ACL microtrauma: healing through nutrition, modified sports training, and increased recovery time.

PURPOSE: Sports injuries among youth and adolescent athletes are a growing concern, particularly at the knee. Based on our current understanding of microtrauma and anterior cruciate ligament (ACL) healing characteristics, this clinical commentary describes a comprehensive plan to better manage ACL microtrauma and mitigate the likelihood of progression to a non-contact macrotraumatic ACL rupture. METHODS: Medical literature related to non-contact ACL injuries among youth and adolescent athletes, collagen and ACL extracellular matrix metabolism, ACL microtrauma and sudden failure, and concerns related to current sports training were reviewed and synthesized into a comprehensive intervention plan. RESULTS: With consideration for biopsychosocial model health factors, proper nutrition and modified sports training with increased recovery time, a comprehensive primary ACL injury prevention plan is described for the purpose of better managing ACL microtrauma, thereby reducing the incidence of non-contact macrotraumatic ACL rupture among youth and adolescent athletes. CONCLUSION: Preventing non-contact ACL injuries may require greater consideration for reducing accumulated ACL microtrauma. Proper nutrition including glycine-rich collagen peptides, or gelatin-vitamin C supplementation in combination with healthy sleep, and adjusted sports training periodization with increased recovery time may improve ACL extracellular matrix collagen deposition homeostasis, decreasing sudden non-contact ACL rupture incidence likelihood in youth and adolescent athletes. Successful implementation will require compliance from athletes, parents, coaches, the sports medicine healthcare team, and event organizers. Studies are needed to confirm the efficacy of these concepts. LEVEL OF EVIDENCE: V.

Optimal blocking screw placement for retrograde IM nail fixation of distal femur fracture: a standardized biomechanical study of "osteoporotic" synthetic bone.

PURPOSE: Intramedullary (IM) nail use for metaphyseal fracture management is problematic in long bones like the femur because the larger medullary cavity allows increased fracture motion and potentially increased implant failure and malunion/nonunion risk; Achieving effective distal femur fracture fixation is even more difficult in osteoporotic bone. Blocking screws to control IM nail movement are known to be effective for tibia fracture management. Few studies have evaluated IM nail and blocking screw use efficacy for distal femur fracture fixation in osteoporotic bone. METHODS: This study used an osteoporosis simulation synthetic bone model to evaluate retrograde IM nail fixation of a standardized non-comminuted, extra-articular distal femur fracture with and without blocking screws. The hypothesis was that use of one or two blocking screws would increase IM nail fixation stability as evidenced by greater peak IM nail load and lesser movement. A servohydraulic device under displacement control collected loading force versus movement deflection data. Shapiro-Wilk tests confirmed data normality. One-way analysis of variance and Tukey post hoc tests were used to compare condition specific loading force and movement differences. RESULT: In the coronal plane, blocking screw conditions displayed greater loading ranges (38.3 ± 2 vs. 19.1 ± 2 N, 100.5% difference) (p < 0.0001) and lesser movement (2.0 ± 0.3 vs. 6.86 ± 0.4 mm, 243% difference) (p < 0.0001). In the sagittal plane, the two blocking screw condition displayed a significantly greater loading magnitude (29.9 ± 6 vs. 20.8 ± 2.3 N, 43.8% difference) than the identical control condition without blocking screws (p = 0.018); however, movements were comparable (p = 0.82). Long-axis rotational loading failed to reveal load magnitude differences (p = 0.28); however, two different blocking screw conditions displayed decreased movement (1.32 ± 0.2 vs. 2.05 ± 0.3 mm, 53.8% difference) compared to other conditions (p ≤ 0.018). CONCLUSIONS: Use of one or two blocking screws on the medial and lateral sides of the IM nail decreased coronal plane movement in the intramedullary canal. Combining retrograde IM nail implantation with blocking screws reduced medial-lateral IM nail movement and increased fracture stability. These characteristics may help prevent fixation failure, malunion, and even nonunion in patients with a distal femur fracture in osteoporotic bone.

Distal thigh compression garment improves knee control and safety perceptions during single leg triple-hop for distance.

