Intra-articular remodelling of hamstring tendon grafts after anterior cruciate ligament reconstruction

Purpose

A summary is provided on the existing knowledge about the specific healing phases of the intra-articular hamstring tendon graft used for ACL reconstruction. Differences between human and animal in vivo studies are explained, and implications for the postoperative time period are laid out.

Methods

A systematic review of the existing literature was performed on the topic of tendon remodelling of hamstring grafts in ACL reconstruction using Medline database. Publications between 1982 and 2012 were included. Special focus was directed on in vivo human and animal studies analysing intra-articular free tendon graft remodelling.

Results

Animal and human in vitro and vivo researches have demonstrated three characteristic stages of graft healing after ACL reconstruction: an early graft healing phase with central graft necrosis and hypocellularity and no detectable revascularization of the graft tissue, followed by a phase of proliferation, the time of most intensive remodelling and revascularization and finally, a ligamentization phase with characteristic restructuring of the graft towards the properties of the intact ACL. However, a full restoration of either the biological or biomechanical properties of the intact ACL is not achieved.

Conclusion

Significant knowledge on human cruciate ligament remodelling has been added in the understanding of the processes during the course of graft healing. Most importantly, the remodelling process in humans is prolonged compared to animal studies. While today´s rehabilitation protocols are often extrapolated from findings of animal in vivo healing studies, current findings of human in vivo healing studies might require new post-operative regimens following hamstring ACL reconstruction.     

Comparisons of femoral tunnel enlargement in 169 patients between single-bundle and anatomic double-bundle anterior cruciate ligament reconstructions with hamstring tendon grafts

Purpose  

Authors have hypothesized that the incidence and the degree of femoral tunnel enlargement after the hamstring ACL reconstruction may be significantly less in the anatomic double-bundle procedure than in single-bundle procedure. The purpose of this study is to test this hypothesis.     

Interference screw fixation of hamstring vs patellar tendon grafts for anterior cruciate ligament reconstruction

The present study was designed to investigate the fixation strength of a quadruple semitendinosus-gracilis graft compared with a middle-third bone-patellar tendon-bone graft using a new interference screw developed to fix hamstrings grafts for ACL reconstructions (RCI, Smith & Nephew Donjoy). Five pairs of human cadaveric knees from donors with a mean age of 43 (range 33–52) years were used. One knee of each pair was randomly allocated to be reconstructed on the femoral side with a semitendinosus-gracilis graft from the same donor using RCI screw fixation. As the control, the contralateral knee was correspondingly reconstructed with a bone-patellar tendon-bone graft using the same interference screw. The grafts were pulled out at a velocity of 30 mm/s by an axially applied load using a MTS machine. The mean (SD) failure load for the bone-patellar tendon-bone graft fixations was 505 (25) N, 110% stronger than the mean failure load for the semitendinosus-gracilis graft fixations, which was 240 (47) N (P = 0.003). The stiffness for the patellar tendon-bone graft fixations was 46 (11) N/mm, 120% stiffer than the semitendinosus-gracilis graft fixations, which was 22 (11) N/mm (P = 0.01). This study shows that the interference screw principle used for ACL reconstructions with hamstrings tendons is inferior to that for bone-patellar tendon-bone reconstructions although the screw was developed especially for soft-tissue fixation in bone tunnels. Received: 14 August 1996 Accepted: 25 September 1997     

Arthroscopic anterior cruciate ligament reconstruction with periosteum-enveloping hamstring tendon graft

