Shortening effect influence of Distal Minimally Invasive Metatarsal Osteotomy in primary metatarsalgia.

PURPOSE: In primary metatarsalgia, Distal Minimally invasive Metatarsal Osteotomy (DMMO) achieves a correct load distribution which is a factor in pain relief, but contrary to the elevation of the metatarsal head, shortening the metatarsal length has no influence on plantar-loading parameters, while the increased metatarsal length is a factor in the development of metatarsalgia. Thus, we hypothesized that metatarsalgia could be partly related to a functional imbalance between bone structure and soft tissues and pain relief after DMMO results from soft tissue relaxation. METHODS: Many authors have highlighted the correlation between joint pressure and periarticular soft tissue tension. To test our hypothesis, we measured intra-operatively the MTPJ pressure of 19 patients suffering from primary metatarsalgia, before and after DMMO. This pressure is being analyzed as a reflection of joint decompression and forefoot soft tissue release. Many authors have highlighted the correlation between joint pressure and periarticular soft tissue tension. RESULTS: Lower metatarsals presenting metatarsalgia show a significantly lower MTPJ pressure compared to asymptomatic rays, and DMMO induces a significant increase of MTPJ pressure. CONCLUSION: Those variations reflect the functional imbalance between bone structure and soft tissue in primary metatarsalgia. The biomechanical rationale of the shortening effect of DMMO could therefore be explained by the release of forefoot soft tissue, which could take part in the pain relief by restoring this balance.

Correlation between first tarsometatarsal joint mobility and hallux valgus severity.

PURPOSE: The mobility of the first tarsometatarsal (TMT1) is said to be correlated to the severity of hallux valgus determined using both clinical and radiographic criteria. The sagittal mobility of the TMT1 joint can be evaluated objectively using a new ultrasound test, which quantifies it in the form of a unitless value (ratio of two measurements). The objective of this study was to describe the relationship between TMT1 mobility on an ultrasound test and hallux valgus severity. Hypothesis TMT1 joint mobility increases with hallux valgus severity. PATIENTS AND METHODS: Forty-nine feet were included that were being treated for isolated hallux valgus and had no evidence of TMT1 hypermobility based on the dorsal drawer test. For each foot, the presence and intensity of load transfer (LT), the intermetatarsal angle (IMA), and the hallux valgus angle (HVA) were determined. Lastly, TMT1 mobility was evaluated with the ultrasound test. RESULTS: Clinically, no LT was present in 20 feet; it was present only under M2 in 20 feet and reached at least M3 in the other nine feet. The mean IMA on radiographs was 14.6° and the mean HVA was 34.5°. The value of the ultrasound test was significantly different between the three groups of clinical hallux valgus severity: 1.17 with no LT, 1.31 with isolated M2 LT, and 1.72 when LT was at least at M3. Furthermore, this value was correlated with the IMA but not the HVA. DISCUSSION: This study revealed a relationship between increased TMT1 mobility and hallux valgus severity based on clinical (LT) and radiographic (IMA) criteria. Thus, our working hypothesis is confirmed. However, there was no correlation between TMT1 mobility and HVA suggesting that this angle is less relevant for determining the severity of the condition. This is consistent with the classical pathophysiological concept of metatarsus primus varus where the hallux valgus originates in a metatarsus varus in the tarsometatarsal area. CONCLUSION: The severity of hallux valgus is correlated with increased mobility of the TMT1 joint, which appears to have a causal role in this condition.

Increased performance in juvenile baboons is consistent with ontogenetic changes in morphology.

