Evaluation of active knee flexion and hamstring strength after anterior cruciate ligament reconstruction using hamstring tendons

Purpose: The purpose of this study was to evaluate active knee flexion range of motion and hamstring strength following hamstring anterior cruciate ligament (ACL) reconstruction. Type of Study: Case control study, consecutive sample. Methods: Seventy-four consecutive patients who had undergone hamstring ACL reconstruction underwent isokinetic muscle strength testing at 2 years post surgery. Measurements of the maximum standing active knee flexion angle with the hip extended were also taken. During isokinetic testing, we evaluated flexion torque at 90° of knee flexion, in addition to the peak flexion torque. We further compared these parameters of muscle strength around the knee for the patients in whom only semitendinosus tendon was harvested as a graft source (ST group), and those from whom the semitendinosus tendon and the gracilis tendon were harvested (ST/G group). Results: Isokinetic testing showed that, in both the ST and ST/G groups, the knee flexor strength of the involved leg was less effectively restored at 90° of knee flexion than at the angle at which the peak torque was generated. Conversely, no significant difference was seen in the side-to-side ratio in either the peak flexion torque or the 90° flexion torque between the groups. The side-to-side ratio in mean maximum standing knee flexion angle was significantly lower in the ST/G group than in the ST group. Conclusions: This study suggests that the loss of knee flexor strength following the harvest of the hamstring tendons may be more significant than has been previously estimated. Furthermore, multiple tendon harvest may affect the range of active knee flexion.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 6 (July-August), 2002: pp 598–602     

Rotational muscle strength of the limb after anterior cruciate ligament reconstruction using semitendinosus and gracilis tendon

Purpose: To investigate the influence of harvesting semitendinosus and gracilis tendons on the rotational muscle strength of the limb after anterior cruciate ligament (ACL) reconstruction. Type of Study: Prospective study. Methods: We performed a prospective study of 62 consecutive (34 male, 28 female) patients with ACL reconstructions using the semitendinosus and gracilis tendons. The mean age at surgery was 20.8 years. The semitendinosus tendon was harvested in 32 patients (ST group), and semitendinosus and gracilis tendons in 30 patients (STG group). The peak isokinetic torques for extension, flexion, internal rotation, and external rotation were measured before and 12 months after ACL reconstruction using the Cybex 6000B system (Cybex Division of Lumex, Ronkonkoma, NY). The rotational torque was measured at 30°/sec and 120°/sec. Results: Before reconstruction, the mean isokinetic peak torque of the involved limb was decreased in extension and internal rotation. The mean isokinetic peak torque of the involved limb in extension recovered 12 months after ACL reconstruction; however, the weakness in internal rotation persisted. The preoperative weakness of the involved limb in extension and internal rotation recovered in the male patients, but not in the female patients after postoperative rehabilitation. The peak torque of the involved limb in internal rotation was decreased in the STG group, but not in the ST group. Conclusions: The internal rotational torque was influenced by harvesting the semitendinosus and gracilis tendons after ACL reconstruction, especially in female patients and patients from whom the gracilis tendon was harvested. Semitendinosus and gracilis tendons are important for the internal rotation of the limb and it was difficult to compensate for this function. Thus, we recommend harvesting the semitendinosus tendon only if tendon quality is sufficient to further minimize harvesting morbidity.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 2 (February), 2002: pp 177–182     

Quantitative evaluation of anterior tibial translation during isokinetic motion in knees with anterior cruciate ligament reconstruction using either patellar or hamstring tendon grafts

We studied 79 patients with unilateral injury to the anterior cruciate ligament (ACL). The patients were randomly allocated to reconstruction with autologous patellar bone-tendon-bone (BTB) grafts (49 knees) or hamstring tendon (ST) grafts (30 knees). We measured anterior tibial translation (ATT) during isokinetic concentric contraction exercise 18-20 months after surgery using a computerized electrogoniometer. In both groups the highest ATT during exercise was observed at a knee flexion of about 20 degrees and was 13.5+/-3.0 mm in the BTB group and 13.9+/-3.4 mm in the ST group. There was no difference in the ATT between the reconstructed and healthy knees. For a range of knee flexion between 30 and 50 degrees the ATT in the ST group was significantly higher on the reconstructed side than on the healthy side. In the BTB group, the mean ATT in the reconstructed group was similar to that on the healthy side at a knee flexion angle between 0 and 90 degrees .     

