Dominant Elbow Research Articles

Elbow Hemiarthroplasty for Late Reconstruction of a Traumatic Elbow Bone Defect in a Young Patient: A Case Report.

Hemiarthroplasty of the human elbow was first described in 1947 by Mellen and Phalen1. Encouraging follow-up results with good range of motion and substantial pain relief after elbow hemiarthoplasty were published in 19742. Nevertheless, in cases with severe bone loss and comminution, the semiconstrained total elbow arthroplasty has been a very reliable solution during the last decades3,4, especially in elderly patients. However, in active patients with an injured dominant arm, the major mid and long-term complication of these semi or totally linked polyethylene components is the risk of loosening5. In younger patients, the new anatomic elbow hemiarthroplasty offers the possibility of greater mobility, stability, and promising long-term results6. We present the case of a young patient with a comminuted type-IIIB open fracture of the elbow with bone loss of the humeral condyles. After elbow hemiarthroplasty, the final follow-up (4.5 years postoperatively) showed that the treatment had been successful. The patient was informed that data concerning the case would be submitted for publication, and he provided consent. A thirty-one-year-old obese man (body mass index [BMI] of 35) without any other medical comorbidities presented to the emergency department following a motorcycle accident. Clinical and radiographic evaluation demonstrated an open intercondylar fracture (type IIIB according to the Gustilo-Anderson classification7) of the right dominant elbow, with bone loss of the humeral condyles and fracture of the olecranon tip. Complete radial nerve palsy was also noted. Immediate wound irrigation and surgical debridement were performed in the operating room. During surgical exploration, the radial nerve was found to be intact, and no major vascular injury was apparent. Because of extensive soft-tissue damage, internal fixation was not an option. An elbow-bridging external fixator (Orthofix, Lewisville, Texas) was applied, and a local skin flap was …

Paper 177: Effect of Pitching History and Physical Exam Parameters on the MRI Appearance of the UCL in the Dominant Elbow of the Asymptomatic Collegiate Baseball Pitcher

Paper 177: Effect of Pitching History and Physical Exam Parameters on the MRI Appearance of the UCL in the Dominant Elbow of the Asymptomatic Collegiate Baseball Pitcher

Alterations in stress distribution patterns through the forearm joint surface of the elbow in baseball players assessed using computed tomography osteoabsorptiometry

BackgroundThe distribution of subchondral bone density well reflects long-term resultant stress acting on an articular surface in living joints. Consequently, a measurement of the distribution pattern can determine the stress distribution across the elbow joint surface under long-term loading conditions of baseball pitching. Our purpose was to elucidate the characteristic alterations in the distribution pattern of subchondral bone density across the forearm bones of the elbow with pitching activities. The hypothesis is that pitching activities would change the stress distribution in living subjects. MethodsThe analysis was performed using computed tomography (CT) images obtained from the dominant elbow of ten nonthrowing athletes (control group), ten college baseball fielders (fielder group), and ten college baseball pitchers (pitcher group). The distribution pattern of subchondral bone density through the articular surface of the proximal radius and ulna bones was assessed using CT osteoabsorptiometry. ResultsThe maximum density area was located in the posterior part of the trochlea notch in all study participants. This maximum density area was significantly increased in the baseball groups compared with that in the control group. The pitcher group also showed a significant distribution of the maximum density area in the anterior part of the radial head. ConclusionOur analysis indicates that pitching activities increase actual stress on the articular surface not only in the posterior part of the trochlea notch but also in the anterior part of the radial head. The stress across the elbow may be expanded from the ulnohumeral to the radiohumeral joint by repetitive pitching activities in living subjects.

