The appearance of roofplasties on lateral hyperextension radiographs.

Graft impingement by the roof of the intercondylar notch has recently been implicated as a cause of failure after anterior cruciate ligament reconstruction. Posterior tibial tunnel placement and roofplasties have been advocated to reduce the incidence of graft-roof impingement. Based on our earlier work in this area, we were concerned that lateral hyperextension radiographs, as advocated by Howell and associates to evaluate impingement, did not accurately reflect the extent of roofplasty accomplished intraoperatively. We hypothesized that these radiographs suggested that the grafts were moderately impinged, when, in fact, they were impingement-free. In a cadaver model, we compared radiographs made before and after roofplasty to determine whether there were any resultant changes in the appearance of the intercondylar roof. We found no detectable difference in 70% (14 of 20) of specimens. A second, subtle line superior to the intercondylar line appeared on radiographs in 30% of the specimens. We concluded that postoperative lateral radiographs may fail to show the effect of a roofplasty and can lead to the overdiagnosis of graft-roof impingement.

The effects of dilute epinephrine saline irrigation on the need for tourniquet use in routine arthroscopic knee surgery.

A prospective, randomized, double-blinded study was performed to determine whether dilute epinephrine saline irrigation (1 mg/l) delivered by gravity flow would significantly reduce the need for tourniquet use during routine arthroscopic surgery. One hundred five patients requiring straightforward arthroscopic knee surgery were randomly assigned to either an epinephrine group that received dilute epinephrine irrigation by gravity flow or to a placebo group that received normal saline irrigation by gravity flow. The need for tourniquet use and the tourniquet time, total operative time, and volume of irrigation fluid used were documented and compared between the two groups. A tourniquet was required 50% less often in the epinephrine group than in the placebo group. This difference was found to be statistically significant using the Student's t-test (P < 0.008, alpha < or = 0.05). If a tourniquet was required, the presence of dilute epinephrine in the irrigation fluid did not affect the overall tourniquet time or the ratio of tourniquet time to total operative time. We believe this study proved that dilute epinephrine irrigation is effective in decreasing the need for tourniquet use during routine arthroscopic knee surgery.

Ideal tibial tunnel length for endoscopic anterior cruciate ligament reconstruction.

A successful single-incision endoscopic anterior cruciate ligament reconstruction using bone-patellar tendon-bone autograft requires attention to many technical details. The emphasis of placing the femoral bone plug flush with the opening of the femoral tunnel results in distal shift of the graft. Longer tibial tunnels are required to prevent excessive graft extrusion. The purpose of this study is to compare four direct and indirect measurement methods of tibial tunnel preparation to determine which method can be used to create consistently reproducible tibial tunnels that prevent excessive extrusion or recession of the graft within the tunnel. Tunnels placed at the empiric angles of 40 degrees, 50 degrees, and 60 degrees to the tibial plateau resulted in the incidence of acceptable tibial tunnel lengths of 44%, 83%, and 39%, respectively. Tunnels placed at an angle determined by the formula "N + 7" where 7 degrees is added to the patellar tendon length (N) resulted in acceptable tunnels 89% of the time. Direct measurement methods using the formulas "graft - 50 mm" and "N + 2 mm" resulted in acceptable tibial tunnels of 44% and 100%, respectively. We recommend using the "N + 7" in conjunction with the "N + 2 mm" formula to obtain the advantages of both indirect and direct measurement methods.

Posterior tibial tunnel placement to avoid anterior cruciate ligament graft impingement by the intercondylar roof. An in vitro and in vivo study.