Isokinetic evaluation of anterior cruciate ligament reconstruction: hamstring versus patellar tendon.

The purpose of the study was to compare the hamstring and quadriceps isokinetic results 6 months postoperatively in patients having patellar tendon or hamstring anterior cruciate ligament (ACL) reconstruction. The study group was comprised of 106 randomly selected patients who had ACL reconstruction with either autogenous patellar tendon (PT), semitendinosus (ST), or semitendinosus and gracilis (ST/G). Hamstring and quadriceps isokinetic strength were assessed at 180 degrees/sec and 300 degrees/sec with the results of the operatively treated leg expressed as a percent compared with the nonoperative leg. The mean results for knee extension at 180 degrees/sec were 68.3%, 74.3%, and 78.1%; and at 300 degrees/sec were 70.7%, 76.7%, and 81.7% for PT, ST, and ST/G, respectively. The mean results for knee flexion at 180 degrees/sec were 86.1%, 80.6%, and 81.7%; and at 300 degrees/sec were 77.6%, 79.1%, and 75.6% for PT, ST, and ST/G, respectively. No statistically significant differences were found in regard to knee extension or flexion strength when evaluating the different tissue sources. The results show that selection of autogenous hamstring or PT used for ACL reconstruction should not be based solely on the assumption of the tissue source altering the recovery of quadriceps and/or hamstring strength. In addition, a majority of the patients had not achieved adequate strength to safely partake in unlimited activities at 6 months postoperatively.     

肌腱结嵌压固定法重建前交叉韧带生物力学实验研究

目的探讨绳肌腱结嵌压固定法重建前交叉韧带(ACL)影响初始固定效果的相关因素及对策。方法采用猪膝关节模拟重建ACL不同术式,即绳肌腱结股骨隧道嵌压固定和胫骨端肌腱编织缝合骨桥打结固定法,与骨-髌腱-骨两端界面螺钉固定法,比较其生物力学初始固定最大拔出载荷、抗拉刚度和位移等生物力学指标。结果最大抗拉载荷肌腱结组与正常ACL组接近,无显著性差异;肌腱结组大于骨-髌腱-骨界面螺钉固定组。抗拉载荷在100N和400N时的位移两组无显著性差异。胫骨端肌腱编织缝合骨桥上打结固定组最大抗拉载荷大于BPTB界面螺钉固定组和肌腱编织缝合后界面螺钉固定组。抗拉刚度正常ACL组>骨-髌腱-骨组>绳肌腱结组。最大位移正常ACL<髌腱骨组<肌腱结组。结论绳肌腱结嵌压固定法抗拉强度和刚度完全可以满足重建后ACL的生理需求;术中克服位移因素,是有效防止ACL重建术后松弛的关键。     

Changes in muscle strength properties caused by harvesting of autogenous semitendinosus tendon for reconstruction of contralateral anterior cruciate ligament

A prospective study was conducted of how the muscle strength of the donor knee is affected by harvesting of the autogenous semitendinosus tendon (St) for use as a substitute graft material in cruciate ligament reconstruction. There were 25 patients from whom only the St was harvested from the contralateral (i.e., healthy/donor) knee. Using a Biodex System II (Biodex, New York, NY), the strength of the donor knee was measured during both extension and flexion, both before and 12 months after the tendon harvesting procedure. A comparative study was made of the preharvest and postharvest values for the peak torque and peak torque angle in the isokinetic contraction. There were no statistically significant differences between the preharvest and postharvest peak torque values of the donor knee. However, the peak torque angle decreased significantly after the tendon harvest; the range of the mean decrease was from 11.7 degrees to 15.0 degrees. This indicates that there was a change to a small flexion angle (P < .05). After the tendon harvest, regardless of the applied angular velocity, more than 80% of the cases showed a change of torque curve shape in which there was no peak in the latter half, and the position of the peak was shifted to the left. In conclusion, the results of this study indicate that harvesting of the autogenous St does not affect the peak torque, but the peak torque angle during flexion of the donor knee is reduced.Arthroscopy 1998 Sep;14(6):580-4     

