• Clinics in Shoulder and Elbow
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• 제21권4호
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• pp.246-251
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• 2018

Compared to single row repair, use of lateral row anchors in suture bridge rotator cuff repair enhances repair strength and increases footprint contact area. If a lateral knotless anchor (push-in design) is inserted into osteoporotic bone, pull-out of the lateral row anchor can developed. However, failures of lateral row anchors have been reported at several months after surgery. In our cases, even though complete cuff healing occurred, delayed pull-out of the lateral row anchor in the suture bridge repair occurred. In comparison to a conventional medial anchor, further biomechanical evaluation of the pull-out force, design, and insertion angle of the lateral anchor is needed in future studies. We report three cases with delayed pull-out of lateral row anchor in suture bridge rotator cuff repair with a literature review.

• Clinics in Shoulder and Elbow
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• 제25권1호
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• pp.15-21
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• 2022

Background: This study was performed to identify the incidence of screw in-type lateral anchor pull-out in patients older than 60 years who underwent rotator cuff repair for large to massive rotator cuff tear (RCT). Methods: We reviewed 25 patients over 60 who were diagnosed with large to massive RCT and underwent arthroscopic rotator cuff repair in our hospital from March 2017 to February 2021. Preoperative tear size (anterior to posterior, medial to lateral) was measured via preoperative magnetic resonance imaging (MRI). All 25 patients underwent MRI scanning on postoperative day 1 and at 3 months after surgery. The change of anchor position was measured in axial views on MRI images postoperative day 1 and 3 months after surgery. And it was statistically compared according to bone mineral density (BMD), sex, and number of lateral anchors. Results: Two MRIs (postoperative day 1 and 3 months) in 25 patients were compared. Anchor pull-out occurred in six patients during 3 months (6.7%), and the mean pull-out length difference was 1.56 mm (range, 0.16-2.58 mm). There was no significant difference in the number of pull-out anchors, degree of pull-out difference by comparing BMD (A, BMD≤-2.5; B, BMD>-2.5), sex, or number of anchors used in each surgery (C, two anchors; D, three anchors) (p>0.05). Conclusions: Pull-out of screw in-type anchors was rarely observed and the mean pull-out length difference was negligibly small in our study. The screw in-type lateral anchor seems to be a decent option without concern of anchor pull-out even in elderly patients.

• 한국지반공학회논문집
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• 제33권11호
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• pp.35-43
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• 2017

본 연구에서는 정착부 표면에 저항체를 설치한 앵커의 인발거동특성을 모형시험을 통해 규명하였다. 모형시험은 원형의 토조 중앙에 앵커체를 설치한 후 앵커를 등속으로 인발하면서 인발저항력을 측정하였다. 본 연구에서는 앵커형식(저항체 설치 유무), 앵커체 표면의 마찰조건($1/3{\phi}$, $2/3{\phi}$, ${\phi}$)과 돌기형 저항체 개수(1set, 2set, 4set), 돌기형 저항체 높이(0.05d, 0.10d, 0.20d) 등 총 10가지의 조건에 대하여 인발시험을 실시하였다. 인발시에는 일정한 속도(1mm/min)를 유지하였으며, 최대 80mm까지 인발하여 각 조건별 인발하중 및 변위를 측정하였다. 인발시험 결과 확장형 앵커는 마찰형 앵커와 비교하여 최대 인발저항력 뿐만 아니라 잔류 인발저항력도 크게 발생하는 것으로 분석되었다. 돌기형 저항체의 설치개수 증가에 따라 최대 인발저항력이 증가하였으며, 잔류 저항력 비율은 171~591%로 마찰형 앵커에 비해 현저하게 증가하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.788-795
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• 2005

In this study, the progressive failure and creep of the traditional ground anchor structure were decreased and a new ground anchor that can attain the required pull-out resistance even in soft sandy soils with low confining pressure was developed. Ground anchors are classified depending on the kind of stress the grout is subjected. If the grout material is subjected to tension then it is classified as tension anchor while when the grout material is subjected to compression it is classified as compression anchor. The ground anchor that possesses both the tension and compression mechanism mentioned above is known as composition anchor. It is the objective of this study to develope this type of composition anchor. The structure of the newly developed ground anchor was presented. Pull-out test in different types of soil and the behaviour during Pull-out test was also presented.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.387-394
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• 2000

In the present study, laboratory pull-out tests with screw anchors are carried out to investigate behavior characteristics of underground structures applied uplift seepage forces. Small scaled pull-out tests in sand were conducted under saturated condition. And then, it was observed that the upward displacement as well as the pullout load varied with spacing of the anchor. Also, analyses have been performed with the aim of pointing out the effects of various parameters on the group effect of the screw anchors.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.545-552
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• 2008

To insure the quality and safety of ground anchors, pull-out test of anchor has to be done. In the individually controlled pull-out test system, pull-out device is used to introduce the same pull-out force to individual tendon that has a different length and a deflection. That is, that device has a separate pull-out oil jack to each tendon, thus the pull-out length of each jack is not the same, but that device introduces each tendon to the same pull-out force. In this study, the in-situ pull-out tests for the compression anchors were performed and its test results were analysed and compared to the results of center hole pull-out tests. In the case of pulling out each tendon using the individually controlled pull-out test device, the pull-out forces were distributed to a individual tendon. That device is excellent one that can solve the cause of unequal pull-out forces of each tendon appearing in the manufacture process and construction of anchors, and unequal pull-out forces due to the deferent length.

• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2009년도 제17차 학술대회
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• pp.159-159
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• 2009

Repeated pulling-out of a suture anchor in the lateral row despite repeated attempts at insertion during a rotator cuff repair is not uncommon with the suture-bridge technique, especially in patients with osteoporosis. We describe a simple procedure for dealing with the pull-out of a PushLock anchor in the lateral row using a suture anchor with a suture eyelet during rotator cuff repair applying the suture-bridge technique.

• 대한의용생체공학회:의공학회지
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• 제29권2호
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• pp.132-138
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• 2008

We investigated the biomechanical properties of a newly designed self-expansion type anterior cruciate ligament (ACL) anchor. The ACL anchor consists of the ring section giving the elastic force, the wedge for maintaining in contact with the femur tunnel wall and the link suspending hamstring graft or artificial ligament. The main design parameters that determine the performance of this device were the expansion angle (${\theta}$) and the thickness ($t_R$). The Ti6Al4V anchors were heated after inserting in a jig for 1 hour at $800^{\circ}C$ in a protective argon gas atmosphere and allowed to cool to room temperature in the furnace. In order to investigate the influence of the expansion angle and the thickness of the ring on the biomechanical properties of the anchor, the maximum pull-out load, stiffness and slippage of the ACL anchor were measured using the pull-out tester, and statistical analyses were also executed. The present results showed that the design parameters gave a significant effect on the performance of the self- expansion type of anchor. The pull-out load of the ACL anchors significantly increased as the thickness of the ring section was increased, having a similar trend for both expansion angles. The ACL anchor showed about 2.5 times higher values of the pull-out load than that of the minimum load (500N)required for the "accelerated rehabilitation". The optimum ${\theta}$ and $t_R$ values of this ACL anchor were suggested to have sufficient resistance against the pull-out force, high stiffness and relatively low slippage after ACL reconstruction.

• 대한토목학회논문집
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• 제26권3A호
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• pp.555-563
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• 2006

최근 많은 교량들이 점증하는 교통량에 의해 상부슬래브 폭이 부족해지거나 침식으로 인해 하부구조가 구조적으로 취약해지는 경향이 있다. 이 경우 상부슬래브나 교각을 확장하여 보강하는 것이 경제적이기 때문에 실험 자료와 현장의 시공경험 등을 통해 적절한 교량의 확장방안을 확립할 필요가 있다. 그렇지만, 부착식 앵커를 사용하여 교량의 하부구조를 보수 보강하는 경우 신 구 콘크리트의 일체성 확보와 관련된 기존 실험자료는 매우 부족한 실정이며, 이에 따라 부착식 앵커를 사용하여 구조적인 일체성을 확보하기 위한 실험적인 연구가 매우 시급하다고 할 수 있다. 이와 관련하여 본 논문에서는 부착식 앵커를 사용할 경우의 인발 및 전단 특성을 실험을 통해 밝히고자 하였다. 이를 위해 부착길이, 앵커직경 및 앵커경사를 포함한 다양한 실험변수를 가진 시편을 제작하여 인발 및 전단실험을 수행하였다. 실험결과 부착길이가 길어지고 앵커직경이 커질수록 부착력은 증가하고 부착강도는 감소하였다. 또한, 앵커경사가 커질수록 부착력 및 부착강도가 증가하지만 경사가 $5^{\circ}$ 이상인 경우 경사에 의한 효율이 감소하는 것을 알 수 있었다. 전단실험을 통해서는 앵커직경이 D19 이상을 사용하는 것이 적절할 것으로 판단되었다. 결론적으로, 향후 모델실험을 포함한 관련 자료의 축적이 이루어지는 경우 본 연구에서 수행한 실험 자료와 함께 부착식 앵커를 사용하여 보강된 신 구 콘크리트의 일체성을 확보하는데 많은 기여를 할 수 있을 것으로 기대된다.

• 한국지반공학회논문집
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• 제29권1호
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• pp.121-133
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• 2013

본 논문에서는 사질토에서 스크류 앵커 파일의 인발 저항 특성에 대한 실험적 내용을 다루었다. SAP에 대한 소개 및 적용분야 등의 간략한 설명을 시작으로 스크류 파일의 인발저항특성에 대한 이론적 배경들과 축소모형실험의 수행 방법에 대해 소개하였다. 조밀한 모래조건과 느슨한 모래조건에서 스크류 앵커 파일의 인발저항특성을 분석하기 위해 스크류 사이의 간격인 피치와 스크류의 직경을 변화시켜 실험을 수행하였고, 스크류 앵커 파일의 파괴 메커니즘에 근거한 이론적 인발특성에 관한 기존연구들을 검토하여 비교하였다. 연구결과 조밀한 모래조건과 느슨한 모래조건 모두에서 피치의 변화에 따른 인발저항력의 차이는 매우 미미하였고, 직경의 변화에 따라 인발 저항력이 상대적으로 많이 증가함을 확인할 수 있었다. 본 논문에서는 실험결과를 사질토에서 스크류 앵커 파일의 인발저항특성을 파악할 수 있도록 제시하였으며 기존의 이론식과 비교하여 실무적 관점에서의 검토 내용을 기술하였다.