Superficial Flexor Research Articles

ARCADE OF FLEXOR DIGITORUM SUPERFICIALIS MUSCLE: ANATOMICAL STUDY AND CLINICAL IMPLICATIONS.

ABSTRACTObjective:The arcade of the flexor digitorum superficialis muscle (FDS) is an anatomical structure which has not yet been widely studied and is a site of nerve compression. The aim of this study was to analyze the arcade of the FDS muscle and its relations with the median and anterior interosseous nerves through anatomic dissections. Method:Fifty arms from 25 adult cadavers (21 males and 4 females) were dissected; 18 were previously preserved in formalin and glycerin and 7 fresh specimens were dissected in the Laboratory of Anatomy. Results:The arcade of the superficial flexor muscle was identified in all dissected limbs. The radial and humeral heads were present in all specimens, and the ulnar head in 16 (32%). We identified two varieties of the arcade structure: a fibrous arcade in 32 specimens (64%), and a muscular arcade in 11 specimens (22%). In 4 specimens (8%) the arcade was very fine and so transparent that the nerve could be seen within the arcade. In 3 forearms the arcade was considered irregular because of discontinuity between the fibers that comprised this structure. Conclusion:The fibrous arcade of the FDS muscle may be a potential cause of nerve compression of the median and interosseous anterior nerves. Level of Evidence IV; Case series.

Spontaneous compartment syndrome in a patient receiving oral anticoagulation therapy

Compartment syndrome (CS) is an emergency condition caused by muscle necrosis that can lead to locomotor dysfunctions. Intra-fascial bleeding of a limb due to direct trauma, reduction of fractures, or tight casting or bandages may cause acute CS. Although acute CS has many causes, few cases of spontaneous CS have been reported in the literature without any apparent reasons. We present a case of a 53-year-old male who had a spontaneous CS in his right forearm. There was no any evidence of acute major or minor repetitive trauma. He had a history of taking multiple anticoagulants due to previous femoral artery repair and still uses anticoagulants. After evaluation, we performed fasciotomy and removed an organized hematoma between the deep and superficial flexor tendons. The patient has recovered completely without any relapse at the 2-year follow-up. Detailed information should be given to patients who are taking anticoagulants about acute CS.

Swan neck deformity due to chronic radial collateral ligament injury of the little finger proximal interphalangeal joint.

IV.

Histochemical Characteristics in Relation to Meat Quality Traits of Eight Major Muscles from Hanwoo Steers.

The objective of this study was to determine the relationship between composition of muscle fiber types and meat quality traits of eight major muscles from Hanwoo steers. Longissimus lumborum (LL), psoas major (PM), semimembranosus (SM), semitendinosus (ST), gluteus medius (GM), triceps brachii (TB), rectus abdominis (RA) and superficialis flexor (SF) muscles were obtained from 9 Hanwoo steers and subjected to histochemical analysis. There were significant (p<0.05) differences in fiber number percentage (FNP) and fiber area percentage (FAP) of fiber types among these 8 major muscles. SF had the highest FNP of type I (55.9%), followed by PM (46.4%), TB (45.4%), RA (38.5%), LD (36.8%), GM (36.0%), SM (22.2%), and ST (18.8%). FAP of type IIB ranged from 9.9% in SF to 58.7% in ST. Meat quality traits, including fat content, myoglobin content, collagen content, CIE L* and a*, drip and cooking loss, sarcomere length and Warner-Bratzler shear force, were all significantly (p<0.05) different among these muscles. Due to such diversities among these 8 muscles, lack of correlations were found between fiber type composition and meat quality traits. These results suggest that correlation for each individual muscle should be used to improve meat quality and profitability of retail beef cuts.

