Aims

This cross-sectional study aimed to investigate the in vivo ankle kinetic alterations in patients with concomitant chronic ankle instability (CAI) and osteochondral lesion of the talus (OLT), which may offer opportunities for clinician intervention in treatment and rehabilitation.

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The sensitivity and specificity of electrodiagnostic parameters in diagnosing carpal tunnel syndrome (CTS) have been reported differently, and this study aims to address this gap.

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To systematically review the efficacy of split tendon transfer surgery on gait-related outcomes for children and adolescents with cerebral palsy (CP) and spastic equinovarus foot deformity.

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The conventionally described mechanism of distal biceps tendon rupture (DBTR) is of a ‘considerable extension force suddenly applied to a resisting, actively flexed forearm’. This has been commonly paraphrased as an ‘eccentric contracture to a flexed elbow’. Both definitions have been frequently used in the literature with little objective analysis or citation. The aim of the present study was to use video footage of real time distal biceps ruptures to revisit and objectively define the mechanism of injury.

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To fully quantify the effect of posterior tibial slope (PTS) angles on joint kinematics and contact mechanics of intact and anterior cruciate ligament-deficient (ACLD) knees during the gait cycle.

Aims. This study aimed to use intraoperative free electromyography to examine how the placement of a retractor at different positions along the anterior acetabular wall may affect the femoral nerve during total hip arthroplasty (THA) when undertaken using the direct anterior approach (THA-DAA). Methods. Intraoperative free electromyography was performed during primary THA-DAA in 82 patients (94 hips). The highest position of the anterior acetabular wall was defined as the “12 o’clock” position (middle position) when the patient was in supine position. After exposure of the acetabulum, a retractor was sequentially placed at the ten, 11, 12, one, and two o’clock positions (right hip; from superior to inferior positions). Action potentials in the femoral nerve were monitored with each placement, and the incidence of positive reactions (defined as explosive, frequent, or continuous action potentials, indicating that the nerve was being compressed) were recorded as the primary outcome. Secondary outcomes included the incidence of positive reactions caused by removing the femoral head, and by placing a retractor during femoral exposure; and the incidence of femoral nerve palsy, as detected using manual testing of the strength of the quadriceps muscle. Results. Positive reactions were significantly less frequent when the retractor was placed at the ten (15/94; 16.0%), 11 (12/94; 12.8%), or 12 o’clock positions (19/94; 20.2%), than at the one (37/94; 39.4%) or two o’clock positions (39/94; 41.5%) (p < 0.050). Positive reactions also occurred when the femoral head was removed (28/94; 29.8%), and when a retractor was placed around the proximal femur (34/94; 36.2%) or medial femur (27/94; 28.7%) during femoral exposure. After surgery, no patient had reduced strength in the quadriceps muscle. Conclusion. Placing the anterior acetabular retractor at the one or two o’clock positions (right hip; inferior positions) during THA-DAA can increase the rate of electromyographic signal changes in the femoral nerve. Thus, placing a retractor in these positions may increased the risk of the development of a femoral nerve palsy. Cite this article: Bone Joint J 2022;104-B(2):193–199

Upper limb amputations, ranging from transhumeral to partial hand, can be devastating for patients, their families, and society. Modern paradigm shifts have focused on reconstructive options after upper extremity limb loss, rather than considering the amputation an ablative procedure. Surgical advancements such as targeted muscle reinnervation and regenerative peripheral nerve interface, in combination with technological development of modern prosthetics, have expanded options for patients after amputation. In the near future, advances such as osseointegration, implantable myoelectric sensors, and implantable nerve cuffs may become more widely used and may expand the options for prosthetic integration, myoelectric signal detection, and restoration of sensation. This review summarizes the current advancements in surgical techniques and prosthetics for upper limb amputees.

Cite this article: Bone Joint J 2021;103-B(3):430–439.

Aims

We aimed to address the question on whether there is a place for shoulder stabilization surgery in patients who had voluntary posterior instability starting in childhood and adolescence, and later becoming involuntary and uncontrollable.

