Pelvic Tilt in Adults With Cerebral Palsy and Its Relationship With Prior Hamstrings Lengthening.

BACKGROUND: Current studies assessing the change in pelvic tilt for ambulatory patients with cerebral palsy (CP) after surgical hamstring lengthening (SHL) lack a comparison cohort without prior SHL and are limited to younger patients. This study presents gait data of middle-aged adults with CP, primarily focusing on the pelvis, and compares pelvic tilt, trunk tilt, and knee flexion between those with and without prior SHL. MATERIALS AND METHODS: A consecutive series of 54 adults with CP, a mean age of 36±13 years, and Gross Motor Function Classification System (GMFCS) levels I-III were included. Thirty-two (59%) had SHL performed at a mean age of 8±5 years. Three-dimensional gait analysis data prospectively collected at a mean of 28±14 years postoperatively were retrospectively analyzed. Chi-square tests were used to compare demographic and surgical history data and statistical parameter mapping was used to compare knee flexion during stance and pelvic and trunk tilts during the gait cycle between SHL and SHL-naive groups. RESULTS: Age, GMFCS level, sex, race, topography, and ethnicity were not different between the groups (P=.217-.612). Anterior pelvic tilt throughout gait was significantly greater in the SHL group compared with the SHL-naive group (63%-87%; P=.033). This difference was augmented after accounting for other surgical history and revision SHL (0%-32%, P=.019; and 46%-93%, P=.007). CONCLUSION: Within a cohort of adults with CP, GMFCS levels I-III, and a mean age of 36 years, those with a history of SHL, performed a mean of 28 years prior to 3-dimensional gait analysis, walked with increased anterior pelvic tilt compared with those without a history of SHL. [Orthopedics. 202x;4x(x):xx-xx.].

Body mass affects kinetic symmetry and inflammatory markers in adolescent knees during gait.

BACKGROUND: Early-onset osteoarthritis has been attributed to pro-inflammatory factors and biomechanical changes in obesity. However, research has yet to explore whether knee joint moments are asymmetrical in children with obesity and could precede the onset of knee osteoarthritis. The present study compares knee moment asymmetry between adolescents with and without obesity and examines the relationship between asymmetries and inflammatory biomarkers. METHODS: Twenty-eight adolescents (13-16 years) were classified as with (n = 12) or without (n = 16) obesity. Lower extremity kinetics were measured using three-dimensional motion analysis. Bilateral knee joint moments were analyzed in the sagittal, frontal, and transverse planes across stance phase. Kinetic asymmetry was calculated between the right and left sides and represented by the R2 value. Enzyme-linked immunosorbent assays analyzed serum 25-hydroxy vitamin D, interferon gamma, tumor nercrosis factor alpha, interleukin-6, and C-reactive protein levels. Parametric and non-parametric tests determined significant group differences in asymmetries and biomarkers, respectively. Spearman's correlations identified relationships between biomarkers and asymmetries with statistically significant group differences. FINDINGS: Adolescents with obesity had greater sagittal (loading, midstance) and frontal (midstance, pre-swing) plane kinetic knee asymmetry and higher concentrations of interleukin-6 and C-reactive protein. A moderately negative correlation existed between C-reactive protein and sagittal (loading, midstance) plane asymmetry, and also between interleukin-6 and frontal (pre-swing) plane asymmetry. INTERPRETATION: Inflammatory response increases with greater knee joint asymmetry, suggesting knee joint damage and altered joint loading co-exist in adolescents with obesity. Increased risk to joint health may exist in sub-phases where knee joints are improperly loaded.

Dynamic Assessment of Femoroacetabular Impingement Syndrome Hips.

