Upper Extremity

IntroductIon The hand, described as "window to the brain" by Immanuel Kant, [1] is a highly functional unit of the human body. Upper extremity tumors (UETs) may worsen hand functions. Treatment of hand tumors may be complicated, as the hand contains bones, muscles, nerves, and vessels in close proximity. UETs show a large degree of benign behavior. The most common benign tumors encountered during practice are warts, pigmented lesions, ganglion cysts, giant cell tumors of the tendon sheath, and vascular tumors. [2-5] Warts can be treated using cryotherapy, electrocoagulation, laser therapy, and topical drug applications, so they are rarely encountered by the hand surgeon. [6] With other benign tumors, treatment is excision with clear surgical margins. Yet, 1%-2% of primary hand tumors are malignant and these tumors require broader margins and further work-up. [7] There is a relative consensus on the most common malignant skin tumor of the upper extremity as squamous cell carcinoma (SCC). [8,9] Frequencies of the sarcomas differ from each other in different case series, as these tumors are extremely rare. Undifferentiated pleomorphic sarcoma (formerly known as malignan fibrous histiocytoma), liposarcoma, and fibrosarcoma are the most common soft-tissue sarcomas diagnosed in the upper extremity. [10,11] Although malignant tumors are rarely seen in the upper extremity, the rate of malignancy is higher if the patient has certain conditions. Having inherited diseases such Background: Upper extremity tumors (UETs) and their treatment may impair hand functions. Successful prediction of the histopathological examination before surgery will speed up the treatment process. The aim of this study is to determine the frequency and prediction accuracy of tumors encountered in the upper extremity. Patients and Methods: Records of patients operated for UETs between January 2010 and December 2019 were reviewed. Patient gender, initial complaint, the anatomic region of the tumor, comorbidities predisposing to malignancy, method of biopsy, preliminary diagnosis and predicted malignancy status after initial examination, definitive histopathological diagnosis, and malignancy status were extracted retrospectively. Prediction accuracy rates were calculated for each tumor group. Chi-square analysis was used for comparative analysis of prediction accuracy rates between cutaneous pigmented versus soft-tissue lesions and patients with/without a predisposition to malignancy. Results: The study included 416 pathological specimens from 290 patients. The most common tumors of the upper extremity were lipoma (20%), ganglion cyst (10.1%), and epidermoid cyst (5.8%). After pathological evaluation, 23 specimens were diagnosed as malignant (5.5%) and 32 specimens as premalignant (7.7%). The prediction of malignancy status was accurate in 390 specimens (93.7%). Soft-tissue sarcomas (67.7%) and vascular lesions (58.1%) have the lowest accuracy rates among all tumors. Conclusion: Definitive diagnosis and malignity status can be predicted after the initial examination in the majority of the cases. However, imaging studies or incisional biopsies are needed for soft-tissue sarcomas, vascular tumors, or tumors of patients with a predisposing condition to malignancy.

The aim of this study was to apply models derived from the robotics field to evaluate the human upper-limb force generation capacity. Four models were compared: the force ellipsoid (FE) and force polytope (FP) based on unit joint torques and the scaled FE (SFE) and scaled FP (SFP) based on maximum isometric joint torques. The four models were assessed from four upper-limb postures with varying elbow flexion (40°, 60°, 80° and 100°) measured by an optoelectronic system and their corresponding isometric joint torques. Ten subjects were recruited. Three specific ellipsoids and polytopes parameters were compared: isotropy, principal force orientation and volume. Isotropy showed that the ellipsoids and polytopes were elongated. The angle between the two ellipsoids main axis and the two polytopes remained low but increased with the elbow flexion. The FE and FP volumes increased and those of SFE and SFP decreased with the elbow flexion. The interest and limits of such models are discussed ...

Transfers are one of the most physically demanding wheelchair activities. The purpose of this study was to determine if using proper transfer skills as measured by the Transfer Assessment Instrument (TAI) is associated with reduced loading on the upper extremities. Twenty-three wheelchair users performed transfers to a level-height bench while a series of forces plates, load cells, and a motion capture system recorded the biomechanics of their natural transferring techniques. Their transfer skills were simultaneously evaluated by two study clinicians using the TAI. Logistic regression and multiple linear regression models were used to determine the relationships between TAI scores and the kinetic variables on both arms across all joints. The results showed that the TAI measured transfer skills were closely associated with the magnitude and timing of joint moments (P < .02, model R(2) values ranged from 0.27 to 0.79). Proper completion of the skills which targeted the trailing arm...