Assessment of eccentric exercise-induced muscle damage of the elbow flexors by tensiomyography

Exercise induced muscle damage (EIMD) impairs maximal torque production which can cause a decline in athletic performance and/or mobility. EIMD is commonly assessed by using maximal voluntary contraction (MVC), creatine kinase (CK) and muscle soreness. We propose as an additional technique, tensiomyography (TMG), recently introduced to measure mechanical and muscle contractile characteristics. The purpose of this study was to determine the validity of TMG in detecting changes in maximal torque following EIMD. Nineteen participants performed eccentric elbow flexions to achieve EIMD on the non- dominant arm and used the dominant elbow flexor as a control. TMG parameters, MVC and rate of torque development (RTD) were measured prior to EIMD and repeated for another six consecutive days. Creatine kinase, muscle soreness and limb girth were also measured during this period. Twenty four hours after inducing EIMD, MVC torque, RTD and TMG maximal displacement had significantly (p<0.01) declined by 37%, 44% and 31%, respectively. By day 6 MVC, RTD and TMG recovered to 12%, 24% and 17% of respective pre-EIMD values. In conclusion, as hypothesised TMG maximal displacement significantly followed other standard EIMD responses. This could therefore be useful in detecting muscle damage from impaired muscle function and its recovery following EIMD.

Common extensor tendon thickness measurements at the radiocapitellar region in diagnosis of lateral elbow tendinopathy

The aim of this study was to determine the value of measuring common extensor tendon (CET) thickness at the radiocapitellar and capitellar regions with qualitative ultrasonographic findings in the diagnosis of lateral elbow tendinopathy. The study included 164 lateral elbow tendinopathy patients (84 bilateral, 80 unilateral) matched by age, gender, and body mass index with 80 normal subjects. CET was examined using gray-scale and Doppler ultrasonography for tendinopathy, and tendon thickness was measured at two landmark locations: capitellar and radiocapitellar. In tendinopathy, tendon thickness including the dominant capitellar region, increased in every measured location. In the capitellar region of the dominant elbow, the cut-off thickness was 5.15 mm, and in the radiocapitellar region, this value was 4.05 mm. For the non-dominant elbow, the cut-off thickness was 4.61 mm, whereas in the radiocapitellar region, this value was 3.51 mm. The greatest risk of tendinopathy was at the radiocapitellar region on the dominant side. The overall sensitivity and specificity of gray-scale findings were 54% and 88%, respectively, and the addition of Doppler readings did not alter these values. When capitellar measurements were added, the values increased to 79% and 80% for sensitivity and specificity, respectively. These values further increased to 93% and 91%, respectively, when radiocapitellar measurements were included. A second tendon thickness measurement at the radiocapitellar region of CET in addition to the capitellar region is recommended on the grounds that combined qualitative and quantitative evaluation of CET increases the diagnostic per- formance of ultrasonography in lateral elbow tendinopathy.

Kinematic Analysis of the Landing Phase onto an Elevated Surface in Box Drop Plyometric Push Ups

Previous research concerning loading and kinematics of box drop plyometric push ups (DPU) has not assessed the vertical ground reaction forces (vGRF) and kinematics of the landing phase onto an elevated surface during DPU. Landing phase is defined as the time from contact with the boxes to propulsion off the boxes. PURPOSE: To compare the flight height, peak vGRF, and elbow flexion during the landing phase of DPU from 3.8cm (1.5 in), 7.6cm (3 in), and 10.2cm (4.5 in) heights. METHODS: Ten active male subjects (86.0±11.6 kg, 1.82±.07 m, 25±3 yrs) performed four repetitions of each DPU variation in a counterbalanced order. DPU were completed with each upper extremity placed over separate force plates. Boxes were placed on the individual force plates just outside of the subjects self-selected hand separation for the push ups. An electromagnetic tracking system (Motion Monitor, IST, Inc) collected kinematics of the trunk and dominant elbow. From the push up position, peak flight (maximal vertical trunk position during flight), peak vGRF, elbow flexion at ground contact (GC), and elbow displacement (difference between elbow position at GC and peak flexion) were calculated. RESULTS: Significant differences in peak flight (P<.001) and elbow flexion at GC (P<.001) were revealed between DPU variations. Post hoc analysis of peak flight demonstrated peak flight during 3.8cm DPU to be significantly less than 7.6cm DPU (P=.002, d=.58) and 10.2 DPU (P<.001, d=1.17), and 7.6 DPU to be significantly less than 10.2 DPU (P<.001, d=.66). Post hoc analysis of elbow flexion at GC revealed subjects had significantly greater elbow extension during the 3.8cm DPU compared to 10.2cm DPU (P<.001, d=.67). No significant differences were revealed for peak vGRF (P=.253) or elbow displacement (P=.074) between the DPU variations. CONCLUSION: Based on peak flight, as box height increases, the higher the subjects must propel their trunk to land on the boxes. In addition, as the box height increased the subjects landed with more elbow flexion. This may indicate that the difficulty of landing on the higher boxes prompted subjects to compensate with more elbow flexion but not enough to affect peak flight. Future research needs to examine DPU from greater heights to determine if kinematics and forces change with an increase in the height of the boxes in DPU.

