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Background: Vascular CD34+ cells in anterior cruciate ligament (ACL) tissue have the potential for high proliferation and multilineage differentiation that can accelerate tendon-bone healing. While patient characteristics, such as age, can affect tendon-bone healing, the influence of elapsed time after injury on the healing process is unclear. Hypothesis: Cells obtained during the early phase after injury will exhibit a greater tendon-bone healing potential compared with chronic phase counterparts when applied to an immunodeficient rat model of ACL reconstruction. Study Design: Controlled laboratory study. Methods: Adult human ACL-ruptured tissue was harvested from patients undergoing arthroscopic primary ACL reconstruction and classified into 2 groups based on the time elapsed between injury and surgery: (1) early group (≤3 months from injury) and (2) chronic group (>3 months from injury). In addition, 76 ten-week-old female immunodeficient rats underwent ACL reconstruction, followed by intracapsular administration of one of the following: (1) ACL-derived cells from the early group (n = 5), (2) ACL-derived cells from the chronic group (n = 5), or (3) phosphate-buffered saline (PBS) only (n = 5). During the 8 weeks after surgery, histological (weeks 2, 4, 8), immunohistochemical (week 2), radiographic (weeks 0, 2, 4, 8), and biomechanical (week 8) analyses were performed to evaluate tendon-bone healing. Results: In the early group, the histological evaluation showed early healing, induction of endochondral ossification–like integration, and mature bone ingrowth. Micro–computed tomography showed that the tibial bone tunnels at week 4 and week 8 were significantly reduced in the early group compared with those in the chronic group and PBS group (P < .05). Moreover, biomechanical tensile strength was significantly greater in the early group than in the other groups (P < .05). An accelerated healing potential in the early group was further demonstrated by the enhancement of intrinsic angiogenesis/osteogenesis and human-derived vasculogenesis/osteogenesis. Conclusion: Compared with human ACL-derived cells obtained during the chronic phase, cells obtained during the early phase after injury have a greater tendon-bone healing potential when used in an immunodeficient rat model of ACL reconstruction. Clinical Relevance: During ACL reconstruction surgery, transplanting ACL remnant tissue in the early phase after injury could accelerate and enhance tendon-bone healing. [ABSTRACT FROM AUTHOR]

Background: Remnant-preserved anterior cruciate ligament (ACL) reconstruction was introduced to improve clinical outcomes and biological healing. However, the effects of remnant preservation and the influence of the delay from injury until reconstruction on the outcomes of this technique are still uncertain. Purpose/Hypothesis: The purposes of this study were to evaluate whether remnant preservation improved the clinical outcomes and graft incorporation of ACL reconstruction and to examine the influence of the delay between ACL injury and reconstruction on the usefulness of remnant preservation. We hypothesized that remnant preservation improves clinical results and accelerates graft incorporation and that its effect is dependent on the delay between ACL injury and reconstruction. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 151 consecutive patients who underwent double-bundle ACL reconstruction using a semitendinosus graft were enrolled in this study: 74 knees underwent ACL reconstruction without a remnant (or the remnant was <25% of the intra-articular portion of the graft; NR group), while 77 knees underwent ACL reconstruction with remnant preservation (RP group). These were divided into 4 subgroups based on the time from injury to surgery: phase 1 was <3 weeks (n = 24), phase 2 was 3 to less than 8 weeks (n = 70), phase 3 was 8 to 20 weeks (n = 32), and phase 4 was >20 weeks (n = 25). Clinical measurements, including KT-1000 arthrometer side-to-side anterior tibial translation measurements, were assessed at 3, 6, 12, and 24 months after reconstruction. Magnetic resonance imaging evaluations of graft maturation and graft-tunnel integration of the anteromedial and posterolateral bundles were assessed at 3, 6, and 12 months after reconstruction. Results: There was no difference in side-to-side anterior tibial translation between the NR and RP groups. There was also no difference in graft maturation between the 2 groups. Furthermore, the time from ACL injury until reconstruction did not affect graft maturation, except in the case of very long delays before reconstruction (phase 4). Graft-tunnel integration was significantly increased in both groups in a time-dependent manner. However, there was no difference between the NR and RP groups. Conclusion: Remnant preservation did not improve knee stability at 2 years after ACL reconstruction. Furthermore, remnant preservation did not accelerate graft incorporation, especially during the acute and subacute injury phases. [ABSTRACT FROM AUTHOR]

