Acetabular roof arc angles and anatomic biomechanical superior acetabular weight bearing area

Background:

Acetabular fracture involves whether superior articular weight bearing area and stability of the hip are assessed by acetabular roof arc angles comprising medial, anterior and posterior. Many previous studies, based on clinical, biomechanics and anatomic superior articular surface of acetabulum showed different degrees of the angles. Anatomic biomechanical superior acetabular weight bearing area (ABSAWBA) of the femoral head can be identified as radiographic subchondral bone density at superior acetabular dome. The fracture passes through ABSAWBA creating traumatic hip arthritis. Therefore, acetabular roof arc angles of ABSAWBA were studied in order to find out that the most appropriate degrees of recommended acetabular roof arc angles in the previous studies had no ABSAWBA involvement.

Materials and Methods:

ABSAWBA of femoral head was identified 68 acetabular fractures and 13 isolated pelvic fractures without unstable pelvic ring injury were enrolled. Acetabular roof arc angle was measured on anteroposterior, obturator and iliac oblique view radiographs of normal contralateral acetabulum using programmatic automation controller digital system and measurement tools.

Results:

Average medial, anterior and posterior acetabular roof arc angles of the ABSAWBA of 94 normal acetabulum were 39.09 (7.41), 42.49 (8.15) and 55.26 (10.08) degrees, respectively.

Conclusions:

Less than 39°, 42° and 55° of medial, anterior and posterior acetabular roof arc angles involve ABSAWBA of the femoral head. Application of the study results showed that 45°, 45° and 62° from the previous studies are the most appropriate medial, anterior and posterior acetabular roof arc angles without involvement of the ABSAWBA respectively.     

Does Thumb Immobilization Contribute to Scaphoid Fracture Stability?

Immobilization protocols for nondisplaced scaphoid fractures have included the elbow, wrist, and thumb. This study attempts to demonstrate whether or not immobilization of the thumb makes a difference in preventing motion at the scaphoid fracture site. Using six fresh frozen forearm specimens, a transverse waist scaphoid fracture was created through a dorsal approach. Metallic markers were imbedded on either side of the fracture. Sutures were secured to the flexor pollicus longus (FPL) and extensor pollicus longus (EPL). Each specimen was loaded in extension and flexion by attaching 50-g weights to the EPL and FPL, first with no casting, then with a short arm cast, and finally a short arm thumb spica cast. Angulation and displacement at the fracture site were measured in the coronal, sagittal, and axial planes utilizing image reconstructions from computed tomography. One-way ANOVA with repeated measures and Tukey–Kramer multiple comparison test post hoc analysis were used for statistical evaluation. There was no significant difference in fracture angulation or rotation between spica and short arm casts. There was a significant difference in angulation and rotation in all three planes when comparing between casting and no casting, p < 0.05. In our cadaveric model, wrist immobilization is crucial for nondisplaced scaphoid waist fractures, and short arm casting was just as effective as thumb spica casting in preventing fracture displacement.     

Accuracy in the measurement of compartment pressures: a comparison of three commonly used devices

BACKGROUND: In situations in which accurate physical diagnosis is inconclusive, an objective method for measuring compartment pressure can aid in the diagnosis of compartment syndrome. Previous studies have compared measurement devices with each other but not with an accurately determined gold standard. The purpose of the present study was to devise a reproducible in vitro model of compartment pressure and to compare commonly used measurement devices in order to determine their accuracy. METHODS: With a graduated cylinder being used to generate a known pressure, freshly harvested ovine muscle was placed into a chamber for testing. The cylinder was incrementally filled with saline solution (in fifty-five steps), and measurements of tissue pressure were obtained with use of the Stryker Intracompartmental Pressure Monitor System, an arterial line manometer, and the Whitesides apparatus. Each device was tested with a straight needle, a side-port needle, and a slit catheter, for a total of nine setups in all. Five trials were done with each setup. Control pressures were calculated on the basis of the height of the saline solution column (test range, 0.13 to 10.80 kPa). Multiple regression analysis was used to compare measured tissue pressures with calculated control pressures. RESULTS: Most methods demonstrated excellent correlation (R2> 0.95) between calculated and measured pressures. The arterial line manometer with the slit catheter showed the best correlation (R2= 0.9978), and the Whitesides apparatus with the side-port needle showed the worst (R2= 0.9115). Furthermore, the Stryker system with the side-port needle demonstrated the least constant bias (+0.06 kPa). Straight needles tended to overestimate pressure. Two of the three needle configurations involving the Whitesides apparatus overestimated pressure. The data for the Whitesides methods had the highest standard errors, showing clinically unacceptable scatter. CONCLUSION: Side-port needles and slit catheters are more accurate than straight needles are. The arterial line manometer is the most accurate device. The Stryker device is also very accurate. The Whitesides manometer apparatus lacks the precision needed for clinical use.     

The Safety of Percutaneous Trigger Finger Release

This study attempted to determine the safety of percutaneous release of trigger fingers, with particular attention given to border digits and the thumb. We performed percutaneous release of the A1 pulley in six fresh frozen cadaveric hands utilizing established surface landmarks. After freezing all specimens, we performed cross-sections at the A1 pulley, avoiding dissection of soft tissues, which could alter the natural position of the digital nerves. There was no difference in the distance from the needle tract to the neurovascular bundle when comparing between digits, and the closest distance was 2.7 mm. There was no significant difference between the needle tract and the radial and ulnar digital nerves. Based on our findings, percutaneous trigger finger release can safely be performed on all digits, including the thumb, small fingers, and index fingers.     

Sterility of the surgical site marking between the ink and the epidermis

BACKGROUND: To prevent wrong-site surgery, multiple organizations have endorsed the practice of signing the operative site with an indelible marker. Potential contamination of the surgical field and the inability to prepare the area under the ink film raises concerns. The purpose of this study was to determine if the use of preoperative site marking affects the sterility of the surgical field. STUDY DESIGN: After institutional review board approval, 30 consecutive patients scheduled to undergo elective upper extremity surgery by the same surgeon were included. For each patient, surgical marking according to Joint Commission on Accreditation of Healthcare Organizations guidelines were placed on more than half of the planned incision site, and the other half was left unmarked. The patients then underwent routine surgical preparation. The skin was incised, starting from the unmarked side and continuing to the marked aspect. Cultures were obtained by swabbing the skin edges: one from the unmarked side and one from the marked side. After blood agar plating, cultures were incubated for 72 hours and analyzed by a blinded observer. RESULTS: All cultures were negative, regardless of swab site (unmarked or marked location). CONCLUSIONS: The practice of surgical site marking does not increase the risk of operative field contamination.