Biomechanical effects of stitches on the intra-articular mid-substance of quadruple hamstring-tendon grafts for anterior cruciate ligament reconstruction – a pilot comparative cadaveric study

Saur Maurise,Clavert Philippe,Bonnomet François,Favreau Henri,Ehlinger Matthieu 대한슬관절학회 2020 대한슬관절학회지 Vol.32 No.-

Background: There is little data in the literature regarding the preparation methods of the intra-articular portion of quadruple hamstring-tendon grafts for anterior cruciate ligament (ACL) reconstruction. The aim of this study was to compare the biomechanical properties of a sutured transplant to that of a non-sutured transplant. The hypothesis was that adding stitches to the intra-articular portion of the graft increased its resistance. Method: A comparative cadaveric study was carried out on five pairs of knees. The average age of the cadavers was 68 years. The exclusion criterion was past knee surgery. In the Sutured Group (SG) two stitches were made on the grafts. No stitches were made on the grafts of the Non-sutured Group (NSG). A tensile failure test was carried out using an Instron® loading machine. The maximal load to failure and stiffness were recorded and we observed the mode of failure for each graft. Statistical analysis was performed using the Wilcoxon rank sum test. Level of significance was set at p < 0.05. Results: The hypothesis proposed was not confirmed; adding stitches to the intra-articular portion of the fourstrand hamstring-tendon graft does not increase its biomechanical properties. The maximal load to failure was 233.5 N ± 40.6 (186.7–274.5 N) for the NSG, 19.6% higher than for the SG which was 195.2 N ± 42.9 (139.0–238.2 N). Nevertheless, the difference observed was not statistically significant (p = 0.188). The stiffness of the grafts for the NSG was 23.5 N/mm ± 5.3 (17.8–29 N/mm) and 19.7 N/mm ± 5.5 (13.2–24.7 N/mm) for the SG grafts. Overall stiffness values for the NSG were 19% higher than those of the SG; however, the results were not statistically significant (p = 0.438). The failure mode was a rupture at the fixation point except for one sample from the SG which failed at an intra-articular stitch. Conclusion: Whilst the initial hypothesis was not verified, nevertheless, the maximal loads to failure and stiffness were approximately 20% higher when there were no intra-articular stitches compared to the situation where stitches were added to the intra-articular portion of the graft. This was a cadaveric pilot study and, therefore, whilst we are not able to extend our results to clinical practice, the outcomes would indicate the need for further development of this and related protocols deriving from the question of whether there is weakening the graft when adding stitches to its midsubstance. These results remain to be confirmed by further research.

요추부 척추관 협착증 치료를 위한 요추부 극돌기 삽입술의 추간판 내 압력 분포 변화에 관한 생체역학적 분석

권순영(Soon-Yong Kwon),전성철(Sung-Chul Jun),문수정(Soo-Jung Moon),탁계래(Gye-Rae Tack),이성재(Sung-Jae Lee),신규철(Kyu-Cheol Shin) 대한정형외과학회 2007 대한정형외과학회지 Vol.42 No.6