INTRODUCTION: Frontal plane knee control is essential to athletic knee injury prevention. AIM: To evaluate knee valgus frontal plane projection angle (FPPA), knee safety, and sports movement capability confidence during single leg triple hop for distance (SLTHD) under knee sleeve, distal thigh compression garment (DTCG), and no device (control) conditions. METHODS: A single-session, experimental study was performed using a within-subject design, and randomized device order. Two-dimensional FPPA measurements were collected during the final SLTHD landing of 18 healthy female college athletes for each condition. Sports movement capability and knee safety confidence were measured using 10-cm visual analog scale questions. One-way ANOVA assessed group differences, and Pearson correlations delineated FPPA, knee safety and sports movement capability confidence relationships (p < 0.05). RESULTS: The DTCG group had less valgus FPPA than the control group. The knee sleeve group had greater knee safety confidence than the control group. The DTCG (r = 0.48) had a moderate positive relationship between mean SLTHD and knee safety confidence. The DTCG group also had a moderate relationship between maximum SLTHD and knee safety confidence (r = 0.52). The DTCG and knee sleeve groups displayed moderate direct, and moderate inverse relationships between FPPA and sports movement capability confidence (r = 0.48 and r = -0.44, respectively). CONCLUSION: Reduced FPPA and relationships between maximum SLTHD magnitude and knee safety confidence, and between FPPA magnitude and sports movement capability confidence suggests that the DTCG may enhance pelvic deltoid kinesthetic acuity and dynamic knee stability through iliotibial tract compression. CLINICAL RELEVANCE: The DTCG was superior to the standard knee sleeve or control conditions for displaying characteristics that might better prevent knee injury, while still enabling effective sports movement capability.

Return to sports bridge program improves outcomes, decreases ipsilateral knee re-injury and contralateral knee injury rates post-ACL reconstruction.

PURPOSE: To present the results of a return to sports bridge program designed to reduce knee injuries following ACL reconstruction and physical therapy. METHODS: One hundred and fifty (male = 83, female = 67) patients participated in a whole body neuromuscular control, progressive resistance strength and agility training program. Post-program testing included functional movement form, dynamic knee stability, lower extremity power, agility, and sports skill assessments. Participants completed the Knee Outcome Survey-Sports Activity Scale (KOS-SAS) before and after program initiation. Pre-participation scores were re-estimated following program completion. RESULTS: Global rating KOS-SAS score at program entry was 75 ± 13. Post-program global rating and calculated KOS-SAS were 91.0 ± 9.8 and 90.9 ± 9.7, respectively (p < 0.0001). Pre-participation KOS-SAS score re-estimates at program completion were 54.5 ± 23.3 and 57.3 ± 18.5, respectively. The approximately 20% lower pre-program KOS-SAS score re-estimates (p < 0.0001) observed at program completion suggests that subjects had inaccurately high sports readiness perceptions at program entry. Perceived overall sports activity knee function ratings improved from 2.9 ± 0.6 (abnormal) at program entry to 1.3 ± 0.5 (normal) at completion (p < 0.0001). Most subjects returned back to sports at or above their pre-injury performance skill/performance level (84%, 126/150). By 6.8 ± 3.2 years (range = 2-13 years) post-surgery, ten subjects had sustained an ipsilateral knee re-injury or contralateral knee injury (6.7%). The 2.7% non-contact contralateral and 1.3% non-contact ipsilateral knee injury rates observed were significantly lower than those cited in previous reports. CONCLUSION: Supplementing primary ACL reconstruction and standard physical therapy with a return to sports bridge program prior to release to unrestricted sports performance was effective at improving patient outcomes and decreasing ipsilateral knee re-injury and contralateral knee injury rates. LEVEL OF EVIDENCE: II.

Leptin resistance elicits depressive-like behaviors in rats.

There is a growing appreciation that the complications of obesity extend to the central nervous system (CNS) and include increased risk for development of neuropsychiatric co-morbidities such as depressive illness. The neurological consequences of obesity may develop as a continuum and involve a progression of pathological features which is initiated by leptin resistance. Leptin resistance is a hallmark feature of obesity, but it is unknown whether leptin resistance or blockage of leptin action is casually linked to the neurological changes which underlie depressive-like phenotypes. Accordingly, the aim of the current study was to examine whether chronic administration of a pegylated leptin receptor antagonist (Peg-LRA) elicits depressive-like behaviors in adult male rats. Peg-LRA administration resulted in endocrine and metabolic features that are characteristic of an obesity phenotype. Peg-LRA rats also exhibited increased immobility in the forced swim test, depressive-like behaviors that were accompanied by indices of peripheral inflammation. These results demonstrate that leptin resistance elicits an obesity phenotype that is characterized by peripheral immune changes and depressive-like behaviors in rats, supporting the concept that co-morbid obesity and depressive illness develop as a continuum resulting from changes in the peripheral endocrine and metabolic milieu.

