The distal biceps tendon: footprint and relevant clinical anatomy

PURPOSE: There is little information in the literature describing the anatomy of the biceps tendon insertion. The purpose of this study was to map the footprint of the biceps tendon insertion on the bicipital tuberosity and to report on the relevant anatomy to assist surgeons with correct tendon orientation during surgical repair. METHODS: Fifteen fresh-frozen adult upper extremities were used in this study. The relationships between the long head of the biceps tendon, the short head of the biceps tendon, the muscle bellies, and the distal tendon orientation were examined. The length, width, and area of the biceps tendon insertion were measured. RESULTS: In all specimens examined, the biceps musculotendinous unit rotated 90 degrees externally from origin to insertion. The long head of the distal tendon was inserted onto the proximal aspect of the bicipital tuberosity, while the short head of the distal tendon was inserted onto the distal aspect of the tuberosity. The lacertus fibrosus, in all specimens, originated from the distal short head of the biceps tendon. On average, the biceps tendon insertion started 23 mm distal to the articular margin of the radial head. The average length of the biceps tendon insertion on the tuberosity was 21 mm, and the average width was 7 mm. The average total area of the biceps tendon insertion (footprint) was 108 mm(2). The average area of the long head of the biceps tendon insertion was 48 mm(2), and the average area of the short head of the biceps tendon insertion was 60 mm(2). CONCLUSIONS: Landmarks have been identified that will allow anatomic orientation of the distal biceps tendon during operative repair. The distal short head of the biceps tendon has a consistent relationship with the lacertus fibrosus and a distinct insertion on the bicipital tuberosity. The dimensions of the distal biceps tendon footprint have been determined to assist with bone tunnel or suture anchor placement during surgical repair.     

Distal biceps tendon insertion: an anatomic study

Knowledge of the exact location of the distal biceps brachii insertion is crucial when performing tendon reconstruction or repair. To quantitatively describe the morphology of the distal biceps brachii insertion, 20 cadaveric arms were examined. Linear and angular measurements, including the footprint dimensions and shape, radial tuberosity dimensions and irregularities, and the rotational position of the tuberosity and footprint, were obtained. The axial and transverse dimensions of the radial tuberosity and distal biceps tendon footprint measured 24.2 x 12 mm and 18.7 x 3.7 mm, respectively. The insertion footprint is on the posterior/ulnar aspect of the radial tuberosity centered at approximately 30 degrees anterior to the lateral/coronal plane with the forearm fully supinated. This explains why any preoperative limitation in supination may make an anatomic repair difficult through a single anterior incision. To our knowledge, this is the first study to quantitatively describe the angular location of the radial tuberosity and the relationship of the distal biceps tendon on the tuberosity.     

Partial rupture of the distal biceps tendon

Partial rupture of the distal biceps tendon is a relatively rare event, and various degrees of partial tendon tears have been reported. In the current study four patients with partial atraumatic distal biceps tendon tears (mean age, 59 years; range, 40-82 years) are reported. In all four patients, a common clinical pattern emerged. Pain at the insertion of the distal biceps tendon in the radius unrelated to any traumatic event was the main symptom. In all patients the diagnosis was based on magnetic resonance imaging or computed tomography imaging. In three of four patients the partial rupture of the tendon caused a significant bursalike lesion. The typical appearance was a partially ruptured biceps tendon, with contrast enhancement signaling the degree of degeneration, tenosynovitis, and soft tissue swelling extending along the tendon semicircular to the proximal radius. In three patients, conservative treatment was successful. Only one patient needed surgery, with reinsertion of the tendon resulting in total functional recovery.     

Anatomy of the distal brachioradialis and its potential relationship to distal radius fracture

PURPOSE: To describe the anatomy of the brachioradialis (BR), paying special attention to its insertion in relation to the surrounding structures in cadavers and evaluating and correlating this information with a distal radius fracture pattern in a clinical population. METHODS: Eighteen fresh-frozen cadaver arms were dissected to observe the gross anatomy of the BR. The dimensions of the insertion were measured using a caliper and a 3-dimensional digitizer. The radiographs of 34 patients with 35 distal radius fractures were reviewed and the fracture pattern was compared with the normalized location of the BR insertion based on the cadaver measurements. RESULTS: On average the BR tendon inserted onto the proximal base of the first dorsal compartment 17 mm from the radial styloid tip and extended 15 mm proximally; the insertion was 11 mm wide. The BR insertion was bordered consistently by both septa of the first dorsal compartment, forming a tunnel-like structure of thick fibrous tissue on the radial aspect of the distal radius. The whole length of the tendon attached firmly to the underlying antebrachial fascia, which limited excursion. In 18 of the fractures the fracture line deviated from transverse to proximal at the radial side, forming a radial beak. The proximal tip of the beak correlated with the expected location of the proximal end of the BR tendon insertion. CONCLUSIONS: The BR distal tendon insertion is a consistent, distinct insertion at the base of the first dorsal compartment, which correlates with the radial-beak fracture pattern in approximately 50% of distal radius fractures. Cutting the BR tendon disconnects the distal fragment from the BR muscle and the forearm fascia, which may facilitate reduction of the distal radial fragments during open reduction of the distal radius fracture.     