PURPOSE: The purpose of our study was to compare lower extremity rotational kinematics and kinetics (angles, torques, and powers) and hip muscle electromyography (EMG) activity between cam-type femoroacetabular impingement syndrome (FAIS) and age- and sex-matched controls during walking, fast walking, stair ascent, stair descent, and sit-to-stand. METHODS: This study included 10 males with unilateral FAIS and 10 control males with no FAIS. We measured kinematics, kinetics, and electromyographic signals during stair ascent/descent, sit-to-stand, self-selected walk, and fast walk. Peak signal differences between groups were compared with independent t-tests with statistical significance when P < .05. RESULTS: FAIS hips showed significant differences compared to controls, including increased hip flexion during walking (+4.9°, P = .048) and stair ascent (+7.8°, P =.003); diminished trunk rotation during stair ascent (-3.4°; P = .015), increased knee flexion during self-selected walking (+5.1°, P = .009), stair ascent (+7.4°, P = .001), and descent (+5.3°, P = .038); and increased knee valgus during fast walking (+4.7°, P = .038). gMed and MedHam showed significantly decreased activation in FAIS during walking (gMed: -12.9%, P = .002; MedHam: -7.4%, P = .028) and stair ascent (gMed: -16.7%, P = .036; MedHam: -13.0%, P = .041); decreased gMed activation during sit-to-stand (-8.8%, P = .004) and decreased MedHam activation during stair descent (-8.0%, P = .039). CONCLUSIONS: Three-dimensional motion analysis and EMG evaluation of functional kinematics and kinetics in subjects with symptomatic unilateral cam-type FAIS across a spectrum of provocative tasks demonstrated significant differences compared to controls in hip flexion, trunk rotation, knee flexion, and valgus. FAIS hips had significantly decreased gMed and MedHam activity. These findings may explain altered torso-pelvic, hip, and knee mechanics in FAIS patients and suggest that evaluation of FAIS should include the patient's hip, knee, and torso-pelvic relationships and muscle function. CLINICAL RELEVANCE: The clinical and functional manifestation of FAIS hip pathomechanics is not entirely understood, and previous literature to date has not clearly described the alterations in gait and functional movements seen in patients with cam-type FAIS. The current study used 3D motion analysis and EMG evaluation of functional kinematics and kinetics to identify a number of differences between FAIS and control hips, which help us better understand the lower extremity kinematics and kinetics and muscle activation in FAIS.

Differences in Gait and Stair Ascent After Total Ankle Arthroplasty and Ankle Arthrodesis.

BACKGROUND: Ankle arthrodesis has historically been the standard of care for end-stage ankle arthritis; however, total ankle arthroplasty (TAA) is considered a reliable alternative. Our objective was to compare 3-dimensional foot and ankle kinetics and kinematics and determine the ankle power that is generated during level walking and stair ascent between TAA and ankle arthrodesis patients. METHODS: Ten patients who underwent TAA with a modern fixed-bearing ankle prosthesis and 10 patients who previously underwent ankle arthrodesis were recruited. Patients were matched for age, sex, body mass index, time from surgery, and preoperative diagnosis. A minimum of 2-year follow-up was required. Patients completed instrumented 3D motion analysis while walking over level ground and during stair ascent. Between-group differences were assessed with a 2-tailed Mann-Whitney exact test for 2 independent samples. RESULTS: Sagittal ankle range of motion (ROM) was significantly higher in the TAA group (21.1 vs 14.7 degrees, P = .003) during level walking. In addition, forefoot-tibia motion (25.3±5.9 degrees vs 18.6±5.1 degrees, P = .015) and hindfoot-tibia motion (15.4±3.2 degrees vs 12.2±2.5 degrees, P = .022) were significantly greater in the TAA group. During stair ascent, sagittal ankle ROM (25 vs 17.1 degrees, P = .026), forefoot-tibia motion (27.6 vs 19.6 degrees, P = .017), and hindfoot-tibia motion (16.8 vs 12 degrees, P = .012) was greater. CONCLUSION: There were significant differences during level walking and stair ascent between patients with TAA and ankle arthrodesis. TAA patients generated greater peak plantarflexion power and sagittal motion within the foot and ankle compared to patients with an ankle arthrodesis. Further investigation should continue to assess biomechanical differences in the foot and ankle during additional activities of daily living. LEVEL OF EVIDENCE: Level III, comparative study.

Changes in Lower Extremity Kinematics and Temporal Parameters of Adolescent Baseball Pitchers During an Extended Pitching Bout.