Preserving knee function following osteoarthritis diagnosis: a sustainability theory and social ecology clinical commentary.

To sustain natural systems, there must be an ongoing balance between environmental, social, and economic considerations. A key element of sustainability theory is to identify the most vulnerable surroundings. The most vulnerable knee tissue is the articular cartilage as it is the last line of osteoarthritis (OA) defense. This tissue has a poor capacity for healing. Based on sustainability theory and social ecology concepts we propose that several key factors contribute to knee function preservation. Factors include health history, genetic predisposition, personal behaviors, and socio-environmental factors in addition to local-regional-global physiological system function. Addressing only some of these factors or any one factor in isolation may lead to less than optimal treatment effectiveness. The purpose of this commentary is to introduce a medical, surgical and rehabilitation management approach for patients with knee OA that considers more than physical function improvement. This approach also considers social, emotional, and environmental factors to better ensure patient satisfaction, fulfilled expectations and successful outcomes. A clinical care pathway is presented for a 57-year-old patient with medial compartment knee OA who is contemplating early arthroplasty versus a knee function preservation treatment approach. Early arthroplasty refers to high revision likelihood based on a minimum 15 year prosthesis life-expectancy.

Sports involvement following ACL reconstruction is related to lower extremity neuromuscular adaptations, subjective knee function and health locus of control.

PURPOSE: This retrospective study compared the influence of perceived sports involvement on lower extremity neuromuscular adaptations during single-leg countermovement jumping (CMJ), perceived knee function and internal health locus of control (HLOC) scores at a minimum 2-year post-anterior cruciate ligament reconstruction. The hypothesis was that subjects with higher-level sports involvement would display significant differences compared to subjects with lower-level sports involvement. METHODS: Uninvolved and involved lower extremity EMG amplitude (1,000 Hz), vertical ground reaction force (VGRF) (500 Hz) and kinematic (60 Hz) displacement differences were determined during single-leg CMJ. These data and International Knee Documentation Committee subjective knee survey scores, Multidimensional Health Locus of Control Survey internal HLOC subscale scores and sports activity characteristics were compared by sports involvement level. RESULTS: Subjects that regarded themselves as only sporting sometimes (Group 3, n = 26) had lower IKDC survey and internal HLOC scores, were more likely to decrease sports activities by two intensity levels than highly competitive (Group 1, n = 20) and well-trained/frequently sporting (Group 2, n = 24) subjects, and had greater peak landing VGRF differences suggesting decreased involved lower extremity loading compared to Group 2. During propulsion, Group 1 had greater gluteus maximus (GM) and gastrocnemius (G) EMG differences than Groups 2 and 3. Groups 1 and 2 had decreased vastus medialis (VM) EMG differences during propulsion than Group 3. During landing, Group 1 had greater GM and G EMG differences than Group 3. CONCLUSION: Subjects with higher-level sports involvement up-regulated involved lower extremity GM and G activation and down-regulated VM activation. This adaptation may enable continued higher-level sports participation while minimizing knee joint forces. Perceived higher-level sports involvement was related to neuromuscular adaptations, better subjective knee function, a more internal HLOC and higher sports activity intensity. LEVEL OF EVIDENCE: Therapeutic case series, level IV.

Single-dose microparticle delivery of a malaria transmission-blocking vaccine elicits a long-lasting functional antibody response.

Malaria sexual stage and mosquito transmission-blocking vaccines (SSM-TBV) have recently gained prominence as a necessary tool for malaria eradication. SSM-TBVs are unique in that, with the exception of parasite gametocyte antigens, they primarily target parasite or mosquito midgut surface antigens expressed only inside the mosquito. As such, the primary perceived limitation of SSM-TBVs is that the absence of natural boosting following immunization will limit its efficacy, since the antigens are never presented to the human immune system. An ideal, safe SSM-TBV formulation must overcome this limitation. We provide a focused evaluation of relevant nano-/microparticle technologies that can be applied toward the development of leading SSM-TBV candidates, and data from a proof-of-concept study demonstrating that a single inoculation and controlled release of antigen in mice, can elicit long-lasting protective antibody titers. We conclude by identifying the remaining critical gaps in knowledge and opportunities for moving SSM-TBVs to the field.

