Is Immobilization Necessary for Early Return to Work Following Distal Biceps Repair Using a Cortical Button Technique?: A Randomized Controlled Trial.

BACKGROUND: Improvements in surgical fixation to repair distal biceps tendon ruptures have not fully translated to earlier postoperative mobilization; it is unknown whether earlier mobilization affords earlier functional return to work. This parallel-arm randomized controlled trial compared the impact of early mobilization versus 6 weeks of postoperative immobilization following distal biceps tendon repair. METHODS: One hundred and one male participants with a distal biceps tendon rupture that was amenable to a primary repair with use of a cortical button were randomized to early mobilization (self-weaning from sling and performance of active range of motion as tolerated during first 6 weeks) (n = 49) or 6 weeks of immobilization (splinting for 6 weeks with no active range of motion) (n = 52). Follow-up assessments were performed by a blinded assessor at 2 and 6 weeks and at 3, 6, and 12 months. At 12 months, distal biceps tendon integrity was verified with ultrasound. The primary outcome was return to work. Secondary outcomes were pain, range of motion, strength, shortened Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH) score, and tendon integrity. Intention-to-treat analysis was performed. A linear mixed model for repeated measures was used to compare pain, range of motion, strength, and QuickDASH between the groups over time; return to work was assessed with use of independent t tests. RESULTS: The groups were similar preoperatively (p ≥ 0.16). The average age (and standard deviation) was 44.7 ± 8.6 years. Eighty-three participants (82%) were followed to 12 months. There were no differences between the groups in terms of return to work (p ≥ 0.83). Participants in the early mobilization group had significantly more passive forearm supination (p = 0.04), with passive forearm pronation (p = 0.06) and active extension and supination (p = 0.09) trending toward significantly greater range of motion in the early mobilization group relative to the immobilization group. Participants in the early mobilization group had significantly better QuickDASH scores over time than those in the immobilization group (p = 0.02). There were no differences between the groups in terms of pain (p ≥ 0.45), active range of motion (p ≥ 0.09), or strength (p ≥ 0.70). Two participants (2.0%, 1 in each group) had full-thickness tears on ultrasound at 12 months (p = 0.61). Compliance was not significantly different between the groups (p = 0.16). CONCLUSIONS: Early motion after distal biceps tendon repair with cortical button fixation is well tolerated and does not appear to be associated with adverse outcomes. No clinically important group differences were seen. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Rotational Anatomy of the Radius and Ulna: Surgical Implications.

PURPOSE: The rotational anatomy of the forearm bones is not well defined. This study aims to further the understanding of the torsion of the radius and ulna to better guide treatment. METHODS: Computed tomography images of 98 cadaveric forearms were obtained and 3-dimensional models of the radius and ulna were generated and analyzed. The rotation of the radius was evaluated by comparing the orientation of the distal radius central axis (DRCA) with the volar cortex of the distal radius (DR) and biceps tuberosity (BT). The rotation of the ulna was evaluated by assessing the orientation of the ulnar head with respect to the proximal ulna. RESULTS: The DR volar cortex pronates from distal to proximal. The BT was 43.8° ± 16.9° supinated from the DRCA (range, 2.7°-86.5°). The mean difference in rotation between contralateral biceps tuberosities was 7.0° ± 7.1°. The volar cortex of the DR was 12.6° ± 5.4° supinated compared with the DRCA. The ulnar head was pronated 8.4° ± 14.9° with respect to the greater sigmoid notch (range, 50.3° pronation-22.0° supination). CONCLUSIONS: The BT has a variable orientation relative to the DR, but it is generally located anteromedially in a supinated arm or 136° opposite the radial styloid. Understanding the rotational anatomy of the radius and ulna can play an important role in surgical planning and implant design. The rotational anatomy of the radius and ulna varies significantly between individuals, but is similar in contralateral limbs. CLINICAL RELEVANCE: Distal radius volar cortex rotational anatomy can help guide treatment of DR fractures and malunions as well as assist in positioning of wrist arthroplasty implants, particularly in the presence of bone loss. The side-to-side similarities demonstrated in this study should be helpful in managing patients with segmental bone loss or fracture malunion and those requiring joint reconstruction.

In vitro assessment of the contact mechanics of reverse-engineered distal humeral hemiarthroplasty prostheses.