BACKGROUND: Few studies have investigated detailed 3-dimensional lower extremity kinematics during baseball pitching in adolescent athletes during extended play. Changes in these parameters may affect performance outcomes. PURPOSE: To investigate whether adolescent baseball pitchers experience changes in lower extremity kinematics and event timing during a simulated game-length pitching bout. STUDY DESIGN: Descriptive laboratory study. METHODS: Twelve male adolescent pitchers (aged 14-16 years) threw 6 sets of 15 fastball pitches from an artificial pitching mound to a target at regulation distance. Joint angles and angular velocities at the hip, knee, and ankle of both legs were collected throughout the phases of the pitching cycle as well as stride length, pelvis orientation, pitch duration, timing of foot contact and ball release, ball speed, and pitching accuracy. Paired t tests ( P < .05) were used to compare the dependent variables between the last 5 pitches of the second (baseline) and sixth (final) sets. RESULTS: During the stride phase, decreased maximum angular excursions for hip extension (baseline: 14.7° ± 9.8°; final: 11.6° ± 10.3°; P < .05) and ankle plantar flexion (baseline: 30.2° ± 14.5°; final: 24.2° ± 15.3°; P < .05) as well as maximum angular velocity for knee extension (baseline: 144.9 ± 63.3 deg·s-1; final: 121.7 ± 62.0 deg·s-1; P < .05) were observed between sets in the trailing leg. At foot contact, pitchers had decreased hip flexion (baseline: 69.5° ± 10.1°; final: 66.5° ± 11.8°; P < .05) and increased hip abduction (baseline: 20.7° ± 8.9°; final: 25.4° ± 6.0°; P < .05) in the leading leg in the final set. Compared with the baseline set, ball speed significantly decreased in the final set (29.5 ± 2.5 m·s-1 vs 28.3 ± 2.5 m·s-1, respectively; P < .05). CONCLUSION: Kinematic changes and decreased ball speeds observed in the final set suggest that adolescent pitchers are unable to maintain lower extremity kinematics and performance as a result of extended play. CLINICAL RELEVANCE: The results from this study may warrant further investigation into how altered lower extremity kinematics may affect trunk and upper extremity function, performance, and risk of injuries during pitching in adolescent athletes, particularly during actual game play.

An Investigation of Structure, Flexibility, and Function Variables that Discriminate Asymptomatic Foot Types.

It has been suggested that foot type considers not only foot structure (high, normal, low arch), but also function (overpronation, normal, oversupination) and flexibility (reduced, normal, excessive). Therefore, this study used canonical regression analyses to assess which variables of foot structure, function, and flexibility can accurately discriminate between clinical foot type classifications. The feet of 61 asymptomatic, healthy adults (18-77 years) were classified as cavus (N = 24), rectus (N = 54), or planus (N = 44) using standard clinical measures. Custom jigs assessed foot structure and flexibility. Foot function was assessed using an emed-x plantar pressure measuring device. Canonical regression analyses were applied separately to extract essential structure, flexibility, and function variables. A third canonical regression analysis was performed on the extracted variables to identify a combined model. The initial combined model included 30 extracted variables; however 5 terminal variables (malleolar valgus index, arch height index while sitting, first metatarsophalangeal joint laxity while standing, pressure-time integral and maximum contact area of medial arch) were able to correctly predict 80.7% of foot types. These remaining variables focused on specific foot characteristics (hindfoot alignment, arch height, midfoot mechanics, Windlass mechanism) that could be essential to discriminating foot type.

Surgical Treatments for Scapholunate Advanced Collapse Wrist: Kinematics and Functional Performance.

PURPOSE: The purpose of this investigation was to compare kinematic motion and functional performance during 2 tasks in patients following 4-corner fusion (4CF) or proximal row carpectomy (PRC) and to compare these data with those from healthy asymptomatic individuals. METHODS: Twenty men (10 4CFs and 10 PRCs, ages, 43-82 y) were recruited for 3-dimensional wrist motion analysis testing. Kinematic coupling (the ratio of wrist flexion/extension to radial-ulnar deviation), kinematic path length (a measure of total angle distance), clinical measures, and performance measures were collected during 2 tasks: dart throwing and hammering. For each outcome, between-group comparisons employed a 1-way analysis of variance with post hoc analysis using the Fisher least significant difference test. RESULTS: All clinical measures (flexion-extension, radial-ulnar deviation, and grip strength) were decreased for 4CF and PRC patients compared with healthy subjects. Coupling, kinematic path length, and performance were all significantly reduced in 4CF and PRC patients compared with healthy subjects during both tasks. Reduced coupling and a shorter kinematic path length are indicative of less global and combined wrist motion. There were no differences identified in coupling patterns or performance between the surgical groups for the dart-throwing task. However, in hammering, the kinematic path length and performance (time and total strikes) were worse in 4CF than in PRC. CONCLUSIONS: Differences in wrist kinematics and performance were identified between the groups. PRC subjects performed better on kinematic and performance variables. As expected, both groups demonstrated decreased wrist kinematic motion and functional performance compared with individuals with normal wrists. These results require confirmation and while they cannot be used to determine the benefits of one procedure over the other, they are an important step in quantifying differences in motion and function between procedures. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic II.

