Graft selection for anterior cruciate ligament reconstruction: a level I systematic review comparing failure rates and functional outcomes

Hamstring graft sizes differ between Chinese and Caucasians

PURPOSE

The use of hamstring tendon autografts for anterior cruciate ligament (ACL) surgery has become more and more common. The purposes of this study were to determine whether anthropomorphic measurement correlated with tendon sizes in Chinese patient group and whether tendon sizes in Chinese and Caucasian patient groups differed.

METHODS

From 2008 to 2009, 100 patients that received double-bundle ACL reconstruction with autologous hamstring tendons were prospectively enrolled. The original lengths and triple-folded graft diameters of the individual semitendinosus (ST) and gracilis (Gr) tendons were recorded and correlated with the anthropometric data (height, weight, body mass index, gender, thigh length, shank length, leg length and bilateral thigh circumference) of the patients. Later, using height for predictions, the original heights of patients were added to the equations previously used for regression models to compare the tendon lengths in different ethnic groups.

RESULTS

After stepwise multiple linear regression analysis, the height and leg lengths showed greatest correlation with the lengths of both tendons. The lengths of both the semitendinosus and gracilis tendons in Caucasian patients were significantly longer than in the Chinese patients.

CONCLUSIONS

The results of this study showed that anthropomorphic measurements (height and leg length) correlated with tendon lengths. In addition, Caucasians had significantly longer hamstring tendons than the Chinese patients.

LEVEL OF EVIDENCE

Prospective cohort study (prevalence), Level I.

Tendon-derived stem cells (TDSCs) promote tendon repair in a rat patellar tendon window defect model

Injured tendons heal slowly and often result in the formation of mechanically and functionally inferior fibrotic scar tissue or fibrous adhesions. This study investigated the use of tendon-derived stem cells (TDSCs) for tendon repair in a rat patellar tendon window defect model. Fibrin glue constructs with or without GFP-TDSCs were transplanted into the window defect. The patellar tendons were harvested for histology, ex vivo fluorescent imaging and biomechanical test at various time points up to week 4. Our results showed that TDSCs significantly enhanced tendon healing as indicated by the increase in collagen production as shown by hematolxylin stain-ability of the tissue, improvement of cell alignment, collagen fiber alignment and collagen birefringence typical of tendon. The labeled cells were observed at weeks 1 and 2 and became almost undetectable at week 4. Both the ultimate stress and Young's modulus were significantly higher in the TDSCs group compared to those in the fibrin glue group at week 4. In conclusion, TDSCs promoted earlier and better repair in a rat patellar tendon window defect model.

Anatomic anterior cruciate ligament reconstruction utilizing the double-bundle technique

The goal of every orthopaedic surgeon should be to restore anatomy as close as possible to normal. Intense research on reconstruction of the anterior cruciate ligament (ACL) and an advancing knowledge of the anatomy and function of the 2 primary bundles of the ACL have led to techniques of ACL reconstruction that more closely restore normal anatomy. Restoring the ACL footprint is one of the most important goals of the surgery, and the choice between anatomic single-bundle and double-bundle ACL reconstruction is determined by the anatomical features of each patient. After reconstruction, the graft undergoes a complex, lengthy process of remodeling; therefore, inappropriate (early), aggressive rehabilitation can lead to graft failure and compromise the patient's outcome. The purpose of this article is to provide an overview of the anatomy and function of the ACL, the methods for anatomic single-bundle and double-bundle ACL reconstruction, and our recommendations for postoperative rehabilitation.

Single- versus double-bundle ACL reconstruction: is there any difference in stability and function at 3-year followup?

BACKGROUND

Despite a number of studies comparing postoperative stability and function after anatomic double-bundle and single-bundle anterior cruciate ligament reconstruction (ACLR), it remains unclear whether double-bundle reconstruction improves stability or function.

QUESTIONS/PURPOSES

We therefore asked whether patients having single- and double-bundle ACLR using semitendinosus (ST) alone differed with regard to (1) postoperative stability; (2) ROM; and (3) five functional scores.

