Overview of Metatarsalgia.

Metatarsalgia can be viewed as more of a symptom rather than a distinct diagnosis. Timing of forefoot pain during the gait cycle and evaluation of whether the pain is from anatomic abnormalities, indirect overloading, or iatrogenic causes can suggest a specific metatarsalgia etiology. A thorough physical examination of the lower extremity, especially evaluation of the plantar foot, and weight-bearing radiographs are critical for diagnosis and treatment. Nonoperative treatment consists of physical therapy, orthotics, shoe wear modification, and injections. If conservative treatment fails, surgical options may be considered. [Orthopedics. 2019; 42(1):e138-e143.].

The relationship between foot posture index, ankle equinus, body mass index and intermetatarsal neuroma.

BACKGROUND: The main purpose of this study was to investigate the presence of an association between intermetatarsal neuroma and foot type, as measured by the Foot Posture Index. The study also examined whether there was a relationship between foot type and the interspace affected with intermetatarsal neuroma, and whether ankle equinus or body mass index had an effect. METHODS: In total, 100 participants were recruited from The University of Western Australia's Podiatry Clinic, 68 of whom were diagnosed with inter-metatarsal neuroma from 2009 to 2015. There were 32 control participants recruited from 2014 to 2015. The age of subjects was recorded, as were weight and height, which were used to calculate body mass index. The foot posture index and ankle dorsiflexion were measured using standard technique. Independent t-tests and Kruskal-Wallis tests were used to compare differences in foot posture index, body mass index and ankle dorsiflexion between the inter-metatarsal neuroma and control groups. Multivariable logistic regression was also used to model relationships for outcome. RESULTS: The 68 intermetatarsal neuroma subjects had a mean age of 52 years (range 20 to 74 years) and comprised of 56 females and 12 males. The 32 control subjects had a mean age of 49 years (range 24 to 67 years) with 26 females and six males. There were no significant differences between the control and the intermetatarsal neuroma groups with respect to the mean foot posture index scores of the left and right foot (p = 0.21 and 0.87, respectively). Additionally no significant differences were detected between the affected intermetatarsal neuroma interspace and foot posture index (p = 0.27 and 0.47, respectively). There was no significant difference in mean body mass index between the intermetatarsal neuroma (26.9 ± 5.7) and control groups (26.5 ± 4.1) (p = 0.72). There was, however, a significant difference in mean ankle dorsiflexion between the intermetatarsal neuroma and control groups (p < 0.001 for both feet). Logistic regression models, adjusted for age, sex, foot posture index and body mass index estimated that the odds of having an intermetatarsal neuroma in the right foot increased by 61% (OR 1.61; 95% CI 1.32-1.96) with each one degree reduction of ankle dorsiflexion, and in the left foot by 43% (OR 1.43; 95% CI 1.22-1.69). CONCLUSION: No relationships were found between foot posture index and body mass index with intermetatarsal neuroma, or between foot posture index and the interspaces affected. However, a strong association was demonstrated between the presence of intermetatarsal neuroma and a restriction of ankle dorsiflexion.

Is there still a place for Achilles tendon lengthening?

Patients with diabetes and ankle equinus are at particularly high risk for forefoot ulceration because of the development of high forefoot pressures. Stiffness in the triceps surae muscles and tendons are thought to be largely responsible for equinus in patients with diabetes and underpins the surgical rationale for Achilles tendon lengthening (ATL) procedures to alleviate this deformity and reduce ulcer risk. The established/traditional surgical approach is the triple hemisection along the length of the Achilles tendon. Although the percutaneous approach has been successful in achieving increases in ankle dorsiflexion >30°, the tendon rupture risk has led to some surgeons looking at alternative approaches. The gastrocnemius aponeurosis may be considered as an alternative because of the Achilles tendon's poor blood supply. ATL procedures are a balance between achieving adequate tendon lengthening and minimizing tendon rupture risk during or after surgery. After ATL surgery, the first 7 days should involve reduced loading and protected range of motion to avoid rupture, after which gradual reintroduction to loading should be encouraged to increase tendon strength. In summary, there is a moderate level of evidence to support surgical intervention for ankle joint equinus in patients with diabetes and forefoot ulceration that is non-responsive to other conservative treatments. Areas of caution for ATL procedures include the risk for overcorrection, tendon rupture and the tendon's poor blood supply. Further prospective randomized control trials are required to confirm the benefits of ATL procedures over conservative care and the most optimal anatomical sites for surgical intervention.

