Editorial Commentary: Proper Anterior Cruciate Ligament Graft Choice Mitigates Against the Need for Anterolateral Ligament Reconstruction.

It is not coincidence that fervor surrounding anterolateral ligament (ALL) reconstruction increased as double-bundle anterior cruciate ligament reconstruction (ACLR) enthusiasm cooled. But perhaps we shifted our focus too soon, or perhaps we shifted our focus too much. But we must remember that the ACL is primary. Increases in ACL graft diameter by 1 or 2 mm can significantly increase graft strength and decrease revision rate. Biomechanical and clinical evidence suggests that quadriceps tendon ACLR and patellar tendon ACLR demonstrates less pivot shift phenomena than hamstring ACLR. In addition, As biologically active suture tapes become more mainstream, augmented allografts are an increasingly attractive option. Proper ACL graft choice mitigates against the need for ALL reconstruction. Risk factors for anterolateral rotatory instability may include low body mass index and lateral meniscal pathology, in addition to the well-known risks such as age, gender, activity level, and revision cases. Perhaps lateral extra-articular tenodesis should be reserved for high-risk cases.

Quadriceps tendon autograft ACL reconstruction has less pivot shift laxity and lower failure rates than hamstring tendon autografts.

PURPOSE: Quadriceps tendon (QT) autograft ACL reconstruction was hypothesized to possess less anterior knee laxity, pivot shift laxity, and lower failure rates than hamstring tendon (HT) autografts. METHODS: Terms "hamstring tendon autograft" and "ACL reconstruction" or "quadriceps tendon autograft" and "ACL reconstruction" were searched in Embase and PubMed. Inclusion criteria required that studies included patients treated for primary ACL injury with reconstruction using either a QT autograft (Group 1) or a HT autograft (Group 2) and instrumented anterior knee laxity assessment. Extracted information included surgical fixation method, graft type, graft thickness or diameter, single vs. double bundle surgical method, publication year, time between the index knee injury and surgery, % women, initial and final subject number, subject age, follow-up length, side-to-side anterior knee laxity difference, Lysholm Score, Subjective IKDC score, anterior knee laxity side-to-side difference grade, ipsilateral pivot shift laxity grade, and failure rate. The Methodological Index for Nonrandomized Studies was used to evaluate study methodological quality. RESULTS: The QT group (Group 1) had 17 studies and the HT group (Group 2) had 61 studies. Overall, Group 2 had greater pivot shift laxity (OR 1.29, 95% CI 1.05-1.59, p = 0.005). Group 2 suspensory femoral fixation had greater pivot shift laxity (OR 1.26, 95% CI 1.01-1.58, p = 0.02) than Group 1 compression femoral fixation. Group 2 compression femoral fixation also had more anterior knee laxity (OR 1.25, 95% CI 1.03-1.52, p = 0.01) than Group 1 compression femoral fixation and higher failure rates based on initial (OR 1.69, 95% CI 1.18-2.4, p = 0.002) and final (OR 1.89, 95% CI 1.32-2.71, p = 0.0003) subject number. Failure rate for HT compression femoral fixation was greater than suspensory femoral fixation based on initial (OR 2.08, 95% CI 1.52-2.84, p < 0.0001) and final (OR 2.26, 95% CI 1.63-3.16, p < 0.0001) subject number. CONCLUSIONS: Overall, QT autografts had less pivot shift laxity and lower failure rates based on final subject number than HT autografts. Compression QT autograft femoral fixation had lower pivot shift laxity than suspensory HT autograft femoral fixation. Compression QT autograft femoral fixation had less anterior knee laxity and lower failure rates than compression HT autograft femoral fixation. Suspensory HT autograft femoral fixation had lower failure rates than compression HT autograft femoral fixation. Greater knee laxity and failure rates may be related to a combination of HT autograft diameter and configuration (tissue quality and dimensions, strands, bundles, and suturing method) variability and fixation mode. LEVEL OF EVIDENCE: Level IV.

Tissue healing following segmental meniscal allograft transplantation: a pilot study.

