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At least 433 records · Page 24Linked to original sources
PubMed1980

Knee surgery: a philosophy.

Functional disability should be proven before surgery is performed. If the knee demonstrates disability and simultaneously demonstrates muscle atonia and atrophy or contracture and imbalance, this dynamic support of the knee should be corrected preoperatively as far as possible and then the disability reevaluated before proceeding with surgery. A complete, documented knee examination must precede ancillary diagnostic procedures. Too often I see patients still in trouble with knees previously operated upon, who relate they had a cursory knee examination or no knee examination and were told that now there are modern diagnostic procedures such as arthrography and arthroscopy so they can be admitted to the hospital for these procedures with a resultant accurate diagnosis. This concept is not true! No ancillary procedure supercedes a knowledgeable history and clinical examination. The surgeon should operate only on the basis of objective demonstration of the need for operation, not on the basis of the history alone. In my estimation, rehabilitation accounts for 50 percent of a successful result following injury or operation. Remember, anatomy is the key to the knee.

Cartilage, Articular↗
PubMed2001

Anatomy, histologic features, and vascularity of the adult acetabular labrum.

Acetabular labrum tears have been implicated as a cause of hip pain in adult patients. Few studies describe the anatomy, histologic features, and microvasculature of the acetabular labrum and labral tears. Fifty-five embalmed and 12 fresh-frozen adult hips with a mean age of 78 years (range, 61-98 years) were studied. Of these, 96 % (53 of 55) of the hips had labral tears, with 74% of the tears located in the anterosuperior quadrant. Histologically, the fibrocartilaginous labrum was contiguous with the acetabular articular cartilage through a 1- to 2-mm zone of transition. A consistent projection of bone extends from the bony acetabulum into the substance of the labrum that is attached via a zone of calcified cartilage with a well-defined tidemark. Two distinct types of tears of the labrum were identified histologically. The first consisted of a detachment of the fibrocartilaginous labrum from the articular hyaline cartilage at the transition zone. The second consisted of one or more cleavage planes of variable depth within the substance of the labrum. Both types of labral tears were associated with increased microvessel formation seen within the tear. The acetabular labrum tear appears to be an acquired condition that is highly prevalent in aging adult hips. Labral tears occur early in the arthritic process of the hip and may be one of the causes of degenerative hip disease.

Acetabulum↗
PubMedDate not supplied

MR fat suppression technique in the evaluation of normal structures of the knee.

The chopper fat suppression (CFS) pulse sequence, which is a phase sensitive implementation of the Dixon fat suppression method and the spin echo (SE) pulse sequence, was used in the evaluation of anatomic structures of the normal knee using 48 sets of imaging sequences in six volunteers using a repetition time/echo time combination of 1,500/30, 60 ms. A demonstration of the CFS technique in 10 patients with suspected knee pathology is also presented. A semiquantitative grading scale was established to rate anatomic visualization and used to compare CFS and SE pulse sequence techniques. The results in normal subjects demonstrate that hyaline cartilage is significantly better visualized by fat suppression pulse sequence than by conventional SE pulse sequence in the coronal and sagittal planes of imaging (p less than 0.001). The preliminary results from patients studies suggest that CFS imaging may be useful in the evaluation of meniscal tears, in the differentiation of hyaline cartilage from joint fluid, and in the detection of both soft tissue and bone injuries.

Adipose Tissue↗
PubMed1996

Proprioceptive mechanisms in the cruciate ligaments: an electromyographic study on reflex activity in the thigh muscles.

