Posterior cruciate ligament reconstruction. An in vitro study of femoral and tibial graft placement.

We studied posterior cruciate ligament reconstruction in a cadaveric model using two substitutes: a 1-mm diameter flexible cable and an 11-mm diameter Achilles tendon autograft. The thin cable allowed us to study five femoral and five tibial attachments in each knee. A nearly isometric attachment was located after cutting the posterior cruciate ligament while the tibia was reduced with a 100 N anterior force. The five femoral locations studied were the isometric location and four locations centered around this isometric point. The Achilles tendon reconstruction was used with both an isometric and a nonisometric femoral site, allowing us to confirm the results with the wire cable. Posterior motion limits were measured under a 100 N posterior force in the intact, posterior cruciate ligament-deficient, and posterior cruciate ligament-reconstructed knees. We found that the restoration of knee stability in flexion depended strongly on the femoral attachment location. A femoral attachment that was nonisometric by intraoperative measurement, but within the posterior cruciate ligament anatomic footprint, most closely reproduced the intact knee's posterior motion limits. Variations in the tibial attachment site produced only minor changes in the posterior motion limits. We concluded that the proximal-distal location selected for the femoral attachment of a posterior cruciate ligament substitute was particularly important in the restoration of normal posterior motion limits.

Long-term results of total knee arthroplasty in class 3 and 4 rheumatoid arthritis.

One hundred four total knee arthroplasties in 67 patients with class 3 and 4 rheumatoid arthritis were reviewed clinically and radiographically at an average of 12.7 years. The Hospital for Special Surgery knee scores were good to excellent in 84 knees (81%). Seventeen knees (16%) were rated as fair, and three knees (3%) as poor. The average range of motion at follow-up examination was 95 degrees. Six knees failed due to delayed sepsis (4.1%), and two failed due to aseptic loosening. At a follow-up period of 15 years, the survivorship analysis suggests a 91% probability of the arthroplasty remaining functional in situ. Cemented total condylar knee arthroplasties in severe rheumatoid arthritis provide durable pain relief and restoration of function.

Posterior cruciate ligament anatomy and length-tension behavior of PCL surface fibers.

The location of the most nearly isometric region of the PCL has remained a controversial issue. Our data indicate that there is an entire region close to the PCL's proximal edge that is isometric; however, the majority of the PCL is anisometric. This concurs with the work of Grood et al, Ogata and McCarthy, and Sidles et al. However, other authors believe that the posterior-proximal region of the PCL contains the most isometric fibers. These differences could be explained in part through the differences in experimental design. It is important to note that all of these studies placed the most nearly isometric area within the substance of the ligament. What is equally important to understand from all of these studies is the complex length change pattern of fibers comprising the PCL. The function of PCL fibers is not accurately described by the traditional model of an anterolateral bundle and a posteromedial bundle that have reciprocal functions. Further kinematic studies testing potential femoral attachment sites are needed to ascertain the optimal placement for PCL graft substitutes. An earlier study performed in our laboratory suggested that PCl graft placement distal to the isometric region, 4 mm from the proximal edge (within the PCL footprint), provided the most optimal position for correcting abnormal posterior translation after PCL division. We reported that isometric placement at the time of surgery would lead to incorrect positioning of the graft. We are currently investigating alternative graft configurations (eg, two-bundle and multiple-bundle grafts) to determine if PCL function can be reproduced more ideally; however, more analysis is required before definitive recommendations can be made. At present, the ideal operative procedure for PCL reconstruction requires continued biomechanical analysis followed by carefully designed clinical trials.

An intermeniscal fibrous band in a recreational runner.

An intermeniscal fibrous band was found to produce anterior knee pain in a recreational runner. Arthroscopic resection of the band eliminated the symptoms of pain with running. A literature review found no prior reports of this entity. The differential of plica syndrome and Hoffa's disease was reviewed.

Long-term results of the total condylar knee arthroplasty. A 15-year survivorship study.

This study reports the 15-year survivorship of 112 consecutive Total Condylar knee arthroplasties that have been followed since 1974. Two endpoints were chosen for survivorship: (1) Revision attributable to septic or aseptic loosening or malalignment. (2) Revision or roentgenographic evidence of component loosening. Life table analysis reveals a 94.1% clinical survivorship at 15 years, with an 90.9% survivorship when roentgenographic failures are included. There were five revisions: one for infection, one for instability, and three for tibial loosening. In addition, two tibiae and one patella were considered roentgenographically loose, but were not symptomatic. As of May 1992, 34 patients with 48 knees are known deceased, 15 knees are lost to follow-up evaluation, and 49 knees are available for clinical evaluation. Follow-up data was available on 62 knees for greater than 11 years. Ninety-two percent had good or excellent results, with 1.6% fair and 6.5% poor. Average range of motion was 99 degrees. The average Hospital for Special Surgery knee score was 85. Roentgenographic study revealed lucencies around 72% of tibiae, but only two components were loose. There was a correlation between body weight and the presence of radiolucencies, and patients who weighed more than 80 kg had the lowest survivorship at 15 years: 89.2% clinical survival and 70.6% clinical plus roentgenographic survival. Total Condylar knee arthroplasty has a 94.6% clinical survival at 15 years, with predictably good clinical results.