Kinematic Analysis of Four Plyometric Push Up Variations

Unlike lower extremity plyometrics, data concerning the loads and intensity associated with upper extremity plyometrics are limited. Previous research concerning upper extremity plyometrics only considered vertical ground reaction force (vGRF) characteristics. PURPOSE: To compare flight height, elbow flexion, elbow displacement, hand separation and peak vGRF between the clap push up (CPU) and box drop push ups (DPU) from 3.8cm (1.5 in), 7.6cm (3 in), and 10.2cm (4.5 in) heights. METHODS: Ten active male subjects (86.0±11.6 kg, 1.82±0.7 m, 25±3 yrs) performed four repetitions of each plyometric push up variation in a counterbalanced order. Push ups were completed with each upper extremity positioned over a separate force plate. An electromagnetic tracking system (Motion Monitor, IST, Inc) collected kinematics of the trunk, dominant elbow and both hands. From the push up position, peak flight (maximal vertical trunk position during flight), elbow flexion at ground contact (GC), elbow displacement (difference between elbow position at GC and peak flexion) and hand separation at GC were calculated. Peak vGRF were also computed under the dominant extremity. RESULTS: Significant peak vGRF differences were revealed between variations (P=.002), with post hoc analyses revealing CPU significantly greater than 3.8cm DPU (P=.011, d=.59), 7.6cm DPU (P=.006, d=.44) and 10.2cm DPU (P=.004, d=.45). Peak flight also revealed significant differences between exercises (P<.001) with post hoc analyses revealing 3.8cm DPU less than 7.6cm DPU (P<.001, d=.96), 10.2cm DPU (P<.001, d=1.57) and CPU (P<.001, d=2.9). Additionally the 7.6cm DPU was significantly less than the 10.2cm DPU (P=.004, d=.76) and CPU (P=.005, d=1.9). There were no significant differences for elbow flexion at GC (P=.116), elbow flexion displacement, (P=.277), or hand separation at GC (P=.194). CONCLUSION: Based on the peak vGRF, it appears the CPU has the greatest intensity. Potentially explaining the peak vGRF is the greater peak flight coupled with no significant variation differences in elbow flexion at GC and elbow flexion displacement. Future research needs to consider how the peak vGRF were similar between the three DPU despite significant difference in peak flight and no significant difference in elbow flexion at GC or elbow displacement.

Hemodynamic Changes In Dominant And Non-dominant Arms Of Tennis Players After Performance

PURPOSE: The dominant extremities of tennis players have structural and physiological adaptation. The aim of present study was to investigate the long-term change in muscle blood flow and oxygenation in active and inactive limbs after tennis performance. METHODS: Nine healthy male professional tennis players were performed a bout of forehand tennis training for 10 min. Before, immediately and after the next two days, muscle oxygenation and blood flow were measured by near-infrared spectroscopy (NIRS) for non-dominant and dominant elbow muscles. RESULTS: The result showed that circumference of racket hand is higher than that of opposite hand. Total hemoglobin (TH) concentration of opposite hand was decreased significantly day 1 after tennis performance. Dominant hand has higher TH than non-dominant hand immediately and 1 day after exercise. Oxygen saturation was decreased significantly in both hands immediately after exercise, and oxygen saturation of dominant hand was significantly higher than that of non-dominant hand on day 1 after exercise. Oxygenated hemoglobin for non-dominant hand was significantly decreased immediately and also day 1 after exercise. Comparably, dominant hand have higher oxygenated hemoglobin than opposite hand on day 1. In addition, deoxygenated hemoglobin for dominant hand significantly increased immediately after exercise. CONCLUSIONS: This result suggests that hemodynamic alteration may be responsible for prolonged structural and physiological adaptation to asymmetric exercise.

