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.

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.

Intramuscular architecture of the autochthonous back muscles in humans.

Many training concepts take muscle properties such as contraction speed or muscle topography into account to achieve an optimal training outcome. Thus far, the internal architecture of muscles has largely been neglected, although it is well known that parameters such as pennation angles or the lengths of fascicles but also the proportions of fleshy and tendinous fascicle parts have a major impact on the contraction behaviour of a muscle. Here, we present the most detailed description of the intramuscular fascicle architecture of the human perivertebral muscles available so far. For this, one adult male cadaver was studied. Our general approach was to digitize the geometry of each fascicle of the muscles of back proper (Erector spinae) - the Spinalis thoracis, Iliocostalis lumborum, Longissimus thoracis and the Multifidus thoracis et lumborum - and of the deep muscles of the abdomen - Psoas minor, Psoas major and Quadratus lumborum - during a layerwise dissection. Architectural parameters such as fascicle angles to the sagittal and the frontal planes as well as fascicle lengths were determined for each fascicle, and are discussed regarding their consequences for the function of the muscle. For example, compared with the other dorsovertebral muscles, the Longissimus thoracis can produce greater shortening distances because of its relatively long fleshy portions, and it can store more elastic energy due to both its relatively long fleshy and tendinous fascicle portions. The Quadratus lumborum was outstanding because of its many architectural subunits defined by distinct attachment sites and fascicle lengths. The presented database will improve biomechanical models of the human trunk by allowing the incorporation of anisotropic muscle properties such as the fascicle direction into finite element models. This information will help to increase our understanding of the functionality of the human back musculature, and may thereby improve future training concepts.

Imaging of lamination patterns of the adult human olfactory bulb and tract: in vitro comparison of standard- and high-resolution 3T MRI, and MR microscopy at 9.4 T.

PURPOSE: Neurological and smelling disorders (e.g. Alzheimer's disease, sinonasal disease) negatively affect the microstructural integrity of the olfactory bulb's (OB) cortical layers. Recovery processes depend on active restoration of this microstructural integrity enabled by neuroneogenesis in the OB. The aim of this study was to evaluate lamination patterns of the OB and adjacent tract (OT) using high resolution MRI at 3 Tesla (T) as well as MR microscopy at 9.4 T in comparison with histological sections. MATERIAL AND METHODS: Twenty-four human OBs were imaged in vitro using standard (2mm slice thickness) and high resolution (0.2mm slice thickness) T1w and T2w MR imaging at 3T. Based on signal intensity differences, the number of OB layers and the OB lamination patterns were assessed by two observers in consensus. Results were compared using Wilcoxon test. Signal intensity profiles were compared to reference Nissl stained histological sections and imaging results of MR microscopy. OT lamination patterns were assessed and different configurations of cross sectional areas were compared to macroscopic results and OB/OT lamination patterns. RESULTS: Standard resolution at 3T identified three layers in 8.3%, two layers in 83.3%, and one layer in 8.3%. High resolution at 3T (4 layers in 91.7%, 3 layers in 8.3%) significantly performed better (P<0.001). Signal intensity profile analysis at 3T and 9.4 T (yielding up to 6 different signal intensities) correlated with histological sections and enabled quantitative evaluation of OB lamination patterns. 3T MRI of the OT revealed two separate signal intensities in T2w in 73%, a hyperintense core and a hypointense sheath, and the number of OT signal intensities positively correlated (ρ=0.541, P=0.006) with the increasing complexity of the OTs' cross sectional area configurations. Additionally, cross sectional area configurations correlated with macroscopic results (ρ=0.558, P=0.002) and OB lamination patterns (ρ=0.446, P=0.022). CONCLUSIONS: 3T MRI and MR-microscopy indicate the possibility to identify the lamination pattern of the human OB/OT and to reflect the histological status. If further development will be able to provide technical equipment that complies with the condition of human in vivo high resolution imaging achieving a good enough signal noise ratio, the method of signal intensity profile analysis could prospectively enable scientists to assess the OB's microstructural status in neurological and smelling disorders.

Feasibility study of semi-automated measurements of finger joint space widths.

