Patellar versus hamstring tendons in anterior cruciate ligament reconstruction: A meta-analysis

Joint laxity and isokinetic thigh muscle strength characteristics after anterior cruciate ligament reconstruction: bone patellar tendon bone versus quadrupled hamstring autografts

OBJECTIVES

To analyze ligamentous stability and isokinetic strength of knee extensor and flexor muscles after anterior cruciate ligament reconstruction using 2 different autografts with identical fixation.

DESIGN

This study implements a comparative case series design.

SETTING

Schulthess Clinic, Switzerland.

PATIENTS

A total of 153 consecutive patients (n = 87 bone-patellar tendon-bone [BPTB]/66 quadruple semitendinosus/gracilis tendons [QSGT] patients) who underwent BPTB and QSGT surgery were functionally assessed.

INTERVENTION

All patients were functionally assessed (knee extension/flexion isokinetic strength and knee joint laxity) at a mean follow-up time of 11 months.

MAIN OUTCOME MEASUREMENTS

Laxity was measured utilizing the Kneelax arthrometer, whereas isokinetic strength of the knee extensor/flexor muscle groups was measured using the Biodex Multi Joint System 2 (180 degrees/s and 300 degrees/s).

RESULTS

The QSGT group had significantly greater knee joint laxity when compared with the BPTB group (P < 0.001). Furthermore, females in the QSGT group demonstrated the greatest knee joint laxity overall (P < 0.001). Additionally, a significant flexor torque deficiency was demonstrated in the QSGT group (P < 0.001); however, no differences in extensor torque were observed.

CONCLUSIONS

The use of a BPTB autograft achieved better knee joint stability as well as greater knee flexor torque than the QSGT autograft. Both grafts exhibited a similar knee extensor torque deficit, indicating that only quadriceps strength is not graft-dependent.

A meta-analysis of stability after anterior cruciate ligament reconstruction as a function of hamstring versus patellar tendon graft and fixation type

PURPOSE

Four-strand hamstring graft (4HS) is stronger than 10-mm bone-patellar tendon-bone graft (BPTB) and has equal tunnel pullout strength, but is believed by some to produce lower rates of stability after anterior cruciate ligament reconstruction (ACLR). Our purpose was to test the hypothesis that 4HS ACLR with modern fixation would produce equal or greater stability than BPTB ACLR.

TYPE OF STUDY

Meta-analysis.

METHODS

A computer search was used to find all published reports of ACLR series using HS and/or BPTB. Inclusion criteria were minimum 24-month follow-up, stratified presentation of arthrometric stability data, and at least 30-lb arthrometric testing force. Twenty-four 4HS, 8 2-strand hamstring (2HS), and 32 BPTB series met these criteria and were subdivided into groups according to fixation type. We used the International Knee Documentation Committee classification of a side-to-side instrumented Lachman test difference of < or = 2 mm as normal stability, and > 5 mm difference as abnormal stability. Series with at least 80% normal and at most 3% abnormal stability were designated as high-stability. Meta-analytic methods were used to determine group level differences.

RESULTS

Total 4HS had a higher normal stability rate than total BPTB: 77% versus 66%, P < .001; and lower abnormal stability: 4.4% versus 5.9%, P = .029. The 4HS ACLR using the EndoButton (Smith & Nephew Endoscopy, Andover, MA) and second-generation tibial fixation (EB2-4HS) had higher normal stability (80%) and lower abnormal stability (1.7%) than all other subgroups, including BPTB with 2 interference screws (70% normal, 5.0% abnormal) P < .001; 84% of the series in the EB2-4HS group were high-stability series. No more than 33% of the series from any other group were high-stability.

CONCLUSIONS

The recent literature would suggest that 4HS ACLR produces higher stability rates than BPTB, that 4HS stability rates are fixation dependent, that aperture fixation offers no stability advantage, and that EndoButton with second-generation tibial fixation produces consistently high stability rates.

LEVEL OF EVIDENCE

Level IV.

Arthroscopic double-bundle anterior cruciate ligament reconstruction: an anatomic approach

The anterior cruciate ligament consists of 2 functional bundles, the anteromedial and the posterolateral bundle. Anterior cruciate ligament reconstruction has traditionally focused on recreating the anteromedial bundle, while the reconstruction of the posteromedial bundle has not routinely been addressed. The authors, from 2 academic centers, present a technique of arthroscopic anterior cruciate ligament reconstruction that restores both the anteromedial and the posterolateral bundle using either semitendinosus and gracilis autografts or tibialis anterior allografts. This technique represents a novel approach to restore the anteromedial and the posterolateral bundle at their anatomic insertion sites on both the tibia and the femur through separate bone tunnels. We believe that our double-bundle anatomic anterior cruciate ligament reconstruction closely reapproximates the native insertion sites of the anterior cruciate ligament on the tibia and the femur while more closely recreating the biomechanical function of the native ligament.

Treatment of anterior cruciate ligament injuries, part I

Anterior cruciate ligament injuries are common among athletes. Although the true natural history remains unclear, anterior cruciate ligament injuries are functionally disabling; they predispose the knee to subsequent injuries and the early onset of osteoarthritis. This article, the first in a 2-part series, was initiated with the use of the PubMed database and a comprehensive search of articles that appeared between January 1994 to the present, using the keywords anterior cruciate ligament. A total of 3810 citations were identified and reviewed to determine the current state of knowledge about the treatment of these injuries. Articles pertaining to the biomechanical behavior of the anterior cruciate ligament, the prevalence of anterior cruciate ligament injury, the natural history of the anterior cruciate ligament-deficient knee, injuries associated with anterior cruciate ligament disruption, risk factors for anterior cruciate ligament injury, indications for treatment of anterior cruciate ligament injuries, and nonoperative and operative treatments were obtained, reviewed, and served as the basis for part I. Part II, to be presented in another issue of this journal, includes technical aspects of anterior cruciate ligament surgery, bone tunnel widening, graft healing, rehabilitation after reconstruction, and the effect of sex, age, and activity level on the outcome of surgery. Our approach was to build on prior reviews and to provide an overview of the literature for each of the before-mentioned areas of study by summarizing the highest level of scientific evidence available. For the areas that required a descriptive approach to research, we focused on the prospective studies that were available; for the areas that required an experimental approach, we focused on the prospective, randomized controlled trials and, when necessary, the highest level of evidence available. We were surprised to learn that considerable advances have been made during the past decade regarding the treatment of this devastating injury.