Mechanisms involved in the p62-73 idiopeptide-modulated delay of lupus nephritis in SNF(1) mice.

The F(1) progeny of the (SWR × NZB) cross develop a lupus-like disease with high serum titers of autoantibodies, and increased frequency and severity of immune complex-mediated glomerulonephritis in females. In previous work, we found that an idiotypic peptide corresponding to aa62-73 (p62-73) of the heavy chain variable region of autoantibody 540 (Id(LN)F(1)) induced the proliferation of p62-73 idiotype-reactive T cell clones. Further, monthly immunization of pre-nephritic SNF(1) female mice with p62-73 resulted in decreased nephritis and prolonged life spans. Here we show that this treatment modulated proliferative responses to Id(LN)F(1) antigen, including a reduction in the population of idiopeptide-presenting antigen-presenting cells (APCs), as early as two weeks after immunization (10 weeks of age). Th1-type cytokine production was increased at 12 weeks of age. The incidence and severity of nephritis was reduced by 14 weeks compared to controls. Clinical indicators of nephritis, specifically histological evidence of glomerulonephritis and urine protein levels, were reduced by 20 weeks. Together these data suggest that events involved in the mechanism(s) whereby p62-73 immunization delayed nephritis occurred early after immunization, and involved modulation of APCs, B and T cell populations.

A nanobiological approach to nanotoxicology.

There is an urgent need to develop efficient and rapid strategies in order to characterize the potential health risks associated with nanomaterials, given the speed with which applications and uses are increasing. Use of standard toxicity methods will not be sufficient to meet this need. This article proposes the adoption of two novel guidances: the system's biological approach to toxicity testing advocated by the US National Research Council and a nanobiological perspective that identifies key events at the nanoscale that are relevant to signal transduction and structural biology.

Biomechanical and tissue handling property comparison of decellularized and cryopreserved tibialis anterior tendons following extreme incubation and rehydration.

Little is known regarding the biomechanical profiles and tissue handling properties of decellularized and cryopreserved human tibialis anterior tendons prepared as allografts for ACL reconstruction. This study compared allografts prepared using two extremes of the same cryoprotectant incubation and rehydration technique with a standardly prepared control group. Porcine tibiae with similar apparent BMD were randomly divided into three groups of ten specimens. Paired tendons were randomly divided into two experimental groups: Group 1 = 8 h incubation/15 min rehydration; Group 2 = 2 h incubation/1 h rehydration. Group 3 (control) consisted of ten standardly prepared tendons with 20 min rehydration. Tissue handling properties were graded during allograft preparation using a modified visual analog scale. Similar diameter allografts were fixed in matched diameter extraction drilled tibial tunnels with 35 mm long, 1 mm > tunnel diameter bioabsorbable interference screws. Potted constructs were mounted in a servo hydraulic device, pretensioned between 10-50 N at 0.1 Hz (10 cycles), and isometric pretensioned at 50 N for 1 min, prior to 500 submaximal loading cycles (50-250 N) at 0.5 Hz, and load to failure testing (20 mm/min). Constructs prepared under extreme conditions generally displayed comparable biomechanical properties to the control condition. Group 1 (8 h incubation/15 min rehydration)(-34 +/- 35 ms) and Group 2 (2 h incubation/1 h rehydration) (-22 +/- 38 ms) displayed smaller mean displacement-load peak phase timing differences over the initial ten cycles compared to Group 3 (control)(-42 +/- 49 ms), P = 0.004, suggesting greater relative construct stiffness. Group 1 (8 h incubation/15 min rehydration) (234.9 +/- 34 N/mm) and Group 2 (2 h incubation/1 h rehydration)(231.3 +/- 43 N/mm) displayed lower construct stiffness during load to failure testing than Group 3 (control)(284.5 +/- 25.2 N/mm), P = 0.003. Group 1 (8 h incubation/15 min rehydration) differed from Group 2 (2 h incubation/1 h rehydration) and Group 3 (control) for perceived tensile stiffness (2.4 +/- 2.0 vs. 7.0 +/- 0.5 and 7.9 +/- 0.3, respectively), compressive resilience (1.7 +/- 0.8 vs. 5.9 +/- 1.0 and 7.8 +/- 0.4, respectively), handling ease (2.8 +/- 1.0 vs. 6.5 +/- 0.5 and 7.0 +/- 0.7, respectively), color (2.6 +/- 0.8 vs. 4.7 +/- 0.7 and 5.1 +/- 0.3, respectively) and texture (4.0 +/- 0.8 vs. 6.2 +/- 0.8 and 6.8 +/- 0.8, respectively) (P < 0.0001). Group 2 (2 h incubation/1 h rehydration)(6.0 +/- 0.7 and 5.9 +/- 1.0, respectively) also differed from Group 3 (control)(6.8 +/- 0.8 and 7.8 +/- 0.4, respectively) for general "feel" and compressive resilience (P < 0.0001). Tensile stiffness and compressive resilience displayed moderate and weak relationships, respectively with displacement during submaximal cyclic loading (r2 = 0.78 and 0.58, respectively), stiffness (r2 = 0.33 and 0.44, respectively) and load at failure (r2 = 0.59 and 0.37, respectively) for Group 3 (control), but not for experimental Group 1 (8 h incubation/15 min rehydration) or Group 2 (2 h incubation/1 h rehydration). Knee surgeons should be aware that soft tissue tendon decellularization and cryopreservation may change the biomechanical stiffness, tissue handling properties, and relationships between these variables compared to standardly prepared allograft tissue.