The purpose of this study is to evaluate technical feasibility based on image capturing conditions (film-focus distance (FFD), film sensitivity, film brand, exposure level and tube voltage) that potentially alter radiographs and consequently may influence the semi-automated measurement of joint space distance (JSD) by computer-aided joint space analysis (CAJSA) in rheumatoid arthritis and osteoarthritis. The radiographs of a left hand (deceased man) were acquired under systematically changing image capturing conditions (exposure level: 4-8 mAs; FFD: 90-130 cm; film sensitivity: 200/400 and tube voltage: 40-52 kV with different image modalities: conventional radiographs, original digital radiographs, digital print-outs). All JSD-measurements were performed with the CAJSA-technology (Radiogrammetry Kit, Version 1.3.6; Sectra; Sweden) at the metacarpal-phalangeal articulation. JSD-analysis was not influenced by changes of FFD, exposure level, film sensitivity or film brand. JSD showed significant variation caused by tube voltage (conventional: CV = 1.913% for Agfa and CV = 2.448% for Kodak; digital: CV = 0.741% for Philips print-outs and CV = 0.620% with original digital images versus CV = 2.185% for Siemens print-outs and 0.951% with original digital images). Computer-aided joint space analysis for JSD-measurements is unaffected by the following image capturing parameters: film-focus distance, film sensitivity, film brand and exposure level. An influence of tube voltage was detected in a lesser extent for original digital images compared to the printed digital as well as conventional versions. Consequently, a standardized tube voltage is essential for accurate reproductions of CAJSA-measurements in rheumatoid arthritis and osteoarthritis.

Plantar versus dorsomedial locked plating for Lapidus arthrodesis: a biomechanical comparison.

BACKGROUND: Lapidus arthrodesis with a plate and a compression screw is an established procedure in hallux valgus surgery. The present study was performed to investigate the potential benefit of a compression screw combined with a plantarly applied angle-stable, anatomically precontoured plate or a dorsomedially applied angle-stable plate. METHODS: In six pairs of human cadaver specimens, one specimen each was randomized to receive a dorsomedial H-shaped plate, while the other received a plantar plate. Bone mineral density was measured with peripheral quantitative computed tomography. The specimens were loaded quasi-statically, followed by cyclic loading. Finally, they were loaded to failure. In the static tests, stiffness and range of motion (ROM) data were obtained. In the cyclic tests, the constructs' displacement was studied. In the load-to-failure test, stiffness and maximum load to failure were measured. RESULTS: The two groups did not differ significantly with regard to BMD (p = 0.25). Any significant differences observed were in favor of the plantar constructs, which had greater initial stiffness (p = 0.028) and final stiffness (p = 0.042), a smaller ROM (p = 0.028), and a greater load to failure (p = 0.043). There was no significant difference regarding displacement (p = 0.14). CONCLUSION: In the static tests, the plantar angle-stable plate construct was superior to the dorsomedial angle-stable plate construct. CLINICAL RELEVANCE: Plantar plating appears to offer biomechanical benefit. Clinical studies will be required to show whether this translates into earlier resumption of weightbearing and into lower rates of nonunion.

A biomechanical comparison of a biodegradable volar locked plate with two titanium volar locked plates in a distal radius fracture model.

BACKGROUND: Volar plating is commonly used in the management of distal radius fractures; bioresorbable plates have attractive features. We compared a bioresorbable plate with a latest generation and an established locked titanium plate. METHODS: Twenty-four fresh-frozen radii (12 pairs) were assigned to three mean bone mineral density-matched groups of eight radii each. A standardized extraarticular distal radius fracture was created and plated using one implant type per group. Postplating stiffness and displacement were studied in a first axial-loading test (15 cycles at 250 N). Next, biodegradation was simulated by 4 weeks' immersion in phosphate-buffered saline, followed by a second axial test. Finally, the specimens underwent cyclic loading (2,400 cycles at 250 N). RESULTS: It is clear from the initial test that the LCP plate was significantly stiffer and displaced less than the bioresorbable plate. The outcome of the postimmersion tests is that one bioresorbable plate failed early on after 4 weeks' immersion, and the remaining bioresorbable plates and the T plates did not differ significantly. Cyclic tests conclude that the LCP plate was significantly superior to the other systems. One T plate and four of the bioresorbable plates failed, but none of the LCP plates failed. In the bioresorbable constructs, stability, time to failure, and bone mineral density were significantly correlated. CONCLUSIONS: The LCP plate was biomechanically superior and may be generally recommended for the volar plating of distal radius fractures. Except one plate failure, the bioresorbable plate was similar to the T plate in the quasi-static tests and should, therefore, be considered for clinical studies, with patient selection confined, initially, only to candidates with good bone stock quality.