The effect of screw taper on interference fit during load to failure at the soft tissue/bone interface

The effect of screw geometry on the pullout strength of an anterior cruciate ligament reconstruction is well documented. The effect of a truly tapered screw has not been previously investigated. Thirty bovine knees in right and left knee pairs were collected. Superficial digital flexors from the hind legs of sheep were harvested to form a quadruple tendon graft. For each knee pair, one tendon graft was fixed using a tapered screw (n=15) and the other with a non-tapered screw (n=15). Interference screws were manufactured from stainless steel, and apart from the tapered or non-tapered profile were identical. The screws were inserted into a tibial tunnel already containing the tendon graft. The interference fit was tested by extensile load to failure tests. The insertion torque of the screws and first sign of load to failure (by pullout) of the interference fit were recorded. Results were analysed using paired t-tests. The results indicated that tapered screws have significantly higher resistance to interference failure (p=0.007) and insertion torque (p<0.001) than non-tapered screws. The improved biomechanical performance of tapered screws demonstrated in this study may translate into superior clinical results, particularly at the tibial attachment of hamstring anterior cruciate ligament reconstruction, and also of hamstring fixation to the medial femoral condyle for patella instability.

Hamstring tendon versus patellar tendon anterior cruciate ligament reconstruction using biodegradable interference fit fixation: a prospective matched-group analysis

BACKGROUND

There are still controversies about graft selection for primary anterior cruciate ligament reconstruction, especially with respect to knee stability and functional outcome.

HYPOTHESIS

Biodegradable interference screw fixation of hamstring tendon grafts provides clinical results similar to those achieved with identical fixation of bone-patellar tendon-bone grafts.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

In 1996 and 1997, primary isolated anterior cruciate ligament reconstruction using a bone-patellar tendon-bone autograft was performed in 72 patients. Since 1998, hamstring tendons were used as routine grafts. Matched patients with a hamstring tendon graft were selected from a database (n = 284). All patients were followed prospectively for a minimum of 2 years with KT-1000 arthrometer testing, International Knee Documentation Committee score, and Lysholm score.

RESULTS

In the bone-patellar tendon-bone group, 9 patients were excluded because of bilateral rupture of the anterior cruciate ligament, 3 patients (4.2%) had a graft rupture, and 4 patients were lost to follow-up (follow-up rate, 92.1%), leaving 56 patients for a matched-group analysis. In the hamstring tendon database, the graft rupture rate was 5.6% (P = .698). The Lysholm score was 89.7 in the patellar tendon group and 94 in the hamstring tendon group (P = .003). The KT-1000 arthrometer side-to-side difference was 2.6 mm for the patellar tendon group and 2.1 mm for the hamstring tendon group (P = .041). There were significantly less positive pivot-shift test results in the hamstring tendon group (P = .005), and hamstring tendon patients showed lower thigh atrophy (P = .024) and patellofemoral crepitus (P = .003). Overall International Knee Documentation Committee scores were better (P = .001) in the hamstring tendon group (hamstring tendon: 34 x A, 21 x B, 0 x C, 0 x D; bone-patellar tendon-bone: 17 x A, 32 x B, 6 x C, 0 x D).

CONCLUSIONS

In this comparison of anterior cruciate ligament reconstruction with bone-patellar tendon-bone and anatomical hamstring tendon grafts, the hamstring tendon graft was superior in knee stability and function. These findings are partially contrary to previous studies and might be attributable to the use of an anatomical joint line fixation for hamstring tendon grafts. Thus, hamstring tendons are the authors' primary graft choice for anterior cruciate ligament reconstruction, even in high-level athletes.

The "ligamentization" process in human anterior cruciate ligament reconstruction with autogenous patellar and hamstring tendons: a biochemical study

BACKGROUND

There is little information documenting whether the phenomenon of "ligamentization," as proposed by Amiel, occurs in the human anterior cruciate ligament after clinically effective reconstruction. To clarify this point, we analyzed biochemical differences between the native anterior cruciate ligament; the patellar, semitendinosus, and gracilis tendons; and anterior cruciate ligaments reconstructed with autografts.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Fifty patients who underwent arthroscopically assisted anterior cruciate ligament reconstruction using either semitendinosus and gracilis tendon or bone-patellar tendon-bone autografts were selected for the study. Samples of grafted tissue were collected during arthroscopy and quantitatively analyzed for collagen content and the amount of reducible and nonreducible crosslinks at 4 to 6 postoperative months in patients with semitendinosus and gracilis tendon grafts and at 11 to 13 months in all patients with semitendinosus and gracilis tendon or bone-patellar tendon-bone grafts.

RESULTS

The total collagen content and nonreducible/reducible crosslink ratios increased significantly during the postoperative period (P < .05). The dihydroxylysinonorleucine/hydroxylysinonorleucine ratio was 3.11 +/- 0.56 in the native anterior cruciate ligament, 1.21 +/- 0.47 in the patellar tendon, and 3.59 +/- 1.58 in the anterior cruciate ligaments reconstructed with bone-patellar tendon-bone autografts 1 year after surgery. The dihydroxylysinonorleucine/hydroxylysinonorleucine ratio in both semitendinosus and gracilis tendons was less than 1.0. However, in anterior cruciate ligaments reconstructed with semitendinosus and gracilis tendon autografts, it was 2.34 +/- 0.98 at 4 to 6 months and 3.43 +/- 1.61 at 11 to 13 months after the operation.

CONCLUSIONS

After anterior cruciate ligament reconstruction with autografts, biochemical characteristics of the graft resembled those of the native anterior cruciate ligament. These findings suggest that, regarding the amount of collagen crosslinks and their architecture, the phenomenon of ligamentization occurs in the successfully reconstructed human anterior cruciate ligament within 1 year after operation.

