150 ABSTRACTS

Magnetic Resonance Imaging of the Knee: A Useful Diagnostic Tool. Michael A. Kelly, Howard A. Ki- ernan, Jay A. Kimmel, and Timothy J. Flock. New York, New York, U.S.A.

There have been conflicting reports in the recent literature regarding the value of magnetic resonance (MR) imaging for evaluating internal derangements of the knee. The present study was undertaken to further delineate the role of MR imaging in evalu- ating knee pathology. Fifty-one patients underwent MR scanning before diagnostic arthroscopy per- formed by one of the two senior authors. All of the scans were performed using Tl and T2 equivalent weighted images. Meniscal tears were graded ac- cording to the classification proposed by Dr. D. W. Jackson (1988), with grade III reserved for those tears with increased signal intensity that extended to the articular surface.

The results of the MR imaging were compared with the findings at arthroscopy. For grade III me- niscal tears, the MR had a sensitivity of 90%, spec- ificity of 92%, positive predictive value of 84%, and negative predictive value of 88%. For grade III lat- eral meniscus tears, the MR had a sensitivity of 78%, specificity of lOO%, positive predictive value of lOO%, and negative predictive value of 94%. In evaluating anterior cruciate ligament pathology, MR had a sensitivity of lOO%, specificity of 93%, positive predictive value of 66%, and negative pre- dictive value of 100%. The accuracy of MR was found to be 90% for the medial meniscus, 95% for the lateral meniscus, and 93% for the anterior cru- ciate ligament. In 22 patients, MR was consistent with a grade II tear whereas no clinically significant tear could be found at arthroscopy.

This study provides further evidence that MR im- aging is a highly accurate tool for evaluating menis- cal pathology. Caution must be exercised with grade II abnormalities where the signal does not extend to the articular surface because these may not repre- sent clinically significant tears. The recent confu- sion in the literature regarding the accuracy of MR imaging may be due to the lack of a uniform report- ing system for diagnosing meniscal pathology.

Arthroscopic Endosteal Femoral Fixation for the Re- construction of the ACL. E. Marlowe Goble and David A. McQuire. Anchorage, Alaska, U.S.A.

This paper describes five different methods of mechanical fixation that permit attachment of the

Arthroscopy, Vol. 5, No. 2, 1989

proximal end of the anterior cruciate ligament (ACL) reconstruction within the interior of the dis- tal femur. No femoral incision is required. Entrance into the distal medullary canal of the femur and ul- timately the endosteum is obtained via an arthro- scopic approach through the intercondylar notch. The procedure is monitored arthroscopically and fluoroscopically.

The endosteal fixation devices tested include (a) a threaded delrin screw attached to a graft. A central hex headed driver delivers the assembly into the anterolateral cortex of the femur, and is then re- moved; (b) a similar device to (a), except the center of the threaded screw is hollow, allowing for a “snap-in” device (attached to the ACL graft) to purchase the implanted screw thus eliminating the threading and turning motion required in (a); (c) a cannulated interference screw; (d) a cone-shape ex- panding plug filling a reverse cone-shape endosteal hole drilled by a new internally expanding scissor drill; (e) a tandem tunnel right-angle drill guide, which permits a cross pin to be inserted at right angles to the femoral (or tibial) tunnels.

MTS tensile failure tests reveal yield loads of (a) 2,200 N, (b) 1,000 N, (c) 1,100 N, (d) 1,200 N, and (e) 4,000 N, respectively.

All forms of endosteal fixation described have been thoroughly tested in an animal model for efft- cacy and safety. One hundred fifty human clinical cases using the first and last models described for endosteal fixation have been performed. Follow-up averages 24 months with a maximum follow-up of 4 years. There is no evidence of migration, infection, or other complications.

Endosteal fixation of the origin of the ACL offers a more precise location of purchase (for the ACL) while eliminating extensive exposures for periosteal sites of femoral ACL attachments. Endosteal fixa- tion is required for a total arthroscopic ACL recon- struction.

Arthroscopic Stabilization for Recurrent Shoulder In- stability. Neil James Maki. Thibodaux, Louisiana, U.S.A.

Twenty-one patients with an average follow-up of 44 months (4/88) have undergone arthroscopic cap- sulorrhaphy since 1984 for recurrent anterior shoul- der instability using an intraarticular stapling tech- nique described by Johnson. All of these patients demonstrated Bankart and Hill-Sach lesions at ar- throscopy. Thirteen had documented dislocations

ABSTRACTS 151

and eight had recurrent anterior shoulder sublux- ations.

