Towards a comprehensive biomechanical assessment of the elderly combining in vivo data and in silico methods.

The aging process is commonly accompanied by a general or specific loss of muscle mass, force and/or function that inevitably impact on a person's quality of life. To date, various clinical tests and assessments are routinely performed to evaluate the biomechanical status of an individual, to support and inform the clinical management and decision-making process (e.g., to design a tailored rehabilitation program). However, these assessments (e.g., gait analysis or strength measures on a dynamometer) are typically conducted independently from one another or at different time points, providing clinicians with valuable yet fragmented information. We hereby describe a comprehensive protocol that combines both in vivo measurements (maximal voluntary isometric contraction test, superimposed neuromuscular electrical stimulation, electromyography, gait analysis, magnetic resonance imaging, and clinical measures) and in silico methods (musculoskeletal modeling and simulations) to enable the full characterization of an individual from the biomechanical standpoint. The protocol, which requires approximately 4 h and 30 min to be completed in all its parts, was tested on twenty healthy young participants and five elderlies, as a proof of concept. The implemented data processing and elaboration procedures allowing for the extraction of several biomechanical parameters (including muscle volumes and cross-sectional areas, muscle activation and co-contraction levels) are thoroughly described to enable replication. The main parameters extracted are reported as mean and standard deviation across the two populations, to highlight the potential of the proposed approach and show some preliminary findings (which were in agreement with previous literature).

Effects of MLS Laser on pain, function, and disability in chronic non-specific low back pain: A double-blind placebo randomized-controlled trial.

BACKGROUND: Among non-pharmacological interventions, Multiwave Locked System (MLS) Laser therapy has been used in patients with several musculoskeletal pathologies and in combination with other therapeutical interventions. The effects of sole MLS therapy on pain and function in patients with chronic non-specific low-back pain are unknown. OBJECTIVE: The objective of this study was to investigate the effects of MLS Laser therapy on pain, function, and disability in patients with chronic non-specific low back pain in comparison to a placebo treatment group. METHODS: Forty-five patients were randomized into two groups: the MLS Laser group and the Sham Laser group, undergoing 8 sessions of either a MLS Laser therapy or a Sham Laser therapy, respectively. At the beginning of the therapy (T0), at the end of the therapy (T1), and 1 month after the end of therapy (T2) patients were assessed for low back pain (by means of a VAS scale), function (by means of kinematic and electromyographic assessment of a forward bending movement) and self-reported disability (by means of the Roland-Morris and Oswestry Disability questionnaires). RESULTS: There was a significant reduction of pain and disability in both groups at T1 and T2 in comparison with T0. At T2 patients in the MLS group showed a significantly lower pain in comparison with patients in the Sham group (VAS = 2.2 ± 2 vs. 3.6 ± 2.4; p< 0.05). No differences between the two groups were found for function and disability. CONCLUSION: Both MLS Laser and Sham Laser therapies lead to a significant and comparable reduction in pain and disability in patients with chronic non-specific low back pain. However, one month after treatment, MLS Laser therapy has been found to be significantly more effective in reducing pain as compared to sham treatment.

Individuals With Chronic Ankle Instability Show Abnormalities in Maximal and Submaximal Isometric Strength of the Knee Extensor and Flexor Muscles.

