Cartilage tumors: evaluation and treatment.

The proper treatment of cartilaginous tumors is dependent on the clinicopathologic and radiologic findings. Enchondroma is a benign tumor that is usually asymptomatic and thus should be treated nonoperatively. Symptomatic enchondromas are often treated by intralesional excision. Intramedullary low-grade chondrosarcoma is a malignant tumor that is usually painful. The treatment of low-grade chondrosarcoma may range from intralesional excision with or without adjuvant therapy to wide excision. Although intralesional excisions have a higher bone and joint preservation rate than wide excisions, they may be associated with a higher local recurrence rate. Intermediate- and high-grade chondrosarcomas are treated with wide excisions. The treatment of these cartilaginous lesions should involve a multidisciplinary team including a musculoskeletal surgeon, a radiologist, and a pathologist.

Orthopedic emergencies in cancer patients.

The most frequent orthopedic emergency in oncology patients is fracture. Stabilization of the entire fractured bone restores function and relieves pain. The site, quality, and extent of the lesion can identify impending fractures that should be stabilized. New methods of pelvic stabilization effectively bypass periacetabular bone deficiency. Spinal cord decompression is important to maintain neurologic function. Advances in segmental fixation of the spine have improved the outcome over what was achieved by radiation alone. Infection is common in neutropenic patients, and should be treated aggressively with antibiotics and drainage of abscesses of the musculoskeletal system. Extravasation of doxorubicin requires prompt local debridement to limit the extent of necrosis propagation. These treatments can effectively improve the quality of life of patients with metastatic cancer. They should be included as "best supportive care" for patients with more than 1 month to live.

Functional and oncological outcome of acetabular reconstruction for the treatment of metastatic disease.

BACKGROUND: Metastatic disease of the acetabulum can be painful and disabling. Operative intervention is indicated for patients who fail to respond adequately to nonoperative treatment. We evaluated the functional and oncological outcome of acetabular reconstruction after curettage for the treatment of refractory symptomatic acetabular metastases. METHODS: Fifty-five patients with metastatic disease of the acetabulum were treated with operative acetabular reconstruction combined with a total hip replacement. The most common primary tumor was carcinoma of the breast (eighteen patients), followed by carcinoma of the kidney (seven patients) and carcinoma of the prostate (seven patients). Forty (73 percent) of the patients presented with multiple skeletal metastases, and eighteen (33 percent) had associated visceral metastases. Twenty-eight (51 percent) had severe pain requiring continuous use of narcotics, twenty-four (44 percent) had moderate pain requiring periodic use of narcotics, and the remaining three (5 percent) had mild pain requiring use of non-narcotic analgesics. Eighteen (33 percent) of the patients could not walk, twenty-three (42 percent) needed a walker or crutches, twelve (22 percent) used a single cane, and two (4 percent) walked without assistive devices. Intralesional curettage of the tumor was performed in all of the patients. Fifty-four of the hips were reconstructed with a protrusio cup and one, with a hemipelvis endoprosthesis. Large defects were reinforced with cement and pin or screw fixation (the modified Harrington technique), which allowed transmission of weight-bearing forces to the remaining intact pelvis. Thirty-six acetabular reconstructions were performed with antegrade pins or cannulated screws; fifteen, with long retrograde screws; and four, with cement. RESULTS: The median period of survival was nine months. Patients with visceral metastases had a median period of survival of three months compared with twelve months for patients without visceral metastases (p < 0.001). Patients with breast cancer presented later in the disease process (p < 0.004) and lived longer than did those with other carcinomas (p < 0.004). Forty-five patients were evaluated three months after reconstruction. Thirty-four (76 percent) of them had relief of pain as determined by decreased use of narcotics. Nine of the eighteen patients who could not walk preoperatively regained the ability to walk. Fourteen of the seventeen patients who originally were able to walk in the community retained that ability. Thirty-three patients were available for evaluation at six months. Twenty-five (76 percent) still had relief of pain, and nineteen (58 percent) were able to walk and function in the community. Overall, fourteen (25 percent) of the fifty-five patients had moderate local progression of the disease, and five of these patients had failure of the fixation. Fourteen early complications developed in twelve (22 percent) of the patients. One patient (2 percent) died perioperatively. CONCLUSIONS: Patients who have acetabular metastases that are refractory to radiation and chemotherapy have a short life expectancy. The early, gratifying results of reconstruction validate the role of operative treatment as a short-term palliative procedure. Protrusio acetabular cups presumably compensate for deficiencies of the medial wall, while cement and pin fixation can be used effectively to reconstruct large defects in the acetabular column and dome. The low rate of fixation failure supports the biomechanical principles of the reconstruction. Generally, the reconstructions are sufficiently durable to exceed the life expectancy of the patients.

Pathomechanics of closed rupture of the flexor tendon pulleys in rock climbers.

We performed a study on twenty-one cadaveric fingers (seven non-paired forearms) to determine the pathomechanics of closed traumatic rupture of the flexor tendon pulleys in rock climbers. The ages of the individuals at the time of death ranged from sixty-one to eighty-four years (mean, seventy-four years). The forearm was placed in a custom-made loading apparatus, and individual fingers were tested separately under simulated in vivo loading conditions. The flexor digitorum superficialis and profundus tendons of each digit were attached to computer-controlled linear stepper motors that were equipped with force transducers, and the force in the tendons was simultaneously increased until avulsion of the tendons or osseous failure occurred. The force in the tendons, the excursion of the tendons, and the force at the fingertip were measured. Damage to the pulleys and bowstringing of the tendons were visualized with a fiberoptic camera. Two fingers fractured before complete rupture of the pulleys. Seventeen of the remaining nineteen fingers sustained an isolated rupture of either the A2 or the A4 pulley as the initial failure event; the A4 pulley ruptured first in fourteen digits (p < 0.001). The A3 and A4 pulleys ruptured simultaneously in one finger, and the A2, A3, and A4 pulleys ruptured simultaneously in another. Subtle bowstringing of the flexor digitorum profundus tendon occurred only after two consecutive pulleys had ruptured (either the A2 and A3 pulleys or the A3 and A4 pulleys). Rupture of all three pulleys was required to produce obvious bowstringing. Isolated rupture of the A2 or A4 pulley did not result in detectable bowstringing of the flexor digitorum profundus tendon. The A1 pulley always remained intact.

Distribution of calcitonin gene-related peptide immunoreactivity in vestibular efferent neurons of the chinchilla.

The distribution of calcitonin gene-related peptide immunoreactivity (CGRPi) within efferent vestibular neurons in the chinchilla was investigated using fluorescent retrograde labeling combined with immunohistochemistry. Efferent vestibular neurons were found bilaterally in clusters: dorsolateral (group E1) and medial (group E2) to the genu of CN VII, as well as ventromedial to the descending CN VII fibers in the parvicellular reticular formation (PCR). The percentage of retrogradely labeled cells containing CGRPi was 77.1 +/- 5.7 for group E1 neurons, 90.3 +/- 3.8 in the E2 region. Among the PCR efferents more then half of the neurons (61.4 +/- 19.9%) expressed CGRP peptide or message. The wide distribution of CGRP among vestibular efferent neurons suggests that CGRP plays an important role in vestibular efferent function. In addition, the differential distribution among the groups of vestibular efferent neurons suggests that efferent modulation of vestibular function is different between the E cell group efferent neurons and the PCR efferent neurons.