Stability of medial locking plate and compression screw versus two crossed screws for lapidus arthrodesis.

BACKGROUND: Lapidus (first metatarsocuneiform joint) arthrodesis is an established procedure for the management of hallux valgus. This study investigated the utility of fixation with a medial locking plate with adjunct compression screw versus fixation with two crossed screws. MATERIALS AND METHODS: Eight pairs of fresh-frozen human specimens were used in a matched pair test. Bone mineral density (BMD) was measured with peripheral quantitative computed tomography (pQCT). Fixation with two 4-mm-diameter crossed screws was compared versus a medial locking plate (X-Locking Plate 2.4/2.7; Synthes, Solothurn, Switzerland) with adjunct 4-mm-diameter compression screw. The specimens were tested in a four-point bending test. Parameters obtained were initial stiffness; plantar joint-line gapping after one cycle, 100 and 1000 cycles; and number of cycles to failure. Failure was defined as more than or equal to 3 mm plantar gapping. RESULTS: The groups did not differ significantly with regard to BMD (p = 0.866) and initial stiffness (p = 0.889). The plate-and-screw construct showed significantly less movement during testing, and significantly (p = 0.001) more cycles to failure than did the crossed-screw construct. There was a significant correlation (crossed-screw construct: p = 0.014; plate-and-screw construct: p = 0.010) between BMD and the number of cycles to failure. CONCLUSION: Under cyclic loading conditions, the construct using a medial locking plate with adjunct compression screw was superior to the construct using two crossed screws. CLINICAL RELEVANCE: The medial locking-plate technique described could help shorten the period of nonweightbearing and reduce the risk of non-union.

Temperature influence on DXA measurements: bone mineral density acquisition in frozen and thawed human femora.

BACKGROUND: Determining bone mineral density (BMD) with dual-energy x-ray absorptiometry (DXA) is an established and widely used method that is also applied prior to biomechanical testing. However, DXA is affected by a number of factors. In order to delay decompositional processes, human specimens for biomechanical studies are usually stored at about -20 degrees C; similarly, bone mineral density measurements are usually performed in the frozen state. The aim of our study was to investigate the influence of bone temperature on the measured bone mineral density. METHODS: Using DXA, bone mineral density measurements were taken in 19 fresh-frozen human femora, in the frozen and the thawed state. Water was used to mimic the missing soft tissue around the specimens. Measurements were taken with the specimens in standardized internal rotation. Total-BMD and single-BMD values of different regions of interest were used for evaluation. RESULTS: Fourteen of the 19 specimens showed a decrease in BMD after thawing. The measured total-BMD of the frozen specimens was significantly (1.4%) higher than the measured BMD of the thawed specimens. CONCLUSION: Based on our findings we recommend that the measurement of bone density, for example prior to biomechanical testing, should be standardized to thawed or frozen specimens. Temperature should not be changed during measurements. When using score systems for data interpretation (e.g. T- or Z-score), BMD measurements should be performed only on thawed specimens.

Comparison of calcaneal fixation of a retrograde intramedullary nail with a fixed-angle spiral blade versus a fixed-angle screw.