Comparison of Efficacy and Side Effects of Oral Baclofen Versus Tizanidine Therapy with Adjuvant Botulinum Toxin Type A in Children With Cerebral Palsy and Spastic Equinus Foot Deformity.

This retrospective study aimed to compare the therapeutic response, including side effects, for oral baclofen versus oral tizanidine therapy with adjuvant botulinum toxin type A in a group of 64 pediatric patients diagnosed with static encephalopathy and spastic equinus foot deformity. Following botulinum toxin A treatment, clinical improvement led to the gradual reduction of baclofen or tizanidine dosing to one-third of the former dose. Gross Motor Functional Measure and Caregiver Health Questionnaire scores were markedly elevated post-botulinum toxin A treatment, with scores for the tizanidine (Gross Motor Functional Measure: 74.45 ± 3.72; Caregiver Health Questionnaire: 72.43 ± 4.29) group significantly higher than for the baclofen group (Gross Motor Functional Measure: 68.23 ± 2.66; Caregiver Health Questionnaire: 67.53 ± 2.67, P < .001). These findings suggest that the combined use of botulinum toxin A and a low dose of tizanidine in treating children with cerebral palsy appears to be more effective and has fewer side effects versus baclofen with adjuvant botulinum toxin A.

Mid-term Results of Intramuscular Lengthening of Gastrocnemius and/or Soleus to Correct Equinus Deformity in Flatfoot.

BACKGROUND: Intramuscular lengthening of the gastrocnemius and/or soleus (Baumann procedure) is widely used in patients who have cerebral palsy, with several advantages over other lengthening techniques. Tightness of the gastrocnemius or gastrocnemius-soleus complex has been confirmed to be related to flatfoot deformity. The purpose of this study was to evaluate the mid-term results of the Baumann procedure as a part of the treatment of flatfoot with equinus deformity. METHODS: We reviewed 35 pediatric and adult patients (43 feet) with flatfoot who underwent the Baumann procedure for the concomitant equinus deformity. The mean duration of follow-up was 39.4 months. Preoperative and follow-up evaluations included the maximal angle of dorsiflexion of the ankle with the knee fully extended and with the knee flexed to 90 degrees, the American Orthopaedic Foot & Ankle Society ankle-hindfoot (AOFAS-AH) scores, and postoperative complications. RESULTS: Preoperatively, the mean angle of passive ankle dorsiflexion with the knee extended was -4.7 ± 2.7 degrees and that with the knee flexed was 2.3 ± 2.5 degrees. At the final follow-up, both values improved significantly by a mean of 13.6 degrees (P < .001) and 9.7 degrees (P < .001), respectively. The average AOFAS-AH scores improved from 56.8 points preoperatively to 72.1 at the final follow-up. Recurrence of equinus was observed in 3 patients (4 feet). There were no cases of overcorrection, neurovascular injury, or healing problems. CONCLUSIONS: Our results indicate that the Baumann procedure can effectively and sequentially correct the tightness of the gastrocnemius or the gastrocnemius-soleus complex in patients with flatfoot deformity, without obvious postoperative complications. LEVEL OF EVIDENCE: Level IV, retrospective case series.

The effect of gastrocnemius tightness on the pathogenesis of juvenile hallux valgus: a preliminary study.

Hallux valgus is the most common foot disorder associated with gastrocnemius tightness, and there is a particularly strong association with juvenile hallux valgus. This article describes an oblique windlass mechanism that can be a causative or a contributory factor in the pathogenesis of juvenile hallux valgus. This article presents a study of 108 patients who underwent a proximal gastrocnemius release and hallux valgus correction using a scarf osteotomy. We believe that assessment of gastrocnemius tightness in juvenile hallux valgus is important and that gastrocnemius lengthening should be routinely considered as part of the operative strategy.

Effects of a dynamic-ankle-foot orthosis (Liberté®) on kinematics and electromyographic activity during gait in hemiplegic patients with spastic foot equinus.

