Background: Some authors have suggested that the semimembranosus tendon is involved in the pathophysiology of ramp lesions. This led us to conduct a gross and microscopic analysis of the posterior horn of the medial meniscus and the structures inserted on it. Hypothesis: (1) The semimembranosus tendon has a tendinous branch inserting into the posterior horn of the medial meniscus, and (2) the meniscotibial ligament is inserted on the posteroinferior edge of the medial meniscus. Study Design: Descriptive laboratory study. Methods: In total, 14 fresh cadaveric knees were dissected. From each cadaveric donor, a stable anatomic specimen was harvested en bloc, including the medial femoral condyle, medial tibial plateau, whole medial meniscus, cruciate ligaments, joint capsule, and distal insertion of the semimembranosus tendon. The harvested blocks were cut along the sagittal plane to isolate the distal insertion of the semimembranosus tendon on the posterior joint capsule and the posterior horn of the medial meniscus in a single slice. Histological slides were made from these samples and analyzed under a microscope. Results: In all knees, gross examination revealed a direct branch of the semimembranosus and a tendinous capsular branch ending behind the posterior horn of the medial meniscus. This capsular branch protruded over the joint capsule, over the meniscotibial ligament below and the meniscocapsular ligament above, but never ended directly in the meniscal tissue. The capsular branch was 14.3 ± 4.4 mm long (mean ± SD). The direct tendon inserted 11 ± 2.8 mm below the articular surface of the tibial plateau. The meniscotibial ligament inserted on the posteroinferior edge of the medial meniscus, and the meniscocapsular ligament insertion was on its posterosuperior edge. Highly vascularized adipose tissue was found, delimited by the posterior horn of the medial meniscus, meniscotibial ligament, meniscocapsular ligament, and capsular branch of the semimembranosus tendon. Conclusion: In all knees, our study found a capsular branch of the semimembranosus tendon inserted behind the medial meniscus. The meniscotibial ligament was inserted on the posteroinferior edge of the medial meniscus. Histological analysis of this area revealed that this ligament inserted differently from the insertion previously described in the literature. Clinical Relevance: This laboratory study provides insight into the pathophysiology of ramp lesions frequently associated with anterior cruciate ligament injury. To restore anatomy, it is mandatory to reestablish meniscotibial ligament continuity in ramp repairs.
The Fitbone® motorized nail system has been used to correct limb length discrepancies (LLD) for several years. This study focuses on its application in posttraumatic limb lengthening surgery, its outcome and challenges. Materials and methods: A prospective, single center study was conducted between 2010 and 2019 in patients treated with motorized lengthening nails. The inclusion criteria were symptomatic LLD of 20 mm or more. An imaging analysis was done using TraumaCad® software (Brainlab AG, Munich, Germany) to compare frontal alignment angles and limb length discrepancy (LLD) on preoperative and latest follow-up radiographs of the lower limbs. Results: Thirty-four patients were included with a mean age of 28.8 ± 9.7 years, a mean follow-up of 27.8 ± 13 months and a mean hospital stay of 4.4 ± 1.7 days. The mean LLD was 44 ± 18 mm in 29 femoral and 32 ± 8 mm in 4 tibial cases, which was reduced to less than 10 mm in 25/34 (74%) patients. The mean healing index was 84.6 ± 62.5 days/cm for femurs and 92 ± 38.6 days/cm for tibias. The mean time to resume full weight-bearing without walking aids was 226 days ± 133. There was no significant difference between preoperative and final follow-up alignment angles and range of motion. The mechanical lateral distal femoral angle (mLDFA) was corrected in the subgroup of 10 LLD patients with varus deformity of the femur (preoperative 95.7° (±5.0) vs. postoperative 91.5° (±3.4), p = 0.008). According to Paley’s classification, there were 14 problems, 10 obstacles and 2 complications. Discussion: Six instances of locking screw pull out, often requiring reoperation, raise the question of whether a more systematic use of blocking screws that provide greater stability might be indicated. Lack of compliance can lead to poor outcomes, patient selection in posttraumatic LLD patients is therefore important. Conclusion: Limb lengthening with a motorized lengthening nail for posttraumatic LLD is a relatively safe and reliable procedure. Full patient compliance is crucial. In-depth knowledge of lengthening and deformity correction techniques is essential to prevent and manage complications.
Purpose The use of regional anesthesia (RA) for anterior cruciate ligament (ACL) reconstruction reduces morphine consumption, the time spent in the post-anesthesia care unit (PACU) and the hospital readmission rate. However, RA failures due to delays in the induction of anesthesia and its unpredictable success rate (Cuvillon et al.
Objectives: The anatomical description of the posterior segment of the medial meniscus is debatable. The aim of this study was to describe by macroscopic and microscopic analysis the histological nature of the posterior segment of the medial meniscus and the inserted structures (semimembranosus tendon and menisco-tibial ligament) Methods: Fourteen fresh knees were dissected. For each specimen, a stable anatomical piece was taken en bloc, including the medial femoral condyle, the medial tibial condyle, the entire medial meniscus, the cruciate ligaments and the joint capsule, and the distal insertion of the semimembranosus tendon was preserved in its entirety. At this stage, a macroscopic analysis was performed. The blocks were cut along the sagittal plane in order to isolate the distal insertion of the semimembranosus tendon on the posterior joint capsule and the posterior segment of the medial meniscus in the same section. Histological slides were produced from these samples and were microscopically analyzed. Results: In all patients, the macroscopic analysis showed direct semimembranosus tendon expansion and tendinous capsular expansion ending behind the posterior segment of the medial meniscus. It projected onto the joint capsule, on the meniscotibial ligament at the bottom and the meniscocapsular ligament at the top, but never ended directly in the meniscal tissue. On average, the tendon directly inserted 11 ± 2.8 mm below the articular surface of the tibial plateau. The length of the capsular expansion was 14.3 ± 4.4 mm. The meniscotibial ligament was inserted in the posterior-inferior edge of the posterior segment of the medial meniscus and the meniscocapsular ligament in the posterior-superior edge. There was a particularly vascularized adipocyte space delimited by the posterior segment of the medial meniscus, the meniscotibial ligament, the meniscocapsular ligament and the capsular expansion of the semimembranosus tendon. Conclusion: We repeatedly noted capsular expansion of the semimembranosus tendon that inserted behind the medial meniscus. There is an interposing zone between the tendon insertion and the body of the meniscus which creates a fragile zone. The capsular tendon expansion also inserts in the meniscotibial ligaments at the bottom and meniscocapsular ligaments at the top.
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