BACKGROUND: Retrograde intramedullary nailing is an established technique for tibiotalocalcaneal arthrodesis (TTCA). In poor bone stock (osteoporosis, neuroarthropathy), device fixation in the hindfoot remains a problem. Fixed-angle spiral-blade fixation of the nail in the calcaneus could be useful. MATERIALS AND METHODS: In seven matched pairs of human below-knee specimens, bone mineral density (BMD) was determined, and TTCA was performed with an intramedullary nail (Synthes Hindfoot Arthrodesis Nail HAN Expert Nailing System), using a conventional screw plus a fixed-angle spiral blade versus a conventional screw plus a fixed-angle screw, in the calcaneus. The constructs were subjected to quasi-static loading (dorsiflexion/plantarflexion, varus/valgus, rotation) and to cyclic loading to failure. Parameters studied were construct neutral zone (NZ) and range of motion (ROM), and number of cycles to failure. RESULTS: With dorsiflexion/plantarflexion loading, the screw-plus-spiral-blade constructs had a significantly smaller ROM in the quasi-static test (p = 0.028) and early in the cyclic test (p = 0.02); differences in the other parameters were not significant. There was a significant correlation between BMD and cycles to failure for the two-screw constructs (r = 0.94; p = 0.002) and for the screw-plus-spiral-blade constructs (r = 0.86; p = 0.014). CONCLUSION: In TTCA with a HAN Expert Nailing System, the use of a calcaneal spiral blade can further reduce motion within the construct. This may be especially useful in poor bone stock. CLINICAL RELEVANCE: Results obtained in this study could be used to guide the operating surgeon's TTCA strategy.

Biomechanical evaluation of plate osteosynthesis of distal fibula fractures with biodegradable devices.

BACKGROUND: This study compared fixation with a titanium one-third tubular plate and one lag-screw vs. fixation with biodegradable plates with one lag-screw applied with two different plate-screw patterns. MATERIALS AND METHODS: Ten pairs of fibulas were osteotomied, plated (titanium plate with one lag screw vs. absorbable 2/8 plate-screws crossing vs. 0/8 plate-screws crossing the osteotomy gap). and tested in torsion and bending to obtain stiffness and neutral-zone (NZ) data. Tests were performed using 5 load cycles. No load to failure was performed. Biodegradation was simulated by 6 week immersion in phosphate-buffered saline after which the testing protocol was repeated. The specimens were then loaded with 100 N in bending. RESULTS: Post-implantation, there were no significant differences, in torsion and bending, regarding the NZ or the stiffness, between the 2/8 biodegradable plate and the titanium plate. The 0/8 pattern performed significantly less well in terms of stiffness and NZ in the initial torsion test, and significantly less well in terms of stiffness in the initial bending test. After 6 weeks' immersion, all biodegradable constructs showed a significantly larger NZ and significantly reduced bending and torsional stiffness. When loaded with 100 N, four of the six 0/8 osteosyntheses failed. There were no significant differences between the 2/8 pattern and the titanium plates. CONCLUSION: In a model of a Weber-B fracture, the use of a 2/8 biodegradable plate construct initially did not differ statistically to that obtained with a one-third tubular titanium plate. After immersion the 2/8 construct withstood some physiological load. CLINICAL RELEVANCE: For the fixation of ankle fractures with a biodegradable plate of the type employed in this study, the use of fracture-gap-crossing screws is recommended.

Microcephaly, short stature, and limb abnormality disorder due to novel autosomal biallelic DONSON mutations in two German siblings.

Recently, variants in DONSON have been reported to cause different disorders of the microcephalic primordial dwarfism spectrum. Using whole-exome sequencing, we identified two novel, compound heterozygous DONSON variants in a pair of siblings, one of whom was previously diagnosed with Fanconi anemia. This occurred because the present cases exhibited clinical findings in addition to those of the microcephalic primordial dwarfism disorder, including severe limb malformations. These findings suggest that the DONSON and Fanconi anemia proteins could have supplementary roles in developmental processes as they have in the maintenance of genomic integrity, resulting in related disease phenotypes.

Comparison of two intramedullary nails for tibiotalocalcaneal fusion: anatomic and radiographic considerations.

