Elbow Joint

Purpose Displaced olecranon fractures are often amenable to treatment with open reduction and tension-band wiring. The purpose of this study is to examine the relationships of the tips of K-wires used in a tension-band construct to volar neurovascular structures in the proximal forearm and the proximal radioulnar joint.

The aim of this study was to apply models derived from the robotics field to evaluate the human upper-limb force generation capacity. Four models were compared: the force ellipsoid (FE) and force polytope (FP) based on unit joint torques and the scaled FE (SFE) and scaled FP (SFP) based on maximum isometric joint torques. The four models were assessed from four upper-limb postures with varying elbow flexion (40°, 60°, 80° and 100°) measured by an optoelectronic system and their corresponding isometric joint torques. Ten subjects were recruited. Three specific ellipsoids and polytopes parameters were compared: isotropy, principal force orientation and volume. Isotropy showed that the ellipsoids and polytopes were elongated. The angle between the two ellipsoids main axis and the two polytopes remained low but increased with the elbow flexion. The FE and FP volumes increased and those of SFE and SFP decreased with the elbow flexion. The interest and limits of such models are discussed ...

The purpose of the study was to find whether the early and late phases of relaxation from maximal voluntary contraction depend on the elbow joint angle and whether the influence of joint angle on relaxation depends on which optimal angle (Ao or Ao (MVC) ) was considered as a reference value. Ao (MVC) was the optimal elbow joint angle at which elbow flexor muscles can produce maximum voluntary force and Ao was the optimal angle at which the fastest rates and shortest time of relaxation occur. Twenty-two young, physical education male students were tested four times. The first and second sessions were done to establish optimal angles (Ao, Ao (MVC) ). The third and fourth sessions were done to measure the relaxation indices at an optimal angle, as well as at the angles that were smaller (As=optimal-30º) and larger (Al=optimal+50º). All testing sessions consisted of four trials of 2 or 3-s MVC at each angle. To assess the speed of relaxation, the following relaxation indices were measured: early, late and latest relaxation rate (ERR, LRR, and LstRR, respectively; %F/5ms), maximal rate of relaxation (MRR; %F/5ms), and half relaxation time (1/2Rt; ms). The BIODYNA dynamometer was used to measure torque versus time curve for right elbow flexor muscles. The maximum voluntary force was produced at the angle Ao (MVC) =89.4±8.0°. The end force (EF) had the best score at 89.2°±8.4°. The optimal angles (Ao) for relaxation indices were ERR=90.9°±8.2°; LRR=88.3°±8.8°; LstRR=89.5°±9.8°; MRR=90.3°±7.5°; and 1/2Rt=87.9°±8.5°. The differences were not statistically significant. Although the Ao and Ao (MVC) were similar, most subjects had values for Ao that were 5°-10° smaller or larger than Ao (MVC) . Moreover, a small difference between MVC at Ao and Ao (MVC) (1.1%) was accompanied by much bigger differences for relaxation indices. At Ao: ERR, LRR, and MRR were 10% to 12% higher, LstRR-25% higher and 1/2Rt 10% shorter compared to the values at Ao (MVC) . The optimal elbow joint angle at which elbow flexor muscles produced maximum voluntary force (Ao (MVC) ) did not always coincide with the angle at which relaxation indices had the best results (Ao). Nevertheless, unlike the relaxation of single muscle following electrostimulation, the indices of early and late relaxation of elbow flexor muscles Reprint request to: Prof. Anna Jaskólska, Academy of Physical Education,

We investigated the feasibility of arthroscopically assisted reduction and fixation of small coronoid fractures and the anterior capsule for treatment of patients with Regan and Morrey Types I and II (O'Driscoll Types I and II) coronoid fractures with instability of the ulnohumeral joint. Four consecutive patients with this fracture type underwent arthroscopically assisted treatment and were evaluated at a minimum of 1 year (mean, 76 weeks; range, 58-92 weeks). All patients achieved a functional range of motion with an average flexion/extension arc of 2.5°to 140°a nd full pronation and supination. No patient had recurrent elbow instability. One patient had removal of a prominent suture over the subcutaneous border of the ulna. Arthroscopically assisted management of coronoid fractures can provide excellent observation, enabling anatomic repair without extensive soft tissue dissection. Preservation of the soft tissue attachments of small coronoid fragments and repair of the capsule are possible with this technique. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Transfers are one of the most physically demanding wheelchair activities. The purpose of this study was to determine if using proper transfer skills as measured by the Transfer Assessment Instrument (TAI) is associated with reduced loading on the upper extremities. Twenty-three wheelchair users performed transfers to a level-height bench while a series of forces plates, load cells, and a motion capture system recorded the biomechanics of their natural transferring techniques. Their transfer skills were simultaneously evaluated by two study clinicians using the TAI. Logistic regression and multiple linear regression models were used to determine the relationships between TAI scores and the kinetic variables on both arms across all joints. The results showed that the TAI measured transfer skills were closely associated with the magnitude and timing of joint moments (P < .02, model R(2) values ranged from 0.27 to 0.79). Proper completion of the skills which targeted the trailing arm...

