Effects of initial graft tension on knee stability after anterior cruciate ligament reconstruction using hamstring tendons: a cadaver study

Boylan, Douglas; Greis, Patrick E.; West, John R.; Bachus, Kent N.; Burks, Robert T.

doi:10.1016/s0749-8063(03)00400-6

Cited by 63 publications

(52 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The expected difference of 20N seemed reasonable, considering that a difference in initial graft tension of approximately 25N is required to produce a 2mm difference in AP laxity. 15 This would correspond to a difference in compression force greater than 24N when the knee is in full extension. 16…”

Section: Discussionmentioning

confidence: 99%

Tibiofemoral Compression Force Differences Using Laxity- and Force-Based Initial Graft Tensioning Techniques in the Anterior Cruciate Ligament–Reconstructed Cadaveric Knee

Fleming

Brady

Bradley

et al. 2008

Arthroscopy: The Journal of Arthroscopic & Related Surgery

View full text Add to dashboard Cite

Purpose-To document the tibiofemoral (TF) compression forces produced during clinical initial graft tension protocols.Methods-An image analysis system was used to track the position of the tibia relative to the femur in 11 cadaver knees. TF compression forces were quantified using thin-film pressure sensors. Prior to performing ACL reconstructions with patellar tendon grafts, measurements of TF compression force were obtained from the ACL-intact knee with knee flexion. ACL reconstructions were then performed using "force-based" and "laxity-based" graft tension approaches. Within each approach, high-and low-tension conditions were compared to the ACL-intact condition over the range of knee flexion angles.Results-The TF compression forces for all initial graft tension conditions were significantly greater than that of the normal knee when the knee was in full extension (0°). The TF compression forces when using the laxity-based approach were greater than those produced with the force-based approach. However the laxity-based approach was necessary to restore normal laxity at the time of surgery.Conclusions-The initial graft tension conditions produce different TF compressive force profiles at the time of surgery. A compromise must be made between restoring knee laxity or TF compressive forces when reconstructing the ACL with patellar tendon graft.Clinical Relevance-The TF compression forces were greater in the ACL-reconstructed knee for all the initial graft tension conditions when compared to the ACL-intact knee, and that clinically relevant initial graft tension conditions produce different TF compressive forces.

show abstract

Section: Discussionmentioning

confidence: 99%

Tibiofemoral Compression Force Differences Using Laxity- and Force-Based Initial Graft Tensioning Techniques in the Anterior Cruciate Ligament–Reconstructed Cadaveric Knee

Fleming

Brady

Bradley

et al. 2008

Arthroscopy: The Journal of Arthroscopic & Related Surgery

View full text Add to dashboard Cite

show abstract

“…In contrast, Austin, Phornphutkul, and Wojtys (2007) found that 89N of tension applied at full knee extension was most effective at restoring knee ROM and Gertel, Lew, Lewis, Stewart, and Hunter (1993) found that 67N applied at full extension effectively restored knee stability when using the BPTB graft. In studies investigating the STG grafts, Mae et al (2008a) found a tension of 44N applied at 20 degrees restored TF compressive forces and ROM, compared to Boylan et al (2003) who concluded that 68N applied at 30 degrees knee flexion best restored knee stability.…”

Section: Figure 2-12: Tensioning With a Tensioning Devicementioning

confidence: 97%

“…It has been hypothesised that insufficient tension results in an under-constrained knee, leading to instability, poor graft healing and, ultimately, a poorer outcome (Boylan, Greis, West, Bachus, & Burks, 2003;Kim, Kurosawa, Sakuraba, Ikeda, & Takazawa, 2006). Excessive tension on the other hand is thought to over-constrain the knee, resulting in impaired range of motion (ROM), increased joint compression and a greater risk of graft failure (Boylan et al, 2003;Kim et al, 2006). Thus, optimal graft tension is an important factor in the restoration of stability, biomechanics and function; and a critical factor for superior outcomes (Thompson, Hull, & Howell, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…The application of tension to the graft prior to tibial fixation aims to replicate the femur-graft-tibia complex of the native ACL (Boylan et al, 2003;Heis & Paulos, 2002;Sherman et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…However, what constitutes optimal graft tension has received little attention Kirwan et al, 2013). Anecdotally, too little tension is thought to result in less than ideal joint stability while too much tension is considered to place excessive stress on the graft and other joint structures (Boylan et al, 2003;Sherman et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Graft tensioning in anterior cruciate ligament reconstruction