BACKGROUND: A dynamic-ankle-foot orthosis has recently emerged and consists of an elastic band allowing the variation of stiffness degree and adjusts dorsiflexion assistance in swing. The aim of this study was to quantify the biomechanical adaptations induced by this orthosis during gait in hemiplegic patients. METHODS: Twelve hemiplegic patients performed two gait analyses (without and with the ankle-foot orthosis). Spatiotemporal, kinematic, kinetic and electromyographic gait parameters were quantified using an instrumented gait analysis system during the stance and swing phases. RESULTS: During swing, peak ankle dorsiflexion was greater with the orthosis and associated with a decrease of pelvic obliquity angle. In stance, peak ankle plantarflexion and dorsiflexion were greater with the orthosis and associated with an increase of ankle angle at heel strike and toe-off. Electromyographic activities of both the tibialis anterior and the medial gastrocnemius were greater with the orthosis. CONCLUSIONS: This dynamic-ankle-foot orthosis improved gait in hemiplegic patients with spastic foot equinus. The spatiotemporal adaptations seem to be caused mainly by the increase of ankle dorsiflexion during stance and swing phases. The changes in electromyographic activity were related to an active dorsiflexion in stance and swing phases and an active plantarflexion in stance phase.

The association of equinus and primary genu recurvatum gait in cerebral palsy.

Primary genu recurvatum (GR) is less investigated and data presenting the prevalence among patients with bilateral spastic cerebral palsy (BSCP) is lacking in the literature. Equinus is mentioned as one of the main underlying factors in GR, but its influence on the severity and onset type of GR is mainly unanswered, yet. Hence, the purpose of this retrospective study was to assess the prevalence of GR in a large sample size in children with BSCP and to investigate sagittal plane kinematics to evaluate the influence of equinus on different GR types using data of three-dimensional gait analysis. GR was defined as a knee hyperextension of more than one standard deviation of an age matched control group during stance phase in either one or both of the limbs. Primary GR was defined as a GR without having previous surgery regarding the lower extremity, no selective dorsal rhizotomy and/or interventions like botulinum toxin injection, shock wave therapy or serial casting during the last 6 months in the patient history. In a retrospective study 463 patients with BSCP (GMFCS Level I-III) received three-dimensional gait analysis and were scanned for the presence of primary GR. Finally, 37 patients (23 males, 14 females) matched the determined inclusion criteria and were therefore included for further analysis in this study. Out of those patients seven walked with orthoses or a walker and were excluded from further statistical comparison: Kinematics of the lower limbs were compared between patients having severe (knee hyperextension>15°) and moderate (knee hyperextension 5-15°) GR and between patients showing an early (first half of stance phase) and a late (second half of stance phase) GR. Primary GR was present in 37 patients/52 limbs (prevalence 8.0/5.6%). Severe GR was associated with a decreased ankle dorsiflexion compared with moderate GR. Early GR showed an increased knee hyperextension compared to late GR. In conclusion GR is less frequent compared with crouch or stiff gait. Our findings support the importance of equinus as a major underlying factor in primary GR. In this context the influence of equinus seems to be more important in early GR.

Treatment of posttraumatic equinus deformity and concomitant soft tissue defects of the heel.

BACKGROUND: To evaluate the operative method and clinical outcome for the treatment of posttraumatic equinus deformity and concomitant soft tissue defect of the heel. METHODS: Between June 2006 and May 2010, seven cases of posttraumatic equinus deformity and concomitant unstable scar or ulcer of the heels were treated by using a hinged Ilizarov apparatus and reversed sural fasciocutaneous island flap transfer. Achilles tendon lengthening was also done in all patients. The average duration of follow-up was 21 months. The sizes of sural flaps were from 7 cm × 6 cm to 10 cm × 9 cm. Two weeks after the flap transfer, distraction of the Ilizarov fixator was initiated to gradually correct the equinus position of the foot. RESULTS: Results were evaluated by using the following criteria: (1) the degree of active dorsiflexion of the ankle, (2) the total active range of motion of the ankle, and (3) walking ability and flap durability. For active dorsiflexion of the ankle, the results were good in three patients and fair in four patients. For range of active motion of the ankle, the results were good in five patients and fair in two patients. For walking ability and flap durability, the results were good in six patients and fair in one patient. CONCLUSION: This study showed that posttraumatic equinus deformity accompanied by soft tissue defect of the heel can be treated effectively with Achilles tendon lengthening, reversed sural fasciocutaneous island flap transfer, and a hinged Ilizarov technique.