Tendon–bone incorporation of a tendon graft within the bone tunnel is of priority concern when using for anterior cruciate ligament (ACL) reconstruction. Superior healing process and stronger healing strength can be achieved when periosteum is sutured on the tendon inserted into a bone tunnel. We applied this idea to ACL reconstruction for enhancing tendon graft–bone tunnel healing. This is a prospective clinical outcome study with this surgical technique at minimal 2 years follow-up. Periosteum-enveloping hamstring tendon graft has been used in 68 patients. Data from 62 patients who had been followed up completely were analyzed. All patients suffered from a grade 3 or higher grade of Lachman and anterior drawer test with a positive pivot-shift test. Clinical assessments included the Lysholm knee scores, International Knee Documentation Committee (IKDC) scores, KT-1000 instrumented testing, thigh muscle assessment, and radiographic evaluation. The median Lysholm knee score was 59 (40–70) and 94 (60–100) points (P<0.01) before and after surgery. After reconstruction, 81% of patients were able to return to moderate or strenuous activity. Four (6%) patients were found to exhibit grade 2 or more ligament laxity. Complete range of motion could be achieved in 86% of patients. Three patients (5%) had positive pivot shift. Finally, 92% of patients were assessed as normal or nearly normal rating by IKDC guideline. Bone tunnels enlargement of more than 1 mm was identified in 5% of femoral tunnels and 6% of tibial tunnels. The study shows that a satisfactory result can be achieved with the periosteum-enveloping hamstring tendon graft in ACL reconstruction. Periosteum can be easily harvested at the proximal tibia from a routine incision for hamstring tendon harvesting. Besides the potential for improving tendon–bone healing, enveloped periosteum may help to seal the intra-articular tunnel opening in the early postoperative period, and thus avoid synovial fluid reflux into the tunnel. Bone tunnel enlargement could be reduced.     

Regeneration of hamstring tendons after anterior cruciate ligament reconstruction

Purpose

Primary aim of the study was analysis of hamstring tendon regeneration after anterior cruciate ligament reconstruction (ACLR). Secondary aim was analysis of isokinetic muscle strength in relation to hamstring regeneration. The hypothesis was that regeneration of hamstring tendons after ACLR occurs and that regenerated hamstring tendons contribute to isokinetic hamstring strength with regeneration distal to the knee joint line.

Methods

Twenty-two patients scheduled for ACLR underwent prospective MRI analysis of both legs. MRI parameters were tendon regeneration and morphology, muscle retraction and muscle cross-sectional area. A double-blind, prospective analysis of isokinetic quadriceps and hamstrings strength was performed.

Results

Regeneration of the gracilis tendon after ACLR occurred in all patients. Regeneration of the semitendinosus tendon occurred in 14 patients. At 1 year, the surface area of the semitendinosus and gracilis muscle decreased compared to both preoperatively (P < 0.01) and the contralateral leg (P < 0.01). The cross-sectional area of the semitendinosus muscle decreased in the absence of tendon regeneration (P = 0.05). The cross-sectional area of the gracilis muscle was greater in case of regeneration distal to the joint line (P = 0.01). Muscle retraction of the semitendinosus muscle was increased in case of nonregeneration (P = 0.02). There was no significant relationship between isokinetic flexion strength and tendon regeneration.

Conclusion

Hamstring tendons regenerated after harvest of both semitendinosus and gracilis tendons for ACLR. There was no relation between isokinetic flexion strength and tendon regeneration.

Level of evidence

Prognostic study, Level II.     

关节镜下微创自体腘绳肌腱重建前交叉韧带

目的探讨关节镜下自体腘绳肌腱单束重建膝关节前交叉韧带的疗效。方法自2011年3月至2013年9月,我科对115例膝关节前交叉韧带断裂患者采用关节镜下自体腘绳肌腱、Endo-button和Intra-fix内固定系统,单束重建膝关节前交叉韧带。结果术后随访12~30个月(平均19个月)。按Lysholm标准评价,术前平均(51.65±1.71)分,术后平均(91.26±2.25)分,术前、术后评分比较差异有统计学意义(P<0.05)。结论关节镜下自体腘绳肌腱、Endo-button和Intrafix内固定系统单束重建膝关节前交叉韧带,创伤小,并发症少,术后恢复快、关节功能恢复良好,疗效确切,是重建膝关节前交叉韧带的有效方法。     