The functional effect of a distal rectus femoris tenotomy in adults with cerebral palsy.

The purpose of this study was to determine the effect of a distal rectus femoris tenotomy on function and gait in adults with cerebral palsy who had diminished knee flexion during swing. A stiff knee gait pattern is commonly seen in individuals with cerebral palsy and frequently leads to tripping and falling. Five subjects, 25-51 years, (34.6±10.3 years) participated in the study; each individual had the surgery after the age of 18. Four of the five subjects underwent bilateral distal rectus femoris tenotomies for a total of nine limbs being studied. Four of the five subjects had a single procedure of a distal rectus femoris tenotomy and one subject also had bilateral adductor tenotomies. All individuals underwent a pre-operative and post-operative, (3.28±1.6 years) three-dimensional gait analysis. Pre-operative gait revealed diminished peak knee flexion and out of phase rectus femoris activity with a quiet vastus lateralis during swing in all subjects. Significant findings after a distal rectus femoris tenotomy included: improved peak swing knee flexion, improved peak stance hip extension, and increased total knee excursion without loss in knee extension strength. During swing, knee flexion angle improved on average 11° which correlated with subjective report of less shoe wear, tripping, and falling due to improved clearance. In conclusion, a distal rectus femoris tenotomy should be considered a surgical option for adults with cerebral palsy and a stiff knee gait pattern to improve mobility, function, and quality of life.

Development of an anatomical wrist joint coordinate system to quantify motion during functional tasks.

The purpose of this study was to develop a three-dimensional (3D) motion analysis based anatomical wrist joint coordinate system for measurement of in-vivo wrist kinematics. The convergent validity and reliability of the 3D motion analysis implementation was quantified and compared with manual and electrogoniometry techniques on 10 cadaveric specimens. Fluoroscopic measurements were used as the reference. The 3D motion analysis measurements (mean absolute difference [MAD] = 3.6°) were significantly less different (P < .005) than manual goniometry (MAD = 5.7°) but not (P = .066, power = 0.45) electrogoniometry (MAD = 5.0°) compared with fluoroscopy. The intraclass correlation coefficient (ICC[2,1]) was highest for 3D motion analysis compared with manual and electrogoniometry, suggesting better reliability for this technique. To demonstrate the utility of this new wrist joint coordinate system, normative data from 10 healthy subjects was obtained while throwing a dart.

Wrist kinematic coupling and performance during functional tasks: effects of constrained motion.

PURPOSE: To quantify the coupled motion of the wrist during selected functional tasks and to determine the effects of constraining this coupled motion using a radial-ulnar deviation blocking splint on performance of these tasks. METHODS: Ten healthy, right-handed men performed 15 trials during selected functional tasks with and without a splint, blocking radial and ulnar deviation. The following tasks were performed: dart throwing, hammering, basketball free-throw, overhand baseball and football throwing, clubbing, and pouring. Kinematic coupling parameters (coupling, kinematic path length, flexion-extension range of motion, radial-ulnar deviation range of motion, flexion-extension offset, and radial-ulnar deviation offset) and performance were determined for each functional task. A generalized estimation equation model was used to determine whether each kinematic coupling parameter was significantly different across tasks. A repeated-measures generalized estimation equation model was used to test for differences in performance and kinematic coupling parameters between the free and splinted conditions. RESULTS: Wrist motion exhibited linear coupling between flexion-extension and radial-ulnar deviation, demonstrated by R(2) values from 0.70 to 0.99. Average wrist coupling and kinematic path lengths were significantly different among tasks. Coupling means and kinematic path lengths were different between free and splinted conditions across all tasks other than pouring. Performance was different between wrist conditions for dart throwing, hammering, basketball shooting, and pouring. CONCLUSIONS: Wrist kinematic coupling parameters are task specific in healthy individuals. Functional performance is decreased when wrist coupling is constrained by an external splint. CLINICAL RELEVANCE: Surgical procedures that restrict wrist coupling may have a detrimental effect on functional performance as defined in the study. Patients may benefit from surgical reconstructive procedures and wrist rehabilitation protocols designed to restore kinematic coupling.