Background: The anterior cruciate ligament (ACL) does not heal spontaneously after injury, and ACL patients of different ages respond differently to treatment. Although ACL-derived CD34-positive cells contribute to bone-tendon healing after ACL reconstruction, the relationship between the healing potential of ACL-derived cells and a patient's age is unknown. Hypothesis: ACL-derived cells from young patients will have a greater effect on the maturation of bone-tendon integration in an immunodeficient rat model of ACL reconstruction compared with cells derived from older patients. Study Design: Controlled laboratory study. Methods: Sixty 10-week-old female immunodeficient rats underwent ACL reconstruction (using the autologous flexor digitorum longus tendon as a graft) followed by intracapsular administration of ACL-derived cells from patients aged 10 to 19 years (younger group) or patients aged 30 to 39 years (older group), or they were given phosphate-buffered saline (PBS; PBS group). Histologic, radiographic, and biomechanical examinations were performed 2 to 8 weeks after surgery. In addition, intrinsic and human cell– derived angiogenesis and osteogenesis were examined by immunohistochemistry. Results: In the younger group, histologic assessment demonstrated early bone-tendon healing, which induced endochondral ossification-like integration. Micro–computed tomography showed a statistically significant reduction in the area of tibial bone tunnel in the younger group (week 4, 20.0% ± 11.2% reduction; week 8, 25.7% ± 5.6% reduction) compared with the older group (week 4, 1.8% ± 3.0% reduction; week 8, 4.0% ± 5.9% reduction) and the PBS group (week 4, -0.5% ± 3.2% reduction; week 8, 3.3% ± 5.2% reduction) (week 4, P<.05; week 8, P<.01). Failure loads during tensile testing demonstrated a significantly higher ultimate load to failure in the younger group (17.52 ± 4.01 N) compared with the older (8.05 ± 2.91 N) and PBS (7.01 ± 3.16 N) groups (P<.05), and isolectin B4 and rat osteocalcin immunostaining indicated enhanced intrinsic angiogenesis and osteogenesis in the younger group. There was no statistically significant difference in the results of radiographic and biomechanical examinations between the older and PBS groups. Double immunohistochemistry for human-specific endothelial cell and osteoblast markers demonstrated a greater ability of differentiation into endothelial cells and osteoblasts in the younger group. Conclusion: ACL-derived cells from younger patients enhanced early bone-tendon healing in an immunodeficient rat model of ACL reconstruction. Clinical Relevance: Surgeons should consider a patient's age when performing ACL reconstruction with remnant preservation or ruptured tissue incorporation, as this can predict healing ability. [ABSTRACT FROM AUTHOR]

The article discusses research which investigated osteochondritis dissecans (OCD) prevalence in adolescent baseball players. Topics explored include the elbow disability associated with OCD of the humeral capitellum, symptoms and factors that contribute to OCD such as microtrauma, the results of the ultrasonographic examinations performed on participating patients, and the need to diagnose OCD early to avoid treatment difficulties.

The article presents research which focused on the use of 3-dimensional motion analysis platform to measure the glenoid track. Topics covered include the description of Hill-Sachs lesion as an injury linked with instability of anterior glenohumeral rim as well as application of magnetic resonance imaging (MRI) in the study. Also mentioned are participation of 30 healthy volunteers in this research.

The article presents research which examined the age-related differences in cells derived from the anterior cruciate ligament (ACL). Topics covered include the description of ACL tissues in adolescent and younger patients as well as collection of ACL remnants from 28 patients. Also mentioned is the need for surgeons to consider the age of patients when assessing healing potential of those with ACL injuries.

The article presents a study which investigated the ideal matching patterns of articular surface profiles of donor and recipient sites for autogenous osteochondral grafting of the femur of the knee through the use of three-dimensional laser scanning technique. It claims that the grafting method is broadly used as treatment for focal osteochondral defects. In the study, the FastSCAN Cobra three-dimensional (3D) laser scanner from Polhemus was used to profile the knee.

Background:A disadvantage of pivot-shift maneuvers is that the examiner has to subjectively evaluate the degree of pivot shift observed. It is unknown whether the various maneuvers are biomechanically identical.Purpose:To compare biomechanical features of 3 clinical maneuvers for the anterior cruciate ligament (ACL)–deficient knee: the pivot-shift test, the jerk test, and the N-test.Study Design:Controlled laboratory study.Methods:A total of 28 patients with an isolated ACL injury were examined by use of 3 pivot-shift maneuvers (pivot-shift test, jerk test, and N-test). An electromagnetic sensor system was used to evaluate the 3-dimensional knee kinematics of each patient’s injured and uninjured knees during each maneuver. Peak coupled anterior tibial translation (pCAT) and maximal acceleration of posterior translation (APT) were measured relative to results during a flexion-extension motion in each test.Results:The pCAT of the pivot-shift test was significantly greater than that of both the jerk test and the N-test (P = .0020 and P < .0001, respectively); there was no statistical difference in pCAT between the jerk test and the N-test. The APT of the N-test was significantly greater than that of both the pivot-shift test and the jerk test (P < .0001), while there was no statistical difference between the pivot-shift and the jerk tests. There was no correlation between pCAT and APT in each test.Conclusion:The pivot-shift test, jerk test, and N-test have different biomechanical characteristics to induce the pivot-shift phenomenon in the ACL-deficient knee. The pivot-shift test produced the largest side-to-side difference in pCAT, whereas the N-test provoked the largest side-to-side difference in APT.Clinical Relevance:The biomechanical differences in pivot-shift maneuvers are caused by technical differences, and clinicians should understand these biomechanical differences while practicing the maneuvers. The electromagnetic sensor system is clinically useful for quantifying the pivot-shift phenomenon. [ABSTRACT FROM AUTHOR]

The article presents a study on articular cartilage degeneration which can develop after anterior cruciate ligament reconstruction (ACLR). It focuses on risk factors in the early postoperative period. The T1ρ spin-lattice relaxation in the rotating frame magnetic resonance imaging is described. The baseline T1ρ value of the medial femoral condyle (MFC) and lateral FC (LFC) was higher in patients with cartilage lesions.

The article presents a whole-cadaver study on the function of acromioclavicular (AC) and coracoclavicular (CC) ligaments in shoulder motion. It evaluates the shoulder girdle motion relative to the thorax of 14 shoulders from 8 whole cadavers after sequential sectioning of the AC and CC ligaments. It highlights that kinematic changes could be the main reason for pain and dysfunction in the shoulder with AC joint dislocation, and hence, certain patients may require surgical reconstruction.