BACKGROUND: It has been shown that chronic ankle instability (CAI) leads to abnormalities in neuromuscular control of more proximal joints than the ankle. Although strength of the hip and the ankle muscles has been largely investigated providing concordant results, limited evidence with contrasting results has been reported regarding knee extensor and flexor muscles. PURPOSE: To investigate maximal and submaximal isometric muscle strength in individuals with CAI. STUDY DESIGN: Controlled laboratory study. METHODS: Fifteen participants with unilateral CAI and 15 healthy matched controls were recruited. To quantify maximal strength, peak forces were recorded during a maximal isometric voluntary contraction of knee extensor and flexor muscles at 30° and 90° of knee flexion and normalized by the body weight of each participant. At both angles, submaximal isometric contractions at 20%, 50%, and 80% of the maximal voluntary isometric contraction were performed to analyze strength steadiness, in terms of coefficient of variation, and strength accuracy, in terms of absolute error. During all the assessments, knee extensor and flexor muscle activation was recorded by means of surface electromyography. RESULTS: Knee flexor maximal isometric strength was significantly lower in the injured limb of individuals with CAI in comparison with healthy controls at both 30° (0.15 ± 0.05 vs 0.20 ± 0.05; P < .05) and 90° (0.14 ± 0.04 vs 0.18 ± 0.05; P < .05). Knee extensor and flexor steadiness was significantly lower (higher coefficient of variation) in both the injured and the noninjured limbs of individuals with CAI in comparison with healthy individuals at 90° and at 30° for knee flexor steadiness of the injured limb. Knee extensor and flexor accuracy was lower (higher absolute error) in both the injured and noninjured limbs of individuals with CAI in comparison with healthy individuals, mainly at 30°, while at 90° it was lower only in the injured limb. No differences between the 2 groups were found for maximal isometric strength of knee extensor muscles, as well as for muscle activations. CONCLUSION: Individuals with CAI show abnormalities in maximal and submaximal isometric strength of knee flexor muscles, and submaximal strength of the knee extensor muscles. Further studies should deeply investigate mechanisms leading to these abnormalities. CLINICAL RELEVANCE: Rehabilitation interventions should consider abnormalities of neuromuscular control affecting joints more proximal than the ankle in individuals with CAI. REGISTRATION: NCT05273177 (ClinicalTrials.gov identifier).

Balance and Muscle Synergies During a Single-Limb Stance Task in Individuals With Chronic Ankle Instability.

The aim of this study was to investigate balance performance and muscle synergies during a Single-Limb Stance (SLS) task in individuals with Chronic Ankle Instability (CAI) and a group of healthy controls. Twenty individuals with CAI and twenty healthy controls were asked to perform a 30-second SLS task in Open-Eyes (OE) and Closed-Eyes (CE) conditions while standing on a force platform with the injured or the dominant limb, respectively. The activation of 13 muscles of the lower limb, hip, and back was recorded by means of surface electromyography. Balance performance was assessed by identifying the number and the duration of SLS epochs, and the Root-Mean-Square (RMS) in Antero-Posterior (AP) and Medio-Lateral (ML) directions of the body-weight normalized ground reaction forces. The optimal number of synergies, weight vectors, and activation coefficients were also analyzed. CAI group showed a higher number and a shorter duration of SLS epochs and augmented ground reaction force RMS in both AP and ML directions compared to controls. Both groups showed an increase in the RMS in AP and ML forces in CE compared to OE. Both groups showed 4 optimal synergies in CE, while controls showed 5 synergies in OE. CAI showed a significantly higher weight of knee flexor muscles in both OE and CE. In conclusion, muscle synergies analysis provided an in-depth knowledge of motor control mechanisms in CAI individuals. They showed worse balance performance, a lower number of muscle synergies in a CE condition and abnormal knee flexor muscle activation compared to healthy controls.

Acupuncture as an alternative or in addition to conventional treatment for chronic non-specific low back pain: A systematic review and meta-analysis.

Background: Conventional therapies (CTs), pharmacological (PH) and non-pharmacological (NPH), do not always achieve benefits in the treatment of chronic low back pain (CLBP). We assessed efficacy and safety of acupuncture for CLBP as alternative or addition to CT. Methods: We included randomised controlled trials (RCTs) comparing acupuncture alone or in combination with CT to CT. We searched Medline, Cochrane Library, Embase up to May 2022. We assessed risk of bias with the original Cochrane tool and GRADE certainty of evidence. Results were pooled through meta-analysis. Results: Ten RCTs (2122 participants) were included comparing acupuncture versus CT and 4 RCTs (374 participants) were comparing acupuncture plus CT to CT alone. In terms of comparing acupuncture with NPH or PH, no differences were found for pain and disability. Comparing acupuncture with PH and NPH combined, pain and disability were reduced (SMD=-0.50, 95% CI -0.62 to -0.37; SMD=-0.71, 95% CI -1.17 to -0.24). Comparing acupuncture plus NPH with NPH alone, pain and disability were reduced (SMD=-0.70, 95% CI -0.94 to -0.46; SMD=-0.95, 95% CI -1.36 to -0.54). Comparing acupuncture plus PH with PH alone, pain and disability were reduced (MD=-0.21, 95% CI -433.28 to -10.42; MD=-3.1, 95% CI -4.87 to -1.83). Comparing acupuncture plus combined treatment versus combined treatment alone, no differences were found in pain, while disability was reduced (MD=-3.40 95% CI -5.17 to -1.63). No studies assessed adverse event. Certainty of evidence ranged from moderate to very low. Conclusions: We are uncertain whether acupuncture is more effective and safer than CT. In the comparisons without estimates' imprecision, acupuncture showed promising results. Acupuncture could be an option based on patients' preferences.

