Distal Medullary Canal Decompression in Long Stem Hip Replacement in Long Bone Metastasis: Does it Reduce Cardiopulmonary Complications?

BACKGROUND: The femur is the most common long bone affected by metastatic bone disease, with 25% involving the proximal third of the femur. Long stem cemented hip replacement (LHR) is an important option for cases of impending fracture. Pulmonary embolism is a critical complication that can occur. This study evaluates the effectiveness of distal femoral canal decompression in reducing the risk of cardiopulmonary events.

MATERIALS AND METHODS: Thirty two patients with metastatic bone disease of the proximal femur undergoing LHR were recruited and randomized. Conventional technique was used in 16 cases and distal decompression of the medullary canal was carried out for the other 16 patients. The decompression was carried out through a trocar inserted into the distal medullary canal, connected to a vacuum suction. Quantity of emboli was detected through A4 chambers transesophageal echocardiography; the blood pressure and oxygen saturation readings were also recorded.

RESULTS: The decompression group experienced significantly lower Grade 2 and Grade 3 embolic events compared to the conventional group (11 vs. 26), and the duration of the embolic phenomena was shorter. Insertion of the stem and relocating the hip gave the highest amount embolic events. There was a significant drop in systolic blood pressure (SBP) in 12 out of 16 patients (75.0%) in the conventional group and 5 out of 16 patients in the decompression group (31.3%). This is statically significant (P = 0.0124). The average drop in SBP for the conventional group is 45.8 mmHg and the decompression group was 32.9 mmHg. Oxygen saturation remained at above 96% in the decompression group. However, in the conventional group, 25% of the patients had their oxygen saturation drop to below 96% during the insertion of stem and relocation of hip joint.

CONCLUSION: Distal femoral canal decompression is an effective method in reducing the risk of cardiopulmonary embolic events associated with LHR.