MACROANATOMICAL ASPECTS OF BRACHIAL PLEXUS AND ITS BRANCHES IN THE INDIGENOUS DUCK

The injury to the peripheral nervous system is common clinical problem especially injury to the wing is the most common in birds. The present study aimed to document the detailed features of the morphological structure and the innervations areas of the brachial plexus in indigenous duck (Anas platyrhynchos domesticus). A total of six mature indigenous ducks (three of them were male and three were female) were used in this study. After administering an anesthetic to the birds, the body cavities were opened. The birds were fixed with formaldehyde after draining of the blood. The nerves of the brachial plexus were dissected separately and photographed. The brachial plexus was formed by the union of the ventral branches of 14thand 15th cervical spinal nerve and 1st, 2nd and 3rd thoracic spinal nerves, which were confirmed by palpation and counting the cervical vertebrae. Present study revealed that few small and large branches originated from brachial plexus and innervated into the specific muscles and their adjacent structure. Five nerve roots formed three nerve trunks in the duck, which constitute the dorsal and ventral cords. The pectoral trunk and median-ulnar nerve originated from ventral cord, while dorsal cord gives axillary nerve continued as a radial nerve into the wing of duck. The axillary nerve innervated into to skin of the dorsal side of the wing and shoulder deltoideous muscles, coracobrachialis muscles and propatagiasis cervical muscles. The radial nerve innervated to the humuro-brachial and triceps muscles, extensor carpi radial and supinator muscles. The ulnar nerve innervated extensor aspect of joint, flexor carpi ulnar muscles and superficial flexor muscle. The median nerve innervated into the median surface of the brachial and metacarpal region, flexor carpi radial muscle, pronator teres muscles, superficial and profound digital flexor muscles. The general macroanatomical shape of the brachial plexus and the distribution of the nerves originating from this plexus displayed some differences from other birds.

Meat Tenderness Characteristics of Ten Major Muscles from Hanwoo Steers according to Quality Grades of Carcasses.

The objective of this study was to determine the influence of quality grade (QG) on meat tenderness characteristics of ten major muscles from Hanwoo steers. A total of 25 Hanwoo carcasses (5 carcasses × 5 QGs) were selected. Intramuscular fat content, collagen content, sarcomere length, and Warner-Bratzler shear force (WBSF) of Longissimus thoracis (LT), Longissimus lumborum (LL), Psoas major (PM), Semisponals (SS), Triceps brachii (TB), Semimembranosus (SM), Gluteus medius (GM), Rectus Abdominis (RA), Superficialis flexor (SF), and Internal and external intercostal (IC) were determined. IC had the highest fat content, followed by LT, RA, LL, PM, GM, SS, SF, TB, and SM. High-fat muscles such as LT, LL, IC, RA, and PM had significantly (p<0.05) different fat contents among QGs. Collagen contents were significantly (p<0.05) different among QGs. With decreasing QG, increasing collagen content was found in muscles. There were significant (p<0.05) differences in sarcomere length among QGs of several muscles. However, no significant (p>0.05) difference in sarcomere length was found among QGs for LL, PM, or RA muscle. PM had the lowest WBSF, followed by LL, LT, RA, IC, GM, SM, SF, SS, and TB. WBSF of QG 1++ was lower than that of QG 1 for SS, TB, and SM. All muscles of QG 1 showed lower WBSF than QG 3 except TB or IC. Results of this study suggested that differences in WBSF among these 10 muscles by QG were due to differences in collagen content and sarcomere length.

The Role of Dynamic Ultrasound in the Immediate Conservative Treatment of Volar Plate Injuries of the PIP Joint: A Series of 78 Patients

