Martin Logan

Tibiofemoral Kinematics Following Successful Anterior Cruciate Ligament Reconstruction Using Dynamic Multiple Resonance Imaging

Background The aim of anterior cruciate ligament reconstruction is to reduce excess joint laxity, hoping to restore normal tibiofemoral kinematics and therefore improve joint stability. It remains unclear if successful ACL reconstruction restores normal tibiofemoral kinematics and whether it is this that is associated with a good result. Study Case series. Purpose To assess the kinematics of the anterior cruciate ligament-reconstructed knee using open-access MRI. Methods Tibiofemoral motion was assessed using open-access MRI, weightbearing through the arc of flexion from 0° to 90° in 10 patients with isolated reconstruction of the anterior cruciate ligament (hamstring autograft) in one knee and a normal contralateral knee. Midmedial and midlateral sagittal images were analyzed in all positions of flexion in both knees to assess the tibiofemoral relationship. Sagittal laxity was also assessed by performing the Lachman test while the knees were scanned dynamically using open-access MRI. Results The amount of excursion between the tibial and femoral joint surfaces was similar between the normal and reconstructed knees, but the relationship of tibia to femur was always different for each position of knee flexion assessed—the lateral tibia being about 5 mm more anterior in the anterior cruciate ligament-reconstructed knees. This anterior tibial position is statistically significantly different at 0° (P < .0006), 20° (P = .0004), 45° (P = .002), and 90° of flexion (P < .006). Anteroposterior laxity was similar between normal and anterior cruciate ligament-reconstructed knees. Conclusion Anterior cruciate ligament reconstruction reduces sagittal laxity to within normal limits but does not restore normal tibiofemoral kinematics despite a successful outcome.

Tibiofemoral Kinematics of the Anterior Cruciate Ligament (ACL)-Deficient Weightbearing, Living Knee Employing Vertical Access Open “Interventional” Multiple Resonance Imaging

Background Our current understanding of tibiofemoral kinematics in the anterior cruciate ligament (ACL)-deficient knee is very limited. Using vertical open-access MRI, it is possible to accurately analyze tibiofemoral motion in patients with isolated rupture of the ACL. Study Prospective cohort study. Purpose To assess if ACL rupture alters normal knee weightbearing kinematics. Methods Tibiofemoral motion was assessed through the arc of flexion from 0 ° to 90 ° in 10 patients with isolated rupture of the ACL in one knee and a normal contralateral knee. Midmedial and midlateral sagittal images were analyzed in all positions of flexion in both knees to assess the tibiofemoral relationship. Results In the lateral compartment of the knee, the tibial plateau is persistently subluxed anteriorly throughout the arc of flexion from 0 ° to 90 ° (flexion facet center to posterior tibial cortex distance of 15.8 mm ± 2.9 in ACL-deficient knees compared to 21.4 mm ± 1.4 in normal knees at 0 ° extension, P< .0001) when compared to normal knees. The medial tibiofemoral relationship is unchanged compared to normal knees. Conclusion Rupture of the ACL changes tibiofemoral kinematics producing anterior subluxation of the lateral tibial plateau. Clinical Significance Altered kinematics may explain, at least in part, the increased incidence of secondary osteoarthritis in patients with ACL rupture.

The Effect of Posterior Cruciate Ligament Deficiency on Knee Kinematics

Background Alteration of the kinematics of the PCL-deficient knee might be a factor in producing the articular damage. Very little is known about the in vivo weightbearing kinematics of the PCL-deficient knee. Hypothesis Isolated rupture of the posterior cruciate ligament alters knee kinematics, predisposing the patient to development of early osteoarthritis. Study Design Case series. Methods Tibiofemoral motion was assessed using open-access magnetic resonance imaging, weightbearing in a squat, through the arc of flexion from 0° to 90° in 6 patients with isolated rupture of the posterior cruciate ligament in one knee and a normal contralateral knee. Passive sagittal laxity was assessed by performing the posterior and anterior drawer tests while the knees were scanned, again using the same magnetic resonance imaging scanner. The tibiofemoral positions during this stress magnetic resonance imaging examination were measured from midmedial and midlateral sagittal images of the knees. Results Rupture of the posterior cruciate ligament leads to an increase in passive sagittal laxity in the medial compartment of the knee (P < .006). In the weightbearing scans, posterior cruciate ligament rupture alters the kinematics of the knee with persistent posterior subluxation of the medial tibia so that the femoral condyle rides up the anterior upslope of the medial tibial plateau. This fixed subluxation was observed throughout the extension-flexion arc and was statistically significant at all flexion angles (P < .018 at 0°, P < .013 at 20°, P < .014 at 45°, P < .004 at 90°). The kinematics of the lateral compartment were not altered by posterior cruciate ligament rupture. The posterior drawer test showed increased laxity in the medial compartment. Conclusion Posterior cruciate ligament rupture alters the kinematics of the medial compartment of the knee, resulting in “fixed” anterior subluxation of the medial femoral condyle (posterior subluxation of the medial tibial plateau). This study helps to explain the observation of increased incidence of osteoarthritis in the medial compartment, and specifically the femoral condyle, in posterior cruciate ligament-deficient knees.

