Arthroscopy: The Journal of Arthroscopic and Related Surgery 4(4):297-300 Published by Raven Press, Ltd. © 1988 Arthroscopy Association of North America

Abstracts From the Literature

Editor's Comments: With this issue, Arthroscopy initiates a new feature: abstracts taken from cur- rent literature that should be o f interest to arthro- scopic surgeons. (Although many of the articles are not arthroscopic in their scope, they should benefit anyone who is primarily an orthopedic surgeon, al- beit with a somewhat narrow interest in arthros- copy.)

S. Ward Casscells, M.D., Editor

Quadriceps Insufficiency following Repair of the An- terior Cruciate Ligament. By Charles LoPresti, Don- ald T. Kirkendall, Glenn M. Street, and Alden W. Dudley Jr. J Orthrop Sports Phys Ther 1988;9: 245-9.

Patients typically return to activity approxi- mately 12 months after repair of the ACL ligament. This study was undertaken to quantify quadriceps size and function at 1 year postsurgery. Bilateral isokinetic torque measurements , tomographic scans, muscle biopsies, and anthropometrics were performed on 13 patients (3 women, 10 men) 13 months after surgery. The operative leg was 3% smaller in circumference, 10% smaller in total mus- cle area, 12% smaller in quadriceps area (all p < 0.05), and had a 9% larger subcutaneous fat area (p = 0.06). No difference in hamstrings area was seen. Isokinetic torques for the quadriceps were reduced by 11-15% in the operative leg (p < 0.05), with no difference seen between the hamstrings torques. Types I and II fibers were clinically smaller in both legs. Type II fibers were significantly (p < 0.05) reduced in the operative leg. It was concluded that (1) leg circumference was a poor indicator of muscle size due to the selective fat deposition in the oper- ative leg, (2) the cross-sectional area of muscle was proportional to isokinetic torque at 240/s, and (3) there were clinically and statistically significant iso- kinetic torque differences between quadriceps 13 months after surgery.

Shoulder Arthroscopy: Current Indications and Tech- niques. By Harvard Ellman. Orthopaedics 1988; 11:45-51.

Arthroscopic subacromial decompression is an alternative to open anterior acromioplasty in the

treatment of chronic stage II impingement syn- dromes before the development of full-thickness ro- tator cuff tear. Patients with massive and otherwise unrepairable cuff tears have achieved significant pain relief from arthroscopic decompression and debridement of the floppy and irregular cuff mar- gins. Routine repairable full-thickness cuff tears are best treated by open reconstruction. The arthro- scope is an adjunct in confirming the diagnosis and direction of shoulder instability. Arthroscopic sta- bilization is most feasible when the anterior gleno- humeral ligament/labral complex is detached. The introduction of a metal staple is controversial; how- ever, reported complications are diminishing with experience. Alternate methods of stabilization are being investigated. Effective arthroscopic tech- niques have been established for the removal of loose bodies, and the treatment of calcific tendoni- tis, septic arthritis, and other disorders.

A Review of Applications of MRI in Soft Tissue and Bone Tumors. By John A. Kalmar, John J. Eick, Christopher R. B. Merritt, Stanton E. Shuler, Ken- neth D. Miller, Gordon B. McFadand, and Jerry J. Jones. Orthopedics 1988;11:417-25.

Due to excellent soft tissue contrast and multipla- nar imaging capability, magnetic resonance imaging (MRI) is assuming a major role in recognition, stag- ing, and treatment planning of soft tissue and bone tumors. Direct sagittal, coronal, and axial images permit assessment of in t raosseous and extra- osseous extension of tumors and their relationship to the joints and neurovascular structures and de- tection of "skip" lesions. MRI allows improved de- tection of recurrent tumors in the presence of non- ferromagnetic metallic implants as compared to computed tomography (CT). In the evaluation of soft tissue tumors, MRI is more sensitive than CT and allows differentiation among fat, muscle, ten- don, bone, and vascular structures based on signal characteristics. Over a period of 18 months, 100 soft tissue masses and bone tumors were evaluated us- ing MRI. Spin echo sequences with T~- and T 2- weighted images were most valuable in differentiat- ing normal and abnormal tissues. Calculated com- parative measurements of relaxation times showed

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no reliable difference between benign and malignant tumors.