After surgery, five patients had developed recur- rent instability for a failure rate of 23%. Three of these patients had recurrent symptoms with sports- related activities. Two patients developed recurrent problems with other minimal trauma. Inadequate staple placement may have accounted for one fail- ure. Also during this period, three patients (ex- cluded from this series) underwent immediate open reconstruction because of unacceptable capsular tissue for reattachment or faulty staple placement.

It is recommended that this technique be limited to patients with anterior shoulder instability who understand and are willing to accept a higher recur- rence rate than with conventional surgical recon- struction. The technique should not be used in individuals returning to high-performance athletic activities involving contact. Currently, open treat- ment by conventional surgical procedures is gener- ally preferable.

Arthroscopy of the Painful Dysfunctional Total Knee Replacement. Stephen A. Wasilewski and Uri Frankl. Jerusalem, Israel.

There are few published reports on the use of arthroscopy in the diagnosis and treatment of the painful dysfunctional total knee. Indications of the procedure and results are inconclusive. The pur- pose of this paper is to review our experience with arthroscopy of TKAs. The indications, diagnostic value, and results of therapeutic intervention are studied.

Twelve arthroscopies are reported. Hospital records, operative notes, and x-ray films were re- viewed. In addition, all knees were examined at fol- low-up, which averaged 25 months. Knee ratings were tabulated preoperatively and postoperatively in these patients undergoing operative arthroscopy. All TKAs were semiconstrained prostheses of var- ious designs. Preoperative complaints included pain (10 cases), synovitis (5 cases), poor motion (6 cases), and locking (3 cases). In all but one case (infrapatellar spur), routine roentgenographs failed to show component malalignment, loosening, patel- lofemoral problems, or other etiologies for the pre- operative symptoms. Aspirations failed to demon- strate sepsis in any case. Arthrography was per- formed preoperatively in seven knees and failed to demonstrate loosening in any case. In cases of ar- throfibrosis, a contracted synovial space was uni-

formly demonstrated. The preoperative diagnosis was arthrofibrosis in six knees, unexplained locking in three knees, undiagnosed sepsis in two instances, and impinging infrapatellar spur in one case. Post- operatively, polyethylene fracture of the patellar component was noted in three cases. All cases of arthrofibrosis showed dense synovial adhesions. In 11 of 12 cases arthroscopy successfully diagnosed the cause of the TKA dysfunction. The four cases of diagnostic arthroscopy underwent patellar revi- sion in two cases and complete revision arthro- plasty in two.

Operative arthroscopy was performed in seven knees. One infrapatellar spur was removed with an excellent result. Six knees had synovectomy and lysis of adhesions. The average time from knee im- plantation to surgery was 29.5 months (range 6-60). Lateral retinacular release was routinely per- formed. Postoperatively, continuous passive mo- tion was instituted and continued for 4-6 weeks. Aggressive physical therapy was continued for at least 3 months. The average preoperative motion was 15-48”. Immediately after surgery, the motion averaged 5-104”. At follow-up, motion averaged 7-74”. Results tended to stabilize within 1 year post- arthroscopy. The prearthroscopy Brigham and Women’s knee rating of these seven patients aver- aged 47 (range 25-86). At follow-up examination, the rating averaged 81 (range 60-95).

We conclude that arthroscopic assessment of the painful dysfunctional TKA is indicated for undiag- nosed pain, locking, and synovitis when results of routine evaluation are negative. In addition, arthro- scopic lysis of adhesions diminished pain and im- proved function.

Arthroscopic Classification of Cartilaginous Lesions: Histological and Prognostic Correlation. Joe W. Tip- pett. San Antonio, Texas, U.S.A.

At the present time, classification of cartilaginous lesions is more than purely academic; it is essential in determining the treatment and prognosis of the patient. Previous cartilaginous classifications have been done on specimens obtained either by open arthrotomy or from cadavers. Details of the lesion were often difficult to recognize due to limited ac- cess for complete inspection afforded by an open incision or due to distortion of the dry postmortem cartilage.

One hundred cartiligenous lesions were analyzed under a magnification of 10 by the arthroscope after

Arthroscopy, Vol. 5, No. 2, 1989