Radiocapitellar Joint Research Articles

Excision of the Radial Head in Patients Younger Than 18 Years

We evaluated the results of an excision of the radial head in 25 patients (27 operated-on elbows) younger than 18 years with stiff painful radiocapitellar joints. The mean age was 14.2 years (range, 4.6-17.8 years) with average follow-up of 7.8 years. Analysis of the results with a postoperative elbow score revealed excellent or good results in 19 of the 27 elbows of patients. Skeletal maturity of the patient did not alter the results based on the rating scale. Revision surgery to remove appositional bone growth was needed in six of the 12 posttraumatic cases and one of 15 developmental elbows. Cubitus valgus, wrist pain, and ulnar neuropathy were not clinical problems at follow-up examination. Excision of the radial head was beneficial for 70% of patients younger than 18 years with stiff, painful radiocapitellar joints. Results were not improved in patients who had reached skeletal maturity.

Osteochondral Lesions in the Radiocapitellar Joint in the Skeletally Immature: Radiographic, MRI, and Arthroscopic Findings in 13 Consecutive Cases

Radiography, magnetic resonance imaging (MRI), and arthroscopy were performed in 13 consecutive cases of osteochondral lesions of the radiocapitellar joint in 12 patients aged 11-16 years. Nine patients had a high activity level, and two patients had a significant trauma before the onset of symptoms. Symptoms were limited range of motion, pain, and catchings or lockings. Clinical findings were decreased range of motion and lateral elbow tenderness. Radiography revealed loose body, flattening of the humeral capitellum, or subchondral cysts (or a combination of these) in all cases but three. There was a good correlation between MRI and arthroscopic examination. Nine lesions were located in the humeral capitellum, one lesion in the radial head, and in three cases, lesions were found in both sites. Loose-body removal, shaving, or subchondral drilling (or a combination of these) was performed in 11 cases. All surgically treated patients improved in the short run. Awareness of the typical clinical and radiologic picture will allow identification of the cases suitable for arthroscopy and surgical treatment. In these cases, MRI can be omitted.

Biomechanical and computer analysis of radial head prostheses

Radial head fractures can lead to significant upper extremity disability. A comminuted radial head fracture with a medial collateral ligament tear presents a clinical conundrum. The radiocapitellar (RC) joint should be maintained, yet the head frequently cannot be reduced and stabilized. The silicone rubber implant currently available is not biomechanically or clinically satisfactory, and thus there is a need for a more suitable prosthetic replacement for the radial head. We have attempted to design such a prosthesis and have examined prosthetic design with various materials that would best transmit force at the RC joint. Design configurations based on our cadaveric and radiographic measurements were tested with structural finite element method computer analyses. Materials examined included titanium alloy, cobalt-chrome alloy, alumina ceramic, and ultrahigh molecular weight polyethylene (UHMWPE). Metals and ceramic transmitted force at the distal bone and implant interface and strain shielded the proximal radial cortex while UHMWPE distributed load uniformly through the cortex and along the entire bone and implant interface. In addition, load transmission comparisons were made with the intact radial head, with a silicone prosthesis, and with 6 and 10 mm thick UHMWPE prostheses in cadaveric specimens. UHMWPE prostheses transmit more force to the RC joint than the silicone prosthesis and with loads closer to physiologic levels at all flexion angles. UHMWPE prostheses not only transmit much more force than silicone, but because of substantially less deformation under load, also provide more stability to the joint.

Acute annular ligament interposition into the radiocapitellar joint in children (nursemaid's elbow).

Acute annular ligament interposition into the radiocapitellar joint ("nursemaid's elbow") is a common injury in children younger than 5 years. The injury occurs when axial traction is applied to an extended, pronated arm. There are no abnormal radiographic findings associated with this condition. We recommend that children with a classic history and clinical presentation of an acute annular ligament interposition into the radiocapitellar joint be treated without obtaining radiographs.