The hypothesis of a proprioceptive mechanism arising from mechanoreceptors in the cruciate ligaments and with efferences to the thigh muscles is investigated in an animal model. Electromyographic (EMG) studies of the quadriceps and hamstrings muscles were performed in six sheep anesthetized by intravenous injection of chloralose on applying static and dynamic shear forces to isolated fascicle bundles in the anterior (ACL) and posterior (PCL) cruciate ligaments at 200 to 500 N and 50 to 200 N/sec, respectively. With the help of an external fixator, the knee joint position was varied at 25 to 150 degrees. The relative preload of the anteromedial and posterolateral fascicles in the ACL and the anterior and posterior fascicles in the PCL induced by variation of the joint angle was measured with the help of strain gages. By static and dynamic loading of the anteromedial group of the ACL, EMG activity in the hamstrings increases significantly to 159 +/- 22 and 257 +/- 46 microV seconds, respectively (p < 0.001), with a simultaneous suppression of the quadriceps activity. Static and dynamic loading of the posterolateral ACL group results in a significant excitation of the quadriceps with mean potentials of 142 +/- 29 and 173 +/- 23 microV seconds, respectively (p < 0.001). Mechanical shear applied both to the anterior and posterior fascicles of the PCL induces a significant activation of the ipsilateral quadriceps muscles with a simultaneous inhibition of the hamstrings (p < 0.001). The quality of mechanical loading, i.e., static or dynamic shear, determines the degree of muscular recruitment significantly (p < 0.01). The joint angle contributes to a modulation in the quantitative EMG excitation. Linear regression analysis of the integrated EMG potential values and the amount of passive preload induced by the respective joint position results in a close correlation (r = + 0.78 to + 0.86). The results lead to the conclusion that a proprioceptive mechanism exists that arises from the cruciate ligaments and influences the tone in the thigh muscles. The degree of muscle excitation on mechanical ligament loading is modulated by the amount of preload in the ACL and PCL and the quality of load applied.

Animals↗
PubMed2006

Evaluation and treatment of medial collateral ligament and medial-sided injuries of the knee.

Injuries to the medial side of the knee are not always isolated injuries of the superficial medial collateral ligament. Medial-sided injuries can also involve the deep medial collateral ligament, the posteromedial corner, or the medial meniscus. Magnetic resonance imaging is a useful adjunct to the physical examination; however, the extent of medial-sided injuries is frequently underappreciated on these images. An understanding of the anatomy and biomechanics of the medial side of the knee and a thorough physical examination aids the physician in determining the full extent of injury and helping the physician to treat each unique injury pattern.

Biomechanical Phenomena↗
PubMed1998

A microstructural model for the tensile constitutive and failure behavior of soft skeletal connective tissues.

We propose a microstructural model for the uniaxial tensile constitutive and failure behavior of soft skeletal connective tissues. The model characterizes the tissues as two-phase composites consisting of collagen fibers embedded in ground substance. Nonlinear toe region behavior in the stress versus strain curve results from the straightening of crimped fibers and from fiber reorientation. Subsequent linear behavior results from fiber stretching affected by fiber volume fraction, collagen type, crosslink density, and fiber orientation. Finally, the tissue fails when fibers successively rupture at their ultimate tensile strain. We apply the model to tendon, meniscus, and articular cartilage. The model provides a consistent approach to modeling the tensile behavior of a wide range of soft skeletal connective tissues.

Animals↗
PubMedDate not supplied

Anatomic reconstruction of the posterior cruciate ligament after multiligament knee injuries. A combination of the tibial-inlay and two-femoral-tunnel techniques.

BACKGROUND: Neither operative nor nonoperative treatment of posterior cruciate ligament rupture after multiligament knee injuries have shown very favorable outcomes. HYPOTHESIS: Reconstruction of the posterior cruciate ligament by combining the tibial-inlay and two-femoral-tunnel techniques will result in improved stability and functional outcomes. STUDY DESIGN: Prospective cohort study. METHODS: Twenty-nine patients with 30 posterior cruciate ligament ruptures and multiligament knee injuries treated with the combined technique were evaluated with clinical, radiographic, and functional outcome measures. RESULTS: All patients had a clinical examination result indicating joint stability (0 or 1+) at an average follow-up of 25 months (range, 15 to 39). Twenty-three knees had no laxity, and seven had 1+ laxity. The KT-2000 arthrometer data documented less than 0.5 mm of side-to-side mean difference for both posterior displacement and total anterior-posterior displacement at both 30 degrees and 70 degrees of knee flexion. Knee range of motion was a mean extension of 1 degrees (range, 0 degrees to 10 degrees ) and a mean flexion of 124 degrees (range, 75 degrees to 145 degrees ). Mean Lysholm knee score was 89.4. CONCLUSIONS: Reconstruction with a combination tibial-inlay and two-femoral-tunnel technique provides good results after multiligament knee injuries. All patients had a stable posterior cruciate ligament at most recent clinical follow-up, and 77% had no laxity at all.