Sports hernias: a systematic literature review.

This review summarises the existing knowledge about pathogenesis, differential diagnosis, conservative treatment, surgery and post-surgical rehabilitation of sports hernias. Sports hernias occur more often in men, usually during athletic activities that involve cutting, pivoting, kicking and sharp turns, such as those that occur during soccer, ice hockey or football. Sports hernias generally present an insidious onset, but with focused questioning a specific inciting incident may be identified. The likely causative factor is posterior inguinal wall weakening from excessive or high repetition shear forces applied through the pelvic attachments of poorly balanced hip adductor and abdominal muscle activation. There is currently no consensus as to what specifically constitutes this diagnosis. As it can be difficult to make a definitive diagnosis based on conventional physical examination, other methods, such as MRI and diagnostic ultrasonography are often used, primarily to exclude other conditions. Surgery seems to be more effective than conservative treatment, and laparoscopic techniques generally enable a quicker recovery time than open repair. However, in addition to better descriptions of surgical anatomy and procedures and conservative and post-surgical rehabilitation, well-designed research studies are needed, which include more detailed serial patient outcome measurements in addition to basing success solely on return to sports activity timing. Only with this information will we better understand sports hernia pathogenesis, verify superior surgical approaches, develop evidence-based screening and prevention strategies, and more effectively direct both conservative and post-surgical rehabilitation.

A cyclic testing comparison of FasT-Fix and RapidLoc devices in human cadaveric meniscus.

INTRODUCTION: Cyclic testing may provide a more valid depiction of how arthroscopic meniscal repairs will withstand the forces of activities of daily living (ADLs) and therapeutic exercises early post-surgery than single cycle load to failure testing. This study compared the meniscal fixation provided by vertically or horizontally placed FasT-Fix devices to horizontally placed RapidLoc devices under submaximal cyclic test conditions. MATERIALS AND METHODS: Eighteen human cadaveric menisci were divided into three groups of six specimens. A scalpel was used to create a 2 cm lesion at 3 mm from the outer edge of the posterior third of each specimen. Merselene tape loops were placed around each side of the lesion and the tears were repaired using two vertical FasT-Fix, two horizontal FasT-Fix, or two RapidLoc devices. Cyclic testing (5-50 N at 1 Hz for 500 cycles) was performed on a servo hydraulic device. One-way ANOVA and Scheffe post-hoc tests were used to evaluate group differences (P < 0.05). RESULTS: The vertical FasT-Fix group had less displacement over the initial ten loading cycles compared to the RapidLoc group (P = 0.004), but did not differ from the horizontal FasT-Fix group (P = 0.07). At 50, 100, 200, 300, 400, and 500 cycles, the vertical FasT-Fix group had less displacement than the horizontal FasT-Fix or RapidLoc groups (P < or = 0.004). At each interval the vertical FasT-Fix group had greater relative stiffness than the other groups (P < or = 0.009). CONCLUSIONS: The vertical FasT-Fix group had comparatively less displacement (primarily repair site gapping) and greater relative stiffness.

