Konsei Shino

Direct anterior cruciate ligament insertion to the femur assessed by histology and 3-dimensional volume-rendered computed tomography.

PURPOSE The purpose of this study was to histologically identify the direct and indirect insertion of the femoral anterior cruciate ligament (ACL) insertion. Furthermore, we quantitatively measured the direct femoral insertion area by use of the 3-dimensional (3D) volume-rendered (VR) computed tomography (CT) model. METHODS By use of 8 intact cadaveric knees, the lateral femoral condyle including the ACL attachment was sectioned for histologic examination in 3 oblique-axial planes parallel to the roof of the intercondylar notch and in the sagittal planes. Before sectioning, these knees had been subjected to CT to obtain 3D VR images of the femur. Once the direct insertion of the ACL was identified on each histologic section, the corresponding image was superimposed on the corresponding CT image. RESULTS The direct ACL insertion, in which dense collagen fibers were connected to the bone by the fibrocartilaginous layer, was microscopically identified at the region between the posteromedial articular cartilage margin of the lateral femoral condyle and the linear bony ridge 7 to 10 mm anterior to the articular cartilage margin. Meticulous comparison of histologic analysis and the 3D VR CT model showed that the ACL direct insertion coincided with a crescent-shaped hollow just behind the linear bony ridge. The direct insertion measured 17.4 +/- 0.9 mm (mean +/- SD) in length, 8.0 +/- 0.5 mm in width, and 128.3 +/- 10.5 mm(2) in area. CONCLUSIONS The direct insertion of the ACL is located in the depression between the residents ridge and the articular cartilage margin on the lateral femoral condyle. It measured 17.4 +/- 0.9 mm in length, 8.0 +/- 0.5 mm in width, and 128.3 +/- 10.5 mm(2) in area. CLINICAL RELEVANCE Delineation of the ACL femoral direct insertion by 3D VR CT could be a useful tool for planning of accurate femoral tunnel positioning in anatomic ACL reconstruction.

Rectangular Tunnel Double-Bundle Anterior Cruciate Ligament Reconstruction with Bone-Patellar Tendon-Bone Graft to Mimic Natural Fiber Arrangement

We describe our current technique of anatomic, double-bundle (DB), rectangular tunnel anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BPTB) graft. This technique mimics the natural, or anatomic, arrangement of the native ACL fibers. This technique has the following advantages: (1) creation of a DB ACL reconstruction with a single BPTB graft; (2) maximization of graft-tunnel contact area; (3) containment of the tunnel apertures within the anatomic ACL attachment footprint; (4) rotational control of the graft within the tunnels during and after fixation; and (5) preservation of notch anatomy.

Arthroscopic stapling for detached superior glenoid labrum

Superior labral tears of the shoulder involve the biceps tendon and labrum complex which may be detached, displaced inferiorly, and interposed between the glenoid and the humeral head. We have treated ten young athletes with painful shoulders due to this lesion by arthroscopic stapling. Arthroscopy at the time of staple removal, after three to six months, showed that all the lesions had been stabilised. Clinical review at over 24 months showed an excellent or good result in 80%. The two relative failures were due in one to residual subacromial bursitis, and the other to multidirectional shoulder instability. Arthroscopic stapling can restore the shoulder anatomy, and it is recommended for active adolescent athletes with this lesion.

The influence of skeletal maturity on allogenic synovial mesenchymal stem cell-based repair of cartilage in a large animal model.

One of the potential factors that may affect the results of mesenchymal stem cell (MSC)-based therapy is the age of donors and recipients. However, there have been no controlled studies to investigate the influence of skeletal maturity on the MSC-based repair of cartilage. The purpose of this study was to compare the repair quality of damaged articular cartilage treated by a scaffold-free three-dimensional tissue-engineered construct (TEC) derived from synovial MSCs between immature and mature pigs. Synovial MSCs were isolated from immature and mature pigs and the proliferation and chondrogenic differentiation capacities were compared. The TEC derived from the synovial MSCs were then implanted into equivalent chondral defects in the medial femoral condyle of both immature and mature pigs, respectively. The implanted defects were morphologically and biomechanically evaluated at 6 months postoperatively. There was no skeletal maturity-dependent difference in proliferation or chondrogenic differentiation capacity of the porcine synovial MSCs. The TEC derived from synovial MSCs promoted the repair of chondral lesion in both immature and mature pigs without the evidence of immune reaction. The repaired tissue by the TEC also exhibited similar viscoelastic properties to normal cartilage regardless of the skeletal maturity. The results of the present study not only suggest the feasibility of allogenic MSC-based cartilage repair over generations but also may validate the use of immature porcine model as clinically relevant to test the feasibility of synovial MSC-based therapies in chondral lesions.

