable-angle locking compression plates. The specimens were biomechanically tested under cyclic progressively increasing axial loading with physiological profile of each cycle. In addition to the machine data, mediolateral x-rays were taken every 250 cycles and motion tracking was performed to determine movements at the arthrodesis site. Statistical analysis of the parameters of interest was performed at a level of significance p = 0.05. RESULTS: Displacement of the talo-navicular joint after 1000, 2000 and 4000 cycles was significantly lower for plantar plating (p≤0.039) while there was significantly less movement in the naviculo-cuneiform I joint for dorsal plating post these cycle numbers (p<0.001). Displacements in all three joints of the medial column, as well as angular and torsional deformations between the navicular and metatarsal I increased significantly for each plating technique between 1000, 2000 and 4000 cycles (p≤0.021). The two plating systems did not differ significantly with regard to stiffness and cycles to failure (p≥0.171). CONCLUSION: From biomechanical point of view, although dorsomedial plating showed less movement than plantar plating in the current setup under dynamic loading, there was no significant difference between the two plating systems with regard to stiffness and cycles to failure. Both tested techniques for dorsomedial and plantar plating appear to be applicable for arthrodesis of the medial column of the foot and other considerations, such as access morbidity, associated deformities or surgeon's preference, may also guide the choice of plating pattern. Further clinical studies are necessary before definitive recommendations can be given.

Reconstruction of the lateral tibia plateau fracture with a third triangular support screw: A biomechanical study.

BACKGROUND: Split fractures of the lateral tibia plateau in young patients with good bone quality are commonly treated using two minimally invasive percutaneous lag screws, followed by unloading of the knee joint. Improved stability could be achieved with the use of a third screw inserted either in the jail-technique fashion or with a triangular support screw configuration. The aim of this study was to investigate under cyclic loading the compliance and endurance of the triangular support fixation in comparison with the standard two lag-screw fixation and the jail technique. METHODS: Lateral split fractures of type AO/OTA 41-B1 were created on 21 synthetic tibiae and subsequently fixed with one of the following three techniques for seven specimens: standard fixation by inserting two partially threaded 6.5 mm cannulated lag screws parallel to each other and orthogonal to the fracture plane; triangular support fixation-standard fixation with one additional support screw at the distal end of the fracture at 30° proximal inclination; and jail fixation-standard fixation with one additional orthogonal support screw inserted in the medial nonfractured part of the bone. Mechanical testing was performed under progressively increasing cyclic compression loading. Fragment displacement was registered via triggered radiographic imaging. RESULTS: Mean construct compliance was 3.847 × 10-3 mm/N [standard deviation (SD) 0.784] for standard fixation, 3.838 × 10-3 mm/N (SD 0.242) for triangular fixation, and 3.563 × 10-3 mm/N (SD 0.383) for jail fixation, with no significant differences between the groups (p = 0.525). The mean numbers of cycles to 2 mm fragment dislocation, defined as a failure criterion, were 12,384 (SD 2267) for standard fixation, 17,708 (SD 2193) for triangular fixation, and 14,629 (SD 5194) for jail fixation. Triangular fixation revealed significantly longer endurance than the standard one (p = 0.047). CONCLUSION: Triangular support fixation enhanced interfragmentary stability at the ultimate stage of dynamic loading. However, the level of improvement seems to be limited and may not legitimate the intervention with an additional third screw.

Lateral soft-tissue release through a medial incision: Anatomic comparison of two techniques.