The 70° Supinated Oblique View: A Cadaveric Analysis to Determine Ideal Radial Styloid Screw Position in Locked Volar Plating of Distal Radius Fractures

Background: Defining an intraoperative radiographic view to best determine the radial styloid screw position in locked volar plating of distal radius fractures may improve fixation and aid in decreasing cortical penetration and implant complication. We used a cadaveric model to demonstrate a reproducible, oblique radiographic view to identify the radial styloid screw position. Methods: Nine fresh-frozen elbow-to-fingertip cadavers were used for this study. A 2.4-mm variable angle volar distal radius locking plate was applied to the distal radius. A Kirschner wire (K-wire) was inserted into the radial styloid through the plate. Placement of the K-wire through the tip of the styloid at the cortical edge was confirmed through a separate radial incision. A second K-wire was placed through the radius shaft into the ulna to aid in angular measurements. Live fluoroscopic imaging was used as the forearm was brought from full 90° of supination toward neutral. Once the K-wire was abutting the cortical edge, rotation ceased, and a goniometer was used to measure the angle of forearm rotation. This was repeated for a total of 3 repetitions on each specimen. Results: The average angle of supination best depicting the position of the radial styloid screw was 68.5° (range = 64.3°-70.5°). Conclusions: Radial styloid screw fixation in locked volar plating of distal radius fractures increases the ultimate strength to failure, but screw penetration and tendon irritation can occur. The 70° supinated oblique intraoperative view provides the most accurate evaluation of the position of the radial styloid screw.     

Load-sharing at the wrist following radial head replacement with a metal implant. A cadaveric study

BACKGROUND: Surgical excision of the radial head is frequently required after a comminuted fracture of the radial head. The outcome of this procedure is often unpredictable, with some patients experiencing ulna-sided pain in the wrist secondary to proximal migration of the radius. Insertion of a radial head prosthesis could prevent proximal radial migration and restore normal load-sharing at the wrist. The thickness of the radial head implant is an important variable in restoring anatomical radial length; however, the effects of varying the length of implants that were used to reconstruct the radius on load-sharing at the wrist have not been studied biomechanically, to our knowledge. METHODS: A miniature load cell was attached to fifteen fresh-frozen cadaveric forearms to record force in the distal part of the ulna as the wrist was axially loaded to 134 N of compression force. Proximal displacement of the radius relative to the capitellum was also recorded. Loading tests on intact forearms were performed with the elbow in valgus and varus alignment and with three positions of wrist rotation (neutral, 45 degrees of pronation, and 45 degrees of supination). Loading tests were then repeated, with the same positions of varus and valgus elbow alignment and wrist rotation as had been used in the tests of the intact forearm, after radial head excision and subsequent insertion of metal radial head implants that restored anatomical length, implants that produced a radial length that was longer than the anatomical length, and implants that produced a radial length that was shorter than the anatomical length. Testing of these different implant thicknesses was repeated after sectioning of the interosseous membrane. RESULTS: The mean distal ulnar forces and mean proximal radial displacements following insertion of an implant that restored anatomical length were not significantly different from the corresponding values for the intact forearm. At neutral wrist rotation, replacing that implant with an implant that increased the radial length by 4 mm (after sectioning of the interosseous membrane) decreased the mean distal ulnar force from 13.4% to 3.3% of the applied wrist force with the elbow in valgus alignment and from 29.1% to 8.6% with the elbow in varus alignment. Replacing the implant that restored anatomical length with one that decreased the length by 4 mm (after sectioning of the interosseous membrane) significantly increased the mean distal ulnar force from 13.4% of the applied wrist load to 33.3% with the elbow in valgus alignment and from 29.1% to 51.6% with it in varus alignment. The mean distal ulnar forces were not significantly affected by the position of wrist rotation when the elbow was in valgus alignment. However, when the elbow was in varus alignment, the mean distal ulnar forces associated with all reconstructed radial lengths were significantly higher when the wrist was placed in 45 degrees of supination. CONCLUSIONS: In this cadaveric model, insertion of a metal implant maintained distal ulnar forces at normal levels, at all three positions of wrist rotation, when the radius had been restored to its original anatomical length. Distal ulnar forces and proximal radial displacements were significantly affected by the reconstructed length of the radius. CLINICAL RELEVANCE: Radial head implants are utilized to prevent proximal migration of the radius as the wrist is loaded; this is especially important when the interosseous membrane has been ruptured and thus cannot help to limit radial displacement. At the time of surgery, comminution and displacement of a radial head fracture may make estimation of the original radial length difficult. Our results demonstrate that, in terms of distal ulnar loading, it is preferable to insert an implant that is too thick rather than too thin.     