Background: The well-known suture technique configurations used for hamstring tendon autograft preparation in anterior cruciate ligament (ACL) reconstruction are the Krackow locking stitch and nonlocking stitch, such as a baseball stitch and a whipstitch. However, there are few data in the literature regarding biomechanical comparisons of suture techniques. Purpose: The purpose of this study was to determine the properties of several current techniques of tendon graft suture employed in ACL reconstruction. Study Design: Controlled laboratory study. Methods: Forty-two fresh-frozen porcine flexor digitorum tendons were used. Three stitch configurations (Krackow stitch [group K], baseball stitch [group B], and whipstitch [group W]) were assessed with varying suture throws (6 throws, group36; 10 throws, group310) using No. 5 Ethibond sutures. Each group was tested at 1500 loading cycles between 50 and 200 N. After loading cycles, the surviving tendons underwent a load-to-failure test. Results: During the loading cycles, 3 of 7 specimens in group B×6 and all specimens in group W×6 failed by suture pullout. Four of 7 specimens in group B×10 and all specimens in group W×10 showed partial tearing of the tendon. Elongation of group B×10 and group W×10 showed significantly greater elongation than other groups (P < .05). Maximum loads at failure showed significant differences between group K and the other groups (K×6, 436 ± 52 N; K×10, 419 ± 34 N; P < .05). Most specimens failed by rupture of the suture thread in group K. Pullout of the suture from the tendon was observed most in groups B and W. Conclusion: The Krackow stitch was superior to other stitch methods. There was, however, no significant effect of the number of throws on the holding strength. Clinical Relevance: The Krackow stitch could prevent suture slippage by a locking mechanism. The whipstitch is not suitable for clinical application even with an increased number of throws. [ABSTRACT FROM AUTHOR]

Background: Rotator cuff regeneration using tissue engineering techniques is a challenging treatment in elderly patients with irreparable rotator cuff tears.Hypothesis: A polyglycolic acid sheet scaffold with seeded mesenchymal stem cells (MSCs) may enhance the expression of type I collagen products and increase the mechanical strength of the regenerated tendon in vivo.Study Design: Controlled laboratory study.Methods: A surgically created defect of infraspinatus tendons of rabbits was reconstructed with 2 different materials, a polyglycolic acid (PGA) sheet alone (PGA group) (n = 34) and a PGA sheet seeded with autologously cultured MSCs (MSC group) (n = 34). The authors created a tendon defect model without embedding any graft as the control model (control group) (n = 34). The rabbits were sacrificed at 4, 8, and 16 weeks after the operation and then were histologically evaluated. The rabbits were also biomechanically evaluated by measuring the ultimate failure loads and Young’s modulus at 4 and 16 weeks following implantation.Results: In the MSC group, the fibrocartilage layers and Sharpey fibers were found regularly in the insertion site at 8 weeks compared with the PGA group. In control group, thin membranes with many fibroblasts arranged in an irregular pattern linked the end of the torn cuff to the bone without any Sharpey fibers and type I collagen. A large volume of type I collagen was found in comparison with type III collagen at 16 weeks in the MSC group, whereas type III collagen was more prevalent than type I in the PGA group. The tendon maturing score in the MSC group had higher values than the PGA and control groups at 8 and 16 weeks (mean values were 21.0 ± 0.89, 24.0 ± 2.53 in the MSC group; 16.7 ± 2.25, 21.3 ± 2.42 in the PGA group; and 10.2 ± 0.98, 12.2 ± 1.72 in the control group, respectively) (P < .05). The results of the mechanical analysis revealed that the regenerated tendons in the MSC group had better tensile strength than in the PGA and control groups at 16 weeks (mean values were 3.04 ± 0.54 in the MSC group, 2.38 ± 0.63 in the PGA group, and 1.58 ± 0.13 in the control group) (P < .05).Conclusion: Bone marrow–derived MSCs were able to regenerate tendon-bone insertions and the tendon belly, including the production of type I collagen, and increased the mechanical strength of the regenerated rotator cuff tendon.Clinical Relevance: Rotator cuff regeneration using MSCs is a promising treatment for massive rotator cuff defects. [ABSTRACT FROM PUBLISHER]

Background: To theoretically minimize complications of osteochondral graft harvest from the knee, grafts should be obtained from the site of lowest stress distribution across the joint.Hypothesis: Long-term stress distribution over the patellofemoral (PF) joint surface is not equal in athletes.Study Design: Cross-sectional study; Level of evidence, 3.Methods: Measurement of subchondral bone density can determine long-term resultant stress acting on an articular surface in living joints. Our analysis was performed using computed tomography (CT) image data obtained from bilateral knees of 10 college baseball fielders (fielder group) and 10 college baseball pitchers (pitcher group) and 2 control groups, including 10 college soccer players (soccer group) and 10 nonathletes (nonathlete group). The distribution pattern of subchondral bone density throughout the articular surface of the PF joint was assessed using the CT osteoabsorptiometry method. The quantitative analysis focused on the location of the low-density area at the articular surface to assess potential osteochondral donor sites.Results: All participants in the pitcher and fielder groups demonstrated a low-density area widely distributed in the proximal part of the lateral trochlea. On the other hand, a high-density area was located in the distal part of the lateral notch, of the medial notch, and of the medial trochlea. No apparent differences in the distribution pattern were found between the baseball groups and the control groups.Conclusion: Our analysis, based on CT osteoabsorptiometry, indicates that the proximal lateral trochlea of the distal femur has the highest percentage area of low bone density at the PF joint level in donor knees of baseball players, soccer players, and nonathlete controls.Clinical Relevance: From a biomechanical viewpoint, the proximal lateral trochlea is the optimal site for harvesting osteochondral grafts in performing mosaicplasty for baseball players. This selection for the donor site may minimize postoperative PF joint symptoms. [ABSTRACT FROM PUBLISHER]