Ultrasound-Guided Infiltrative Treatment Associated with Early Rehabilitation in Adhesive Capsulitis Developed in Post-COVID-19 Syndrome.

Background and Objectives: Post-COVID-19 syndrome is commonly used to describe signs and symptoms that continue or develop after acute COVID-19 for more than 12 weeks. The study aimed to evaluate a treatment strategy in patients with adhesive capsulitis (phase 1) developed in post-COVID-19 syndrome. Materials and Methods: The method used was an interventional pilot study in which 16 vaccinated patients presenting with the clinical and ultrasound features of adhesive capsulitis (phase 1) developed during post-COVID-19 syndrome were treated with infiltrative hydrodistension therapy under ultrasound guidance associated with early rehabilitation treatment. Results: Sixteen patients with post-COVID-19 syndrome treated with ultrasound-guided infiltration and early rehabilitation treatment showed an important improvement in active joint ROM after 10 weeks, especially in shoulder elevation and abduction movements. The VAS mean score before the treatment was 6.9 ± 1.66. After 10 weeks of treatment, the VAS score was 1 ± 0.63. Conclusions: The study demonstrated that the management of adhesive capsulitis (phase 1) developed in post-COVID-19 syndrome, as conducted by physiotherapists in a primary care setting using hydrodistension and a rehabilitation protocol, represented an effective treatment strategy.

Ultrasound Evaluation of Tendinopathy in Hemophiliac Patients for the Purpose of Rehabilitation Indications.

BACKGROUND: Hemophilia is a inherited bleeding disorder that is characterized by intra-articular bleeding (hemarthrosis). The aim of the study was to evaluate the state of the satellite tendons of the target joints in the patient with hemophilic arthropathy and propose rehabilitation treatment with eccentric exercises. METHODS: The tendons of the joints mainly affected by hemophilic arthropathy were evaluated by ultrasound. The ultrasound evaluation is associated with the use of evaluation clinical scales, such as the Hemophilia Joint Health Score (HJHS), the Functional Independence Score in Hemophilia (FISH), the Hemophilia Activity List (HAL), the DASH, the VISA-A, the VISA-P, and the VAS scale. RESULTS: In 20 patients with hemophilic arthropathy, the thickness of the tendons that were examined was normal. In six subjects with severe joint damage, echostructural alterations were present, and signs of hyperemia and neo-vascularization were detected on color Doppler, as well as the presence of intratendinous calcifications. CONCLUSIONS: The tendons of the target joints in patients with hemophilic arthropathy are compromised by the indirect biomechanical damage caused by the joint disease, and rehabilitation treatment with eccentric exercises can be considered safe and effective in improving the tenso-elastic properties of the tendons.

Psychological Well-Being, Self-Esteem, Quality of Life and Gender Differences as Determinants of Post-Traumatic Growth in Long-Term Knee Rotationplasty Survivors: A Cohort Study.

