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M. Daniel Wongworawat, MD
Assistant Dean, Career Advisement, School of Medicine
School of Medicine
Assistant Chair, Orthopedic Surgery
School of Medicine
Head, Orthopedic Surgery, Hand Surgery
School of Medicine
Professor, Orthopedic Surgery
School of Medicine
Publications    Scholarly Journals--Published
  • Downs DJ, Gregorius S, Wongworawat MD. "Timeliness of appropriate antibiotics in hand infections." Clinical Orthopaedics and Related Research . (2007): -. ( 10/2007 )
    The objective of this study was to determine if a significant difference in time to appropriate antibiotic treatment exists between methicillin resistant staphylococcus species (MRS) and non-MRS hand infections. A retrospective chart review based on ICD-9 codes was performed. Patients were included in the study only if they had a culture positive hand infection and received antibiotic treatment. Age, gender, time of presentation, time of receiving any antibiotic, time of final culture results, and time of receiving culture appropriate antibiotics were recorded. One-hundred ten patients were identified. Thirty-two patients met inclusion criteria. There were eighteen males and fourteen females. Average age was 39.1 years (6 months to 72 years). The prevalence of MRS was thirty-four percent. Data was analyzed using the Log-Rank test. The difference in time to any antibiotic (mean: non-MRS 0.26 days, MRS 0.63 days) was not significant, p = 0.1397. The difference in time to appropriate antibiotics (mean: non-MRS 0.39 days, MRS 2.19 days) was significant, p = 0.0002. A significant delay in receiving appropriate antibiotics exists between MRS and non-MRS hand infections in this patient set. This study supports efforts to develop rapid detection MRS tests as well as early empiric coverage for community acquired methicillin resistant staphylococcus species in hand infections.
  • Cullan DB, Wongworawat MD. "Sterility of the surgical site marking between the marker and the epidermis." Journal of the American College of Surgeons 205.2 (2007): 319-321. ( 8/2007 )
    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.
  • Downs DJ, Gregorius S, Wongworawat MD.. "Timeliness of appropriate antibiotics in hand infections." Clinical Orthopaedics and Related Research 461. (2007): 17-19. ( 8/2007 )
    We retrospectively reviewed the charts of 110 patients to determine if there was a difference in the time to appropriate antibiotic treatment between methicillin-resistant staphylococcus aureus (MRSA) and non-MRSA hand infections. Patients were included in the study only if they had a culture-positive hand infection and received antibiotic treatment. Thirty-two patients (18 male and 14 female) with an average age of 39.1 years (range, 6 months-72 years) met the inclusion criteria. We recorded patient age, gender, date of presentation, time to receiving any antibiotic, time to final culture results, and time to receiving culture-appropriate antibiotics. The overall prevalence of MRSA infection was 34%. When compared to those with non-MRSA infections, patients with MRSA hand infections experienced a substantial delay in receiving appropriate antibiotics.
  • Keese GR, Boody AR, Wongworawat MD, Jobe CM.. "The accuracy of the saline load test in the diagnosis of traumatic knee arthrotomies." Journal of Orthopaedic Trauma 21.7 (2007): 442-443. ( 8/2007 )
    OBJECTIVES:: When open joint injury is suspected in a knee laceration, the saline load test has been recommended as a diagnostic modality, especially in small wounds, where inspection and palpation cannot confirm joint violation. The goals of this study are: 1) to correlate fluid volume needed for positive diagnosis with demographic factors, 2) to assess the sensitivity of using the commonly recommended volume of 50 mL, and 3) to identify the minimum fluid volume necessary to obtain 95% sensitivity. DESIGN:: Prospective cohort. SETTING:: University medical center. PATIENTS/PARTICIPANTS:: Thirty consecutive patients scheduled for elective outpatient knee arthroscopy were prospectively enrolled. Exclusion criteria include history of open traumatic injury, presence of active infection, or limited range of motion as evidence of arthrofibrosis. INTERVENTION:: A standard lateral parapatellar portal was made with a no. 11 blade scalpel, and a 5.8 mm diameter cannula-trochar was inserted and withdrawn to create a standard arthrotomy size of 26.4 mm. Using an 18-gauge needle, saline was injected through a separate lateral suprapatellar site until outflow was noted. MAIN OUTCOME MEASUREMENTS:: Upon fluid outflow, the volume of injected saline was recorded. RESULTS:: The volume injected until outflow was similar between men and women (P = 0.87). No correlation was observed between the volume injected and age (P = 0.85), height (P = 0.18), weight (P = 0.46), and body mass index (P = 0.91). Injection of 50 mL successfully identified only 46% of known arthrotomies. A saline load of 194 mL was required to achieve 95% sensitivity. CONCLUSIONS:: For small lacerations around the knee, saline loads of less than 194 mL are of questionable sensitivity, and surgeons should not use the saline load test to rule out open knee injuries.