Cross-sectional anatomy of the bicipital tuberosity and biceps brachii tendon insertion: relevance to anatomic tendon repair

This study evaluated the insertional anatomy and orientation of the biceps tuberosity and tendon to assess the anatomic validity of repairs made with 1 incision vs 2 incisions. Computed axial tomography was used to image 30 cadaver radii, and each tendon insertion was measured with a digital micrometer. Specimens were sectioned and imaged with Faxitron radiography (Faxitron X-Ray Corp, Wheeling, IL) to determine the angular orientation of the biceps tendon insertion relative to the tuberosity apex. The tuberosity axis of orientation averaged 65 degrees (range, 15 degrees -120 degrees ) of pronation from anterior, with angular orientation encompassing a mean 59 degrees (range, 15 degrees -100 degrees ) arc with the midpoint of the insertion averaging 50 degrees (range, -5 degrees to 105 degrees ). Most biceps tendons inserted on the anterior aspect of the apex of the tuberosity, with an average width of 7 mm and length of 22 mm. The biceps tuberosity is oriented in more pronation than is typically described, prohibiting anatomic reinsertion of the tendon in 35% of specimens with current single-incision techniques.     

Radiological findings in distal radius fractures

X-ray examination in distal radius fractures is very important for the management and prognostic of these fractures. Anterior and lateral radiographs must be taken in standardised position to avoid errors in measurements. On antero-posterior x-ray of the distal radius the important parameters are: radial length (N = 11-12 mm), radial angle (N = 22 degrees-25 degrees) and radial width. For the radial length three methods of measurements (Gartland, Gelberman and Palmer) are presented. On the lateral x-ray the palmar inclination of the distal radius may be measured (N = 10 degrees-12 degrees). Modifications of these parameters associated with distal radius fractures are presented.     

Graft reconstruction of the interosseous membrane in conjunction with metallic radial head replacement: a cadaveric study

PURPOSE: Longitudinal radioulnar dissociation (Essex-Lopresti injury) occurs when traumatic axial loading through the wrist disrupts the interosseous membrane (IOM) of the forearm and fractures the radial head. Proximal migration of the radius results in an ulnar-positive wrist, which can lead to painful ulnar-sided wrist degeneration and distal radioulnar joint instability. The purpose of this study was to measure the ability of an IOM reconstruction used in combination with a metal prosthetic radial head implant to reduce distal ulnar forces in a cadaveric model. The effects of varying the initial graft pretension on distal ulnar force were also studied. METHODS: Twelve fresh frozen and thawed cadaveric forearms had a miniature load cell installed to record force in the distal ulna as the wrist was loaded axially to 134 N of compression force in neutral rotation. Intact forearms were tested first with the elbow in valgus and varus alignments. Loading tests were repeated after (1) insertion of a metal radial head implant that restored radius anatomic length, (2) excision of the IOM (with a radial head implant), and (3) reconstruction of the IOM using a palmaris longus tendon autograft (with a radial head implant). The implant then was removed and loading tests were repeated using 3 levels of initial graft pretension. RESULTS: Mean distal ulnar forces with an intact forearm were 23% of applied wrist force in the varus alignment and 12% in the valgus alignment. Mean force levels after insertion of the implant were 18% (varus) and 13% (valgus); these were not significantly different from corresponding values for the intact forearm. Mean force levels after section of the IOM were 30% (varus) and 14% (valgus); these were not significantly different from corresponding values for the intact forearm (varus and valgus) but the mean for varus was significantly greater than the corresponding value with an implant. After IOM reconstruction with a palmaris longus tendon tensioned to 22 N mean distal ulnar forces were 8% (varus) and 7% (valgus); these means were significantly less than the corresponding values for all prior test conditions. With the radial head removed increasing the level of graft pretension reduced significantly mean distal ulnar force. CONCLUSIONS: With the IOM resected insertion of a metal radial head implant alone did not reduce distal ulnar forces to intact forearm levels. When an IOM reconstruction was performed in combination with the implant mean distal ulnar force was reduced significantly to a level below that for the intact forearm. Applying pretension to the graft displaced the radius distally thereby making the wrist more ulnar negative and reducing distal ulnar force. Our results suggest that an IOM reconstruction used in combination with a metal radial head implant theoretically could help reduce distal ulnar impaction in an Essex-Lopresti injury.     