The management of volar plate avulsion fractures in the context of a stable joint and a bony fragment of less than 30% has traditionally been conservative. This study was performed to assess volar plate healing with high-resolution ultrasound in order to provide early full mobilization. Between January 2012 and December 2013, 78 patients with volar plate injuries of the proximal interphalangeal (PIP) joints (42 distortions and 36 dislocations) were treated conservatively in our department for volar plate avulsion fracture associated with stable joint and bony fragment inferior to 30% of the intra-articular surface assessed both by radiography and ultrasound. Conservative treatment included extension stop splinting for the first 2 weeks and Coban bandage until 6 weeks postinjury. However, it may be possible to modify the duration of extension stop splinting based on clinical and ultrasound findings (with no additional X-ray) performed every 2 weeks for the first 3 months and then at 4 months postinjury. Only patients with residual contracture at the 4-month assessment had prolonged follow-up in order to ensure adequate dynamic splint therapy. The amount of soft tissue oedema and the mobility of the volar plate were factors used to determine return to full mobilization. Mean extension-stop-splint wear was 16 ± 2 days. During the first 2 follow-up assessments, 4 patients were excluded from the study because of the instability of the PIP joint. One patient required refixation of a large fragment of 30%, 2 patients required superficial flexor tendon (FDS) tenodesis of the unstable volar plate in hyperextension and 1 other patient required arthrodesis of the PIP joint. In 51 patients, the postoperative follow-up was free of complications at 4 months. In 18 patients, flexion contracture of 20° (range 11°-40°) and oedema during follow-up required dynamic extension splints for 3 to 5 months. After this time, 5 patients had a residual contracture of 10° to 15°. Avulsion fractures of the volar plate at the PIP joint are common. In general, they have a good outcome using the conservative treatment with extension block splints. Flexion contracture is a common complication and may be reduced by immediate splints in full extension at night and Coban bandage during the day. High-resolution sonography is a convenient tool to evaluate palmar plate stability, to assess reduction of oedema, and thus to guide safe return to full range of movement.

Assessment of the Presence or Absence of Palmaris Longus and the Fifth Superficial Flexor Tendon in the Iranian Population : Are These Tendons Evolutionary ?

Assessment of the Presence or Absence of Palmaris Longus and the Fifth Superficial Flexor Tendon in the Iranian Population : Are These Tendons Evolutionary ?

Progressive shoulder-neck exercise on cervical muscle functions in middle-aged and senior patients with chronic neck pain.

Although neck pain is a common musculoskeletal disorder, there is no consensus on suitable exercise methods for middle-aged and senior patients with chronic neck pain. Therefore, this study investigated the effectiveness of a 6-week shoulder-neck exercise intervention program on cervical muscle function improvement in patients aged 45 years or older with chronic neck pain. The aim of the present study was to evaluate the effects of progressive shoulder-neck exercise on cervical muscle functions of middle-aged and senior patients with chronic neck pain. A randomized controlled single-blind trial. Rehabilitation department of a hospital. A total of 72 subjects aged ≥45 years with chronic neck pain were randomly allocated to either an experimental group (N.=36; age 57.3±8.74 years) or a control group (N.=36; age 58.15±8.17 years). The control group received only traditional physiotherapy, whereas the experimental group participated in a 6-week shoulder-neck exercise program consisting of cranio-cervical flexion and progressive resistance exercises in addition to receiving traditional physiotherapy. The muscle functions of subjects in both groups were tested before the experiment and also after the intervention program. The pretest and posttest measured the cranio-cervical flexion test (CCFT) and the superficial cervical muscle strength. After the intervention, the experimental group had a 56.48 point improvement in the performance index of the CCFT (P<0.001), a 1.71-kg improvement in superficial neck flexor strength (P<0.001), and a 2.52-kg improvement in superficial neck extensor strength (P<0.001), indicating that in 6-week intervention significantly influenced the improvement of cervical muscle functions. This study confirmed that the 6-week progressive shoulder-neck exercise program can effectively improve cervical muscle function in middle-aged and senior patients with chronic neck pain. Progressive shoulder-neck exercise might provide positive effect on deep and superficial neck muscle strength in patients with chronic neck pain. Therefore, this study may serve as a reference for the clinical rehabilitation of patients with chronic neck pain.

Effect of Low-Level Laser Therapy and Strength Training Protocol on Hand Grip by Dynamometry.