PURPOSE: This in vivo histological study using an ovine model evaluated the 90-day healing of unilateral segmental meniscal allograft transplantation. METHODS: Fresh-frozen medial menisci were transplanted to replace the right medial meniscus of six female sheep. Tissue healing was evaluated using semi-quantitative, descriptive methods. Formalin-fixed meniscal, distal femur and proximal tibia tissues were evaluated using Rodeo (cellularity/collagen), Ishida (reparative bonding), Collagen I IHC (collagen I), and Mankin (cartilage organization) scores at the medial femoral condyle (MFC) and medial tibial plateau (MTP). Meniscocapsular evaluations were performed at the: (a) peripheral junction; (b) posterior sector-native meniscus junction; (c) anterior sector-native meniscus junction; (d) posterior horn internal control; and (e) anterior horn internal control. RESULTS: Three animals were euthanized at 39 ± 2.6 days post-surgery because of their knee condition. These animals had moderate Rodeo scores, low Ishida scores, and high Collagen I staining scores indicating moderately high fibrocartilaginous changes, mild or minimal healing and high collagen I content. Cartilage scores were low in the MFC and moderately high in the MTP, indicating mild MFC cartilage changes and moderately high MTP cartilage changes. Full-term (90 day) euthanized animals (n = 3) displayed improving Rodeo scores with mean scores of 3.3 and 3.6 at junctions (B) and (C), respectively. Ishida scores displayed similar improvements at all sectors. Collagen I staining revealed strong (grade 5) levels in all sections, with mean collagen I scores of 5, 5 and 4 for the peripheral (A), posterior (B) and anterior (C) junctions, respectively. Improved healing was observed at each segmental meniscus sector in terminally euthanized animals. CONCLUSIONS: Segmental meniscal allograft transplantation displayed partial healing to remnant meniscal tissue. Further study is needed to better delineate the time needed for complete healing and the joint-loading progression that may enhance it.

Medial meniscus grafting restores normal tibiofemoral contact pressures.

BACKGROUND: Tissue excision in the setting of a meniscal tear has been shown to dramatically increase peak contact stresses in the affected tibiofemoral joint compartment, leading to the development of degenerative changes and osteoarthritis. PURPOSE/HYPOTHESIS: The current in vitro study utilized a porcine model to evaluate the effectiveness of segmental medial meniscal grafting following partial meniscectomy. The study hypothesis was that the procedure would normalize medial tibofemoral joint compartment pressure magnitudes, areas, and locations relative to an intact meniscus. STUDY DESIGN: Controlled laboratory study. METHODS: Using pressure film, medial tibiofemoral joint compartment peak, and mean pressure magnitudes, peak pressure location and peak pressure area were determined using 12 potted, fresh frozen, porcine knee specimens. Data were collected at three different knee flexion angles (90°, 45°, and 0°) for three conditions: intact medial meniscus, following resection of the central third of the medial meniscus, and following segmental medial meniscal grafting. For each condition, the potted femur was positioned horizontally in a bench vise clamp, while a 20 pound (88.96 N) axial compression force was manually applied for a 60 s duration by the primary investigator through the base of the potted tibia using a digital force gauge. RESULTS: Loss of the central 1/3 of the medial meniscus resulted in significant increases in the mean and peak pressures of the medial tibiofemoral joint compartment and decreased peak pressure area. Segmental meniscal grafting of the central third defect closely recreated the contact pressures and loading areas of the native, intact medial meniscus. CONCLUSION: From a static, time zero biomechanical perspective, segmental medial meniscus grafting of a partially meniscectomized knee restored mean pressure, peak pressure, and mean peak contact pressure areas of the medial tibiofemoral joint compartment back to levels observed in the intact medial meniscus at different knee flexion angles. In-vivo analysis under dynamic conditions is necessary to verify the healing efficacy and ability of the healed segmental medial meniscal allograft to provide long-term knee joint homeostasis when confronted with dynamic shear, rotatory, and combined, higher magnitude physiologic loading forces.

Permanent knee sensorimotor system changes following ACL injury and surgery.