Recent recommendations to "customize" tibial tunnel placement based on the slope of the intercondylar roof and the amount knee hyperextension were derived from a series of cases with graft impingement by the intercondylar roof. We believe that this impingement is caused by anterior placement of the graft and not by variations of notch anatomy among individual patients. In Phase 1 of this study, we drilled tibial tunnels in the posteromedial aspect of the anterior cruciate ligament "footprint" after the ligament was excised in cadaveric knees. We then passed an impingement rod into the back of the knee joint. Lateral radiographs with the knee in hyperextension were taken of each specimen, and the distance between the superior border of the rod and intercondylar roof was measured. In Phase 2, we prospectively obtained lateral hyperextension radiographs of 75 consecutive knees with anterior cruciate ligament reconstructions and evaluated them for graft impingement based on recently published guidelines. In Phase 1, we found no cases of impingement and an average roof clearance of 8.3 mm. In Phase 2, we noted no cases of severe impingement, 3 cases of moderate impingement (4%), and 72 cases (96%) with no impingement. We conclude that posteromedial tibial tunnel placement alone is adequate to avoid graft impingement in almost all patients. Individualized tibial tunnel placement with specialized tibial guidance systems is not necessary.

Cruciate ligament graft intra-articular distances.

Although the length of the anterior and posterior cruciate ligaments have been well characterized in the literature, we are not aware of any studies of the actual length of grafts used in reconstruction of these ligaments. We dissected and measured these distances for 18 cadaver knees of varying size and sex. The precise location of ideal guide pin placement was located based on current recommendations, and the intra-articular graft length was measured with a micrometer by two separate observers. We found that the average intra-articular graft length for the anterior cruciate ligament is 23.56 mm (SD, 0.98 mm), the posterior cruciate ligament is 30.72 mm (SD, 2.61 mm) and the patella tendon graft intertendinous distance is 43.33 mm (SD, 4.21 mm) We conclude that the intra-articular distance for cruciate ligament grafts is less than published values for the ligaments themselves, and that the patella tendon graft is of adequate length to be used for reconstruction of these ligaments.

The anatomy of the human lumbar ligamentum flavum. New observations and their surgical importance.

STUDY DESIGN: An anatomic study was performed to investigate the ligamentum flavum of the human lumbar spine. OBJECTIVES: To describe accurately the interlaminar portion of ligamentum flavum, and to determine if there is an insertion onto the anterosuperior surface of the caudal lamina. SUMMARY OF BACKGROUND DATA: The insertions of the ligamentum flavum onto its adjacent laminas were classically described by Naffzinger. His description has been recounted by others. It has been the authors' observation that there is a slip of inferior ligamentum flavum that inserts onto the anterosuperior surface of the caudal lamina. Review of the literature revealed only anecdotal observations that support the authors' finding. A clear anatomic description of this structure is important to the surgeon who frequently enters the spinal canal at this anatomic site. METHODS: Thirty human lumbar ligamenta flava from six fresh frozen lumbar spines were studied macroscopically, with particular attention paid to the insertions onto the adjacent laminas. RESULTS: The ligamentum flavum consists of a superficial and a deep component. It is continuous in the midline. The superficial ligamentum flavum inserts onto the superior edge and posterosuperior surface of the caudal lamina. The deep ligamentum flavum inserts for a variable distance onto the anterosuperior surface of the caudal lamina. CONCLUSIONS: There is an inferoventral slip of the ligamentum flavum that attaches to the anterosuperior surface of the caudal lamina. This slip is the inferior portion of the deep ligamentum flavum. When the ligamentum flavum's superficial layer is selectively released, the inferoventral slip of the ligamentum flavum's deep layer remains attached to the anterosuperior surface of the caudal lamina and remains between the surgeon and the dura.

Pediatric spine tumors with spinal cord compromise.

Twenty-nine pediatric spine tumor patients with neurologic deficit were reviewed retrospectively to evaluate tumor control, neurologic course, spinal deformity, and response to treatment. Diagnoses included 10 neuroblastomas, nine sarcomas, eight astrocytomas, and two lymphomas. Mean duration of symptoms at presentation was 8 weeks. Mean clinical follow-up was 7 years 4 months, with patient survival of 66% and a local recurrence rate of 34%. Twenty-four percent (seven of 29) of patients recovered minimal neurologic function with treatment, 76% (22 of 29) showed significant recovery, and two thirds (20 of 29) developed spinal deformity. The initial clinical response to chemotherapy appeared to be most pronounced in sarcoma patients (66% positive response).