In 1954, Norell described the 'fat pad sign' for the first time. This refers to the radiological visualization of the elbow fatty tissue. This is a prospective study with the aim of clarifying the relation between the presence of a positive fat pad sign on the lateral radiograph and the type of injury verified on MRI. From January to December 2010, 31 children were diagnosed primarily with a positive fat pad sign. An above-the-elbow cast was applied and all patients were referred for an MRI within a few days. All patients were recommended a clinical follow-up and informed about the MRI results. After revision, five patients were found to have a negative fat pad sign and were excluded. This resulted in a total of 26 patients, 10 men and 16 women, mean age 10±2.62 years. The time between the injury and the initial radiological examination was 0.8±0.27 days and the MRI was obtained on an average of 6.6±3.84 days. A total of 12 patients had an injury of the left side and 14 of the right side. The MRI showed a posterior positive sign in all except five cases and six occult fractures, which accounts for 23%. Nineteen patients (73%) had a bone bruise. All patients except one had a normal range of movement with no pain on the last clinical examination after 2-3 weeks. The presence of a positive fad pad sign is not synonymous with occult fractures. Finding occult fractures on MRI does not alter the final treatment of these patients. On the basis of this study and review of other similar studies, pediatric patients who presented with elbow effusion verified on conventional radiographs could be treated with a cast for 2-3 weeks and extra clinical or radiological controls did not seem to be indicated. Level of evidence: Level III, development of diagnostic criteria on the basis of consecutive patients.

The aim of the present study was to evaluate and compare both clinically and roentgenographically 62 extension-type supracondylar fractures on the basis of the synthesis method and the severity of the fracture, with a mean follow up of 4 years and 3 months. Range of motion, elbow's axial alignment, muscle strength and joint stability were estimated and the MAYO Elbow Performance Index (MEPI) and the POSNA-PODCI questionnaire were used. Furthermore we performed radiographic measurements (Baumann's angle, Humero-capitellar angle and Lateral Rotational Percentage). According to Flynn criteria, the clinical outcome of all our patients was satisfactory. From the results of the questionnaires, no patients has reported any disabling limitation of the elbow function. Radiographic study proved a greater capacity of remodelling in the sagittal plane compared to the frontal one, irrespective of severity of fracture assessed by the Gartland classification. Statistical analysis stressed the validity of postoperative Baumann's angle as predictor of final carrying angle. Regarding the synthesis method the best way to approach Gartland II fractures proved to be by closed reduction and percutaneous pinning; the use of a third Kirschner wire in the treatment of Gartland III fractures did not lead to a better result. To conclude, remodelling positively influenced the clinical outcome, however, irrespective of synthesis method and severity of the fracture, we should pay more attention to the adequacy of reduction in frontal plane than in the sagittal one, for which a greater capacity of remodelling was proved.

Proper biomechanics help baseball pitchers minimize their risk of injury and maximize performance. However previous studies involved adult pitchers only. In this study, 23 youth, 33 high school, 115 college, and 60 professional baseball pitchers were analyzed. Sixteen kinematic (11 position and "ve velocity), eight kinetic, and six temporal parameters were calculated and compared among the four levels of competition. Only one of the 11 kinematic position parameters showed signi"cant di!erences among the four levels, while all "ve velocity parameters showed signi"cant di!erences. All eight kinetic parameters increased signi"cantly with competition level. None of the six temporal parameters showed signi"cant di!erences. Since 16 of the 17 position and temporal parameters showed no signi"cant di!erences, this study supports the philosophy that a child should be taught &proper' pitching mechanics for use throughout a career. Kinetic di!erences observed suggest greater injury risk at higher competition levels. Since adult pitchers did not demonstrate di!erent position or temporal patterns than younger pitchers, increases in joint forces and torques were most likely due to increased strength and muscle mass in the higher level athlete. The greater shoulder and elbow angular velocities produced by high-level pitchers were most likely due to the greater torques they generated during the arm cocking and acceleration phases. The combination of more arm angular velocity and a longer arm resulted in greater linear ball velocity for the higher level pitcher. Thus, it appears that the natural progression for successful pitching is to learn proper mechanics as early as possible, and build strength as the body matures.

Objective: The major contributors to physical disability after stroke are considered to be the negative impairments of loss of dexterity (defined here as loss of the ability to co-ordinate muscle activity in the performance of any motor task) and loss of strength. The aims of this study were: (1) to determine the relative contributions of strength and dexterity to function