Rotationplasty (RP) is a special surgical technique for bone tumors of the lower limb and is the chosen procedure for children under 6 with bone sarcoma in the distal femur. Leg reconstruction results in an unusual aspect of the limb potentially giving life-long emotional outcomes, especially considering the young age of most RP patients. Although the high level of the quality of life of these patients has been previously reported, aspects related to long-term psychological well-being, self-esteem and life satisfaction, particularly regarding the gender, procreation and parenting, have never been explored. The aim of this study was to assess the general degree of psychological well-being of RP patients, with specific reference to gender, procreation and parenting. Twenty long-term RP survivors of high-grade bone sarcoma participated in the study. They were administered the following validated questionnaires: HADS for psychological well-being (degree of anxiety and depression), Temperament and Character Inventory (TCI), RSES for self-esteem, SF-36 for quality of life, SWLS extended to life satisfaction, and ABIS for body image integration. Data on education, marriage, employment and parenthood were gathered. All the scores obtained were very close to normal references. The only gender difference was found for the TCI Cooperativeness scale, which was higher in women than in men. A satisfactory psychological well-being in terms of both self-esteem and integration of the prosthetic joint limb into one's body image, with relatively limited amount of anxiety/depression, good quality of life, and good temperament and character traits, was found. No major gender differences were reported.

Suitability of the animated activity questionnaire for use as computer adaptive test: establishing the AAQ-CAT.

PURPOSE: The animated activity questionnaire (AAQ) is a computer-based measure of activity limitations. To answer a question, patients choose the animation of a person performing an activity that matches their own level of limitation. The AAQ has not yet been tested for suitability to be applied as computer-adaptive test (CAT). Thus, the objective of this study was to develop and evaluate an AAQ-based CAT to facilitate the application of the AAQ in daily clinical care. METHODS: Patients (n = 1408) with hip/knee osteoarthritis from Brazil, Denmark, France, The Netherlands, Norway, Spain, and the UK responded to all 17 AAQ items. Assumptions of item-response theory (IRT) modelling were investigated. To establish item parameters for the CAT, a graded response model was estimated. To evaluate the performance of post-hoc simulated AAQ-based CATs, precision, test length, and construct validity (correlations with well-established measures of activity limitations) were evaluated. RESULTS: Unidimensionality (CFI = 0.95), measurement invariance (R2-change < 2%), and IRT item fit (S-X2 p > .003) of the AAQ were supported. Performing simulated CATs, the mean test length was more than halved (≤ 8 items), while the range of precise measurement (standard error ≤ 0.3) was comparable to the full AAQ. The correlations between original AAQ scores and three AAQ-CAT versions were ≥ 0.95. Correlations of AAQ-CAT scores with patient-reported and performance measures of activity limitations were ≥ 0.60. CONCLUSION: The almost non-verbal AAQ-CAT is an innovative and efficient tool in patients with hip/knee osteoarthritis from various countries, measuring activity limitations with lower respondent burden, but similar precision and construct validity compared to the full AAQ.

Is mirror therapy associated with progressive muscle relaxation more effective than mirror therapy alone in reducing phantom limb pain in patients with lower limb amputation?

Mirror therapy is a widely used treatment for phantom limb pain (PLP) relief in patients with limb loss. Less common is progressive muscle relaxation (PMR), used mostly in other medical conditions (psychological, terminal cancer pain, etc). The purpose of this study is to evaluate the efficacy of a mirror therapy preceded by PMR intervention compared to mirror therapy preceded by unguided generic relaxation-mirror therapy in patients with lower limb amputation suffering from PLP. This pilot study was a single-blind, controlled, randomized trial. Thirty lower limb amputees suffering from PLP were recruited and randomly assigned to three groups respectively undergoing a PMR-mirror therapy rehabilitative intervention, generic relaxation-mirror therapy, and conventional physiotherapy (ConvPT). Selected items from Prosthesis Evaluation Questionnaire (PEQ) and the Brief Pain Inventory (BPI) were used to test the pain features at the beginning and 1 week after 3 weeks of intervention. A decrease of about 65% was found in the rate and duration of PLP at the PEQ in PMR-mirror therapy with respect to generic relaxation-mirror therapy (about 30%) and ConvPT (about 6%). A decrease of about 90% in intensity (worst and average) of PLP in PMR-mirror therapy when compared to generic relaxation-mirror therapy (about 45%) and ConvPT (about 20%) was found at the BPI. We preliminary concluded, albeit with limitations due to the small sample of patients, that mirror therapy can improve PLP when associated with PMR. Further studies are required to confirm that PMR could be an effective technique for more successful PLP management.

Clinical-functional features of individuals with Osteogenesis Imperfecta and Ehlers-Danlos syndromes: A scoping review of assessment tools and ICF model.

