Loss of pronation-supination in patients with heterotopic ossification around the elbow.

BACKGROUND: Heterotopic ossification (HO) is a well-recognized cause of limited flexion-extension, but it can also limit pronation-supination. There is a paucity of literature concerning restriction of pronation-supination due to HO. METHODS: We conducted a retrospective review of patients who had undergone elbow surgery for HO removal between January 1, 2003, and September 27, 2013. Computed tomography scans were reviewed to determine the presence of HO restricting forearm rotation and were rated independently by 4 observers. Each elbow was given 1 of 4 scores according to the likelihood that HO was restricting forearm rotation. Agreement was achieved when 3 or 4 observers thought that HO definitely or probably caused a loss of pronation-supination. RESULTS: Of 132 post-traumatic patients undergoing HO excision for restricted elbow motion, 61 (46%) also lacked a functional arc of pronation and supination (50° and 50°, respectively). Of these 61 patients, 32 (53%) were considered to have lost forearm rotation because of HO. The remaining 29 patients (47%) were thought to have restricted forearm rotation for reasons unrelated to HO. DISCUSSION: In this study, loss of pronation-supination affected almost half of the patients (61 of 132 [46%]) undergoing HO excision around the elbow. Of these 61 patients, 32 (52%) had HO extending into the proximal forearm and affecting rotation. From our data, one can expect that about one-quarter (24% of patients in this study, or 32 of 132) with post-traumatic HO of the elbow will have a significant functional loss of pronation-supination due to HO extending into the forearm.

The effect of prosthetic radial head geometry on the distribution and magnitude of radiocapitellar joint contact pressures.

PURPOSE: To determine if radiocapitellar contact pressures would be elevated with nonanatomical (circular) prostheses over those mimicking native anatomy and if such pressures would be related to the depth and contour of the articular dish and to the pattern of prosthetic articulation against the lateral trochlear ridge. METHODS: Three commercially available circular radial head designs were compared with an anatomical radial head and 2 modified anatomical prototype radial head designs in 10 cadaveric specimens. Each prosthesis and specimen combination was loaded in neutral rotation and maximal extension with a custom testing apparatus while measuring contact areas and pressures using thin-film pressure sensors. RESULTS: Anatomical radial head prototype 2 had similar radiocapitellar contact areas and mean pressures as the native radial head; all other designs showed significant decreases in contact area and increased mean pressures. Peak contact pressures were also measured and were significantly elevated with all prostheses tested. Anatomical designs are statistically more likely to mimic normal contact with the lateral trochlear ridge and its adjacent sulcus than circular prostheses. They are also significantly less likely to have contact pressures above the 5 MPa threshold that is thought to be harmful to cartilage. The depth of the articular dish had a significant effect on contact area and pressure. CONCLUSIONS: Commercially available radial head prostheses demonstrated reduced radiocapitellar contact areas and elevated contact pressures during compressive loading. These were significantly greater with symmetrical circular prostheses than with asymmetrical elliptical designs. The prosthesis that best mimicked native contact behavior was the anatomical radial head prototype 2 owing to its design for articulating with the capitellum, the lateral trochlear ridge, and the sulcus between. CLINICAL RELEVANCE: Because radial head prostheses have the potential to cause capitellar erosion or arthritic change, those with lower contact pressures may lead to fewer such complications.

Preoperative nerve imaging using computed tomography in patients with heterotopic ossification of the elbow.

HYPOTHESIS: This study evaluated the usefulness of computed tomography (CT) imaging for preoperative planning of heterotopic ossification (HO) excision, specifically the spatial relationship between HO and radial and median nerves. Our hypotheses were that CT imaging of the elbow can be used (1) to trace the paths of the radial and median nerves, (2) to distinguish the nerves from the heterotopic bone, and (3) to precisely measure distances from the respective nerve to the most clinically relevant HO. MATERIALS AND METHODS: Patients who had HO removed from the elbow were reviewed retrospectively. On the basis of preoperative CT scans, 22 were identified as likely having HO along the pathway of the radial or median nerve. These cases were independently evaluated by 4 observers, who answered these questions: (1) Can the location of the nerve be adequately seen on sequential images to permit tracing of its path for surgical planning? (2) Can the nerve be distinguished from the HO accurately enough to permit measurement of its distance from the bone? Each observer also measured the shortest distance between nerves and the HO. RESULTS: Overall utility of the CT images for visualizing the nerves was high. The radial nerve was more readily distinguished from the HO (21 of 22 cases) than the median nerve (17 of 22 cases). The distance measured from HO was less for the radial nerve (3 mm) than for the median nerve (9 mm). CONCLUSION: This study demonstrates the usefulness of CT imaging to determine the paths of the radial and median nerves and their spatial relationship to HO at the elbow.

Correlation Between Rotator Cuff Tear in Thai Urban Elderly Population and Vitamin D Deficiency.

