Radial head fractures.

The shape and size of the radial head is highly variable but correlates to the contralateral side. The radial head is a secondary stabilizer to valgus stress and provides lateral stability. The modified Mason-Hotchkiss classification is the most commonly used and describes three types, depending on the number of fragments and their displacement. Type 1 fractures are typically treated conservatively. Surgical reduction and fixation are recommended for type 2 fractures, if there is a mechanical block to motion. This can be done arthroscopically or open. Controversy exists for two-part fractures with >2 mm and <5 mm displacement, without a mechanical bloc as good results have been published with conservative treatment. Type 3 fractures are often treated with radial head replacement. Although radial head resection is also an option as long-term results have been shown to be favourable. Radial head arthroplasty is recommended in type 3 fractures with ligamentous injury or proximal ulna fractures. Failure of primary radial head replacement may be due to several factors. Identification of the cause of failure is essential. Failed radial head arthroplasty can be treated by implant removal alone, interposition arthroplasty, revision radial head replacement either as a single stage or two-stage procedure.

Failure of metal radial head replacement.

There is little information available at present regarding the mechanisms of failure of modern metallic radial head implants. Between 1998 and 2008, 44 consecutive patients (47 elbows) underwent removal of a failed metallic radial head replacement. In 13 patients (13 elbows) the initial operation had been undertaken within one week of a fracture of the radial head, at one to six weeks in seven patients (seven elbows) and more than six weeks (mean of 2.5 years (2 to 65 months)) in 22 patients (25 elbows). In the remaining two elbows the replacement was inserted for non-traumatic reasons. The most common indication for further surgery was painful loosening (31 elbows). Revision was undertaken for stiffness in 18 elbows, instability in nine, and deep infection in two. There were signs of over-lengthening of the radius in 11 elbows. Degenerative changes were found in all but one. Only three loose implants had been fixed with cement. Instability was not identified in any of the bipolar implants.

Atypical acute rejection after hand transplantation.

Skin rejection after hand transplantation is characterized by a maculopapular erythematous rash that may be diffuse, patchy or focal, and distributed over forearms and dorsum of the hands. This 'classical' pattern of rejection usually spares the skin of the palm and does not affect the nails. Herein, we report the experience on four cases presenting with an 'atypical' pattern of rejection that is novel in involving the palmar skin and the nails. All patients were young and exposed to repetitive and persistent mechanical stress of the palm. Characteristic features of rejection included a desquamative rash associated with dry skin, red papules, scaling and lichenification localized to the palm. Skin lesions were associated with nail dystrophy, degeneration, deformation or loss. Histology of the skin and nail bed revealed a lymphocytic infiltrate with predominance of T cells (CD3+, CD4+ and CD8+), with small numbers of B cells (CD20+ and CD79a+) and a low number of Forkhead transcription factor 3 (FOXP3)-positive cells in one patient. The lesions persisted over weeks to months, responded poorly to steroid treatment and were managed with antithymocyte globulin (ATG; Thymoglobulin, Genzyme, Cambridge, MA), alemtuzumab and/or intensified maintenance immunosuppression.

Distal biceps tendon anatomy: a cadaveric study.

BACKGROUND: The anatomy of the distal biceps tendon and aponeurosis has not been studied in detail. METHODS: Seventeen cadaver elbows were dissected with loupe magnification to identify the details of the distal biceps tendon and the lacertus fibrosus. RESULTS: In ten of the seventeen specimens, the distal biceps tendon was in two distinct parts, each a continuation of the long and short heads of the muscle. The remaining seven specimens showed interdigitation of the muscle distally. The tendon continued from each muscle belly. The short head inserted distal to the radial tuberosity and was positioned to be a more powerful flexor of the elbow, while the tendon of the long head inserted on the tuberosity further from the axis of rotation of the forearm and was positioned to be a stronger supinator. The bicipital aponeurosis consisted of three layers and completely encircled the ulnar forearm flexor muscles. The aponeurosis may be important in stabilizing the tendons distally. CONCLUSIONS: The double tendon insertion may allow an element of independent function of each portion of the biceps, and, during repair of an avulsion, the surgeon should ensure correct orientation of both tendon components.

Validation of the lesser sigmoid notch of the ulna as a reference point for accurate placement of a prosthesis for the head of the radius: a cadaver study.