Second-look arthroscopy after meniscal repair. Review of 132 menisci repaired by an arthroscopic inside-out technique

From 1986 to 1993, we repaired 278 torn menisci in 264 patients using an arthroscopically assisted inside-out technique. A total of 132 meniscal repairs in 122 patients were evaluated by second-look arthroscopy. At review, only nine patients had meniscal symptoms, such as locking, swelling or pain. Ninety-seven menisci (73%) had healed completely at the repair site, but there were new tears in different areas of 21 menisci, some of which had complete healing at the repair site. Incomplete healing, seen in 23 menisci (17%), was frequently near the popliteus tendon, most commonly where there had been an associated anterior-cruciate-ligament injury. Arthroscopically-assisted meniscal repair seems to be a reliable procedure, but some clinically successful cases had incomplete healing at the repair site or a newly-formed tear in the meniscal body or both. These lesions may cause meniscal symptoms to appear at a later date.

Arthroscopic Anterior Cruciate Ligament Reconstruction Using Fresh-Frozen Bone Plug-Free Allogeneic Tendons : 10-Year Follow-up

PURPOSE To evaluate the long-term outcomes following arthroscopic-assisted anterior cruciate ligament (ACL) reconstruction using fresh-frozen allogeneic tendon. METHODS Sixty-one athletically active patients (mean age at surgery, 20.9 years) who had arthroscopic-assisted ACL reconstruction using fresh-frozen free tendon allograft underwent physical examination, instrumented laxity measurement, radiographs, and thigh muscle strength at 10 to 14 years (mean, 11.5) postoperatively, and these data were compared with results of similar measurements obtained at 2 years postoperatively. RESULTS Lachman test and pivot shift test were maintained as negative in 53 (87%) and 52 (85%) patients at follow-up, respectively. Quantitative measurements using the KT-2000 knee arthrometer showed 1.6 +/- 1.3 (mean +/- SD) mm in the side-to-side difference, and no more than 3 mm in 56 patients (92%) at final follow-up. All but one was assessed as normal or nearly normal by International Knee Documentation Committee score. Patient activity level was decreased at the long-term follow-up, but this change was mainly associated with changes in social context (e.g., graduation from school) rather than with knee limitations. None of the patients experienced deep infection or graft rejection. Degenerative joint disease on radiographs was seen in 13 out of 15 patients (87%) whose menisci had been excised, whereas it was observed in 12 out of 46 (26%) whose menisci had been preserved. CONCLUSIONS A series of 61 patients with fresh-frozen bone plug-free tendon allografts using a 2-incision technique for arthroscopic ACL reconstruction results in long-term knee stabilization and functioning among young active individuals while simultaneously avoiding graft harvest site morbidity. LEVEL OF EVIDENCE Level IV, therapeutic case series.

Optimization of Graft Fixation at the Time of Anterior Cruciate Ligament Reconstruction: Part II: Effect of Knee Flexion Angle

Background There is no consensus about flexion angle of the knee at the time of graft fixation in anterior cruciate ligament reconstruction. Purpose To evaluate the effect of flexion angle at the final graft fixation on the positional relationship as well as the load between femur and tibia. Study Design Controlled laboratory study. Methods Six intact cadaveric knees were passively flexed and extended under 6 degrees of freedom with the robotic system developed in our laboratory, while their 3-dimensional paths were recorded. Anterior cruciate ligament reconstruction was performed with a single-socket technique using autogenous quadrupled hamstring tendons, while the graft was fixed at 0° (group A) 20° (group B) or 90° (group C) with a constant initial tension of 44 N. The knees then repeated the same movement as before while the relative position between femur and tibia was recorded. The load in the femorotibial joint was also calculated based on the principle of superposition. Results Posterior displacement of the tibia compared with the normal knee was the smallest in group B at all flexion angles, while the load between tibia and femur in group B was also the smallest and the closest to the normal knee. Conclusion As the positional relationship as well as the load between femur and tibia in group B was the closest to that in the normal knee, 20° of flexion is the most desirable of the positions tested for graft tensioning and fixation at the time of anterior cruciate ligament reconstruction. Clinical Relevance The tibia-femur position is well retained when the graft was fixed at 20° of flexion in anterior cruciate ligament reconstruction.