목적: 요추부 척추관 협착증 치료를 위한 여러 형태의 요추부 극돌기 spacer 중 가장 초기 형태인 골시멘트 spacer 삽입에 따른 추간판의 생체역학적 압력 변화를 분석하고자 하였다. 대상 및 방법: 시편으로는 생후 2주일 미만의 송아지 요추 다분절 (Ll-L5) 6개를 이용하였다. 각각 3개의 시편을 정상군과 요추 3-4번 극돌기 사이에 골시멘트 12 mm 원형 spacer를 삽입한 시술군으로 구분하였다. 압축 하중 (700 N) 및 신전 하중 (700 N+7.5 Nm) 하에서 압력센서를 이용하여 정상군과 시술군의 요추 2-3번, 3-4번, 4-5번 사이의 전방 섬유륜, 수핵, 후방 섬유륜, 후측방 섬유륜에서의 압력을 측정하였다. 결과: 정상 시편의 경우 압축 하중에 비해 신전 하중 시 후방 부위 섬유륜내의 압력이 증가하는 양상을 나타내었다. 그리고 spacer를 삽입한 후 압축 하중 및 신전 하중에서 인접한 추간판(L2-L3, L4-L5)의 압력 변화는 정상군과의 비교 시 통계학적으로 유의한 차이를 보이지 않았다(p>0.05). 하지만 신전 하중 하에서, 정상군의 요추 3-4번 사이의 수핵, 정 후방 섬유륜, 후 측방 섬유륜에서의 압력이 l.48±0.27 MPa, l.42±0.21 MPa, 1.71±0.56 MPa로 나타난 것에 비해, 시술 후 압력이 1.11±0.18 MPa, 0.96±0.31 MPa, 1.08±0.14 MPa로, 수핵의 경우 25%, 정 후방 섬유륜에서는 31.7%, 후 측방 섬유륜에서는 36.8%의 감소율을 보였고, 통계학적인 유의한 차이를 나타내었다(p<0.05). 결론: 신전 하중 하에서의 압력의 감소 효과는, 요추부의 신전을 유발하는 자세에 따라 증상이 나타나는 요추부 척추관 협착증의 원인으로 알려진 추간판의 팽륜의 감소를 유발할 것으로 사료된다. 또한 기존 내고정 장치를 이용한 시술 부위의 너무 강한 융합은 인접한 추간판에서의 퇴행화를 가속화 시킨다고 보고 되었다. 또한 시술 후 인접한 추간판내 압력의 경우 정상군의 결과와 유의한 차이가 없었으며, 이는 spacer의 삽입술이 인접한 추간판의 생체 역학적 역할에 변화를 유발하지 않을 것으로 사료된다. Purpose: To assess the biomechanical effects and effectiveness of an interspinous spinal spacer (ISS) on the intradiscal pressure using in vitro biomechanical tests. Materials and Methods: Six calf spine specimens (less than 2 weeks of age, L1-L5) were divided to two groups the intact and the surgery groups (n=3 each). For the surgery group, an ISS made from PMMA (Greek pi=12-mm) were inserted into the space between the spinous processes of L3-L4. The intradiscal pressures at the various regions of the annulus (anterior, posterior, and posterolateral locations) and the nucleus pulposus were measured using the four pressure transducers under pure compression (700 N) and extension loads (700 N+7.5 Nm). Results: An increase in pressure was observed from neutral to extension at the posterior and posterolateral annulus. After inserting the ISS, the changes in pressure at the adjacent disc levels (L2-L3, L4-L5) were negligible regardless of the loading conditions (p>0.05). However, at the implanted level (L3-L4) statistically significant changes in the pressure were found under extension loading at the nucleus pulposus, posterior and posterolateral regions of the annulus with a pressure drop from 1.48 MPa, 1.42 MPa, 1.71 MPa to 1.11 MPa, 0.961 MPa, 1.08 MPa, at the respective locations (p<0.05). The relative percentage decrease were 25%, 31.7%, and 36.8%. Conclusion: On the implanted level, these results showed that the insertion of the ISS with PMMA can effectively reduce the intradiscal pressures by at least 25% quite uniformly over the intraver-tebral disc during extension. More effective reduction was observed at the posterolateral location. The pressure changes at the adjacent levels were negligible in contrast to the abnormal pressure changes that are frequently reported after conventional rigid fusion. This suggests that the likelihood of adjacent level degeneration after surgery can be minimized using the ISS insertion.

Biomechanical and histological behavior of zirconia implants: an experiment in the rat

Kohal, Ralf J.,Wolkewitz, Martin,Hinze, Marc,Han, Jung-Suk,Bä,chle, Maria,Butz, Frank Blackwell Publishing Ltd 2009 Clinical oral implants research Vol.20 No.4

<P>Abstract</P><P>Objective</P><P>This study aimed at evaluating the integration of zirconia implants in a rat femur model.</P><P>Material and methods</P><P>Zirconia implants with two distinct surface topographies were compared with titanium implants with similar topographies. Titanium and zirconia implants were placed into the femurs of 42 male Sprague–Dawley rats. Four groups of implants were utilized: machined zirconia implants, zirconia implants with a rough surface, machined titanium implants, and titanium implants with an electrochemically roughened surface. After a healing period of 28 days, the load-bearing capacity between the bone and the implant surface was evaluated by a push-in test. Additionally, after a healing period of 14 and 28 days, respectively, bone tissue specimens containing the implants were processed and histologically analyzed.</P><P>Results</P><P>The mean mineralized bone-to-implant contact showed the highest values after 14 and 28 days for the rough surfaces (titanium: 36%/45%; zirconia: 45%/59%). Also, the push-in test showed higher values for the textured implant surfaces, with no statistical significance between titanium (34 N) and zirconia (45.8 N).</P><P>Conclusions</P><P>Within the limits of the animal investigation presented, it was concluded that all tested zirconia and titanium implant surfaces were biocompatible and osseoconductive. The presented surface modification of zirconia implants showed no difference regarding the histological and biomechanical results compared with an established electrochemically modified titanium implant surface.</P>