BACKGROUND: Clinical-functional assessment of patients affected by Osteogenesis Imperfecta and Ehlers-Danlos Syndromes is essential for clinical management. However, there is no clear information on disease-specific tools of assessment for clinical practice, thus limiting quantification and management of the diseases-related impairments. OBJECTIVE: The present scoping review was aimed at investigating the most common clinical-functional features and assessment tools in individuals with Osteogenesis Imperfecta and Ehlers-Danlos Syndromes, and to provide an updated International Classification of Functioning (ICF) model related to functional impairments for each disease. METHODS: The literature revision was conducted on PubMed, Scopus and Embase databases. Articles reporting an ICF model of clinical-functional features and assessment tools for Osteogenesis Imperfecta and Ehlers-Danlos Syndromes individuals were included. RESULTS: A total of 27 articles were included, 7 reporting an ICF model, and 20 reporting clinical-functional assessment tools. It was reported that patients with Osteogenesis Imperfecta and Ehlers-Danlos Syndromes show impairments in both Body Function and Structure, and Activities and Participation domains of the ICF. A heterogeneous number of assessment tools was found for both diseases regarding proprioception, pain, endurance to exercise, fatigue, balance and motor coordination, and mobility. CONCLUSION: Patients with Osteogenesis Imperfecta and Ehlers-Danlos Syndromes show several impairments and limitations in Body Function and Structure, and Activities and Participation domains of the ICF. Thus, an appropriate and ongoing assessment of the disease-related impairments is necessary to improve clinical practice. Several functional tests and clinical scales can be used to assess the patients despite the heterogeneity of assessment tools found in previous literature.

Differences in hip musculoskeletal loads between limbs during daily activities in patients with 3D-printed hemipelvic reconstructions following tumor surgery.

BACKGROUND: Anatomical custom-made prostheses, thanks to computer-aided design and 3D-printing technology, help improve osseointegration and reduce mechanical complications in bone reconstructions following bone tumors. A recent quantitative analysis of long-term recovery in patients with 3D-printed reconstructions following pelvic tumor surgery showed asymmetries in ground reaction forces between limbs during different motor activities, while standing very good motor performance and quality of life. RESEARCH QUESTION: We analyzed hip contact forces and muscle forces in that cohort of six patients with an innovative custom-made reconstruction of the hemipelvis, and we tested the hypothesis that asymmetries in ground reaction forces would result in more marked differences in musculoskeletal forces. METHODS: State-of-the-art musculoskeletal modeling in an optimization-based inverse-dynamics workflow was used to calculate hip contact forces and muscle forces during five motor activities, and the differences between limbs were statistically evaluated across the motor activity cycles and on the force peaks. RESULTS: The musculoskeletal loads were found to be not symmetric, as hip loads were generally higher in the contralateral limb. We found significant differences in considerable portions of the motor activities cycles except squat, load symmetry indices indicating a load increase (median up to 25%) on the contralateral limb, especially during stair descent and chair rise/sit, and significantly higher values in the contralateral limb at force peaks. SIGNIFICANCE: We confirmed the hypothesis that residual asymmetries found in ground reaction forces were amplified when hip musculoskeletal loads were investigated, reflecting a shift of the loads toward the intact limb. Despite the general trend of higher loads found in the contralateral hip, this cannot be considered a risk of overloading, as both hips supported loads in a physiological range or lower, indicating a likely optimal recovery.

Influence of Coaching on Effectiveness, Participation, and Safety of an Exercise Program for Postmenopausal Women with Osteoporosis: A Randomized Trial.