BACKGROUND: The distal soft tissue procedure is an integral part of hallux valgus surgery, providing soft tissue balance and alignment restoration of the first metatarsophalangeal joint. Various approaches have been established to this end. For techniques that do not include a separate dorsal incision, lateral release may be achieved via a transarticular approach or via a medial incision and a dorsal flap over the first metatarsal. Compared to the double-incision technique, these techniques are not only cosmetically superior and thus meet the demands of most surgeons and patients. MATERIAL AND METHODS: Using six pairs of frozen cadaveric feet, lateral release was performed using one of the above techniques in a randomized manner with pair comparison. The specimens were then dissected and the completeness of the release as well as any damage to anatomic structures was documented. RESULTS: The transarticular technique enabled complete release of the metatarsal-sesamoid suspensory ligament (MSL) and the transverse and oblique head of the adductor hallucis muscle in five of six specimens. The comparative technique enabled the same in only two of six cases for the adductor hallucis muscle and in four cases for the MSL. The transarticular approach achieved complete release of the lateral joint capsule in three of six specimens, whereas the dorsal approach achieved no release in any specimen. Neither of the methods caused any macroscopic injury to the surfaces of the first metatarsophalangeal joint. The examined arteries, veins, and nerves remained intact in all specimens treated with the transarticular approach, but dorsal release resulted in one documented injury to the first dorsal metatarsal artery and its concomitant veins. CONCLUSIONS: Compared to release by dissection superficially to the extensor tendons, transarticular release provides a more complete lateral release and less injuries to neurovascular bundles. Further anatomic and clinical studies are needed, however, before conclusive recommendations can be made.

First Tarsometatarsal Arthrodesis: An Anatomic Evaluation of Dorsomedial Versus Plantar Plating.

Fusion of the first tarsometatarsal joint is a widely used procedure for the correction of hallux valgus deformity. Although dorsomedial H-shaped plating systems are being increasingly used, fusion can also be achieved by plantar plating. The goal of the present study was to compare these 2 operative techniques based on the anatomic considerations and show the potential pitfalls of both procedures. Six pairs of deep-frozen human lower legs were used in the present cadaveric study. In a randomized manner, either dorsomedial arthrodesis or plantar plating through a medial incision was performed. With regard to arterial injury, the plantar technique resulted in fewer lesions (plantar, 4 injuries [66.7%] to the terminal branches of the first digital branch of the medial plantar artery; dorsomedial, 3 injuries [50%] to the main trunks of the plantar metatarsal arteries and the first dorsal metatarsal artery). With respect to injury to the veins, the plantar procedure affected significantly fewer high-caliber subcutaneous trunk veins. The nerves coursing through the operative field, such as the saphenous and superficial fibular nerves, were compromised more often by the dorsal approach. Neither the plantar plating nor the dorsomedial plating technique was associated with injury to the insertion of the tibialis anterior muscle. Both studied techniques are safe, well-established procedures. Arthrodesis with plantar plating, however, offers additional advantages and is a reliable tool in the foot and ankle surgeon's repertoire.

A biomechanical comparison of fixed angle locking compression plate osteosynthesis and cement augmented screw osteosynthesis in the management of intra articular calcaneal fractures.

PURPOSE: The purpose of this study was to investigate whether cement-augmented screw osteosynthesis results in stability comparable to conventional fixed-angle locking plate osteosynthesis using cadaveric bones to model a Sanders type 2B fracture. METHODS: Seven pairs of fresh frozen human calcanei and the corresponding tali were used. The specimens were assigned pairwise to two study groups in a randomised manner. In order to determine the initial quasi-static stiffness of the bone-implant construct, testing commenced with quasi-static compression ramp loading; subsequently, sinusoidal cyclic compression loading at 2 Hz was performed until construct failure occurred. Initial dynamic stiffness (cycle 1), range of motion (ROM), cycles to failure and load to failure were determined from the machine data during the cyclic test. In addition, at 250-cycle intervals, Böhler's angle and the critical angle of Gissane were determined on mediolateral X-rays shot with a triggered C-arm; 5° angle flattening was arbitrarily defined as a failure criterion. RESULTS: Bone mineral density was normally distributed without significant differences between the groups. The augmented screw osteosynthesis resulted in higher stiffness values compared to the fixed-angle locking plate osteosynthesis. The fracture fragment motion in the locking plate group was significantly higher compared to the group with augmented screw osteosynthesis. CONCLUSIONS: The results of this study indicate that in our selected test set-up augmented screw osteosynthesis was significantly superior to the conventional fixed-angle locking plate osteosynthesis with respect to primary stability and ROM during cyclic testing.