인두조직의 점 탄성특성의 수학적모델링에 관한 연구

김성민,김남현 대한의용생체공학회 1998 의공학회지 Vol.19 No.5

A mathematical model of viscoelasticity on the material property of human pharyngeal tissue utilizing Y.C. Fung's Quasi-linear viscoelastic theory is proposed based on cyclic load, stress relaxation, incremental load, and uniaxial tensile load tests. The material properties are characterized and compared with other biological materials' results. The mathematical model is proposed by combining two characteristic functions determined from the stress relaxation and uniaxial tensile load tests. The reduced stress relaxation function G(t) and elastic response function S(t) are obtained from stress relaxation test and uniaxial tensile load test results respectively. Then the model describing stress-time history of the tissue is implemented utilizing two functions. The proposed model is evaluated and validated by comparing the model's cyclic behaviour with experimental results. The model data could be utilized as an important information for constructing 3-dimensional biomechanical model of human pharynx using FEM(Finite Element Method). Y.C. Fung[1]에 의한 연조직의 점탄성에 관한 수학적 모델이론 (Fung's Quasi-linear vlscoelastic theory)을 이용하여 인간의 인두조직의 점탄성(vlscoelatlcity)특성을 측정하기 위하여 반복성하중(cyclic load) ,응력완화 (tensile stress relaxation), incremental load, 그리고 일축성인장 (uniaxial tensile) 시험 등을 실시하였다. 실험적으로 측정한 인두조직의 점탄성특성이 이미 조사된 다른 조직의 점탄성특성과 정량적으로 비교되었다. 인두조직의 점탄성특성의 정량화를 위하여 Y.C.Fung의 수학적 모델이 적용되었는데 응력완화(tensile stress relaxation) 시험 측정결과로부터 도출된 표준화된 응력완화(reduced stress relaxation)함수 G(t)와 일축성인장(uniaxial tensile)시험에서 도출된 탄성반응(elastic response)함수 5(t)를 이용하여 시간에 따른 응력의 궤적을 산출하여 이를 반복성 하중(cyclic load)실험에서 측정된 결과와 비교, 분석하였다. 이러한 인두조직의 점탄성특성에 관한 연구결과는 향후 유한요소를 이용한 인두의 생체역학적 모델의 기본 데이터로 이용될 수 있다.

모의 충돌 시험을 통한 자동차용 유아 시트의 설계

박수진(Sujin Park),박동운(Dongwoon Park),문경섭(Gyeongsub Moon),유완석(Wansuk Yoo),김경식(Kyeongsik Kim) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

As one of Child Restraint System(CRS), child seats are widely used. In this paper, the dynamic simulation of child seat was carried out with the LS-DYNA software, and the results from dynamic simulation were compared to the sled test. The comparison between the simulation and sled test showed a good agreement, and the results are applied for the improved design of 6-point belt type CRS. The 6-point belt type CRS is divided into several subregions and optimized. The design procedures to develop new child seats are arranged.