Effect of shoe flexibility on plantar loading in children learning to walk.

BACKGROUND: In a previous pilot study of "cruisers" (nonindependent ambulation), "early walkers" (independent ambulation for 0-5 months), and "experienced walkers" (independent ambulation for 6-12 months), developmental age significantly affected the children's stability when walking and performing functional activities. We sought to examine how shoe structural characteristics affect plantar pressure distribution in early walkers. METHODS: Torsional flexibility was evaluated in four shoe designs (UltraFlex, MedFlex, LowFlex, and Stiff based on decreasing relative flexibility) with a structural testing machine. Plantar pressures were recorded in 25 early walkers while barefoot and shod at self-selected walking speeds. Peak pressure was calculated over ten masked regions for the barefoot and shod conditions. RESULTS: Torsional flexibility, the angular rotation divided by the applied moment about the long axis of the shoe, was different across the four shoe designs. As expected, UltraFlex was the most flexible and Stiff was the least flexible. As applied moment increased, torsional flexibility decreased in all footwear. When evaluating early walkers during gait, peak pressure was significantly different across shoe conditions for all of the masked regions. The stiffest shoe had the lowest peak pressures and the most flexible shoe had the highest. CONCLUSIONS: It is likely that increased shoe flexibility promoted greater plantar loading. Plantar pressures while wearing the most flexible shoe are similar to those while barefoot. This mechanical feedback may enhance proprioception, which is a desirable attribute for children learning to walk.

Foot Type Biomechanics Part 2: are structure and anthropometrics related to function?

BACKGROUND: Many foot pathologies are associated with specific foot types. If foot structure and function are related, measurement of either could assist with differential diagnosis of pedal pathologies. HYPOTHESIS: Biomechanical measures of foot structure and function are related in asymptomatic healthy individuals. METHODS: Sixty-one healthy subjects' left feet were stratified into cavus (n=12), rectus (n=27) and planus (n=22) foot types. Foot structure was assessed by malleolar valgus index, arch height index, and arch height flexibility. Anthropometrics (height and weight), age, and walking speed were measured. Foot function was assessed by center of pressure excursion index, peak plantar pressure, maximum force, and gait pattern parameters. Foot structure and anthropometric variables were entered into stepwise linear regression models to identify predictors of function. RESULTS: Measures of foot structure and anthropometrics explained 10-37% of the model variance (adjusted R(2)) for gait pattern parameters. When walking speed was included, the adjusted R(2) increased to 45-77% but foot structure was no longer a factor. Foot structure and anthropometrics predicted 7-47% of the model variance for plantar pressure and 16-64% for maximum force parameters. All multivariate models were significant (p<0.05), supporting acceptance of the hypothesis. DISCUSSION AND CONCLUSION: Foot structure and function are related in asymptomatic healthy individuals. The structural parameters employed are basic measurements that do not require ionizing radiation and could be used in a clinical setting. Further research is needed to identify additional predictive parameters (plantar soft tissue characteristics, skeletal alignment, and neuromuscular control) and to include individuals with pathology.

The effect of foot structure on 1st metatarsophalangeal joint flexibility and hallucal loading.