Operative Versus Non-Operative Treatment of Recent Injuries to the Ligaments of the Knee. A Prospective Randomized Study. By Rolf Sandberg, Bengt Balk- fors, Bo Nilsson, and Nils Westlin. J Bone Joint Surg [Am] 1987;69:1120-6.

Two hundred consecutively seen patients with in- jury to either the anterior cruciate ligament or the medial collateral ligament, or both, were randomly treated by either a conservative or a surgical regi- men. Injuries to the medial collateral ligament could not be demonstrated to benefit from surgical treat- ment in any respect--with or without surgery the results were excellent. Injuries to the anterior cru- ciate ligament recovered more rapidly without sur- gery but otherwise the results differed between the groups in only one respect: the pivot-shift test was more often positive after conservative treatment. The results were good in both treatment groups even though most of the patients with an injury of the anterior cruciate ligament were somewhat less pleased with the outcome after a period of time re- gardless of the method of treatment.

The Accuracy of Selective Magnetic Resonance Imag- ing Compared with the Findings of Arthroscopy of the Knee. By Capt. David W. Polly, Jr., Maj. John J. Callaghan, Lt. Col. Randall A. Sikes, Lt. Col. James W. McCabe, Capt. Kevin McMahon, and Col. Carlton G. Savory. J Bone Joint Surgery [Am] 1988;70:192-8.

The results of selective magnetic resonance im- aging of the knee were compared with those of ar- throscopy in a prospective series of 50 patients. A specifically designed protocol for imaging, produc- ing T1 sagittal images interleaved at 4 mm while the patient's foot was in 20 ° of external rotation, was used. This technique, called selective magnetic res- onance imaging, yielded excellent visualization of the posterior cruciate ligament, medial meniscus, and lateral meniscus in all patients. However, the anterior cruciate ligament (ACL) was well visual- ized in only 76% of the patients. Compared with arthroscopy, the sensitivity, specificity, and accu- racy of selective magnetic resonance imaging were, respectively, 95.8, 100, and 98% for tears of the lateral meniscus; undefined, 100% and 100% for tears of the posterior cruciate ligament; and 100, 96.9 and 97.3% for tears of the ACL, when that

Arthroscopy, Vol. 4, No. 4, 1988

ligament was well visualized. Our selective se- quence can be performed in 15 min at a cost that is comparable to arthrography, is noninvasive, and re- quires no exposure to ionizing radiation. Selective magnetic resonance imaging can be safe and valu- able adjunct to the clinical evaluation of the knee and an aid to efficient preoperative planning.

Tears of the Meniscus as Revealed by Magnetic Res- onance Imaging. By Ismael Silva, Jr. and Daniel M. Silver. J Bone Joint Surg [Am] 1988;70:199-202.

Forty-four patients who were examined by mag- netic resonance imaging and arthroscopy to detect tears of the meniscus of the knee were studied. Of these patients, 28 (Group I) had had no previous operations on the knee and 16 (Group II) had had a previous operation on the knee that had been per- formed after a meniscal injury. In Group I, 45% were correctly diagnosed by magnetic resonance. If the false-negative results are excluded, a 65% accu- racy rate was achieved. Similarly poor results were found in Group II: 49% were correctly diagnosed and a 55% accuracy rate was achieved after elimi- nating false-negative results.

Prophylatic Knee Braces and Injury to the Lower Ex- tremity. By Thomas G. Grace, Betty J. Skipper, James C. Newberry, Michael A. Nelson, Edward R. Sweetser, and Michael L. Rothman. J Bone Joint Surg [Am] 1988;70:422-7.

Five hundred and eighty high-school football players were studied during two seasons to deter- mine the effect of so-called prophylatic knee braces on the lower extremity. Two hundred and forty- seven athletes who wore single-hinged braces and 83 who wore double-hinged braces were paired for the same season of play with 250 athletes who were similar in height, weight, and playing position but who did not wear braces. The 53 injuries of the knee that occurred in the group who wore single-hinged braces were significantly more frequent (p < 0.001) than those in the matched, nonbraced group. Al- though there were more knee injuries among the participants who were double-hinged braces than in the matched controls who did not wear braces, the increase in the number of injuries was not signifi- cant. A dramatic increase (p < 0.01) in the number of ankle and foot injuries was seen in the athletes who wore braces. These results question the effi- cacy of the braces that were studied and call atten- tion to the potentially adverse effect of the braces on adjacent joints in the ipsilateral limb.