Flexible and rigid casting tape as a novel approach to offloading diabetic foot ulcers.

Offloading diabetic ulceration is a key component to the success in healing ulcers on the plantar aspect of the foot. New advances in offloading techniques allow for differing approaches in sometimes complex diabetic foot pathologies with associated ulceration. This case study looks at the use of flexible and rigid casting technique as part of the treatment in offloading plantar foot ulceration.

Split anterior tibial tendon transfer for varus equinus spastic foot deformity Initial clinical findings correlate with functional results: A series of 132 operated feet.

Spastic equinovarus foot deformity commonly occurs after stroke or head trauma. Management by split anterior tibial tendon transfer to the lateral border of the foot was chosen by the authors. The purpose of that work was to assess the reliability of this method to improve patient's functional autonomy and investigate the relationship between the initial clinical examination findings and the quality of the functional results. 84 feet, operated in 82 patients out of 130, of mean age 46 years, were reviewed at a mean follow-up of 65 months. Very few complications were observed. Toe deformities remain a commonly associated problem. 80 patients were able to walk barefoot, 74 reported an increase in their walking distance, and 73 could regularly wear normal shoes. There is a strong relationship (p<0.001) between the preservation of deep foot sensitivity and the level of functional autonomy.

Casting, taping or stretching after botulinum toxin type A for spastic equinus foot: a single-blind randomized trial on adult stroke patients.

OBJECTIVE: To investigate the effect of different adjunctive treatments after botulinum toxin type A. DESIGN: Single-blind, randomized trial, with three-month follow-up. SETTING: Secondary rehabilitative care. SUBJECTS: Convenience sample of 69 chronic hemiplegic adult patients with spastic equinus foot. INTERVENTIONS: Following botulinum toxin type A injection at the plantar flexors, patients were randomly assigned to three groups and treated with either taping, casting or stretching for one week, and with stretching and gait training for the next week. OUTCOME MEASURES: Modified Ashworth Scale at plantar flexors, passive range of motion at the ankle, six-minute walking test, 10-metre walking test, Functional Ambulation Categories, ankle dorsiflexor strength were evaluated before treatment (t(0)) at 20 days (t(1)) and 90 days (t(2)) after treatment. RESULTS: At t(1) only the taping and casting groups showed significant improvements in Modified Ashworth Scale, six-minute walking test, 10-metre walking test and passive range of motion (P < 0.02). At t(2), while the results were maintained in the casting group, only six-minute walking test and Modified Ashworth Scale were still significantly improved in the taping group. Ankle dorsiflexor strength and Functional Ambulation Categories did not change in any of the groups at any time. At t(2) the casting group performed better than the taping and stretching groups at Modified Ashworth Scale and passive range of motion, and better than the stretching group at six-minute walking test (P < 0.02). CONCLUSIONS: Combining botulinum toxin type A to the ankle plantar flexors with casting or taping gives better and longer lasting results than with stretching alone.

Equinus foot classification in cerebral palsy: an agreement study between clinical and gait analysis assessment.

BACKGROUND: Excessive ankle plantar flexion (equinus foot) is a common problem in cerebral palsy (CP) and several treatment options can be considered depending on the equinus type. Few attempts have been made to classify different forms of equinus foot for specific treatment. AIM: This study is aimed at defining equinus foot types in CP patients according to the Ferrari classification, integrating clinical and instrumental assessments. The hypothesis is that clinical differentiation of equinus foot can be evidenced by recurrent anomalies identifiable through gait analysis (GA), which can make the assessment, usually based only on clinician semeiotics, more objective. DESIGN: Clinical and instrumental assessments were performed separately by a senior CP physiatrist and a senior GA physiatrist, the latter was blind to the clinical diagnosis of equinus type. SETTING: Outpatients POPULATION: Twenty patients, 16 diplegics and 4 hemiplegics (mean age 11 years, SD 4 years 11 months). METHODS: Clinical assessment by means of Modified Ashworth Scale, Gross Motor Function Measure (GMFM), Observational Gait Analysis (OGA), and measurement of lower limb muscle strength by dynamometer were used to classify the equinus type. Gait analysis assessed the kinematics and EMG of affected lower limbs. RESULTS: Ten different equinus types were identified. Since various forms of equinus can be present in the same patient, we were able to classify a total of 61 types of equinus in 36 feet. Substantial agreement was found between Clinical and Gait Analysis equinus assignment matched in 50 out of 61 types (Index of agreement with Fleiss' Kappa 79.3 % ). In some case only Gait Analysis was able to identify the equinus type, while in others it did not confirm clinical assignment. CONCLUSION: Gait analysis is able to distinguish different equinus types according to Ferrari classification, making the clinical decision less arbitrary. CLINICAL REHABILITATION IMPACT: Correct objective diagnosis of equinus foot in CP patients is of paramount importance when choosing suitable rehabilitative interventions.

