A rare case of Levofloxacin related Iliopsoas and Achilles tendon rupture

Achilles tendon rupture is a well-documented adverse effect of Fluoroquinolones; however, herein we present a case of complete iliopsoas and Achilles, and partial semimembranosus tendon rupture secondary to Levofloxacin.

Macroscopic and microscopic analysis of the structures inserted in the posterior segment of the medial meniscus. How is the semimembranosus tendon involved in ramp lesions?

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.

What Is the Relationship Between the Distal Semimembranosus Tendon and the Medial Meniscus? A Gross and Microscopic Analysis From the SANTI Study Group

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.

Is the plantaris muscle the most undefined human skeletal muscle?

The plantaris muscle is located in the posterior aspect of the superficial compartment of the lower leg, running from the lateral condyle of the femur to the calcaneal tuberosity. Classically, it is characterized by a small and fusiform muscle belly, which then changes into a long slender tendon. From the evolutionary point of view, the muscle is considered vestigial. However, it has recently been suspected of being a highly specialized sensory muscle because of its high density of muscle spindles. It has a noticeable tendency to vary in respect of both origin and insertion. Researchers have published many reports on the potential clinical significance of the muscle belly and tendon, including mid-portion Achilles tendinopathy, ‘tennis leg syndrome’, and popliteal artery entrapment syndrome. The right knee joint area was subjected to classical anatomical dissection, during which an atypical plantaris muscle was found and examined in detail. Accurate morphometric measurements were made. The muscle belly was assessed as bifurcated. Morphologically, superior and inferior parts were presented. There was a tendinous connection (named band A) with the iliotibial tract and an additional insertion (named band B) to the semimembranosus tendon. Both bands A and B presented very broad fan-shaped attachments. The human plantaris muscle is of considerable interest and has frequent morphological variations in its proximal part. Its specific characteristics can cause clinical problems and lead to confusion in diagnosis. More studies are needed to define its actual features and functions.

Popliteus muscle. An anatomical study

Background: The popliteus muscle fulfills a function of rotational stabilizer of the knee. Its particular shape and innervation pattern are the interest of anatomists and surgeons. The aim of this work was characterizing the anatomy and innervation of the popliteus muscle of knees from a sample of mestizo-raced population, predominant in Latin America. Methods: This cross-sectional study was made in 23 knee segments 14 right knees and 9 left knees coming from 14 men and 9 women aged 67 ± 22 years. Results: The popliteus muscle presented a scalene-like triangle shape and its medial base was covered by the superficial expansion of the semimembranosus tendon. The length of its base was 79,2±12,8 mm with a superior and inferior side that measured 58.0±7.4 mm and 101.7±11.7 mm respectively. The popliteus muscle innervation was supplied by the tibial nerve (TN) by the arising of two branches in 22 cases (95.7%). The first branch arose proximal to the inter articular line and presented a length of 91,1 mm. The second branch arose distally to the inter articular line with a length of 48.4±1.3mm. The third was observed in just one case (4.3%) Its length was 108±1.1mm and it arose distally to the inter articular line. Conclusions: The morphological characteristics of the popliteus muscle and its innervation patterns found in our study differ from what was reported in previous studies. The presence of these findings can be considered during the planning of surgical procedures in the posterior aspect of the knee.

A Case Report on Intratendinous Ganglion Cyst of the Semimembranosus Tendon

Ganglion cysts are benign cystic masses that occur in association with musculoskeletal structures. The aetiology of ganglion cysts is controversial; however, it is generally thought to result from myxoid degeneration of connective tissue associated with joint capsules or tendon sheaths, to which the lesions are usually attached. They may occur in any part of the extremities within muscles, menisci, tendons or bones. Hereby, we present a rare case of intra-tendinous location of a ganglion cyst of the semimembranosus tendon occurring within the tendon substance itself. To date, there have only few cases reports in the literature reviewing intra-tendinous ganglion cysts occurred in the lower limbs.