4-strand Graft Research Articles

Minimally Invasive Combined Anterior and Anterolateral Stabilization of the Knee Using Hamstring Tendons and Adjustable-Loop Suspensory Fixation Device: Surgical Technique

Despite the numerous techniques described regarding isolated anterior cruciate ligament (ACL) reconstruction, many authors have reported that residual knee rotational instability is not always eliminated. The combination of lateral extra-articular knee tenodesis and ACL reconstruction is an alternative surgical approach with very promising clinical results. The purpose of this article is to describe a reliable and reproducible technique of combined ACL reconstruction and lateral extra-articular knee tenodesis using a continuous looped hamstring tendon autograft. A 4-strand graft inside the joint and a 2-strand graft for the tenodesis are attached to 2 adjustable-loop button suspensory fixation devices.

Five-Strand Hamstring Autograft Versus Quadruple Hamstring Autograft With Graft Diameters 8.0 Millimeters or More in Anterior Cruciate Ligament Reconstruction: Clinical Outcomes With a Minimum 2-Year Follow-Up

To compare the outcomes of 2 groups of patients undergoing anterior cruciate ligament (ACL) reconstruction: the first with a quadrupled semitendinosus gracilis (ST-G) autograft larger than 8mm diameter and the second with a 5-strand ST-G autograft larger than 8mm due to an insufficient diameter graft harvesting. This was a retrospective study with 70 patients divided into 2 groups. Inclusion criteria included ACL ruptures of less than 3months, ST-G ACL reconstructions, and final (4-strand or 5-strand) graft size larger than 8mm. Exclusion criteria included multiligament knee injuries, meniscal or chondral pathology, ACL re-ruptures, inflammatory joint disease, or other procedures in the knee. Group A comprised 33 patients with a quadruple ST-G graft, and group B comprised 37 patients with an insufficient graft diameter (<8mm) in which a 5-strand graft was used. Mean age in group A was 29.7 (range 17-52) years and in group B was 30.6 (range 13-53) years (P= .78). Average follow-up in group A was 32.2 (range 24-48) months and in group B was 30.35 (range 24-48) months (P= .75). Average graft diameter in group A was 8.5mm (range 8-10) and in group B when the graft was measured as quadruple was 7.2mm (range 6.5-7.5) and 9.2mm (range 8-10) when it was converted to 5-strand (P= .00596). Group A had 3 (9%) re-ruptures, and group B had 2 (5.4%) (P= .55). The average postoperative Lysholm score in group A was 93.3 (range 71-100) and in group B was 97.1 (range 80-100) (P= .79). Mean postoperative International Knee Documentation Committee in group A was 91 (range 75.9-100) and in group B was 96.8 (range 82-100) (P= .18). In our study, the 5-strand hamstring autograft in ACL reconstruction was clinically comparable with the quadruple autograft larger than 8mm. The differences in re-rupture and clinical outcomes were not statistically significant between the 2 groups, suggesting that it is a valid option when we have a graft of insufficient diameter. Level III, retrospective comparative study.

Preoperative magnetic resonance imaging evaluation of semitendinosus tendon in anterior cruciate ligament reconstruction: Does this have an effect on graft choice?

Background:Anterior cruciate ligament (ACL) reconstruction with ST autograft is sometimes unsuccessful because of harvested thin graft. Magnetic resonance imaging (MRI) can be a useful tool to evaluate the thickness of the graft. This study is performed to evaluate whether there is any correlation between diameters and cross-sectional area (CSA) of the semitendinosus tendon (ST) on the preoperative magnetic MRI and the diameter of the 4-stranded ST autograft in ACL reconstruction.Materials and Methods:Seventy patients who underwent single-bundle ACL reconstruction with 4-stranded ST for full-thickness ACL ruptures were included in this study. Anteroposterior (AP) and mediolateral (ML) diameters of ST at the levels of the joint line (JL) and femoral physeal line (PL), and also CSA at these levels were measured on T2-weighted fat-suppressed MRI examinations. The data obtained were compared with intraoperatively measured diameters of 4-stranded ST autograft. Correlations between variables were evaluated using Spearman's rho. Receiver operating characteristic and area under the curve statistics were used to evaluate the cut-off value for the correlation between 4-stranded ST graft diameter of 8 mm and CSA (mm2) on MRI.Results:On MRI measurements, no correlation was found between AP diameters at the level of the JL and 4-stranded ST diameter (P = 0.180). However, correlations were found between diameter of 4-stranded ST and ML diameter at the level of JL (P = 0.003) and PL (P = 0.002), AP diameter at the level of the PL (P = 0.009), CSA at the level of the JL (P < 0.001) and at the level of PL (P < 0.001). Correlation between the diameter of 4-stranded ST and CSA at both levels was more significant than that between AP-ML diameters of ST and diameter of autograft. The cut-off value for the 8 mm diameter CSA of 4-stranded ST was 5.9 mm2 at the JL and 8.99 mm2 at the PL.Conclusion:Preoperative MRI evaluation of CSA at the JL of the ST is a reliable parameter to predict graft size. Other graft alternatives should better be considered if the CSA of ST is <5.9 mm2 at the level of the JL.