METHODS

We prospectively followed 60 patients with an isolated anterior cruciate ligament (ACL) injury. Thirty patients underwent single-bundle and 30 patients underwent double-bundle ACL reconstruction. Clinically we assessed stability and range of motion (ROM); anteroposterior stability was assessed by Rolimeter and rotational stability by a pivot shift test. Function was assessed by IKDC, Noyes, Lysholm, Marx, and Tegner activity scales. The minimum followup was 36 months (mean, 46.2 months; range, 36-60 months).

RESULTS

Residual anteroposterior laxity at 3 years postoperatively was similar in both groups: 1.4 ± 0.3 mm versus 1.4 ± 0.2 mm, respectively. We observed no difference in the pivot shift test. ROM was similar in both groups, although double-bundle patients required more physical therapy sessions to gain full ROM. IKDC, Noyes, Lysholm, Marx, and Tegner scores were similar at final followup.

CONCLUSION

Double-bundle reconstruction of the ACL did not improve function or stability compared with single-bundle reconstruction.

LEVEL OF EVIDENCE

Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Complete ACL/MCL deficiency induces variable degrees of instability in sheep with specific kinematic abnormalities correlating with degrees of early osteoarthritis

People are not equally disabled by combined anterior cruciate ligament (ACL)/medial collateral ligament (MCL) injuries, nor do they all develop osteoarthritis (OA). Although biological/biomechanical causes are not clear, some association presumably exists between joint instability and OA development. We hypothesized that degree of OA development following standardized complete ACL/MCL injuries will vary directly with the degree of biomechanical abnormality between individuals. Three groups of sheep were used to test the hypothesis: 17 normal, 9 ACL/MCL transected, and 7 sham animals. Normal joints were assessed morphologically while sham and experimental animals had gait assessment pre- and at 4 and 20 weeks post-surgery, with cartilage and bone changes being mapped and graded at sacrifice at 20 weeks. Sham joints were morphologically normal and had only one minor kinematic change at 20 weeks. Although variable, ACL/MCL deficient animals showed significant kinematic abnormalities in 4/6 degrees of freedom (DOFs), as well as cartilage/bone damage by 20 weeks (p < 0.05). Linear regression analysis revealed that changes in medial-lateral (ML) translation were related to the current level of joint degradation as represented by total gross OA score (p = 0.0044, R(2)  = 0.71) in the ACL/MCL transected group. Even identical ACL/MCL injuries result in inter-animal variations in instability and OA, however significant kinematic abnormalities in ML translation do relate to early OA in sheep.

Patient and surgeon characteristics associated with primary anterior cruciate ligament reconstruction graft selection

BACKGROUND

It has been suggested that a surgeon's experience and training are the most important factors associated with graft selection, but no studies have qualified this association. Graft usage prevalence has not been described for large anterior cruciate ligament reconstruction (ACLR) populations in the United States.

PURPOSE

To describe the prevalence of graft usage in a large community-based practice and evaluate the association of patient, surgeon, and site characteristics with choice of primary ACLR graft.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Primary ACLRs performed between February 2005 and June 2010 were selected for the study. A community-based ligament registry was used to identify cases and variables used for analysis. Graft choice (any allograft, hamstring autograft, and bone-patellar tendon-bone [BPTB] autograft) was compared by patient characteristics and surgeon and site characteristics. Associations between independent variables and graft choice were evaluated using a polychotomous regression model.

RESULTS

Of the 9849 patients included in the study, 64% were male, and overall median age was 28 years. Of these, 2796 (28.4%) received BPTB autografts, 3013 (30.6%) received hamstring autografts, and 4040 (41.0%) received allografts. The prevalence of graft source by patients' gender, race, age, body mass index (BMI), as well as surgeons' fellowship training status, average volume, and site volume were significantly different (all P < .001). Adjusted models showed that patients' gender (P < .001), race (P = .018), age (P < .001), BMI (P < .001), as well as surgeons' fellowship training status (P < .001), average volume (P < .001), and site volume (P < .001) are associated with graft selection. Older and female patients with lower BMI were more likely to receive allografts and hamstring autografts than BPTB autografts. Cases performed by non-fellowship-trained surgeons, lower volume sites, and/or lower volume surgeons were also more likely to be performed with allografts or hamstring autografts than BPTB autografts.

