Tatsuo Mae

Single- versus bi-socket anterior cruciate ligament reconstruction using autogenous multiple-stranded hamstring tendons with EndoButton femoral fixation *: A prospective study

PURPOSE This prospective study was conducted to compare the single-socket and the bi-socket anterior cruciate ligament (ACL) reconstruction techniques in terms of outcome. TYPE OF STUDY Nonrandomized control trial. METHODS There were 160 consecutive patients with unilateral chronic ACL insufficiency who underwent endoscopic single- or bi-socket ACL reconstruction alternately using multiple-stranded medial hamstring tendon and EndoButton (Smith & Nephew, Andover, MD) femoral fixation. All patients underwent the same postoperative rehabilitation protocol. Of them, 106 patients (57 single, 49 bi) were available for 2-year follow-up. RESULTS According to the IKDC Knee Ligament Evaluation Form, 23 patients (40%) of the single-socket group were subjectively graded as normal, 30 (53%) as nearly normal, and 4 (7%) as abnormal. Twenty-six patients (53%) of the bi-socket group were graded as normal, 21 (43%) as nearly normal, and 2 (4%) as abnormal (P =.19). The mean side-to-side anterior laxity difference (KT-1000 manual maximum force) was 0.9 +/- 1.8 mm for the single-socket group and 0.7 +/- 1.2 mm for the bi-socket group (P =.44). Fifty-three of 57 patients (93%) in the single-socket group and all patients in the bi-socket group showed anterior laxity differences of +/-3 mm or less (P =.12). There were no differences in thigh muscle strength between the groups. CONCLUSIONS Both single- and bi-socket ACL reconstruction using autogenous multiple-stranded hamstring tendons with EndoButton fixation provided satisfactory anterior stability, and there were no statistically significant differences in subjective results or measured restored stability between the 2 groups.

Human meniscus cell: characterization of the primary culture and use for tissue engineering.

Human meniscus cells from 47 surgically excised menisci were grown in primary culture. Cell proliferation and morphologic features were evaluated in three different culture media. Human meniscus cells showed three distinguishable cell types in monolayer culture: elongated fibroblastlike cells, polygonal cells, and small round chondrocytelike cells. These cells proliferated in Dulbecco’s modified Eagle’s medium, but by Day 7, elongated fibroblastlike cells became predominant. Cells did not proliferate in Ham’s nutrient mixture-F-12. In a mixture of Ham’s nutrient mixture-F-12 and Dulbecco’s modified Eagle’s medium, cells proliferated, maintaining their morphologic features and their ability to express messenger ribonucleic acids for aggrecan and Types I, II, and III collagen. Hyaluronan enhanced cellular proliferation without altering morphologic features or chondroitin sulfate production. Cultured human meniscus cells attached to a porous collagen sponge after cell seeding. Gene transfer was successful and an introduced gene was expressed by the cells, indicating that human meniscus cells can undergo gene manipulation. The finding that cells collected from small surgical specimens of human meniscus could be cultured, propagated, and seeded onto a collagen scaffold holds promise for the development of a cell-based, tissue engineered collagen meniscus.

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.

Allograft Anterior Cruciate Ligament Reconstruction

Tendon allograft is one of the useful ways to reconstruct the anterior cruciate ligament (ACL) without sacrificing normal tissues. Because it has advantages and disadvantages/concerns, this article makes suggestions regarding graft collection/selection, indication for the procedure, graft preparation, the currently performed technique to mimic the anatomic two bundles of ACL, and postoperative rehabilitation.

A Novel Technique of Arthroscopic Excision of a Symptomatic Os Trigonum

We describe a new arthroscopic excision technique for a symptomatic os trigonum. With the patient lying in a prone position, a posterolateral portal just lateral to the Achilles tendon, at the 5-mm level proximal to the tip of the fibula, is used for the arthroscope and an accessory posterolateral portal just posterior to the peroneal tendon at the same level is used for instruments. The synovial tissues are then debrided with a power shaver through the accessory posterolateral portal for better visualization. An elevator is used to release the fibrous tissue between the os trigonum and the talus. The os trigonum is completely excised with a grasper to visualize the flexor hallucis longus tendon. Radiographic control is helpful to check the position of the arthroscope if it happens to be inserted into the ankle joint as a result of the reduced subtalar joint space. Postoperatively, no immobilization is necessary, and full weight-bearing is allowed as tolerated. Three of us have performed 11 procedures with excellent results and no cases of complications. This arthroscopic excision technique for the symptomatic os trigonum is a safe and effective procedure.

