Are Two- and Three-Dimensional Computed Tomographic Scan Measurements of Tibial Tubercle-Trochlear Groove Distance Equivalent? A Comparative Study.

Background: Accurate planning for patellar instability correction is important in obtaining good post-operative outcome. The main challenge in the current two-dimensional (2-D) computed tomographic (CT) scans method is the difficulty in choosing reliable bony landmarks. This study aimed to compare the reliabilities between the 2-D and three-dimensional (3-D) methods of measuring tibial tubercle-trochlear groove (TT-TG) distance. We hypothesize that the proposed 3-D method will result in measurements with narrower error margin, providing higher reliability and accuracy. Materials and Methods: We traced CT scans of 106 knees with no patellofemoral pathology from 59 subjects from the database system and converted all 2-D images into 3-D models to determine the values for each parameter. We compared the intra- and interobserver reliability of each method using intraclass correlation (ICC) and Bland-Altman method. Results: The values of TT-TG measured by 2-D and 3-D methods were 16.1 ± 4.6 mm and 16.2 ± 4.2 mm, respectively. The ICC values of both methods were comparable (95% limits of agreement between the same observer: - 3.3 to 3.8 mm versus - 2.4 to 2.7 mm and different observers: - 4.3 to 4.9 mm versus - 3.9 to 2.7 mm), with 3-D method results in narrower limits of agreement. Conclusion: TT-TG measurement is reliable using the 2-D method without using advanced radiographic software. The 3-D method of measuring TT-TG provides measurement with narrower variation when compared with the 2-D method. However, both TT-TG distances' measurement methods in the current study were comparable as the variations are not significant.

Biomechanical comparison of new Achilles tendon rupture repair technique the "Giftbox" versus the Krackow technique in New Zealand white rabbits: An experimental animal study.

INTRODUCTION: To compare the strength between the Achilles tendons repaired with the "Giftbox" and the Krackow techniques in New Zealand white rabbits post six weeks of tendon healing. MATERIALS AND METHODS: Eight rabbits were randomized into Giftbox and Krackow groups. Tenotomy was performed on the Achilles tendon of one side of the lower limb and repaired with the respective techniques. The contralateral limb served as control. Subjects were euthanized six weeks post-operative, and both repaired and control Achilles tendons were harvested for biomechanical tensile test. RESULTS: The means of maximum load to rupture and tenacity in the Giftbox group (156.89 ± 38.49 N and 159.98 ± 39.25 gf/tex) were significantly different than Krackow's (103.55 ± 27.48 N and 104.91 ± 26.96 gf/tex, both p = 0.043). CONCLUSION: The tendons repaired with Giftbox technique were biomechanically stronger than those repaired with Krackow technique after six weeks of tendon healing.

A Biomechanical and Ease of Learning Comparison Study of Arthroscopic Sliding Knots.

INTRODUCTION: This study aims to compare the biomechanical properties and ease of learning and tying of our novel knot (UM Knot) with other commonly used arthroscopic sliding knots. MATERIALS AND METHODS: The Duncan, HU, SMC, Pretzel, Nicky's and square knots were selected for comparisons with UM knot. All knots were prepared with size 2 HiFi® suture by a single experienced surgeon and tested with cyclic loading and load to failure tests. The ease of learning was assessed objectively by recording the time to learn the first correct knot and the total number of knots completed in 5 min by surgeons and trainees. RESULTS: The UM knot average failure load is significantly superior to the HU knot (p < 0.05) and comparable to Duncan, SMC, Pretzel and Nicky's knots. According to the ease of learning assessment, UM, Duncan, SMC, Pretzel and Nicky's knots took statistically less time to learn than the HU knot. Although not significant, the failure count due to slippage is fewer in UM knot compared with other knots. CONCLUSIONS: This study showed that UM knot is among the easiest knot to learn and tie, along with Duncan, SMC, Pretzel and Nicky's knots. Their biomechanical properties are comparable and their loads to failure were superior to the HU knot.

Interrater and Intrarater Reliability of the Active Knee Extension (AKE) Test among Healthy Adults.

[Purpose] The purpose of this study was to determine the reliability of the active knee extension (AKE) test among healthy adults. [Subjects] Fourteen healthy participants (10 men and 4 women) volunteered and gave informed consent. [Methods] Two raters conducted AKE tests independently with the aid of a simple and inexpensive stabilizing apparatus. Each knee was measured twice, and the AKE test was repeated one week later. [Results] The interrater reliability intraclass correlation coefficients (ICC2,1) were 0.87 for the dominant knee and 0.81 for the nondominant knee. In addition, the intrarater (test-retest) reliability ICC3,1 values range between 0.78-0.97 and 0.75-0.84 for raters 1 and 2 respectively. The percentages of agreement within 10° for AKE measurements were 93% for the dominant knee and 79% for the nondominant knee. [Conclusion] The finding suggests the current AKE test showed excellent interrater and intrarater reliability for assessing hamstring flexibility in healthy adults.