Segmental total knee arthroplasty after distal femoral resection for tumor.

Sixty-one patients treated with custom-made segmental total knee reconstruction after resection of a primary tumor of the distal femur were reviewed retrospectively. Two types of implants were used: the Walldius hinge prosthesis (Walldius Group, n = 45) and the Kinematic rotating hinge prosthesis (Kinematic Group, n = 16). The mean periods of follow-up observation were 6.4 years for the Walldius Group and 2.3 years for the Kinematic Group. The overall functional results in the Walldius Group were excellent in 7%, good in 26%, fair in 25%, and poor in 42% of the patients. Roentgenographic analyses showed that 50% of the patients had bony resorption, 33% had interface loosening, and 10% had prosthetic stems that were broken at the time of last follow-up evaluation. Forty-two complications occurred in 34 patients who needed additional surgical treatment. Nine of the prostheses in the Walldius Group failed (20%), and 27 of the complications (64%) associated with the use of the Walldius prosthesis occurred in the first three years after implantation. Nineteen Walldius prostheses (42%) were revised or removed for reasons other than local recurrence. The overall functional results of the Kinematic Group were as follows: excellent in 25%, good in 44%, fair in 25%, and poor in 6% of the patients. Roentgenographic analysis showed that there was no change in bone on 81% of the discharge roentgenograms, that there were no radiolucent lines in 87% of the prosthetic replacements, and that there were no radiolucent lines less than 2 mm thick on the roentgenograms. None of the Kinematic rotating hinge prostheses required revision, except one with a patellar button fracture, which was revised without compromising the functional results. Four complications occurred in three patients in the Kinematic Group, and two of them required surgical treatment. The patients with the Kinematic rotating hinge prosthesis had better early functional and roentgenographic results and fewer complications.