A biomechanical study on preloaded compression eVect on headless screws.

INTRODUCTION: Commonly used headless design screws such as Acutrak and Herbert screws have limited compressive effect on short fragment fixation. Therefore, we investigated whether preloaded compression techniques could be helpful in improving the compression effect. METHOD: A prototype of interfragmentary compression screw was designed with a constant pitch to avoid self-compressive effect. Preloaded compression was achieved with a sleeve device before the insertion of the trailer side (the leading side was inserted). Prototype screw test results were compared with those of Acutrak and Herbert screws. Eight pullout and eight compression tests were performed for each of the three screws using homogenous synthetic bone blocks. RESULTS: The mean pullout forces of the Acutrak, Herbert and prototype screws were 67.21, 45.90 and 61.88 N, respectively. Preloaded compression (18.15 N) was higher than the compression produced by Acutrak (15.27 N) and Herbert (15.11 N) screws (p < 0.05). However, at the end of full insertion, half of the power obtained by preloaded compression was lost. CONCLUSION: Preloaded compression technique was successful in attaining maximum compression rate. During trailing-side insertion, constant pitch design failed to keep compression rate. Variable pitches can be useful to preserve or increase compression rate. In addition, sleeve usage may be more advantageous in thin fragment fixation.

Flexible flatfoot and related factors in primary school children: a report of a screening study.

The aim of this study was to analyze the longitudinal arch morphology and related factors in primary school children. Five hundred and seventy-nine primary school children were enrolled in the study. Generalized joint laxity, foot progression angle, frontal hindfoot alignment, and longitudinal arch height in dynamic position were evaluated. The footprints were recorded by Harris and Beath footprint mat and arch index of Staheli was calculated. The mean age was 9.23 +/- 1.66 years. Four hundred and fifty-six children (82.8%) were evaluated as normal and mild flexible flatfoot, and 95 children (17.2%) were evaluated as moderate and severe flexible flatfoot. The mean arch indices of the feet was 0.74 +/- 0.25. The percentage of flexible flatfoot in hypermobile and non-hypermobile children was found 27.6 and 13.4%, respectively. There was a statistically significant difference in dynamic arch evaluation between hypermobile and non-hypermobile children. There was a significant negative correlation between arch index and age, and a significant negative correlation between hypermobility score and age. Our study confirms that the flexible flatfoot and the hypermobility are developmental profiles.

[Shoulder instability: classification and methods of clinical examination]. / Omuz instabilitesinin siniflandirilmasi ve klinik muayene yöntemleri.

The shoulder is a complex joint whose stability relies on both dynamic and static factors. Dysfunction of one of these components gives rise to shoulder problems. Diagnosis of shoulder instability depends on a detailed history and appropriate physical examination. Despite the presence of many tests, none has proved to be purely diagnostic for shoulder instability. Therefore, these tests should be regarded as a part of the diagnostic procedure rather than a referral to diagnosis itself. Tests performed to assess laxity and instability are different in nature; thus, positive laxity tests do not necessarily show instability unless supported by further evidence. The reliability of the tests for superior labrum anterior-posterior lesions has not been adequately validated by clinical studies and few anatomical studies have examined the effect of these tests on the superior labral complex.