Kirwan¹

View full text Add to dashboard Cite

BackgroundAnterior cruciate ligament reconstruction (ACLR) is an effective procedure for restoring stability and function. Being a technically demanding procedure, patient outcomes are highly dependent on numerous surgical factors, which are critical for success. The application of tension to the graft prior to tibial fixation is one such factor and is considered essential for the restoration of joint stability, normal knee biomechanics, graft revascularisation and patient function. In applying tension, a key factor is the amount of force applied to the graft. However, the method of applying the tension, position of the knee during tensioning, properties of the graft material, tunnel placement and graft fixation device can all influence the effect that graft tension has on outcomes. Despite the reported importance of graft tension there has been limited empirical evidence defining the best tensioning practice for restoring patient outcome post ACLR. AimsThe goal of this program of research was to explore the effect that different aspects of graft tensioning has on patient function post ACLR. To address the aims of the thesis, three studies were conducted. The first study was a systematic review aimed at examining if a particular amount of tension results in better functional outcomes post ACLR. The second study aimed to compare the effect of two methods of applying graft tension on patient function post ACLR. The study used a prospective randomised controlled trial to compare manual tensioning with the use of a tensioning device. The third study aimed to define current graft tensioning practices and explore the factors that influence surgical decision making. A national survey of Australian orthopaedic surgeons was conducted to achieve the aims of the study. ResultsThe systematic review (study one) revealed that a medium graft tension of 79N to 90N produced the least side-to-side difference (STSD) in anterior posterior (AP) tibial translation as measured by a KT-1000 when compared to tensions <79 or >90N. However, the heterogeneous use of functional outcomes inhibited the ability to draw conclusions on other patient specific functional outcomes.Furthermore, the review highlighted the lack of high quality studies, which also failed to discuss other aspects of graft tension such as the method of applying tension.iii Building on the findings of study one, the second study undertook a RCT to compare the functional outcomes of applying 80N of force with a tensioning device (TD) (n=10) to a manual tensioning method (MT) (n=13) using an estimated force described as a sustained maximum one handed pull.Patients were assessed at pre-surgery and two weeks, three months, six months and 12 months post Based on the findings of study one, tensioning between 79N and 90N appeared to improve the restoration of joint stability, when compared to higher and lower tensions. However, no effect on patient function within 24 months post surgery was apparent. Furthermore, study two observed that tension did not appear to have an...

show abstract

In vitro comparison of tension and stiffness between hamstring tendon and patella tendon grafts

Elias¹,

Surya²,

Ciccone³

2008

Journal Orthopaedic Research

View full text Add to dashboard Cite

Following anterior cruciate ligament reconstruction, grafts relax and warm from the temperature of the operating room to body temperature. The current study compared graft tension and stiffness between patella tendon and hamstring tendon grafts. Six quadruple strand hamstring tendon grafts and six patella tendon grafts were preconditioned and loaded to 105 N while at 208C. Graft tension and stiffness were measured after 15 min, after an additional 4 h, and after increasing the temperature to 348C. A two-way repeated-measures analysis of variance and a post hoc test were used to compare the measurements between the two types of graft and identify significant ( p < 0.05) changes for each type of graft. Tension was significantly larger for the patella tendon grafts, although the stiffness values were not significantly different ( p > 0.8). For both types of graft, tension and stiffness decreased significantly with time and the temperature increase. The lowest tension and stiffness measurements were 50 AE 11 N and 129 AE 35 N/mm, respectively, for the patella tendon grafts, compared to 18 AE 5 N and 115 AE 11 N/mm, respectively, for the hamstring tendon grafts. Both types of graft lose tension to relaxation and a temperature increase, but the tension loss is larger for hamstring tendon grafts. Initial tension is applied to autografts used for anterior cruciate ligament reconstruction to limit postoperative knee laxity. Recommended initial tension levels range from 20 to 90 N for patella tendon grafts [1][2][3][4][5] and from 70 to 80 N 1,6,7 for hamstring tendon grafts. Following reconstruction, viscoelastic relaxation decreases the tension within a graft. Hamstring tendon grafts are typically preconditioned on a graft board at approximately 89 N 8-11 to minimize the tension loss. Two in vitro studies that mimicked preconditioning and application of initial tension determined that the tension within hamstring tendon grafts decreases by more than 50% within an hour.10,12 Patella tendon grafts are not typically preconditioned outside the knee prior to reconstruction, presumably due to the belief that patella tendon grafts are less susceptible to relaxation. A 50% decrease in tension over 15 min has been measured for patella tendon grafts that were not preconditioned immediately prior to application of tension.13 As the graft tension decreases, the stiffness needed to maintain knee stability increases.14 The stiffness of hamstring tendon grafts has been shown to decrease as the tension decreases. 12 The relationship between stiffness and tension has not been determined for patella tendon grafts.Graft tension and stiffness can also decrease due to an increase in temperature. Autografts typically cool to the temperature of the operating room prior to implantation in the knee and warm to body temperature postoperatively. Following complete relaxation, an increase in temperature from operating room to body temperature has been shown to decrease the tension and stiffness of hamstring tendon grafts by approximately...

show abstract

Effects of initial graft tension on knee stability after anterior cruciate ligament reconstruction using hamstring tendons: a cadaver study

Cited by 63 publications

References 17 publications

Tibiofemoral Compression Force Differences Using Laxity- and Force-Based Initial Graft Tensioning Techniques in the Anterior Cruciate Ligament–Reconstructed Cadaveric Knee

Tibiofemoral Compression Force Differences Using Laxity- and Force-Based Initial Graft Tensioning Techniques in the Anterior Cruciate Ligament–Reconstructed Cadaveric Knee

Graft tensioning in anterior cruciate ligament reconstruction

In vitro comparison of tension and stiffness between hamstring tendon and patella tendon grafts

Contact Info

Product

Resources

About