Results of knee manipulations after anterior cruciate ligament reconstructions

We analyzed the results of knee manipulations in 42 knees that had persistent flexion or extension deficits after intraarticular ACL reconstructions. All manipulations were done under a spinal or general anesthetic and, in 10 cases, arthroscopic debridement of adhesions also was performed. The average time from reconstruction to manipulation was 7 months (range, 3 to 14 months) and the average followup was 26 months (range, 6 to 56 months). At manipulation, average flexion was increased from 95 degrees to 136 degrees and average extension from 11 degrees to 3 degrees. In no case was motion gained at the expense of joint stability and, at final followup, average flexion and extension were 127 degrees and 4 degrees, respectively. The final range of motion achieved was not affected by the time to manipulation, severity of premanipulation flexion deficit, or concomitant arthroscopic debridement of adhesions. However, knees with premanipulation extension deficits of greater than or equal to 15 degrees achieved significantly less final extension than knees with lesser premanipulation deficits. Overall, manipulations were a safe and effective method for improving both flexion and extension in 86% of the knees that had restricted motion after ACL reconstructions.     

The normal anterior cruciate ligament as a model for tensioning strategies in anterior cruciate ligament grafts

BACKGROUND: There is some confusion about the relationship between the tension placed on the graft and the joint position used in the fixation of anterior cruciate ligament grafts. This is because of deficiency in accurate basic science about this important interaction in the normal and reconstructed anterior cruciate ligament. HYPOTHESIS: If the normal femoral attachment of the anterior cruciate ligament can be preserved and the tibial insertion isolated and tested, an accurate force-flexion curve of the human anterior cruciate ligament can be mapped out and used as a standard for proper graft tensioning protocols in anterior cruciate ligament reconstruction. STUDY DESIGN: Controlled laboratory study. METHODS: In 10 fresh-frozen human cadaveric knees, an isolated bone plug containing the tibial anterior cruciate ligament insertion was connected with a custom-made tensiometer. The knees were moved through the whole range of motion; the starting point chosen was an anterior cruciate ligament tension of 10 N, which was applied at 10 degrees of knee flexion and resulted in a baseline curve. This curve was compared with the results recorded when the starting point was below the baseline curve, similar to, or above it. RESULTS: The anterior cruciate ligament showed low tension close to slackness in midflexion after starting with 10 N at 10 degrees of flexion. Starting points below the baseline curve shifted the whole curve downward; those above the baseline curve increased the force in the anterior cruciate ligament, resulting in a tight anterior cruciate ligament in midflexion. CLINICAL RELEVANCE: The normal anterior cruciate ligament shows a physiological laxity in midflexion. This study gives guidelines for tensioning protocols in anterior cruciate ligament grafts to replicate the force-flexion curve characteristics of the normal anterior cruciate ligament.     

Tibial tunnel widening after anterior cruciate ligament reconstructions with hamstring tendons using Rigidfix femoral fixation and Intrafix tibial fixation

The purpose of this study was to evaluate tibial tunnel widening prospectively after anterior cruciate ligament (ACL) reconstruction with hamstring tendon grafts using Rigidfix (DePuy Mitek, Raynham, MA) femoral fixation and Intrafix (DePuy Mitek) tibial fixation. Fifty-six consecutive patients who underwent ACL reconstruction with a minimum of 2 years’ postoperative evaluation were reviewed. On the anterior–posterior (AP) and lateral radiographs, the diameter of the tibial tunnel was measured at proximal, middle, and distal positions, and the shape of the tibial tunnels were classified. Tunnel widening was defined as widening of greater than 2 mm. Group I was defined as cases with no tunnel widening, and group II was defined as cases with tunnel widening. Postoperative laxity evaluations were performed using Lachman test, pivot-shift test, and instrumented laxity testing using the KT-1000 arthrometer. On the AP radiographs, the average diameter of the tibial tunnel increased 8.8% at 6 months and 8.5% at 12 months postoperatively compared to the immediate postoperative day. On the lateral radiographs, the average diameter of the tibial tunnel increased 7.2% at 6 months and 8.1% at 12 months year postoperatively compared to the immediate postoperative day. The tunnel shape evaluation revealed predominantly linear type in 53 patients (95%). Group I was 42 patients (75%), and group II was 14 (25%). The average KT-1000 measurement was 1.0 ± 1.8 mm in group I and 2.1 ± 2.8 mm in group II (n.s.). The Lachman and pivot-shift tests showed no significant differences between the two groups. In conclusion, hamstring ACL reconstruction using Rigidfix and Intrafix fixation showed less widening of the tibial tunnels than observed in previously published studies.     