Biomechanical Aspects of the Elbow in Sports

In many sports, large forces and torques are produced at the elbow that lead to fast movements and a full range of motion. In baseball pitching. varus torque is produced when the arm is in external rotation. This torque includes compression at the radiocapitellar joint and tension in the ulnar collateral ligament (UCL). After ball release, compressive force approaching 100% of bodyweight is produced to prevent elbow dislocation. Compared to baseball pitching, football passing produces greater elbow flexion and medial force, and less varus torque: Furthermore, elbow extension is not as rapid and arm deceleration compressive force is not as great. During the tennis serve, elbow extension is largely due to triceps contraction. During javelin throwing. the elbow extends fairly quickly, terminating well short of full extension. During underhand Softball pitching, the elbow produces compressive force and fairly rapid flexion. Elbow compressive force during pushups is equal to 45% of bodyweight. Compressive force during two-arm pushups (which are similar to falling on an arm) is 31% greater.

Pulled elbow in childhood

In this injury, a sudden pull on the pronated, extended arm of a child up to 5 years of age is followed by refusal to use the arm. After a simple flexion, supination and extension manoeuvre the child starts using the arm in minutes. Radiographs are said to be normal. At least 13 theories of the mechanism have been advanced. Anterior subluxation of the radial head has never been proved radiographically or experimentally. Available evidence favours momentary distraction of the radiocapitellar joint in pronation which allows upward slip of the annular ligament upon the radial head at its shortest diameter and interposition of part of the anterior capsule between the two bones. Radiography is difficult, usually producing oblique views in pronation which are not easy to interpret. The main differential diagnosis is from epiphyseal rotation. In any doubtful case early repeat radiography is essential taking matched views of both elbows, even if non-standard. A collection of 28 radiographs has been analysed, two recent typical contrasting cases are presented, two signs to identify an oblique view of a normal elbow are described and the literature is reviewed. If the best radiograph available in an injured elbow in a child is a normal oblique view in pronation, pulled elbow is a likely diagnosis.

A syndrome of dislocated hips and radial heads, carpal coalition, and short stature in Puerto Rican children.

An orthopaedic syndrome that apparently had not been reported previously was identified in twenty-three children. Characteristics shared by all twenty-three children included Hispanic descent, residence in Puerto Rico, bilateral dislocation of the hip, dislocated radial heads, short stature, and other osseous anomalies. Twelve dislocated hips in six patients were not treated. All of these hips were functioning satisfactorily at the time of the review, but only four of the children had reached skeletal maturity. Sixteen hips in eight patients remained reduced after closed reduction. Of these eight patients, the four who were skeletally immature at the time of the review had a satisfactory result, and the four who were skeletally mature had an unsatisfactory result because of discomfort or fibrous ankylosis. Eighteen hips in nine patients were treated with a reduction augmented by some form of operation. All of these hips redislocated. Of the forty-six elbows in the twenty-three children, thirty-three were dislocated, as seen clinically and radiographically; eight were normal, both clinically and radiographically; and there was dysplasia at the radiocapitellar articulation of the remaining five. Twenty of the twenty-three children were found to have carpal coalitions. Fourteen children had scoliosis, and five of them were managed with spinal arthrodesis and correction. Three patients had an anomaly of the cervical spine, with one deformity causing symptoms and signs that were treated with decompression. Eight patients had talipes cavus bilaterally, which was not treated.

Osteochondritis dissecans of the lateral humeral condyle in a table tennis player

The case of a table tennis player suffering from intra-articular loose bodies of the elbow is reported. The patient developed the first signs of osteochondritis dissecans of the right lateral humeral condyle at age 16 but underwent surgery only 6 yr later. He has now resumed training and competition, despite some residual stiffness due to early osteoarthritis. This is the first case of osteochondritis dissecans of the elbow ascribed to this sport. It was probably due to repetitive valgus compressive stresses at the radiocapitellar joint during the forced movements imposed by high-level table tennis in a young athlete.

