Hyperflexion and Femoral Interference Screw Insertion in ACL Reconstruction.

BACKGROUND: In anatomic anterior cruciate ligament (ACL) reconstructions produced with flexible reamers and no knee hyperflexion, it is unknown whether knee hyperflexion is necessary for femoral interference screw insertion. PURPOSE: To compare femoral screw-graft divergence in anatomic ACL reconstructions with endoscopic interference screws placed without knee hyperflexion and with the use of flexible versus rigid screwdrivers. STUDY DESIGN: Controlled laboratory study. METHODS: Ten matched pairs of cadaveric knees had bone-tendon-bone graft ACL reconstructions with anatomic femoral tunnels. The knees were flexed to 90°. Femoral interference screws (7 × 20 mm) were placed in pairs of knees: in 1 knee with a flexible screwdriver and in the opposite knee with a rigid screwdriver. Graft-screw divergence was imaged with computed tomography scans and tested with cyclic and static biomechanical tests. RESULTS: The mean screw-graft divergence was 12.07° ± 4.04° with the rigid screwdriver and 10.68° ± 3.23° with the flexible screwdriver (P = .35). The cyclic tests with screws placed by a rigid screwdriver had a mean increase in displacement of 0.56 ± 0.20 mm. For screws placed with the flexible screwdriver, the mean increase in displacement was 0.58 ± 0.32 mm (P = .66). Yield load was 393.3 ± 95.1 N for screws placed by a rigid screwdriver and 408.2 ± 119.0 N for screws inserted with the flexible screwdriver (P = .78). Maximum load was 523.1 ± 88.7 N for screws placed by a rigid screwdriver and 467.1 ± 107.3 N for screws inserted with the flexible screwdriver (P = .09). CONCLUSION: With either a rigid or a flexible screwdriver, there were no significant effects on screw divergence or fixation strength. CLINICAL RELEVANCE: Knees can be kept at 90° during endoscopic femoral interference screw insertion. The use of a traditional rigid or flexible screwdriver will not affect screw-graft divergence or fixation strength.

Height and Depth Guidelines for Anatomic Femoral Tunnels in Anterior Cruciate Ligament Reconstruction: A Cadaveric Study.

PURPOSE: To develop guidelines for femoral tunnel placement based on height and depth on the lateral wall of the notch and to apply these guidelines arthroscopically to show tunnel placements within the anterior cruciate ligament (ACL) femoral insertion site. METHODS: Twelve cadaveric knees were dissected to define the centers of the femoral ACL attachment and its anteromedial (AM) and posterolateral (PL) bundles. In 90° of flexion, the height and depth of each center were determined relative to the low point on the lateral intercondylar notch. Radiographic grid measurements were made to validate these measurements. Subsequently, the measurement guidelines were applied arthroscopically in 10 new cadaveric knees to evaluate their accuracy for an anatomic single-bundle femoral tunnel. Interobserver reliability analysis was evaluated with the intraclass correlation coefficient. RESULTS: In 90° of flexion, the height of the ACL center was 8.7 ± 0.6 mm from the low point of the lateral notch; PL center, 7.2 ± 1.2 mm; and AM center, 9.6 ± 1.1 mm. Relative to the low point, the ACL center was 1.7 ± 1.7 mm posterior, the PL center was 3.4 ± 1.5 mm anterior, and the AM center was 4.9 ± 1.7 mm posterior (intraclass correlation coefficient, 0.859). Radiographic grid measurements were consistent with the direct measurements. Application of the guidelines arthroscopically with or without the assistance of a 7-mm offset aimer placed all guide pins for tunnels within the femoral ACL footprint, with 90% within 4 mm of the ACL center. CONCLUSIONS: This study showed in cadaveric knees in 90° of flexion that the center of the ACL can be located on the lateral notch at a height of 8.7 ± 0.6 mm from the lowest point and anterior 11.5 ± 1.3 mm from the deepest point. How anatomic tunnels can be placed using these measurements was also shown in cadaveric knees. CLINICAL RELEVANCE: An anatomic femoral tunnel for ACL reconstruction can be placed using height and depth guidelines.

Full-Contact Practice and Injuries in College Football.

