Objective Anterior cruciate l igament (ACL) is an important forward stable structure of knees, when its function impaired, the normal mechanical environment of joint will be destroyed. Now, to explore the effect of ACL rupture on the posterior horn of lateral meniscus by measuring biomechanics. Methods Ten specimens of knee joints (5 left and 5 right sides asymmetrically) were donated voluntarily from 10 normal fresh adult male cadavers, aged 26-35 years with anaverage of 31.4 years. The straining of lateral meniscus posterior horn in 10 knee joint specimens before and after resection of ACL were tested when the knee joints loaded from 0 to 200 N at a velocity of 0.5 mm per second at 0, 30, 60, and 90° of flexion and recorded at the moment when the load was 200 N, the ratio of straining before and after resection of ACL were connted. All the specimens were anatomied and observed in general so as to find injuries such as deformation and tearing in lateral meniscus after test. Results The straining of lateral meniscus posterior horn were as follows: intact ACL group, (—11.70 ± 0.95) με at 0° flexion, (—14.10 ± 1.95) με at 30° flexion, (—20.10 ± 1.20) με at 60° flexion, and (—26.50 ± 1.58) με at 90° flexion; ACL rupture group, (—6.20 ± 1.55) με at 0° flexion, (—26.30 ± 1.89) με at 30° flexion, (—37.70 ± 1.64) με at 60° flexion, and (—46.20 ± 2.78) με at 90° flexion. There were significant differences between intact ACL group and ACL rupture group (P lt; 0.05). The straining ratio of the posterior horn of lateral meniscus rupture ACL to intact ACL were 0.53 ± 0.12, 1.90 ± 0.31, 1.88 ± 0.15, and 1.75 ± 0.16 at 0, 30, 60, and 90° of flexion. The lateral meniscus were intact in general and no injuries such as deformation and tearingwere found. Conclusion ACL has a significant biomechanical effect on posterior horn of lateral meniscus. Consequently, the posterior horn of lateral meniscus is overloaded with ACL rupture at 30, 60, and 90° of flexion, and thereby, it will have the high risk of tear.
ObjectiveTo investigate the effectiveness of arthroscopic bipolar radiofrequency energy (bRFE) and lateral partial meniscectomy for lateral meniscus tear and cartilage lesion. MethodsBetween January 2011 and December 2012, 40 eligible patients with lateral meniscus tear and cartilage injury in the lateral knee compartment underwent arthroscopic treatment, and the clinical data were analysed retrospectively. There were 21 males and 19 females, aged 15-65 years (mean, 42.1 years). The left knee was involved in 22 cases and the right knee in 18 cases. The causes of injury included sport injuries in 5 cases and sprain of knee joints in 8 cases, the remaining patients had no history of trauma. The disease duration ranged from 1 month to 10 years (median, 10 months). The Lysholm score and Japanese Orthopaedic Association (JOA) score of the knee were 59.9±8.2 and 69.6±5.3. According to the Outerbridge classification, 2 cases were rated as grade I, 21 cases as grade II, 17 cases as grade III, and 10 cases as grade IV. The scores described by Noyes were 1-16 (mean, 6.52). The Noyes scores were from 1 to 6 points in 20 patients (group A) and 7 to 16 points in 20 patients (group B). During surgery, all patients underwent partial meniscectomy, and radiofrequency-based chondroplasty was used. Knee joint function was assessed using the Lysholm score and JOA score of the knee, and the clinical outcomes between different degrees of cartilage lesions were also compared. ResultsAll incisions healed primarily without complication. All the patients were followed up 8-31 months (mean, 18.1 months). The Lysholm and JOA scores of the knee at last follow-up (92.2±7.2 and 92.9±7.9, respectively) were significantly higher than those at preoperation (P<0.05). There was no significant difference in preoperative Lysholm and JOA scores of the knee between groups A and B (P>0.05), but significance difference was found between 2 groups at last follow-up (P<0.05). ConclusionArthroscopic bRFE and lateral partial meniscectomy have good effectiveness in treating lateral meniscus tear and cartilage lesion. The effectiveness is better in patients with mild cartilage lesion than in patients with severe cartilage lesion.
ObjectiveTo investigate the effectiveness of arthroscopic treatment for combined injury of the posterior horn of the medial meniscus (PHMM) and the anterior horn of the lateral meniscus (AHLM). MethodsBetween September 2009 and December 2012, 36 patients (36 knees) with combined injury of PHMM and AHLM underwent arthroscope surgery. There were 16 males and 20 females with an average age of 47 years (range, 30-64 years), and a median disease duration of 30 months (range, 3 months-9 years). The left knee was involved in 14 cases and the right knee in 22 cases. Two patients had a history of sprain, and other patients had no obvious incentive. The patients had limited activity of the knee in varying degrees; posterior medial tenderness in the medial knee joint space and positive Mcmurray tests were found in all cases, and anterior tenderness in the lateral knee joint space in 26 cases. Effusion of the knee joint occurred in 5 cases. The X-ray and MRI before operation indicated injury of PHMM combined with injury of AHLM in 30 cases and simple injury of PHMM in 6 cases; meniscal cyst was found in 2 cases, and popliteal cyst in 1 case. Partial meniscectomy was used for PHMM, the external-inner suture or partial meniscectomy was used for AHLM. ResultsAll incisions healed primarily with no complication. All cases were followed up 22.5 months on average (range, 10-40 months). At last follow-up, the patients had no pain, weakness, and instability, and tenderness in medial and lateral joint space disappeared. Except 4 patients who had weakly positive Mcmurray test, the results of Mcmurray test were negative in the others. Based on the improved Lysholm classification standard, the results were excellent in 25 cases, good in 8 cases, and fair in 3 cases; the excellent and good rate was 91.7%. ConclusionArthroscopic primary repair of combined injury of PHMM and AHLM can effectively recover the knee function with a better effectiveness.