腘绳肌腱结嵌压固定法重建交叉韧带的临床应用与生物力学研究

目的探讨腘绳肌腱结嵌压固定法重建交叉韧带的可行性。方法对52例陈旧性前、后交叉韧带损伤患者在关节镜下行双股腘绳肌腱中间打结,嵌入瓶颈状股骨隧道内固定,胫骨端采用肌腱编织缝合在骨桥上打结固定,重建交叉韧带。其中前交叉韧带25例,前、后十字韧带同时重建15例,后交叉韧带12例。生物力学实验采用猪膝关节。股骨端固定分为肌腱结嵌入组(n=13)和骨髌腱骨(B PT B)介面螺钉固定组(B PT B介面钉组,n=11)。胫骨端固定分为肌腱编织缝合线在骨桥打结组(n=7)、肌腱编织缝合介面螺钉组(n=8)。进行最大拔出强度、最大位移和固定刚度等力学实验。结果术后随访49例,平均14 6个月,Lanchman试验阴性46例,阳性3例。术后Lysholm评分由术前56 7分提高到92 8分。按膝关节疗效评定标准,优46例,良3例。生物力学实验最大拔出强度肌腱结嵌入组高于B PT B介面钉组;固定刚度肌腱结嵌入组小于B PT B介面钉组;最大位移肌腱结嵌入组大于B PT B介面钉组。胫骨端固定抗拉强度和刚度骨桥打结组优于介面螺钉组。结论腘绳肌腱结嵌压固定重建交叉韧带生物力学抗拉强度能满足生理需求,方法可行;可克服位移因素,降低韧带松弛率,提高疗效。     

Knee flexion strength deficits correlate with distal extent of tendon regeneration after hamstring harvest. Preliminary data from an Ultrasound based classification

BackgroundAs more evidence comes to light that hamstring harvesting may not be as benign a procedure as previously thought, considerable interest is being generated towards corelating the knee flexural strength deficits with the degree of tendon regeneration. The current study aimed to corelate knee flexion strength deficits with ultrasonographically quantified degree of hamstring regeneration after tendon harvest.Study design31 patients of ACL reconstruction with hamstring grafts were divided into 2 groups (6 months and 1-year post op) according to time of follow up. Ultrasonography of both the knees to assess Semitendinosus tendon dimensions was done. Regeneration was classified as non-significant, mild (Zone 1, till 4 cm above the lateral joint line), moderate (Zone 2 ,at the level of the lateral joint line) and significant (Zone 3, 1.5 cm below the lateral joint line) as the regenerate happens from proximal to distal. Regenerate dimensions were compared with US measurements from the opposite knee. Bilateral isokinetic strength tests of the knees were done to evaluate flexion strength, and strength deficits were compared with degree of tendon regeneration.Results14 (45%) of cases had no regeneration at both time periods. 7 patients (41%) in the 6-month post-op group showed some form of regeneration, and 10 patients (71%) in the 1-year post-op group showed regeneration. 29/31 patients had some flexion strength deficit. Strength deficit correlated with the level and degree of tendon regeneration, with non-significant regeneration cases showing higher strength deficit (mean - 28.51%), and cases with significant regeneration showing least amount of strength deficit (mean - 3.66%).ConclusionFlexion strength deficits after hamstring harvest are significant and corelate with degree of tendon regeneration, which improves over time. US is adequate to quantify degree of tendon regeneration, which in turn can help prognosticate return of flexion strength.     

Prospective clinical comparisons of semitendinosus versus semitendinosus and gracilis tendon autografts for anatomic double-bundle anterior cruciate ligament reconstruction

Background

The data available from the previously reported clinical studies remains insufficient concerning the hamstring graft preparation in double-bundle anterior cruciate ligament (ACL) reconstruction.

Objective

To test the hypothesis that there are no significant differences between the semitendinosus tendon alone and the semitendinosus and gracilis tendon graft fashioning techniques concerning knee stability and clinical outcome after anatomic double-bundle ACL reconstruction.