Comparison of Patellar Tendon and Hamstring Tendon Anterior Cruciate Ligament Reconstruction

Background: Numerous studies have compared patellar tendon (PT) and hamstring tendon (HS) anterior cruciate ligament (ACL) reconstructions in the short to midterm, but fewer long-term results have been published. Hypothesis: There will be no difference in functional outcome between ACL reconstruction performed with PT and HS grafts, but PT grafts will have more donor site morbidity. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Sixty-five patients undergoing ACL reconstruction were randomized to receive either a PT graft or a 4-strand HS graft. Early results were reported at 4, 8, 12, 24, and 36 months. Forty-seven patients (22 of 31 PT and 25 of 34 HS) were reviewed at a mean of 15.3 years. Results: Four graft ruptures (1 PT, 3 HS) and 6 contralateral ACL injuries (4 PT, 2 HS) occurred in the group that was reviewed. There was no statistically significant difference between the groups for any of the variables measured. There was a similar incidence of anterior knee pain and kneeling pain in both groups. The previously observed increased extension deficit in the PT group at 3 years was not present at 15 years, and there was no significant between-group difference in knee laxity. A higher proportion of patients in the PT group were participating in sport on a weekly basis (73% PT, 48% HS; P = .05). There was no difference in the degree of osteoarthritis between the groups. Conclusion: This randomized controlled trial showed that HS and PT ACL reconstructions have comparable results at an average 15-year follow-up. Contrary to the study hypothesis, some of the graft differences seen at earlier review were not present at 15 years, and patients with PT grafts were more active in sport participation. Overall, both graft types provided good long-term subjective and objective outcomes.

The Natural History of Biointerference Screw Cyst and New Bone Formation in Anterior Cruciate Ligament Reconstruction

Background: A variety of fixation devices are available for anterior cruciate ligament reconstruction (ACLR). Bioabsorbable screws allow imaging postoperatively without image artefact, as with magnetic resonance imaging (MRI). There is also the perceived benefit of screw resorption and subsequent host tunnel bone ingrowth. Purpose/Hypothesis: The purpose of this study was to document the natural history of poly L-lactic acid (PLLA) bioabsorbable interference screws. Manufacturers claimed that screws would be resorbed and replaced by new bone within 2 years. The hypothesis was that these screws take considerably longer to achieve this claim. Study Design: Case series; Level of evidence, 4. Methods: Ten consecutive patients undergoing routine ACLR with a PLLA bioabsorbable RCI screw (Arthrex) and a standard 4-strand hamstring graft technique were assessed via MRI and telephone questionnaire at 1, 2, 4, 7, 10, and 16 years postoperatively. Results: At 4-year follow-up, no resorption of the screw or bone formation had occurred. At 7-year follow-up, absorption of 7 screws was complete, cyst formation had occurred in 3 patients, and 5 patients had new bone formation. At 10-year follow-up, all screws were reabsorbed, cyst formation was evident in only 2 cases, and 7 patients had evidence of new bone formation. At 16-year follow-up, cyst formation was only present in 1 patient, and all patients had evidence of new bone formation. All patients had an intact anterior cruciate ligament and had returned to preinjury sporting activity. Conclusion: PLLA bioabsorbable screws take longer to resorb than previously thought by the manufacturers (ie, 2 years). New bone formation is evident in 100% of patients by 16 years. Cyst formation does not occur in all patients with a bioabsorbable screw implant. In the 3 patients demonstrating the presence of a cyst, no associated adverse effects were found with regard to anterior cruciate ligament graft survival or instability.

