Albert W. Pearsall

Chondrocyte Viability in Refrigerated Osteochondral Allografts Used for Transplantation Within the Knee

Purpose To evaluate cell viability and matrix characteristics of refrigerated osteochondral allografts implanted up to 44 days after harvest. Methods Sixteen refrigerated allografts underwent histologic and ultrastructural examination and fluorescence excitation analysis prior to implantation. The average size of the graft implanted was 6.2 cm2 (± 3.4 cm2). Refrigerated allografts averaged 30 days (range, 17 to 44 days) from donor expiration to implantation. Nine specimens underwent cell viability testing. The percent viability of refrigerated allografts prior to implantation averaged 67%. Results No significant correlations were noted between histologic score, electron microscopy score, matrix staining percent (MSP) score, and viability. When time to implantation was assessed, an inverse correlation was noted with MSP score (r= .539) (P< 0.05), indicating less matrix staining in grafts refrigerated longer after harvest. Conclusion The current data indicate that refrigerated osteochondral allografts can be maintained for up to 44 days with average chondrocyte viability of 67%.

An in vitro analysis of patellofemoral contact areas and pressures following procurement of the central one-third patellar tendon

Patients have complained of pain after the use of the central one-third patellar tendon for reconstruction of the anterior cruciate ligament-deficient knee. This study investigated the effect on patellofemoral contact areas and pressures of harvesting the central 10 mm of the patellar tendon in five cadaveric knees. Isometric quad riceps forces were applied to produce approximately 30% of reported maximum voluntary extension mo ments at the knee. Using Fuji pressure-sensitive film, measurements were recorded for three states: the normal knee, after the graft removal, and after the tendon was closed. Contact areas and pressures were measured at 20°, 30°, 60°, and 80° of knee flexion in each specimen. Tests of the reproducibility of our meth ods were performed. Average patellofemoral contact areas for three states ranged from 1.6 cm2 at 20° of knee flexion to 3.0 cm2 at 60°. The average patellofemoral contact pressures ranged from 1.9 MPa at 20° of knee flexion to 3.0 MPa at 30°. At each flexion angle there were no significant differences in average patellar contact area or pressure for the three states (P < 0.05). These results suggest that neither harvesting the central 10 mm of the patellar tendon, nor closing the gap, significantly alters patello femoral contact area or pressure.

In vitro study of knee stability after posterior cruciate ligament reconstruction

The effect of reconstructing the posterior cruciate ligament on anteroposterior laxity of the knee was evaluated in 7 cadaveric knees. A bone-patellar tendon-bone graft was used. Femoral pilot holes were drilled to locate the most isometric sites for attachment of the graft to the femur using an isometer. A tension of 89 N was set in the graft using a tensiometer with the knee in 90 ° flexion while applying an anterior drawer force of 156 N to the tibia. Posterior displacement of the knee was measured in 15 ° increments from 0 ° to 90 ° in the intact knee, in the knee with the posterior cruciate ligament transected, and after reconstruction of the posterior cruciate ligament in response to 100 N of posteriorly applied force. Graft tension was nearly constant between 0 ° and 90 ° flexion, indicating the grafts to be isometric. The reconstruction reduced posterior translation of the tibia in the posterior cruciate ligament excised knee at all angles of flexion; the differences were statistically significant. The reconstruction returned posterior translation to levels not significantly different from those of the intact knee between 0 ° and 45 ° flexion but not in the greater angles of flexion tested.

Knee and Ankle Position, Anterior Drawer Laxity, and Stiffness of the Ankle Complex

CONTEXTnAnterior drawer testing of the ankle is commonly used to diagnose lateral ligamentous instability. Our hypothesis was that changing knee and ankle positions would change the stability of the ankle complex during anterior drawer testing.nnnOBJECTIVESnTo assess the effects of knee and ankle position on anterior drawer laxity and stiffness of the ankle complex.nnnDESIGNnA repeated-measures design with knee and ankle position as independent variables.nnnSETTINGnUniversity research laboratory.nnnPATIENTS OR OTHER PARTICIPANTSnBilateral ankles of 10 female (age = 19.8 +/- 1.1 years) and 10 male (age = 20.8 +/- 1.2 years) collegiate athletes were tested.nnnINTERVENTION(S)nEach ankle complex underwent loading using an ankle arthrometer under 4 test conditions consisting of 2 knee positions (90 degrees and 0 degrees of flexion) and 2 ankle positions (0 degrees and 10 degrees of plantar flexion [PF]).nnnMAIN OUTCOME MEASURE(S)nRecorded anterior laxity (mm) and stiffness (N/mm).nnnRESULTSnAnterior laxity of the ankle complex was maximal with the knee positioned at 90 degrees of flexion and the ankle at 10 degrees of PF when compared with the knee positioned at 0 degrees of flexion and the ankle at 10 degrees or 0 degrees of PF (P < .001), whereas ankle complex stiffness was greatest with the knee positioned at 0 degrees of flexion and the ankle at 0 degrees of PF (P < .009).nnnCONCLUSIONSnAnterior drawer testing of the ankle complex with the knee positioned at 90 degrees of flexion and the ankle at 10 degrees of PF produced the most laxity and the least stiffness. These findings indicate that anterior drawer testing with the knee at 90 degrees of flexion and the ankle at 10 degrees of PF may permit better isolation of the ankle capsuloligamentous structures.

