Periprosthetic fractures (PPFs) around the knee after total knee arthroplasty (TKA) represent a significant clinical challenge, especially in patients with rheumatoid arthritis (RA). This article explores the fundamental principles, treatment approaches, and overall outcomes for femoral and tibial PPFs in RA patients.

Using the classification system that incorporates prosthetic stability, bone quality, and fracture reducibility ^[1]:

• Type I: Intact bone stock with well-fixed prosthesis.
  • IA: Non-displaced or easily reducible (treated conservatively)
  • IB: Irreducible (requires reduction with internal fixation)
• Type II: Good bone stock with reducible fracture but loose or malpositioned components (requires revision arthroplasty)
• Type III: Compromised bone stock and loose/misaligned components (requires extensive revision surgery)
  This classification aids in selecting appropriate treatment strategies and improving outcomes for PPFs in RA patients.

A 52-year-old female with rheumatoid arthritis (RA), who had undergone right total knee replacement 8 years ago, presented to the emergency department after a slip and fall at home, which resulted in difficulty bearing weight. On examination and radiological imaging, a periprosthetic fracture was identified in the right lateral tibial condyle with anterior and posterior cortex involvement (Fig. 1), and further characterized using CT imaging (Fig. 2). Implant loosening was noted, and damage to the polyethylene insert was present. Based on the discussed classification, this was categorized as a Type III PPF.

The patient had been asymptomatic prior to this event and was on long-term anti-rheumatoid treatment. Preoperative labs and infection markers were within normal limits. Once medically optimized, she was scheduled for staged right knee revision TKA.

She was on oral methotrexate pre-operatively, which was continued post-operatively without interruption.

Surgical Procedure

The patient was placed supine on a radiolucent table. A standard median parapatellar incision was used. The old implant was removed (Fig. 3 and 4), along with all fibrous tissue and residual bone cement. Both medial and lateral collateral ligaments were released. The area was thoroughly irrigated with pulse lavage.

The revision surgery used a tibial wedge system with femoral augments, secured with gentamicin-impregnated cement (Fig. 5 and 6). Although a hinge system was planned, intraoperative findings allowed for the use of a non-hinged constrained prosthesis.

Post-operatively, the patient was started on teriparatide for 6 months to promote bone healing. A long knee brace was applied for 4 weeks. Weight bearing with a walker was initiated immediately, and early knee flexion (up to 30°) and quadriceps strengthening were included in the rehabilitation protocol. Knee flexion was gradually progressed, and upright sitting was allowed after 3 weeks. At the 6-week follow-up, the patient walked independently without assistance, and no extensor lag was observed (Fig. 7 and 8).

At the 1-year follow-up, the patient remained pain-free, fully weight-bearing, and exhibited no extensor lag or instability (Fig. 9 and 10).

PPFs after TKA are relatively rare but clinically significant. Risk factors include poor bone quality—especially from RA, osteoporosis, long-term corticosteroid use, and advanced age [2-17]. Additional contributors include femoral notching, osteolysis, stiff knees, and stress risers like screw holes. Neurologic conditions (e.g., Parkinson’s, epilepsy, ataxia, cerebral palsy) may also increase fracture risk. Although no definitive link has been established between component malalignment and periprosthetic fractures, tibial varus malalignment may contribute to tibial PPFs [18-25]. In this patient, a Type III PPF was caused by a minor fall. Imaging confirmed fracture of the lateral tibial condyle and anterior/posterior cortices with polyethylene wear and component loosening (Fig. 1–4). Prompt preoperative work-up ruled out infection and allowed timely surgery. The Vancouver system classifies this as complex and necessitating revision (Fig. 6). Surgical management addressed implant replacement, polyethylene wear, and fracture stabilization. Early mobilization and structured rehab (Fig. 6-8) were critical to the patient’s recovery. The patient had a history of RA and methotrexate use, both of which impact bone density and healing. Hence, teriparatide therapy was initiated. At one year, radiological follow-up confirmed stable components and full recovery (Fig. 9 and 10). This case reinforces the importance of infection screening, prosthesis evaluation, and multidisciplinary rehabilitation. As TKA rates rise, so will PPFs, especially in immunosuppressed or osteoporotic populations. Continued improvement in implants, techniques, and post-op care are vital for managing such complex cases.

The case of this 52-year-old female demonstrates the complexities of managing a type III PPF, which required revision surgery following trauma. Timely identification, accurate classification, and an individualized surgical approach are essential for achieving optimal outcomes in such cases. Revision TKA can restore function and alleviate pain, but it is crucial to ensure comprehensive postoperative care and rehabilitation to minimize complications and ensure long-term recovery.

The increasing prevalence of TKA in younger and more active patients suggests that the incidence of PPFs will likely continue to rise. RA patients are 3.85 times likely to undergo TKA compared to general population and thus revision TKA rates also increase. This calls for ongoing improvements in surgical techniques, better strategies for managing complex fractures, and more focused research into long-term outcomes for these patients.