Reconstruction of the anterior cruciate ligament: meta-analysis of patellar tendon versus hamstring tendon autograft

PURPOSE

No graft tissue has consistently shown superiority over others for reconstruction of the anterior cruciate ligament (ACL). Bone-patellar tendon-bone (BPTB) and doubled hamstring tendon (semitendinosus and gracilis) (HT) are the most commonly used autologous grafts. We performed a meta-analysis to compare the effectiveness of ACL reconstruction using either BPTB or HT grafts.

TYPE OF STUDY

Systematic review and meta-analysis.

METHODS

We searched the MEDLINE database (1966 to April 2003) for English-language randomized or prospective studies comparing BPTB and 3- or 4-strand HT grafts used for ACL reconstruction. For inclusion, studies were required to follow identical rehabilitation protocols within each study, and provide subjective or objective outcome data after a minimum average 2-year follow-up. Comparison data between BPTB and HT for each identified outcome measure were combined using a random-effects model meta-analysis.

RESULTS

Eleven reports fulfilled the criteria for inclusion. Outcomes favoring BPTB were found in the following outcome measures: normal Lachman examination (relative risk [RR], 0.91; 95% confidence interval [CI], 0.83-0.99; P = .025), normal pivot-shift (RR, 0.94; 95% CI, 0.88-1.0; P = .067), KT-1000 manual-maximum side-to-side difference of < or = 3 mm (RR, 0.75; 95% CI, 0.55-1.01; P = .057), and fewer reconstructions resulting in flexion loss > 5 degrees (RR, 1.41; 95% CI, 1.01-1.96; P = .04). Intermediate level laxity was more common with the HT graft, as shown by higher rates of abnormal Lachman > 0 (RR, 1.22; 95% CI, 0.99-1.5; P = .06), pivot-shift > 0 (RR, 1.3; 95% CI, 0.96-1.75; P = .09), and KT-1000 manual-maximum side-to-side differences > 3 mm (RR, 1.64; 95% CI, 1.13-2.39; P = .01). Outcome measures that favored HT were absence of patellofemoral crepitance (RR, 1.08; 95% CI, 1.01-1.15; P = .03), fewer results with extension loss > 5 degrees (RR, 0.56; 95% CI, 0.3-1.03; P = .06), and kneeling pain. The incidence of instability, as defined by Lachman grade 2, pivot-shift grade 2, or KT-1000 manual-maximum side-to-side difference > 5 mm, was not significantly different between the 2 grafts. All other outcome measures were not significantly different.

CONCLUSIONS

The data presented in this meta-analysis show that the incidence of instability is not significantly different between the BPTB and HT grafts. However, BPTB was more likely to result in reconstructions with normal Lachman, normal pivot-shift, KT-1000 manual-maximum side-to-side difference < 3 mm, and fewer results with significant flexion loss. In contrast, HT grafts had a reduced incidence of patellofemoral crepitance, kneeling pain, and extension loss. The choice of graft by the patient and surgeon must be individualized, and the results of this meta-analysis can aid in the decision by clarifying the risks and benefits of each surgical approach.

LEVEL OF EVIDENCE

Level I.

Patellar tendon or four-strand hamstring? A systematic review of autografts for anterior cruciate ligament reconstruction

The choice of graft for anterior cruciate ligament reconstruction remains controversial. A systematic review was performed to compare bone-patella tendon-bone and four-strand hamstring grafts. Medline (1966 onwards), EMBASE (1980 onwards) and the Cochrane database were searched retrieving 6312 possible articles, but only 6 studies fulfilled all the inclusion criteria. To be included, the study had to be prospective, randomised or quasi-randomised, comparing 4SHS and central third BPTB autografts, inserted using an arthroscopically assisted technique and have a minimum 2-year follow-up for all patients. These studies recruited 526 patients, and 475 were followed for at least 2 years with 235 patients receiving a bone-patella tendon-bone graft and 240 receiving a four-strand hamstring graft. Overall, there was a greater chance of extension loss (p=0.007) and a trend towards increased patellofemoral joint pain (p=0.09) with a patella tendon graft. With a four-strand hamstring graft, there is a greater loss of hamstring power (p=0.008) and a trend towards an increased chance of a pivot shift >1 (p=0.12). There was no difference between the two groups in terms of Lachman testing, chance of returning to the same level of sport, clinical knee scores, graft ruptures or other complications.

Graft selection in anterior cruciate ligament reconstruction

The ideal graft for use in anterior cruciate ligament reconstruction should have structural and biomechanical properties similar to those of the native ligament, permit secure fixation and rapid biologic incorporation, and limit donor site morbidity. Many options have been clinically successful, but the ideal graft remains controversial. Graft choice depends on surgeon experience and preference, tissue availability, patient activity level, comorbidities, prior surgery, and patient preference. Patellar tendon autograft, the most widely used graft source, appears to be associated with an increased incidence of anterior knee pain compared with hamstring autograft. Use of hamstring autograft is increasing. Quadriceps tendon autograft is less popular but has shown excellent clinical results with low morbidity. Improved sterilization techniques have led to increased safety and availability of allograft, although allografts have a slower rate of incorporation than do most types of autograft. No graft has clearly been shown to provide a faster return to play. However, in general, patellar tendon autografts are preferable for high-performance athletes, and hamstring autografts and allografts have some relative advantages for lower-demand individuals. No current indications exist for synthetic ligaments.

Gait patterns after anterior cruciate ligament reconstruction are related to graft type

BACKGROUND

Although there is a tendency toward gait normalization after anterior cruciate ligament reconstruction, altered moments about the knee flexion-extension axis have been reported. It is possible that these gait alterations relate to donor site morbidity associated with the graft harvest.

HYPOTHESIS

There is a relationship between graft type and external knee moments during walking.

STUDY DESIGN

Controlled laboratory study.