Introduction: The purpose of this study was to investigate the effect of low-level laser therapy (LLLT) - 660 nm and 904 nm - before grip strength protocol in healthy subjects. Methods: The study included 45 healthy volunteers with an average age of 22.7 (±1.4) years, subdivided into the following groups, control group: grip strength training associated with placebo LLLT; 660 nm group: LLLT (660 nm, 20 J/cm2, power of 30 mW, and beam area of 0.06 cm2, continuous, energy 1.2 J, and exposure time 40 seconds per point) before grip strength training and 904 nm group: LLLT (904 nm, 10 J/cm2, peak power of 70 W and 0.13 cm2 beam area, with pulsed beam 9.500 Hz and 30 seconds of exposure time per point and emitted energy 1.2 J) before grip strength training. The LLLT was timed to contact 10 points located in the region of the superficial and deep flexor muscles of the fingers, with a total energy of 12.0 J per session. For the strength training protocol, the volunteer exercised their fingers with the dominant hand on a small table, elbow flexed at 90°, forearm in neutral, using a light extension handle. The Oxford protocol was performed during four weeks. The grip strength was assessed using a dynamometer (Jamar™). The data were evaluated by the analysis of variance (ANOVA) statistical method. Results: In the comparison of intragroup evaluation, only the 904 nm group showed a difference compared to the baseline assessment after 4 weeks (P < 0.05), in the final intergroup evaluation, a difference was observed in the comparison between the control and 904 nm groups Conclusion: In conclusion, LLLT (904 nm) applied before resistance training was effective in gaining grip strength when compared to LLLT (660 nm) and isolated strength training after 4 weeks.

Active Trigger Points in the Cervical Musculature Determine the Altered Activation of Superficial Neck and Extensor Muscles in Women With Migraine.

Previous studies have demonstrated the presence of active trigger points (TrPs) in women with migraine reproducing their headache attacks. No study has investigated whether these TrPs can alter cervical muscle function in migraine. Our objective was to analyze differences in the activation of superficial neck flexor and extensor muscles in women with migraine considering the presence of active TrPs in the splenius capitis (SC), the upper trapezius (UT), and the sternocleidomastoid (SCM) muscles. Surface electromyography (EMG) was recorded from the superficial flexors (SCM and anterior scalene) and the extensor (SC, UT) muscles bilaterally as participants performed a staged task of cranio-cervical flexion (CCF; 5 contractions representing a progressive increase in CCF range of motion) in 70 women with migraine. They were stratified according to the presence or the absence of active TrPs in the SCM, the SC, or the UT musculature. A comparison of EMG normalized root mean square (RMS) values was conducted with a 2×5 analysis of covariance with the task level as the within-subject variable, group stratified by active TrPs as the between-subjects variable and the presence of neck pain as a covariable. All patients exhibited active TrPs in their cervical muscles, which reproduced their migraine. Women with migraine exhibiting active TrPs in the SCM (P<0.01), the UT (P<0.05), or the SC (P<0.05) muscles had lower normalized RMS values of their superficial neck flexors than those without active TrPs in the same muscles. In addition, individuals exhibiting active TrPs in the SC and the UT (both, P<0.05) muscles had higher normalized RMS values in the SC muscle than those without active TrPs in the same muscles. The presence of active TrPs in the cervical musculature determines an altered activation of superficial neck and extensor muscles during low-load, isometric CCF contractions in women with migraine.

Superficial flexor tendon of ring transfer to reconstruct thumb opponensplasty: a long-term following up

Objective To evaluate the long term results of tendon transfer using superficial flexor tendon of ring to reconstruct thumb opponensplasty. Methods Eleven patients were treated by using superficial flexor tendon of ring to reconstruct thumb opponensplasty in hand surgery department of China-Japan Union Hospital of Jilin University from September, 2008 to December, 2010. The effect of thumb opponensplasty after operation by subjective and objective evaluation, and the data were analyzed retrospectively. Results The preoperative DASH score of 11 patients was 34.0±2.0, and postoperative DASH score was 19.7±1.9(P<0.05) after 67(64-71) months; the functional grade of thumb opponensplasty was excellent in 8 cases, good in 3 cases. Conclusion Through 67 months of follow-up evaluation, that the superficial flexor tendon of ring transferring to reconstruct of thumb opponensplasty is an accurate and reliable surgical method is confirmed. Key words: Thumb; Opponensplasty; Superficial flexor tendon; Transfer; Follow-up

Effects of manipulation of the thorax and intensity of the pressure biofeedback unit on the superficial cervical flexors muscle during craniocervical flexion exercise