An Anterior Cruciate Ligament Reconstruction Technique With 4-Strand Semitendinosus Grafts, Using Outside-In Tibial Tunnel Drilling and Suspensory Fixation Devices

We describe an anatomic single-bundle anterior cruciate ligament reconstruction using a 4-strand semitendinosus graft fixed with 2 Pullup adjustable suspensory fixation systems (SBM, Lourdes, France). Outside-in full tibial tunnel drilling represents a secure option for length management of the graft. The preferred graft choice is a 4-strand semitendinosus autologous graft. A special technique is used to stitch the graft with a figure-of-8 stitch to load the 4 strands. The Pullup adjustable loop is equipped with 2 buttons of different sizes: a small button for the standard Pullup system on the femoral side and a large button for the Pullup XL system on the tibial side. With this method, graft tension is equally distributed among the 4 strands and the graft cannot bottom out in the tibial tunnel in case of inadequate graft length.

Is height the best predictor for adequacy of semitendinosus-alone anterior cruciate ligament reconstruction? A study of hamstring graft dimensions and anthropometric measurements.

To predict adequacy of semitendinosus (ST) graft dimension for ACLR from anthropometric measures. Single tendon harvest for autograft hamstring ACLR could be beneficial to limit donor site morbidity; however, concerns for reconstruction failure based upon inadequate graft size may limit this surgical technique. To predict adequacy, prospectively, 108 patients who underwent ACLR by hamstring graft (STG graft) were enrolled for the study. Mean age was 33.028years±9.539 SD (14-59) with 88 males and 20 females. Anthropometric measurements (height, weight, BMI, thigh and total limb length) and intraoperative data (graft dimensions and bone tunnel measurements) were collected for analysis. Semitendinosus graft can be used as 3-strand (ST3) or 4-strand (ST4) graft. Adequacy criteria for ST3 and ST4 graft dimensions were determined from data analysis. SPSS (v.17) Pearson's correlation coefficient and ROC curves were used for statistical analyses. A total of 74 out of 108 patients (68.52%) had adequate graft dimensions for ST3 reconstruction. Height equal or greater than 158cm was predictive of adequate graft for ST3 reconstruction. Only 23 patients (21.3%) had adequate graft dimensions for ST4 reconstruction. Height equal or greater than 170cm was predictive of adequate graft for ST4 reconstruction. Height variable had the highest ROC curve area of 0.840 and 0.910 for both ST3 graft and ST4 graft, respectively. Hence, height was used as best predictor to determine adequacy of the graft. Height can be predictive of adequate graft for single tendon ACL reconstruction.

The sizing of hamstring grafts for anterior cruciate reconstruction: intra- and inter-observer reliability

The objective of this study was to establish the intra- and inter-observer reliability of hamstring graft measurement using cylindrical sizing tubes. Hamstring tendons (gracilis and semitendinosus) were harvested from ten cadavers by a single surgeon and whip stitched together to create ten 4-strand hamstring grafts. Ten sports medicine surgeons and fellows sized each graft independently using either hollow cylindrical sizers or block sizers in 0.5-mm increments—the sizing technique used was applied consistently to each graft. Surgeons moved sequentially from graft to graft and measured each hamstring graft twice. Surgeons were asked to state the measured proximal (femoral) and distal (tibial) diameter of each graft, as well as the diameter of the tibial and femoral tunnels that they would drill if performing an anterior cruciate ligament (ACL) reconstruction using that graft. Reliability was established using intra-class correlation coefficients. Overall, both the inter-observer and intra-observer agreement were >0.9, demonstrating excellent reliability. The inter-observer reliability for drill sizes was also excellent (>0.9). Excellent correlation was seen between cylindrical sizing, and drill sizes (>0.9). Sizing of hamstring grafts by multiple surgeons demonstrated excellent intra-observer and intra-observer reliability, potentially validating clinical studies exploring ACL reconstruction outcomes by hamstring graft diameter when standard techniques are used. III.

