The Effect of Timing Between Traumatic Flexor Tendon Injury of the Hand and Surgical Intervention on Repair Failure Rates.

Flexor tendon injuries of the hand, especially in zone II, pose a challenge for hand surgeons because of the region's intricate pulley mechanism and local avascularity, and post-surgical complications such as repair failure are not uncommon. One proposed predictor of outcomes following flexor tendon repair has been timing of surgery from initial injury. However, the effect of the timing of flexor tendon repair on failure rates remains controversial and understudied. The purpose of this study was to compare the failure rates of zone II flexor tendon repairs in patients at various time intervals from onset of injury. A retrospective chart review was conducted using data from hand surgery specialists at our level 1 trauma center from January 1, 2010, through May 31, 2020. This retrospective review included 407 zone II flexor tendon repairs. The primary outcome was failure of repair. Among 407 flexor tendon repairs, there were 12 reported repair failures. The failure rate was 2.9%. In the non-failure group, the mean number of days between the date of injury and the date of surgery was 7±13 days. For the failure group, this value was 14±17 days. Repairs occurring within 14 days had a failure rate of 2.3%, while repairs occurring beyond 14 days had a failure rate of 7.7%. This study demonstrates that there is a benefit to repairing the tendon within a 14-day window, as evidenced by a lower failure rate. More research is required to determine if other complications and overall health of the hand are also improved when a repair is performed in a more expedient manner. [Orthopedics. 2024;47(2):113-117.].

Ultrasound Measurement Error and Its Implications for Carpal Tunnel Syndrome Diagnosis.

Background: Ultrasound (US) measurement of the cross-sectional area (CSA) of peripheral nerves has been validated as a method for diagnosing peripheral nerve compression; however, the accuracy of US measurements and variation among examiners have not been well established. The purpose of this study was to determine the percent error from a known measurement among multiple US examiners using a gel phantom model. Methods: A US phantom gel, with 2 embedded, premeasured cylindrical objects, was constructed, and 9 residents, fellows, and attending physicians with upper-extremity US experience were recruited to use US to measure the CSA of each object. Percent error was calculated based on the premeasured value of each object, which was measured using digital calipers, and was calculated using the formula for CSA of a cylinder (A = pi × r2) prior to insertion into the gel phantom. Results: The mean percent error for examiners' CSA measurements was 9.0% ± 4.7% (range, 1.6%-17.0%). There was a greater mean percent error for the smaller measured object compared with the larger one. There was a very minimal decline in percent error with increase in years of training experience (slope = -0.029, R2 = 0.0002). Conclusion: This study demonstrates that US examiners were able to measure CSAs of premeasured objects with approximately 10% error. When considering the use of US for the diagnosis of carpal tunnel syndrome, a cutoff value of 10 mm2 is often used, and therefore in cases where measurements are within 10% of the diagnostic threshold, caution should be exercised in interpreting the results.

Study of hair surface energy and conditioning.

A new test method has been developed to determine surface energy of hair fibers through measurements of contact angles at two hair/liquid interfaces. By measuring changes in surface energy of the same hair fiber before and after a cosmetic treatment, effects of active ingredients and the performance of tested formulations can be evaluated.The establishment of the method is based on Fowkes theory (1,2) described with two components, a dispersive and a non-dispersive component. The non-polar liquid used in this study was diiodomethane, and the polar liquid was benzyl alcohol. A Kruss 100 Tensiometer was used to measure contact angles of hair fibers. Virgin dark brown and regular bleached hairs were treated with selected conditioner formulations. Reductions in combing forces of hair tresses before and after respective treatments were correlated with decreases in average surface energy of hair fibers obtained from the corresponding tresses.Experimental results indicate that the average surface energy of hair fibers treated with conditioners decreases and the hydrophobicity of the hair surface increases, the results correlate well with the reduction in combing forces after respective treatments. This research work provides a new methodology to evaluate/screen conditioning performance of hair care ingredients and formulations for development of better products.

Study of hair shine and hair surface smoothness.

A new hair visual appearance measurement system called SAMBA from Bossa Nova Technologies (Venice, CA) has been employed to measure effects of cosmetic treatments on hair shine and surface smoothness of different types of hair samples. Experimental procedures for evaluations of shine value and surface cuticle angle of hair samples treated with rinse-off products (shampoo or/and conditioner) have been successfully established and applied. We demonstrated that hair spray and conditioner formulas containing PPG-3 benzyl ether myristate (PBEM) (1) showed great performance on shine enhancement for hairs with light and medium colors. Instrumental measurement of shine values was also conducted to compare different commercial shampoo and conditioner products. This study showed reliable utility of SAMBA system and demonstrated the shine enhancement of PBEM in hair care.

Evaluation of hair humidity resistance/moisturization from hair elasticity.

Average water regain and hair elasticity (Young's modulus) of virgin dark brown and bleached hair fibers under different relative humidity (RH) were determined. It is observed that hair water regain increases linearly with an increase in RH in the range of 40-85%; and the remaining percent of hair elasticity decreases linearly with an increase in RH in the range of 50-80%. Therefore, measurements of average hair elasticity at 50% and 80% RH, respectively, under various equilibrium times before and after cosmetic treatments can be used to evaluate effects of cosmetic treatments on water adsorption behavior of hair-improvement in hair humidity resistance or enhancement in hair moisture uptake. A Hair Humidity Resistance Factor (H(2)RF) has been defined. If R(2)HF > 1, the product improves hair humidity resistance-anti-frizz; if R(2)HF < 1, the product enhances hair water adsorption; when R(2)HF approximately 1, the product has no significant effect on hair water adsorption behavior. This method was applied to evaluate anti-frizz performance of several shampoo formulations containing Polyquaternium-10, or Polyquaternium-70, or Polyquaternium-67, or Guar Hydroxypropyltrimonium Chloride. It was found PQ-70 shampoo showed the highest H(2)RF value and the best anti-frizz performance among these tested shampoos. The results were consistent with those obtained from Image Analysis.

A new multifunctional, shine-enhancing emollient: PPG-3 benzyl ether myristate.

A new emollient ester--Crodamol STS (INCI name: PPG-3 Benzyl Ether Myristate) has been developed and characterized. This special non-volatile emollient is safe to use and provides silicone-like feel and multiple cosmetic functionality. It is a liquid with a viscosity about 100 cps at room temperature. It has a high refractive index--1.4696, which enhances hair shine, contributes to high gloss in lip products, and reduces whitening effect of fatty alcohols and silica in anti-perspirants/deodorants applications. This emollient has high solubility of UV filters, low skin-spreading factor, and good pigment wetting behavior, which are preferable in sunscreen and make-up formulas to enhance the pigment localization and improve SPF value. In this paper, the chemical structure, physical properties, and various cosmetic applications of the emollient will be discussed. Especially, an objective hair shine (luster) test method (color image analysis) has been established and applied to study the enhancement in hair shine by Crodamol STS in hair spray and hair gel formulations. The objective measurements in hair shine showed good agreement with the results obtained from subjective evaluations. The substantivity of Crodamol STS on hair surface, which was delivered from a rinse-off cream, was also determined by a solvent extraction method.