Transfer of the Latissimus Dorsi as a Salvage Procedure for Failed Debridement and Attempted Repair of Massive Rotator Cuff Tears

Seven patients who had a previously failed attempt at debridement and repair of a massive rotator cuff tear were managed with latissimus dorsi transfer. Patient age averaged 63 years and average follow-up was 31 months. All patients were evaluated with shoulder radiographs, Constant and Murley Scores, UCLA Shoulder Score, visual analog pain score, range of motion, and the Short Shoulder Form. Modest improvement was noted in forward flexion and abduction. Significant improvement was noted in shoulder function. Transfer of the latissimus dorsi as salvage for a previously failed repair of a massive rotator cuff tear is effective in providing pain relief and improving shoulder function.

Joint Stability Characteristics of the Ankle Complex After Lateral Ligamentous Injury, Part I: A Laboratory Comparison Using Arthrometric Measurement

CONTEXTnThe mechanical property of stiffness may be important to investigating how lateral ankle ligament injury affects the behavior of the viscoelastic properties of the ankle complex. A better understanding of injury effects on tissue elastic characteristics in relation to joint laxity could be obtained from cadaveric study.nnnOBJECTIVEnTo biomechanically determine the laxity and stiffness characteristics of the cadaver ankle complex before and after simulated injury to the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) during anterior drawer and inversion loading.nnnDESIGNnCross-sectional study.nnnSETTINGnUniversity research laboratory.nnnPATIENTS OR OTHER PARTICIPANTSnSeven fresh-frozen cadaver ankle specimens.nnnINTERVENTION(S)nAll ankles underwent loading before and after simulated lateral ankle injury using an ankle arthrometer.nnnMAIN OUTCOME MEASURE(S)nThe dependent variables were anterior displacement, anterior end-range stiffness, inversion rotation, and inversion end-range stiffness.nnnRESULTSnIsolated ATFL and combined ATFL and CFL sectioning resulted in increased anterior displacement but not end-range stiffness when compared with the intact ankle. With inversion loading, combined ATFL and CFL sectioning resulted in increased range of motion and decreased end-range stiffness when compared with the intact and ATFL-sectioned ankles.nnnCONCLUSIONSnThe absence of change in anterior end-range stiffness between the intact and ligament-deficient ankles indicated bony and other soft tissues functioned to maintain stiffness after pathologic joint displacement, whereas inversion loading of the CFL-deficient ankle after pathologic joint displacement indicated the ankle complex was less stiff when supported only by the secondary joint structures.

Osteoarticular autograft and allograft transplantation of the knee: 3 year follow-up.

Between 1998 and 2001, a total of 48 patients underwent autologous or allograft osteoarticular transplantation with a minimum follow-up of 24 months. Nineteen patients underwent concomitant procedures. Average patient age was 46 years. Graft area averaged 4.8 cm2 (range, 0.2-21.6 cm(2)). Grafts implanted included 24 autografts, 12 refrigerated allografts, and 12 frozen allografts. Average follow-up was 37.1 months (range, 24-63 months). Postoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Knee Society Score (KSS), and pain scores improved significantly. Age <35 years and male gender was associated with a positive outcome. There was no significant difference in improvement between autograft and allograft groups. Nine patients, considered failures, underwent total knee arthroplasty and data analysis. No significant relationship was noted for any variable. Eighty-one percent of grafts are still functioning >3 years after transplantation.

Joint Stability Characteristics of the Ankle Complex in Female Athletes With Histories of Lateral Ankle Sprain, Part II: Clinical Experience Using Arthrometric Measurement

CONTEXTnThis is part II of a 2-part series discussing stability characteristics of the ankle complex. In part I, we used a cadaver model to examine the effects of sectioning the lateral ankle ligaments on anterior and inversion motion and stiffness of the ankle complex. In part II, we wanted to build on and apply these findings to the clinical assessment of ankle-complex motion and stiffness in a group of athletes with a history of unilateral ankle sprain.nnnOBJECTIVEnTo examine ankle-complex motion and stiffness in a group of athletes with reported history of lateral ankle sprain.nnnDESIGNnCross-sectional study.nnnSETTINGnUniversity research laboratory.nnnPATIENTS OR OTHER PARTICIPANTSnTwenty-five female college athletes (age = 19.4 ± 1.4 years, height = 170.2 ± 7.4 cm, mass = 67.3 ± 10.0 kg) with histories of unilateral ankle sprain.nnnINTERVENTION(S)nAll ankles underwent loading with an ankle arthrometer. Ankles were tested bilaterally.nnnMAIN OUTCOME MEASURE(S)nThe dependent variables were anterior displacement, anterior end-range stiffness, inversion rotation, and inversion end-range stiffness.nnnRESULTSnAnterior displacement of the ankle complex did not differ between the uninjured and sprained ankles (P = .37), whereas ankle-complex rotation was greater for the sprained ankles (P = .03). The sprained ankles had less anterior and inversion end-range stiffness than the uninjured ankles (P < .01).nnnCONCLUSIONSnChanges in ankle-complex laxity and end-range stiffness were detected in ankles with histories of sprain. These results indicate the presence of altered mechanical characteristics in the soft tissues of the sprained ankles.

The Effect of Isometric Graft Posterior Cruciate Ligament Reconstruction on Anterior Tibial Translation

Eight fresh-frozen cadaver knees were studied to evaluate whether an isometrically placed posterior cruciate ligament (PCL) graft restores normal posterior tibial translation without overconstraining anterior tibial translation. Each knee was tested with a three-axis load cell in the intact state, after PCL sectioning, and after PCL reconstruction. After PCL reconstruction, posterior tibial displacement was restored to values observed in the intact state for all flexion angles except 60 degrees and 90 degrees. Anterior tibial translation was not significantly changed for any of the three states. These results indicate isometric reconstruction of the PCL significantly reduces posterior tibial translation without overconstraining anterior tibial translation.