CONCLUSION

Gender, age, race, as well as facility and surgeon characteristics such as volume and location are associated with ACL graft choices.

Clinical results of technique for double bundle anterior cruciate ligament reconstruction using hybrid femoral fixation and Retroscrew

Background

Anatomic anterior cruciate ligament (ACL) reconstruction has been presented as a means to more accurately restore the native anatomy of this ligament. This article describes a new method that uses a double bundle to perform ACL reconstruction and to evaluate the clinical outcome.

Methods

Grafts are tibialis anterior tendon allograft for anteromedial bundle (AMB) and hamstring tendon autograft without detachment of the tibial insertion for posterolateral bundle (PLB). This technique creates 2 tunnels in both the femur and tibia. Femoral fixation was done by hybrid fixation using Endobutton and Rigidfix for AMB and by biointerference screw for PLB. Tibial fixations are done by Retroscrew for AMB and by native insertion of hamstring tendon for PLB. Both bundles are independently and differently tensioned. We performed ACL reconstruction in 63 patients using our new technique. Among them, 47 participated in this study. The patients were followed up with clinical examination, Lysholm scales and International Knee Documentation Committee (IKDC) scoring system and radiological examination with a minimum 12 month follow-up duration.

Results

Significant improvement was seen on Lachman test and pivot-shift test between preoperative and last follow-up. Only one of participants had flexion contracture about 5 degrees at last follow-up. In anterior drawer test by KT-1000, authors found improvement from average 8.3 mm (range, 4 to 18 mm) preoperatively to average 1.4 mm (range, 0 to 6 mm) at last follow-up. Average Lysholm score of all patients was 72.7 ± 8.8 (range, 54 to 79) preoperatively and significant improvement was seen, score was 92.2 ± 5.3 (range, 74 to 97; p < 0.05) at last follow-up. Also IKDC score was normal in 35 cases, near normal in 11 cases, abnormal in 1 case at last follow-up.

Conclusions

Our new double bundle ACL reconstruction technique used hybrid fixation and Retroscrew had favorable outcomes.

Labeling and tracing of bone marrow mesenchymal stem cells for tendon-to-bone tunnel healing

PURPOSE

To investigate the effects of bone marrow mesenchymal stem cells (BMSCs) on tendon-to-bone tunnel healing and provide experimental evidence for labeling and tracing of stem cells.

METHODS

Rat BMSCs were harvested using the adherence separation technique and labeled by super paramagnetic iron oxide (SPIO) and 1,1-Dioctadecyl-3,3,3,3-tetramethylindocarbocyanine perchlorate (Dil) particles. Thirty-nine male Sprague-Dawley (SD) rats aged 8 weeks were randomly divided into two groups: experimental (n = 21) and control (n = 18). Rats from the experimental group were injected with SPIO- and Dil-labeled BMSCs and Pluronic F-127, and rats from the control group were only injected with Pluronic F-127. At 2, 4, and 8 weeks after surgery, biomechanical analysis was performed to evaluate tendon-to-bone tunnel healing. The transplanted BMSCs were observed by fluorescence microscope at 2, 4, and 8 weeks after surgery and traced by magnetic resonance (MR) imaging at 0, 3, and 7 days after surgery.

RESULTS

BMSCs were labeled effectively by SPIO and Dil particles. At 2, 4, and 8 weeks after surgery, Dil-labeled cells were observed at tendon-bone interface by fluorescence microscope. In the experimental group, no obvious signal changes of tendon-bone interface were observed by MR imaging. The maximum biomechanical pull-out strength was not statistically different between experimental and control groups at 2 weeks, but significantly higher in the experimental group at 4 and 8 weeks after surgery (P < 0.05).