[Purpose] This study examined the effects of manipulation of the thorax and the intensity of the pressure biofeedback unit on the superficial cervical flexors muscle during craniocervical flexion exercise. [Subjects and Methods] Thirty three subjects participated in the experiment. Thirty three healthy people without any orthopedic history were also selected. The subjects could monitor the pressure applied to cervical vertebra 3 of the craniocervical junction by markings on the pressure biofeedback unit. Craniocervical flexion exercise was performed for 20 seconds per pressure, and two minutes of rest was allowed after exercise to reduce muscle fatigue. [Results] Significant differences in the post-training gains in the sternocleidomastoid and scalene were observed between the thorax fixation group and thorax non-fixation group. The thorax fixation group showed that muscle activation of the sternocleidomastoid and scalene was increased when the pressure biofeedback unit intensity was 40 mmHg than when pressure biofeedback unit intensity was 20 mmHg and 30 mmHg in the post-hoc result. The thorax non-fixation group showed that muscle activation of the sternocleidomastoid and scalene was higher when the pressure biofeedback unit intensity was 40mmHg compared to that when the pressure biofeedback unit intensity was 20mmHg in the post-hoc result. [Conclusion] Craniocervical flexion exercise is a clinically effective method that reduces the superficial neck flexor muscle activation.

Resistance training minimizes the biomechanical effects of aging in three different rat tendons

Aging process is characterized by a decline in the organism functionality, especially in the decrease of muscle function, which also affects tendons. On the other hand, the resistance training (RT) has been used as an important tool to increase muscle and tendineous function during aging. Thus, this study aim has been to verify the effects of RT on the biomechanical properties of three different aged rat tendons. For this purpose, 20 wistar rats have been divided into four groups (5 rats per group): young sedentary (YS), trained (YT), old sedentary (OS) and old trained (OT). The RT has been performed through climb protocol for 12 weeks. After RT, the calcaneal tendon (CT), superficial flexor tendon (SFT) and deep flexor tendon (DFT) have been used for analysis. The results indicate that the RT in aged rats can prevent tendon function decrease (p<0.05). Although RT has prompted significant biomechanical changes in trained aged rats, there has been no increase in cross-section area or tendon stiffness reduction. Thus, the OT group showed better biomechanical responses when compared with OS (p<0.05). Therefore, RT can be used as an excellent strategy for increasing in tendon capacity during aging.

Mini-Open In Situ Cubital Tunnel Release

Cubital tunnel syndrome is the second most common nerve entrapment syndrome of the upper extremity. Patients typically present with numbness and paresthesias in the ring and small fingers, elbow pain, and intrinsic weakness. There are several surgical treatment options, including in situ decompression, medial epicondylectomy, subcutaneous transposition, and submuscular transposition. Potential complications include incomplete release, hematoma formation, and medial antebrachial cutaneous nerve injury. Recently, many authors have described an endoscopic cubital tunnel release that is performed through a smaller incision, is less invasive, and results in a faster recovery time. We describe a simple mini-open in situ release for ulnar nerve compression at the elbow. A 1 cm incision just posterior to the medial epicondyle is made and blunt dissection is utilized. The ulnar nerve is released on its posterior aspect under direct visualization. A Langenbeck retractor and Jameson tenotomy scissors are used to release the nerve proximally. The superficial and deep flexor carpi ulnaris fascia are released distally. This mini-open technique uses a smaller incision than the endoscopic technique, without the added cost of the endoscopic equipment.

Functional Result of Tendon Transfers and Releases for the Upper Extremity in Spastic Hemiplegic Cerebral Palsy