Tetrafocal leg reconstruction using combined Ilizarov/TSF technique.

Treatment of segmental tibial bone defects after high-energy trauma or atrophic nonunion resection is challenging. In the last two decades, distraction osteogenesis Ilizarov bone transport has become a gold standard for the treatment of segmental tibial bone defects and lengthening in spite of the fact that frequent frame modifications and the need for sequential correction of deformities during bone transport are the main limitations of the device itself. The Taylor Spatial Frame applies the concept of the Stewart platform to the standard Ilizarov frame while applying the same principles of distraction osteogenesis postulated by Ilizarov. We report the case of a patient with two problems we could treat simultaneously: an ankle equinus contracture (a consequence of limb leg discrepancy) and infected tibial nonunion and soft-tissue damage complication after plating in a 41A3 type II Gustilo fracture of the left leg.

Neuronox versus BOTOX for spastic equinus gait in children with cerebral palsy: a randomized, double-blinded, controlled multicentre clinical trial.

AIM: The aim of this study was to evaluate the efficacy and safety of a newly manufactured botulinum toxin, Neuronox, compared with BOTOX for the treatment of the spastic equinus gait in children with cerebral palsy. METHOD: A total of 127 children with cerebral palsy, aged 2 to 10 years, who presented at three university hospitals with spastic equinus gait were assessed for eligibility to participate in this double-blinded, randomized, controlled trial. Of the 119 eligible participants (mean age 4.33 y; SD 2.07; 76 males and 43 females; 79 with diplegia and 40 with hemiplegia), 57 were classified as Gross Motor Function Classification System level I, 29 as level II, and 33 as level III. Participants were randomly assigned to receive an injection of Neuronox (n=60) or BOTOX (n=59) to the calf muscles at a dose of 4U/kg for those with hemiplegia and 6U/kg for those with diplegia. Assessments were performed at baseline (V1) and at 4 (V2), 12 (V3), and 24 (V4) weeks after the intervention. The primary outcome measure was response rate at V3, with a positive response being defined as at least a 2-point increase in the Physicians' Rating Scale (PRS) score. The non-inferiority margin was set as -20% for the difference in the response rate. The secondary outcome measures included PRS score, passive range of motion (PROM) of the ankle and knee, and Gross Motor Function Measure 88 (GMFM-88). Any adverse events were investigated for safety implications. RESULTS: The response rate of the Neuronox group at V3 was not inferior to that of the BOTOX group (90% lower limit=-11.58%). There were significant improvements in PRS, PROM of ankle dorsiflexion, and GMFM scores at V2, V3, and V4 in both groups. The changes in PRS score were not statistically different between the two groups in serial evaluation (p=0.96). PROM of the ankle dorsiflexion increased without any significant difference between the two groups, either overall (p=0.56) or at each visit (V2, p=0.32; V3, p=0.66; V4, p=0.90). The increase in GMFM score in serial measurements were not significantly different between the two groups (p=0.16), whereas it was larger in the BOTOX group than in the Neuronox group at V2 and V4 (p=0.03 and 0.05 respectively). The frequency of adverse events was not significantly different between the two groups (p=0.97), and drug-related complications of Neuronox treatment were not addressed. INTERPRETATION: The outcomes of Neuronox, based on PRS, proved to be as effective and safe as those of BOTOX for the treatment of spasticity in individuals with cerebral palsy.

Application of the Ilizarov technique to the correction of neurologic equinocavovarus foot deformity.