하악골 신장술에서 압축자극을 통한 골 재생방식에 대한 생체 역학적 평가

허준(June Heo),김욱규(Uk-Kyu Kim),황대석(Dae-Seok Hwang),김용덕(Yong-Deok Kim),신상훈(Sang-Hun Shin),정인교(In-Kyo Chung),김철훈(Cheol-Hun Kim),윤석영(Seok-Young Yun) 대한구강악안면외과학회 2007 대한구강악안면외과학회지 Vol.33 No.5

The purpose of this study was to investigate the clinical, biomechanical, and histologic changes in new distraction osteogenesis (DO) technique combined with a compression stimulation in accordance to different compression-distraction force ratio. 23 adult male rabbits underwent open-osteotomy at the mandibular body area and a external distraction device was applied. In the control group of 8 rabbits, only a 8 mm of distraction was performed by conventional DO technique. In an experimental group of 15 rabbits, a distraction followed by a compression force was performed according to the ratio of compression-distraction suggested by authors. The rate of experimental group I was set up as a 2 mm compression versus 10 mm distraction and the rate of experimental group II was set up as a 3 mm compression versus 11 mm distraction. All the rabbits were sacrificed for a gross finding, biomechanical, histomorphometric and histologic findings at the time of 55 days from the operation day. The results were as follows: 1. On the gross findings, because all rabbits had a sufficient healing time, every distracted new bone had good bone quality and we could not find any difference among all three groups. 2. In the histologic findings, rapid bone maturation (wide lamellar bone formation in the cancellous and cortical bone areas) was observed in two experimental groups compared to the control group. 3. On the bone density tests, the experimental group II showed higher bone density than the other experimental group and control group (control group - 0,2906 g/cm2, experimental group I - 0.2961 g/cm2, experimental group II - 0.3328 g/cm2). 4. On the biomechanical tests, the experimental group II had significantly higher bone microhardness than the other experimental group and control group (control group - 252.7 MPa, experimental group I - 263.5 MPa, experimental group II - 426.0 MPa). 5. On the microhardness tests, when we compared the hardness ratio of distracted bone versus normal bone, we could find experimental group II had significantly higher hardness ratio than the other experimental group and control group (control group - 0.47, experimental group I - 0.575, experimental group II - 0.80). From this study, we could deduce that the modified distraction osteogenesis method with a compression stimulation might improve the quality of bone regeneration and shorten the consolidation period in comparison with conventional distraction osteogenesis techniques

Biomechanical Test for Repair Technique of Full-thickness Rotator Cuff Tear

Chae-Ouk Lim,Kyoung-Jin Park 대한견주관절의학회 2016 대한견주관절학회지 Vol.19 No.1

The arthroscopic rotator cuff repair is now considered a mainstream technique with highly satisfactory clinical results. However, concerns remain regarding healing failures for large and massive tears and high revision rate. In recent decades, various repair strategies and construct configurations have been developed for rotator cuff repair with the understanding that many factors contribute to the structural integrity of the repaired construct. The focus of biomechanical test in arthroscopic repair has been on increasing fixation strength and restoration of the footprint contact characteristics to provide early rehabilitation and improve healing. These include repaired rotator cuff tendon-footprint motion, increased tendon-footprint contact area and pressure, and tissue quality of tendon and bone. Recent studies have shown that a transosseous tunnel technique provides improved contact area and pressure between rotator cuff tendon and insertion footprint, and the technique of using double rows of suture anchors to recreate the native footprint attachment has been recently described. The transosseous equivalent suture bridge technique has the highest contact pressure and fixation force. In this review, the biomechanical tests about repair techniques of rotator cuff tear will be reviewed and discussed.

Recommendations for Biomechanical Testing of Hip Protectors

Seunghoon Lee,Seikwon Park,Daehan Jung,Eunjin Jeon,Hee-Eun Kim,Sungho Kim,Wonsup Lee,Heecheon You 대한인간공학회 2014 대한인간공학회 학술대회논문집 Vol.2014 No.11

Objective: The objective of this study is to summarize and collate the techniques for measuring and optimizing the biomechanical performance of hip protectors for constructing experimental design in systematic reviews. Background: Hip fracture in older people usually results from a fall on the hip. Hip protectors have been advocated as a means to reduce the risk of hip fracture. However, there is a lack of standards test method for such laboratory tests, and there are conflicting reports on the force attenuation provided by specific devices from researchers using fundamentally different test systems Method: The literature was searched on Science direct databases with keywords (e.g., hip protector, fracture, testing) in the searching areas of titles, keywords, abstracts and full texts. We selected 24 relevant literatures through 5-step (S1: keyword search, S2: title screening, S3: abstract screening, S4: full paper screening, S5: relevance evaluation). Results: The performance of hip protectors can be represented as peak force at the femoral neck and percent reduction in peak force provided by a given hip protector, when compared with unpadded conditions. To provide reasonable results, the test system should accurately simulate pelvic anatomy and the impact velocity (3.4 m/s), pelvic stiffness (39-55 kN/m), and impact mass (22-33 kg) during impact. Conclusion & Application: This study can be used in measuring and optimizing the biomechanical performance of hip protectors. Also, it can contribute to building a standard test method for hip protector.

