T. Le Corroller

Biomechanical analysis of the trapeziometacarpal arthroplasty failures.

aaix marseille university, Cnrs, ism, inst movement sci, France; bdepartment of orthopaedics and traumatology, aphm, sainte marguerite hospital, institute for locomotion, 13009, marseille, France; cdepartment of radiology, aphm, sainte marguerite hospital, institute for locomotion, 13009, marseille; dorthopaedic and spine development, 84911, avignon, France; edepartment of hand and reconstruction surgery, aix marseille university, la timone teaching hospital, 13005, marseille, France; funiversity of nice sophia antipolis, Cnrs, ism, inst movement sci, France

Échoanatomie des articulations interphalangiennes distales de la main

PURPOSE To determine normal anatomy of hand distal interphalangeal joints at ultrasonography, and to compare sonographic and anatomic findings. MATERIALS AND METHODS Right hands of three embalmed cadavers and dominant hands of 10 asymptomatic volunteers were evaluated. Distal interphalangeal joints were scanned longitudinally and transversely with a high-frequency linear-array transducer. Sonographic appearances of intra-articular and periarticular structures were analysed in consensus by two musculoskeletal radiologists. Cadaveric dissection provided anatomic comparisons. RESULTS Sagittal and transverse sonographic images enabled good analysis of the extensor tendon, the deep flexor tendon, and the palmar plate. The radial and ulnar collateral ligaments were identified on all coronal scans. Direct visualization of the dorsal triangular structure and of the middle phalanx heads cartilage was possible on longitudinal scans. The dorsal and palmar synovial recesses were better recognized when a small amount of fluid was present. CONCLUSION Ultrasonography with a high-frequency linear-array transducer provides detailed anatomical information about intra-articular and periarticular structures of the hand distal interphalangeal joints.

Biomechanical causes of trapeziometacarpal arthroplasty failure

Abstract Trapeziometacarpal joint prosthesis revision has been widely reported, mainly due to loosening of the trapezium cup. Our hypothesis is that current prostheses do not sufficiently respect the kinematics of this joint. CT scan acquisitions enabled us to determine the position of the first metacarpal relative to the trapezium in three different characteristic postures, in subjects in different stages of arthrosis. A CAD model of a current prosthesis was inserted into the numerical 3D model of the joint under the different postures. In the numerical model, we observe penetration of the cup by the head of the prosthesis. This virtual penetration could, in vivo, amount to overstressing the prosthetic elements, which would lead to loosening of the cup or of the metacarpal stem and luxation of the prosthesis.

Le ganglion de Mondor : mythe ou réalité ?

AIM OF THE STUDY Lymph node involvement is one of the most significant prognostic factors of patients with rectal cancer. Despite major advances in our understanding of the propagation of the rectal cancer, the lymphatic drainage of the rectum remains unclear. This study was designed to assess the number of lymph nodes located around the superior rectal artery and to assess the frequency of Mondors lymph nodes. PATIENTS AND METHODS Twenty-five anatomic subjects were studied. All resections were performed using total mesorectal excision. Lymph nodes were sought in the tissue surrounding the superior rectal artery up to 2 cm under the ending of the superior rectal artery by manual dissection and were submitted for histological examination. The correlation between the number of lymph nodes, and the volume and weight of the tissue surrounding the superior rectal artery was evaluated by non-parametric Spearman test. RESULTS The mean number of lymph nodes per specimen was 2.7 +/- 1.4. The size of the lymph nodes varied between 1 and 7 mm. The lymph nodes were mostly smaller than 3 mm (56%). The number of lymph nodes in the superior rectal mesentery was independent of its volume and its weight. Seven subjects had a Mondors lymph node. The mean size of Mondors lymph node was 3.4 +/- 2.1 cm. CONCLUSIONS The number of NL located around the superior rectal artery is small, varying between 1 and 5. The Mondors lymph node is an inconstant rectal NL. Its only characteristic is its location in the bifurcation or trifurcation of the superior rectal artery.