  • Wongworawat MD, Jones SG. "Influence of finger jewelry on hand sanitization procedures and residual bacterial contamination." Infection Control and Hospital Epidemiology 28.3 (2007): 351-353. ( 3/2007 )
    BACKGROUND: Previous studies, conducted before widespread use of scrubless, alcohol-based hand sanitizers, demonstrated increased residual bacterial counts after hand hygiene on hands with jewelry. OBJECTIVE: To compare the impact of finger rings on the effectiveness of scrubless and water-aided alcohol-based hand sanitization methods with that of povidone-iodine scrub. DESIGN: Randomized, controlled study.Setting. University hospital.Participants. Sixty volunteer subjects from a pool of perioperative staff and medical students. INTERVENTION: After recruitment, participants wore a ring on one hand and no ring on the other hand. They were randomly assigned to perform hand hygiene with a povidone-iodine scrub, an alcohol wash, or a waterless alcohol-chlorhexidine lotion (n=20 subjects per method). After subjects completed hand hygiene, gloves were placed on their hands by means of sterile methods, and a "glove juice" technique was used to obtain samples for culture. The number of colony-forming units in each culture was counted, and the data were compared. RESULTS: There was no significant difference in the number of bacteria between hands with and hands without rings for the groups that used alcohol wash or alcohol-chlorhexidine lotion. However, for the povidone-iodine group, the number of bacteria on hands with rings was greater than the number on hands without rings (P
  • Keese GR, Wongworawat MD, Frykman G. "Clinical significance of the palmaris longus tendon on the pathophysiology of carpal tunnel syndrome." Journal of Hand Surgery British 31.6 (2006): 657-660. ( 12/2006 )
    Carpal tunnel syndrome is associated with increased intracarpal canal pressure. The effect of tendon loading on intracarpal canal pressures is documented in biomechanical studies. Palmaris longus loading in wrist extension induces the greatest absolute increase in intracarpal canal pressure. Despite this fact, the palmaris longus is not yet a proven independent risk factor for the development of carpal tunnel syndrome. The purpose of this prospective clinical study was to assess and quantify the association between the presence of a palmaris longus tendon and carpal tunnel syndrome. Thirty-six carpal tunnel subjects with bilateral disease were compared with 36 controls. Each subject was clinically examined for the presence of the palmaris longus tendon. The prevalence of palmaris longus agenesis was significantly lower in the carpal tunnel group. The palmaris longus tendon is a strong independent risk factor for carpal tunnel syndrome.