Background The benefits of vitamin D encompass the augmentation of rotator cuff healing, the enhancement of bone mineral density (BMD), and the fortification of skeletal muscle strength. The vitamin D deficiency in Asian countries appears to be more severe compared to their Western counterparts. This study aims to ascertain the relationship between rotator cuff tears and vitamin D levels in the urban Thai elderly demographic. Our hypothesis posits that vitamin D deficiency will exhibit an association with the occurrence of rotator cuff tears. Materials and methods A prospective clinical trial conducted at a single tertiary was carried out to assess the patients experiencing shoulder pain who were aged 60 years or older. All participants were tested of blood specimens for calciferol concentration and magnetic resonance imaging (MRI). The duration between blood sample collection and magnetic resonance imaging (MRI) did not exceed a two-week window. The assessment of fatty degeneration in the supraspinatus, infraspinatus, and subscapularis muscles, as well as tear dimensions and cartilage thickness, was conducted using magnetic resonance imaging within the outpatient clinic. Results The analysis of serum vitamin D levels within a cohort comprising 59 subjects produced significant observations, indicating that 20.03% of the participants manifested a deficiency in vitamin D and 44.07% exhibited insufficiency in vitamin D levels. There was no observed correlation between serum vitamin D levels and various patient parameters, including age (P = .99), body mass index (P = 0.31), tear size (P = 0.41), cartilage thickness at different locations on the humeral head (superior, middle, inferior, and total) (P = 0.31, 0.40, 0.26, 0.20, respectively), degree of fatty infiltration of the rotator cuff (P = 0.81), and severity of the rotator cuff condition (P = 0.13). A significant positive correlation was established between rotator cuff tear size and both the severity of the rotator cuff condition (P < 0.001) and the degree of fatty infiltration of the cuff (P < 0.001). Conclusion A negative correlation is observed between serum vitamin D levels and various parameters, including tear size, fatty infiltration, cartilage thickness, and the severity of rotator cuff tears within the elderly urban Thai population. To affirm these findings, it is imperative to conduct additional research and integrate vitamin D assessments into the management strategies for aging populations with rotator cuff conditions.

The Needle-and-Knife Technique: A Safe Technique for Anterolateral Portal Placement in Elbow Arthroscopy.

BACKGROUND: Safe and effective portal placement is crucial for successful elbow arthroscopy. Various techniques for anterolateral portal placement in elbow arthroscopy have been described, yet radial nerve injuries are commonly reported. PURPOSE: To report on the technique and safety of anterolateral portal placement by the needle-and-knife method and its clinical applications. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective review was completed of patients who underwent an arthroscopic procedure in the anterior compartment of the elbow and anterolateral portal placement. Patients were evaluated immediately postoperatively and at subsequent visits and were monitored for signs of radial nerve injury. RESULTS: A total of 460 patients met the inclusion criteria, of which 309 (67%) underwent the needle-and-knife technique. There was 1 case (0.3%) of temporary radial nerve palsy. For the remaining 151 patients who underwent anterolateral portal placement by other techniques, there were 2 cases of temporary radial nerve palsy (1.3%). There were no cases of the needle-and-knife technique being unsuccessful or abandoned in lieu of a different technique. Use of the needle-and-knife technique increased over time with experience and practice. Initially, contraindications to this technique included impaired view of the lateral side of the anterior compartment of the elbow caused by severe intra-articular scar (65%), extensive synovitis (10%), or large osteophytes or loose bodies (10%). For the remaining patients (15%) who did not have portals placed via the needle-and-knife technique, alternate techniques were used for teaching purposes. CONCLUSION: The needle-and-knife technique is reproducible and easy to perform by a clinician instructed in its use and trained in elbow arthroscopy. Its main advantage is that it permits the surgeon to safely slide the knife along the lateral supracondylar ridge, releasing the scarred capsule and thereby increasing the available space in which to work. Enlarging the working space inside scarred and contracted elbows cannot be accomplished by distending the capsule.

Joint Contact Changes With Undersized Prosthetic Radial Heads.

OBJECTIVE: To evaluate the effect of intentional undersizing of prosthetic radial head implant diameters on joint contact pressures. METHODS: Eight fresh-frozen cadaveric elbows were aligned in neutral extension and loaded with 100 N using a custom testing apparatus. Radiocapitellar contact pressures were recorded using a Tekscan thin-film pressure sensor. Prosthetic radial head replacement was performed with 2 prostheses: the Anatomic Radial Head and the Evolve Proline Radial Head prostheses. Each design was sized according to the manufacturer's recommendations and then again using 2-mm smaller radial heads. RESULTS: Average and peak pressures were significantly higher with the Evolve than the Anatomic prostheses (P < 0.03 and 0.02, respectively). Peak pressures decreased from 4.2 ± 0.5 MPa to 2.9 ± 0.3 MPa for the Anatomic Radial Heads and from 5.6 ± 0.5 MPa to 3.9 ± 0.6 MPa when the Evolve Radial Heads were undersized by 2 mm. The mean pressures of the Anatomic Radial Heads (1.4 ± 0.1 MPa) did not change significantly with undersizing (1.3 ± 0.1 MPa, P = 0.12), whereas the mean pressures of the Evolve Radial Heads (1.6 ± 0.1 MPa) were significantly reduced with undersizing (1.4 ± 0.1 MPa, P < 0.02). CONCLUSION: Both mean and peak pressures were initially high for the Evolve Radial Head sized based on the short axis diameter and were improved with further undersizing by 2 mm. Peak, but not mean, contact pressures were improved by undersizing the Anatomic prosthesis based on the long axis diameter. CLINICAL RELEVANCE: These findings support the clinical recommendation of some surgeons to undersize the Evolve prosthesis by 2-mm smaller diameter than the current manufacturer's suggestion and give reason to consider doing the same for the Anatomic prosthesis.