Novel approach to assessing the primary stability of dental implants under functional cyclic loading in vitro: a biomechanical pilot study using synthetic bone

Jean-Pierre Fischer,Stefan Schleifenbaum,Felicitas Gelberg,Thomas Barth,Toni Wendler,Sabine Löffler 대한치주과학회 2024 Journal of Periodontal & Implant Science Vol.54 No.3

Purpose: This pilot study was conducted to develop a novel test setup for the in vitro assessment of the primary stability of dental implants. This was achieved by characterising their long-term behaviour based on the continuous recording of micromotions resulting from dynamic and cyclic loading. Methods: Twenty screw implants, each 11 mm in length and either 3.8 mm (for premolars) or 4.3 mm (for molars) in diameter, were inserted into the posterior region of 5 synthetic mandibular models. Physiological masticatory loads were simulated by superimposing cyclic buccal-lingual movement of the mandible with a vertically applied masticatory force. Using an optical 3-dimensional (3D) measuring system, the micromotions of the dental crowns relative to the alveolar bone resulting from alternating off-centre loads were concurrently determined over 10,000 test cycles. Results: The buccal-lingual deflections of the dental crowns significantly increased from cycle 10 to cycle 10,000 (P<0.05). The deflections increased sharply during the first 500 cycles before approaching a plateau. Premolars exhibited greater maximum deflections than molars. The bone regions located mesially and distally adjacent to the loaded implants demonstrated deflections that occurred synchronously and in the same direction as the applied loads. The overall spatial movement of the implants over time followed an hourglassshaped loosening pattern with a characteristic pivot point 5.5±1.1 mm from the apical end. Conclusions: In synthetic mandibular models, the cyclic reciprocal loading of dental implants with an average masticatory force produces significant loosening. The evasive movements observed in the alveolar bone suggest that its anatomy and yielding could significantly influence the force distribution and, consequently, the mechanical behaviour of dental implants. The 3D visualisation of the overall implant movement under functional cyclic loading complements known methods and can contribute to the development of implant designs and surgical techniques by providing a more profound understanding of dynamic bone-implant interactions.

Biomechanical Comparison of Soft Tissue Reconstructions in the Treatment of Medial Patellar Luxation in Dogs

김상연,문희섭,박성곤,홍성진,최희복,황태성,Yong-Hyun Hwang,이재훈,이희천 한국임상수의학회 2017 한국임상수의학회지 Vol.34 No.6

The present study aimed to document the biomechanical findings of soft tissue reconstruction surgeries for the treatment of medial patellar luxation in dogs. Stifle joints (n = 12) from dogs weighing 4.1-8.4 kg were used in this study. The following soft tissue reconstruction techniques used for the treatment of medial patellar luxation were selected for this study: vastus medialis release, medial retinacular release, and capsule release for medial realignment (n = 6), and retinacular imbrication and anti-rotational suture for lateral realignment (n = 6). A 5-kg traction using an electronic scale was applied at 45o laterally for medial realignment and medially for lateral realignment. Fluoroscopic imaging was used to measure the length of patellar displacement (LPD) in each technique. Among medial realignment techniques, capsule release had the highest horizontal LPD; vastus medialis release had significantly higher horizontal LPD than medial retinacular release. Vastus medialis release had the smallest increase statistically in vertical LPD, and vertical LPD did not differ significantly between medial retinacular and capsule release. Among lateral realignment techniques, the horizontal LPD was significantly higher in anti-rotational suture with retinacular imbrication than in retinacular imbrication alone, but the vertical LPD did not differ significantly between the two groups. Our findings indicated that vastus medialis release could decrease the medial tension on the patella without inducing patellar instability in dogs. Both medial retinacular and capsule release could increase patellar instability; moreover, medial retinacular release does not decrease the medial tension on the patella. Antirotational suture with retinacular imbrication provides more lateral tension than retinacular imbrication alone.