Background: One of the main differences affecting outcome between single-bundle and double-bundle anterior cruciate ligament (ACL) reconstructions may be graft fixation angles and initial force settings; however, there has been little research to investigate these effects in either technique.Hypothesis: Anteroposterior and rotational knee laxities will be less in double-bundle ACL reconstructions than single-bundle reconstructions, and different graft fixation angles affect knee kinematics and pivot-shift phenomenon in double-bundle ACL reconstructions.Study Design: Controlled laboratory study.Methods: Eleven patients who underwent double-bundle ACL reconstruction were included in this study. The anteromedial bundle (AMB) and the posterolateral bundle (PLB) were provisionally fixed to a graft tensioning system during surgery. The graft fixation settings were as follows: (1) AMB only at 20° (A20), (2) PLB only at 20° (P20), (3) AMB at 20° and PLB at 0° (A20P0), (4) AMB at 20° and PLB at 20° (A20P20), and (5) AMB at 20° and PLB at 45° (A20P45). All the grafts were tensioned at a constant stress level. Anterior tibial translation (ATT), internal rotation (IR), and external rotation (ER) at 30° and 90° of knee flexion applied with manual maximum load were measured before graft insertion and in each setting using a navigation system. A pivot-shift test was also evaluated manually with modified International Knee Documentation Committee criteria in each setting.Results: A20 was less constrained than A20P20 and A20P45 in ATT at 30° and less constrained than A20P45 in IR at 30°. P20 was less constrained than any other settings in ATT at 30° and less constrained than A20P45 in IR at 30°. A20P0 was less constrained than A20P45 in IR at 30° and in ER at 30°. Grade 1 pivot-shift phenomenon persisted in 8 cases in P20, in 4 cases in A20, and in 3 cases in A20P0, whereas no case showed a positive pivot-shift result in A20P20 and A20P45.Conclusion: In this in vivo laboratory model, double-bundle ACL reconstruction with fixation of AMB at 20° and PLB at 20° or 45° restored better stability than single AMB or single PLB reconstruction in which the graft was of smaller size.Clinical Relevance: In double-bundle ACL reconstruction, fixation of the PLB at 0° might be looser and function worse compared with that of PLB at 20° or 45° when the AMB is fixed at 20°, with the individual variability that should lead to caution until it can be better assessed by surgeons. [ABSTRACT FROM PUBLISHER]

Background: A sheep or goat anterior cruciate ligament (ACL) reconstruction model with the semitendinosus tendon autograft has not as of yet been established.Hypothesis: The semitendinosus tendon graft may be necrotized after ACL reconstruction until 12 weeks. Structural properties of the femur-graft-tibia complex may not be restored to the normal ACL level even at 12 months after surgery.Study Design: Controlled laboratory study.Methods: Thirty-eight mature sheep were used. In each animal, the right knee underwent ACL reconstruction using the semitendinosus tendon autograft. Two of them were not tested because of pneumonia. Twenty of 36 sheep were used for biomechanical evaluations. Five randomly selected animals were sacrificed at 0, 12, 24, or 52 weeks after surgery. In each animal, both the knees were harvested, and the left knee was used to obtain the control data. The remaining 16 sheep were used for histological evaluation. Two or 3 randomly selected animals were sacrificed at 0, 2, 6, 12, 24, or 52 weeks after surgery.Results: The tendon graft was predominantly acellular at 2 weeks. Although cell infiltration increased at 6 weeks, the core portion remained necrotic even at 12 weeks. At 24 and 52 weeks, the necrotic lesion disappeared in the core portion. In each period, the anteroposterior translation of the reconstructed knee remained significantly greater than that of the control (P < .0001). At 52 weeks, the maximum load of the femur-graft-tibia complex was significantly lower than that of the femur-ACL-tibia complex (P < .0001), although there was no significant difference in the cell density, the tissue dimensions, the stiffness, and the elongation at failure between the 2 complexes.Conclusion: The sheep ACL reconstruction model showed predominant intrinsic fibroblast necrosis in the tendon autograft until 12 weeks. Although the structural properties of the femur-graft-tibia complex gradually improved, they were not completely restored to the femur-ACL-tibia complex level even at 52 weeks.Clinical Relevance: Remodeling of the semitendinosus tendon autograft after ACL reconstruction is not different from that of the bone-tendon-bone graft. This study has suggested that vigorous activity should not be permitted for patients in the early periods after ACL reconstruction using semitendinosus tendon autografts, which are necrotized and weakened after surgery. [ABSTRACT FROM PUBLISHER]