Smaller Graft Size is Associated with Poorer Outcomes and Increased Risk of Revision 2 Years After Primary ACL Reconstruction with Hamstring Autograft: A MOON Cohort Study

Smaller hamstring autograft size is correlated with lower KOOS and subjective IKDC scores two years following ACL reconstruction and graft size less than 8.5 mm is associated increased risk of revision ACL reconstruction, especially in younger patients. Hamstring autografts are frequently utilized for anterior cruciate ligament (ACL) reconstruction. Commonly used 4-strand grafts average about 8 mm in diameter but significant variation among patients has been noted. Previous retrospective studies have demonstrated increased failure rates with smaller grafts, particularly in younger patients. No studies have evaluated the effect of graft size on patient-reported outcomes following ACL reconstruction. We hypothesize that decreased hamstring autograft size is associated with poorer patient reported outcome scores and increased risk of revision ACL reconstruction. Through use of prospectively collected cohort data augmented with retrospective chart review, 263 of 320 consecutive patients (82.2%) undergoing primary ACL reconstruction with hamstring autograft at two academic centers were evaluated. Graft size, patient sex, femoral tunnel drilling technique, patient age and BMI at the time of ACL reconstruction, pre-operative and 2-year post-operative KOOS and IKDC scores, and whether each patient underwent revision ACL reconstruction during the 2 year follow-up period were recorded. The 263 patients included 144 males (54.8%) and ranged in age from 13 to 58 years (mean, 25.6 years). After controlling for age, sex, operative side, surgeon, BMI, and femoral tunnel drilling technique, a 1mm decrease in ACL graft size predicted a decrease the in KOOS-pain subscale by 3.0 points (p = 0.009), a decrease in the KOOS-sport/recreation function subscale by 4.6 points (p = 0.015), and a decrease in the subjective IKDC score by 2.9 points (p = 0.05). Fifteen of the 263 patients (5.7%) underwent revision ACL reconstruction. Two revisions were performed in the 178 patients over age 18 (1.1%), but 13 revisions were required in the 85 patients age 18 and under (15.3%) (p < 0.0001). Revision was required in 0 of 61 patients (0.0%) with grafts greater than 8mm in diameter and 14 of 202 patients (6.5%) with 8 mm or smaller grafts (p = 0.037). Among patients age 18 and under, revision was required in 0 of 14 patients (0.0%) with grafts greater than 8mm in diameter and 13 of 71 patients (18.3 %) with 8 mm or smaller grafts. Most failures (13 of 15) were noted to occur in patients age 18 and under with grafts 8mm in diameter or less. The revision rate in this population was 18.3% (13 of 71 patients). Smaller hamstring autograft size is a predictor of poorer patient-reported outcome scores 2 years following primary ACL reconstruction. Larger sample size is required to confirm the relationship between smaller graft size and increased risk of revision ACL reconstruction.

How to Improve the Prediction of Quadruple Semitendinosus and Gracilis Autograft Sizes with Magnetic Resonance Imaging and Ultrasonography

Objectives:To determine if preoperative ultrasonographic measurement of the cross-sectional area (CSA) of the gracilis tendon (GT) and semitendinosus tendon (ST) could predict the diameter of the quadrupled ST-GT autograft as accurately as the magnetic resonance imaging (MRI), and how different magnifications of the MRI slices could influence the accuracy of the measurement.Methods:33 patients scheduled for ACL reconstruction with hamstring autograft and with MRI performed at our institution were included. CSA of every GT and ST was calculated with ultrasonography (US) and with 2 different types of measurements on axial 1.5-T MRI at the widest point of the medial femoral epicondyle. In the first type of MRI measurement (MRI-2x method), the images were all analyzed under a 2x-magnified view while in the second type (MRI-4x method), under a 4x-magnified view with the method described by Hamada M et al (Figure 1). The CSA was calculated with the PACS workstation (Centricity Enterprise Web V3.0) with the region of interest tool. Every coupled GT and ST was doubled over around a suture and passed through a closed-hole sizing block. The smallest sizing hole through which the proximal end of the quadrupled ST+GT graft could be pulled with maximal manual force was the final diameter considered for the studyPurpose:Results:The Pearson correlation coefficient for the US cross- sectional area to the intraoperative graft diameter was 0.506 (p=0.003). When the CSA was major than 16 mm2 resulted in graft diameter of at least 8 mm in 100% of cases. The CSA on MRI of the GT + ST with the MRI-2x and MRI-4x methods were 27.2 ± 4.4 mm2 and 18.8 ± 2.8 mm2 respectively. Intraoperative graft diameter measurement positively correlated with preoperative MRI tendon CSA measurement with both measurement techniques. However, whether the correlation was only moderate with the MRI-2x method (0.536; p=0.001), it was excellent with the MRI-4x method (0.86; p<0.001) (Figure 2). With the MRI-2x measurement method, when the CSA was major than 25 mm2 resulted in graft diameter of at least 8 mm in 95% of the cases. With the MRI-4x measurement method, when the CSA was major than 17 mm2 resulted in graft diameter of at least 8 mm in 100% of cases.Conclusion:Preoperative calculation of the cross-sectional area of hamstring tendons with MRI and US can help to reliable estimate quadruple ST+GT graft. In terms of correlation of the CSA with graft diameter, US was comparable to MRI at 2x-magnification, but MRI at 4x-magnification showed superior accuracy. A ST+GT CSA threshold value of 25 mm2, 17mm2, and 16m2 with the MRI-2x, MRI-4x and US methods, respectively, predicted a 4-stranded graft of a minimum 8mm in diameter.