The cruciate ligaments are components of the knee capsuloligamentous system providing vital neurosensory and biomechanical function. Since most historical primary ACL repair attempts were unsuccessful, reconstruction has become the preferred surgery. However, an increased understanding of the efficacy of lesion-site scaffolding, innovative suturing methods and materials, and evolving use of biological healing mediators such as platelet-rich plasma and stem cells has prompted reconsideration of what was once believed to be impossible. A growing number of in vivo animal studies and prospective clinical studies are providing increasing support for this intervention. The significance of ACL repair rather than reconstruction is that it more likely preserves the native neurosensory system, entheses, and ACL footprints. Tissue preservation combined with restored biomechanical function increases the likelihood for premorbid neuromuscular control system and dynamic knee stability recovery. This recovery should increase the potential for more patients to safely return to sports at their desired intensity and frequency. This current concepts paper revisits cruciate ligament neurosensory and neurovascular anatomy from the perspective of knee capsuloligamentous system function. Peripheral and central nerve pathways and central cortical representation mapping are also discussed. Surgical restoration of a more physiologically sound knee joint may be essential to solving the osteoarthritis dilemma. Innovative rehabilitative strategies and outcome measurement methodologies using more holistic and clinically relevant measurements that closely link biomechanical and neurosensory characteristics of physiological ACL function are discussed. Greater consideration of task-specific patient physical function and psychobehavioral links should better delineate the true efficacy of all ACL surgical and non-surgical interventions. Level of evidence IV.

ACL double bundle linked cortical-aperture tibial fixation: a technical note.

INTRODUCTION: The purpose of this technical note is to describe the tibial fixation characteristics for an all-inside anatomic anterior cruciate ligament (ACL) reconstruction method that links extra-cortical button suspensory and aperture fixation replicating double bundle soft tissue graft function in single femoral and tibial sockets. MATERIALS AND METHODS: A 55° drill guide aligned guidewires in the ACL footprint center of 8 porcine tibiae (mean apparent bone mineral density = 1.15 g/cm(2)). A Flipcutter created 27 mm sockets and 15 mm guidewire channels. Advancement sutures seated porcine soft tissue graft-PEEK implants to achieve both socket aperture and extra-cortical button suspensory fixation. Potted specimens were loaded into a 6º of freedom clamp with the servohydraulic loading vector in direct socket alignment. Constructs were pre-loaded to 25 N, underwent 10 pre-conditioning cycles (0-50 N, 0.5 Hz), and 500 submaximal loading cycles (50-250 N, 1 Hz) prior to load to failure testing (20 mm/min). Mode of failure was recorded. Descriptive statistical analysis was performed. RESULTS: All specimens survived the biomechanical test protocol. Displacement during cyclic loading was 2.8 ± 0.9 mm, yield load was 475.2 ± 36 N, ultimate load at failure was 671.4 ± 98 N, stiffness was 127.5 ± 15 N/mm. The most common failure mode was suture pulling through the soft tissue graft. CONCLUSIONS: This ACL reconstruction method combines the high ultimate load to failure and low graft slippage of extra-cortical button suspensory fixation with the high stiffness of aperture fixation. Biomechanical test findings were comparable or better to previous reports for displacement during submaximal loading, ultimate failure load, and construct stiffness. Based on current understanding of soft tissue graft ACL reconstruction biomechanics, this fixation method should enhance graft-bone socket integration during healing, facilitate long-term graft survival, and improve patient outcomes. Clinical studies are needed to confirm in vivo efficacy.

All-Soft-Tissue Meniscus Allograft Transplantation With Circumferential Suture Tape Augmentation to Mitigate Hoop Stress and Promote Centralization.

Meniscus allograft transplantation (MAT) is a technically challenging procedure. Bone plugs, slot techniques, and all-soft-tissue fixation techniques have been described in the past. Each technique comes with advantages and disadvantages. Native menisci have circumferential collagen fibers to help resist hoop stress during loading cycles. Although hoop stress resistance is a known function of the menisci, its recreation in MAT has only been targeted indirectly through anatomic root placement. The authors describe the use of a high-tensile suture tape (i.e. InternalBrace) to promote centralization by directly mitigating hoop stresses through recreation of peripheral meniscus tensioning in MAT.

"Figure 8" single socket double bundle ACL technique.