Surgeries for reverse total shoulder arthroplasty (RTSA) significantly increased in the last ten years. Initially developed to treat patients with cuff tear arthropathy (CTA) and pseudoparalysis, wider indications for RTSA were described, especially complex proximal humerus fractures. We previously demonstrated in patients with CTA a different sequence of muscular activation than in normal shoulder, with a decrease in deltoid activation, a significant increase of upper trapezius activation and slight utility of the latissimus dorsi. There is no biomechanical study describing the muscular activity in patients with RTSA for fractures. The aim of this work is to describe the in vivo action of RTSA in patients with complex fractures of the proximal humerus. We conducted an observational prospective cohort study comparing 9 patients with RTSA for complex humerus fracture (surgery more than 6 months, healed tuberosities and rehabilitation process achieved) and 10 controls with normal shoulder function. Assessment consisted in a synchronized analysis of range of motion (ROM) and muscular activity on electromyography (EMG) with the use of 7 bipolar cutaneous electrodes, 38 reflective markers and 8 motion-recording cameras. Electromyographic results were standardized and presented in muscular activity (RMS) adjusted with maximal isometric contractions according to the direction tested. Five basic movements were evaluated (flexion, abduction, neutral external rotation, external rotation in 90° of abduction and internal rotation in 90° of abduction). Student t-test were used for comparative descriptive analysis (p < 0,05). The overall range of motion with RTSA is very good, but lower than the control group: flexion 155.6 ± 10 vs 172.2 ± 13.9, p<0.05, external rotation at 90° 55.6 ± 25 vs 85.6 ± 8.8, p<0,05, internal rotation at 90° 37.8 ± 15.6 vs 52.2 ± 12, p<0,05. The three heads of the deltoid are more stressed during flexion and abduction in the RTSA group (p. The increased use of the 3 deltoid chiefs does not support the hypothesis proposed by Grammont when the RTSA is performed for a complex proximal humerus fracture. This can be explained by the reduced dispalcement of the rotation center of the shoulder in these patients compared to those with CTA. These patients also didn't present shoulder stiffness before the fracture. The maximal muscle activity of the trapezius in flexion and of the latissimus dorsi in flexion and abduction had not been described to date. These new findings will help develop better targeted rehabilitation programs. In addition, the significant role of the latissimus dorsi must question the risks of its transfer (L'Episcopo procedure) to compensate for external rotation deficits

The role of anconeus in elbow stability has been a long-standing debate. Anatomical and electromyographic studies have suggested a potential role as a stabilizer. However, to our knowledge, no clinical or biomechanical studies have investigated its role in improving the stability of a lateral collateral ligament (LCL) deficient elbow. Seven cadaveric upper extremities were mounted in an elbow motion simulator in the varus position. An LCL injured model was created by sectioning of the common extensor origin, and the LCL. The anconeus tendon and its aponeurosis were sutured in a Krackow fashion and tensioned to 10N and 20N through a transosseous tunnel at its origin. Varus-valgus angles and ulnohumeral rotations were recorded using an electromagnetic tracking system during simulated active elbow flexion with the forearm pronated and supinated. During active motion, the injured model resulted in a significant increase in varus angulation (5.3°±2.9°, P=.0001 pronation, 3.5°±3.4°, P=.001 supination) and external rotation (ER) (8.6°±5.8°, P=.001 pronation, 7.1°±6.1°, P=.003 supination) of the ulnohumeral articulation compared to the control state (varus angle −2.8°±3.4° pronation, −3.3°±3.2° supination, ER angle 2.1°±5.6° pronation, 1.6°±5.8° supination). Tensioning of the anconeus significantly decreased the varus angulation (−1.2°±4.5°, P=.006 for 10N in pronation, −3.9°±4°, P=.0001 for 20N in pronation, −4.3°±4°, P=.0001 for 10N in supination, −5.3°±4.2°, P=.0001 for 20N in supination) and ER angle (2.6°±4.5°, P=.008 for 10N in pronation, 0.3°±5°, P=.0001 for 20N in pronation, 0.1°±5.3°, P=.0001 for 10N in supination, −0.8°±5.3°, P=.0001 for 20N in supination) of the injured elbow. Comparing anconeus tensioning to the control state, there was no significant difference in varus-valgus angulation except with anconeus tensioning to 20N with the forearm in supination which resulted in less varus angulation (P=1 for 10N in pronation, P=.267 for 20N in pronation, P=.604 for 10N in supination, P=.030 for 20N in supination). Although there were statistically significant differences in ulnohumeral rotation between anconeus tensioning and the control state (except with anconeus tensioning to 10N with the forearm in pronation which was not significantly different), anconeus tensioning resulted in decreased external rotation angle compared to the control state (P=1 for 10N in pronation, P=.020 for 20N in pronation, P=.033 for 10N in supination, P=.001 for 20N in supination). In the highly unstable varus elbow orientation, anconeus tensioning restores the in vitro stability of an LCL deficient elbow during simulated active motion with the forearm in both pronation and supination. Interestingly, there was a significant difference in varus-valgus angulation between 20N anconeus tensioning with the forearm supinated and the control state, with less varus angulation for the anconeus tensioning which suggests that loads less than 20N is sufficient to restore varus stability during active motion with the forearm supinated. Similarly, the significant difference observed in ulnohumeral rotation between anconeus tensioning and the control state suggests that lesser degrees of anconeus tensioning would be sufficient to restore the posterolateral instability of an LCL deficient elbow. These results may have several clinical implications such as a potential role for anconeus strengthening in managing symptomatic lateral elbow instability

Aims

The purpose of this study was to determine the functional outcome and implant survivorship of mobile-bearing total ankle arthroplasty (TAA) performed by a single surgeon.

