Stress fracture of the hip. An unusual complication of total knee arthroplasty.

Stress fracture of the hip is a rare complication of total knee arthroplasty (TKA). Only eight cases seem to have been reported in the literature. A ninth case is reported in the present study. A 76-year-old obese woman was treated by right TKA for osteoarthrosis with cementing of the tibial component because of insufficient primary fixation. One year after TKA, she complained of tenderness above the right adductor tendons. There was no history of trauma. One month later, bone scintigrams and roentgenograms demonstrated a stress fracture of the femoral neck. Conservative management was successful. Etiologic factors such as rheumatoid arthritis, osteoporosis, steroid medication, or changes in static or dynamic forces of the hip secondary to knee arthroplasty could not be demonstrated in this patient. The increase in activity after TKA may be a factor in the incidence of these stress fractures of the hip. Radionuclear-type bone scan is helpful in diagnosis. The foci of increased isotope uptake are not always seen at the site of the stress fracture and only later visualized by roentgenograms.

Pigmented villonodular synovitis of the hip. A case report and review of the literature.

A 73-year-old patient, whose hip was completely destroyed by pigmented villonodular synovitis, was successfully treated by a total prosthetic replacement of this articulation. The etiopathogenesis of the illness is uncertain. Its' localization in the hip is, fortunately, a rare occurrence. It can be responsible for frequently extensive articular destruction which is even more dramatic when it affects young patients, whose average age is 35. Only early diagnosis permits conservative surgical treatment: total synovectomy associated with curettage of the foyers of osteolysis and their filling with bone grafts. If the destructive lesions are too extensive, an arthrodesis or replacement arthroplasty are proposed.

Sleep apneas and acid esophageal reflux in control infants and in infants with an apparent life-threatening event.

Clinical experience shows that episodes of apnea can occur during regurgitations or vomiting. We questioned whether sleep apneas could be related temporally to documented falls in esophageal pH, when no clinical symptoms of emesis are witnessed. Twenty infants admitted after an apparently life-threatening event ('ALTE') during sleep, but with no clinical symptoms of vomiting or regurgitations at the time of the event, and ten control infants were studied. All infants had occasional episodes of regurgitations. Polygraphic monitoring of state of alertness, cardiorespiratory activity and low esophageal pH was performed continuously during 1 night. The data were analyzed blindly. A total of 334 central and 36 obstructive apneas were monitored, mainly in the ALTE group, during NREM sleep. A total of 116 falls in esophageal pH below 4 units were seen in 18 infants; 50% occurred during wakefulness, and 31% in REM sleep. Arousals or body movements preceded the pH fall in 50% of the cases. Within 5 min following the reflux onset, 18 central apneas (7.2% of the apneas) were seen. There was no correlation between the duration, or the lowest values of esophageal pH measured, and the number or duration of apneas. No obstructive apnea, bradycardia or arousal followed the falls in esophageal pH. Acid esophageal reflux did not play a significant role in the development of apnea in our population.