Biomechanical Study of Different Femoral Fixation Devices in the Reconstruction of the Medial Patellofemoral Ligament in Porcine Knees.

Objective To evaluate different femoral fixation devices for medial patellofemoral ligament reconstruction and compare their effectiveness regarding fixation strength up to failure in porcine knees. Methods Thirty porcine knees were used, divided into three groups of 10 knees. The removed grafts were dissected from the extensor tendons of porcine feet. In each group, the graft was fixed to the femur with an interference screw, an anchor, or adductor tenodesis. The three methods were subjected to biomechanical tests using a universal Tensile testing machine at a speed of 20 mm/minute. Results The highest average linear resistance under lateral traction occurred in group 1, "screw fixation" (185.45 ± 41.22 N), followed by group 2, "anchor fixation" (152.97 ± 49, 43 N); the lower average was observed in group 3, "tenodesis fixation" (76.69 ± 18.90 N). According to the fixed error margin (5%), there was a significant difference between groups ( p < 0.001); in addition, multiple comparison tests (between group pairs) also showed significant differences. Variability was small, since the variance coefficient was lower than 33.3%. Conclusion Interference screws in bone tunnels and mountable anchors fixation with high resistance wire are strong enough for femoral fixation in porcine medial patellofemoral ligament reconstruction. Adductor tenodesis, however, was deemed fragile for such purpose.

Assessment of the alpha angle and mobility of the hip in patients with noncontact anterior cruciate ligament injury.

PURPOSE: To evaluate the alpha angle of the hip in patients with noncontact anterior cruciate ligament (ACL) injury and compare it with patients without injury. In addition, external and internal rotation of the hip was assessed and correlated with the alpha angle. METHODS: The alpha angle of the ipsilateral hip was assessed in 41 subjects with non-contact ACL tear and compared with 39 subjects with no tear. The external and internal rotation of the ipsilateral hip was also evaluated. RESULTS: The alpha angle was larger in subjects with noncontact ACL injury. The mean was 70.31° (±13.92°) compared with 58.55° (±13.95°) in the control group (p < 0.001). The groups were similar when considering the external, internal, and sum of rotation of the ipsilateral hip. There was no correlation between the alpha angle and decreased rotational range of motion of the hip in either group (p > 0.05). CONCLUSION: Patients with noncontact ACL injury presented a greater alpha angle when compared with the group without tear. There was no difference in the rotational mobility of the hip between groups, nor was there a correlation between the increase in the alpha angle and the decrease in the rotational mobility of the hip.

Femoral tunnel enlargement after anterior cruciate ligament reconstruction using RigidFix compared with extracortical fixation.

PURPOSE: The aim of this study was to compare femoral tunnel enlargement after anterior cruciate ligament (ACL) reconstruction surgery using hamstring autograft tendons fixed by bioabsorbable femoral trans-tunnel pins with that in patients in which the graft was fixed with extracortical fixation. METHODS: Forty-three patients were randomly selected from our database and included in the study. Femoral tunnel diameter was measured by computed tomography in 20 patients who underwent ACL reconstruction via anteromedial portal technique using autologous quadruple hamstrings, fixed with two bioabsorbable trans-tunnel pins, RigidFix, on the femoral side and compared with 23 patients in whom extracortical fixation, EndoButton CL, was used. The diameter of the femoral tunnel was measured at a distance of 5 mm from the tunnel entrance and at the largest diameter along the tunnel axis. Data were compared with the diameter of the drill used during surgery. Clinical evaluation was performed using the Lysholm score, IKDC subjective score and anterior knee laxity measurements. RESULTS: Femoral tunnel enlargement 5 mm from the entrance and at the largest diameter was greater in the RigidFix group than the EndoButton group. There were no significant differences between the two groups regarding age, gender, post-operative Lysholm score, IKDC subjective score or knee laxity measurements. CONCLUSION: The present study showed greater enlargement of the femoral bone tunnel when a bioabsorbable trans-tunnel pin system was used with the medial portal technique when compared to extracortical fixation. These findings confirm that femoral tunnel widening should be considered when RigidFix was used in ACL reconstruction by anteromedial portal technique. LEVEL OF EVIDENCE: III.

Range of motion and radiographic analysis of the hip in patients with contact and non-contact anterior cruciate ligament injury.

PURPOSE: To compare the range of motion (ROM) and radiography of the hip joints in male patients with contact anterior cruciate ligament (ACL) injury and non-contact ACL injury. METHODS: ROM of the ipsilateral hip was evaluated in 35 male patients with contact ACL injury (contact group) and compared to that of 45 male patients with a non-contact ACL injury (non-contact group). Radiographic evaluation of hip joints was also performed to assess the presence of cam and pincer-type deformity . RESULTS: ROM of the hip joint was statistically higher in patients with contact ACL injury. The average sum of hip rotation in the non-contact group was 66.1 ± 8.4° compared to 79.4 ± 10.6° for the contact group (p < 0.001). Seventy-seven per cent of patients in the non-contact group had a sum of hip rotation <70° and 93 % had <80°, compared to17.1 and 42.9 % in the contact group (p < 0.001). Prevalence of cam or pincer deformity was similar in the groups. Cam or pincer deformity was not more frequent in patients with limited ROM of the hip. CONCLUSION: Individuals with contact ACL injury had greater ROM of the hip joints than those with non-contact ACL injury. The presence of cam or pincer deformity was similar in both groups and was not related to decreased ROM of the hip joints. These findings may assist the surgeons to identify new risk factors for non-contact ACL injury and, additionally, develop prevention program of injury. LEVEL OF EVIDENCE: III.

TREATMENT OF OSTEOCHONDRAL LESIONS OF THE TALUS BY MEANS OF THEARTHROSCOPY-ASSISTED MICROPERFORATION TECHNIQUE.

OBJECTIVE: To evaluate patients affected by osteochondral fractures of the talus who were treated surgically by means of arthroscopy-assisted microperforation. METHODS: A retrospective study was carried out on 24 patients with osteochondral lesions of the talus who underwent microperforation assisted by videoarthroscopy of the ankle. They were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) score system before and after the operation. RESULTS: There were 19 men and 5 women, with a mean age of 35.3 years (minimum of 17 years and maximum of 54 years). The minimum follow-up was two years (maximum of 39 months). All the patients showed an improvement in AOFAS score after surgery, with an average improvement of around 22.5 points. CONCLUSION: Videoarthroscopy-assisted microperforation is a good option for treating osteochondral lesions of the talus and provides good functional results.