OBJECTIVES: In many primates, the greater proportion of climbing and suspensory behaviors in the juvenile repertoire likely necessitates good grasping capacities. Here, we tested whether very young individuals show near-maximal levels of grasping strength, and whether such an early onset of grasping performance could be explained by ontogenetic variability in the morphology of the limbs in baboons. MATERIAL AND METHODS: We quantified a performance trait, hand pull strength, at the juvenile and adult stages in a cross-sectional sample of 15 olive baboons (Papio anubis). We also quantified bone dimensions (i.e., lengths, widths, and heights) of the fore- (n = 25) and hind limb (n = 21) elements based on osteological collections covering the whole development of olive baboons. RESULTS: One-year old individuals demonstrated very high pull strengths (i.e., 200% of the adult performance, relative to body mass), that are consistent with relatively wider phalanges and digit joints in juveniles. The mature proportions and shape of the forelimb elements appeared only at full adulthood (i.e., ≥4.5 years), whereas the mature hind limb proportions and shape were observed much earlier during development. DISCUSSION: These changes in limb performance and morphology across ontogeny may be explained with regard to behavioral transitions that olive baboons experience during their development. Our findings highlight the effect of infant clinging to mother, an often-neglected feature when discussing the origins of grasping in primates. The differences in growth patterns, we found between the forelimb and the hind limb further illustrate their different functional roles, having likely evolved under different ecological pressures (manipulation and locomotion, respectively).

Post-operative hallux varus: a review of treatment methods.

PURPOSE: Hallux varus is a classical complication of hallux valgus surgery with a medium rate of 6%. MATERIAL AND METHODS: Methods of treatment are MTP1 fusion or conservative joint operations. Hallux varus results from imbalance between excessive medial capsule retraction or tensioning and excessive lateral laxity or soft-tissue release but also and mainly from an over displacement of the first metatarsal which reduces the intermetatarsal angle and thus leads to medial displacement of the great toe. A majority are well tolerated, but few need to be re-operated upon. RESULTS: Factors guiding choice are mainly range of motion and reducibility of the first metatarsophalangeal joint and tendon balance. Joint sparing could be decided for a mobile and well balancesd MTP1 with two options, soft-tissue repairing such as tendon and ligament transfer and reverse osteotomies. The choice depends mainly on the radiological features as an unduly closed intermetarsal angle which leads to a reverse scarf or chevron osteotomy whatever previous surgery was or was not with an osteotomy. CONCLUSION: Conservative treatment is tricky, and MTP1 fusion is still a reliable procedure which can be used widely.

Biomechanical study comparing the energy cost of human bipedalism versus zenkutsu-dachi stepping of a karateka.

Traditional stepping in the zenkutsu-dachi stance of the Shotokan style of karate is very physically demanding. It requires considerably more effort than what is expended during conventional human bipedalism. We performed a biomechanical study to analyze and compare these two types of gaits when performed by a highly experienced karateka. The study involved a three-dimensional motion analysis system (digital cameras and optical reflectors) and a force platform to analyze the ground reaction forces in all three planes. The study had both kinematic and kinetic components. We found that zenkutsu-dachi stepping is much more costly from an energetics point of view because the properties of the biarticular muscles are not used, the muscular moments of force are higher, and the body's potential energy is not converted into kinetic energy, contrary to the more economical model of human bipedalism that involves an inverted pendulum pattern.

Minimally invasive and percutaneous surgery of the forefoot current techniques in 2018.

Minimally invasive and percutaneous techniques used to repair deformities of the forefoot have considerably developed recently. Like standard osteotomies, these techniques must take advantage of the mechanical advances made in the restoration of the foot's architecture. Instead of an endpoint, these techniques represent an additional tool implemented towards a rapid functional, post-operative recovery. This review describes the power of this surgery, details its techniques and lists its indications. We also report our own experience and review the recent literature.

Minimally invasive surgery and percutaneous surgery of the hindfoot and midfoot.

Minimally invasive surgery (MIS) and percutaneous (PC) surgery recently spread as a new technique in operative forefoot correction, and by extension in hindfoot and midfoot. Numerous procedures were described, and a race for MIS and PC has started. However, performing surgery with small incisions should not be an end in itself. Biomechanical and anatomical concerns must be taken into account and shall not be sacrificed for cosmetic reasons. For the most common hindfoot and midfoot pathologies, we discuss what we consider the surgical necessities and then describe the MIS and/or PC procedure we choose, according to these fundamentals.