Anatomy of the anterior cruciate ligament related to hamstring tendon grafts. A cadaveric study

BackgroundThe aim of modern techniques for anatomic reconstruction of the ACL is to reproduce ACL footprints, in order to restore anatomy and therefore normal biomechanics. Is there an oversizing of the hamstring grafts related to ACL dimensions? MethodsTwenty-two paired cadaver knees were dissected. ACL dimensions at mid-portion and ACL footprints were measured after removing the synovial membrane.Hamstrings were harvested and prepared in a quadruple strand graft in order to measure the mean circumference. ResultsThe average ACL tibial and femoral insertion site areas of the ACL were 117.9mm2 (range, 90 to 130mm) and 96.8mm2 (range, 80 to 121mm), respectively.The average diameter and cross sectional area of the ACL tendon at mid-portion were 6.1mm (range, 5 to 7mm) and 29.2mm2 (range, 20 to 38.9), respectively. The average diameter and cross-sectional area of the 4-stranded hamstring tendons were 6.7 (range, 5 to 8) and 35.3mm2 (range, 20 to 50), respectively.There was a correlation between the 4-stranded hamstring grafts and ACL dimensions (footprints, ligament at mid substance, p<0.01). The cross sectional area of hamstring tendon was significantly larger than the ACL area at mid-portion (mean 20.9%, p<0.05). ConclusionWith current ACL reconstruction techniques, the graft is oversized at a mean of 21%, despite a good correlation between the ACL and the hamstring tendon, especially among small subjects and women. The question arises whether the anatomic reconstruction of the ACL should fill ACL footprints or mimic the ligament itself. Clinical relevanceHamstrings grafts are significantly larger than native ACL.

A New Anterior Cruciate Ligament Reconstruction Fixation Technique (Quadrupled Semitendinosus Anterior Cruciate Ligament Reconstruction With Polyetheretherketone Cage Fixation)

Fixation of the graft during anterior cruciate ligament reconstruction surgery has been the subject of numerous technical innovations but still remains a challenge. This article describes a novel technique of graft fixation for hamstring tendon reconstruction: the Cage For One system (Sacimex, Aix-en-Provence, France). The technique uses only the semitendinosus tendon, which is looped to create a 4-strand graft. Leaving the gracilis tendon intact probably reduces the loss of knee flexion strength. The graft is indirectly anchored into both tunnels with polyetheretherketone cages by use of polyethylene terephthalate tape strips. Both cages and strips are magnetic resonance imaging compatible and do not create artifacts. The tunnels are drilled by an outside-in method with minimal incisions. This type of fixation creates a 360° bone contact at 1.5 cm in each tunnel and is compatible with double-bundle reconstruction. This easy-to-use novel technique of fixation for anterior cruciate ligament reconstruction produces a strong 4-strand graft while harvesting only the semitendinosus tendon and leaving the gracilis tendon intact to reduce flexion strength loss and preserve rotatory stability of the knee. It creates an immediate solid fixation that is independent of graft integration in the early postoperative period, allowing the patient to start immediate rehabilitation without the use of a brace.