Using single femoral and tibial tunnels, we describe a technique of anatomically recreating the anteromedial and posterolateral anterior cruciate ligament (ACL) bundles. Transtibial, flexible reamers are utilized to create a "Figure 8" notched tunnel thereby recreating the anatomic footprint of the femoral insertion of the ACL. Rotational control of the individual bundles is created via the notched tunnel and each bundle is tensioned to 80 N individually. Anatomic double bundle ACL reconstruction is created in a reproducible modified single-bundle technique without the inherent risks associated with drilling four tunnels.

Knee flexion angle is more important than guidewire type in preventing posterior femoral cortex blowout: a cadaveric study.

PURPOSE: This study compared femoral intraosseous "tunnel" length and distance from the posterior femoral cortex (PFC) when straight and flexible guidewires were drilled through an accessory anteromedial portal at 90° and 120° knee flexion. We had 2 study hypotheses: (1) 120° knee flexion would create longer femoral intraosseous tunnels than 90° knee flexion regardless of guidewire type and (2) 120° knee flexion would display a more consistent PFC blowout safety margin than 90° knee flexion regardless of guidewire type. METHODS: Straight and flexible guidewires were drilled at 90° and 120° flexion in 8 cadaveric knees. Guidewire intraosseous length and distance from the PFC were measured at both knee flexion angles. Two-way analysis of variance (guidewire type, knee flexion angle) and a Fisher exact test were used to compare group differences. RESULTS: Guidewire exit points at 120° knee flexion were located farther from the PFC than at 90° knee flexion regardless of whether flexible guidewires (19.0 ± 5.3 mm v 12.6 ± 3.3 mm) or straight guidewires (12.9 ± 4.5 mm v 5.0 ± 3.3 mm) were used (P < .0001). Straight guidewires drilled at 90° knee flexion were within 3 mm of the PFC in 4 of 8 specimens (50%) compared with 0 of 8 at 120° knee flexion (P = .038). Intraosseous guidewire length was greater at 120° knee flexion regardless of whether straight or flexible guidewires were used (P = .04). CONCLUSIONS: Flexible guidewires and a 120° knee flexion angle both decrease the likelihood of PFC blowout. A 120° knee flexion angle is more important to femoral tunnel length than guidewire type. Use of 120° knee flexion even when drilling flexible guidewires increases the safety margin needed to prevent PFC blowout. CLINICAL RELEVANCE: When knee flexion is limited, curved guides and flexible guidewires can help reduce PFC blowout risk and achieve longer tunnels.

Cyclic test comparison of all-inside device and inside-out sutures for radial meniscus lesion repair: an in vitro porcine model study.

PURPOSE: To compare biomechanical fixation and gapping characteristics of a new all-inside meniscus repair method for radial meniscus lesion repair versus conventional inside-out suture repair under submaximal cyclic loading and load-to-failure test conditions. METHODS: Fresh-frozen porcine tibiae with attached lateral menisci and joint capsules were harvested and stored for 48 hours at -20°C. After thawing for 12 hours, equivalent-size healthy specimens were randomly assigned to 2 groups of 8 specimens each. Standardized radial lesions were repaired with the Sequent device (ConMed Linvatec, Largo, FL) (group 1) or conventional inside-out suturing with No. 2-0 braided polyester suture (group 2). Repaired specimens were placed in custom clamps and mounted on a servohydraulic device. After a 2-N preload, specimens were cycled from 5 to 20 N (0.1 Hz), before undergoing 1,000 submaximal loading cycles between 5 and 20 N (0.5 Hz). A 40-second delay at 100, 500, and 1,000 cycles enabled digital photographs to be taken for gapping measurement determination. Specimens then underwent load-to-failure testing (12.5 mm/s). Fixation failure mode was documented. RESULTS: Group displacement did not differ after 1, 100, 500, and 1,000 submaximal loading cycles. Group peak gapping did not differ at 100, 500, and 1,000 submaximal loading cycles. Load at failure and displacement and stiffness during load-to-failure testing did not differ between groups. During load-to-failure testing, all-inside specimens failed by implant dislodgement from the meniscus periphery whereas the inside-out repaired specimens failed by suture rupture. CONCLUSIONS: Under controlled in vitro biomechanical test conditions, the all-inside device provided radial meniscus lesion fixation that was comparable, but not superior, to conventional inside-out suturing. CLINICAL RELEVANCE: The all-inside radial lateral meniscus lesion repair method may provide comparable fixation to conventional inside-out suturing without the need for additional incisions and their associated neurovascular injury risks.