Biomechanical comparison between CentraLoc and Intrafix fixation of quadrupled semitendinosus-gracilis allografts in cadaveric tibiae with low bone mineral density.

Supplementary or back-up tibial tunnel fixation of a quadruple semitendinosus-gracilis (STG) graft is often performed when the knee surgeon questions the integrity of intra-tunnel fixation. Back-up fixation devices such as staples however may contribute to increased knee pain and dysfunction. Both primary extra-tunnel and intra-tunnel fixation devices may provide sufficient quadruple STG graft fixation in a tibial tunnel to preclude the need for back-up fixation. This biomechanical study compared the fixation of quadruple STG allografts in standard drilled tunnels prepared in low apparent bone mineral density (BMD) cadaveric tibiae using either an Intrafix device with primary intra-tunnel fixation in a region of predominantly cancellous trabecular bone, or a CentraLoc device with primary extra-tunnel fixation in a region of predominantly cortical bone. The study hypothesis was that the CentraLoc device would display superior fixation in these low apparent BMD cadaveric tibiae. Matched pair tibiae and quadruple STG allografts were divided into two groups of seven specimens each. Extraction drilled tunnels matched allograft diameter. Constructs were pretensioned on a servo hydraulic device between 10 and 50 N for 10 cycles and isometric pretensioned at 50 N for 1 min prior to undergoing 500 loading cycles (50-250 N) and load to failure testing (20 mm/min). The CentraLoc group displayed superior load at failure (448.4+/-171 N vs. 338.4+/-119 N, P=0.04) and survived more loading cycles (410+/-154 cycles vs. 196+/-230 cycles, P=0.04) than the Intrafix group. Most CentraLoc group specimens (6/7, 85.7%) failed by device pullout with intact quadruple STG allograft strands while all Intrafix group specimens (7/7, 100%) failed by slippage of one or more strands (P=0.005).

Scapulothoracic latent muscle reaction timing comparison between trained overhead throwers and untrained control subjects.

AIM: This study evaluated select scapulothoracic muscles for training-induced latent muscle reaction timing (LMRT) changes. Comparisons were also made between the dominant and non-dominant upper extremities and between individual muscles. MATERIALS AND METHODS: Fifteen male trained overhead throwers (college baseball pitchers) and 15 male untrained, age-matched control subjects participated in this study. Scapulothoracic muscle activation data were collected as subjects attempted to stop a variably timed, sudden glenohumeral joint internal rotation perturbation. RESULTS: Training group differences were not evident for LMRT (P=0.56), however upper extremity dominance (P=0.003) and test muscle (P=0.0002) displayed significant differences. Dominant upper extremity upper trapezius muscle LMRT (72.5+/-26 ms) occurred later than non-dominant upper trapezius muscle LMRT (60.0+/-14.1 ms, P=0.001). Dominant upper extremity middle trapezius-rhomboid muscle LMRT (60.0+/-16.2 ms) occurred later than non-dominant middle trapezius-rhomboid muscle LMRT (50.2+/-12.6 ms, P=0.004). Dominant upper extremity upper trapezius muscle LMRT also occurred later than serratus anterior (55.7+/-16.0 ms, P=0.001) and middle trapezius-rhomboid LMRT (60.2+/-16 ms, P=0.003). Mean overall dominant upper extremity LMRT (62.7+/-19.4 ms) was delayed compared with mean overall non-dominant upper extremity LMRT (53.9+/-12.4 ms, P=0.003). CLINICAL CONSEQUENCES: Although training was not found to influence scapulothoracic LMRT, differences were observed between the dominant and non-dominant upper extremities. Consistent LMRT delays at the dominant upper extremity suggest possible neuromuscular timing differences to enable prolonged glenohumeral joint and scapulothoracic articulation acceleration before deceleration through eccentric muscle activation. Both trained and untrained overhead throwers displayed this response. Variable perturbation test velocities, and in-season testing of larger subject groups may be needed to better elucidate the more subtle differences associated with training.

Shoulder and elbow function 2 years following long head triceps interposition flap transfer for massive rotator cuff tear reconstruction.