Anatomic parameters for planning of interosseous ligament reconstruction using computer-assisted techniques

PURPOSE: Longitudinal radioulnar dissociation may result when both interosseous ligament (IOL) disruption and radial head fracture occur. Although radial head salvage or arthroplasty and temporary distal radioulnar joint pinning constitute the standard treatment for this injury, IOL reconstruction has been proposed to restore more normal forearm axis mechanics. To help provide an anatomic basis for IOL reconstruction, the purpose of this study was to characterize the geometry of the central band of the IOL and simulated IOL reconstructions. METHODS: Twenty forearms free of pathology were dissected to bone-IOL-bone and computed tomography scans were taken. Computer models of radius-IOL-ulna were created from the computed tomography CT images, and computer-aided design software was used to measure key parameters for IOL reconstruction and simulate anatomic IOL reconstructions. RESULTS: The insertion site locations of the IOL central band along the radius and ulna from the wrist were 57 +/- 3% and 34 +/- 4% of bone length, respectively. The angle at which the IOL central band inserts with the ulna was 24 +/- 4 degrees, which agrees with previously reported values. We found that the minimum graft length needed to anatomically span both cortices through tunnels was 112 +/- 14 mm. CONCLUSIONS: These data will help to provide a basis for planning and performing IOL reconstruction in cases of longitudinal radioulnar dissociation.     

Bicortical K-wires for distal radius fracture fixation: how many?

The aim of this study was to find out whether number and position of K-wires influence the stability of distal radius fractures treated by percutaneous wire fixation. Patients who underwent K-wire fixation for unstable fractures of the distal radius over a period of three years were included in this retrospective study. Radiographs taken immediately after the procedure and radiographs taken after removal of K-wires were analysed to study three radiological parameters: palmar or dorsal tilt, radial inclination and ulnar variance. Loss of these angles was analysed statistically against the number of wires (2 or 3) and position of wires (from radial styloid or a combination of styloid and dorsal wires). Ninety-five fractures were analysed with a mean age of 52.8 years and male to female ratio of 1:2. Average loss of radial inclination was 5.2 degrees, loss of palmar tilt was 8.3 degrees and loss of ulnar variance was 3.4 mm. Using 3 wires or using a dorsal wire in addition to the styloid wires both improved the final radial length by 1.2 mm and 2 mm respectively, but the effects were statistically not significant. We found that the number or position of wires did not influence radiological outcome. Based on our findings we recommend the use of two K-wires: one from the radial styloid and one from the dorsal side for these fractures.     

Distal biceps tendon injuries: diagnosis and management.

Rupture of the distal biceps tendon occurs most commonly in the dominant extremity of men between 40 and 60 years of age when an unexpected extension force is applied to the flexed arm. Although previously thought to be an uncommon injury, distal biceps tendon ruptures are being reported with increasing frequency. The rupture typically occurs at the tendon insertion into the radial tuberosity in an area of preexisting tendon degeneration. The diagnosis is made on the basis of a history of a painful, tearing sensation in the antecubital region. Physical examination demonstrates a palpable and visible deformity of the distal biceps muscle belly with weakness in flexion and supination. The ability to palpate the tendon in the antecubital fossa may indicate partial tearing of the biceps tendon. Plain radiographs may show hypertrophic bone formation at the radial tuberosity. Magnetic resonance imaging is generally not required to diagnose a complete rupture but may be useful in the case of a partial rupture. Early surgical reattachment to the radial tuberosity is recommended for optimal results. A modified two-incision technique is the most widely used method of repair, but anterior single-incision techniques may be equally effective provided the radial nerve is protected. The patient with a chronic rupture may benefit from surgical reattachment, but proximal retraction and scarring of the muscle belly can make tendon mobilization difficult, and inadequate length of the distal biceps tendon may necessitate tendon augmentation. Postoperative rehabilitation must emphasize protected return of motion for the first 8 weeks after repair. Formal strengthening may begin as early as 8 weeks, with a return to unrestricted activities, including lifting, by 5 months.     