Methods

A prospective study was performed on 120 patients who underwent anatomic double-bundle ACL reconstruction according to the graft fashioning technique. The authors developed the protocol to use hamstring tendon autografts. When the harvested doubled semitendinosus tendon is thicker than 6 mm, each half of the semitendinosus tendon is doubled and used for the anteromedial (AM) and posterolateral (PL) bundle grafts (Group I). On the other hand, when the harvested semitendinosus tendon is under 6 mm in thickness, the gracilis tendon is harvested additionally. The distal half of the semitendinosus and gracilis tendons are doubled and used for the AM bundle graft, and the remaining proximal half of the semitendinosus tendon is doubled and used for the PL bundle grafts (Group II). Sixty-one patients were included in Group I, and 59 patients in Group II. The two groups were compared concerning knee stability and clinical outcome 2 years after surgery.

Results

The postoperative side-to-side anterior laxity averaged 1.3 mm in both groups, showing no statistical difference. There were also no significant differences between the two groups concerning the peak isokinetic torque of the quadriceps and the hamstrings, the Lysholm knee score, and the International Knee Documentation Committee evaluation.

Conclusion

There were no significant differences between the two graft fashioning techniques after anatomic double-bundle ACL reconstruction concerning knee stability and postoperative outcome. The present study provided orthopedic surgeons with important information on double-bundle ACL reconstruction with hamstring tendons.

Level of evidence

Level II; prospective comparative study.     

Biomechanical evaluation of patellar- and hamstring tendon graft fixation for anterior cruciat ligament reconstruction using a poly-(D, L-lactide) interference screw

Anterior cruciate ligament (ACL) reconstruction using autologous hamstring tendons are being performed more frequently and satisfactory results have been reported. Advantages such as low donor site morbidity and ease of harvest as well as disadvantages like low initial construct stiffness have been described. Recently, it has been demonstrated that graft fixation close to the original ACL insertion sites increases anterior knee stability and graft isometry. Hamstring tendon fixation techniques using interference screws offer this possibility. To reduce the risk of graft laceration, a round threaded titanium interference screw (RCI) was developed. To improve initial fixation strength, fixation techniques for hamstring tendons with separate or attached tibial bone plugs were introduced. However, data on fixation strength do not yet exist. With respect to the proposed advantages of biodegradable implants, like undistorted magnetic resonance imaging, uncompromised revision surgery and a decreased potential of graft laceration during screw insertion, we performed pullout tests of round threaded biodegradable and round threaded titanium interference screw fixation of semitendinosus (ST) grafts with and without distally attached tibial bone plugs. Data were compared with bone-tendon-bone (BTB) graft fixation using biodegradable and conventional titanium interference screws. We used 56 proximal calf tibiae to compare maximum pullout force, screw insertion torque, and stiffness of fixation for biodegradable direct ST tendon and bone plug fixation (group I: without bone plug, group II: with bone plug) versus titanium interference screw fixation (group III: without bone plug, group IV: with bone plug). A round threaded biodegradable poly-(D, L-lactide) (Sysorb) and a round threaded titanium interference screw (RCI) were used. As a control calf bone-tendon-bone (BTB) grafts fixed with either poly-(D, L-lactide) (group V) or conventional titanium (group VI) interference screws were used. ST tendons were harvested either with or without their distally attached tibial bone plugs from human cadavers and were folded to a three-stranded graft. Specimen were loaded in a material testing machine with the applied load parallel to the long axis of the bone tunnel. Maximum pullout force of ST bone plug (group III: 717 N +/- 90, group IV: 602 N +/- 117) fixation was significantly higher than that of direct tendon (group I: 507 N +/- 93, group III: 419 N +/- 77) fixation. Maximum pullout force of biodegradable screw ST fixation was higher than that of titanium screw fixation in both settings. There was no significant difference in pullout force between biodegradable (713 N +/- 210) and titanium (822 N +/- 130) BTB graft fixation or between ST fixation with bone plug and biodegradable screw with BTB fixation. Pullout force of hamstring tendon interference screw fixation can be improved by using a biodegradable implant. In addition, initial pullout force can be greatly improved by harvesting the hamstring tendon graft with its distally attached tibial bone plug. This may be important, especially in improving tibial graft fixation. This study encourages further research in tendon-bone healing with direct interference screw fixation to confirm the potential of this advanced method.     