BACKGROUND: Despite recent restrictions being placed on practice in college football, there are little data to correlate such changes with injuries. HYPOTHESIS: Football injuries will correlate with a team's exposure to full-contact practice, total practice, and total games. STUDY DESIGN: Descriptive epidemiological study. METHODS: All injuries and athlete injury exposures (AE × Min = athletes exposed × activity duration in minutes) were recorded for an intercollegiate football team over 4 consecutive fall seasons. Weekly injuries and injury rates (injuries per athletic injury exposure) were correlated with the weekly exposures to full-contact practices, total practices, formal scrimmages, and games. RESULTS: The preseason practice injury rate was over twice the in-season practice injury rate ( P < 0.001). For preseason, injury exposures were higher for full-contact practice ( P = 0.0166), total practices ( P = 0.015), and scrimmages/games ( P = 0.034) compared with in-season. Preseason and in-season practice injuries correlated with exposure to full-contact practice combined with scrimmages for preseason ( P < 0.008) and full-contact practice combined with games for in-season ( P = 0.0325). The game injury rate was over 6 times greater than the practice injury rate ( P < 0.0001). Concussions constituted 14.5% of all injuries, and the incidence of concussions correlated with the incidence of all injuries ( P = 0.0001). Strength training did not correlate with injuries. CONCLUSION: Decreased exposure to full-contact practice may decrease the incidence of practice injuries and practice concussions. However, the game injury rate was over 6 times greater than the practice injury rate and had an inverse correlation with full-contact practice.

Flexible instruments outperform rigid instruments to place anatomic anterior cruciate ligament femoral tunnels without hyperflexion.

PURPOSE: This study evaluated the ability of flexible instruments compared with rigid instruments to place anatomic femoral tunnels in anterior cruciate ligament reconstructions by use of both transtibial drilling and anteromedial drilling without hyperflexion. METHODS: Rigid and flexible pins were placed in 12 matched pairs of cadaveric knees with transtibial drilling (6 pairs) and anteromedial drilling (6 pairs) at 110° of flexion. Intraosseous pin lengths, femoral exit locations, and tunnel alignment were measured. RESULTS: Transtibial drilling with rigid pins placed relatively vertical femoral tunnels 5.8 ± 1.0 mm superior to the central anterior cruciate ligament insertion. Transtibial drilling with flexible pins placed tunnels in the center of the femoral attachment, but the tunnels were relatively close to the posterior femoral cortex, with a mean distance of 8.0 ± 5.9 mm (P < .05), compared with transtibial drilling with rigid pins. Anteromedial drilling resulted in central anatomic pin placements with rigid and flexible instruments. Tunnel lengths with flexible pins were longer (42.0 ± 7.2 mm) compared with tunnel lengths with rigid pins (32.5 ± 7.1 mm) (P < .01). Flexible pins exited farther from the posterior cortex compared with rigid pins (P < .01). In 3 of 6 knees with rigid pins, the exit point was at the posterior border of the femoral cortex. All flexible pins exited a safe distance from the posterior femoral cortex. CONCLUSIONS: Transtibial drilling with rigid instruments did not produce anatomic femoral tunnels. Transtibial drilling with flexible pins produced anatomic tunnels, but the tunnels were close to the posterior femoral cortex. Anteromedial drilling without hyperflexion produced anatomic tunnels by use of rigid and flexible instruments, but with flexible instruments, the tunnels were longer and were farther from the posterior femoral cortex. Anteromedial drilling with flexible pins produced tunnels with good length and the best position. CLINICAL RELEVANCE: Flexible instruments compared with rigid instruments can facilitate the creation of anatomic femoral tunnels by use of anteromedial drilling without hyperflexion.

Osteotomies about the knee for tibiofemoral malalignment in the athletic patient.

Osteotomies have a role in the active patient with degenerative joint disease of the medial or lateral knee who, for reasons of age or activity level, is not yet a good candidate for prosthetic arthroplasty. Recognition and treatment of malalignment associated with ligamentous instability is essential if long-term good outcomes are to be expected from ligamentous reconstruction. Also, treatment of concomitant malalignment and the unloading of the operative site is now recognized as an important adjunct to any cartilage-preserving surgery. This review examines the use of osteotomies about the knee in the athletic patient. Indications, contraindications, preoperative planning, surgical techniques, and complications are reviewed.

Independent drilling outperforms conventional transtibial drilling in anterior cruciate ligament reconstruction.

