Single-Bundle Versus Double-Bundle Anterior Cruciate Ligament Reconstruction: A Comparative 2-Year Follow-up.

PURPOSE: To compare anatomic single-bundle (SB) versus double-bundle (DB) anterior cruciate ligament (ACL) reconstruction and to determine possible differences in clinical outcomes. METHODS: In this prospective randomized study, 64 patients were divided into 2 equal groups. Anatomic SB and DB ACL reconstructions were performed using hamstring tendons. A follow-up examination 2 years after surgery comprised International Knee Documentation Committee (IKDC) 2000 assessment, Laxitester (ORTEMA Sport Protection, Markgröningen, Germany) measurement of anteroposterior translation regarding rotational stability, and radiographic evaluation. Statistical analysis and power calculation were performed (P < .05). RESULTS: We examined 62 patients at a mean of 26 months (range, 23.3 to 32.7 months) after surgery. IKDC subjective and objective scores showed no significant differences when both groups were compared. The Laxitester measurements showed no significant differences regarding anteroposterior translation in the neutral position, internal rotation, and external rotation. However, there was a significant improvement in rotational laxity in external rotation in the DB group (P = .02). No differences were seen between the groups regarding osteoarthritic changes and tunnel widening. CONCLUSIONS: There were no differences in IKDC subjective and objective scores between patients who underwent anatomic SB ACL reconstruction and those who underwent anatomic DB ACL reconstruction. LEVEL OF EVIDENCE: Level I, prospective, randomized controlled clinical trial.

Validation of a measurement device for instrumented quantification of anterior translation and rotational assessment of the knee.

PURPOSE: A test setup for clinical use in the awake and non-anesthetized patient measuring anteroposterior translation and rotation of the knee joint is the subject of validation. METHODS: A measuring device featuring fixation of the foot at 30° of knee flexion with varus/valgus stress posts for the knee was developed. Tibial rotation (external/internal) was imposed with a torque of 2 Nm on the footrest with the ankle locked in dorsiflexion. Anterior translation of the tibia in relation to the femur was measured with a commercially available arthrometer. Measurements were performed in a neutral position, internal rotation, and external rotation. Intrarater and inter-rater reliability was validated in 10 healthy volunteers (Cronbach α). We examined 10 patients with isolated anterior cruciate ligament (ACL) rupture, as well as 10 patients with ACL rupture plus medial instability and 10 patients with additional lateral instability. Side-to-side differences were used for calculation. RESULTS: Comparison of healthy volunteers and subjects with isolated ACL rupture showed significant differences: internal rotation, 0.79 mm and 2.46 mm, respectively (P = .001); neutral position, 0.4 mm and 3.35 mm, respectively (P < .0001); and external rotation, 0.29 mm and 2.5 mm, respectively (P = .003). Significant differences (P = .008) were found between isolated ACL rupture and ACL rupture plus medial instability by use of the ratio of anterior translation in external rotation versus the neutral position. Inter-rater reliability was 0.948 in 10 healthy volunteers and 0.981 in 10 subjects with unilateral ACL rupture. Intrarater reliability in the volunteers was 0.829. CONCLUSIONS: By use of the developed measurement device, the "Laxitester" (ORTEMA Sport Protection, Markgroeningen, Germany), objective differentiation between isolated ACL rupture and ACL rupture plus additional medial instability is possible. Values for anterior translation are reliable and reproducible by different examiners and by the same examiner at different times. CLINICAL RELEVANCE: The Laxitester allows objectification of medial instability in combination with ACL injuries and provides a reference regarding the need for additional medial stabilization. Compared with the isolated measurement of anteroposterior translation, knee instability can be assessed in a more differentiated manner.