Quadrupled bone-semitendinosus ACL reconstruction: a prospective clinical investigation in 100 patients

Abstract The hypothesis of our study was that a quadrupled bonesemitendinosus tendon graft could combine the advantage of bone-tobone healing with the high cross-sectional area of a quadrupled hamstring graft in ACL reconstruction. ACL reconstruction with a semitendinosus tendon graft was performed on 100 patients with isolated ACL injury from January 1996 to December 1999: femoral fixation was obtained with Endobutton and tibial fixation with Fastlok. Patients were evaluated for standard knee scores and functional strength tests, postoperative pain rating, knee radiographs taken after surgery and at final follow-up, magnetic resonance images at 3 and 6 months, isokinetic flexion-extension and internal-external rotation tests at 3, 6, and 12 months. Computerized laxity analysis was performed at final evaluation. Average surgical time was 85 minutes, including 13 minutes for graft preparation; 90% of the patients were discharged within 24 h. Subjective knee rating was 80%; kneeling test was positive in 7% and Werner score was 44 (range, 30–48). Lachman test was negative in 90% at final evaluation (mean follow-up, 38 months). Sensory changes at the anterior part of the proximal tibia were present in 30% at 3 months and 10% had definite hyposthesia. MRI showed graft incorporation at 3 months. Computerized laxity analysis revealed 90% with less than 3-mm side-to-side differences. Isokinetic testing showed normal hamstring and quadriceps peak torques at 12 months. The functional strength tests were normal by 6 months. Average Noyes score was 87.9, Lysholm score 93, and Tegner activity rating 6.0 (pre-injury, 6.1). IKDC score showed 90 normal or nearly normal knees, 9 abnormal, and one severely abnormal knee. Quadrupled bone-semitendinosus is a viable graft for ACL reconstruction and should be considered, especially in patients with pre-existing extensor mechanism problems.     

Semitendinosus tendon regeneration after anterior cruciate ligament reconstruction: can we use it twice?

Purpose

It has been demonstrated that the semitendinosus tendon can regenerate after being harvested in its whole length and thickness for anterior cruciate ligament (ACL) reconstruction. Ultrasound studies and guided biopsies of the regenerated tendon have shown compatibility and resembling features of the normal tendon. The question is if this neo-tendon is biologically and functionally adequate for re-use?

Methods

Two randomised groups of 150 volunteers were followed up for two years after harvesting the semitendinosus only (25) or the semitendinosus and gracilis tendons (25) in ACL reconstruction. The patients were followed up with clinical and ultrasound examinations, biopsies and histological tests. Surgical exploration was done in three patients for macroscopic verification. The injected arteries of four lower limbs were dissected and the tendon’s arterial supplies were examined.

Results

Seventy-two percent of the cases showed regeneration of the semitendinosus tendons. The neotendons were inserted mostly below the knee joint (83.3 %) where they had fused with the gracilis tendon, and above the joint (60 %) when the gracilis was harvested as well. The isokinetic strength of the hamstrings and quadriceps was not significantly diminished on the operated side. A macroscopic and histological analysis of the regenerated tendons demonstrates close resemblance to normal anatomy, with focal areas of fibrosis. In one patient the regenerated tendon was used for medial patellofemoral ligament reconstruction.

Conclusion

The semitendinosus muscle can recover and the tendon has great potential to regenerate after harvesting for ACL reconstruction. Our data suggest that the regenerated tendons could be used for iterative ligament reconstruction.     