METHODS

Three groups were compared: 17 patellar tendon anterior cruciate ligament reconstruction patients (mean, 11 months after surgery), 17 hamstring tendon anterior cruciate ligament reconstruction patients (mean, 9.3 months after surgery), and 17 matched controls. A 3-dimensional motion analysis and force plate system was used to determine sagittal plane kinematics and kinetics of the lower limb during comfortable-speed walking.

RESULTS

There were significant differences in the moments about the knee that related to graft type. The external knee flexion moment at midstance was significantly smaller than that in the control knees in 65% of patients in the patellar tendon group and 29% of patients in the hamstring tendon group. In contrast, the external knee extension moment at terminal stance was significantly smaller than that in the control knees in 53% of subjects in the hamstring tendon group and 23% of subjects in the patellar tendon group.

CONCLUSIONS

There are graft-specific differences in knee biomechanics after anterior cruciate ligament reconstruction that appear to relate to the donor site.

CLINICAL RELEVANCE

Considerable debate continues as to whether the patellar tendon or the hamstring tendon graft is preferable for anterior cruciate ligament reconstruction. It is therefore clinically relevant to understand the biomechanical differences in knee function associated with both graft types.

Donor site morbidity and return to the preinjury activity level after anterior cruciate ligament reconstruction using ipsilateral and contralateral patellar tendon autograft: a retrospective, nonrandomized study

AIM

To compare the donor site morbidity after anterior cruciate ligament reconstruction using ipsilateral and contralateral bone-patellar tendon autograft.

STUDY DESIGN

Cohort study; Level of evidence, 2 PATIENTS AND METHOD: Between 1997 and 1999, 100 patients underwent anterior cruciate ligament reconstruction with autologous bone-patellar tendon graft. The reconstructions were performed using ipsilateral bone-patellar tendon graft in 52 patients (group Ip) and contralateral bone-patellar tendon graft in 48 patients (group Co). Group Co consisted of 2 subgroups: group CoD consisted of the donor knees (n=48) and group Co-ACL consisted of the anterior cruciate ligament-reconstructed knees (n=48). Mean follow-up was 39.2 months. Donor site morbidity was evaluated with a questionnaire, computerized historical data, KT-2000 arthrometer measurements, the Cincinnati score, and the Tegner score.

RESULTS

KT-2000 arthrometer evaluation showed a mean side-to-side difference of 0.6 mm in both groups. There were no significant differences between the 2 groups concerning the Cincinnati and Tegner scores. With regard to local tenderness, a significantly higher rate was found in group Ip (59.6%) and group Co-D (58.3%) compared with group Co-ACL (6.3%). In groups Ip and Co-D, high statistically significant differences were also found according to kneeling pain (69.2% and 70.8%, respectively) and knee-walking pain (76.9% and 70.8%, respectively) compared with group Co-ACL (6.3% and 10.4%, respectively). With regard to numbness, there was no statistical significance between the rates of all 3 groups: group Ip=75%, group Co-D=85.4%, and group Co-ACL=64.6%. There was one rupture of the patellar tendon and one patient with chronic patellar tendinitis, both in the donor knee of group Co-D.

CONCLUSION

The contralateral bone-patellar tendon graft appears to present no advantage over the ipsilateral graft, as all symptoms concerning donor site morbidity are shifted from the injured into the healthy knee, and return to activity is not more rapid.

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

PURPOSE

The aim of this study was to compare the results after arthroscopic anterior cruciate ligament (ACL) reconstruction using central-third, bone-patellar tendon-bone (BPTB group), 3-strand semitendinosus (ST group), or 4-strand semitendinosus/gracilis (ST/G group) autografts.

TYPE OF STUDY

Prospective randomized trial.

METHODS

A randomized series of 134 patients, all with unilateral ACL rupture was included in the study. In all 3 groups, interference screw fixation of the graft was used at both ends and 125 of 134 (93%) of the patients returned for the follow-up examination after 26 months (range, 20 to 43 months). The preoperative assessments in all 3 groups were similar in terms of gender, Tegner activity level, Lysholm score, KT-1000 measurements, 1-leg hop test, and the knee-walking test.

RESULTS

At follow-up, the knee-walking test was significantly worse in the BPTB group than in the ST group (P = .0004) and ST/G group (P < .0001). Furthermore, the knee-walking test was significantly worse at follow-up than preoperatively in the BPTB group (P < .0001). The corresponding findings were not made in the other 2 groups. A significant reduction in knee laxity and an increase in activity level compared with the preoperative assessments were found in all 3 groups, without any significant differences between the groups.

CONCLUSIONS

Two years after ACL reconstruction, the use of ST and ST/G autografts rendered significantly less discomfort during the knee-walking test than the use of BPTB autografts. However, in terms of functional outcome and knee laxity, the groups displayed no significant differences.

LEVEL OF EVIDENCE

Level I.

Anterior cruciate ligament reconstruction autograft choice: bone-tendon-bone versus hamstring: does it really matter? A systematic review

Anterior cruciate ligament graft choice is controversial, with no evidence-based consensus available to guide decision making. The study design was evidence-based medicine systematic review of randomized controlled trials evaluating patellar tendon versus hamstring tendon autografts. A literature review identified 9 randomized controlled trials comparing patellar tendon and hamstring tendon autografts. An evidence-based systematic review was performed. Objective and subjective outcomes of interest included surgical technique, rehabilitation, instrumented laxity, isokinetic strength, patellofemoral pain, return to preinjury activity, and Tegner, Lysholm, Cincinnati, and International Knee Documentation Committee-1991 scores. Additional surgery, graft failure, and complications were reviewed. Slight increased laxity on arthrometer testing was seen in the hamstring population in 3 of 7 studies. Pain with kneeling was greater for the patellar tendon population in 4 of 4 studies. Only 1 of 9 studies showed increased anterior knee pain in the patellar tendon group. Frequency of additional surgery seemed to be related to the fixation method and not graft type. No study reported a significant difference in graft failure between patellar tendon and hamstring tendon autografts. Objective differences (range of motion, isokinetic strength, arthrometer testing) were not detected between groups in the majority of studies, suggesting that their sensitivity to detect clinical outcomes may be limited. Increased kneeling pain in the patellar tendon group was seen consistently in the studies evaluated. Subjective differences in anterior knee pain or return-to-activity level were not consistently observed in these studies. With numbers available, failure rates were not significantly different between groups. These findings suggest that graft type may not be the primary determinant for successful outcomes after anterior cruciate ligament surgery.