Introduction. This paper describes the kinetic and electromyographic contribution of principal muscles around the shoulder of a cohort of patients with reverse total shoulder arthroplasty (RTSA). Surgeries for RTSA significantly increased in the last five years. Initially developed to treat patients with cuff tear arthropathy and pseudoparalysis, wider indications for RTSA were described (massive non repairable rotator cuff tears, complex 4-parts fractures). Since Grammont's theory in 1985, the precise biomechanics of the RTSA has not yet been demonstrated in vivo. Clinical results of patients with RSTA are still unpredictable and vary one from another. Methods. We conducted an observational prospective cohort study comparing 9 patients with RTSA (surgery more than 6 months and rehabilitation process achieved) and 8 controls with normal shoulder function adjusted for age, sex and dominance. Assessment consisted in a synchronized analysis of range of motion (ROM) and muscular activity on electromyography (EMG) with the use of 7 bipolar cutaneous electrodes, 38 reflective markers and 8 motion-recording cameras. Electromyographic results were standardized and presented in muscular activity (RMS) adjusted with maximal isometric contractions according to the direction tested. Five basic movements were evaluated (flexion, abduction, neutral external rotation, external rotation in 90° of abduction and internal rotation in 90° of abduction). Student t-test were used for comparative descriptive analysis (p<0,05). Results. ROM is limited in the RSTA group (flexion 128,5 vs 152,6, p=0,04; abduction 150 vs 166, p=0,02; neutral ext rot 28.3 vs 75.6, p<0,01; 90° ext rot 26,43 vs 70,63, p<0,01, int rot 27.5 vs 49.4, p=0,01). Anterior and middle deltoid shows less muscular activation in RTSA than in controls, sustaining the deltoid potentiation described by Grammont. Posterior deltoid shows decreased activity in external rotation movements in RTSA. Upper trapezius is the main activator in all directions with an early and constant activity in RTSA (p<0,01). Latissimus dorsi demonstrates increased muscular activity in internal rotation with RTSA (p<0,01). Discussion. The sequence of muscular activation in RTSA is different than in normal shoulder. Grammont's theory is confirmed with this study. The significant contribution of both the trapezius and latissimus dorsi has never been described until today. New rehabilitation protocols targeted on those muscle groups could demonstrate better and more homogenous clinical results

Background:. We have recently shown, using transcranial magnetic stimulation (TMS) to assess voluntary activation (VA), that neural drive to back muscles is reduced in subjects with chronic low back pain. There is also evidence that central nervous system drive to abdominal muscles is altered in these subjects, however VA has not yet been assessed for these muscles in healthy subjects; this is the purpose of the present study. Methods:. Twenty one healthy subjects (10M:11F) participated. Electromyographic activity was recorded from back and abdominal muscles and flexor torque was measured using a dynamometer. Subjects performed a series of isometric voluntary contractions (10%–100% MVC) of rectus abdominis during which TMS was applied to the motor cortex. The resulting superimposed twitches (SIT) were measured and VA was derived. Results:. There was a linear relationship between voluntary torque (50–100% MVC) and SIT amplitude and between voluntary torque (50–100% MVC) and VA. VA at a target torque of 100% MVC was less than maximal (∼86%). Time-to-peak amplitude of SITs displayed a linear relationship with voluntary torque between 10%–100% MVC. Discussion:. This study has shown that it is possible to assess VA of abdominal muscles using TMS. Further, it appears that VA is submaximal during maximum voluntary contractions, similar to that observed in back muscles. This may reflect the function of trunk muscles in general, which are routinely used for maintenance of posture. Whether imbalances of abdominal and back muscle strength observed in low back pain are reflected in imbalances of neural drive to these muscles remains to be investigated

The February 2014 Wrist & Hand Roundup³⁶⁰ looks at: simple debridement and ulnar-sided wrist pain; needle fasciotomy or collagenase injection; joint replacement in osteoarthritic knuckles; the Mannerfelt arthrodesis; scaphoid union rates with conservative treatment; the benefits of atorvastatin for muscle re-innervation after sciatic nerve transection; and complications of trapeziectomy.