INTRODUCTION: Patient outcomes were determined at a minimum of 2 years following massive rotator cuff tear ( > or = 5 cm(2)) reconstruction using a triceps brachii long head interposition flap. A physiotherapist at an independent clinic performed all measurements. PATIENTS AND METHODS: Of 24 total eligible patients, 19 completed pre-operative and follow-up UCLA Shoulder Scores and ASES Function Scores. Of these 19 patients, 14 who did not have co-morbidities that negatively impacted their ability to perform intense exercise underwent a comprehensive clinical examination of involved and uninvolved side shoulder and elbow active range of motion and strength (both isometric instrumented manual muscle testing and concentric isokinetic measurements). RESULTS: At 2 years following surgery, pre-operative UCLA Shoulder Scores improved from 10.6 +/- 3 to 27.4 +/- 5 and pre-operative ASES Function Scores improved from 20.1 +/- 10 to 43.2 +/- 5. However, isometric involved side shoulder abductor torque was decreased by 28.2% with instrumented manual muscle testing, and concentric shoulder external rotator torque was decreased by 44.6% at 60 degrees/s and by 53.8% at 120 degrees/s with isokinetic testing. Isometric involved side elbow extensor torque was decreased by 39% with instrumented manual muscle testing, and concentric elbow extensor torque was decreased by 17.7% and 19.2% at 60 and 120 degrees/s, respectively, with isokinetic testing. Including three additional patients who were contacted via telephone, the majority of patients (21 of 22, 95.4%) were satisfied with their improved shoulder function and reduced pain. CONCLUSIONS: Despite reduced pain and improved shoulder function, residual involved side shoulder abductor; shoulder external rotator and elbow extensor strength deficits were evident at 2 years following surgery. This suggests the need for more focused rehabilitation, particularly for involved side elbow extensor strengthening to further improve patient function and minimize disability.

In vitro HgCl2 exposure of immune cells at different stages of maturation: effects on phenotype and function.

This is the first study to investigate the hypothesis that the immunotoxic effects of inorganic mercury may be modulated by inherent differences in the responsiveness of immune cells related to the age of the donor. We exposed cells from lymph nodes, spleen, and thymus, collected from 7- and 10-day-old CD.1 pups, as well as from adult CD.1 mice, in terms of the effects of mercury in vitro on responses to Con-A stimulation with respect to proliferation, cytokine production, and cell phenotype. The effects of mercury on proliferation were age and organ dependent, while effects on cytokine production were only age dependent. Effects of mercury were observed only on splenocyte T-cell subpopulations and only in cells from 10-day-old pups and from adults. Mercury had no effect on IFN-gamma and IL-4 production by splenocytes from 7-day-old pups, but significantly decreased release of these cytokines by splenocytes from 10-day-old pups and adults. Hg did not affect IL-4 production by lymph node cells or thymocytes. In lymph node cells Hg affected IFN-gamma production only at 7 days. These data indicate that inherent properties of immune cells at different stages of development may influence the response to immunotoxicants.

Femoral anteversion influences vastus medialis and gluteus medius EMG amplitude: composite hip abductor EMG amplitude ratios during isometric combined hip abduction-external rotation.

This prospective study evaluated differences in vastus medialis (VM) and gluteus medius (GM) EMG amplitude:composite hip abductor (gluteus maximus, gluteus medius, tensor fascia lata) EMG amplitude ratios among subjects with low or high relative femoral anteversion. Data were collected during the performance of a non-weight bearing, non-sagittal plane maximal volitional effort isometric combined hip abduction-external rotation maneuver. Eighteen nonimpaired athletically active females participated in this surface EMG study. Medial hip rotation (relative femoral anteversion estimate) was measured with a handheld goniometer. Subjects were grouped by medial hip rotation displacement (group 1 < or = 42 degrees =36.1+/-7 degrees and group 2 > 42 degrees =52.7+/-7 degrees ) for statistical analysis (Mann Whitney U-tests, p < 0.05). Group 2 had decreased VM (42+/-23% vs. 69+/-30%, U=19, p=0.034) and GM (62+/-25% vs. 96+/-39%, U=19, p=0.034) normalized mean peak EMG amplitude:composite mean peak hip abductor EMG amplitude ratios compared to group 1. Decreased normalized VM (-27%) and GM (-34%) EMG amplitudes among subjects with increased relative femoral anteversion suggest reduced dynamic frontal and transverse plane femoral control from these muscles, possibly contributing to the increased incidence of non-contact knee injury observed among athletic females.