  • Boody AR, Wongworawat MD. "Accuracy in the measurement of compartment pressures: a comparison of three commonly used devices." Journal of Bone and Joint Surgery, American 87.11 (2005): 2415-2422. ( 11/2005 )
    Background: In situations where accurate physical diagnosis is inconclusive, an objective method to measure compartment pressure can aid in the diagnosis of compartment syndrome. Studies have compared measurement devices to each other without accurate determination with a gold standard. Our purpose was to devise a reproducible in vitro compartment pressure model and to compare commonly used devices for objective pressure measurement to determine accuracy. Methods: Using a graduated cylinder to generate a known pressure, freshly harvested ovine muscle was placed into a chamber for testing. The cylinder was incrementally filled with saline (in 55 steps), and measurements of tissue pressures were obtained using the Stryker Intracompartmental Pressure Monitor System, the arterial line manometer, and the Whitesides apparatus. Each was tested with straight, side-port needles, and slit-catheters?9 setups. Five trials with each setup were done. Control pressures were calculated based on the heights of the saline column (test range: 0.13 to 10.80 kPa). Multiple regression analysis was used to compare measured tissue pressures versus calculated control pressures. Results: Most methods had excellent correlation (R2 > 0.95) between calculated and measured pressures. The arterial line with slit-catheter showed the best correlation (R2 = 0.9978) and the Whitesides apparatus with side-port had the worst (R2 = 0.9115). Furthermore, the Stryker system with side-port needle had the least constant bias (+0.06 kPa). Straight needles tended to overestimate pressures. Two of the three needle configurations with the Whitesides method overestimated pressures. 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. The arterial line is the most accurate manometer. The Stryker device is also very accurate. The Whitesides manometer apparatus lacks the precision needed for clinical use. Clinical Relevance: When physical examination is inconclusive, accurate measurement of compartment pressures can aid in timely management and minimize patient morbidity. Measurement should be done using the most accurate technique available.
  • Hassinger SM, Harding G, Wongworawat MD. "High-pressure pulsatile lavage propagates bacteria into soft tissue." Clinical Orthopaedics and Related Research 439.x (2005): 27-31. ( 10/2005 )
    Initial wound treatment is critical in the treatment of open fractures, contaminated wounds, and abscesses. Ample evidence suggests that high-pressure pulsatile lavage damages bone structure and disrupts soft tissue. We compared the depth of penetration and amount of retention of bacteria in contaminated soft tissue subjected to one of two lavage methods: high-pressure pulsatile and low-pressure gravity flow. Fresh ovine muscle was harvested, contaminated with fluorescently stained Staphylococcus aureus, and subjected to lavage treatment. Specimens in each lavage method group were subdivided based on orientation across or in line with the muscle fibers. High-pressure lavage causes increased depth of bacterial penetration (across: 3,835 microns; in line: 4,220 microns) when compared with low-pressure lavage (across: 1,680 microns; in line: 2,095 microns). Furthermore, both high pressure treatment groups had higher numbers of retained bacteria as counted in 50 microm 7,500 microns 5 microns sections of tissue after lavage (across: 197; in line: 188) when compared with the low-pressure groups (across: 94; in line: 40). These results show that high-pressure pulsatile lavage causes deeper penetration of bacteria and results in greater bacterial retention in soft tissue when compared with low-pressure lavage.
  • Boyd JI, Wongworawat MD. "High-pressure pulsatile lavage causes soft tissue damage." Clinical Orthopaedics and Related Research 427.0 (2004): 13-17. ( 10/2004 )
    Irrigation and debridement can be a source of iatrogenic injury in open fracture treatment. Although high-pressure pulsatile lavage has been shown to cause considerable damage to bone, little has been written about its effects on soft tissue. The purpose of this study is to quantify and compare the damages on soft tissue caused by high-pressure pulsatile lavage and low-pressure lavage. Forty specimens of fresh ovine muscle were collected and subjected to high-pressure pulsatile lavage or low-pressure lavage, with the delivery orientation being across or in line with the muscle fibers. Ten additional specimens were used as controls. The results show that high-pressure pulsatile lavage causes considerable soft tissue penetration of particulate markers (across, 4.7 mm; in line, 15.6 mm) when compared with low-pressure lavage (across, 0.5 mm; in line, 0.7 mm). Furthermore, all specimens subjected to high-pressure pulsatile lavage showed gross tissue disruption. Fifteen additional samples were obtained to measure cellular death. This was observed at a deeper level for high-pressure pulsatile lavage (median depths: across, 1210 microm; in line, 1335 microm), which was approximately twice that of low-pressure lavage (across, 485 microm; in line, 682 microm). These results show that high-pressure pulsatile lavage penetrates and disrupts soft tissue to a deeper level than low-pressure lavage, causing considerable gross and microscopic tissue disruption.