Postoperative Hallux Varus Treatment by Reverse Scarf Osteotomy.

BACKGROUND: Postoperative hallux varus is often accompanied by an abnormal decrease in the first-second (M1M2) intermetatarsal angle, which we have sought to correct by a reverse scarf-type osteotomy. METHODS: A series of 36 hallux varus operated on by reverse scarf osteotomy, including 14 with prior osteotomies, was reviewed with an average follow-up of 56 months. The measurements were clinical: American Orthopaedic Foot & Ankle Society (AOFAS) score, visual analog scale (VAS) pain score, subjective satisfaction index, joint mobility, and radiologic angles: M1M2 and first metatarsophalangeal angle. RESULTS: The M1M2 angle increased on average from 3 to 8 degrees whereas the average M1P1 angle of varus went from -21 to +9 degrees, including 2 patients who had a reoccurring valgus of 20 degrees. The median AOFAS score increased from 47 to 79, the VAS from 6.7 to 2.3, joint mobility lost an average of 9 degrees, and all those operated on were satisfied with the result. All operated bones healed without secondary displacement. DISCUSSION: The reverse scarf osteotomy is capable of correcting the intermetatarsal angle and at the same time correcting the postoperative hallux varus. Functional scores generally improved, including in patients with a reoccurring valgus and those with reduced mobility. CONCLUSION: The reverse scarf osteotomy can be performed to treat postoperative hallux varus with a mild intermetatarsal angle with reasonable clinical and radiologic results. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Reliability of a new dynamic ultrasound test for quantifying first-ray mobility.

BACKGROUND: First-ray hypermobility (FRHM) is a documented abnormality whose pathogenic role is controversial. FRHM has been suggested to participate in many common disorders such as paediatric hallux valgus and recurrence after hallux valgus surgery. The controversy is due to lack of functional data on the first tarso-metatarsal joint (TMT1) in real-life situations, to its major anatomical variability, and to the absence of simple investigation methods. The objective of this study was to assess the feasibility and the inter- and intra-observer reproducibility of a new dynamic ultrasound test that quantifies TMT1 mobility and is simple to use provided a good-quality ultrasound machine is available. HYPOTHESIS: The new ultrasound TMT1 mobility test is reproducible. MATERIAL AND METHODS: The 32 feet of 16 consecutive patients whose first ray was considered normal were included. Ultrasonography was performed at rest and during a stress test consisting in causing TMT1 gaping by applying a distal dorsal drawer movement to the first metatarsal. The two plantar bony prominences on either side of the TMT1 were identified, and the distance between them was measured at rest and during the stress test. The stress/rest ratio was computed. Each foot was tested twice by two different examiners, for a total of 128 tests. RESULTS: Mean TMT1 gaping distance was 1.38mm (range, 1.01-2.02mm) at rest and 1.67mm (range, 1.12-2.95mm). The mean stress/rest ratio was 1.21 (range, 1.02-1.62). Both inter- and intra-observer reliability was strong for all measured parameters. DISCUSSION: A simple and reproducible ultrasound test for measuring TMT1 mobility is described for the first time. The good reproducibility confirms the working hypothesis. This preliminary study was designed to validate the new test. The measured values need to be assessed in various disorders including FRHM, for which the test was designed. Should the results prove conclusive, the TMT1 gaping test may become a pivotal diagnostic tool. LEVEL OF EVIDENCE: IV, diagnostic study.

Effects of gastrocnemius tightness on forefoot during gait.

The gastrocnemius is the main muscle of the posterior compartment of the leg. As a biarticular muscle it has specific biomechanical propertiess. This article discusses these properties combining the major biomechanical topics of anatomy, dynamics, kinetics, and electromyography. This muscle is remarkable in that it has very low energy consumption and very high mechanical efficacy. In addition to the biomechanical features, the consequences of its tightness are discussed. The dysfunction also appears in all the biomechanical topics and clarifies the reasons of the location of symptoms in the midfoot and on the plantar aspect of the forefoot.