Anterior cruciate ligament reconstruction: bone-patellar tendon-bone compared with double semitendinosus and gracilis tendon grafts. A prospective, randomized clinical trial

BACKGROUND

The choice of graft for anterior cruciate ligament reconstruction is a matter of debate, with patellar and hamstring tendons being the two most popular autologous graft options. The objective of this study was to determine in a prospective, randomized clinical trial whether two grafts (bone-patellar tendon-bone or doubled hamstring tendons) fixed with modern devices affect the two-year minimum clinical and radiographic outcomes of anterior cruciate ligament reconstruction.

METHODS

One hundred and twenty patients with a chronic unilateral rupture of the anterior cruciate ligament underwent arthroscopically assisted reconstruction with use of either autologous bone-patellar tendon-bone or doubled hamstring tendon grafts, in a strictly alternating manner. Both groups were comparable with regard to demographic data, preoperative activity level, mechanism of injury, interval between the injury and the operation, and the amount of knee laxity present preoperatively. The same well-proven surgical technique and aggressive controlled rehabilitation was used. An independent observer, who was blinded with regard to the involved leg and the type of graft, performed the outcome assessment with use of a visual analog scale, the new International Knee Documentation Committee form, the Knee Injury and Osteoarthritis Outcome Score, the Functional Knee Score for Anterior Knee Pain, and an arthrometric and an isokinetic dynamometric evaluation. Radiographs were also made.

RESULTS

At the two-year follow-up evaluation, no differences were found in terms of the visual analog score, the Knee Injury and Osteoarthritis Outcome Score, the new International Knee Documentation Committee subjective and objective evaluation scores, the KT-1000 side-to-side laxity measurements, the Functional Knee Score for Anterior Knee Pain, muscle strength recovery, or return to sports activities. In the bone-patellar tendon-bone group, we found a higher prevalence of postoperative kneeling discomfort (p < 0.01) and an increased area of decreased skin sensitivity (p < 0.001). In the hamstring tendon group, we recorded a higher prevalence of femoral tunnel widening (p < 0.01). In this group, a correlation was also found between medial meniscectomy and an increased prevalence of pivot-shift glide (p = 0.035).

CONCLUSIONS

We believe that, with use of accurate and proven surgical and rehabilitation techniques, both grafts are an equivalent option for anterior cruciate ligament reconstruction.

A biomechanical evaluation of transcondylar femoral fixation of anterior cruciate ligament grafts

BACKGROUND

Interference screw fixation of the graft in anterior cruciate ligament reconstruction is considered the gold standard, but limited clinical experience suggests that transcondylar fixation is equally effective.

PURPOSE

To compare transcondylar and interference screw fixation.

STUDY DESIGN

Ex vivo biomechanical study.

METHODS

Twenty pairs of unembalmed knees underwent anterior cruciate ligament reconstruction with patellar tendon autografts. In 1 knee of each pair, the bone plug was stabilized in the femoral tunnel with standard interference screws; in the other knee, transcondylar screws were used. Testing to failure occurred immediately or after 1000 cycles of sinusoidal loading (30 to 150 N) (20 paired reconstructions each). Fixation stiffness, strength, graft creep, displacement amplitude, and change in amplitude were measured and compared (repeated measures anaylsis of variance with Tukey test; P <.05).

RESULTS

There was no significant difference in acute strength, maximum load within 3 mm, or stiffness between transcondylar fixation (410 +/- 164 N, 183 +/- 93 N, and 49.6 +/- 28 N/mm, respectively) and interference fixation (497 +/- 216 N, 206 +/- 115 N, and 61 +/- 37.8 N/mm, respectively). Similarly, there was no significant difference in cyclic strength, maximum load within 3 mm, or stiffness between transcondylar fixation (496 +/- 214 N, 357 +/- 82.9 N, and 110 +/- 27.4 N/mm, respectively) and interference fixation (552 +/- 233 N, 357 +/- 76.2 N, and 112 +/- 26.8 N/mm, respectively). Predominant modes of failure were bone plug pullout (transcondylar fixation) and tendon failure or bone plug fracture (interference fixation).

CONCLUSIONS

Transcondylar screw fixation of the patellar tendon autograft into the femoral tunnel performed mechanically as well as interference screw fixation.

CLINICAL RELEVANCE

The results suggest that transcondylar and interference screws provide similar fixation for anterior cruciate ligament reconstruction.

Anterior cruciate ligament reconstruction using cryopreserved allografts

Primary ACL reconstruction historically has been done using autograft tissues whereas allografts have been limited to revision cases and patients who are older or with lower physical demands because some animal studies suggested a slower biologic incorporation rate. The purpose of the current study was to evaluate the effectiveness of the cryopreserved Achilles tendon allograft in primary ACL reconstruction in a consecutive series of athletes. Fifty consecutive patients with a strenuous or moderate preinjury activity level, as defined by the International Knee Documentation Committee (IKDC), had ACL reconstruction using cryopreserved Achilles tendon allografts secured with bioabsorbable interference screws. Five patients were professional athletes. The average age of the patients was 36 years (range, 17-50 years). A 3- to 5-year followup study was done in all of the patients using the IKDC form. Tunnel widening was measured in the lateral radiographs at the widest level. The overall outcome was normal or nearly normal in 94% of the patients. No failures were reported in this series. Forty-six patients (92%) returned to their same preinjury sport activity level. The average KT-1000 side-to-side difference was 2.3 mm. Average tibial tunnel widening was 2.7 mm (range, 0-6 mm); no significant correlation was observed between increased tunnel size and a fair or poor clinical outcome. This experience shows that favorable results can be obtained with cryopreserved Achilles tendon allografts in athletes in whom avoiding donor site morbidity may be an issue in terms of a prompt return to sport.