Lateral and medial epicondylitis: Role of occupational factors

Epicondylitis is a common upper-extremity musculoskeletal disorder. It is most common at the age of 40-60 years. Epicondylitis seems to affect women more frequently than men. Diagnosis of epicondylitis is clinical and based on symptoms and findings of physical examination. The prevalence of lateral epicondylitis in the general populations is approximately 1.0-1.3% in men and 1.1-4.0% in women and that of medial epicondylitis is nearly 0.3-0.6% in men and 0.3-1.1% in women. The incidence rate of medical consultations has been estimated at 0.3-1.1 for lateral and 0.1 for medial epicondylitis per year per 100 subjects of general practice populations. Of occupational risk factors, forceful activities, high force combined with high repetition or awkward posture and awkward postures are associated with epicondylitis. The number of studies is limited to work-related psychosocial factors and the effects are not as consistent as those of physical load factors. Topical non-steroidal anti-inflammatory drugs, corticosteroid injections and acupuncture provide short-term beneficial effects. Workload modification should be considered, especially in manually strenuous jobs. According to clinical case series, surgical treatment has shown fair to good results; however, the efficacy of surgical treatment has not been evaluated in randomised controlled trials. Poorer prognosis of epicondylitis has been reported for individuals with high level of physical strain at work, non-neutral wrist postures during work activity and for those with the condition on the dominant elbow. Modification of physical factors could reduce the risk or improve the prognosis of epicondylitis.

Electromyographic activity during maximal isometric contraction combined with local sinusoidal vibration

Electromyographic activity during maximal isometric contraction combined with local sinusoidal vibration Study aim: To compare the electromyographic activity during maximal isometric contraction alone or combined with local sinusoidal vibration. Material and methods: A group of 6 men aged 23 - 29 years performed 3 maximal voluntary contractions of the dominant elbow flexors lasting 10 s each and separated by 5-min intermissions. One repetition was without vibration, one was associated with 15-Hz and the other one with 20-Hz vibrations of 5-mm amplitude, the sequence of repetitions being random. A new system to generate local vibration was applied, the parameters of the vibratory stimulus being measured using an accelerometer. Force and EMG activity were also measured. The subjects performed the task in sitting position in a Scott Bench-type device. Results: Mean acceleration RMS significantly (p&lt;0.01) differed between vibration frequencies for the X, Y, Z-axes. No significant differences were found, however, for EMG RMS. Vibration frequencies coincided with the machine-predicted ones; acceleration frequencies around 5 Hz were present in all situations, even without vibration, most likely brought about by tremor. Conclusion: The local vibration applied was not enough to generate different responses in EMG activity. The features of vibratory stimulus confirmed the expected frequency range and revealed frequencies around 5 Hz, that could be attributed to muscle tremor.

Long-Term Stress Distribution Patterns Across the Elbow Joint in Baseball Players Assessed by Computed Tomography Osteoabsorptiometry

Background: The distribution pattern of subchondral bone density is considered to highly reflect the stress distribution across a joint under long-term physiologic loading conditions. Therefore, the biomechanical characteristics over the elbow joint surface under long-term loading conditions of baseball pitching can be determined by a measurement of the distribution pattern. Hypothesis: Stress distribution over the elbow joint surface alters with long-term pitching activities. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Computed tomography (CT) imaging data from the dominant elbow of 10 nonthrowing athletes, 10 college baseball fielders, and 10 college baseball pitchers were collected for the current analysis. The distribution of subchondral bone density through the distal articular surface of the humerus was measured using a CT osteoabsorptiometry method. The quantitative analysis of the obtained data focused on location and size of the maximum density area at the articular surface. Results: The maximum density area of subchondral bone across the articular surface of the distal humerus was located in the posterior part of the trochlea in all subjects. This maximum density area was significantly increased in the pitcher group, compared with that in other groups. Additionally, the pitcher group demonstrated a significant distribution of the maximum density area in the anterior part of the capitellum. Conclusion: The results indicate that actual stress across the elbow is concentrated in the posterior part of the trochlea in humans. Baseball pitching may produce excessive or repetitive stress against not only this part, but also the anterior part of the capitellum. The majority of osteochondritis dissecans lesions affecting the elbow are found in the anterior part of the capitellum in throwing athletes. The results may support an important role of mechanical conditions in the cause of elbow osteochondritis dissecans.