Intratunnel versus extratunnel fixation of hamstring autograft for anterior cruciate ligament reconstruction.

PURPOSE: To determine which is more effective: intratunnel or extratunnel anterior cruciate ligament soft-tissue graft fixation. A secondary purpose was to determine whether groups displayed differing relations between objective International Knee Documentation Committee (IKDC) grade and the timing of full weight bearing (FWB), jogging/running, and return to sports. The study hypotheses were that intratunnel fixation would display a greater percentage of normal or nearly normal objective IKDC grades and enable earlier FWB, return to jogging/running, and return to sports. METHODS: We performed a systematic review of prospective, Studies with Level I or II evidence published from 2000 to 2011 with at least 2 years' follow-up that used interference screw hamstring autograft fixation (intratunnel group) or button, staple, or post hamstring autograft fixation (extratunnel group) for primary anterior cruciate ligament reconstruction. We also compared IKDC grades; Tegner and Lysholm scores; instrumented anterior laxity and pivot-shift test findings; timing of FWB, jogging/running, and return to sports; and modified Coleman Methodology Scores. RESULTS: The groups showed comparable modified Coleman Methodology Scores, objective IKDC grades, Lysholm and Tegner scores, instrumented anterior laxity and pivot-shift test findings, and return-to-sports timing. The intratunnel group displayed earlier FWB and jogging/running; however, return-to-sports timing did not differ between groups. Early FWB and the percentage of patients with normal or nearly normal objective IKDC grades were directly related for the extratunnel group. CONCLUSIONS: Patients who received intratunnel fixation were released earlier to FWB and jogging/running, supporting the study hypotheses. Groups did not differ in return-to-sports timing or objective IKDC grades, not supporting the study hypotheses. Early FWB in the extratunnel group was related to a greater percentage of patients having normal or nearly normal objective IKDC grades. Return-to-sports timing and having a normal objective IKDC grade were related in both groups; however, this relation was stronger with intratunnel fixation. LEVEL OF EVIDENCE: Level II, systematic review of Level I and II studies.

A new technique for arthroscopic meniscus transplant using soft tissue fixation and anatomical meniscal root reinsertion.

UNLABELLED: Allograft meniscus transplant is considered as a treatment option for meniscus-deficient patients to provide pain relief and decrease contact stress. This procedure is now considered as safe and reliable for the treatment for knee pain after total menisectomy. This is a new technique that has been developed for arthroscopic meniscus transplant with no bone blocks. It anatomically recreates the meniscus-tibial insertions and provides aperture fixation of the meniscus horns. It is an alternative to the established bone block meniscus transplant technique and is less surgically invasive. LEVEL OF EVIDENCE: V.

Collagen meniscus implantation: a systematic review including rehabilitation and return to sports activity.

PURPOSE: To determine collagen meniscus implant (CMI) efficacy for improving patient function, symptoms, and activity level. Study methodologies, rehabilitation, and return to sports guidelines were also reviewed. METHODS: MedLine, EMBASE, CINAHL, Life Science Citations, and Cochrane Central Register of Controlled Trials databases were searched from January 1995-May 2011 using the term collagen meniscal or meniscus implant. Only human studies with English language abstracts that reported patient outcomes were included. Modified Coleman Methodology criteria were used to score research quality. RESULTS: Eleven studies with 520 subjects (men = 428; women = 92; 17.7% women) of 38.2 ± 3.7 years of age met the inclusion criteria. Of these subjects, 321 (men = 263, women = 58; 18.1% women) received a CMI. Based primarily on Lysholm Knee Score, Tegner Activity Scale, pain scales and self-assessment measurements knee function, symptoms, and activity level generally improved by 46.6 ± 39.9 months post-surgery. Rehabilitation was described in 9/11 (81.8%) studies and four released patients to full activities at 6 months post-surgery. No study described how advanced rehabilitation or function testing contributed to return to activity decision-making. Research quality was generally low (67.1 ± 18.6) with widely ranging (29-97) scores. Reduced CMI size at last follow-up was reported in 6/11 (54.5%) studies, but the significance of this finding is unknown. CONCLUSIONS: Knee function, symptoms, and activity level generally improved following CMI use, but poor research report quality was common. Additional well-designed long-term prospective studies are needed to better determine knee osteoarthrosis prevention efficacy and appropriate patient selection.