CONCLUSION

The present study indicated that the transplanted BMSCs could promote tendon-to-bone tunnel healing at 4-8 weeks postoperatively. Dil- and SPIO-labeled transplanted BMSCs distributed at the tendon-bone interface and might play a role in promoting tendon-to-bone tunnel healing, which may be translated into practical cytotherapy for patients those who need earlier rehabilitation for ligament reconstruction surgery in clinic.

Tibial fixation in anterior cruciate ligament reconstruction: a prospective randomized study comparing metal interference screw and staples with a centrally placed polyethylene screw and sheath

BACKGROUND

The use of hamstring tendons for anterior cruciate ligament reconstruction has increased in popularity over recent years. However, concerns with the stability of graft fixation on the tibial side remain. Centrally placed interference screw/sheath implants have demonstrated promising results in biomechanical studies.

HYPOTHESIS

Centrally placed, polyethylene screw and sheath implants will provide clinically equivalent fixation to the standard metal interference screw and supplemental staple fixation.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 113 consecutive patients undergoing isolated, unilateral, primary anterior cruciate ligament reconstruction with hamstring autografts were randomized to tibial fixation with metal interference screw and staples (RCI) or with a centrally placed polyethylene screw and sheath implant (INTRAFIX). Prospective assessment of subjective outcomes was performed using Lysholm, Mohtadi, and International Knee Documentation Committee (IKDC) scores.

RESULTS

At minimum 2-year follow-up, there were no significant differences between the 2 groups in terms of instrumented stability testing (KT-1000 arthrometer) or subjective assessment of knee outcomes (IKDC, Lysholm, Mohtadi). Both fixation methods demonstrated a significant, but not different, increase in outcomes scores from preoperative to postoperative evaluation. There were 7 failures (5 INTRAFIX, 2 RCI) caused by reinjury, but no statistically significant differences were observed between the 2 fixation methods.

CONCLUSION

The centrally placed polyethylene screw and sheath provided equivalent clinical outcomes at minimum 2-year follow-up to standard tibial fixation with metal interference screw and staples.

Comparison between hamstring autograft and free tendon Achilles allograft: minimum 2-year follow-up after anterior cruciate ligament reconstruction using EndoButton and Intrafix

PURPOSE

This study is to compare the clinical and radiographic results of anterior cruciate ligament (ACL) reconstruction with four-stranded autogenous hamstring tendon and two-stranded free tendon Achilles allograft fixed with EndoButton in the femoral tunnel and Intrafix in the tibial tunnel.

MATERIALS AND METHODS

106 patients diagnosed with ACL rupture underwent ACL reconstruction. Autogenous hamstring tendon was used in 33 patients (group I) and free tendon Achilles allografts were used in 32 patients (group II). Median age was 23 years old (20-51) in group I and 22 years old (20-55) in group II. Range of motion, Lachman test, Pivot shift test, IKDC score, Lysholm score and side-to-side difference (SSD) were evaluated preoperatively and at the last follow-up. Tegner activity scale was evaluated before injury and at the last follow-up.

RESULTS

The mean follow-up periods were 28.1 months in group I and 31.6 months in group II. Range of motion of the knee was not different from that of the unaffected side in most cases except one flexion deficit in group I and three in group II (n.s.). One in group I and three in group II showed grade two or three laxity on Lachman test at the last follow-up. One in group I and three in group II showed clear positive results on Pivot shift test at the last follow-up. Thirty in group I and 26 in group II were classified to IKDC A or B at the last follow-up (n.s.). Median Lysholm scores were 98 (85-100) in group I and 99 (85-100) in group II at the last follow-up (n.s.). Median Tegner activity scales were 6 (5-9) in group I and 6 (4-9) in group II at the last follow-up (n.s.). The mean SSD at the last follow-up were 1.4 ± 2.0 mm in group I and 1.9 ± 2.4 mm in group II (n.s.).