A new method to determine graft angles after knee ligament reconstruction

In posterior cruciate ligament (PCL) reconstruction, the acute angle of the graft at the tibial tunnel ('the killer curve') has been implicated as a cause of graft failure. Similar acute angles also occur at the entrance to the femoral tunnel. We describe a method to determine the true graft angle, based on measurements taken from two orthogonal radiographs in a cadaveric model, analysed using three-dimensional geometry. The true angles for the tibial and femoral tunnels are presented for a variety of tunnel positions. The effect on these angles of knee flexion and extension is analysed. Resultant graft-tunnel forces at a constant ligament tension are described. Based on these results, drilling the femoral tunnel from outside-in and lateral placement of the tibial tunnel are theoretically advantageous.

Patellar tendon versus quadrupled bone-semitendinosus anterior cruciate ligament reconstruction: a prospective clinical investigation in athletes

PURPOSE

Patellar tendon and hamstrings are both used in anterior cruciate ligament (ACL) reconstruction, and comparisons have been reported with different results. The purpose of this clinical study was to compare the results of ACL reconstruction in athletes with 2 different graft types, both using bone-to-bone healing: bone-patellar tendon-bone graft and a quadrupled bone-semitendinosus graft.

TYPE OF STUDY

Outcomes study.

METHODS

From 1994 to 1997, 2 groups of 40 athletes who underwent ACL replacement with patellar tendon and quadrupled bone-semitendinosus grafts were prospectively evaluated. Preinjury activity level, age, and gender were comparable in both groups. All patients were operated on by the same surgeon within 5 months from injury and underwent group-specific rehabilitation programs. An independent examiner performed the final evaluations at 36 months. Review included clinical examination, radiographs, computed analysis, isokinetic and functional strength tests, and subjective and objective evaluation with standard knee scores. Additional procedures were recorded. Statistical analysis was performed with both parametric and nonparametric tests.

RESULTS

Average surgical time was longer with the semitendinosus graft, and postoperative pain was higher in the patellar tendon group. Standard knee evaluation scores and subjective assessment revealed no significant differences. Isokinetic testing of flexion-extension and internal-external rotation showed lower quadriceps strength and a mild deficit of external rotation in the patellar tendon group and slightly lower flexor strength in the semitendinosus group at 12 months. Computerized laxity analysis showed no difference between the 2 groups with 90% of patients having less than 3 mm side-to-side difference, with a gender difference in the semitendinosus group. Kneeling pain was higher in patellar tendon group.

CONCLUSIONS

The bone-patellar tendon-bone and quadrupled bone-semitendinosus autograft provide excellent grafts for ACL reconstruction. Both techniques are comparable regarding final stability, but in patients with extensor mechanism problems or those who engage in sports with a high incidence of patellar tendonitis, the semitendinosus graft should be considered.

A randomized comparison of patellar tendon and hamstring tendon anterior cruciate ligament reconstruction

BACKGROUND

Patellar and hamstring tendon autografts are the most frequently used graft types for anterior cruciate ligament reconstruction, but few direct comparisons of outcomes have been published.

HYPOTHESIS

There is no difference in outcome between the two types of reconstruction.

STUDY DESIGN

Prospective randomized clinical trial.

METHODS

After isolated anterior cruciate ligament rupture, 65 patients were randomized to receive either a patellar tendon or a four-strand hamstring tendon graft reconstruction, and results were reviewed at 4, 8, 12, 24, and 36 months.

RESULTS

Pain on kneeling was more common and extension deficits were greater in the patellar tendon group. There were greater quadriceps peak torque deficits in the patellar tendon group at 4 and 8 months but not thereafter. In the hamstring tendon group, active flexion deficits were greater from 8 to 24 months, and KT-1000 arthrometer side-to-side differences in anterior knee laxity at 134 N were greater. Cincinnati knee scores, International Knee Documentation Committee ratings, and rates of return to preinjury activity levels were not significantly different between the two groups.

CONCLUSIONS

Both grafts resulted in satisfactory functional outcomes but with increased morbidity in the patellar tendon group and increased knee laxity and radiographic femoral tunnel widening in the hamstring tendon group.

Clinical outcome of anterior cruciate ligament reconstruction with quadrupled hamstring tendon graft and bioabsorbable interference screw fixation

BACKGROUND

To date, there has been no publication of clinical follow-up data on patients who have undergone quadrupled hamstring tendon autograft anterior cruciate ligament reconstruction with bioabsorbable screw fixation.

PURPOSE

To report the results of quadrupled hamstring tendon autograft anterior cruciate ligament reconstruction with bioabsorbable interference screw fixation.

STUDY DESIGN

Retrospective review.

METHODS

Sixty-five patients (66 knees) were retrospectively identified by chart review as having undergone quadrupled hamstring tendon autograft anterior cruciate ligament reconstruction with bioabsorbable interference screw fixation with a minimum 2-year follow-up.

RESULTS

Data were collected on 48 knees in 47 patients (73%) at an average 30.2 months (range, 24 to 43) after surgery. Thirty-six patients (37 knees) returned for clinical evaluation (56% return) and subjective follow-up only was obtained in 11 patients (17%). The mean Lysolm knee score was 91 (range, 45 to 98), with a mean of 97 for the uninvolved knee. The mean Tegner activity score was 5.7 (range, 3 to 7). The KT-1000 arthrometer mean side-to-side difference for manual maximum displacement was 2.03 mm (range, -1 to 8). The mean International Knee Documentation Committee knee score was 83 (range, 47 to 100). Patients who underwent associated partial meniscectomy or meniscal repair had significantly lower International Knee Documentation Committee scores than patients without associated procedures (P < 0.01).

CONCLUSIONS

Quadrupled hamstring tendon autograft anterior cruciate ligament reconstruction with bioabsorbable interference screw fixation is comparable with other methods of anterior cruciate ligament reconstruction in terms of patient satisfaction, knee stability, and function.