Consideration of growth factors and bio-scaffolds for treatment of combined grade II MCL and ACL injury.

The literature suggests that a Grade II medial collateral ligament (MCL) injury in combination with anterior cruciate ligament (ACL) injury will heal naturally and not compromise patient outcome following ACL reconstruction. Evidence based on bone-patella tendon-bone autograft use is stronger than evidence supporting anatomically placed soft tissue graft use. Current ACL reconstruction practices make greater use of soft tissue grafts, differing fixation methods, and anatomically lower placement on the inner wall of the lateral femoral condyle. Anatomical graft placement aligns the femoral bone tunnel more directly with valgus knee loading forces. Differences in the soft tissue graft-bone tunnel integration and ligamentization timetable following ACL reconstruction also increase concerns regarding residual Grade II MCL laxity and functional deficiency during accelerated functional rehabilitation. MCL dysfunction may increase susceptibility to early ACL graft slippage, elongation, outright failure, and medial femoral condyle lift-off with valgus knee loading. This concept paper discusses the potential role of growth factors and bio-scaffolds for improving Grade II MCL injury healing and mechanical integrity when the injury occurs in combination with an ACL injury that is reconstructed with a soft tissue graft and an anatomical surgical approach.

The posteromedial knee arthroscopy portal: a cadaveric study defining a safety zone for portal placement.

PURPOSE: To define a neurovascular safety zone for proper placement of at least 2 posteromedial (PM) portals and to describe a safe intra-articular entrance point based on the location of the PM capsular folds. METHODS: Arthroscopy was performed on 10 fresh-frozen cadaveric knees. With the knee flexed 90°, PM portals were created under direct visualization with a 70° arthroscope. The anatomic soft spot between the PM edges of the femoral condyle and the proximal tibia was palpated, and 18-gauge spinal needles were inserted into the joint followed by 5.0-mm cannulas. The PM capsular folds were used to guide portal locations. Four portals (A, B, C, and D) were created in each of the first 3 knees. Portal position was described in relation to the soft spot: through the soft spot (A), 1 cm superior (B), 1 cm posterior (C), and 1 cm inferior (D). Dissection was performed along the path of the cannulas. RESULTS: In the first 3 knees, the most inferior portal (D) always overlapped the course of the saphenous nerve, and the posterior portal (C) always pierced the gastrocnemius musculotendinous junction. Therefore these portals were eliminated from further study for safety reasons, and in the final 7 knees, we studied only the remaining 2 portal placements (A and B). Portals A and B were found to be the safest, with at least 1.5 cm of clearance between the portals and the saphenous nerve in all specimens. CONCLUSIONS: At least 2 PM portals can be safely placed in the knee. The soft spot is an appropriate landmark to ensure safe portal entry. The PM capsular folds can help guide intra-articular placement so that damage to surrounding structures can be avoided. CLINICAL RELEVANCE: We believe that 2 portals would be beneficial when performing complex arthroscopic procedures involving the PM compartment of the knee.

Lower extremity compensatory neuromuscular and biomechanical adaptations 2 to 11 years after anterior cruciate ligament reconstruction.