Background: The alterations in blood flow after rotator cuff repair remain unclear. Visualization of vascular patterns could clarify basic and clinical investigations.Purpose: To assess longitudinal blood flow inside the repaired cuff and the surrounding tissue after rotator cuff repair, using contrast-enhanced ultrasonography.Study Design: Descriptive laboratory study.Methods: Fifteen patients (7 men and 8 women; mean age, 65.0 ± 9.8 years) consented to participate. The patients underwent an ultrasound scan before and 1, 2, and 3 months after surgery. Enhanced ultrasound images were recorded for 1 minute after intravenous injection of contrast reagent. Four regions of interest inside the cuff and 2 regions in the anchor hole and subacromial bursa were superimposed on the obtained images. Calculated areas under the time-intensity curves were expressed in acoustic units (AU).Results: We found area-dependent differences in patterns of alteration and magnitude of blood flow inside the repaired cuff and peritendinous tissues. Vascularity in the articular distal and bursal distal region of the repaired cuff at 1 month postoperatively increased significantly compared with that at the preoperative baseline (76 vs 5 AU, P = .0037; 92 vs 7 AU, P = .043). The vascularity peaked at 1 month after surgery in the bursal area within the cuff but at 2 months in the articular area. The vascularity in the articular proximal region of the repaired cuff was significantly lower than that in the bursal proximal (P = .0046), bursal distal (P = .0183), and articular distal regions (P = .0163) 1 month after surgery.Conclusion: Enhancement patterns in intratendinous tissue increased at 1 or 2 months postoperatively and decreased at 3 months. We found area-dependent differences in enhancement patterns inside the repaired cuff and peritendinous tissue.Clinical Relevance: Visualization of vascularization using contrast-enhanced ultrasound could help in deciding on an appropriate repair technique or on the form of postoperative rehabilitation after rotator cuff repair. [ABSTRACT FROM AUTHOR]

Background: Although previous biomechanical research has demonstrated the superiority of the suture-bridge rotator cuff repair over double-row repair from a mechanical point of view, no articles have described the structural and functional outcomes of this type of procedure.Hypothesis: The structural and functional outcomes after arthroscopic rotator cuff repair may be different between the single-row, double-row, and combined double-row and suture-bridge (compression double-row) techniques.Study Design: Cohort study; Level of evidence, 3.Methods: There were 206 shoulders in 201 patients with full-thickness rotator cuff tears that underwent arthroscopic rotator cuff repair. Eleven patients were lost to follow-up. Sixty-five shoulders were repaired using the single-row, 23 shoulders using the double-row, and 107 shoulders using the compression double-row techniques. Clinical outcomes were evaluated at an average of 38.5 months (range, 24-74 months) after rotator cuff repair. Postoperative cuff integrity was determined using Sugaya’s classification of magnetic resonance imaging (MRI).Results: The retear rates after arthroscopic rotator cuff repair were 10.8%, 26.1%, and 4.7%, respectively, for the single-row, double-row, and compression double-row techniques. In the subcategory of large and massive rotator cuff tears, the retear rate in the compression double-row group (3 of 40 shoulders, 7.5%) was significantly less than those in the single-row group (5 of 8 shoulders, 62.5%, P < .001) and the double-row group (5 of 12 shoulders, 41.7%, P < .01). Postoperative clinical outcomes in patients with a retear were significantly lower than those in patients without a retear for all 3 techniques.Conclusion: The additional suture bridges decreased the retear rate for large and massive tears. The combination of the double-row and suture-bridge techniques, which had the lowest rate of postoperative retear, is an effective option for arthroscopic repair of the rotator cuff tendons because the postoperative functional outcome in patients with a retear is inferior to that without retear. [ABSTRACT FROM PUBLISHER]

Background: Suture-button fixation for tibiofibular syndesmosis injuries is a relatively new surgical technique thought to provide semirigid dynamic stabilization. However, adequate information is still not available and there are controversies as to whether it provides enough fixation for syndesmosis injuries.Hypothesis: Optimally directed suture-button fixation brings physiologic dynamic stabilization of the ankle syndesmosis.Study Design: Controlled laboratory study.Methods: Stabilization of the ankle syndesmosis fixed by a suture-button construct was examined using 6 normal fresh-frozen cadaver legs. After initial tests of intact and injured models, suture-button fixation and screw surgical techniques were performed sequentially for each specimen, with single suture-button fixation, double suture-button fixation, anatomic suture-button fixation, and metal screw. Anterior and medial traction forces, as well as external rotation force, were applied to the tibia; the diastasis of the syndesmosis and the rotational angle of the fibula related to the tibia were measured using a magnetic tracking system.Results: Each traction and rotation force significantly increased the diastasis and fibular rotational angles in the created injury models. With single fixation, the diastases increased significantly compared with the intact model with an anterior traction force (P < .001), a medial traction force (P = .005), and an external rotation force (P = .015). The fibular rotational angles increased significantly with a medial traction force (P = .005) and an external rotation force (P < .001). With double fixation, the diastases increased significantly with a medial traction force (P = .004) and an external rotation force (P = .012). The fibular rotational angles increased significantly with a medial traction force (P = .035) and an external rotation force (P = .002). With anatomic fixation, there were no significant differences compared with the intact model. With the metal screw, the diastases decreased significantly with an external rotation force (P = .037).Conclusion: Neither single nor double fixation for syndesmosis injuries provided multidirectionally stabilizing syndesmosis. Anatomic fixation directed from the posterior cortex of the fibula to the anterolateral edge of the tibia allowed dynamic stabilization of intact cadaver specimens. The metal screw provided very rigid fixation.Clinical Relevance: Optimal direction of the suture button can provide adequate stabilization of the ankle and could benefit athletes with syndesmosis injuries. [ABSTRACT FROM PUBLISHER]