Purpose: To evaluate the functional and postural outcomes with Shriners Hospital for Children Upper Extremity Evaluation (SHUEE) Test, stereognosis of tendon transfers, and releases for the upper extremity, in adolescents with spastic hemiplegic cerebral palsy (CP). Material and Methods: Prospective study of 11 patients with spastic hemiplegic CP, 8 men, 4 female, between 10 and 16 years of age (mean, 13 years). Inclusion criteria were no fixed articular deformity and patients capable to follow instructions. Surgery consists in a one-time procedure of tendon transfers and releases according to SHUEE and clinical preoperative evaluation. Surgical procedures were done considering individual evaluations as follows: adductor pollicis (AP) release and extensor pollicis longus (EPL) rerouting, 11 patients; extensor carpi ulnaris (ECU) to extensor carpi radialis longus transfer (ECRL), 6 patients; flexor carpi ulnaris (FCU) to extensor carpi radialis brevis (ECRB) transfer, 3 patients; pronator teres (PT) rerouting, 4 patients; release of the FCU, 3 patients; release of the PT, 4 patients; superficial finger flexor tendons release, 3 patients; and swan deformity correction, 3 patients. Before tendon transfer, muscles were previously assed by dynamic electromyography to confirm phasic behavior. Postoperative protocol includes 1-month cast immobilization followed by 20 sessions of physical therapy, orthotic, and scar compression. Assessment with SHUEE, 12-element stereognosis test, and HOUSE classification (JH House) were done at preoperative, 6 and 12 months after surgery. Results: Friedman analysis of the 3 sections of the SHUEE was done. The spontaneous functional analysis of SHUEE (SFA) improves from 53% preoperative to 62% at 12 month of surgery, which was not significant ( P, .12). Dynamic positional analysis (DPA) improves significantly from 53% preoperative to 64% at 6 months and 76% at 12 months of surgery ( P, .004), the best result was in wrist and the worse was thumb. There were significant improvements of the grasp and release analysis (GRA) from 82% to 100% at 12 months ( P, .002). No significant changes in stereognosis were observed improving from 50% to 75% ( P, .05). Functional classification of HOUSE before surgery was 3 to 7. All patients improved their function in HOUSE scale 1 or 2 levels at 6 months and 1 to 3 levels at 12 month. Conclusions: Tendon transfers and releases for the upper extremity in spastic hemiplegic CP adolescents without fixed articular deformities improves dynamic position, grasp and release, and HOUSE level of function.

Nonconventional Tendon Advance for Injuries in Zones 1 and 2

Objective: Two techniques for reconstruction of tendon flexor injuries in zones 1 and 2 of Verdan in which primary suture cannot take place are presented. These techniques consists in carrying out a zetaplasty of the injured tendon in zone 5 to slide the proximal stump of the original rupture toward the distal stump of the tendon, suture both stump, and then perform the suture of the zetaplasty with the required tension. Another option, in case the end to end suture is unable, is to suture the lengthened tendon to an uninjured superficial flexor tendon. Methods: Thirteen patients with an average of 29 years of age were operated on with these two techniques. Diagnoses included 3 failures in primary suture of profundus flexor tendon, 7 tendon injuries treated 4 weeks after the trauma, and 3 injuries with shortening of the distal stump greater than 3 cm. In 7 cases, zetaplasty was performed with an end to end suture of the same flexor tendon, and in the remaining 6 zetaplasty was carried out with a suture of the proximal stump to an uninjured flexor tendon. Results: Average follow-up was 17.23 months. Assessment with the Strickand’s evaluation system yielded the following results: 8 excellent, 4 good, and 1 poor. Conclusions: The encouraging results in the short term with these techniques of shorter operating time and less surgical requirement motivate further development. A larger number of cases are necessary to obtain more reliable conclusions about their advantages and side effects.

Predictors of outcome after primary flexor tendon repair in zone 1, 2 and 3.

We retrospectively reviewed the outcomes of flexor tendon repairs in zones 1, 2 and 3 in 356 fingers in 291 patients between 2005 and 2010. The mean (standard deviation) active ranges of motion of two interphalangeal joints of the fingers were 98° (40) and 114° (45) at 8 weeks postoperatively and at the last follow-up (mean 7 months, range 3-98), respectively. Using the Strickland criteria, 'excellent' or 'good' function was obtained in 95 (30%) out of 322 fingers at 8 weeks and 107 (48%) out of 225 fingers at the last follow-up. A total of 48 (13%) fingers required reoperation because of rupture, adhesion, contracture or other complications. The prevalence of rupture was 4%. We carried out multiple linear regression analysis to identify the predictors of the active digital motion. The following variables were found as negative predictors: age; smoking; injury localization between subzones 1C and 2C; injury to the little finger; the extent of soft tissue damage; concomitant skeletal injury; delay to surgery; use of a 2-strand Kessler repair technique; attempted suture or preservation of the tendon sheath-pulley system; and resecting or leaving the concomitant superficial flexor tendon cuts untreated. Analysing the 8 weeks results of tendon repairs in zones 1 and 2, early active mobilization was found to be superior to Kleinert's regime. III.