A prospective comparison of bone-patellar tendon-bone and hamstring grafts for anterior cruciate ligament reconstruction in female patients

The aim of the study is to compare the results after arthroscopic anterior cruciate ligament (ACL) reconstruction using central-third, bone-patellar tendon-bone (BTB group) (n=28) and four-strand semitendinosus/gracilis (ST/G group) (n=31) autografts in female patients. The type of study was non-randomised prospective consecutive series. A consecutive series of 61 female patients, all with unilateral ACL ruptures, was included in the study. In both groups, interference screw fixation of the graft was used at both ends, and 59/61 (97%) of the patients returned for the follow-up examination after a period of 26 (23–31) months. The pre-operative assessments in both groups were similar in terms of the Lysholm score, KT–1000 measurements, one-leg-hop test, and knee-walking test. At the 2-year follow-up, the knee-walking test was significantly worse in the BTB group than in the ST/G group (P=0.003). Furthermore, the knee-walking test was significantly worse at follow-up than pre-operatively in the BTB group (P<0.005). The corresponding finding was not made in the ST/G group. A reduction in knee laxity compared with the pre-operative assessments was found in both groups. No significant difference in the post-operative knee laxity measurement was found between the groups. A significant increase in activity level and subjective scores was found in both groups compared with pre-operative values, without any significant differences between the groups. Two years after ACL reconstruction, the groups displayed no significant differences in terms of functional outcome and knee laxity. However, the use of ST/G autografts rendered significantly less discomfort during the knee-walking test than the use of BTB autografts.     

Tunnel widening in anterior cruciate ligament reconstruction: a prospective evaluation of hamstring and patella tendon grafts

We report a prospective series evaluating the incidence and degree of tunnel widening in a well-matched series of patients receiving a hamstring or patella tendon graft for anterior cruciate ligament (ACL) deficiency. We correlated tunnel widening with clinical factors, knee scores, KT-1000 and isokinetic muscle strength to determine the clinical significance of this finding. Seventy-three patients at least 12 months post-ACL reconstruction were evaluated. Thirty-eight patients had received a doubled semitendinous and gracilis graft and 35 a bone-patella tendon-bone graft. All patients underwent a similar endoscopic procedure and accelerated postoperative rehabilitation. Tunnel widening was determined using standardized anteroposterior (AP) and lateral X-rays adjusted for magnification. A limited series of MRIs was performed to validate these measurements. There was a significant difference in the degree of tunnel widening between the two groups. The mean increase in femoral tunnel area in the hamstring group was 100.4% compared with a decrease of 25% in the patella tendon group (P = < 0.0001). In the tibial tunnel the mean increase in the hamstring group was 73.9% compared with a decrease of 2.1% in the patella tendon group (P = < 0.0001). The MRIs validated the plain film measurements. Tunnel widening did not correlate with the clinical findings, knee scores, KT-1000 or isokinetic muscle strength. Tunnel widening is marked in the hamstring group. Tunnel widening does not correlate with instability or a poor clinical outcome in the short term. The long-term implications of this finding are still to be determined. Received: 11 March 1998 Accepted: 14 September 1998     

Prevalence of anterior cruciate ligament reconstructions in professional soccer players

