Femur Fracture Following TKR - Wheeless' Textbook of Orthopaedics

- See: TKR Menu

- Discussion:
- known risk factors include notching of the femur, osteoporosis, and excessive polyethylene wear (w/ subsequent osteolytic defect)

- Radiographs:
- often oblique radiographs are needs as well as AP and Lateral views, due to the rotation of the distal fragment;
- lateral radiographs will demonstrate whether the TKR is PCL retaining or sacrificing (the later is more difficult to fix since the intercondylar notch is covered by metal);

- Non Operative Treatment:
- generally non operative treatment is avoided, except in patients with excessive co-morbidity;
- approximately 35% will experience a complication that will require component revision;
- 20% non union rate and 23% rate of malunion;
- permanent knee stiffness is common;
- in the study by Culp et al 1987, one half of patients treated non operatively had increased pain and/or signficant decreased function vs. 13.3% in the control group;

- Retrograde Nailing:
- advantages include ability to exchange the liner (if necessary) and to insert the nail retrograde thru the intercondylar notch - both thru an anterior approach;
- disadvantages
- in the case of a closed box posterior stabilized design retrograde nailing will not be possible;
- even w/ an open box design, the space available for nail passage is limited (usually less than 14 mm), which often means that under-sized nail will have to be used;
- include less than rigid fixation
- possibility of stress risers which may lead to mid shaft femoral frx (as has been reported w/ Seligson nails);

- Fixation Using Richards 90 deg Condylar Screw and Plate:
- see: insertion technique for 95 deg condylar screw
- advantages: allows rigid fixation and early mobilization;
- disadvantages: does not allow for liner replacement and hardware will complicate any future plans for revision;
- if the patient indicates that the TKR was causing pain prior to the fracture, then the need for revision needs to be taken into consideration;
- bone distruction:
- w/ extensive bone destruction is such that large allograft is needed;
- femoral cortical allograft may be applied to the medial femoral cortex and is secured by a laterally applied plate;