We undertook a study on eight arms from fresh cadavers to define the clinical usefulness of the lesser sigmoid notch as a landmark when reconstructing the length of the neck of the radius in replacement of the head with a prosthesis. The head was resected and its height measured, along with several control measurements. This was compared with in situ measurements from the stump of the neck to the proximal edge of the lesser sigmoid notch of the ulna. All the measurements were performed three times by three observers acting independently. The results were highly reproducible with intra- and interclass correlations of > 0.99. The mean difference between the measurement on the excised head and the distance from the stump of the neck and the lesser sigmoid notch was -0.02 mm (-1.24 to +0.97). This difference was not statistically significant (p = 0.78). The proximal edge of the lesser sigmoid notch provides a reliable landmark for positioning a replacement of the radial head and may have clinical application.

Heterotopic ossification causing proximal radioulnar synostosis after insertion of a radial head prosthesis.

A rare case of radioulnar synostosis following placement of a metal radial head replacement is described and a review of treatment options for heterotopic ossification in the vicinity of the elbow is presented.

The effect of the orientation of the radial head on the kinematics of the ulnohumeral joint and force transmission through the radiocapitellar joint.

Background. The treatment of radial head fractures that are not amenable to an open reduction and internal fixation, remains to be a difficult issue. A potential problem with prosthetic replacement of the radial head is the shape of current radial head prostheses. The purpose of this study was to determine the effect of the shape of the radial head on kinematics and load transfer of the elbow. Methods. Kinematics of the elbow and radiocapitellar force transmission were measured in 6 fresh frozen upper extremities. The effect of radial head shape was tested by rotating the head 90 degrees , with a custom-made 'native' radial head prosthesis. 3-D spatial orientation of the ulna showed an average difference in ulnohumeral laxity, between the nominal and 90 degrees conditions, of 0.1 degrees throughout the arc of motion with neutral forearm rotation (maximum: 2 degrees ). Findings. We found an average difference in ulnar axial rotation, of 0.1 degrees (maximum: 1.9 degrees ). No differences showed statistical significance. Radiohumeral joint force was measured and maximally showed a 32 times increase of force in the altered shape conditions. Interpretation. Our results show that the kinematics of the elbow was not affected by altering the shape of the radial head, but it did adversely affect the forces in the radiohumeral joint. This could possibly generate degenerative changes in the elbow.

The kinematic importance of radial neck length in radial head replacement.

Comminuted radial head fractures can be treated with a radial head implant. The effects of lengthening (2.5 mm, 5 mm) and shortening (2.5 mm, 5 mm) of the radial neck, were compared to the nominal length in six human upper extremity cadavers. Total varus-valgus laxity and ulnar rotation were recorded. We hypothesized that restoring the exact length of the radius is important to maintain normal kinematics in the elbow joint. Lengthening or shortening of more than 2.5 mm significantly changed elbow kinematics. Lengthening caused a significant decrease (p < 0.001) in varus-valgus laxity, with the ulna tracking in varus and external rotation. Shortening caused a significant increase in varus-valgus laxity (p < 0.001) and ulnar rotation (p < 0.001), with the ulna tracking in valgus and internal rotation. Our study suggests that a restoration of radial length is important and that axial understuffing or overstuffing the radiohumeral joint by 2.5 mm or more, will alter elbow kinematics.

Detrimental effects of overstuffing or understuffing with a radial head replacement in the medial collateral-ligament deficient elbow.

BACKGROUND: Comminuted radial head fractures associated with an injury of the medial collateral ligament can be treated with a radial head implant. We hypothesized that lengthening and shortening of the radial neck would alter the kinematics and the pressure through the radiocapitellar joint in the medial collateral ligament-deficient elbow. METHODS: The effects of lengthening (2.5 and 5 mm) and shortening (2.5 and 5 mm) of the radial neck were assessed in six human cadaveric upper extremities in which the medial collateral ligament had been surgically released. The three-dimensional spatial orientation of the ulna was recorded during simulated active motion from extension to flexion. Total varus-valgus laxity and ulnar rotation were measured. Radiocapitellar joint pressure was assessed with use of pressure-sensitive film. RESULTS: Radial neck lengthening or shortening of >/=2.5 mm significantly changed the kinematics in the medial collateral ligament-deficient elbow. Lengthening caused a significant decrease (p < 0.05) in varus-valgus laxity and ulnar rotation (p < 0.05), with the ulna tracking in varus and external rotation. Shortening caused a significant increase in varus-valgus laxity (p < 0.05) and ulnar rotation (p < 0.05), with the ulna tracking in valgus and internal rotation. The pressure on the radiocapitellar joint was significantly increased after 2.5 mm of lengthening. CONCLUSIONS: This study suggests that accurate restoration of radial length is important and that axial understuffing or overstuffing of the radiohumeral joint by >/=2.5 mm alters both elbow kinematics and radiocapitellar pressure. CLINICAL RELEVANCE: This in vitro cadaver study indicates that a radial head replacement should be performed with the same level of concern for accuracy and reproducibility of component position and orientation as is appropriate with any other prosthesis.

