Management of Femoral Condyle Insufficiency Fractures Following Total Knee Arthroplasty (FCIF-TKA).

BACKGROUND

Femoral condyle insufficiency fractures following total knee arthroplasty (FCIF-TKA) are rare but significant complications. These fractures, characterized by atraumatic bone insufficiency near the femoral component, present unique challenges in postoperative care, often necessitating femoral component revision.

METHODS

This study retrospectively reviewed 835 primary total knee arthroplasties performed by a single surgeon, identifying six cases of FCIF-TKA. Patient demographics, implant details, radiographic findings, and clinical outcomes were analyzed with up to four years of follow-up. The study aimed to identify risk factors, evaluate management outcomes, and assess pain and mobility improvements.

RESULTS

The incidence of FCIF-TKA was 0.72%, notably higher than previously reported. All cases occurred in female patients with varus deformity, a mean age of 72 years, and a mean BMI of 33.48. Bone mineral density scans revealed osteopenia or osteoporosis in most cases. All patients had stemless posterior-stabilized (PS) femoral implants, with a mean diagnosis time of 17.2 days post-surgery. Conservative management using a hinged knee brace and a 12-week protected weight-bearing protocol proved effective for compliant patients. VAS scores improved from 4.8 at diagnosis to 2.0 at six months and 0.67 at one year. ROM increased from 76.3° postoperatively to 94.2° in one year. One non-compliant patient required revision due to fracture progression. At four years, 83.3% of cases showed implant survivorship without further revision.

CONCLUSIONS

FCIF-TKA appears associated with advanced age, female sex, high BMI, osteoporosis, and severe varus deformities, particularly with stemless PS femoral implants. Preventive strategies may include using cruciate retaining implants and femoral stems to increase the metal-bone surface area over weight-bearing portions of the femoral implant. Conservative management with a hinged knee brace and structured weight-bearing for 12 weeks yields satisfactory pain and ROM improvements at one year, with high survivorship at four years, indicating that immediate revision may not be necessary for all patients.