Background: Although previous studies suggested that female patients are predisposed to increase graft laxity compared with male patients after single-bundle anterior cruciate ligament reconstruction using autogenous hamstring tendons, there have been no studies specifically examining gender-based differences in outcome after anatomic double-bundle anterior cruciate ligament reconstruction with hamstring tendon autografts.Hypotheses: (1) Female patients have significantly smaller hamstring graft diameters than do men for anatomic double-bundle anterior cruciate ligament reconstruction surgery; (2) female patients will have increased graft laxity compared with male patients after anatomic double-bundle anterior cruciate ligament reconstruction using autogenous hamstring tendons.Study Design: Cohort study; Level of evidence, 2.Methods: The consecutive 174 patients who underwent anatomic double-bundle anterior cruciate ligament reconstruction using autogenous hamstring tendons were enrolled. Of these patients, 49 women and 73 men were prospectively evaluated 2 years after surgery.Results: The diameters for anteromedial and posterolateral grafts in the female group were significantly smaller than those in the male group. On Lachman testing, 98% of the female group and 97% of the male group were rated as negative. Regarding the pivot-shift test, 80% of the female group and 85% of the male group were rated as negative. No significant differences were found between the female and male groups in these tests. The average side-to-side differences in the KT-2000 knee ligament arthrometer values were 1.3 mm in the female group and 1.4 mm in the male group; this difference between females and males was not statistically significant. The average Lysholm scores were 96.7 points in the female group and 97.2 points in the male group. Thirty-five cases (73%) in the female group and 54 cases (74%) in the male group were graded as normal on the International Knee Documentation Committee (IKDC) evaluation. There were no significant differences in Lysholm score or IKDC evaluation between the female and male groups.Conclusion: The results of assessment for ligament laxity at the 2-year postoperative evaluation in the female group were approximately identical to those of the male group after anatomic double-bundle anterior cruciate ligament reconstruction using autogenous hamstring tendons. Therefore, the present study suggests that anatomic double-bundle anterior cruciate ligament reconstruction using autogenous hamstring tendons provides satisfactory knee stability to female patients as well as male patients. [ABSTRACT FROM AUTHOR]

Background: Controversy persists as to whether double-bundle reconstruction of the anterior cruciate ligament (ACL) has any clinical advantage over single-bundle reconstruction. Several studies have used subjective and nonquantitative manual tests to evaluate the rotatory stability of the knee. The authors have developed a method to quantitate the rotatory stability of the ACL-deficient knee using open magnetic resonance imaging (MRI).Hypothesis: Anatomic double-bundle reconstruction restores rotatory stability significantly better than does single-bundle reconstruction.Study Design: Cohort study; Level of evidence, 3.Methods: Twenty-three consecutive patients treated with the single-bundle reconstruction (group S) and 25 consecutive patients treated with the anatomic double-bundle reconstruction (group D) were evaluated. Both reconstruction procedures were performed using hamstring tendon autografts. The Slocum anterolateral rotatory instability (ALRI) test was performed 1 year after surgery using open MRI. To assess rotatory stability, we measured the difference in anterior tibial translation between medial and lateral compartments in the sagittal plane and defined this difference as the ALRI value. In addition, clinical examinations consisting of the Lysholm knee score, Tegner activity score, KT-2000 arthrometer anterior translation examination, and the pivot-shift test were carried out.Results: The mean side-to-side difference in ALRI values was significantly less (P < .001) in double-bundle reconstruction (mean, 1.2 mm) than in single-bundle reconstruction (mean, 4.1 mm). The mean side-to-side difference in KT-2000 arthrometer measurements was significantly less (P = .014) in double-bundle reconstruction (mean, 1.2 mm) than in single-bundle reconstruction (mean, 2.6 mm). The difference in the incidence of positive pivot-shift tests between group S (43%) and group D (16%) did not reach the level of statistical significance (P = .058). No significant differences in Lysholm score or Tegner score between the groups were observed.Conclusion: The rotatory stability of anatomic double-bundle reconstruction was significantly better than the rotatory stability of single-bundle reconstruction. [ABSTRACT FROM AUTHOR]

Background: A double-network (DN) gel, which was composed of poly-(2-acrylamido-2-methylpropanesulfonic acid) and poly-(N,N′-dimetyl acrylamide) (PAMPS/PDMAAm), has the potential to induce chondrogenesis both in vitro and in vivo.Purpose: To establish the efficacy of a therapeutic strategy for an articular cartilage defect using a DN gel.Study Design: Controlled laboratory study.Methods: A 4.3-mm-diameter osteochondral defect was created in rabbit trochlea. A DN gel plug was implanted into the defect of the right knee so that a defect 2 mm in depth remained after surgery. An untreated defect of the left knee provided control data. The osteochondral defects created were examined by histological and immunohistochemical evaluations, surface assessment using confocal laser scanning microscopy, and real-time polymerase chain reaction (PCR) analysis at 4 and 12 weeks. Samples were quantitatively evaluated with 2 scoring systems reported by Wayne et al and O’Driscoll et al.Results: The DN gel–implanted defect was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type 2 collagen. Quantitative evaluation using the grading scales revealed a significantly higher score in the DN gel–implanted defects compared with the untreated control at each period (P < .0001). The mean relative values of type 2 collagen mRNAs in the regenerated tissue were obviously higher in the DN gel–implanted defect than in the untreated control at each period. The mean surface roughness of the untreated control was significantly higher than the normal cartilage at 12 weeks (P = .0106), while there was no statistical difference between the DN gel–implanted and normal knees.Conclusion: This study using the mature rabbit femoral trochlea osteochondral defect model demonstrated that DN gel implantation is an effective treatment to induce cartilage regeneration in vivo without any cultured cells or mammalian-derived scaffolds.Clinical Relevance: This study has prompted us to develop a potential innovative strategy to repair cartilage lesions in the field of joint surgery. [ABSTRACT FROM AUTHOR]