BACKGROUND: The treatment of rigid equinocavovarus foot deformities caused by neurologic disorders is often difficult and relapse is common. QUESTIONS/PURPOSES: We asked whether the Ilizarov technique could be used for correction of neurologic equinocavovarus foot deformities resulting in improved foot and ankle function and patient satisfaction. PATIENTS AND METHODS: The neurologic equinocavovarus foot deformities of 26 patients (mean age, 18.7 years; 29 feet) were treated using the Ilizarov technique. Nine feet were treated by distraction histiogenesis only with limited soft tissue release, whereas 20 feet needed additional osteotomy and/or tendon transfer/lengthening. Minimum followup was 12 months (mean, 72.9 months; range, 12-155 months). RESULTS: The mean time required for deformity correction was 27.1 days (range, 14-47 days) and the mean time for stabilization in the apparatus was 23.2 days (range, 7-53 days). A painless, stable, and plantigrade result was obtained by 22 patients (24 feet). Mild residual foot deformity was observed in the remaining five feet of four patients. Six patients (six feet) experienced postoperative complications. Three patients (four feet) experienced recurrence of the deformity requiring surgical correction. CONCLUSIONS: Ilizarov soft tissue distraction with or without callotasis of tarsal bone(s) allows a greater degree of correction of neurologic equinocavovarus foot deformities. However, to reduce the risk of recurrence after fixator removal, it may be necessary to overcorrect the deformity while in the fixator, to use nighttime splinting, and most importantly, to eliminate neuromuscular imbalance, if necessary, by combining arthrodesis with or without tendon transfer. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Does the treatment of spastic equinovarus deformity following stroke with botulinum toxin increase gait velocity? A systematic review and meta-analysis.

While botulinum toxin-A (BT-A) has been used to treat lower-limb focal spasticity successfully, its effect on characteristics of gait has not been well defined. The objective of this systematic review was to establish the treatment effect associated with the use of BT-A for equinovarus to improve gait velocity following stroke, using a meta-analytic technique. Relevant studies were identified through a literature search encompassing the years 1985 to November 2009. Studies were included if (i) the sample was composed of adult subjects recovering from either first or subsequent stroke, presenting with spastic equinovarus deformity of the ankle preventing full active dorsiflexion, and (ii) subjects who received BT-A were compared with subjects who had received a placebo, or (iii) in the absence of a placebo-controlled condition, subject had received BT-A and was assessed before and after treatment. A standardized mean difference (SMD) ± standard error and 95% confidence interval (CI) for gait velocity between the treatment and control group was calculated for each study, using Hedges's g, and the results pooled. Eight trials, five randomized controlled trials, and three single group intervention studies were included. Data representing 228 subjects were available for pooled analysis. Treatment with BT-A was associated with a small improvement in gait velocity (Hedge's g = 0.193 ± 0.081; 95% CI: 0.033 to 0.353, P < 0.018) representing an increase of 0.044 meters/s. The use of BT-A for lower-limb post-stroke equinovarus because of spasticity was associated with a small, but statistically significant increase in gait velocity.

Endoscopic gastrocnemius recession for treating equinus in pediatric patients.

UNLABELLED: Gastrocnemius recessions have been performed as open or endoscopic procedures. Most of the literature describes the outcomes of these procedures in children with specific neurologic limitations. We report an alternative approach to endoscopic gastrocnemius recessions in neurologically healthy pediatric and adolescent patients whose gastrocnemius equinus could not be corrected nonoperatively. We prospectively followed 23 patients (16 boys, seven girls) who underwent 40 procedures for equinus deformity (n = 22) or osteoarthritis (n = 1). All patients had been directly referred for surgical treatment because all previous nonoperative treatments (stretching, night splints, orthotics, nonsteroidal anti-inflammatory drugs, and physical therapy) had failed. The indications for surgery were patients age 18 years or younger experiencing symptomatic equinus unresponsive to nonoperative care. Pre- and postoperative ankle dorsiflexion were measured. The minimum followup for study inclusion was 1 year (mean, 2.9 years; range, 2-5.1 years). For every patient, dorsiflexion range of motion improved (mean, 15 degrees ; standard deviation, 4 degrees ). No patient had diminished nerve sensation postoperatively. This technique can be used to correct gastrocnemius equinus in otherwise healthy children who have not benefited from prior nonsurgical treatment. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.