Craig S. Phillips

Occipitocervical neutral position. Possible surgical implications.

STUDY DESIGN The study defines the occipitocervical neutral position using cervical radiographs from 30 subjects. OBJECTIVE To identify reproducible radiographic measures of the occipitocervical neutral position that can be used during surgery to optimize fusion position. SUMMARY OF BACKGROUND DATA When performing rigid internal fixation of the occiput to the cervical spine, the ability to determine that the occiput is in a neutral position in relation to the cervical spine is important. Currently, no objective radiographic measures for the occipitocervical neutral position exist. METHODS Thirty flexion, extension, and neutral lateral cervical spine radiographs radiographs interpreted as normal by an experienced radiologist were studied. The occipitocervical angle and occipitocervical distance were defined and calculated. Two investigators, an orthopedic resident and an experienced orthopedic spine surgeon, measured the occipitocervical angle and occipitocervical distance independently on all radiographs in a blinded manner. Correlation coefficients were obtained to determine interobserver reliability. RESULTS The mean occipitocervical angles were 24.2 degrees, 44.0 degrees, and 57.2 degrees in flexion, neutral, and extension, respectively. The mean occipitocervical distances were 21.5 mm in neutral, 28.0 mm in flexion, and 14.8 mm in extension. The differences in the occipitocervical angle and occipitocervical distance in neutral, flexion, and extension were statistically significant (P < 0.05 and < 0.001, respectively). There were no significant interobserver differences in any of the measurements. CONCLUSIONS The radiographic measures of the occipitocervical neutral position reported in this study are reliable, repeatable, and simple to determine on routine lateral radiographs. These measurements should be a valuable intra-operative tool for achieving occipitocervical fusion in appropriate alignment.

Mechanical analysis of the palmar aponeurosis pulley in human cadavers

The anatomy of the palmar aponeurosis pulley has been well described, but its biomechanical function is not as well characterized. This study describes the functional importance of the palmar aponeurosis pulley by using efficiency parameters. We obtained data by generating load, excursion, and work efficiencies in the intact pulley system and compared these to the efficiencies obtained after sectioning the palmar aponeurosis pulley alone and in combination with the proximal annular pulleys. The variability associated with comparisons between different fingers and hands was therefore diminished. Sectioning the palmar aponeurosis pulley alone did not significantly change any of the efficiency parameters. When the palmar aponeurosis pulley was sectioned in combination with either or both of the proximal annular pulleys (A1, A2) there was a significant decrease in excursion efficiency. Only after all three proximal pulleys were sectioned did the load efficiency increase and the work efficiency decrease significantly. These findings prove that the palmar aponeurosis pulley in combination with the proximal annular pulleys acts to decrease the tendency to bowstringing around the metacarpophalangeal joint. The increased load efficiency is probably the result of a decrease in friction and counteractive forces generated by the integrated fibers of the intact palmar aponeurosis pulley. Change in work is due not only to an increase in excursion, but also to the increased resistance that results from the acute angulation that the tendon must endure as it follows behind the remaining pulleys during flexion. Intergroup comparisons show a significant contribution by the palmar aponeurosis pulley. This study demonstrates a significant biomechanical role for the palmar aponeurosis pulleys and suggests that it be considered similar to the annular and cruciate flexor tendon pulleys in importance.

Vascular problems of the upper extremity: a primer for the orthopaedic surgeon.

&NA; A focused history and thorough physical examination, combined with a working knowledge of the normal vascular anatomy, can help identify most vascular abnormalities of the upper extremity. Technologic improvements now allow accurate diagnosis by noninvasive methods. Most abnormalities can be categorized into one of five major diagnostic groups: traumatic, compressive, occlusive, tumoral (malformation), and vasospastic. Behavioral modifications and pharmacologic agents may improve symptoms. Appropriately selected surgical candidates often experience pain relief and functional improvement.

A biomechanical study of the flexor digitorum superficialis: Effects of digital pulley excision and loss of the flexor digitorum profundus

Many reports have been devoted to characterizing the significance of the pulleys for the flexor digitorum profundus (FDP). However, no comparable work has been published on the flexor digitorum superficialis (FDS). This study characterized the FDS in a human cadaver model. Eleven fresh-frozen cadaver hands were used. By using a tensiometer, data were gathered for tendon excursion, tendon load, and work of flexion. Changes in efficiency were caused by excision of annular pulleys A1, A2, A3, and the palmar aponeurotic pulley. We also measured the effect of FDP excision on FDS efficiency. Sectioning of the A2 and A3 pulleys together caused statistically significant losses of efficiency in all three parameters (work, load, and excursion). When the FDP was removed from a finger with an intact pulley system, losses in both work and excursion efficiencies were significant. Removing the FDP while cutting different pulleys caused significant decrease in FDS excursion efficiency. We conclude that A2 and A3 are the most important pulleys for maintaining normal FDS function, and that the presence of the FDP in the digital sheath is essential for optimal FDS excursion efficiency.