Background: The structural properties of a tendon autograft deteriorate during the remodeling phase after anterior cruciate ligament (ACL) reconstruction.Hypothesis: A local application of autologous synovium-derived cells cultured in medium supplemented with transforming growth factor β (TGFβ) may inhibit the deterioration of structural properties of the tendon graft after ACL reconstruction.Study Design: Controlled laboratory study.Methods: Fifty-two mature sheep were used. In each animal, the right knee underwent ACL reconstruction using the semitendinosus tendon autograft; then, the animals were divided into 5 groups of 10. No additional treatments were applied in group 1, whereas fibrin sealant was applied around the graft in group 2. In group 3, autologous synovium-derived cells cultured in standard medium were applied around the graft with fibrin sealant, whereas autologous synovium-derived cells cultured in TGFβ-supplemented medium were applied with fibrin sealant in group 4. In group 5, fibrin sealant containing 20 ng of TGFβ was applied around the graft. Each animal was sacrificed at 12 weeks after the surgery. In each group, 7 and 3 sheep were used for biomechanical and histologic evaluations, respectively. The remaining 2 sheep were used to confirm whether the applied cells infiltrated the graft at 1 week after surgery.Results: Confocal microscope observations showed that the applied cells that were labeled before implantation infiltrated into the superficial portion of the graft at 1 week. Biomechanically, the maximum load and the stiffness of groups 4 and 5 were significantly greater than those of groups 1, 2, and 3. Histologically, necrotic lesions were observed in the core portion of the midsubstance in groups 1 and 2. In groups 3, 4, and 5, no necrotic lesions were found in the midsubstance.Conclusion: A local application of autologous synovium-derived cells cultured in TGFβ-supplemented medium or a fibrin sealant containing TGFβ significantly inhibits the natural deterioration of the structural properties of the tendon graft after ACL reconstruction.Clinical Relevance: Administration of autologous synovium-derived cells cultured in TGFβ-supplemented medium or TGFβ and fibrin glue alone can be a potential cell-based therapy to prevent graft deterioration after transplantation or accelerate mechanical restoration of the deteriorated graft. [ABSTRACT FROM AUTHOR]

Background: After rotator cuff repair, the shoulder is immobilized in various abduction positions. However, there is no consensus on the proper abduction angle.Purpose: To assess the effect of shoulder abduction angle on the biomechanical properties of the repaired rotator cuff tendons among 3 types of double-row techniques.Study Design: Controlled laboratory study.Methods: Thirty-two fresh-frozen porcine shoulders were used. A simulated rotator cuff tear was repaired by 1 of 3 double-row techniques: conventional double-row repair, transosseous-equivalent repair, and a combination of conventional double-row and bridging sutures (compression double-row repair). Each specimen underwent cyclic testing followed by tensile testing to failure at a simulated shoulder abduction angle of 0° or 40° on a material testing machine. Gap formation and failure loads were measured.Results: Gap formation in conventional double-row repair at 0° (1.2 ± 0.5 mm) was significantly greater than that at 40° (0.5 ± 0.3 mm, P = .01). The yield and ultimate failure loads for conventional double-row repair at 40° were significantly larger than those at 0° (P < .01), whereas those for transosseous-equivalent repair (P < .01) and compression double-row repair (P < .0001) at 0° were significantly larger than those at 40°. The failure load for compression double-row repair was the greatest among the 3 double-row techniques at both 0° and 40° of abduction.Conclusion: Bridging sutures have a greater effect on the biomechanical properties of the repaired rotator cuff tendon at a low abduction angle, and the conventional double-row technique has a greater effect at a high abduction angle.Clinical Relevance: Proper abduction position after rotator cuff repair differs between conventional double-row repair and transosseous-equivalent repair. The authors recommend the use of the combined technique of conventional double-row and bridging sutures to obtain better biomechanical properties at both low and high abduction angles. [ABSTRACT FROM AUTHOR]

Background: Open curettage with bone graft has been the traditional surgical treatment for symptomatic unicameral calcaneal bone cyst. Endoscopic procedures have recently provided less invasive techniques with shorter postoperative morbidity. Hypothesis: The authors’ endoscopic procedure is effective for young athletes with symptomatic calcaneal bone cyst.Study Design: Case series; Level of evidence, 4.Methods: Of 16 young athletes with symptomatic calcaneal bone cyst, 13 underwent endoscopic curettage and percutaneous injection of bone substitute under the new method. Three patients were excluded because of short-term follow-up, less than 24 months. For the remaining 10 patients, with a mean preoperative 3-dimensional size of 23 × 31 × 35 mm as calculated by computed tomography, clinical evaluation was made with the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale just before surgery and at the most recent follow-up (mean, 36.2 months; range, 24-51 months), and radiologic assessment was performed at the most recent follow-up, to discover any recurrence or pathologic fracture. Furthermore, the 10 patients— all of whom returned to sports activities—were asked how long it took to return to initial sports activity level after surgery.Results: Mean ankle-hindfoot scale score improved from preoperative 78.7 ± 4.7 points (range, 74-87) to postoperative 98.0 ± 4.2 points (range, 90-100) (P < .001). Pain and functional scores significantly improved after surgery ( P < .01 and P < .05, respectively). Radiologic assessment at most recent follow-up revealed no recurrence or pathologic fracture, with retention of injected calcium phosphate cement in all cases. All patients could return to their initial levels of sports activities within 8 weeks after surgery (mean period, 7.1 weeks; range, 4-8 weeks), which was quite early as compared with past reports.Conclusion: Endoscopic curettage and injection of bone substitute appears to be an excellent option for young athletes with symptomatic calcaneal bone cyst for early return to sports activities, because it has the possibility to minimize the risk of postoperative pathologic fracture and local recurrence after early return to initial level of sports activities. [ABSTRACT FROM AUTHOR]