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.

Recurrent Anterior Shoulder Dislocation Caused by a Midsubstance Complete Capsular Tear

BACKGROUND A midsubstance complete capsular tear is one of the well-known causes of anterior glenohumeral instability. However, its prevalence and clinical picture have not been well elucidated. The purpose of this study was to examine the prevalence of isolated complete capsular tears and to assess the clinical features as well as the results of surgical treatment of recurrent anterior glenohumeral instability caused by such tears. METHODS Three hundred and three shoulders underwent surgery to treat recurrent anterior glenohumeral instability at our institution during a five-year period. Twelve (4.0%) of these shoulders had an isolated complete capsular tear as the main pathological condition. Those twelve patients (nine male and three female) were the subjects of the present study. The average age at the time of the operation was twenty-five years. Patient age; the cause of the initial dislocation; the position of the arm at the initial dislocation; and the findings of the preoperative physical examination, of computed tomographic arthrography, and at surgery were assessed. Eleven patients underwent arthroscopic capsular repair, and one was treated with an open capsular repair. RESULTS The twelve patients either did not have a Hill-Sachs lesion or had a chondral indentation-type of Hill-Sachs lesion. When assessed with arthrography, the Hill-Sachs lesions were small compared with those in shoulders with an isolated Bankart lesion and, interestingly, they were quite similar in size to those seen with humeral avulsion of the inferior glenohumeral ligament. The average Rowe score for the twelve patients improved from 30.4 points preoperatively to 90.4 points at an average of thirty-one months postoperatively. CONCLUSIONS The prevalence of isolated complete capsular tears causing recurrent glenohumeral instability was 4.0% (twelve of 303). These tears were associated with either a small or no Hill-Sachs lesion. We believe that a complete capsular tear should be recognized as one of the essential lesions causing recurrent anterior shoulder dislocation. Arthroscopic examination and repair can provide effective treatment.

Hill-Sachs Lesions in Shoulders With Traumatic Anterior Instability Evaluation Using Computed Tomography With 3-Dimensional Reconstruction

Background: In patients with traumatic anterior shoulder instability, a large Hill-Sachs lesion is a risk factor for postoperative recurrence. However, there is no consensus regarding the occurrence and enlargement of Hill-Sachs lesions. Purpose: To investigate the influence of the number of dislocations and subluxations on the prevalence and size of Hill-Sachs lesions evaluated by computed tomography (CT) with 3-dimensional reconstruction. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: The prevalence and size of Hill-Sachs lesions were evaluated preoperatively by CT in 142 shoulders (30 with primary instability and 112 with recurrent instability) before arthroscopic Bankart repair. First, the prevalence of Hill-Sachs lesions was compared with the arthroscopic findings. Then, the size of Hill-Sachs lesions confirmed by arthroscopy was remeasured using the previous CT data. In addition, the relationship of Hill-Sachs lesions with the number of dislocations and subluxations was investigated. Results: Hill-Sachs lesions were detected in 90 shoulders by initial CT evaluation and were found in 118 shoulders at arthroscopy. The Hill-Sachs lesions missed by initial CT were 15 chondral lesions and 13 osseous lesions. However, all 103 osseous Hill-Sachs lesions were detected by reviewing the CT data. In patients with primary subluxation, the prevalence of Hill-Sachs lesions was 26.7%, and the mean length, width, and depth of the lesions (calculated as a percentage of the diameter of the humeral head) were 9.0%, 5.3%, and 2.1%, respectively, while the corresponding numbers for primary dislocation were 73.3%, 27.7%, 14.8%, and 7.0%, all showing statistically significant differences. Among all 142 shoulders, the corresponding numbers were, respectively, 56.3%, 20.7%, 11.2%, and 4.8% in patients who had subluxations but never a dislocation; 83.3%, 33.4%, 19.1%, and 7.6% in patients with 1 episode of dislocation; and 87.5%, 46.8%, 22.2%, and 10.2% in patients with ≥2 episodes, all showing statistically significant differences. There were no differences in lesion measurements in relation to the number of subluxations. Conclusion: Computed tomography is a useful imaging modality for evaluating Hill-Sachs lesions except for purely cartilaginous lesions. Hill-Sachs lesions were more frequent and larger when the primary episode was dislocation than when it was subluxation. Among patients with recurrent episodes of complete dislocation, the prevalence of Hill-Sachs lesions is increased, and the lesions are larger.