Elbow Joint Active Replication in College Pitchers Following Simulated Game Throwing

Background:Elbow injuries are common in college baseball players. Pitching creates stress and fatigue in and around the elbow. Lack of joint proprioception can contribute to nonphysiological joint loading and injury.Hypothesis:There will be no difference in elbow joint active reproduction sense following a simulated 3-inning pitching sequence.Study Design:Cross-sectional study.Methods:Seventeen collegiate pitchers participated. Each pitcher was bilaterally tested for active elbow range of motion using goniometric technique. Percentages of motion determined positions for further study of elbow joint active replication sense (20%, 35%, 50%, 80%). The elbow was passively taken to a position and held for 10 seconds, then returned to full extension. Pitchers were asked to actively reproduce the angle. The opposite elbow was tested in the same manner. One week later, prethrowing joint position reproduction was tested; then a simulated 3-inning game was thrown. Immediately afterward, elbow joint active replication testing was performed. A repeated-measures analysis of variance analyzed differences.Results:No change in active joint reproduction occurred in the nondominant elbow at any angle tested. Dominant elbows demonstrated significant losses of active joint reproduction following throwing. Significant differences occurred at the 35% and 80% angles (P < .05).Conclusion:Active elbow joint replication sense may be compromised following 3 innings of throwing. Because joint proprioception is thought to be an important component of joint stabilization, an alteration in joint position sense may increase the risk of elbow injury during throwing.Clinical Relevance:Pitching may cause a loss of active elbow joint replication.

Pressure Pain Sensitivity Mapping in Experimentally Induced Lateral Epicondylalgia

The aim of this study was to apply topographical techniques to investigate changes in pressure pain sensitivity after induction of delayed onset muscle soreness (DOMS) in the elbow region in healthy subjects. Pressure pain thresholds (PPT) were assessed over 12 points forming a 3 x 4 matrix (4 points in the superior part, 4 points in the middle, and 4 points in the lower part around the lateral epicondyle) over the dominant elbow in 13 healthy men, and pressure sensitivity maps were calculated. DOMS, as a model for lateral epicondylalgia (LE), was induced by repetitive high-level eccentric contractions of the wrist extensor muscles. PPT maps were assessed before, immediately after, and 24 h after eccentric exercise (DOMS). The two-way repeated-measure ANOVA detected significant differences in mean PPT for the measurement points (F = 5.96, P < 0.001), with lower PPT over the points located over the extensor carpi radialis brevis muscle. There was also a significant effect of time (F = 121.3, P < 0.001) but no time x point location interaction (F = 0.7, P = 0.8). PPT were lower 24 h after (P < 0.001) but not immediately after (P > 0.05) eccentric exercise. The study provides new key information regarding mechanical pain hyperalgesia in experimentally induced LE. Topographical pressure pain sensitivity maps from the elbow region revealed heterogeneously distributed mechanical sensitivity before and during DOMS. The most sensitive localizations for PPT assessment correspond to the muscle belly of the extensor carpi radialis brevis. Our results support the implication of the extensor carpi radialis brevis muscle in LE.

Surgical Treatment of Distal Biceps Rupture

Rupture of the distal biceps tendon accounts for 10% of all biceps brachii ruptures. Injuries typically occur in the dominant elbow of men aged 40 to 49 years during eccentric contraction of the biceps. Degenerative changes, decreased vascularity, and tendon impingement may precede rupture. Although nonsurgical management is an option, healthy, active persons with distal biceps tendon ruptures benefit from early surgical repair, gaining improved strength in forearm supination and, to a lesser degree, elbow flexion. Biomechanical studies have tested the strength and displacement of various repairs; the suspensory cortical button technique exhibits maximum peak load to failure in vitro, and suture anchor and interosseous screw techniques yield the least displacement. Surgical complications include sensory and motor neurapraxia, infection, and heterotopic ossification. Current trends in postoperative rehabilitation include an early return to motion and to activities of daily living.