Does increased superficial neck flexor activity in the craniocervical flexion test reflect reduced deep flexor activity in people with neck pain?

BackgroundThe craniocervical flexion test assesses the deep cervical flexor muscles (longus capitis, longus colli). Ideally, electromyography (EMG) studies measure activity in both deep and superficial (sternocleidomastoid, anterior scalene) flexors during the test, but most studies confine recordings to superficial muscle activity as the technique to record the deep muscles is invasive. Higher activity of the superficial flexors has been interpreted as an indicator of reduced deep flexor activity in people with neck pain but how close the inverse relationship is during this test is unknown. MethodsEMG was recorded from the sternocleidomastoid, anterior scalene and deep cervical flexor muscles to quantify their relationship during the craniocervical flexion test, from 32 women (age: 38.0 ± 11.6 yrs) with a history of chronic non-specific neck pain. The range of craniocervical flexion at each of the five test stages was also measured. ResultsA moderate negative correlation was identified (r = −0.45; P < 0.01) between the average normalized EMG amplitude of the deep cervical flexors and sternocleidomastoid across all stages of the craniocervical flexion test. There was a moderate although weaker and non-significant negative correlation between deep cervical flexors and anterior scalene activity (r = −0.34; P = 0.053). ConclusionsThe results affirm the interpretation that higher levels of activity of the superficial flexor muscles are an indicator of reduced deep cervical flexor activity in the craniocervical flexion test. Further studies of neuromuscular and movement strategies used by people with neck pain to compensate for poorer activation of the deep cervical flexors will inform best clinical assessment.

Biomechanical performance of Bio Cross-Pin and EndoButton for ACL reconstruction at femoral side: a porcine model

Introduction The method of graft fixation is critical in anterior cruciate ligament (ACL) reconstruction surgery. Success of surgery is totally dependent on the ability of the implant to secure the graft inside the bone tunnel until complete graft integration. The principle of EndoButton is based on the cortical suspension of the graft. The Cross-Pin is based on graft expansion. The aim of this study was to evaluate the biomechanical performance of EndoButton and Bio Cross-Pin to fix the hamstring graft at femoral side of porcine knee joints and evaluate whether they are able to support of loading applied on graft during immediate post-operative tasks. Methods Fourteen ACL reconstructions were carried out in porcine femurs fixing superficial flexor tendons with Titanium EndoButton (n = 7) and with 6 × 50 mm HA/PLLA Bio Cross-Pin (n = 7). A cyclic loading test was applied with 50-250 N of tensile force at 1 Hz for 1000 cycles. The displacement was measured at 20, 100, 500 and 1000 load cycles to quantify the slippage of the graft during the test. Single-cycle load-to-failure test was performed at 50 N/mm to measure fixation strength. Results The laxity during cyclic loading and the displacement to failure during single-cycle test were lower for the Bio Cross-Pin fixation (8.21 ± 1.72 mm) than the EndoButton (11.20 ± 2.00 mm). The Bio Cross-Pin (112.22 ± 21.20 N.mm–1) was significantly stiffer than the EndoButton fixation (60.50 ±10.38 N.mm–1). There was no significant difference between Bio Cross-Pin (failure loading: 758.29 ± 188.05 N; yield loading: 713.67 ± 192.56 N) and EndoButton strength (failure loading: 672.52 ± 66.56 N; yield loading: 599.91 ± 59.64 N). Both are able to support the immediate post-operative loading applied (445 N). Conclusion The results obtained in this experiment indicate that the Bio Cross-Pin technique promote stiffer fixation during cyclic loading as compared with EndoButton. Both techniques are able to support the immediate post-operative loading applied.