Abstract In the literature there are many studies on soccer injuries, but data regarding the epidemiology of anterior cruciate ligament (ACL) ruptures of professional players are scarce. The aim of this retrospective study was to investigate the prevalence and the incidence of ACL surgical reconstructions of top-level professional soccer players. A questionnaire was administered by the sports physicians of the 18 teams competing in the 2002–2003 Italian Serie A Championship to players who reported in their career one or more ACL reconstructions. The prevalence of ACL reconstructions was 10.4%; the incidence was 1.08 every 1000 competitive playing exposures or 0.72 every 1000 h of game. Players who reported an ACL reconstruction when younger (20.3±2.1 years) had a higher risk of ACL injury to the other side. Contact injuries were more frequent during official games, while during training or nonofficial games non-contact injuries were more frequent. These data should be considered by team physicians and coaches to prevent ACL injuries and re-injuries in professional soccer.     

前交叉韧带重建术后并发症磁共振成像表现

目的探讨前交叉韧带重建术后并发症的磁共振成像（MRI）表现。方法回顾性分析34例前交叉韧带撕裂重建术后并发症的MRI表现。结果移植物撕裂12例,其中完全撕裂5例,部分撕裂7例．移植物纤维束完全中断、断端T2wI呈高信号及移植物厚度增加是移植物完全撕裂的可靠直接征象,多量关节积液及胫骨外侧髁骨挫伤是较可靠的间接征象,部分撕裂为部分纤维束中断。移植物撞击9例,撞击点位于前部远侧2／3处并向后屈曲,撞击处移植物水肿;关节纤维化8例,弥漫性纤维化5例,局限性纤维化3例,前者T1WI和T2WI呈等一低信号,后者呈等一长T1、混杂T2信号,位于移植物前方,周围有低信号环;黏液样退变4例,位于移植物内呈长T。长T2信号,边缘清楚;螺丝脱落1例,脱落的螺丝位于髌下囊内。结论MRI能明确诊断膝关节前交叉韧带撕裂重建术后并发症,为临床早期发现和及时治疗提供客观依据。     

Intra-operative hamstring tendon graft contamination in anterior cruciate ligament reconstruction

We aimed to evaluate the possibility of hamstring tendon contamination, the correlation with clinical infection and its association with C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) values in 89 anterior cruciate ligament reconstructions. Two tissue samples were obtained for culture from each graft: immediately after harvesting the graft and before implantation. The ESR and the CRP were evaluated preoperatively and on the 4th and 20th postoperative days. Nine patients (10%) had positive cultures but no patient had signs of postoperative infection. All patients had ESR and CRP values elevated at the 4th postoperative day. ESR and CRP values returned to normal levels at the 20th postoperative day. Higher mean values of CRP levels at the 4th day were observed in patients with contaminated grafts compared to those with uncontaminated. Both values reached normal levels at the 20th postoperative day.     

MR arthrography of anterior cruciate ligament reconstruction grafts

OBJECTIVE: Our objective was to determine the accuracy of MR arthrography for identification of tears of anterior cruciate ligament reconstruction grafts and for detection of localized anterior arthrofibrosis and impingement. MATERIALS AND METHODS: We retrospectively identified 27 patients (mean age, 31 years; range, 18-45 years) with anterior cruciate ligament reconstruction who had undergone MR arthrography followed by arthroscopy within 1 year. Three radiologists independently reviewed the MR arthrograms for the presence or absence of graft tear, localized anterior arthrofibrosis, and impingement. RESULTS: Graft tears were identified with 100% sensitivity by all three reviewers with specificities of 100%, 89%, and 94%. Localized anterior arthrofibrosis was identified with 100% sensitivity by all reviewers, with specificities of 79%, 71%, and 38%. Impingement was detected with sensitivities and specificities of 83% and 100%, 83% and 52%, and 33% and 90% by the three reviewers, respectively. Interobserver agreement was almost perfect for detection of graft tear (kappa = 0.83, 0.92, and 0.83), was fair to moderate for detection of localized anterior arthrofibrosis (kappa = 0.50, 0.32, and 0.22), and was slight to fair for detection of impingement (kappa = 0.40, 0.08, and 0.35). CONCLUSION: MR arthrography can accurately depict the presence of anterior cruciate ligament graft tears. Localized anterior arthrofibrosis and graft impingement were less accurately detected and showed greater observer variability.     