Double-Bundle Anterior Cruciate Ligament Reconstruction: The Italian Experience

In our original technique, semitendinosus/gracilis tendons are harvested without detaching their tibial insertion, and sutures are tightened at their free proximal extremities. The tibial tunnel is performed in the medial-posterior portion of the native anterior cruciate ligament tibial insertion. For the femoral tunnel, the knee is flexed at 130° and the guide pin is advanced in the 9:30 clockwise position until it passes the lateral femoral condyle cortex. The exit point in the lateral aspect of the femur has to be immediately above the end of the lateral femoral condyle. After the lateral incision, the tendons are passed over the top. The correct placement is found by palpating the posterior tubercle of the lateral femoral condyle. The stitches on the free proximal end of the tendons are tied onto the passing suture that is pulled through the joint to the over the top position. A suture loop is introduced into the joint through the anteromedial portal using a suture passer and then pulled into the femoral tunnel under the arthroscopic view. The stitches on the free end of the tendons are looped again onto the passing suture, which is pulled through the femoral tunnel, the knee joint, and the tibial tunnel to retrieve back the graft from the tibial incision. The combined gracilis and semitendinosus graft are then tensioned and fixed with a transosseous suture or a staple. This technique reproduces the kinematic effect of posterolateral and anteromedial anterior cruciate ligament bundles with a 4-stranded graft, although achieving a better anatomic and functional result.

Prediction of the Graft Size of 4-Stranded Semitendinosus Tendon and 4-Stranded Gracilis Tendon for Anterior Cruciate Ligament Reconstruction

Background: Little information is available regarding parameters that would enable a surgeon to predict the size and length of 4-stranded semitendinosus (ST) and 4-stranded gracilis tendon (GT) grafts. Purpose: To evaluate whether certain preoperative anthropometric data enable prediction of the size of 4-stranded ST and GT autograft for anterior cruciate ligament (ACL) reconstruction. Study Design: Cohort study (prevalence); Level of evidence, 2. Methods: This study involved 235 Chinese Han patients who underwent double-bundle ACL reconstruction with 4-stranded autogenous ST and GT grafts. Preoperatively, the authors recorded height, weight, body mass index (BMI), gender, age, and sports activity. During surgery, the usable length of the ST and GT and the diameter of the 4-stranded grafts made of ST and GT were measured. Multiple regression analysis was used to determine relationships between anthropometric measurements and the length and diameter of intraoperatively measured ST and GT grafts. Results: Strongest correlations for ST and GT length and GT graft diameter were height and weight. The strongest correlations for ST graft diameter were gender and weight. Body mass index had only moderate correlations with ST and GT graft size. Self-reported activity level was not correlated. Women had significantly smaller GT and ST graft diameters and shorter tendon lengths than did men. Semitendinosus graft size was significantly larger and longer than was the GT graft (7.4 ± 0.7 mm vs 5.9 ± 0.6 mm and 279.9 ± 20.8 mm vs 251.5 ± 20.8 mm, respectively). Simple regression analysis demonstrated that height, weight, and BMI can be used to predict ST and GT autograft length and diameter. Conclusion: Several preoperative anthropometric measurements showed correlation with the length of the ST and GT and diameter of 4-stranded ST and GT grafts. The current data may provide surgeons with important preoperative information about size of ST and GT grafts and would be useful for patient counseling and alternative graft source planning.

Effects of graft pretensioning in anterior cruciate ligament reconstruction

Graft pretensioning is used in anterior cruciate ligament (ACL) reconstruction to prevent secondary slackening. Its effects on collagen fibrillar ultrastructure are not known. In this study, we hypothesized that graft pretensioning in ACL reconstruction creates ultrastructural changes detectable in scanning electron microscopy (SEM). A prospective comparative study was carried out on 38 ACL reconstructions using a 4-strand semitendinosus graft. Samples were harvested intra-operatively before and after pretensioning for 30s, 2 or 5min. The images produced in SEM were analyzed using an original semi-quantitative «CIP» score taking into account collagen cohesion, integrity, and parallelism. Intra- and inter-tester reliability for the CIP score were tested. The CIP scores decreased by 3.5 (1.6) points after pretensioning (P<0.05). Significant differences were found in the 5, 2min and 30s subgroups for the global CIP score. Relative decrease (Delta CIP) was significantly higher in the 2 and 5min subgroups after pretensioning in comparison with the 30s subgroups. Intra- and inter-tester reliability for the CIP score were 0.85 and 0.92 (P<0.05). Pretensioning ACL grafts resulted in alteration of the collagen fibrillar ultrastructure, detectable using SEM. These results confirm the existence of collagen ultrastructural changes after pretensioning that may be related to its duration. Prospective comparative study, Level II.