关节镜下髌韧带和六股异体腘绳肌腱单束重建前交叉韧带的临床研究

目的 比较关节镜下采用髌韧带和六股异体腘绳肌腱单束重建前交叉韧带的临床效果.方法 回顾性分析2006年10月至2009年12月我科采用关节镜下异体移植物单束重建前交叉韧带(ACL)的108例患者的临床资料,其中六股异体腘绳肌腱58例(腘绳肌腱组),异体髌韧带50例(髌韧带组).术后应用Lachman和pivot-shift试验以及KT-1000评估膝关节稳定性,按照国际膝关节评分委员会(IKDC)、Lysholm膝关节评分评价膝关节功能.结果 术后患者随访时间12～38个月,平均为28.6个月.腘绳肌腱组KT-1000检查示双侧膝关节前向松弛度差异为(1.2±1.2)mm,显著小于髌韧带组(1.8±1.5)mm,差异具有统计学意义(P＜0.05).腘绳肌腱组轴移试验阴性55例(94.8%),阳性3例(5.2%),髌韧带组阴性41例(82.0%),阳性9例(18.0%),差异具有统计学意义(P＜0.05).术后腘绳肌腱组和髌韧带组IKDC评分为(90±5)分和(89±5)分,Lysholm评分为(94±5)分和(93±6)分,两组比较差异无统计学意义(P＞0.05).结论 关节镜下单束重建前交叉韧带采用六股异体腘绳肌腱较髌韧带能够明显提高膝关节稳定性.

Abstract：

Objective To compare the outcome of arthroscopic single-bundle anterior cruciate ligament(ACL)reconstruction with six-strand hamstring tendon and patellar tendon allograft.Methods From October 2006 to December 2009,108 patients with arthroscopic single-bundle ACL reconstruction were retrospectively reviewed,with 58 patients with six-strand hamstring tendon(Group H),and 50 patients with patellar tendon allograft(Group P).Patients were available for clinical evaluation with KT-1000 arthrometer measurements,Lachman and pivot-shift test,and knee function with the Internationa]Knee Documentation Committee(IKDC),Lysholm scores.Results All the patients were followed up at an average of 28.6 months(range 12-38 months).The average side-to-side difference was lesser for group H(1.2 ± 1.2)mm than group P(1.8 ±1.5)mm(P＜0.05).On the pivot-shift test,55(94.8%)patients were negative and 3(5.2%)were positive in group H,whereas 41(82.0%)were negative and 9(18.0%)were positive in group P,with significant difference between two groups(P＜0.05).All knee function scores were improved postoperatively,without statistically significant difference between the two groups(P＞0.05).Conclusion Arthroscopic single-bundle ACL reconstruction with six-strand hamstring tendon will achieve better knee stability than patellar tendon allograft.     

Premature hamstring graft amputation during harvesting in ACL reconstruction

IntroductionThere are some possible complications during or after hamstring graft harvesting such as premature graft amputation, medial collateral ligament injury and infrapatellar branch of the saphenous nerve injury. Premature graft amputation can occur by inadequate removal of the accessory branches of the hamstring tendons, poor surgical technique and/or too sharp tendon stripper. In this study, we report a case of premature hamstring graft amputation due to degeneration caused by osteochondroma at the posteromedial aspect of the proximal tibia.Case presentationWe reported the case of a 28-year-old Thai male who had an ACL injury was scheduled for ACL reconstruction. In this case, we had planned to use a hamstring graft for double-bundle ACL reconstruction. During the gracilis tendon harvesting, the graft was prematurely amputated by a tendon stripper at the level of the osteochondroma. The premature graft amputation was sent for pathology, which showed degenerated tissue.ConclusionIn cases of osteochondroma at the posteromedial aspect of the proximal tibia, it is a chance of premature hamstring graft amputation. We suggest removing the osteochondroma before harvesting the tendon grafts to avoid the risk of premature graft transection.     

Donor-site morbidity and anterior knee problems after anterior cruciate ligament reconstruction using autografts

The authors review the current knowledge on donor site–related problems after using different types of autografts for anterior cruciate ligament (ACL) reconstruction and make recommendations on minimizing late donor-site problems. Postoperative donor-site morbidity and anterior knee pain following ACL surgery may result in substantial impairment for patients. The selection of graft, surgical technique, and rehabilitation program can affect the severity of pain that patients experience. The loss or disturbance of anterior sensitivity caused by intraoperative injury to the infrapatellar nerve(s) in conjunction with patellar tendon harvest is correlated with donor-site discomfort and an inability to kneel and knee-walk. The patellar tendon at the donor site has significant clinical, radiographic, and histologic abnormalities 2 years after harvest of its central third. Donor-site discomfort correlates poorly with radiographic and histologic findings after the use of patellar tendon autografts. The use of hamstring tendon autografts appears to cause less postoperative donor-site morbidity and anterior knee problems than the use of patellar tendon autografts. There also appears to be a regrowth of the hamstring tendons within 2 years of the harvesting procedure. There is little known about the effect on the donor site of harvesting fascia lata and quadriceps tendon autografts. Efforts should be made to spare the infrapatellar nerve(s) during ACL reconstruction using patellar tendon autografts. Reharvesting the patellar tendon cannot be recommended due to significant clinical, radiographic, and histologic abnormalities 2 years after harvesting its central third. It is important to regain full range of motion and strength after the use of any type of autograft to avoid future anterior knee problems. If randomized controlled trials show that the long-term laxity measurements following ACL reconstruction using hamstring tendon autografts are equal to those of patellar tendon autografts, we recommend the use of hamstring tendon autografts because there are fewer donor-site problems.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 9 (November-December), 2001: pp 971–980     