The purpose of our study was to examine 1st metatarsophalangeal (MTP) joint motion and flexibility and plantar loads in individuals with high, normal and low arch foot structures. Asymptomatic individuals (n=61), with high, normal and low arches participated in this study. Foot structure was quantified using malleolar valgus index (MVI) and arch height index (AHI). First MTP joint flexibility was measured using a specially constructed jig. Peak pressure under the hallux, 1st and 2nd metatarsals during walking was assessed using a pedobarograph. A one-way ANOVA with Bonferroni-adjusted post hoc comparisons was used to assess between-group differences in MVI, AHI, early and late 1st MTP joint flexibility in sitting and standing, peak dorsiflexion (DF), and peak pressure under the hallux, 1st and 2nd metatarsals. Stepwise linear regression was used to identify predictors of hallucal loading. Significant between-group differences were found in MVI (F(2,56)=15.4, p<0.01), 1st MTP late flexibility in sitting (F(2,57)=3.7, p=0.03), and standing (F(2,57)=3.7, p=0.03). Post hoc comparisons demonstrated that 1st MTP late flexibility in sitting was significantly higher in individuals with low arch compared to high arch structure, and that 1st MTP late flexibility in standing was significantly higher in individuals with low arch compared to normal arch structure. Stepwise regression analysis indicated that MVI and 1st MTP joint early flexibility in sitting explain about 20% of the variance in hallucal peak pressure. Our results provide objective evidence indicating that individuals with low arches show increased 1st MTP joint late flexibility compared to individuals with normal arch structure, and that hindfoot alignment and 1st MTP joint flexibility affect hallucal loading.

A spectral analysis of rotator cuff musculature electromyographic activity: surface and indwelling.

Electromyography (EMG) of the shoulder girdle is commonly performed; however, EMG spectral properties of shoulder muscles have not been clearly defined. The purpose of this study was to determine the maximum power frequency, Nyquist rate, and minimum sampling rate for indwelling and surface EMG of the normal shoulder girdle musculature. EMG signals were recorded using indwelling electrodes for the rotator cuff muscles and surface electrodes for ten additional shoulder muscles in ten healthy volunteers. A fast Fourier transform was performed on the raw EMG signal collected during maximal isometric contractions to derive the power spectral density. The 95% power frequency was calculated during the ramp and plateau subphase of each contraction. Data were analyzed with analysis of variance (ANOVA) and paired t tests. Indwelling EMG signals had more than twice the frequency content of surface EMG signals (p < .001). Mean 95% power frequencies ranged from 495 to 560 Hz for indwelling electrodes and from 152 to 260 Hz for surface electrodes. Significant differences in the mean 95% power frequencies existed among muscles monitored with surface electrodes (p = .002), but not among muscles monitored with indwelling electrodes (p = .961). No significant differences in the 95% power frequencies existed among contraction subphases for any of the muscle-electrode combinations. Maximum Nyquist rate was 893 Hz for surface electrodes and 1,764 Hz for indwelling electrodes. Our results suggest that when recording EMG of shoulder muscles, the minimum sampling frequency is 1,340 Hz for surface electrodes and 2,650 Hz for indwelling electrodes. The minimum sampling recommendations are higher than the 1,000 Hz reported in many studies involving EMG of the shoulder.

Differences between sexes in lower extremity alignment and muscle activation during soccer kick.

BACKGROUND: Injury risk in soccer varies by sex. Female soccer players face a greater risk of anterior cruciate ligament injury and patellofemoral problems, while male players are more likely to experience sports hernia symptoms. The purpose of this study was to test the hypothesis that females have different lower-extremity alignment and muscle activation patterns than males during the soccer kick. METHODS: Thirteen male and twelve female college soccer players underwent three-dimensional motion analysis and electromyography of seven muscles (iliacus, gluteus maximus, gluteus medius, vastus lateralis, vastus medialis, hamstrings, and gastrocnemius) in both the kicking and the supporting lower extremity and two additional muscles (hip adductors and tibialis anterior) in the kicking limb only. Five instep and five side-foot kicks were recorded for each player. Muscle activation was recorded as a percentage of maximum voluntary isometric contraction. RESULTS: The male soccer players had significantly higher mean muscle activation than their female counterparts with respect to the iliacus in the kicking limb (123% compared with 34% of maximal voluntary isometric contraction; p = 0.0007) and the gluteus medius (124% compared with 55%; p = 0.005) and vastus medialis muscles (139% compared with 69%; p = 0.002) in the supporting limb. The supporting limb reached significantly greater mean hip adduction during the stance phase of the kick in the females compared with that in the males (15 degrees and 10 degrees, respectively; p = 0.006). CONCLUSIONS: Differences between the sexes in lower extremity alignment and muscle activation occur during the soccer instep and side-foot kicks. Decreased activation of the hip abductors and greater hip adduction in the supporting limb during the soccer kick in female athletes may be associated with their increased risk for anterior cruciate ligament injury.