Purpose: We compared two different strategies providing professional coaching to administer an exercise program for women with postmenopausal osteoporosis (POP): individual training (IT) at home with trainer's supervision provided by telephone contacts at regular time-intervals or group training (GT) with trainer's live supervision. Our working hypothesis was that IT is a valid alternative to GT when GT is not feasible. Patients and Methods: This was a single-blind, randomized study. We recruited 52 women with POP, without significant comorbidity, and no participation in any structured exercise program within the previous 6 months. They were assigned randomly to IT or GT groups (n = 26 each). Distribution of age (IT: 68±4, GT: 67±8 years) and body mass index (IT: 23.0±2.5, GT: 21.4±5.1) was similar between groups. Each group performed the exercise program in two 1-hour sessions per week for 18 months. Primary outcome measure was Health-Related Quality of Life (HRQoL), as measured by the Short Osteoporosis Quality of Life Questionnaire. Secondary outcome measures focused on domains acknowledged to influence HRQoL (disability, fear of falling, weekly physical activity, physical function) or the effectiveness of the exercise program (retention, adherence, and safety). Significance level was set at p < 0.05. Results: No significant differences were observed between IT and GT groups for any domain. Retention, adherence, and safety were also similar. HRQoL, disability and fear of falling did not change between baseline and follow-up for either group. However, for both groups, physical function (knee flexion, shoulder mobility) and functional capacity (6-minute walking test) improved. Weekly physical activity levels increased from moderate range at baseline to intense at final assessment for both groups. Conclusion: IT and GT supervised exercise programs for women with POP provide similar effectiveness, participation and safety. Hence, both modalities should be considered for future translation in clinical practice of exercise recommendations for POP.

Gait Alterations in Two Young Siblings with Progressive Pseudorheumatoid Dysplasia.

Progressive pseudorheumatoid dysplasia (PPRD) is an autosomal recessive inherited skeletal dysplasia characterized by progressive non-inflammatory arthropathy affecting primarily the articular cartilage. Currently, little is known about the functional musculoskeletal aspects of these patients. In particular, an abnormal gait pattern has been described, without a clear hypothesis of the underlying causes in terms of muscular activity. This study presents the case of two siblings, 4 and 9 years old, a boy and a girl, respectively, suffering from PPRD at different stages of the disease. In addition to the clinical assessment, an instrumental gait analysis was performed. Swelling of the interphalangeal finger joints and fatigue were present in both cases. Gait abnormalities consisted of a relevant reduction in the ankle plantarflexion in the terminal phase of the gait cycle, associated with reduced gastrocnemius EMG activity and increased activity of the tibialis anterior, resulting in overloading at the initial peak of ground reaction forces. Gait anomalies observed were similar in both siblings with PPRD, although at different ages, and confirm walking patterns previously described in the literature. The calf muscle strength deficit and reduced activity during the stance phase of gait present in these two siblings indicate the typical absence of the propulsive phase. A stomping gait pattern, with the foot striking the ground hard on each step, was originally described. Further neurophysiological investigations are required to determine the origin of muscle weakness.

Hip subluxation in Italian cerebral palsy children and its determinants: a retrospective cohort study.

The study's aim was two-fold: to describe the trend of hip subluxation in the largest sample of Italian nonambulatory cerebral palsy (CP) children ever published; to investigate its determinants. This single-centre retrospective cohort study included patients with spastic or dyskinetic CP, Gross Motor Function Classification System (GMFCS) level IV or V, age 0-18 years, having been referred to our unit before March 2020. The hip subluxation was measured by means of the migration percentage (MP). Other data were gathered such as sex, CP subtype, GMFCS level, presence of drug-resistant epilepsy, age, use of walkers with weight relief or standing devices, previous botulinum injection or hip surgery, oral or intrathecal baclofen and hip pain. Multiple linear stepwise regression was performed and descriptive statistics are provided. Spastic CP had MP maximum increase in early ages, with GMFCS level V values persistently higher than level IV. The dyskinetic subtype showed a slower increase of the MP, with GMFCS level IV presenting similar or higher values, compared to level V. Age, CP severity and spastic subtype are the main determinants. The stepwise multiple regression analysis demonstrated that weight relief walking and standing assistive devices, combined with botulinum contributed to reduce the MP progression. Dyskinetic CP showed overall lower MP values and a more variable behaviour relative to age and GMFCS level, compared to the spastic subtype. Standing and walking assistive devices, with partial or total weight relief, combined with individually targeted botulinum injections, should be considered in the management of bilateral nonambulatory CP patients, to prevent hip subluxation or its recurrence after surgery.

Mobile-Bearing Total Ankle Replacement In Vivo Kinematic Assessment: A Prospective Study Protocol.