BACKGROUND: Distal humeral hemiarthroplasty alters cartilage contact mechanics, which may predispose to osteoarthritis. Current prostheses do not replicate the native anatomy, and therefore contribute to these changes. We hypothesized that prostheses reverse-engineered from the native bone shape would provide similar contact patterns as the native articulation. METHODS: Reverse-engineered hemiarthroplasty prostheses were manufactured for five cadaveric elbows based on CT images of the distal humerus. Passive flexion trials with constant muscle forces were performed with the native articulation intact while bone motions were recorded using a motion tracking system. Motion trials were then repeated after the distal humerus was replaced with a corresponding reverse-engineered prosthesis. Contact areas and patterns were reconstructed using computer models created from CT scan images combined with the motion tracker data. The total contact areas, as well as the contact area within smaller sub-regions of the ulna and radius, were analyzed for changes resulting from hemiarthroplasty using repeated-measures ANOVAs. FINDINGS: Contact area at the ulna and radius decreased on average 42% (SD 19%, P=.008) and 41% (SD 42%, P=.096), respectively. Contact area decreases were not uniform throughout the different sub-regions, suggesting that contact patterns were also altered. INTERPRETATION: Reverse-engineered prostheses did not reproduce the same contact pattern as the native joints, possibly because the thickness of the distal humerus cartilage layer was neglected when generating the prosthesis shapes or as a consequence of the increased stiffness of the metallic implants. Alternative design strategies and materials for hemiarthroplasty should be considered in future work.

The effect of distal humeral hemiarthroplasty on articular contact of the elbow.

BACKGROUND: Hemiarthroplasty is a treatment option for selected distal humerus fractures. The purpose of this study was to determine the effect of distal humeral hemiarthroplasty and implant size on elbow articular contact. We hypothesized that implants of varying sizes produce different contact patterns compared with the native elbow. METHODS: Eight cadaveric arms were tested in an elbow simulator and the kinematics recorded. Three-dimensional reconstructions of bones and cartilage were generated from computed-tomography images to determine contact patterns. The native articulation was compared to optimal, oversized, and undersized implants (Latitude Anatomic Hemiarthroplasty). Changes in contact patterns relative to the native articulation were measured using total contact area and contact patch agreement scores, defined as the sum of distance between contact patches×area, indicating how well contact patches agree with the native contact pattern. FINDINGS: The native articulation had significantly lower ulnohumeral contact patch agreement scores compared to all tested implants (P<0.05). Mean ulnohumeral and radiocapitellar contact area decreased an average 44% (P=0.03) and 4% (P=0.07) following placement of an optimally sized implant. There was no effect of implant size on contact area or contact patch agreement score (P>0.05). INTERPRETATION: Shape differences of elbow implants relative to the native joint may be responsible for altered contact patterns and could be improved with design modifications. These changes may predispose the elbow to arthritis. The lack of influence of implant size suggests that implant shape and materials may be more important than implant sizing during surgery.

Radial head fractures.

The radial head is the most commonly fractured bone of the elbow, with most fractures occurring in women older than 50 years. The radial head is an important stabilizer for valgus, axial, and posterolateral rotational forces. Loss of articular segments of the radial head negatively affects elbow kinematics and stability. Most fractures are treated nonsurgically. Indications for nonsurgical treatment include nondisplaced and isolated displaced fractures without a block to motion. Fragment excision is indicated when a mechanical block from a small, displaced fragment impedes elbow motion. If technically possible, open reduction and internal fixation is preferred for larger fragments, whereas radial head arthroplasty is reserved for comminuted fractures if reconstruction of the fragments is not possible. Radial head excision can be considered for isolated, displaced, and comminuted fractures in patients with low functional demands; in the presence of infection; or after other treatment modalities have failed. Complications include stiffness, heterotopic ossification, infection, and instability. The indications for surgical versus nonsurgical management of radial head fractures remain controversial.

Elbow arthroplasty for distal humeral fractures.

The treatment of comminuted, distal humeral fractures in elderly patients with osteoporotic bone is challenging. Total elbow arthroplasty or hemiarthroplasty are reliable treatment options with favorable outcomes for fractures that are not amenable to open reduction and internal fixation. Total elbow arthroplasty is a reliable option for a comminuted distal humeral fracture in an elderly patient with osteoporosis and low functional demands. Longer-term studies have shown good to excellent results and a low risk of complications. Specific indications for hemiarthroplasty are evolving, but include comminuted coronal shear or low transverse fractures in patients who have higher functional demands than those that can be met by total elbow arthroplasty. Further studies with longer-term follow-ups are needed to compare the benefits of hemiarthroplasty with total elbow arthroplasty.

High-speed burr debulking of digital calcinosis cutis in scleroderma patients.