Morphology of hamstring torque‐time curves following acl injury and reconstruction: mechanisms and implications

The purposes of this study were (i) to examine the effects of anterior cruciate ligament (ACL) status on hamstring force steadiness, peak hamstring strength, quadriceps (antagonist) activation, and physical performance, and (ii) to evaluate the associations of physical performance with hamstring steadiness and hamstring strength. Thirteen subjects with unilateral deficiency of the ACL (ACLD), 39 matched subjects with unilateral reconstructed ACL (ACLR; n = 25 with bone‐patella tendon‐bone (ACLR‐PT) graft and n = 14 with combined semitendinosus and gracilis tendon (ACLR‐STGT) graft) and 33 control subjects participated. Each subject performed maximal‐effort isokinetic knee flexion repetitions at 180° s^?1 with electromyography (EMG) electrodes attached to their medial and lateral quadriceps muscles. Physical performance was assessed using the single‐limb long hop for distance. Wavelet‐derived mean instantaneous frequency (Mif) of flexor torque‐time curves was significantly (p < 0.05) higher (i.e., less smooth) in ACLR‐STGT subjects compared to the ACLD, ACLR‐PT and control subjects. No significant differences existed for peak hamstrings strength (i.e., peak torque produced) or quadriceps antagonist EMG activity. Positive correlations were identified between hamstrings force steadiness and quadriceps antagonist activity for ACLD (r = 0.797), ACLR‐PT (r = 0.467), and ACLR‐STGT (r = 0.628) subjects. For ACLR‐STGT subjects, reduced hamstrings force steadiness associated with poorer long‐hop performance (r = ?0.695). Reduced steadiness amongst ACLR‐STGT subjects may reflect motor output variability of the antagonist (i.e., quadriceps dyskinesia) and/or agonist musculature—a maladaptive feature which potentially contributes to poorer single‐limb hop performance. Measures of hamstring force steadiness in combination with traditional measures of peak hamstring strength provide valuable clinical information regarding knee joint function following ACL injury/ACLR. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:907–914     

Hamstring tendon anterior cruciate ligament reconstruction: does gracilis tendon harvest matter?

Purpose

Hamstring tendon grafts are a popular choice for anterior cruciate ligament (ACL) reconstruction. Typical morbidity reported after hamstring tendon harvest is muscle weakness in flexion, and whilst still a matter for debate, this morbidity may be greater if the gracilis tendon is harvested in addition to the semitendinosus. This study sought to comprehensively compare the outcome of ACL reconstructions in which the semitendinosus was harvested alone (ST group) or with the gracilis (ST/G group).

Methods

Twenty patients (ten ST, ten ST/G) were assessed with a variety of measures that included subjective scores, function, strength and tibial rotation as measured by gait analysis during a pivoting task.

Results

Results showed that the graft diameter was significantly larger in the ST group, but there were no other differences between the groups for any other outcome measure.

Conclusion

Harvesting the gracilis in addition to semitendinosus does not appear to affect either the outcome or graft-related morbidity after hamstring ACL reconstruction.     