What Really Happens During the Lachman Test? A Dynamic MRI Analysis of Tibiofemoral Motion

Background The Lachman test is the most reliable clinical test for diagnosing rupture of the anterior cruciate ligament (ACL). It is generally believed that the lateral side contributes more than the medial side to anterior tibial translation, but this has never been convincingly proven. The MRI study presented in this article addresses this issue. Hypothesis The lateral side of the ACL-deficient knee contributes more than the medial side to anterior tibial translation. Study Design Prospective cohort study. Methods The Lachman test and the radiologic Lachman test were performed on 10 patients with isolated rupture of the ACL while the knee was scanned dynamically using open-access magnetic resonance imaging. The amount of movement in the midmedial and midlateral compartments of both the contralateral normal knee and the ACL-deficient knee was measured. Results In both normal and ACL-deficient knees, the lateral compartment contributes more than the medial to anterior translation of the tibia. Rupture of the ACL leads to increased laxity in both medial and lateral compartments with a statistically significant greater contribution from the lateral side. Conclusion Rupture of the ACL leads to increased anterior tibial translation coupled with tibial internal rotation.

Repair of Radial Tears and Posterior Horn Detachments of the Lateral Meniscus: Minimum 2-Year Follow-Up

PURPOSE The aim of this study was to show that repair of posterior radial tears and horn detachments of the lateral meniscus is possible and to assess the outcomes. METHODS A retrospective review of 24 patients who had repair of a posterior defunctioning tear of the lateral meniscus combined with anterior cruciate ligament reconstruction was undertaken. Patients completed a follow-up postal questionnaire that included Lysholm, subjective International Knee Documentation Committee (IKDC), and Tegner scoring systems. RESULTS Eight patients had suture repair of a lateral meniscal radial tear. The mean Lysholm, IKDC, and Tegner scores were 86.9 (SD, 11.6), 81.6 (SD, 13.9), and 5.8 (SD, 2.7), respectively, at a mean follow-up of 70.5 months (range, 29.0 to 168.0 months). Subsequent arthroscopy in 2 patients confirmed meniscal healing. Sixteen patients underwent a posterior horn reattachment. The mean Lysholm, subjective IKDC, and Tegner scores were 86.1 (SD, 13.3), 84.3 (SD, 17.0), and 6.5 (SD, 2.1), respectively, at a mean follow-up of 53.6 months (range, 26.0 to 116.0 months). Three patients had subsequent magnetic resonance imaging and/or arthroscopy that indicated meniscal healing. Two further patients had reinjury, and magnetic resonance imaging and/or arthroscopy showed that their repairs had failed. CONCLUSIONS Posterior radial tears that extend to the capsule and posterior horn detachments of the lateral meniscus are frequently amenable to repair. In this study 22 of 24 repairs functioned successfully over a mean follow-up of 58.6 months (range, 26.0 to 168.0 months). LEVEL OF EVIDENCE Level IV, therapeutic case series.

Bioabsorbable versus titanium interference screws with hamstring autograft in anterior cruciate ligament reconstruction: a prospective randomized trial with 2-year follow-up.

PURPOSE The purpose of this study was to prospectively assess the outcome of hamstring autograft anterior cruciate ligament (ACL) reconstruction by use of identically shaped bioabsorbable and titanium interference screws in a randomized trial. METHODS One hundred patients were randomized to have either bioabsorbable or titanium interference screws used for graft tunnel fixation in hamstring autograft ACL reconstruction. Patients were objectively and subjectively assessed preoperatively and 3, 6, 12, and 24 months postoperatively. Radiographs at 12 months postoperatively were also assessed for tunnel width. RESULTS There were no differences in clinical outcome by use of Lysholm and International Knee Documentation Committee scores between the 2 groups at any stage of follow-up to 2 years. Tibial tunnel widths were the same between the 2 groups. There was slightly more tunnel widening in the femur when bioabsorbable interference screws were used. CONCLUSIONS Identically shaped bioabsorbable interference screws and titanium interference screws used for hamstring autograft ACL reconstruction are equally successful up to 2 years postoperatively. LEVEL OF EVIDENCE Level I, prospective randomized trial with more than 80% follow-up.

Is bone tunnel osseointegration in hamstring tendon autograft anterior cruciate ligament reconstruction important

A 27-year-old man underwent anterior cruciate ligament (ACL) reconstruction using 4-strand hamstring autograft with femoral and tibial interference screw fixation. Four weeks after surgery, he developed a discharging hematoma through the graft harvest-tibial tunnel incision, which persisted. The patient required further surgical intervention 7 weeks after the initial surgery. The wound was debrided, the tibial interference screw was removed, and the tibial tunnel was completely cleared of graft remnants. Arthroscopy of the knee was performed, in which the ACL graft appeared healthy and viable. No evidence of intra-articular sepsis was found. Postoperatively, the rehabilitation program was uneventful and, at 36 months, the patient has unrestricted activity and no clinical evidence of excessive ACL laxity. This case supports the importance of marginal articular surface healing of the ACL graft, suggesting that tibial intratunnel healing becomes redundant.