Volar fixation of dorsally displaced distal radius fractures using the 2.4-mm locking compression plates

PURPOSE: To determine whether volar fixed-angle plate fixation with a new plate system could be used to treat dorsally unstable distal radius fractures. We hypothesized that volar fixed-angle plate fixation with or without radial styloid fixed-angle plate fixation would provide sufficient rigidity to allow early active range of motion without compromising fracture reduction. The initiation of early active motion may improve functional outcomes. METHODS: A retrospective review was conducted of one institution's initial experience using a new volar fixed-angle plate system to treat dorsally displaced intra-articular and extra-articular distal radius fractures. Thirty-two fractures in 32 patients with dorsally displaced distal radius fractures were treated with a volar fixed-angle plate with or without a radial styloid fixed-angle plate. Fractures were classified using the AO classification. Radiographic parameters on preoperative, postoperative, and final follow-up radiographs were compared. The time to initiation of active range of motion was determined. Final follow-up ranges of motion and complications were reported. Finally, comparisons were made between the 23 fractures treated with a volar plate alone and the 9 fractures treated with a volar plate and a radial styloid plate. RESULTS: The average follow-up period was 13 months. Two thirds of the fractures were intra-articular. Average loss of reduction from initial postoperative to final follow-up radiographs was 0 degrees of volar tilt, 1 degrees of radial inclination, and 0 mm of radial length. Active wrist and forearm ranges of motion were initiated at an average of 11 days after surgery. The final follow-up flexion-extension and pronation-supination arcs averaged 112 degrees and 151 degrees , respectively. The 9 fractures treated with the combination of a fixed-angle volar plate with a fixed-angle radial styloid plate had greater initial displacement than did the 23 fractures treated with a volar plate alone. Otherwise, differences between the 2 groups were not significant. Only 1 radial styloid plate became symptomatic. CONCLUSIONS: Volar plate fixation using a new fixed-angle plate system successfully can stabilize dorsally unstable distal radius fractures. Early active range of motion was facilitated without compromising fracture reduction.     

Three-dimensional in vivo kinematics of the distal radioulnar joint in malunited distal radius fractures

How malunion of the distal radius affects the kinematics of the distal radioulnar joint in vivo was evaluated. A novel computed tomography image-based technique was used to quantify radioulnar motion in both wrists of 9 patients who had unilateral malunited distal radius fractures. In the injured wrists dorsal angulation averaged 21 degrees +/- 6 degrees, radial inclination averaged 18 degrees +/- 5 degrees, and radial shortening averaged 21 +/- 3 mm. Clinically, the average range of motion of the injured wrists was 75 degrees +/- 25 degrees pronation and 73 degrees +/- 23 degrees supination. Kinematics of the radius during pronation and supination in the malunited forearms was indistinguishable from that in the uninjured forearms. In both the axis of rotation of the radius passed through the center of the ulnar head, although it shifted slightly ulnar and volar in supination and radial and dorsal during pronation. In contrast to previous in vitro biomechanical findings, there was no dorsovolar radial translation at the extremes of pronation or supination and no translation of the radius along the rotation axis. Soft tissues may play a larger role in limiting function than previously appreciated, and treatment may require correction of altered soft tissue structures as well as any abnormal bone anatomy.     

Reconstruction of elbow flexion by transposition of pedicled long head of triceps brachii muscle

A new technique of restored flexion in the elbow joint in an inveterate injury of the brachial plexus is described. The insertion of the long head of the triceps brachii muscle was transferred with an intact nervous and vascular supply to the anterior brachial region and sutured above the radial tuberosity with the insertion tendon of the biceps brachii muscle. The muscle strength three months after surgery according to the muscle test was 4-. Flexion in the elbow joint was possible up to 85 degrees. Extension in the elbow joint was preserved, the muscle strength was 3. Anatomical investigation revealed that the mean length of the nerve of the long head of the triceps was 5.5 cm, the number of terminal branches was 3-4, 70% of the vascular supply was from the brachial artery, the length of the vascular bundle was 3.6 cm. In 33% there was an additional neurovascular hilus which was 2-3 cm distally from the main hilus. The investigation confirms that the neurovascular pedicle of the long head of the triceps brachii muscle is sufficiently mobile and damage by traction during transposition of the insertion tendon is therefore not likely. Transfer of the long head of the triceps brachii muscle in inveterate injuries of the brachial plexus is a suitable alternative for reconstruction of nerves or transfer of other muscles to restore flexion in the elbow joint.     