The February 2014 Research Roundup³⁶⁰ looks at: blood supply to the femoral head after dislocation; diabetes and hip replacement; bone remodelling over two decades following hip replacement; sham surgery as good as arthroscopic meniscectomy; distraction in knee osteoarthritis; whether joint replacement prevent cardiac events; tranexamic acid and knee replacement haemostasis; cartilage colonisation in bipolar ankle grafts; CTs and proof of fusion; atorvastatin for muscle re-innervation after sciatic nerve transection; microfracture and short-term pain in cuff repair; promising early results from L-PRF augmented cuff repairs; and fatty degeneration in a rodent model.

Background:. It is not well known how different external loads influence shoulder kinematics and muscle activity in patients with shoulder prostheses. Study objective: define shoulder kinematics and determine the scapulothoracic contribution to total shoulder motion, in combination with shoulder muscle activity and the degree of co-contraction, of patients with total (TSA) and reverse shoulder arthroplasties (RSA) and healthy individuals during rehabilitation exercises using different loading conditions. Methods:. Shoulder motions (anteflexion and elevation in the scapular plane) of 17 patients (20 shoulders) with a TSA, 8 patients (9 shoulders) with a RSA and 15 healthy subjects were measured using anelectromagnetic tracking device. A force transducer recorded force signals during loaded conditions (without external load, 1 kg and elastic resistance). Electromyographic (EMG) activity of the deltoid (anterior, middle, posterior parts), latissimus dorsi, pectoralis major (clavicular and sternal parts), teres major and serratus anterior was recorded and the degree of co-contraction calculated. Results:. The scapula contributed more to movement of the arm in subjects with prostheses compared to healthy subjects and during loaded versus unloaded tasks. Glenohumeral elevation angles during anteflexion were significantly higher in the TSA than in the RSA group. Higher activity of the middle and posterior deltoid was found in the TSA group compared to healthy subjects and for the pectoralis major (sternal part) in the RSA group compared to TSA and healthy subjects. For all muscles, except the serratus anterior, activity was lower for unloaded tasks compared to 1 kg dumbbell and elastic band resistance. No main effect of group or load for degree of co-contraction was detected in both exercises. Conclusions:. Differences in contribution of the scapula to total shoulder motion between patients with different types of arthroplasties were not significant, but differed both compared to healthy subjects. Scapular kinematics of patients with shoulder arthroplasties were influenced by implementation of external loads, however, not by the type of load. There were no differences in muscle activity and degree of co-contraction between patient groups

Background. Alterations in the neural drive to trunk muscles have been implicated in low back pain (LBP). This is supported by evidence of reduced corticospinal excitability, delayed muscle activation, reduced endurance and enhanced fatigability of these muscles; whether these changes persist during pain free periods remain unclear. Neural drive (or voluntary activation-VA) can be measured using twitch interpolation and the aim of this study is to investigate if subjects with a history of LBP show reduced VA. Methods. Twenty five subjects participated (13 with a history of LBP, 12 controls). Back extensor torque was measured using a dynamometer and bilateral electromyographic (EMG) activity was recorded from erector spinae and rectus abdominis. Transcranial magnetic stimulation of the motor cortex was applied while the subject, lying prone, performed graded voluntary back extensions. VA was calculated from the size of the twitches evoked by the TMS and EMG data were analysed for evidence of altered neural drive. Results. The LBP typical VAS pain scores were 3.39±1.76(SD), with worst pain being 5.92±2.29. There were no differences in the physical activity scores between the groups. EMG data revealed no differences in the evoked responses at varying levels of voluntary torque. VA was not significantly different between the LBP and control groups (LBP: 85.30±6.45% vs C: 80.14±11.40%). Discussion. These data show that in our cohort of subjects with a history of LBP, their ability to fully activate their back muscles maximally is not reduced. Whether subjects with current LBP exhibit reduced VA remains to be established. No conflicts of interest. Funded by Imperial College London. This abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting

The aim of this study was to examine the loading of the other joints of the lower limb in patients with unilateral osteoarthritis (OA) of the knee. We recruited 20 patients with no other symptoms or deformity in the lower limbs from a consecutive cohort of patients awaiting knee replacement. Gait analysis and electromyographic recordings were performed to determine moments at both knees and hips, and contraction patterns in the medial and lateral quadriceps and hamstrings bilaterally. The speed of gait was reduced in the group with OA compared with the controls, but there were only minor differences in stance times between the limbs. Patients with OA of the knee had significant increases in adduction moment impulse at both knees and the contralateral hip (adjusted p-values: affected knee: p < 0.01, unaffected knee p = 0.048, contralateral hip p = 0.03), and significantly increased muscular co-contraction bilaterally compared with controls (all comparisons for co-contraction, p < 0.01). The other major weight-bearing joints are at risk from abnormal biomechanics in patients with unilateral OA of the knee. Cite this article: Bone Joint J 2013;95-B:348–53