Mini-midvastus vs standard medial parapatellar approach: a prospective, randomized, double-blinded study in patients undergoing bilateral total knee arthroplasty.

The purpose of this study was to determine whether the mini-midvastus approach to total knee arthroplasty (TKA) results in differences in quadriceps muscle strength as well as previously cited advantages in a double blind prospective randomized trial. Twenty-seven patients (54 TKAs) scheduled for bilateral TKA were randomized to undergo mini-midvastus approach on one knee and standard approach on the other. Incision lengths were the same. Postoperative strength was determined by isokinetic and isometric peak torque testing. Range of motion, pain Visual analog scale, side-preference, and gait analysis were assessed preoperatively and postoperatively. The only significant difference in strength testing was increased isokinetic and isometric extension torque at 3 weeks postoperatively for the mini-midvastus approach. No differences between the mini-midvastus and standard approach were observed for stride length, stance time, pain Visual analog scale, or knee range of motion. The mini-midvastus approach has limited benefit compared to the standard approach for TKA.

Subacromial injection improves deltoid firing in subjects with large rotator cuff tears.

Previous studies demonstrate that scapulohumeral mechanics improve after subacromial injection. However, it is unclear how injection affects muscle firing. Forty-one subjects with two-tendon rotator cuff tears and 23 volunteer subjects with normal rotator cuffs documented by ultrasonography were examined. Electromyographic activity from 12 muscles was collected during ten functional tasks. Nine symptomatic subjects with rotator cuff tears underwent subacromial injection of anesthetic and underwent repeat electromyographic examination. Subjects with rotator cuff tears demonstrate global electromyographic differences when compared to normal controls. Asymptomatic subjects with rotator cuff tears had significantly increased anterior deltoid firing when compared to symptomatic counterparts during forward shoulder elevation. After subacromial injection, symptomatic subjects demonstrate increased anterior deltoid firing. Previous in vitro and in vivo studies have suggested that pain leads to deltoid inhibition and that subacromial injection leads to improved deltoid firing and, subsequently, improved shoulder function. This study provides direct evidence that subacromial injection improves deltoid firing in symptomatic subjects with rotator cuff tears. These findings reinforce the concept that deltoid inhibition resulting from pain is an important component of the motor disability associated with rotator cuff tears.

Accuracy and reliability of three different techniques for manual goniometry for wrist motion: a cadaveric study.

PURPOSE: Despite the ubiquitous use of manual goniometry in measuring objective outcomes of hand surgery and therapy, there are limited data concerning its accuracy or repeatability for wrist motion. The purpose of this study was to evaluate the accuracy and reliability (both inter- and intra-rater) in measuring wrist flexion and extension using 3 manual goniometric alignment techniques (ulnar, radial, and dorsal-volar) in cadaveric upper extremities, using fluoroscopic verification of posture as a gold standard. In addition, we sought to assess the accuracy and reliability of the dorsal-volar technique for measurement of radioulnar deviation. METHODS: External fixators were applied to 10 cadaveric wrists with intramedullary cannulated rods in the radius and third metacarpal for gold-standard fluoroscopic verification of posture. Manual goniometric measurements with each technique were captured by 2 raters (a hand surgeon and a hand therapist) for reliability measurements and by a single rater for accuracy. Wrists were positioned at angles of maximum flexion, extension, and radial and ulnar deviation for reliability testing and at preselected angles across the range of motion for accuracy testing. At each position, wrist angle was measured with a 1 degrees increment goniometer, and fluoroscopic angles were measured digitally. Intraclass correlation coefficients and root mean square values were calculated for all combinations, and analysis of variance was used to test differences between techniques. RESULTS: No technique was statistically less accurate than any other (6 degrees to 7 degrees ). Each method was found to have high intra-rater reliability. For measurement of wrist flexion and extension, the dorsal-volar technique demonstrated the greatest inter-rater reliability, as compared to ulnar and radial, respectively. CONCLUSIONS: Although each measurement technique demonstrated a similar degree of accuracy and intra-rater reliability, the dorsal-volar technique demonstrates the greatest level of inter-rater reliability for measurement of wrist flexion and extension. This information is important clinically, as measurements are regularly exchanged between hand surgeons and therapists as a basis for decisions regarding patient care.