BACKGROUND: Retrograde intramedullary nailing is an established procedure for tibiotalocalcaneal arthrodesis. This study was conducted to see whether, and if so to what extent, nail design modifications would influence the risk to anatomic structures and the bony coverage of the nail base. METHODS: Six pairs of thawed fresh-frozen cadaver legs received two different intramedullary nails (N1: straight nail, lateral-medial tip locking; N2: valgus-curved nail, medial-lateral tip locking) under simulated operative conditions. The specimens were dissected; distances between the at-risk structures and the hardware were measured. The hindfoot axis and the volume of the intracalcaneal nail portion were determined with CT. RESULTS: At the plantar entry site, N2 was significantly farther from the flexor hallucis longus tendon (p=0.047), the medial plantar artery (p=0.026), and the lateral plantar nerve (p=0.026) than N1. The lateral-medial calcaneal locking screw of N1 damaged significantly more often the peroneus brevis tendon (p=0.03) than N2. The proximal tip-locking screw, N2, was significantly farther from the anterior tibial artery (p=0.075) and the deep (p=0.047) and superficial peroneal nerves (p=0.009) than N1; N1 was significantly farther from the great saphenous vein (p=0.075) than N2. The distal tip-locking screw, N1. damaged significantly more often the extensor digitorum longus (p=0.007), the anterior tibial artery(p = 0.04), and the deep and superficial peroneal nerves (p=0.03) than N2. CT did not show any significant changes in the hindfoot axis with either device; intracalcaneal nail volumes were similar. CONCLUSIONS: A curved nail can increase the distance to at-risk plantar structures. Medial-lateral nail-tip locking appears to have less risk to neurovascular structures. CLINICAL RELEVANCE: Safer retrograde intramedullary nailing for tibiotalocalcaneal fusion requires knowledge of the structures at risk and appropriate operative technique.

Systematic classification of uterine cervical elongation in patients with pelvic organ prolapse.

OBJECTIVE: To define and classify cervical elongation, to compare uterine measurements after prolapse hysterectomy with a non-prolapse control group, and to associate stage of prolapse and degree of cervical elongation. STUDY DESIGN: This was a single-centre retrospective case-control study conducted at the University Hospital, Urogynaecological Unit, with a certified urogynaecological surgeon. Data were collected from patients with and without pelvic organ prolapse (POP) who underwent laparoscopically assisted vaginal hysterectomy. Post-hysterectomy uterine cervical elongation was examined using the corpus/cervix ratio (CCR), calculated from measurements taken on photographs. Cervical elongation was classified as physiological (grade 0, CCR>1.5) grade I (CCR>1 and ≤1.5) grade II (CCR>0.5 and ≤1), and grade III (CCR≤0.5). RESULTS: Cervical elongation was detected in 288/295 (97.6%) patients in the prolapse group (grade I, 44/288 [15.2%]; grade II, 212 [73.6%]; grade III, 32 [11.1%]). Mean CCR was greater among those with stage II/III than among those with stage IV prolapse (1.0±0.4 vs. 0.8±0.2; p<0.001). Grades of cervical elongation and prolapse stages were associated (p<0.001). Grade I cervical elongation was detected in 26/69 (37.6%), grade II in 5/69, and grade III in 0/69 patients of the control group. Cervical elongation was found more often in the prolapse group compared to the control group (p<0.001). Mean total uterine length did not differ between the prolapse and control groups (8.0±1.6 vs. 8.2±1.3cm), but mean calculated cervical length was greater in the prolapse group than in the control group (4.4±1.1 vs. 3.1+0.8cm; p<0.001). CONCLUSIONS: Uterine cervical elongation is found in patients undergoing hysterectomy for pelvic organ prolapse. Cervical elongation grades and prolapse stages are correlated. Defining uterine cervical elongation based on corpus/cervix ratio with grades I-III could be a valuable basic tool for further research.

Origin of corpses received by the anatomical institute at the University of Jena during the Nazi regime.

During the Nazi regime (1933-1945), the anatomical institute at the University of Jena received 2,224 corpses, of which approximately 200 originated from executions. The available data clearly suggest that a large portion of these 200 executed persons must be considered victims of Nazi crimes. Approximately an equal number of bodies were delivered from state nursing homes and mental institutions in the state of Thuringia during the same time period. The available data suggest that it is highly likely that many of them were victims of decentralized "euthanasia" programs. The remains of many prisoners of nearby labor camps, mostly from Eastern Europe, are listed in the body register at the institute as well. A group of anatomists and historians has investigated the institute's association with Nazi crimes. Apart from documenting the association, the aim of the investigation is to clarify the whereabouts of the corpses. In particular, it must be ascertained that none of the specimens publicly displayed in the anatomical collection of the Friedrich Schiller University originated in the context of Nazi crimes.

Influence of angulation on metacarpal bone mineral density measurements using digital X-ray radiogrammetry.