PURPOSE: To determine whether compensatory neuromuscular and biomechanical adaptations exist after successful anterior cruciate ligament reconstruction and rehabilitation. METHODS: Seventy subjects, 5.3 +/- 3 years after surgery, participated in this study. Sagittal-plane lower extremity kinematic, gluteus maximus, vastus medialis, medial hamstring, and gastrocnemius electromyography (EMG) and vertical ground reaction force data were collected during single-leg countermovement jump (CMJ) performance. RESULTS: Women had lower propulsive and landing forces, lower CMJ heights, less hip and knee flexion, and greater angular hip, knee, and ankle velocities than men (P < or = .014). The involved lower extremity of men and women had decreased landing forces (P = .008). During propulsion, men and women had increased involved-lower extremity gluteus maximus (P < .0001) and decreased vastus medialis (P = .013) EMG amplitudes, whereas women had bilaterally increased gastrocnemius EMG amplitudes compared with men (P = .003). During propulsion, men had longer gluteus maximus and vastus medialis EMG durations than women (P < .0001). During landing, both men and women had increased gluteus maximus EMG amplitudes at the involved lower extremity (P < .0001). Women had increased vastus medialis (P = .01) and gastrocnemius (P < .0001) EMG amplitudes compared with men. During landing, men had longer gluteus maximus (P = .004), vastus medialis (P = .012), and gastrocnemius (P = .007) EMG durations than women and the involved-lower extremity vastus medialis EMG durations of both men and women were shorter than at the noninvolved lower extremity (P = .011). CONCLUSIONS: Decreased involved-lower extremity landing forces, decreased vastus medialis activation, and increased gluteus maximus and gastrocnemius activation suggest a protective mechanism to minimize knee loads that increase anterior translatory knee forces during single-leg jumping. Women showed more balanced gluteus maximus, vastus medialis, and gastrocnemius contributions to dynamic knee stability than men during CMJ landings but used shorter activation durations. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Osseous deficits after anterior cruciate ligament injury and reconstruction: a systematic literature review with suggestions to improve osseous homeostasis.

PURPOSE: This systematic review was performed to improve our understanding of the current evidence regarding the influence of anterior cruciate ligament (ACL) injury and reconstruction on involved lower extremity apparent bone mineral density, bone content, or bone area mass (bone integrity). METHODS: Two independent reviewers performed a Medline search from 1966 to January 2010 using the terms "anterior cruciate ligament" or "ACL" combined with "wound" or "injury" and "bone density" or "osteoporosis." Study inclusion criteria were English-language human studies. Reference sections of selected studies were also reviewed. RESULTS: Ten studies were identified that met our inclusion criteria. Eight studies performed ACL reconstruction with bone-patellar tendon-bone autografts and interference screw fixation. One study performed ACL reconstruction by use of Achilles tendon allografts with interference screw and staple fixation. Two ACL injury studies either did not involve ACL reconstruction or attempted primary repair with sutures. All studies reported varying levels of decreased bone mineral density, bone content, or bone area mass (bone integrity) at the involved lower extremity after ACL injury that did not return to premorbid levels even with ACL reconstruction and rehabilitation. Sites of reduced bone integrity included the proximal and distal femur, proximal tibia, patella, and calcaneus. Bone loss was increased with limited weight bearing and prolonged disuse or immobilization; however, significant improvements were not observed with accelerated rehabilitation. Some studies reported relations between Lysholm, Tegner, International Knee Documentation Committee survey, or function scores and bone integrity, whereas others reported no or poor relations. CONCLUSIONS: Involved lower extremity bone integrity is decreased after ACL injury. Current evidence suggests that premorbid bone integrity is not re-established after ACL reconstruction even when accelerated rehabilitation is performed. Recommendations to improve osseous homeostasis and bone health after ACL injury and reconstruction are provided.

Biomechanical comparison of screw-in suture anchor-suture combinations used for Bankart repair.

INTRODUCTION: Bankart repair laxity may contribute to pathologic joint instability. This biomechanical study compared two screw-in suture anchor-suture combinations under tensile loads. METHODS: Twelve pairs of scapulae were implanted with either a 3 mm diameter, 14 mm long poly-L/D-lactide suture anchor with a suture eyelet (Group 1) or a 3.1 mm diameter, 11 mm long polylactide suture anchor with a molded eyelet (Group 2). Constructs were cyclically loaded between 25 and 50 N with a 25 N load increase every 25 cycles. RESULTS: Group 2 displayed greater displacement at failure, had more specimens with > or =2 mm displacement by the 50 N interval (P = 0.014), and had displaced more by 100 N (P < or = 0.046). Group 1 displayed a stronger load-displacement at failure relationship than Group 2 (r (2) = 0.67 vs. r (2) = 0.37). CONCLUSION: Construct differences may influence decisions regarding the required number of suture anchor-suture loops, the rehabilitation timetable, and the timing of return to unrestricted activities.