自体腘绳肌腱鞘内重建前交叉韧带的临床观察

目的：观察在自体腘绳肌腱重建前交叉韧带（anterior cruciate ligament,ACL）手术中,保留原ACL胫骨残端的鞘内重建方法,对术后2年膝关节功能的影响。方法：2007年1月至2009年6月,江苏省昆山市中医院骨科收治的ACL损伤病例中,经关节镜下证实ACL胫骨端韧带残端保留1/3以上18例,男11例,女7例;平均年龄28.2岁（18～42岁）;从第1次受伤到术前平均6.8个月（1～18个月）。取自体腘绳肌腱（半腱肌腱和股薄肌腱）分别对折后编织成移植物备用。保留ACL胫骨残端,制备股骨和胫骨隧道后,将移植物经ACL残端纤维束内引入骨隧道,ACL残端呈鞘状包绕移植物。股骨端Rigidfix固定,胫骨端Intrafix固定。记录术后最后一次随访时的Lysholm评分,以评价膝关节功能;同时评价患者膝关节的稳定性和活动度;并通过再成角试验评估患膝本体感觉功能。结果：18例均获随访,时间15～24个月,平均17.3个月,术后无滑膜炎、韧带再断裂、活动明显受限等并发症。术前和术后最后一次随访时Lysholm评分,分别为（49.43±2.85）分和（91.56±4.60）分（P〈0.05）。术后最后一次随访时在屈膝15°、30°、45°位置的再成角试验,患侧与健侧差异无统计学意义（P〉0.05）。结论：保留原有残端的ACL重建术,能有效恢复膝关节功能,并有利于本体感觉的重建。     

In vitro comparison of elongation of the anterior cruciate ligament and single- and dual-tunnel anterior cruciate ligament reconstructions.

This study evaluated strain in the normal anterior cruciate ligament (ACL) and compared it to four different double-strand hamstring tendon reconstructive techniques. Seventeen fresh-frozen knees from 11 cadavers were tested. The strain in the anteromedial and posterolateral bands of the native ACL and their equivalents in four autograft techniques were measured using differential variable reluctance transducers. The anteromedial band of the intact ACL shortened from 0 degree -30 degrees of flexion, then lengthened to 120 degrees; the posterolateral band of the intact ACL shortened from 0 degree - 120 degrees of flexion. Following ACL excision, these knees underwent reconstruction with double-strand hamstring tendons with either single tibial and femoral tunnels, single tibial and dual femoral tunnels, dual tibial and single femoral tunnels, or dual tibial and dual femoral tunnels. With the exception of the dual-band, dual-tunnel technique, all of the procedures placed greater strain on the reconstructive tissues than was observed on the native ACL, after approximately 30 degrees of flexion. These results indicate that dual-band hamstring tendon reconstructions placed with single tibial and femoral tunnels do not address the complexity of the entire ACL. Rather, these procedures appear to only duplicate the effect of the anteromedial band, while perhaps overconstraining the joint as a result of its inability to reproduce the function of the posterolateral band. During rehabilitation following ACL reconstruction, therefore, only from 0 degree - 30 degrees of the graft tissues are not significantly strained. Dual tibial and femoral tunnel techniques should be evaluated further to more closely recreate knee kinematics following ACL reconstruction.     

膝关节镜下自体腘绳肌腱和同种异体肌腱移植重建前交叉韧带对比观察

目的：探讨关节镜下同种异体肌腱和自体腘绳肌腱重建前交叉韧带的疗效。方法：收集32例前交叉韧带损伤病例,单纯前交叉韧带（ACL）损伤29例,与后交叉韧带（PCL）同时损伤3例。分为2组,同种异体肌腱重建15例,男12例,女3例,年龄23～61岁;自体腘绳肌腱重建17例,男11例,女6例,年龄17～57岁。用可吸收或钛挤压螺钉固定,观察并记录治疗后的症状、体征变化和Lysholm评分以及术后6个月的功能康复情况。结果：全部病例均获得随访,时间6～8个月,所有病例无膝前区疼痛,临床症状消失,膝关节功能得到改善。同种异体肌腱重建前交叉韧带5例患者仍出现Lachman征阳性体征,其中1例产生严重的排斥反应,关节镜复查韧带完全吸收。2组患者治疗后Lysholm评分分别为平均（88.5±7.2）分和（93.2±8.5）分,差异无统计学意义（P〉0.05）。结论：关节镜下两种方法重建前交叉韧带都有较好的疗效,同种异体肌腱重建交叉韧带早期有更多的症状,有明显的个体差异,重建交叉韧带尽可能选用自体腘绳肌腱。