Medial Tibial Eminence Research Articles

Prospective Outcomes of Young and Middle-Aged Adults With Medial Compartment Osteoarthritis Treated With a Proximal Tibial Opening Wedge Osteotomy

The purpose of this study was to conduct a prospective outcome analysis of proximal tibial opening wedge osteotomies performed in young and middle-aged patients (aged <55 years) for the treatment of symptomatic medial compartment osteoarthritis of the knee. A consecutive series of young and middle-aged adults who underwent proximal tibial opening wedge osteotomies for symptomatic medial compartment osteoarthritis and genu varus alignment were prospectively followed up. Patients were evaluated with preoperative and postoperative modified Cincinnati Knee Scores and International Knee Documentation Committee objective knee subscores for knee effusions and the single-leg hop. Calculations were made of the preoperative and postoperative long-leg radiographic mechanical weight-bearing axis, patellar height (Insall-Salvati index), and tibial slope. A separate cohort of asymptomatic patients was used to quantify tibial plateau anatomy to provide an objective description of the lower extremity mechanical axis. There were 47 patients, with a mean age of 40.5 years, with a minimum of 2 years' follow-up, who formed this patient cohort. Modified Cincinnati Knee Scores improved significantly from 42.9 preoperatively to 65.1 at a mean of 3.6 years of follow-up. Radiographic analysis of a separate cohort showed the medial tibial eminence to be located at the 41% point along the tibial plateau from medial (0%) to lateral (100%). There was a significant improvement in malalignment: the mean mechanical axis passed through the tibial plateau at 23% of the distance along the proximal tibia preoperatively versus 54% postoperatively. The Insall-Salvati index decreased from 1.03 to 0.95 (P < .05), and posterior tibial slope increased from 9.4° to 11.7° (P < .05). Of the osteotomies, 3 (6%) were considered failures, defined by revision of the osteotomy or conversion to total knee arthroplasty. Performing proximal tibial opening wedge osteotomies to treat symptomatic medial compartment osteoarthritis in carefully selected patients leads to a significant improvement in subjective and objective clinical outcome scores with correction of malalignment at a mean of 3.6 years postoperatively. Level IV, therapeutic case series.

Bony and soft tissue landmarks of the ACL tibial insertion site: an anatomical study

To identify and describe reliable landmarks for tibial tunnel placement in anatomical ACL reconstruction. Eight non-paired cadaveric knees were used. After dissection, the tibial plateaus, menisci and ACL insertions were grossly observed to identify anatomical landmarks and relate them to the ACL insertion site. The specimens were scanned with a laser scanner, and 3-Dimensional images were obtained. Measurements of the ACL tibial insertion were taken. The center of the ACL and its bundles was measured regarding the distance from the medial tibial eminence and intermeniscal ligament. The medial tibial eminence demonstrated a constant relationship with the ACL tibial insertion site center and its bundles, as well as the intermeniscal ligament. The anterior root of the lateral meniscus had a variable relationship with the ACL tibial insertion. The length of the ACL tibial insertion was 18.1±2.8mm and the width was 10.7±1.9mm. The width of the AM bundle was 11.1±2.1mm and the PL 7.9±2.0mm. The ACL center was 9.1±1.5mm posterior to the intermeniscal ligament and 5.7±1.1mm anterior to a projected line from the apex of the medial tibial eminence. The center of the AM bundle was at 4.6±0.7mm posterior to the intermeniscal ligament. The center of the PL bundle was 1.4±0.7mm anterior to the medial tibial eminence. The medial tibial eminence and the intermeniscal ligament may be used as landmarks to guide the correct tunnel placement in an anatomical ACL reconstruction.

Anatomy of the anterior cruciate ligament

An internet-based literature review using the catalog of the National Library of Medicine for the keyword “anterior cruciate ligament” results in 5884 hits, thus reflecting the high importance of basic and clinical research. To achieve a satisfying surgical outcome after anterior cruciate ligament (ACL) reconstruction, a basic knowledge of the anatomy of the ACL is essential. The early manifestation of the ACL in the fetal knee joint suggests that the knee joint is early under the stabilization of the ACL. The origin of the ACL is at the medial surface of the lateral femoral condyle and runs distal-anterior-medial to the insertion at the medial tibial eminence. In the literature, a 2-bundle description of the ACL into anteromedial and posterolateral bundle has been accepted as a basis for the understanding the function of the ACL. Length and diameter of the native ACL may play an important role for choosing the type of graft and for the preparation of the graft. Microscopically, femoral origin and tibial insertion have the structure of a chondral apophyseal enthesis and can be separated into 4 layers. The collagen fibrils of the ACL are surrounded by connective tissue forming multiple fascicles. Proximal and distal vessels support a synovial plexus from which small vessels run into the ligament and align longitudinally parallel to the collagen bundles.

Reproducibility of anatomic tibial landmarks for anterior cruciate ligament reconstructions.