Remodelling of human hamstring autografts after anterior cruciate ligament reconstruction

Purpose  

Histological analysis of the remodelling process of human hamstring tendon (HT) grafts after standardized anterior cruciate ligament reconstruction (ACLR) with an accelerated rehabilitation protocol.     

MRI of anterior cruciate ligament repair with patellar and hamstring tendon autografts

Objective. Several MRI sequences were used to evaluate the 2-year postoperative appearance of asymptomatic knee with a torn anterior cruciate ligament (ACL) reconstructed with bone–patellar tendon–bone (BTB) and semitendinosus and gracilis (STG) tendon autografts. Design and patients. Two groups with successful repair of ACL tear with BTB (n=10) or STG (n=10) autografts were imaged at 1.5 T with sagittal and oblique coronal proton density-, T2-weighted and sagittal STIR sequences and plain and contrast-enhanced oblique coronal T1-weighted sequences. The appearance of the graft and periligamentous tissues was evaluated. Results. In all 20 cases, the ACL graft showed homogeneous, low signal intensity with periligamentous streaks of intermediate signal intensity on T2-weighted images. In 10 cases, localised areas of intermediate signal intensity were seen in the intra-articular segment of the graft on proton density- and T1-weighted images. The graft itself did not show enhancement in either of the two groups, but mild to moderate periligamentous enhancement was detected in 10 cases. Conclusion. The MRI appearance of ACL autograft is variable on proton density- and T1-weighted images. Periligamentous tissue showing contrast enhancement is a typical MRI finding after clinically successful ACL reconstruction. Received: 22 February 2000 Revision requested: 27 June 2000 Revision received: 21 August 2000 Accepted: 23 August 2000     

Comparative pull-out and cyclic-loading strength tests of anchorage of hamstring tendon grafts in anterior cruciate ligament reconstruction.

This study examined four devices for anchorage of hamstring tendons used as anterior cruciate ligament grafts: a stirrup, a clawed washer and screw, and "soft" and round-headed interference screws. Ultimate strength tests were performed using bovine tendons and bones. The stirrup was significantly stronger than the other anchorage devices, failing at 898 N. The clawed washer failed at 502 N, the soft screw at 691 N, and the round-headed screw at 445 N. Cyclic loading to 150 N (to simulate walking) caused elongation of 2.1 mm with the stirrup by 1100 cycles, and 6.7 mm with the clawed washer by 300 cycles. Different hole and soft screw diameters and placements (inside-out versus outside-in) allowed 1-to 3-mm slippage (no significant differences) by 1100 cycles. The round-headed screw allowed 6.8-mm slippage by 1100 cycles, and a sharp edge below the screw head caused tendon damage. Cyclic loads to 450 N (to simulate jogging) were then imposed until failure, and all specimens failed rapidly; only stirrup fixation kept all specimens intact after 300 load cycles. We concluded that anterior cruciate ligament reconstructions using hamstring tendons will slacken if rehabilitation is too aggressive, so forces on the reconstructed ligament should be minimized until tendon-to-bone healing occurs.     

Principles for using hamstring tendons for anterior cruciate ligament reconstruction

The use of autogenous hamstring tendon as a graft source for anterior cruciate ligament (ACL) reconstruction continues to gain in popularity. The low harvest morbidity and excellent biomechanical graft properties coupled with improved fixation of soft tissue grafts are all reasons for excellent clinical outcomes of ACL reconstruction using hamstring tendons. In addition, surgeon awareness of the complications associated with poor tunnel placement and more exacting tunnel placement techniques help prevent roof and posterior cruciate ligament impingement and contribute to the successful outcomes of hamstring ACL constructs.