Function after amputation, arthrodesis, or arthroplasty for tumors about the knee

Area of Science:

• Orthopedic Surgery
• Rehabilitation Medicine
• Biomechanical Engineering

Background:

• Malignant skeletal tumors near the knee often necessitate limb-sparing surgery or amputation.
• Functional outcomes and biomechanical efficiency after various knee tumor treatments are not fully understood.

Purpose of the Study:

• To evaluate and compare the functional outcomes and walking efficiency of patients who underwent above-knee amputation, resection arthrodesis, or replacement arthroplasty for malignant knee tumors.

Main Methods:

• A cohort of 22 patients with malignant skeletal tumors adjacent to the knee were analyzed.
• Patients were categorized into three groups based on surgical intervention: above-knee amputation (7), resection arthrodesis (9), and replacement arthroplasty (6).
• Gait speed, oxygen consumption at varying velocities, and functional limitations were assessed and compared between groups and with a normal control group.

Main Results:

• All patient groups walked at a similar, reduced speed (61-66 m/min) compared to normal (80 m/min).
• Walking efficiency, measured by oxygen consumption per body weight per meter, was comparable across different speeds and between patient groups and controls.
• Amputation patients were active but struggled with uneven terrain; arthrodesis patients had limb stability but difficulty sitting; arthroplasty patients were sedentary and limb-protective.

Conclusions:

• Despite different surgical treatments for knee tumors, patients exhibit comparable walking efficiency and oxygen consumption.
• Each treatment modality presents unique functional trade-offs, impacting daily activities and mobility.
• Understanding these functional differences is crucial for optimizing patient rehabilitation and managing expectations after knee tumor treatment.