Dual tunnel medial patellofemoral ligament reconstruction for patients with patellar dislocation using a semitendinosus tendon autograft.

The purpose of this study was to describe a safer and more anatomical technique of MPFL reconstruction and to report the short-term results. The subjects included 20 patients with patellar dislocation with a mean age of 23. The operation was performed using a double-looped autogenous semitendinosus tendon graft. Two small bone tunnels were made at the medial edge of the patella, mimicking the wide patellar insertion of the MPFL and a bone tunnel was made at the femoral insertion site. The free ends of the graft attached to the patella and the loop end was fixed to the femoral side. Five patients were available for follow-up interviews by telephone and the remaining 15 were directly examined by physical examination and radiographic evaluation at 2 years or longer postoperatively. The average follow-up period was 30 months. Re-dislocation or patellar fracture was not seen in any patients. The average Kujalas score was 96 with a range from 84 to 100. Six patients were classified as excellent and 14 as good, according to the Crosby and Insall grading system. Radiographically, narrowing of the patellofemoral joint space was observed in 2 cases with previous osteochondral fracture out of those who were directly examined. The dual tunnel MPFL reconstruction produces favorable results in subjective and functional assessment of outcome without complications.

Optimization of Graft Fixation at the Time of Anterior Cruciate Ligament Reconstruction Part I: Effect of Initial Tension

Background Although anterior cruciate ligament (ACL) reconstructions are frequently performed, little is known about the effect of initial tension on an ACL graft at the time of its fixation. Purpose The objective of this study was to evaluate the effects of initial tension on the relative position and the load between femur and tibia during passive motion. Study Design Controlled laboratory study. Methods Seven cadaveric knees underwent a passive flexion-extension movement from 0° to 90° with a robotic system developed in the authors’ laboratory under 6 degrees of freedom, while their 3-dimensional paths were recorded. A single-socket ACL reconstruction was performed with an autogenous quadrupled hamstring tendon graft, while the knees underwent the same movement as before with the initial graft tension of 22 N (group A), 44 N (group B), or 88 N (group C) at 20°. The relative position between the femur and the tibia was recorded, and the load in the femorotibial joint was calculated using the principle of superposition. Results The tibia in group C was most posteriorly positioned among the 3 groups (an average posterior translation of 0.6, 1.3, and 2.6 mm in groups A, B, and C, respectively). The tibia also moved proximally and laterally with external and valgus rotation with an increase in initial tension, and consequently the load in the femorotibial joint increased at ail flexion angles. Conclusion With an increase in initial tension, the tibia moved posterolaterally with external and valgus rotation, and consequently the contact force in the femorotibial joint increased. Clinical Relevance Excessive initial tension at the time of ACL reconstruction may potentially bring deleterious effects to the articular surface, leading to cartilage degeneration.

The arrangement and the attachment areas of three ACL bundles

PurposeNormal anterior cruciate ligament (ACL) can be divided into three fiber bundles—i.e., anteromedial (AM), intermediate (IM), and posterolateral (PL) bundles. However, their arrangement and attachment areas had remained unclear. The purpose of this study was to clarify the arrangement of these three ACL fiber bundles and their attachment sites, and to provide information on the tunnel placement in anatomical triple bundle ACL reconstruction.MethodsSeven non-embalmed human frozen knees were used. ACL fibers were bluntly divided into three bundles. A different-colored thread was wound around each fiber bundle in a spiral. Macroscopical investigation was performed to clarify the arrangement of three ACL bundles. Each fiber bundle was carefully detached from the femur and tibia, and then the distribution of attachment sites of each fiber bundle was observed.ResultsIn knee extension, all bundles consisting of AM, IM and PL bundles ran parallel to each other in the lateral view from the medial side. The AM bundle overlapped with the IM bundle, whereas the PL bundle ran parallel to them on the distal aspects. As the knee flexion increased, the bundles became twisted around each other. On the tibial side, the attachment areas of three fiber bundles formed a triangular shape showing arrangements of AM, IM and PL bundles on the anteromedial, anterolateral and posterior aspects, respectively. On the femoral side, the PL bundle was attached on the distal-posterior areas; the IM bundle was attached distal-anterior to the AM bundle. They were arranged in a triangular shape on the tibia side as well.ConclusionThis study clarified the arrangement of three fiber bundles of ACL and detailed geographical locations of their attachment sites. The detailed anatomic description of the natural ACL attachment might suggest to surgeons where to make tunnels during anatomical double/triple bundle ACL reconstruction.