Clinical presentation and radiographic findings of distal biceps tendon degeneration: a potentially forgotten cause of proximal radial forearm pain

For patients who present insidiously with proximal-radial forearm pain, the differential diagnosis should include distal biceps tendon degeneration. If radial tunnel and pronator syndromes, lateral epicondylitis, and radiocapitellar arthritis are eliminated as potential causes, tenderness over the proximal radius, supination weakness, and characteristic radiographic or magnetic resonance imaging findings may facilitate correct diagnosis of distal biceps tendon degeneration. In this article, we describe the clinical presentation and radiographic findings for 5 patients who presented with distal biceps degeneration.     

Computerized analysis of radiographs in Colles' fractures

Several radiographic parameters correlate with clinical outcome in distal radius fractures. This study describes a new, computerized routine that automatically defines the longitudinal axis of the radius, deriving the radial tilt, radial width, and radial height on anteroposterior radiographs of the wrist. The intraobserver and interobserver variability is reported in a series of 33 anteroposterior radiographs of the wrist. An edge-finding filter is used to determine accurately the cortices in several lines of each image. The midpoints between these two edges are used to determine the best-fit line, thereby defining the longitudinal axis of the bone. The operator marks the tip of the radial styloid and the lunate angle of the radius at the distal radioulnar joint. Radial shortening, widening, and loss of angle are calculated. The 33 radiographs were measured twice by two independent observers, and 12 sets of paired readings were analyzed using the two-tailed paired t test. The mean difference between readings was reduced to a fraction of degree or millimeter, virtually eliminating the intraobserver and interobserver errors. Thus, the current study shows the computer is a reliable and effective instrument for measuring radiographs. The computer-aided system of measurements can be extended to prostheses, fractures, and to other orthopaedic measurements.     

Repositioning and stabilization of the radial styloid process in comminuted fractures of the distal radius using a single approach: the radio-volar double plating technique

Background  

A possible difficulty in intra-articular fracture of the distal radius is the displacement tendency of the radial styloid process due to the tension of the brachioradialis tendon.     

Mechanisms of load transfer in the cadaver forearm: role of the interosseous membrane

Forces transmitted through the distal ulna and proximal radius, relative motion between the radial head and capitellum, and measurements of tissue strain and local fiber tension within the central band of the interosseous membrane were recorded as cadaveric forearms were loaded axially through the wrist. With the elbow in valgus alignment (the radial head in direct contact with the capitellum), an average of 93% of force applied to the wrist was transferred directly through the radius to the elbow with no appreciable load transfer through the interosseous membrane. With varus alignment (initial gap between the radial head and capitellum) load applied to the wrist displaced the radius proximally an average of 1.1 mm until radial head contact occurred at a mean applied wrist force of 89.0 N. Proximal displacement of the radius generated strain in the central band of the interosseous membrane and created a more ulnar positive wrist, which in turn increased distal ulnar loading; distal ulnar force averaged 19% and interosseous membrane averaged 54% of applied wrist force. Distal ulnar loading was unaffected by 25 degrees wrist flexion-extension or by 20 degrees of radioulnar deviation. With 40 degrees ulnar deviation, mean distal ulnar forces were 18% and 48% of applied wrist force for valgus and varus elbow alignments, respectively. Mean load-sharing percentages at the wrist and elbow were not significantly different between 222. 5 N and 133.5 N of applied force for any wrist position and were unaffected by the angle of elbow flexion.     

Injuries of the biceps brachii muscle with special reference to surgical therapy

Injuries of M. biceps brachii are rare, in most cases (greater than 90%) the long tendon is involved, seldom the distal tendon. The long tendon usually ruptures in the sulcus intertubercularis, preexisting degenerative changes play an important role. The distal tendon most often ruptures traumatically at its radial insertion. Injuries of the short tendon do not require operative treatment, whereas complete ruptures of the venter of the muscle and of the distal tendon have to be operated on, in doing so the distal tendon should be reinserted at the radius. Ruptures of the long tendon may be treated conservatively, operation is indicated in young and active patients with painful functional lesion. In these cases proximal refixation under good tension should be realized. In accordance with bibliographical data our case material (11 operations) shows satisfying results in about 75%, though persistent pain or some functional lesion following operative treatment of ruptures of the long tendon has been observed in half of the patients. Finally general conclusions concerning indication and methods of operative treatment are made.