ACL Reconstruction With Autografts Weighing Performance Considerations and Postoperative Care

Anterior cruciate ligament (ACL) reconstruction is the treatment of choice for patients who experience episodes of instability and a decreased quality of life after ACL rupture. The bone-patellar tendon-bone and hamstring autografts are the current standards for ACL reconstruction. Primary care physicians, especially sports medicine clinicians, are the first-line providers of nonoperative care for patients who have ACL injuries. Care providers need to know the biologic and biomechanic properties of these grafts, clinical indications for each graft, and rehabilitation considerations to appropriately counsel their patients.

Monopolar thermal treatment of symptomatic anterior cruciate ligament instability

Patients with anterior cruciate ligament instability resulting from incomplete tears or elongation in continuity without ligament detachment historically have been treated conservatively or by graft replacement. The literature is sparse regarding alternative treatments. The current study presents experience using monopolar thermal repair on 28 consecutive knees with partial anterior cruciate ligament tears all symptomatically unstable. All lesions were less than 6 months old (average, 77 days; range, 7-180 days) and with a difference of 6 mm or more (average, 9 mm; range, 6-13 mm) when comparing both knees using KT-1000 evaluation. Incomplete tears of the anterior cruciate ligament were seen at arthroscopic evaluation. The rehabilitation protocol included use of a brace for at least 6 weeks and progressive weightbearing. A 2-year minimum followup (range, 24-35 months) was done in all patients following the International Knee Documentation Committee guidelines. The overall outcome was normal or nearly normal in 96% of the patients. One failure occurred at 8 weeks. Twenty-six knees had a KT-1000 difference between 0 and 2 mm (average, 1.9 mm). Because thermal application causes death to some of the cells directly treated, it should be taken into account in selection and application. Immediately after thermal use, the anterior cruciate ligament, although thicker and tighter, is at first weaker than normal. Rehabilitation and compliance are critical during early ligament healing. This procedure seems to be a reasonable alternative to anterior cruciate ligament grafting in selected patients.

Anterior cruciate ligament reconstruction using semitendinosus and gracilis tendons, bone patellar tendon, or quadriceps tendon-graft with press-fit fixation without hardware. A new and innovative procedure

BONE--PATELLAR TENDON: The "no hardware" technique for ACL reconstruction is a new method that offers many advantages and is straightforward to perform. Its main innovative feature is that it does not require bone-block harvesting from the patella. This reduces donor site morbidity and prevents patellar fractures. The bone tunnels are made using tube harvesters and compaction drilling. This minimizes trauma and obviates the risk of bone necrosis. The articular entrance of the tibial tunnel is completely occupied by the grafts. This prevents a windshield-wiper effect and synovial fluid ingress into the tunnel, and enhances graft incorporation. The fact that no hardware is used with both patellar tendon or hamstring grafts significantly reduces the overall cost of the operation and facilitates revision surgery. The quadriceps tendon is also a very good graft. It is thick and has good biomechanical properties and low donor site morbidity. Its disadvantages are: weakness of quadriceps after the operation, an unsightly scar, and some difficulty in graft harvesting [58]. Also, postoperative MRI is not fraught with the problem of metal artifacts. It is difficult to decide which of the methods currently available for ACL reconstruction is the best because most of them give satisfactory results. In the future, assessments of knee ligament reconstruction techniques should look at long-term stability combined with low complication rates. Ease of revision surgery and low cost should also be taken into consideration, given the large annual volume of knee ligament reconstructions (50,000 in the United States alone) [59]. We believe that our technique addresses most of these issues, and that it constitutes a useful alternative method for ACL reconstruction. SEMITENDINOSUS--GRACILIS: This technique, which was used with 915 patients from June 1998 to February 2002, shows a particularly low rate of postoperative morbidity. The reason is probably to be found in the "waterproofing" of the bone tunnels, which lead to less postoperative bleeding and swelling. No drains were used. Rehabilitation follows the same protocol as used for the reconstruction using patellar tendon grafts (accelerated/functional). As expected, there was no widening of the femoral tunnels and little widening of the tibial tunnels. Interestingly, tibial tunnel enlargement was significantly less in a nonaccelarated rehabilitation group than in the accelerated group [60] without affecting stability. The measured internal torque of the hamstrings, as well as their flexion force, already had returned to normal 12 months postoperatively. In a prospective randomized (unpublished) study comparing this technique with ACL reconstruction with BPT grafts with medial or lateral third with only one bone plug (from the tibial tuberosity, see technique described above), we found no significant difference between both groups in subjective scores, stability, KT-1000 values, Tegner activity score, and IKDC at 1-year follow-up. Only the results of kneeling and knee walking testing were significantly better in the hamstring group [61]. In summary, the advantages of this presented technique are: (1) the knot of the graft is close proximally to the anatomic site of the insertion of the ACL, thus avoiding the Bungee effect.; (2) the press-fit tunnel fixation prevents synovial fluid entering the bone tunnels, windshield-wiper effect, and longitudinal motion within the tunnel; the intensive contact between the bony wall of the tunnel and graft collagen over a long distance without any suture material results in quick and complete graft incorporation; and (3) no fixation material means no hardware problems, facilitates revision surgery, and lowers overall costs.

Arthroscopic anterior cruciate ligament reconstruction: a metaanalysis comparing patellar tendon and hamstring tendon autografts

BACKGROUND

The best choice of graft tissue for use in anterior cruciate ligament reconstruction has been the subject of debate.

HYPOTHESIS

Anterior cruciate ligament reconstruction with patellar tendon autograft leads to greater knee stability than reconstruction with hamstring tendon autograft.

STUDY DESIGN

Metaanalysis.

METHODS

A Medline search identified articles published from January 1966 to May 2000 describing arthroscopic anterior cruciate ligament reconstruction with either patellar tendon or hamstring tendon autograft and with a minimum patient follow-up of 24 months.