Anterior Shoulder Laxity Is Not Correlated with Medial Elbow Laxity in High School Baseball Players

Uninjured baseball players have been shown to have increased anterior glenohumeral joint laxity, which may result in adaptive changes at the medial elbow. To determine the relationship between anterior shoulder laxity and medial elbow laxity in both arms of baseball and nonbaseball high school athletes and compare the laxity of dominant and nondominant shoulders and elbows of high school baseball and nonbaseball players. Cohort design. Local high schools. Thirty healthy high school male athletes. Anterior shoulder and medial elbow laxity measurements were taken bilaterally with the Ligmaster. Dominant and nondominant shoulder laxity was significantly greater in the nonbaseball players than the baseball players. No other significant relationships existed. High school baseball players exhibit less anterior shoulder laxity than do nonbaseball players. No relationship exists between anterior shoulder and medial elbow laxity in high school baseball players.

PR_118: Comparisons of Findings of Physical Examination and Ultrasonography Between Both Upper Extremities of University Golfers

Objective: To compare the findings of physical examination and ultrasonography among shoulder, elbow, and wrist joints of university golfers. Design: Cross-sectional, observational study. Setting: Sports medicine laboratory and musculoskeletal ultrasonography room. Participants: 19 university golfers. Interventions: Not applicable. Main Outcome Measures: Outcome measures of physical examination included range of motion (ROM), shoulder impingement test, tenderness on acromioclavicular joints (ACJs), resisted flexion and extension test in wrists, and tenderness on medial and lateral epicondyles. Ultrasonographic outcome measures included the thickness of both rotator cuff tendon and wrist common extensor and flexor tendons. Results: There were no positive findings in impingement test in shoulders, tenderness in the ACJs, resisted flexion and extension test in wrists, tenderness on medial and lateral epicondyles, or several other pain provocation tests. Dominant upper extremities had larger ROM of extension, abduction in shoulder joints, and extension in wrist joint than the nondominant side (P<.05). In ultrasound findings, there were no significant differences in thickness of rotator cuff muscles or long head of biceps brachi. The common extensor tendon of dominant elbow was thicker than that of the nondominant (P<.05). Conclusions: There were several differences between dominant and nondominant upper extremities in physical and ultrasonographic examinations. This asymmetry is thought to be related to the motions of the golf swing.

Quantitative EMG Changes During 12-Week DeLorme's Axiom Strength Training

Strength training is one of the most common exercises practiced in the field of physical therapy or sports training. However, limited methodology is available to evaluate its effect on the target muscle. This study aimed to test the hypothesis that surface electromyographic (EMG) data from both isometric and isotonic exercise can express changes within the muscle during a 12-week strength training program. Ten healthy male volunteer students (5 for training, 5 for controls) from Yonsei University were recruited for evaluation in this study. DeLorme's axiom was practiced for 12 weeks in the dominant elbow flexors and knee extensors of the training group. Tension for 1 repetition maximum and maximal voluntary isometric contraction, and surface EMG information such as the integrated EMG and three variables from the regression line of median frequency (MDF) data were measured at weeks 0, 3, 6, 9, and 12. The limb circumference was measured at weeks 0 and 12. During the strength training, which was enough for the increment of muscle strength and limb circumference, the rectified-integrated EMG and initial MDF increased with a significant linear pattern in both types of contraction. The two surface EMG variables were able to monitor the physiologic muscle changes during the training. Based on these results, we propose that these two surface EMG variables can be used for monitoring electrophysiological changes in the specific muscle that is undergoing the training program, under conditions where the contraction mode for EMG data collection is either static or dynamic.