OBJECTIVE: Digital X-ray radiogrammetry (DXR) is a computer-assisted technique used to quantify cortical bone density of the metacarpals. The influence of metacarpal bone rotation and type of cast material on bone mineral density (BMD) measurements using the DXR technique was tested. METHODS: The bone mineral density of the hand was measured by DXR, and rotation error (DXR-RE) as coefficients of variation were calculated, to verify reliability and reproducibility of this radiogeometric technique to assess in particular minor disease-related changes in the metacarpal bone mass. The reproducibility of the DXR measurements was also investigated using different cast materials (mull, elastic, and plastic). RESULTS: There were no significant changes in absolute values of DXR-BMD observed between 0 to [Formula: see text] angulation. The relative DXR-RE ranged between 0 % (degree 1) and 0.70 % (degrees 15 and 19) for DXR-BMD. Regarding the different cast materials, DXR-BMD revealed a coefficient of variation with 0.41 % (mull cast) and 0.21 % (elastic cast). For the plastic cast, the DXR technique was not able to perform an analysis of DXR-BMD. CONCLUSION: The study revealed no significant influence of metacarpal rotation on the measurements of metacarpal bone mineral density as estimated by DXR. DXR measurements are not optimal when cast material is used. DXR can accurately quantify periarticular cortical bone mass. This is significant especially for rheumatoid arthritis and related conditions where X-ray imaging of arthritic hands with varying degrees of deformity is performed.

Anatomical evaluation of different approaches for tibiotalocalcaneal arthrodesis.

BACKGROUND: The transfibular approach is commonly used for tibiotalocalcaneal arthrodesis. However, the medial and the posterolateral approaches are available as alternatives. The present study was performed to assess the effects of the 3 approaches on the neurovascular structures encountered and to quantify the extent of cartilage in the different joint compartments that could be surgically debrided. METHODS: This cadaver study was performed in 6 pairs of formalin-fixed legs (mean donor age: 80 years; 4 females, 2 males). For each approach, 4 specimens were selected. The neurovascular structures at risk and the debrided portions of the articular cartilage were compared. RESULTS: Arterial structures were least compromised by the transfibular approach. The posterolateral approach was particularly likely to damage the lateral malleolar branches of the peroneal artery. Venous structures were at risk mainly from the medial approach, which was also the most risk-bearing of the 3 approaches in terms of nerve damage. The proportions of cartilage-debrided joint surfaces of the tibia in the ankle joint, and of the talus and the calcaneus in the subtalar joint, did not differ notably. The proportions of debrided surfaces of the talus in the ankle joint differed notably among the 3 approaches. CONCLUSIONS: The medial approach could be a valid alternative to the lateral transfibular approach for tibiotalocalcaneal arthrodesis. Care should be taken, however, to prevent damage to the saphenous nerve and other neurological structures. CLINICAL RELEVANCE: Access morbidity and feasibility of adequate cartilage debridement are relevant to the clinical outcome of hindfoot arthrodesis.

Functional differentiation of the human lumbar perivertebral musculature revisited by means of muscle fibre type composition.

Human back muscles have been classified as local stabilizers, global stabilizers and global mobilizers. This concept is supported by the distribution of slow and fast muscle fibres in quadrupedal mammals, but has not been evaluated for humans because detailed information on the fibre type composition of their perivertebral musculature is rare. Moreover, such information is derived from spot samples, which are assumed to be representative for the respective muscle. In accordance with the proposed classification, numerous studies in animals indicate great differences in the fibre distribution within and among the muscles due to fibre type regionalization. The aims of this study were to (1) qualitatively explore the applicability of the proposed functional classification for human back muscles by studying their fibre type composition and (2) evaluate the representativeness of spot sampling techniques. For this, the fibre type distribution of the whole lumbar perivertebral musculature of two male cadavers was investigated three-dimensionally using immunohistochemistry. Despite great local variations (e.g., among fascicles), all muscles were composed of about 50% slow and 50% fast fibres. Thus, contradicting the concepts of lumbar muscle function, no functional differentiation of the muscles was observed in our study of the muscle contractile properties. The great similarity in fibre composition among the muscles equips each muscle equally well for a broad range of tasks and therefore has the potential to allow for great functional versatility of the human back musculature. Spot samples do not prove to be representative for the whole muscle. The great intraspecific variability observed previously in single-spot samples is potentially misleading.