BACKGROUND: Optimal tunnel placement is critical in anterior cruciate ligament reconstructive surgery, yet the method used to drill the tunnels may compromise their placement. HYPOTHESIS: An independent drilling method versus a conventional transtibial drilling method will place tunnels in different locations and produce reconstructions with different kinematics. STUDY DESIGN: Controlled laboratory study. METHODS: Ten pairs of knees had anterior cruciate ligament reconstructions produced by either a conventional transtibial drilling method or an independent drilling method. The location of the tunnels was recorded, and the knees were tested for laxity in the normal state, with the anterior cruciate ligament removed, and with the anterior cruciate ligament reconstructed. A surgical navigation system guided the placement of the independently drilled tunnels and measured joint laxity in response to various combinations of anterior force and rotational torques. RESULTS: The conventional transtibial drilling method used in this study placed tibial tunnels posterior and femoral tunnels superior relative to their footprints and resulted in more vertical grafts. In contrast, the independently drilled tibial and femoral tunnels were more anterior and central in their respective footprints, resulting in more horizontal grafts. The horizontal grafts of the independent drilling method were superior to the vertical grafts of this study's transtibial drilling method in restoring normal anterior and rotational knee laxity. CONCLUSION: An independent drilling method can produce tunnels with superior function compared with tunnels produced by a conventional transtibial drilling method. CLINICAL RELEVANCE: Single-bundle anterior cruciate ligament reconstructions will be improved if grafts are centered in their anatomical insertions by an independent drilling method versus grafts placed by a conventional transtibial drilling method.

Independent drilling of tibial and femoral tunnels in anterior cruciate ligament reconstruction.

Anterior cruciate ligament (ACL) reconstruction can be optimized when single-bundle grafts are centered within the native ligament's tibial and femoral insertions. An understanding of ACL anatomy, including surgical landmarks for tunnel placement, is critical to accomplish this task. The best method for placing the femoral tunnel requires the independent, rather than a transtibial, drilling of the femoral tunnel. A good option for drilling the femoral tunnel is to drill through an anteromedial portal, but this method is challenging because it requires a high angle of knee flexion and visualization of the femoral insertion is limited during drilling. This review provides a rationale for independent tunnel drilling in ACL reconstruction, a method for identifying the insertional anatomy of the ACL, and a method for drilling the femoral tunnel through the anteromedial portal.

Equal kinematics between central anatomic single-bundle and double-bundle anterior cruciate ligament reconstructions.

PURPOSE: The purpose of this study was to compare the kinematics of a central anatomic single-bundle anterior cruciate ligament (ACL) reconstruction with a double-bundle ACL reconstruction by use of hamstring grafts and anatomic tunnel placement. METHODS: Anterior tibial translation and rotation were measured with a computer navigation system in 8 pairs of fresh-frozen cadaveric knees by use of a 133-N anterior force, an internal and external torque of 10 Nm, and an anterior force (133 N) combined with an internal rotation torque (10 Nm). Tests were performed at 30 degrees and 60 degrees of flexion with the ACL intact, the ACL transected, and after reconstruction of one side of a pair with either a single or a double-bundle construct. RESULTS: At 30 degrees of flexion, cutting the ACL increased anterior translation under an anterior force (P < .0001), an internal rotation torque (P = .02), and a combined anterior force plus internal rotation torque (P = .01). At 60 degrees of flexion, transecting the ACL led to increased anterior translation only when an anterior force was used (P < .0001). Both single- and double-bundle reconstructions restored normal kinematics at 30 degrees and 60 degrees of knee flexion. CONCLUSIONS: Central anatomic single-bundle ACL reconstruction with tunnels centered within the tibial and femoral insertions and double-bundle ACL reconstruction can restore normal anterior translation to the knee under anterior and rotational loads applied at 30 degrees and 60 degrees of flexion. CLINICAL RELEVANCE: The primary kinematic effect of an ACL injury is an increase in anterior tibial translation, but there is no significant change in maximum internal or external rotation. Single- and double-bundle ACL reconstructions are equally effective in restoring normal anterior translation to the knee under both anterior and rotational loads.

Strategies to improve anterior cruciate ligament healing and graft placement.

Recent improvements in anterior cruciate ligament (ACL) reconstruction have been notable for strategies to improve ACL healing and to improve graft placements. The controversial choice of 1-bundle or 2-bundle grafts requires an advanced knowledge of native ACL insertional anatomy and an appreciation for the kinematic effects of graft placements. Understanding the limitations of surgical techniques to place tunnels is important. Once grafts are placed, new biologic strategies to promote intra-articular and intraosseous healing are evolving. Although these biologic engineering strategies are currently experimental, they are projected for clinical application in the near future.

Anatomical limitations of transtibial drilling in anterior cruciate ligament reconstruction.