Physiological coxa varus-genu valgus influences internal knee and ankle joint moments in females during crossover cutting.

This study evaluated the ankle and knee electromyographic, kinematic, and kinetic differences of 20 nonimpaired females with either neutral (group 1) or coxa varus-genu valgus (group 2) alignment during crossover cutting stance phase. Two-way mixed model ANOVA (group, session) assessed mean differences ( p<0.05) and correlation analysis further delineated relationships. During impact absorption, group 2 displayed earlier peak horizontal braking (anterior-posterior) ground reaction force timing, decreased and earlier peak internal knee extension moments (eccentric function), and earlier peak internal ankle dorsiflexion moment timing (eccentric function). During the pivot phase, group 2 displayed later and eccentrically-biased peak ankle plantar flexion moments, increased peak internal knee flexion moments (eccentric function), and later peak knee internal rotation timing. Correlation analysis revealed that during impact absorption, subjects with coxa varus-genu valgus alignment (group 2) displayed a stronger relationship between knee internal rotation velocity and peak internal ankle dorsiflexion moment onset timing ( r= -0.64 vs r = -0.26) and between peak horizontal braking ground reaction forces and peak internal ankle dorsiflexion moment onset timing ( r= 0.61 vs r= 0.24). During the pivot phase these subjects displayed a stronger relationship between peak horizontal braking ground reaction forces and peak internal ankle plantar flexion moment onset timing ( r= -0.63 vs r= -0.09) and between peak horizontal braking forces and peak internal ankle plantar flexion moments ( r= -0.72 vs r= -0.26). Group differences suggest that subjects with coxa varus-genu valgus frontal-plane alignment have an increased dependence on both ankle dorsiflexor and plantar flexor muscle group function during crossover cutting. Greater dependence on ankle muscle group function during the performance of a task that requires considerable 3D dynamic knee joint control suggests a greater need for frontal and transverse plane weight bearing tasks that facilitate eccentric ankle muscle group function to optimize injury prevention conditioning and post-surgical rehabilitation programs.

Tibial fixation comparison of semitendinosus-bone composite allografts fixed with bioabsorbable screws and bone-patella tendon-bone grafts fixed with titanium screws.

Tibial fixation remains the weak link of ACL reconstruction over the first 8-12 weeks postoperatively. This study compared the biomechanical properties of tibial fixation for a bone-patellar tendon-bone (BPTB) graft and a novel semitendinosus-bone composite (SBC) allograft with mixed cortical-cancellous bone dowels at each end. Seven paired, fresh frozen cadaveric knees (20-45 years) were stripped of all soft tissue attachments and randomly assigned to receive either the BPTB graft or SBC allograft. Grafts were placed into tibial tunnels via a standard protocol and secured with either a 10 mmx28 mm bioabsorbable (SBC) or titanium (BPTB) screw. Grafts were cycled ten times in a servo hydraulic device from 10-50 N prior to pull to failure testing at a rate of 20 mm/min with the force vector aligned with the tibial tunnel ("worst case scenario"). Wilcoxon Signed Rank Tests were used to evaluate biomechanical differences between graft types ( p<0.05). Tibial bone mineral density and interference screw insertion torque were statistically equivalent between graft types. The mode of failure for all constructs was direct screw and graft construct pullout from the tibial tunnel. Significant differences were not observed between graft types for maximum load at failure strength (BPTB=620.8+/-209 N vs. SBC=601.2+/-140 N, p=0.74) or stiffness (BPTB=69.8 N/mm+/-29 N/mm vs SBC=47.1+/-31.6 N/mm, p=0.24). The SBC allograft yielded significantly more displacement prior to failure than the BPTB graft (15.1+/-4.9 mm vs 9.2+/-1.3 mm, p=0.04). Increased construct displacement appeared to be due to fixation failure, with some evidence of graft tissue tearing around the sutures: Bioabsorbable screw (10 x 28 mm) fixation of the SBC allograft produced unacceptable displacement levels during testing. Further study is recommended using a titanium interference screw or a longer bioabsorbable screw for SBC graft fixation under cyclic loading conditions.