Factors Correlated with Volleyball Spike Velocity

Background Spike effectiveness represents a determining element in volleyball. To compete at a high level, the player must, in particular, produce a spike characterized by a high ball velocity. Hypothesis Some muscular and physical features could influence ball velocity during the volleyball spike. Study Design Descriptive laboratory study. Methods A total of 19 male volleyball players from the 2 highest Belgian national divisions underwent an isokinetic assessment of the dominant shoulder and elbow. Ball velocity performance (radar gun) during a spike test, morphological feature, and jump capacity (ergo jump) of the player were measured. We tested the relationship between the isokinetic parameters or physical features and field performances represented by spike velocity. We also compared first-division and second-division player data. Results Spike velocity correlated significantly with strength performance of the dominant shoulder (internal rotators) and of the dominant elbow (flexors and extensors) in the concentric mode. Negative correlations were established with the concentric external rotator on internal rotator ratio at 400 deg/s and with the mixed ratio (external rotator at 60 deg/s in the eccentric mode on internal rotator at 240 deg/s in the concentric mode). Positive correlations appeared with both the volleyball players’ jump capacity and body mass index. First-division players differed from second-division players by higher ball velocity and increased jump capacity. Conclusion Some specific strength and physical characteristics correlated significantly with spike performance in high-level volleyball practice. Clinical Relevance Our results could provide useful information for training management and propose some reflections on injury prevention.

Polyethylene Wear After Total Elbow Arthroplasty

Articular wear is considered to be a possible long-term complication of the use of stemmed, coupled elbow replacements with the capacity to correct deformity and restore function. There have been no reports on this topic, to our knowledge. A review of the results of 919 replacements with the semi-constrained linked Coonrad-Morrey total elbow implant, performed between 1981 and 2000, revealed that twelve patients (1.3%) had undergone an isolated exchange of the articular bushings as a result of polyethylene wear. The status of these patients was assessed clinically and radiographically. The mean age of the twelve patients at the time of the initial total elbow replacement was forty-four years compared with a mean age of sixty-two years in the overall group (p < 0.001). Seven of the twelve patients had posttraumatic arthritis, and five had rheumatoid arthritis. Nine patients had extensive deformity. The group consisted of seven women and five men, and ten patients had involvement of the right dominant elbow. The mean age at the bushing revision was fifty-two years, and the bushings were revised at an average of 7.9 years after implantation. All twelve patients reported pain, and five reported crepitus or a squeaking sound. None had extensive osteolysis. The mean duration of follow-up after the bushing exchange was sixty-five months. The mean arc of motion improved from 89 degrees before the surgery to 109 degrees after it. Three of the twelve patients underwent an additional articular revision at fifty-three, fifty-four, and 136 months after the initial bushing exchange. At the time of final follow-up, all twelve patients had functioning elbows. Isolated bushing exchange can be a successful revision procedure in patients with a semi-constrained linked total elbow prosthesis. Younger patients with a posttraumatic condition and/or severe pre-existing deformity are at greater risk for the development of excessive bushing wear. Patients should be cautioned against exceeding the recommended activity and lifting restrictions.

Differences in the force/endurance relationship between young and older men

The aim of the present study was to ascertain if in six young (23-35 years) and in six older (70-72 years) healthy men matched for comparable absolute and specific maximal force of the dominant elbow flexors, differences in isometric endurance, myoelectrical fatigability, and shortening velocity are still recognizable. To assess the specific force, the muscle cross sectional area (CSA) was determined from magnetic resonance imaging (MRI) scans. The performance of the elbow flexors was studied by assessing the isometric endurance times (ET) at different percentages of maximal isometric contraction (MVC), the average muscle fibre conduction velocity of action potentials (CV), and the median frequency (MDF) of the surface electromyogram (sEMG) of the biceps brachii. Finally, the torque-velocity curve was assessed by means of maximal isokinetic contractions at six fixed angular velocities. All data were expressed as the mean (SD). The results showed that: (1) the ET was longer in the older subjects at the highest levels of isometric contraction, independently from the absolute force; (2) the modifications of muscle fibre CV during isometric effort progressed less rapidly in the older than the younger groups, as did those of MDF; and (3) at the same angular velocity, the older subjects exerted less absolute force than the younger subjects. These results suggest an impairment of the neuromuscular system of older men, which is less powerful and less fatigable than that of young men.