PURPOSE: To evaluate the functional outcome after removal of digital calcinosis cutis in patients with scleroderma using a high-speed burr. METHODS: A retrospective analysis was performed of 9 consecutively enrolled scleroderma patients who underwent surgery by the senior author. A debulking procedure using a high-speed micro-burr to soften and express calcific material in digits was performed. Demographics, complications, recurrence, and postoperative functional outcome measurements including the Disabilities of the Arm, Shoulder, and Hand questionnaire, the Michigan Hand Questionnaire, a study-specific questionnaire, a visual analog scale, and the Short Form-12 were collected. RESULTS: Mean follow-up time was 2 years. Four of 9 patients were very or somewhat satisfied with the procedure. Eight complications were recorded in 6 patients, including weakness, decreased motion, numbness, and superficial wound infection. The mean Disabilities of the Arm, Shoulder, and Hand score in patients who would have surgery again was 27 (4 of 9), versus 54 (5 of 9) for those who would not. Two patients had no recurrence. There were 7 cases of recurrence; 3 patients had late recurrence to a small degree, 3 had early complete recurrence, and 1 had recurrence at an unknown onset. No patient reported complete resolution of calcinosis. Patient satisfaction appeared inversely correlated to the number of digits involved. CONCLUSIONS: Patients with discrete areas of calcinosis cutis, including those with 1 or 2 digits affected, did much better than patients with diffuse disease and multiple affected digits. Patients should be counseled that the benefit might be more limited than previously reported, and recurrence is likely. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Development of a computational technique to measure cartilage contact area.

Computational measurement of joint contact distributions offers the benefit of non-invasive measurements of joint contact without the use of interpositional sensors or casting materials. This paper describes a technique for indirectly measuring joint contact based on overlapping of articular cartilage computer models derived from CT images and positioned using in vitro motion capture data. The accuracy of this technique when using the physiological nonuniform cartilage thickness distribution, or simplified uniform cartilage thickness distributions, is quantified through comparison with direct measurements of contact area made using a casting technique. The efficacy of using indirect contact measurement techniques for measuring the changes in contact area resulting from hemiarthroplasty at the elbow is also quantified. Using the physiological nonuniform cartilage thickness distribution reliably measured contact area (ICC=0.727), but not better than the assumed bone specific uniform cartilage thicknesses (ICC=0.673). When a contact pattern agreement score (s(agree)) was used to assess the accuracy of cartilage contact measurements made using physiological nonuniform or simplified uniform cartilage thickness distributions in terms of size, shape and location, their accuracies were not significantly different (p>0.05). The results of this study demonstrate that cartilage contact can be measured indirectly based on the overlapping of cartilage contact models. However, the results also suggest that in some situations, inter-bone distance measurement and an assumed cartilage thickness may suffice for predicting joint contact patterns.

The anatomy of the superior labrum and biceps origin in the fetal shoulder.

The presence of a sublabral recess has been observed in adult shoulders. It is unclear whether this occurrence is a developmental variation or is acquired. The primary objective of the study was to determine if a cleft exists between the superior labrum and the superior cartilaginous glenoid anlage during the second trimester. The secondary objective was to define the origin of the long head of the biceps in the human fetus in the second trimester. Shoulders of 11 fetuses, 11-20 weeks old, were sectioned in the coronal plane. The superior labrum was observed to be continuous with the superior glenoid anlage, and a cleft was not observed at any stage of development. The biceps tendon originated from the superior labrum and the superior glenoid tubercle anlage in all specimens. Fibers extending in the direction of superior glenoid tubercle anlage were always very prominent.

Characterization of liver histopathology in a transgenic mouse model expressing genotype 1a hepatitis C virus core and envelope proteins 1 and 2.

Hepatitis C virus (HCV) is a major cause of chronic hepatitis and hepatocellular carcinoma worldwide. The purpose of this study was to determine how the HCV structural proteins affect the dynamic structural and functional properties of hepatocytes and measure the extra-hepatic manifestations induced by these viral proteins. A transgenic mouse model was established by expressing core, E1 and E2 proteins downstream of a CMV promoter. HCV RNA was detected using RT-PCR in transgenic mouse model tissues, such as liver, kidney, spleen and heart. Expression of the transgene was analysed by real-time PCR to quantify viral RNA in different tissues at different ages. Immunofluorescence analysis revealed the expression of core, E1 and E2 proteins predominantly in hepatocytes. Lower levels of protein expression were detected in spleen and kidneys. HCV RNA and viral protein expression increased in the liver with age. Histological analysis of liver cells demonstrated steatosis in transgenic mice older than 3 months, which was more progressed with age. Electron microscopy analysis revealed alterations in nuclei, mitochondria and endoplasmic reticulum. HCV structural proteins induce a severe hepatopathy in the transgenic mouse model. These mice became more prone to liver and lymphoid tumour development and hepatocellular carcinoma. In this model, the extra-hepatic effects of HCV, which included swelling of renal tubular cells, were mild. It is likely that the HCV structural proteins mediate some of the histological alterations in hepatocytes by interfering with lipid transport and liver metabolism.