Adolescent↗
PubMed1992

Magnetic resonance imaging of reconstructed knee ligaments.

Reconstruction of knee ligaments is now a common orthopedic procedure. Patients are frequently referred for magnetic resonance imaging (MRI) after later reinjury, and the ability to recognize normal reconstructed knee ligaments is therefore becoming increasingly important. This pictorial essay demonstrates various reconstructions of the cruciate and the collateral ligaments, as well as several abnormalities of these ligaments.

Anterior Cruciate Ligament↗
PubMed1991

[Proton spin and computerized tomography in ligament injuries of the knee joint].

UNLABELLED: In a prospective study we evaluated the use of cat-scan an MRI in 106 patients with chronic complaints and acute injuries of the knee joint. All patients went to surgery afterwards. A total of 30 patients suffered from acute or chronic ligament ruptures. There were 20 ACL ruptures, 2 PCL ruptures, 3 MCL ruptures, and 2 LCL ruptures. In patients with ACL ruptures the MRI had a sensitivity of 80%, a specificity value of 80%, and a negative predictive value of 95%; whereas cat-scan had a sensitivity of 90%, a specificity of 95%, an accuracy of 94%, a positive predictive value of 82%, and a negative predictive value of 98%. All complete ACL ruptures we correctly diagnosed. However, 4 partial ACL ruptures were missed by MRI and 2 partial ruptures were missed by cat-scan. All other ligament ruptures (PCL, MCL, LCL) except one MCL rupture were correctly diagnosed by MRI as well as by cat-scan. CLINICAL RELEVANCE: In this study cat-scan and MRI proved to have a very high negative predictive value. Having a negative result in one of these imaging techniques means that a rupture of a ligament is highly unlikely. This may have influence on the number of unnecessary invasive arthroscopic procedures.

Anterior Cruciate Ligament Injuries↗
PubMedDate not supplied

[Therapeutic possibilities of shoulder arthroscopy at the orthopedic clinic of the Charité and the surgical clinic Berlin-Weissensee].

We report on arthroscopic procedures of 279 shoulder joints which were done in two hospitals of East-Berlin. We stress out the intention to arthroscopic diagnostic and simultaneous surgery. Arthroscopic surgery was mainly performed as resections and exstirpations. In cases of luxation and severe rotator cuff tears the open revision was necessary to perform.

Arthroscopes↗
PubMed1985

[Experimental study of hypertrophy of the femoral head--with special reference to the effects of the surgical procedure on the hip joint].

This experimental study was performed to clarify how a surgical procedure to the hip joint causes hypertrophy of the femoral head. Young rabbits were used for this experiment. The following results were obtained. In the rabbits with sectioned ligamentum teres, some cases showed complete dislocation on X-ray. The incidence of the hypertrophy of the femoral head was very low in this group. Except in these rabbits with dislocation, the hypertrophy of the femoral head appeared in any group subjected to surgical procedure, and at especially high rates in those subjected to the section of ligamentum teres and/or edge resection of acetabular cartilage. In the cases in which the edge of the acetabular cartilage was resected, and in other cases of surgical procedure as well, acetabular dysplasia often resulted. In these cases the hypertrophy of the femoral head was observed more frequently than in others. In summary, surgical procedure to the hip joint and postoperative abnormal stress to the femoral head contribute to the development of the hypertrophy of the femoral head especially in the cases in which acetabular factors are not negligible.

Acetabulum↗