  • Schramm JM, Nguyen M, Wongworawat MD.. "The safety of percutaneous trigger finger release." Hand. 2008;3:44-46. ( 3/2008 - Present )
    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.
  • Schramm JM, Nguyen M, Wongworawat MD, Kjellin I.. "Does thumb immobilization contribute to scaphoid fracture stability?." Hand. 2008, 3:41-43.  ( 3/2007 - Present )
    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.
  • Jones SG, Wongworawat MD. "Influence of finger jewelry on hand sanitization procedures and residual bacterial contamination." Infectious Control and Hospital Epidemiology 2007;28(3);35103. ( 3/2007 - Present )
    Objective: Previous studies have demonstrated increased residual bacteria on the hand after sanitization in the presence of jewelry. These studies were done before recent evidence has shown the efficacy of ?scrubless? alcohol based hand sanitization. In light of the new techniques, the authors aim to re-examine the impact of wearing rings on scrub effectiveness. Design: Randomized controlled study. Setting: University hospital Participants: Sixty subjects were used for the study, drawn from volunteers of the perioperative staff and medical students. Intervention: Institutional review board approval was obtained. After recruitment, participants wore one ring on either hand. They were randomly assigned to either scrub with a povidone/iodine scrub, an alcohol wash, or waterless alcohol/chlorhexedine lotion (n = 20 for each method). After completing the scrub process, participants were gloved in a sterile fashion, and a glove-juice technique was used to obtain samples for culture. The number of colony forming units was counted for each culture and the numbers compared. Results: There was no difference in number of bacteria on the hands between the ringed and non-ringed groups for the alcohol wash and alcohol/chlorhexedine lotion groups. However, for the povidone/iodine group there were greater numbers of bacteria on ringed hands than non-ringed hands (p < 0.05). The alcohol/chlorhexedine group also showed the lowest bacterial count, whether or not rings were present (p < 0.01). Conclusions: Ring wear does not negatively impact hand sanitization procedures when using alcohol-based preparations. Alcohol/chlorhexedine waterless application produced the most reduction in bacterial count.
  • Keese GR, Wongworawat MD, Frykman G. "Clinical significance of the palmaris longus tendon on the pathophysiology of carpal tunnel syndrome." Journal of Hand Surgery, British.  ( 12/2006 - Present )
    Carpal tunnel syndrome is associated with increased intracarpal canal pressure. The effect of tendon loading on intracarpal canal pressures is documented in biomechanical studies. Palmaris longus loading in wrist extension induces the greatest absolute increase in intracarpal canal pressure. Despite this fact, the palmaris longus is not yet a proven independent risk factor for the development of carpal tunnel syndrome. The purpose of this prospective clinical study was to assess and quantify the association between the presence of a palmaris longus tendon and carpal tunnel syndrome. Thirty-six carpal tunnel subjects with bilateral disease were compared with 36 controls. Each subject was clinically examined for the presence of the palmaris longus tendon. The prevalence of palmaris longus agenesis was significantly lower in the carpal tunnel group. The palmaris longus tendon is a strong independent risk factor for carpal tunnel syndrome.
  Books and Chapters
  • Nelson SC, Wongworawat MD. Tolerances: An Orthopaedic Reference Manual. Loma Linda, CA: Loma Linda University Press, 2005. ( 10/2005 )
  Non-Scholarly Journals
  • Wongworawat MD"A real pain in the wrist: Carpal tunnel syndrome." The Sun -- San Bernardino County 28 04 2005: B5 - B5 ( 4/2005 )