Tibial Fixation of Anterior Cruciate Ligament Allograft Tendons

Background In sum, 1-, 2-, and 4-stranded allografts are used for soft tissue anterior cruciate ligament reconstruction; however, the fixation properties of fixation devices are not well assessed. Hypothesis There are no differences in the biomechanical characteristics of 1 (Achilles)-, 2 (posterior tibialis)-, and 4 (semitendinosus)-stranded allograft tibial fixation. Study Design Controlled laboratory study. Methods Sixty-three fresh-frozen porcine tibiae were used to evaluate the fixation of 1-, 2-, and 4-stranded human tendon allografts (Achilles, posterior tibialis, and semitendinosus) with 3 fixation devices (Delta, Intrafix, and Calaxo screws). With use of a materials testing system, each graft was subjected to 500 cycles of loading (50-250 N, 0.75 mm/sec) to determine displacement and cyclic stiffness, followed by a monotonic failure test (20 mm/min) to determine maximum load and pullout stiffness. Results For each graft type, there were no significant biomechanical differences between fixation devices. However, the 1-stranded graft (Achilles) construct demonstrated significantly higher mean displacement (3.17 ± 1.62 mm), lower cyclical stiffness (156 ± 25 N/mm), lower load to failure (479 ± 87 N), and lower pullout stiffness (140 ± 28 N/mm). In comparison with the 2-stranded graft (posterior tibialis), the 4-stranded graft (semitendinosus) exhibited lower displacement (0.86 ± 0.44 to 1.12 ± 0.51 mm) and higher ultimate failure load (832 ± 255 to 656 ± 168 N). Numerous differences in fixation properties were noted when comparing a device to each of the 3 grafts. Conclusion The 1-stranded allograft demonstrated inferior biomechanical tibial fixation properties when compared with 2 (posterior tibialis)- and 4 (semitendinosus)-stranded allograft constructs for all fixation devices tested. Clinical Relevance This study demonstrated that not all tibial fixation devices are designed to adequately accommodate different types of anterior cruciate ligament allografts. Biomechanical evidence suggests that caution is warranted when using an Achilles allograft fixated solely with an interference device.

Tensioning of Anterior Cruciate Ligament Hamstring Grafts: Comparing Equal Tension Versus Equal Stress

A biomechanical study was undertaken to determine whether equal-stress or equal-tension tensioning of anterior cruciate ligament 4-stranded semitendinosus and gracilis grafts provides a stronger graft construct when testing to ultimate failure. Eighteen fresh-frozen cadaveric semitendinosus and gracilis tendons were each positioned over a cylinder rod/cryo-clamp connected to an MTS machine (MTS Systems, Eden Prairie, MN) by another cryo-clamp. In the equal-tension group the 4 strands were equally tensioned by weights. In the equal-stress group a tensioning device applied equal stress based on the cross-sectional areas of the tendons. The tendons were preconditioned with 10 cycles and then tested to failure. Graft creep during the preconditioning cycle was determined by MTS measurement of the change in clamp distance. The maximum loads of 4-stranded semitendinosus and gracilis grafts tensioned by equal stress were found to be similar to those of the grafts tensioned by equal tension (2,803 +/- 431 N and 2,772 +/- 461 N, respectively). The loads at first failure were 2,640 +/- 468 N and 2,452 +/- 461 N, respectively (P = .17). The preconditioning cycles showed that the equal-stress group resisted graft creep significantly better (P = .0003). The strength of the 4-stranded hamstring graft when equally tensioned or equally stressed was equivalent when tested to failure. After 10 preconditioning cycles, equal stress resisted graft creep significantly better. Equal-stress tensioning offers an alternative tensioning method for 4-stranded hamstring grafts. Equal-stress tensioning offers an alternative tensioning method for 4-stranded hamstring grafts.