Anatomical considerations of the radius.

Most radial head prostheses do not seem to be based on anatomic data. This may be due partly to the great variation of radial morphology. More importantly, few articles report on the dimensions of the radius. Authors have mainly studied dimensions of the radial head, with less emphasis to the relationship with the rest of the radius. Dimensions of, and relationship between, the proximal and the rest of the radius were measured on 27 fresh-frozen cadaveric upper extremities. Radial head, articulating surface, diaphysis, and distal radius were measured. Angles between the radial neck and diaphysis were defined and calculated. Axes of the distal and proximal radius were defined and radial torsion was calculated. Repeated measures were done by two observers in ten specimens. Inter- and intra-class correlation coefficients were very acceptable. Radial dimensions were found to be highly variable. Calculation of radial torsion showed the largest range. The average torsion was 54 degrees (range = 23-78 degrees). Radial length was 235 mm (range = 207-269 mm). Radial neck length was 13 mm (range = 9-19 mm). We found an average proximal diaphysis-neck angle of 17 degrees (range = 6-28 degrees). End to end-neck angle was 13 degrees (range = 4-22 degrees). Our findings indicate that even with a perfectly anatomical prosthesis, restoration of the anatomical situation can only be achieved when the implant is placed in the correct position. Instrumentation should be developed to allow accurate and reproducible implantation. The measurements we provide may aid this development.

The effect of the orientation of the noncircular radial head on elbow kinematics.

OBJECTIVE: The objective of this study was to identify the effect of radial head shape and orientation on elbow kinematics in the otherwise intact elbow. DESIGN: Biomechanical study, analyzing simulated active motion of cadaveric arms. BACKGROUND: A discrepancy exists between the noncircular anatomy of the radial head and radial head prostheses. The effect of radial head shape is unknown. METHODS: Kinematic effects of radial head shape were tested in six fresh-frozen upper extremities. A custom-made native radial head prosthesis was used to simulate altered shape conditions, by rotating the radial head 90 degrees. Three-dimensional spatial orientation of the ulna was recorded, during simulated active motion. A three factor ANOVA was used to compare (a) nominal and 90 degrees oriented conditions, (b) throughout the flexion arc (c) in three forearm positions (P < 0.05). Post-hoc Tukey tests were done to assess significance. RESULTS: No significant effect of altering radial head shape was found on total ulnohumeral laxity and angulation during gravity valgus stress. We did find a significant effect on total ulnar axial rotation and rotation during gravity valgus stress. CONCLUSION: The outer shape of the radial head seems to change rotation of the ulna during flexion-extension in an otherwise intact elbow. RELEVANCE: The shape of the radial head effects intact elbow kinematics. Clinical importance of this finding is clear. If a sub-optimally placed radial head prosthesis were to be used in an otherwise intact elbow, the elbow could be at risk for early ulnohumeral arthritis.

Arthroscopic subacromial decompression for advanced (stage II) impingement syndrome: a study of 52 patients with five years follow-up.

The authors report a prospective five-year follow-up study of 52 patients who had arthroscopic subacromial decompression for advanced (stage II: type 1 and 2) rotator cuff disease. All patients were assessed preoperatively, at six months and at five years postoperatively using the Constant-Murley score and the revised American Shoulder and Elbow Surgeons (ASES) score. From six months until five years postoperatively, 45 (out of 52) patients showed a further progressing improvement and relief of symptoms. This is established by a significant (p < 0.001) increase of the mean Constant-Murley score from 76.4 at six months postoperatively to 84.9 at five years postoperatively.