Background: The distribution pattern of subchondral bone density is considered to highly reflect the stress distribution across a joint under long-term physiologic loading conditions. Therefore, the biomechanical characteristics over the elbow joint surface under long-term loading conditions of baseball pitching can be determined by a measurement of the distribution pattern. Hypothesis: Stress distribution over the elbow joint surface alters with long-term pitching activities.Study Design: Cross-sectional study; Level of evidence, 3.Methods: Computed tomography (CT) imaging data from the dominant elbow of 10 nonthrowing athletes, 10 college baseball fielders, and 10 college baseball pitchers were collected for the current analysis. The distribution of subchondral bone density through the distal articular surface of the humerus was measured using a CT osteoabsorptiometry method. The quantitative analysis of the obtained data focused on location and size of the maximum density area at the articular surface.Results: The maximum density area of subchondral bone across the articular surface of the distal humerus was located in the posterior part of the trochlea in all subjects. This maximum density area was significantly increased in the pitcher group, compared with that in other groups. Additionally, the pitcher group demonstrated a significant distribution of the maximum density area in the anterior part of the capitellum.Conclusion: The results indicate that actual stress across the elbow is concentrated in the posterior part of the trochlea in humans. Baseball pitching may produce excessive or repetitive stress against not only this part, but also the anterior part of the capitellum. The majority of osteochondritis dissecans lesions affecting the elbow are found in the anterior part of the capitellum in throwing athletes. The results may support an important role of mechanical conditions in the cause of elbow osteochondritis dissecans. [ABSTRACT FROM AUTHOR]

Background: The authors previously identified a significant association between lumbar disc degeneration (LDDG) and cartilage intermediate layer protein (CILP) single nucleotide polymorphism (SNP) in collegiate male judokas.Hypothesis: A significant association between LDDG and the CILP SNP is observed in Japanese collegiate athletes.Study Design: Cross-sectional study; Level of evidence, 3.Methods: The participants were 601 trained collegiate athletes (male, 403; female, 198) from 7 different sports. Lumbar disc degeneration was evaluated using T2-weighted magnetic resonance imaging. Genotyping of the CILP gene (1184T/C) was performed by using DNA sequencing.Results: Among the 601 collegiate athletes, the odds ratio (OR) for the occurrence of LDDG with the CILP C allele was 1.4 (95% confidence interval [CI], 1.05-1.86). By using logistic regression analysis concomitant with the interaction term and the Wald test, the authors found that weight (OR, 1.04; 95% CI, 1.02-1.06), CILP genotype (CT: OR, 2.0; 95% CI, 1.24-3.15; CC: OR, 2.9; 95% CI, 1.09-7.74), and gender (OR, 2.1; 95% CI, 1.21-3.67) were significant risk factors for LDDG. These analyses also indicated that there was no effect of the CILP genotype on LDDG in female athletes.Conclusion: The CILP SNP 1184T/C is a risk factor for male collegiate athletes. Information regarding the CILP gene polymorphism may be important for preventing and managing lumbar disc diseases, especially in male athletes. [ABSTRACT FROM AUTHOR]

Background: Hypoxia and decreased blood supply have been proposed as risks for tendon rupture. Visualization of the vascularity of intact and torn rotator cuffs would be useful for improving treatments for rotator cuff tear.Purpose: To assess vascularity inside a tendon or an adjacent rotator cuff insertion point in patients differing in age and extent of damage to the tendon.Study Design: Cross-sectional study; Level of evidence, 3.Methods: Ten volunteers (all men) and 15 patients (10 men, 5 women) consented to participate in the study. Contrast agent for enhanced ultrasound was injected intravenously. Enhanced ultrasound images of the torn cuff and the contralateral shoulder were recorded for 1 minute. Four small regions of interest, the articular and bursal sides of the tendon and the medial and lateral sides of the bursa, were studied in all shoulders.Results: There was a significant decrease in blood flow in the intratendinous region in elderly subjects compared with young subjects, but age had no effect on blood flow in bursal tissue. Blood flow in ruptured rotator cuffs did not differ from that in intact rotator cuffs. The intraclass correlation coefficient for intraobserver reproducibility was 0.82 (95% confidence interval: 0.77-0.86).Conclusions: The findings of this investigation were the hypovascular pattern in intratendinous tissue compared with the subacromial bursa, the age-related decrease in intratendinous vascularity, and the hypovascular pattern in the tendon, regardless of rupture of the tendon. Clarification of vascular patterns inside or around the torn ends of a rotator cuff will assist in the development of successful treatments for torn rotator cuffs. [ABSTRACT FROM AUTHOR]