CONCLUSION

Clinical and radiological outcomes of ACL reconstruction with two-stranded free tendon Achilles allograft were comparable to those of four-stranded autogenous hamstring tendon. This technique is reasonable to accomplish good results without some weaknesses when using allograft with bone block.

LEVEL OF EVIDENCE

Therapeutic randomized controlled prospective study, Level I.

Anterior cruciate ligament reconstruction using quadriceps tendon autograft for adolescents with open physes- a technical note

Background

One major concern in the treatment of ACL lesions in children and adolescents with open physes is the risk of iatrogenic damage to the physes and a possibly resulting growth disturbance.

Purpose

The primary purpose of this article is to describe our technique of a transphyseal ACL reconstruction using quadriceps tendon-bone autograft in children and adolescents with open growth plates. The secondary aim is to report our early results in terms of postoperative growth disturbances which are considered to be a major concern in this challenging group of patients. It was our hypothesis that with our proposed technique no significant growth disturbances would occur.

Methods

From January 1997 to December 2007 49 consecutive children and adolescents with open growth plates were treated for a torn ACL using the aforementioned surgical technique. The patients (28 males and 21 females) with a median age at surgery of 13 (range 8-15) years were retrospectively evaluated. Outcome measures were follow-up radiographs (weight-bearing long leg radiographs of the injured and uninjured knee, anteroposterior and lateral views, a tangential view of the patella and a tunnel view of the injured knee) and follow-up notes (6 weeks, 3, 6, 12 months and until closing of physes) for occurrence of any tibial and/or femoral growth changes.

Results: All of the 49 patients had a sufficient clinical and radiological follow-up (minimum 5 years, rate 100%). 48 cases did not show any clinical and radiological growth disturbance. One case of growth disturbance in a 10.5 years old girl was observed. She developed a progressive valgus-flexion deformity which was attributed to a malplacement of the autograft bone block within the femoral posterolateral epiphyseal plate leading to an early localized growth stop. None of the patients were reoperated due to ACL graft failure. Five of the patients underwent revision ACL surgery due to another adequate sports trauma after the growth-stop. The tibial fixation screw had to be removed under local anaesthesia in 10 patients.

Conclusions

The described ACL reconstruction technique represents a promising alternative to previously described procedures in the treatment of children and adolescents with open growth plates. Using quadriceps tendon future graft availability is not compromised, as the most frequently used autograft-source, ipsilateral hamstring tendons, remains untouched.

Gravity-assisted pivot-shift test can predict the function of the reconstructed anterior cruciate ligament

PURPOSE

The gravity-assisted pivot-shift (GAPS) test is a newly advocated test for anterior cruciate ligament (ACL) injury. We retrospectively investigated the relationships between the result of preoperative GAPS test and the function of the reconstructed ACL using autogenous hamstring tendon grafts.

METHODS

Seventy-eight patients with unilateral ACL injury and a minimum of 1-year follow-up were enrolled in this study. According to the result of preoperative GAPS test, they were divided into two groups, i.e., positive test group (Group P) and negative test group (Group N). At the time of follow-up, the operated knee was examined manually and using KT-1000 arthrometer. According to these results, the function of the reconstructed ACL was classified.

RESULTS

The proportion of the knees with a negative abnormal laxity test was less in Group P than Group N with the significant difference in Lachman test (P = 0.0029) and N-test (P = 0.0081). The proportion of the cases having greater than 3 mm of the side-to-side difference in anterior knee laxity using KT-1000 arthrometer was greater in Group P, in spite of no statistically significant difference. Regarding the classification of the function of the reconstructed ACL, Group P was worse than Group N (P = 0.0187), and all 4 knees classified as failed belonged to Group P.

CONCLUSION

The knees with a preoperative positive GAPS test showed worse postoperative function of the reconstructed ACL than those with a negative test. Preoperative positive GAPS test is considered to be a predisposing factor to poor functional outcome after ACL reconstruction. It is possible that the use of hamstring tendons as a graft source should be avoided for the ACL-injured patients with a positive GAPS test.