Total ankle prosthesis as a surgical solution in the case of end-stage osteoarthritis has seen a considerable increase in the last two decades. This study protocol arises from the need to understand the in vivo kinematics of mobile-bearing, flat tibial component total ankle replacement, evaluating the real range of motion and the reciprocal relationships between the components during normal motor tasks through the use of model-based radio-stereometric analysis (MB-RSA). In addition, pre- and post-operative evaluation of walking kinematics with inertial motion sensors, proprioception through a dedicated workstation, and clinical outcomes are discussed. We expect that based on our study protocol researchers will be able to improve future prosthetic designs and validate the setup of MB-RSA, as well as to understand "how an ankle prosthesis moves" once implanted in the patient.

Long-term functional recovery in patients with custom-made 3D-printed anatomical pelvic prostheses following bone tumor excision.

BACKGROUND: Anatomical custom-made prostheses make it possible to reconstruct complicated bone defects following excision of bone tumors, thanks to 3D-printed technology. To date, clinical measures have been used to report clinical-functional outcome and provide evidence for the effectiveness of this new surgical approach. However, there are no studies that quantified the achievable recovery during common activities by using instrumental clinical-functional evaluation in these patients. RESEARCH QUESTION: What is the motor performance, functional outcome and quality of life in patients with custom-made 3D-printed pelvic prostheses following bone tumor? METHODS: To analyze motor performance, six patients performed motion analysis during five motor activities at follow-up of 32 ± 18 months. Joint angles, ground reaction forces and joint moments of the operated and contralateral limbs were compared. On-off activity of lower-limb muscles were calculated from electromyography and compared to a healthy matched population. To analyze functional outcome and quality of life, differences in measured hip abductor strength between limbs were evaluated, as well as clinical-functional scores (Harris Hip Score, Barthel Index, Musculoskeletal Tumor Society score), and quality of life (SF-36 health survey). RESULTS: We found only slight differences in joint kinematics when comparing operated and contralateral limb. The activity of gluteal muscles was normal, while hamstrings showed out-of-phase activities. Ground reaction forces and hip moments showed asymmetries between limbs, particularly in more demanding motor activities. We found a mean difference in hip abductor strength of 48 ± 82 N between limbs, good clinical-functional scores, and quality of life scores within normative. SIGNIFICANCE: Our study showed optimal long-term results in functional recovery, mainly achieved through recovery of the gluteal function, although minor impairments were found, which may be considered for future improvement of this innovative surgery. The effect of a more loaded contralateral limb on internal loads and long-term performance of the implant remains unknown and deserves further investigation.

A retrospective cohort study about hip luxation in non-ambulatory cerebral palsy patients: The point of no return.

Purpose: The migration percentage is a widely used criterion for surgery in displaced hips. Literature suggests that no hip can spontaneously improve if the migration percentage exceeds 45%, in a mixed population of cerebral palsy children. The aim of the present article was to identify the point of no return of the migration percentage in a selected sample of non-ambulatory cerebral palsy children, being the most exposed to hip luxation. Methods: This single-center retrospective cohort study included patients with spastic or dyskinetic cerebral palsy, Gross Motor Function Classification System level IV or V, age 0-18, having at least three pelvic radiographies, excluding radiographies relative to hips having previously undergone surgery. The following information was collected: sex, cerebral palsy subtype, Gross Motor Function Classification System level, presence of drug-resistant epilepsy, migration percentage, age at assessment, use of walking or standing assistive devices, previous botulinum injection, oral or intrathecal baclofen, and hip pain. Data were analyzed at the level of the individual hips. Descriptive statistics were presented. Receiver operating characteristic curve analysis was conducted to investigate which value of the migration percentage could be adopted as the "point of no return": that is, the cutoff value beyond which no migration percentage reduction, by more than 5%, could be expected. Results: The optimal cutoff value was identified as migration percentage ≥50%, with a sensitivity of 84.5% and a specificity of 100% (p-value <0.001). Conclusion: Based on the present study, migration percentage ≥50% is the "point of no return" for Gross Motor Function Classification System IV-V cerebral palsy patients, representing the cutoff value beyond which no spontaneous cerebral palsy reduction may be expected, unless addressing surgery. Level of evidence: level II-retrospective study.