Simultaneous Double-Bundle Anterior Cruciate Ligament and Posterior Cruciate Ligament Reconstruction With Autogenous Hamstring Tendons

The purpose of this study was to evaluate the clinical results of simultaneous double-bundle anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction. We performed arthroscopic reconstruction in 21 cases of combined ACL/PCL rupture, 14 chronic and 7 acute, with autogenous hamstring tendons in 1 stage, both in a double-bundle and 4-tunnel manner. The semitendinosus tendon and gracilis tendon from the uninjured leg were used to make two 4-stranded grafts to reconstruct the PCL, and those from the injured leg were used to make two 4-stranded grafts to reconstruct the ACL. The grafts were suspended with a mini-plate and buttons. The patients were followed up for a minimum of 2 years and evaluated according to the International Knee Documentation Committee (IKDC) and Lysholm rating scale. The anterior-posterior knee laxity was assessed by KT-1000 examination (MEDmetric, San Diego, CA). At the last follow-up, all patients showed normal knee extension. One patient had a 10 degrees flexion limitation, and four had a 5 degrees flexion limitation. KT-1000 examination showed that the side-to-side difference in overall anterior-posterior laxity at 70 degrees flexion was 0 to 2 mm in 16 patients, 3 to 5 mm in 4 patients, and 6 to 10 mm in 1 patient; the side-to-side difference in overall anterior-posterior laxity at 25 degrees flexion was 0 to 2 mm in 14 patients, 3 to 5 mm in 6 patients, and 6 to 10 mm in 1 patient. The IKDC subjective, Lysholm, and Tegner scores were 85.5 +/- 5.8, 91.9 +/- 4.2, and 5.0 +/- 1.9, respectively. According to the last IKDC evaluation, the results were graded as normal in 13 patients (61.9%), nearly normal in 7 patients (33.3%), and abnormal in 1 patient (4.8%). Simultaneous double-bundle ACL and PCL reconstruction with autogenous hamstring tendons can yield normal results in 61.9% of patients and nearly normal results in 33.3% at a minimum of 2 years. Level IV, therapeutic case series.

Double-Bundle Anterior Cruciate Ligament Reconstruction: The Italian Experience

In our original technique, semitendinosus/gracilis tendons are harvested without detaching their tibial insertion, and sutures are tightened at their free proximal extremities. The tibial tunnel is performed in the medial-posterior portion of the native anterior cruciate ligament tibial insertion. For the femoral tunnel, the knee is flexed at 130° and the guide pin is advanced in the 9:30 clockwise position until it passes the lateral femoral condyle cortex. The exit point in the lateral aspect of the femur has to be immediately above the end of the lateral femoral condyle. After the lateral incision, the tendons are passed over the top. The correct placement is found by palpating the posterior tubercle of the lateral femoral condyle. The stitches on the free proximal end of the tendons are tied onto the passing suture that is pulled through the joint to the over the top position. A suture loop is introduced into the joint through the anteromedial portal using a suture passer and then pulled into the femoral tunnel under the arthroscopic view. The stitches on the free end of the tendons are looped again onto the passing suture, which is pulled through the femoral tunnel, the knee joint, and the tibial tunnel to retrieve back the graft from the tibial incision. The combined gracilis and semitendinosus graft are then tensioned and fixed with a transosseous suture or a staple. This technique reproduces the kinematic effect of posterolateral and anteromedial anterior cruciate ligament bundles with a 4-stranded graft, although achieving a better anatomic and functional result.

Supplemental Tibial Fixation for Anterior Cruciate Ligament Reconstruction

This report describes transosseous backup suture fixation for anterior cruciate ligament (ACL) grafts of all varieties, used to distally augment proximal screw fixation in the tibia. Using a simple suture configuration, this method secures the ACL graft to the tibial cortex in conjunction with a proximal interference screw. The technique is applicable for all graft configurations, including allograft, autograft, bone, and both 2- and 4-strand soft-tissue grafts. The described technique is intended to be used for secondary or backup fixation of the graft in the tibial tunnel and not as primary fixation. This construct can be reproducibly created, making use of the sutures that are typically present on the graft after the interference screw is placed. This technique for backup tibial fixation precludes the need for external hardware, which in many instances may be symptomatically proud. Furthermore, use of this technique may represent a potential cost savings because no additional devices or equipment is used or purchased. This technique is simple, fast, and inexpensive, making use of available constructs to enhance the security of graft fixation during ACL reconstruction.