Cemented total-knee arthroplasty in rheumatoid arthritis patients aged under 60 years

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Cemented total-knee arthroplasty in rheumatoid arthritis patients aged under 60 years

Rheumatoid arthritis (RA) is a chronic inflammatory disease that targets joints—with the knee being the most commonly affected. For many RA patients, severe pain, stiffness, and joint damage can make simple tasks like climbing stairs or walking feel impossible. Total knee arthroplasty (TKA), or knee replacement, is a gold-standard treatment for end-stage joint disease—but doctors have long hesitated to recommend it for patients under 60. Why? Fears of higher implant loosening rates and the need for multiple revision surgeries later in life.

A 2019 study from researchers at Peking Union Medical College Hospital in Beijing challenges those concerns. Led by Yu Fan, Zi Wang, and Xi-Sheng Weng, the team evaluated mid-term outcomes of cemented TKA (using bone cement to secure implants) in young RA patients—and whether resurfacing the patella (kneecap) improves results. The findings offer hope for younger RA patients struggling with disabling knee pain.

Who Was in the Study?

The study included 47 RA patients (68 knees) under 60 years old who underwent cemented TKA between 2003 and 2008. To be eligible, patients had:

  • A confirmed RA diagnosis,
  • A cemented condylar prosthesis (16 cruciate-retaining, 52 posterior-stabilized),
  • At least 2 years of follow-up.

Two patients were lost to follow-up, leaving 45 patients (66 knees) for analysis. All received standard post-op care: low-molecular-weight heparin (to prevent blood clots), antibiotics, continuous passive motion therapy, and physical therapy starting the day after surgery.

How Did They Measure Success?

The team tracked clinical and radiological outcomes to gauge TKA’s effectiveness:

  1. HSS Score: A 100-point scale from the Hospital for Special Surgery that rates knee function (pain, mobility, stability). Higher scores mean better function.
  2. VAS Pain: A 0–10 visual analog scale measuring anterior knee pain during stair climbing (0 = no pain, 10 = worst pain).
  3. Range of Motion: Passive knee bending (flexion) and straightening (extension) measured in the supine position.
  4. Radiographs: X-rays assessed implant alignment, bone-cement integration, and “radiolucency” (gaps that signal loosening) using the Knee Society’s system.

What Did They Find?

The results were dramatically positive for young RA patients:

  • Function Improved: The median HSS score jumped from 43.4 (poor function) before surgery to 95.5 (excellent) at last follow-up—a 120% improvement (P < 0.01).
  • Pain Disappeared: The median VAS score plummeted from 7.59 (severe pain) to 0.25 (almost no pain) (P < 0.001).
  • Mobility Got Better: Knee flexion (bending) improved from 101.6° to 110.9°, and extension (straightening) nearly normalized—residual “bend” dropped from 14.8° to 2.5°.

Radiologically, implants stayed stable: Most components were positioned within safe alignment ranges, with minimal radiolucency (no signs of loosening). The median femorotibial angle (knee alignment) remained nearly neutral, which is key for long-term implant survival.

Does Patellar Resurfacing Matter?

A major debate in TKA is whether to resurface the patella (smooth the kneecap). Some surgeons recommend it routinely, but others argue it’s unnecessary. The study found no significant difference in outcomes between patients who had resurfacing (27 knees) and those who didn’t (41 knees). Both groups saw massive improvements in function, pain, and mobility—meaning resurfacing may not be required for every young RA patient.

What About Complications?

Only two minor complications occurred over the median 8.3-year follow-up:

  1. Infection: One knee (1.5%) developed an infection 13 months post-surgery. The implant was removed, antibiotic cement was used, and a revision was done 6 months later.
  2. Nerve Palsy: One knee (1.5%) had temporary peroneal nerve weakness (affecting foot movement). It resolved with conservative care.

No wound problems, implant loosening, or other serious issues were reported.

What This Means for Young RA Patients

For RA patients under 60 with severe knee damage, this study is a game-changer. Cemented TKA delivered excellent clinical and radiological outcomes—even in patients with moderately to extremely active RA (median Disease Activity Score 28: 5.8). The fear of early implant failure? Unfounded in this group.

And for patellar resurfacing? The data suggests it’s not a “must-do”—patients and doctors can decide based on individual needs.

Most importantly, the study sends a clear message: Young RA patients shouldn’t delay TKA if they need it. The benefits—less pain, better function, and a return to daily life—far outweigh the risks.

References

  1. Aaltonen KJ, Virkki LM, Jamsen E, et al. Do biologic drugs affect the need for and outcome of joint replacements in patients with rheumatoid arthritis? A register-based study. Semin Arthritis Rheum. 2013;43:55–62. doi: doi.org/10.1016/j.semarthrit.2013.01.002
  2. Harrysson OL, Robertsson O, Nayfeh JF. Higher cumulative revision rate of knee arthroplasties in younger patients with osteoarthritis. Clin Orthop Relat Res. 2004;421:162–168. doi: doi.org/10.1097/01.blo.0000127115.05754.ce
  3. Zahiri CA, Schmalzried TP, Szuszczewicz ES, Amstutz HC. Assessing activity in joint replacement patients. J Arthroplasty. 1998;13:890–895. doi: doi.org/10.1016/s0883-5403(98)90195-4
  4. Scuderi GR, Bourne RB, Noble PC, et al. The new Knee Society Knee Scoring System. Clin Orthop Relat Res. 2012;470:3–19. doi: doi.org/10.1007/s11999-011-2135-0
  5. Bae DK, Song SJ, Heo DB, et al. Long-term survival rate of implants and modes of failure after revision total knee arthroplasty by a single surgeon. J Arthroplasty. 2013;28:1130–1134. doi: doi.org/10.1016/j.arth.2012.08.021
  6. Nishikawa M, Owaki H, Takahi K, Fuji T. Disease activity, knee function, and walking ability in patients with rheumatoid arthritis 10 years after primary total knee arthroplasty. J Orthop Surg (Hong Kong). 2014;22:84–87. doi: doi.org/10.1177/230949901402200121
  7. Wu Y, Yang T, Zeng Y, et al. Effect of different postoperative limb positions on blood loss and range of motion in total knee arthroplasty: an updated meta-analysis of randomized controlled trials. Int J Surg. 2017;37:15–23. doi: doi.org/10.1016/j.ijsu.2016.11.135
  8. Chen C, Li R. Cementless versus cemented total knee arthroplasty in young patients: a meta-analysis of randomized controlled trials. J Orthop Surg Res. 2019;14:262. doi: doi.org/10.1186/s13018-019-1293-8
  9. Charette RS, Sloan M, DeAngelis RD, Lee GC. Higher rate of early revision following primary total knee arthroplasty in patients under age 55: a cautionary tale. J Arthroplasty. 2019. doi: doi.org/10.1016/j.arth.2019.06.060
  10. Fan Y, Wang Z, Weng XS, et al. Cemented total-knee arthroplasty in rheumatoid arthritis patients aged under 60 years. Chin Med J. 2019;132:2760–2761. doi: doi.org/10.1097/CM9.0000000000000502

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