We evaluated the reproducibility of landmarks used for accurate anatomic placement of the tibial tunnel in anterior cruciate ligament reconstruction. Landmarks evaluated were the medial tibial eminence, the posterior cruciate ligament, the "over-the-back" position, the true posterior border of the tibia, and the posterior border of the lateral meniscus. Forty-two pairs of cadaveric knees were dissected, and anatomic measurements were made regarding the anterior cruciate ligament insertion and these various landmarks. Statistical analysis was used to confirm reproducibility and significance. Measurements based on the medial tibial eminence and posterior border of the meniscus were particularly erratic. The most reproducible anatomic landmark was the posterior cruciate ligament. The anterior border of the posterior cruciate ligament was consistently 6.7 mm posterior to the posterior border of the anterior cruciate ligament and 10.9 mm posterior to the central sagittal insertion point of the anterior cruciate ligament. The over-the-back position was consistently in contact with the anterior border of the posterior cruciate ligament if the knee was flexed with a posterior-directed force applied. In this position, the over-the-back position was equally reproducible as compared with the posterior cruciate ligament. Measurements gauged from the true posterior border of the tibia gave a second rigid bony landmark but with a wider standard deviation than the posterior cruciate ligament-based landmarks. The relative anterior-posterior dimension of the tibia did not correlate with the relationship between the anterior cruciate ligament and other anatomic landmarks.

MR imaging of displaced bucket-handle tear of the medial meniscus.

A bucket-handle tear of the meniscus is a vertical or oblique tear with longitudinal extension toward the anterior horn in which the inner fragment is frequently displaced toward the intercondylar notch with resultant mechanical locking of the knee joint. A precise MR diagnosis requires identification of the centrally displaced fragment because the peripheral nondisplaced component may have only a subtle truncated or foreshortened appearance that may escape detection. Eighteen consecutive cases of displaced bucket-handle tears of the medial meniscus diagnosed by MR had a characteristic low-signal band extending across the joint and projecting over the medial tibial eminence. The posterior portion was parallel and beneath the posterior cruciate ligament on both sagittal and coronal images. Arthroscopy confirmed the presence and location of the displaced fragment in all 18 cases. Awareness of this characteristic MR finding may increase the sensitivity of MR imaging in the diagnosis of bucket-handle tears of the medial meniscus.

Posttraumatic anterior cruciate ligament insufficiency as a cause of osteoarthritis in a knee joint.

The purpose of the present investigation was to examine and describe the osteoarthritic changes that chronic, partial or complete anterior cruciate ligament (ACL) insufficiency causes to the knee joint. The most characteristic findings in 77 patients with average follow-up of eight years were osteophytes and subchondral sclerosis of femoral and tibial medial condyles, tibial eminence and patella, as well as narrowing of medial or lateral joint space. Only five patients (14%) in the group with partial, but 28 (70%) of those with complete insufficiency of the ACL suffered from a clear posttraumatic osteoarthritis of the injured knee. In complete tears, the total extent of these pathological changes per patient was fourfold compared to the patients with partial tear. It was concluded that chronic, posttraumatic insufficiency of the ACL causes characteristic osteoarthritic changes to the injured knee and that the amount of these changes seems to depend on the amount of the insufficiency. Therefore, a quick restoration of the static and dynamic stability of the injured knee must be the privilege of every knee injury patient in order to prevent the development of premature osteoarthritis.

Osteoarthrosis in a knee joint due to chronic posttraumatic insufficiency of the medial collateral ligament. Nine-year follow-up.

The purpose of the present study was to examine and describe the osteoarthrotic changes that chronic, partial or complete medial collateral ligament (MCL) insufficiency causes to the knee joint. Forty-eight patients with partial and 25 with complete, isolated rupture of the MCL had a clinical and radiological reexamination of the knee on an average of nine years after the injury. In both groups the posttraumatic osteoarthrotic changes caused by the MCL insufficiency occurred very frequently on the medial side of the knee. The most characteristic findings were osteophytes and subchondral sclerosis of femoral and tibial medial condyles, tibial eminence and patella, ligament calcification of femoral medial condyle as well as narrowing of medial joint space. In patients with a partial tear 91% and in patients with complete tear 88% of all arthrotic changes caused by the insufficiency were one of these mentioned above, and other findings were only occasional. According to the radiological criteria of the authors none of the patients in the group with partial, but 17 (68%) of those with complete insufficiency of the MCL suffered from a clear posttraumatic osteoarthrosis of the injured knee. In complete tears the total extent of these pathological changes per patient was sixfold compared to the patients with a partial tear. It was concluded that chronic, posttraumatic insufficiency of the MCL causes characteristic medial side osteoarthrotic changes to the injured knee and that the amount of these changes seems to depend on the amount of the instability.(ABSTRACT TRUNCATED AT 250 WORDS)