Risk Factors for Complications Following Open Reduction Internal Fixation of Distal Radius Fractures

PURPOSE A national surgical database was used to determine risk factors for complications in patients undergoing open reduction internal fixation (ORIF) for distal radius fractures. METHODS The American College of Surgeons National Surgical Quality Improvement Program database for the 2006-2012 years was queried to identify all patients who underwent an ORIF of a distal radius fracture based on Current Procedural Terminology codes 25607, 25608, or 25609. The database is a statistically representative sample of prospectively collected perioperative surgical data from hospitals primarily in the United States. Demographics, comorbidities, preoperative laboratory values, and 30-day complications were compared between the patient groups with and without a postoperative complication. Multivariate analysis was performed to identify patient characteristics and comorbidities that were independently associated with early postoperative complications. RESULTS This retrospective analysis identified 3,003 patients who underwent an ORIF of the distal radius over 7 years. The number of patients with a complication within 30 days after surgery was 62 (2%), totaling 90 complications. Incidence of return to the operative room for the entire study population was 1.1%. Multivariate analysis, adjusting for confounding variables, showed that patients with a complication were more likely to have hypertension, congestive heart failure, preoperative chemotherapy or radiotherapy, longer operating time, and manifest preoperative impairment in independent living. CONCLUSIONS Approximately 2% of patients sustained a complication within 30 days following ORIF of a distal radius fracture. Recognition of the risk factors may help avoid complications in the identified high-risk patients. TYPE OF STUDY/LEVEL OF EVIDENCE Prognostic II.

Diagnosis and treatment of post-traumatic medial and lateral elbow ligament incompetence

Elbow instability may occur secondary to soft tissue or bony injuries. Predictable patterns of instability do occur. Identification of disrupted osseous or ligamentous constraints allows for an algorithmic and predictable treatment plan. Maintaining a high index of suspicion allows early recognition and treatment of elbow instability. Treatment based on recognized principles is the key to preventing recurrent instability and late arthrosis while maintaining functional elbow motion.

THE EFFECTS OF FOREARM ROTATION ON THREE WRIST MEASUREMENTS: RADIAL INCLINATION, RADIAL HEIGHT AND PALMAR TILT

The purpose of this study was to evaluate and quantify the effects of forearm rotation on radial inclination, radial height and palmar tilt. Seventeen arms, nine cadaveric and eight volunteer, were examined using a radiolucent device that allowed for the controlled rotation of each arm. Lateral and posterior-anterior X-rays were taken at 5 degrees increments which were then measured by two physicians using standardised protocol. The results revealed that all three measurements were significantly affected by forearm rotation with forearm supination increasing the apparent measurements and forearm pronation decreasing the apparent measurements. This relationship was well characterised by linear trend modelling such that forearm pronation of 10 degrees decreased the apparent radial inclination, radial height and palmar tilt by 2.8 degrees , 1.6 mm and 4.4 degrees , respectively. This study demonstrates that forearm rotation is an important factor in the accurate evaluation of wrist measurements, and that slight rotation of the wrist during radiographic imaging may significantly alter management decisions given established surgical criteria.

Biomechanical changes of cadaveric finger flexion: The effect of wrist position and of the transverse carpal ligament and palmar and forearm fasciae

This study was designed to investigate whether the position of the wrist or sectioning of the transverse carpal ligament (TCL), as well as the palmar fascia and forearm fascia, modifies the biomechanical behavior of the finger flexion, as defined by changes of excursion, load (force), and work of the flexor tendons. The parameters were measured in fresh-frozen cadaver hands with the wrist in 30 degree extension, neutral, and 30 degree flexion, before and after division of the TCL. Having the wrist in extension improved excursion efficiency, whereas flexing the wrist produced the opposite effect, with a 16% decrease in excursion efficiency after division of the TCL. Change in excursion efficiency between the intact and cut TCL was 8% in the flexed position, 5% in the neutral position, and 0.3% in the extended position. Change in load efficiency between intact and cut TCL was 11% in the flexed position, 6% in the neutral position, and 0% in the extended position. Change in the work efficiency between intact and cut TCL groups was noted most with the wrist in the flexed position (13%), compared to a small change (3%) in neutral wrist position and no change in wrist extension. A significant decrease in the excursion efficiency of the flexor tendons was demonstrated when the wrist was in the flexed position. Any increase in the excursion of the flexor tendons could clinically result in decreased grip strength when the wrist is flexed. Furthermore, the effects of TCL division were not significant when wrist position was in extension.

The flexor synovial sheath anatomy of the little finger : a macroscopic study

Anatomy texts describe the flexor synovial sheath of the little finger as extending proximally into the palm to join with the ulnar bursa in 80% of cases. Based on this, one would expect frequent extension of little finger flexor synovial sheath infections into the forearm. Methylene blue injection followed by open tenogram was used to define the anatomy of the flexor synovial sheath of the little finger in 60 cadaver hands. In 27 hands, the flexor synovial sheath extended proximally from the bony profundus tendon insertion to terminate at the palmar aponeurosis pulley. A stricture of varying length separated the flexor synovial sheath from the more proximal ulnar bursa. In 19 hands, the flexor synovial sheath was continuous with the ulnar bursa, conforming to the conventional textbook description. In 14 hands, the flexor synovial sheath stopped at the proximal border of the A1 pulley. An inconsistent defect from 1 to 10 mm was noted. The clinical implications of these findings suggest that many little finger flexor synovial sheath infections, when caught early and after careful physical examination, need only be managed by drainage at the distal palmar level.