Radiographic changes with radial head subluxation in children

Radial head subluxation (RHS) produces no radiographic abnormalities according to most experts. However, recent anecdotal case reports have identified displacement of the radiocapitellar line (RCL) in pediatric patients with RHS. To verify this finding, we retrospectively reviewed all patients less than 5 years of age who received elbow and forearm radiographs in our emergency department. From January 1988 through April 1989, we identified 20 cases of RHS. Of the 20 radiographs, 5 (25%) were read by the attending radiologist as abnormal due to RCL displacement indicating subluxation of the radiocapitellar articulation. All 5 of these radiographs had RCL displacement greater than 3 mm. The remaining normal radiographs had RCL displacement less than or equal to 3 mm. The presence of RCL displacement without disruption of the radiocapitellar articulation confirms the diagnosis of RHS, but does not appear to change treatment or outcome in this subset of patients. In addition, radiographs may not be mandatory when the diagnosis of RHS is certain. We suggest obtaining radiographs if the history (i.e., fall) or physical examination is atypical or if reduction is unsuccessful to rule out more serious injuries such as radial head dislocation or fracture.

Bilateral intra-articular loose bodies of the elbow in an adolescent BMX rider

The case of an adolescent BMX rider suffering from bilateral intra-articular loose bodies of the elbow is reported. He underwent surgery to remove these. He is now asymptomatic and has resumed BMX riding. This is the first overuse injury to be ascribed to this sport. It is probably due to repetitive valgus compression stresses at the radiocapitellar joint during the acrobatic manoeuvres of a typical BMX riding session.

Osteochondritis in the female gymnast's elbow

Ten cases of osteochondritis dissecans of the humeral capitellum are reviewed in seven high-performance female gymnasts, ranging in age from 10 to 17 years old. All but one were evaluated and treated with arthroscopy and/or arthrotomy, with curettage of loose articular margins, drilling of the lesion, and removal of loose bodies. The average length of follow-up is 2.9 years, and includes interview, physical examination, and roentgenographic evaluation. This injury has been previously described in relation to compressive forces across the radiocapitellar joint from repetitive valgus loading in a developing epiphysis. Only one of the athletes, at the time of follow-up, was still in competitive gymnastics. Each has a minimal limitation in range of motion, with crepitus and often catching noted by history and on examination. These cases double the limited literature on this injury in young, female gymnasts. They stimulate concern for the proper and early evaluation and treatment of elbow injuries in this at risk group. Once the bony changes in the capitellum are detected, and pain remains despite conservative management, we have found that symptoms can be improved with surgery, but persist in female gymnasts. Our experience in this more-advanced group is that the return to high-level competitive gymnastics is unlikely.

Silicone Rubber Replacement of the Severely Fractured Radial Head

Ten patients, at an average of 3.4 years after Swanson silicone rubber radial head replacement following acute trauma, were evaluated for pain, motion, and grip strength. Three had excellent results, one had a fair result, and two had poor results. Three patients had arthritis at the distal radioulnar joint. The arthritis was correlated with a positive ulnar variance in the uninjured wrist. Degenerative arthritis at the elbow was present in 56% (five out of nine). Ulnar variance was increased significantly in the wrists on the injured side, compared with the opposite wrist and to a control group. A 20-kg grip stress radiograph analysis showed the silicone rubber prostheses to deform and wrist subluxation to occur. A biomechanical study of six human cadaver upper extremities indicated that the flexible implants transferred minimal forces across the radiocapitellar joint. A radial head replacement with a modulus of elasticity similar to bone showed a more physiologic loading at the elbow. Both the clinical and biomechanical studies indicated that the silicone rubber prostheses is unable to transmit physiologic forces from the proximal radius to the capitellum. A less flexible radial head prosthesis should provide more normal physiologic stresses and may lead to improved clinical results.