Anterior tibial tendon rupture: results of operative treatment.

BACKGROUND: Anterior tibial tendon ruptures are rare, and most studies have reported subjective outcome data, with little or no objective analysis. The purpose of this study was to review the results of the operative treatment of anterior tibial tendon ruptures using the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale and objective isokinetic testing. METHODS: We retrospectively reviewed the results of operatively treated anterior tibial tendon ruptures in 10 patients. The average age at the time of surgery was 57 (18 to 79) years. The etiology of rupture was traumatic in five and spontaneous in five patients. Evaluation consisted of preoperative and postoperative questionnaires, physical examination, and isokinetic strength testing. Average time between surgery and isokinetic testing was 27.9 months. RESULTS: The average AOFAS score was 71.9 preoperatively and 89.8 postoperatively. Eight of 10 patients reported improvement in pain, and nine of 10 patients reported increased activity level postoperatively. All patients were satisfied with the overall function of their foot and would undergo the procedure again. The peak torque generated in the operative extremity during ankle dorsiflexion and hindfoot inversion was less than that of the uninvolved extremity. No statistically significant difference was noted between peak torque generation in ankles treated with direct anterior tibial tendon repair and ankles treated with anterior tibial tendon repair with augmentation. CONCLUSIONS: Operative treatment of anterior tibial tendon rupture resulted in a high level of patient satisfaction; however, isokinetic testing demonstrated a decrease in dorsiflexion and inversion strength compared to the uninjured extremity. The clinical significance of this residual weakness was not apparent in most patients. Patients with anterior tibial tendon ruptures should be forewarned that normal strength may not be a realistic expectation after surgery.

Lower extremity muscle activation and alignment during the soccer instep and side-foot kicks.

STUDY DESIGN: Controlled laboratory study. OBJECTIVES: To quantify phase duration and lower extremity muscle activation and alignment during the most common types of soccer kick-the instep kick and side-foot kick. A second purpose was to test the hypotheses that different patterns of lower extremity muscle activation occur between the 2 types of kicks and between the kicking limb compared to the support limb. BACKGROUND: Soccer players are at risk for lower extremity injury, especially at the knee. Kicking the soccer ball is an essential, common, and distinctive part of a soccer player's activity that plays a role in soccer player injury. Regaining the ability to kick is also essential for soccer athletes to return to play after injury. METHODS: Thirteen male soccer players underwent video motion analysis and electromyography (EMG) of 7 muscles in both the kicking and supporting lower extremity (iliacus, gluteus maximus, gluteus medius, vastus lateralis, vastus medialis, hamstrings, gastrocnemius) and 2 additional muscles in the kicking limb only (hip adductors, tibialis anterior). Five instep and 5 side-foot kicks were recorded for each player. Analysis-of-variance models were used to compare EMG activity between type of kicks and between the kicking and nonkicking lower extremity. RESULTS: Five phases of kicking were identified: (1) preparation, (2) backswing, (3) limb cocking, (4) acceleration, and (5) follow-through. Comparing the kicking limb between the 2 types of kick, significant interaction effects were identified for the hamstrings (P = .02) and the tibialis anterior (P<.01). Greater activation of the kicking limb iliacus (P<.01), gastrocnemius (P<.01), vastus medialis (P = .016), and hip adductors (P<.01) occurred during the instep kick. Significant differences were seen between the kicking limb and the support limb for all muscles during both types of kick. CONCLUSIONS: Certain lower extremity muscle groups face different demands during the soccer instep kick compared to the soccer side-foot kick. Similarly, the support limb muscles face different demands than the kicking limb during both kicks. Better definition of lower extremity function during kicking provides a basis for improved insight into soccer player performance, injury prevention, and rehabilitation.