RESULTS

There were 1348 patients in the patellar tendon group (21 studies) and 628 patients in the hamstring tendon group (13 studies). The rate of graft failure in the patellar tendon group was significantly lower (1.9% versus 4.9%) and a significantly higher proportion of patients in the patellar tendon group had a side-to-side difference of less than 3 mm on KT-1000 arthrometer testing than in the hamstring tendon group (79% versus 73.8%). There was a higher rate of manipulation under anesthesia or lysis of adhesions (6.3% versus 3.3%) and of anterior knee pain in the patellar tendon group (17.4% versus 11.5%) and a higher incidence of hardware removal in the hamstring tendon group (5.5% versus 3.1%).

CONCLUSIONS

Patellar tendon autografts had a significantly lower rate of graft failure and resulted in better static knee stability and increased patient satisfaction compared with hamstring tendon autografts. However, patellar tendon autograft reconstructions resulted in an increased rate of anterior knee pain.

Anterior cruciate ligament reconstruction utilizing central quadriceps free tendon

CQFT ACL reconstruction yields a stable, highly functional knee with little associated morbidity. Patient satisfaction has been very high, and objective follow-up data collected thus far is very encouraging.

Endoscopic anterior cruciate ligament reconstruction with patella tendon autograft

The patella tendon is the most commonly used graft source for ACL reconstruction because of its biomechanical strength and stiffness, the availability of bone-to-bone healing on either end, and the ability to firmly secure the graft within the tunnels. Consistently good results have been reported in the literature, with expectations to return to all activities at pre-injury levels of performance. We outline our technique for endoscopic ACL reconstruction using a patella tendon autograft. The technique is divided into the critical stages of pre-operative assessment, graft harvest, notch preparation, tunnel placement, graft passage, graft fixation, and rehabilitation. Methods for avoiding pitfalls and overcoming mishaps are described.

Graft selection in anterior cruciate ligament reconstruction

Selecting the appropriate graft for ACL reconstruction depends on numerous factors including surgeon philosophy and experience, tissue availability (affected by anatomical anomalies or prior injury or surgery), and patient activity level and desires. Although the patella tendon autograft has the widest experience in the literature, and is probably the most commonly used graft source, this must be tempered with the higher reported incidences of potential morbidity and pitfalls associated with its use. The hamstring tendons are gaining increasing popularity, mostly due to reduced harvest morbidity and improved soft tissue fixation techniques, and many recent studies in the literature report equal results to BTB ACL reconstruction with respect to functional outcome and patient satisfaction. On the other hand, many of these studies report higher degrees of instrument (KT-100) tested laxity for hamstring reconstruction, and some have reported lower returns to preinjury levels of activity. One question that remains to be addressed is how closely objectively measured laxity tests correlate with subjectively assessed outcomes and ability to return to high levels of competitive sports. Allograft use, which decreased in popularity during the 1990s, appears to be undergoing a resurgence, with better sterilization processes and new graft sources (tibialis tendons), leading to increased availability and improved fixation techniques. The benefits of decreased surgical morbidity and easier rehabilitation must be weighed against the potential for greater failure of biologic incorporation, infection, and possibly slower return to activities. In our practice, for high-demand individuals (those playing cutting, pivoting, or jumping sports and skiing) BTB tends to be the graft of choice. For lower demand or older individuals, hamstring reconstructions will be performed. Allograft tissue will be used in older individuals (generally over 45 years old), those with signs of arthritis (and compelling evidence of instability), or those individuals who understand the pros and cons of allograft use fully and do not want their own tissue used.

Anterior cruciate ligament reconstruction using hamstring tendon grafts

The annual incidence of more than 100,000 anterior cruciate ligament tears has increased with the rise of participation in sports in the general population, especially in females and older participants. Anterior cruciate ligament reconstruction is the standard of care in the young and/or athletically active individuals, based on prospective randomized studies. Replacement tissues to reconstruct the anterior cruciate ligament can be categorized as autograft, allograft, xenograft, and artificial replacements. Historically, xenograft and artificial replacements for the anterior cruciate ligament have failed dismally. As a result, autograft and allograft tissues commonly are used to reconstruct the anterior cruciate ligament. Autograft tissue currently is the most common source for grafts used worldwide. The two most common autograft tissues are the bone-patellar tendon-bone and hamstrings tendons. Controversy exists regarding the advantages and disadvantages of using each of these two tissues. The purpose of the current study was to review the basic science and clinical data regarding the use of the hamstring tendons in anterior cruciate ligament reconstruction.

Current Australian trends in rehabilitation following anterior cruciate ligament reconstruction

This study documented the current approaches to rehabilitation following anterior cruciate ligament (ACL) reconstruction by Australian orthopaedic surgeons. A two-page questionnaire was mailed to the 40 members of the Australian Knee Society to obtain information regarding (1) pre-operative requirements; (2) immediate post-operative requirements; and (3) the timing of the introduction of rehabilitation phases and return to sport following ACL reconstruction. The response rate of practising surgeons was 95%. Twenty-two surgeons (61%) regularly performed both hamstring tendon (HS) and patellar tendon (PT) ACL reconstruction. Eighty-three percent had a standard rehabilitation protocol, and of these, 23% had separate protocols for the two graft types. There were no significant differences between the responses for the two graft types for any question. Approximately three-quarters of surgeons (HS: 75%, PT: 78%) had specific pre-operative requirements. Most surgeons (HS: 96%, PT: 93%) had specific post-operative requirements. Physiotherapy was routinely used by 96% and 93% of surgeons for HS and PT grafts, respectively, commencing at a mean of 2 weeks post-operatively for HS grafts and a mean of 1.5 weeks for PT grafts. Progression through rehabilitation and the timing of return to various levels of sporting activity was similar for both graft types. Few surgeons used strength testing (HS: 25%, PT: 23%) or knee arthrometry (HS: 22%, PT: 17%) prior to return to sport and the use of a brace was rarely recommended for return to sport (HS: 7%, PT: 3%). The results of this survey indicate little variation in the post-operative management of HS and PT ACL reconstruction among members of the Australian Knee Society. Future research should, however, be directed towards the rate of progression through rehabilitation, as this was shown to be more conservative than other recent reports.