BACKGROUND: Recommended techniques for transtibial drilling in anterior cruciate ligament reconstruction are based on strategies to prevent graft impingement and preserve tibial tunnel length. The limitations of this drilling technique may restrict the ability to centralize tunnels in the anterior cruciate ligament footprints. HYPOTHESIS: A transtibial drilling starting point to centralize the tibial and femoral tunnels in their respective footprints can be identified, but it will result in a short tibial tunnel. STUDY DESIGN: Descriptive laboratory study. METHODS: The femoral and tibial attachments of the anterior cruciate ligament were characterized in 12 fresh-frozen cadaveric knees. Knees were secured in 70 degrees and 90 degrees of flexion. A guide pin was drilled antegrade through the central femoral and proximal anterior cruciate ligament attachment sites through the central tibial anterior cruciate ligament attachment site to exit on the anterior tibia. RESULTS: In 90 degrees of flexion using the central femoral and tibial attachment sites, the exit point of the pin on the anterior tibia was 14.1 mm from the tibial joint line and 20.9 mm anterior to the superficial medial collateral ligament. The length of the pin in the tibia was 30.6 mm. Extending the knee to 70 degrees or directing the pin through the proximal femoral anterior cruciate ligament attachment moved the starting point less than 4 mm from this point. CONCLUSION: The transtibial technique can produce tunnels centered in the anterior cruciate ligament footprints, but a starting point close to the tibial joint line is required. This will result in a relatively short tibial tunnel. CLINICAL RELEVANCE: If tunnels centered in the anterior cruciate ligament attachment sites are desired with the transtibial drilling technique, then a short tibial tunnel is necessary. A short tibial tunnel may compromise graft fixation and graft incorporation, or it may result in a tunnel length-graft length mismatch. An alternative drilling strategy might be employed.

Team physicians in college athletics.

BACKGROUND: There has been little documentation of what constitutes the clinical work of intercollegiate team physicians. Team physicians could be recruited based on the needs of athletes. HYPOTHESIS: A multidisciplinary team of physicians is necessary to treat college athletes. Most physician evaluations are for musculoskeletal injuries treated nonoperatively. STUDY DESIGN: Descriptive epidemiology study. METHODS: For a 2-year period, a database was created that recorded information on team physician encounters with intercollegiate athletes at a major university. Data on imaging studies, hospitalizations, and surgeries were also recorded. The diagnoses for physician encounters with all undergraduates through the university's health service were also recorded. RESULTS: More initial athlete evaluations were for musculoskeletal diagnoses (73%) than for general medical diagnoses (27%) (P < .05). Four percent of musculoskeletal injuries required surgery. Most general medical evaluations were single visits for upper respiratory infections and dermatologic disorders, or multiple visits for concussions. Football accounted for 22% of all physician encounters, more than any other sport (P < .05). Per capita, men and women sought care at an equal rate. In contrast, 10% of physician encounters with the general pool of undergraduates were for musculoskeletal diagnoses. Student athletes did not require a greater number of physician encounters than did the general undergraduate pool of students on a per capita basis. CONCLUSION: Intercollegiate team physicians primarily treat musculoskeletal injuries that do not require surgery. General medical care is often single evaluations of common conditions and repeat evaluations for concussions.

The biomechanical effects of low-dose irradiation on bone-patellar tendon-bone allografts.

BACKGROUND: Despite evidence that low-dose irradiation of 2 Mrad (20 kGy) is not virucidal for patellar tendon allografts and reduces tissue strength, many tissue bank protocols include low-dose irradiation. HYPOTHESIS: Maintaining tissue mechanical integrity may be particularly relevant toward accelerated rehabilitation of the injured knee, where the cyclic function of patellar tendon allografts is critical. STUDY DESIGN: Controlled laboratory study. METHODS: The cyclic and failure mechanical properties of paired bone-patellar tendon-bone allografts, with and without current low-dose irradiation of 20 kGy, were evaluated. Specimens were loaded from 50 N to 250 N for 1000 cycles at 0.5 Hz and subsequently loaded to failure at a strain rate of 100% per second. RESULTS: After 1000 cycles, grafts elongated 27% more when irradiated than when not (4.4 +/- 1.5 mm vs 3.4 +/- 1.0 mm; P = .03). Failure load averaged 1965 +/- 512 N for irradiated grafts and 2457 +/- 647 N for nonirradiated grafts (P = .007). CONCLUSIONS: The diminished strength of irradiated grafts may contribute to overt anterior cruciate ligament graft failure, and the increase in cyclic elongation may also be detrimental to graft function. CLINICAL RELEVANCE: These results suggest that one should consider the use of nonirradiated allografts as an alternative to irradiated grafts in anterior cruciate ligament reconstruction.