Understanding Custom Knee Replacement and Its Benefits – What Options Do You Have?

Knee Replacement Surgery can be the last hope for patients who have developed severe knee arthritis and no other treatment option seems to work for them. Knee replacement surgery has proven to be an effective treatment for knee arthritis [1]. Traditionally, the implants for knee replacements have been pre-fabricated in a variety of sizes. The most recent development into this specialty is custom knee replacements where the implant is custom made for each patient, guided by CT and MRI.

First, we’ll look at what both a standard knee replacement entails and then a custom knee replacement.

Standard Knee Replacement Surgery

The knee replacement implants have three basic components i.e. the tibial component, the femoral component, and the spacer. When the knee replacement surgery is performed, the tibial component is placed on top of your shin bone while the femoral component fits at the end of your thigh bone. The spacer is actually a plastic component that goes in between the other two metal components. Sometimes, another small piece of plastic is also used in the procedure and it is placed at the back of the kneecap.

When performing a standard knee replacement surgery, the surgeon cuts away a part of the patient’s shin and thigh bones and a metal prosthesis is used as a replacement for those parts of the knee joint. In case of standard surgeries, most of the prostheses used in knee replacements were bought “off the shelf” and have a wide variety of sizes to fit each patient as best as possible.

Custom Knee Replacement Surgery

The primary difference in case of custom knee replacement surgery is that it uses customized knee implants that have been tailored specifically to each patient’s individual needs. Before the surgery is carried out, you undergo a computerized tomography scan which gives a detailed image revealing the bony anatomy of your knee, hip, and ankle.

After the scan, the surgeon uses the information obtained for carefully examining the 3D images of the joints. Eventually, the exact measurements of your knee joint’s size, position, and shape are obtained using computerized technology. These measurements are then used for fabricating a total knee joint prosthesis that fits precisely to your knee’s shape and contour.

Dr. Raj Sinha talks about why he’s elected to use custom knee replacements for his practice below.

What Are Some Proposed Benefits to a Custom Knee Replacement?

The idea behind custom knee replacement implants is to provide:
• Better fitting knee joint prosthesis [3]
• Reduced bone cutting required during the procedure [3]
• The natural shape of the knee and joint line is preserved [7]
• Improved stress distribution as compared to conventional knees [6,8]
• Custom knee replacement is possible for both total and partial knee joint replacement

In addition to the benefits mentioned above, ideally less work needs to be done during surgery for determining proper alignment and ensuring that the knee implant is positioned properly. That’s because the prosthesis has been custom made for you.
Surgeons also believe that it helps to perform the surgery more quickly and there is least tissue disruption in the process [2, 6]. Hopefully, more accurate placement of the implants would allow them to last longer as they won’t wear out too quickly and will offer improved mobility to the patients.

Is It A Reliable Choice to Switch to A Newer System?

As custom total knee replacement is a comparatively newer concept, limited research is available to determine whether or not the custom prostheses offer better results in comparison to the standard “off-the-shelf” knee replacement options. Early studies so far show that the custom knee is comparable to standard knee replacements [3, 6] but there isn’t any concrete data available to reflect that the new system is overall better [3, 4, 5]. Additional long term studies are still being conducted.

Right Device is here to ensure your operative game plan is ready prior to surgery. Sign up today to access our surgery database! Join our Patient Partner Program as well as speak with someone who has had the exact same surgery or with an Orthopedic/Spine Nurse Practitioner or Medical Device Specialist today!

References

1. Choi, Y., & Ra, H. J. (2016). Patient Satisfaction after Total Knee Arthroplasty. Knee Surgery & Related Research, 28(1), 1-15. doi:10.5792/ksrr.2016.28.1.1
2. Slamin, J., & Parsley, B. (2012). Evolution of customization design for total knee arthroplasty. Current Reviews in Musculoskeletal Medicine, 5(4), 290-295. doi:10.1007/s12178-012-9141-z
3. Lee, J., Koh, Y., & Kang, K. (2020). Biomechanical and Clinical Effect of Patient-Specific or Customized Knee Implants: A Review. Journal of Clinical Medicine, 9(5), 1559. doi:10.3390/jcm9051559
4. Schwarzkopf, R., Brodsky, M., Garcia, G. A., & Gomoll, A. H. (2015). Surgical and Functional Outcomes in Patients Undergoing Total Knee Replacement With Patient-Specific Implants Compared With “Off-the-Shelf” Implants. Orthopaedic Journal of Sports Medicine, 3(7), 232596711559037. doi:10.1177/2325967115590379
5. Wheatley, B., Nappo, K., Fisch, J., Rego, L., Shay, M., & Cannova, C. (2019). Early outcomes of patient-specific posterior stabilized total knee arthroplasty implants. Journal of Orthopaedics, 16(1), 14-18. doi:10.1016/j.jor.2018.11.003
6. Haglin JM, Eltorai AE, Gil JA, Marcaccio SE, Botero-Hincapie J, Daniels AH. Patient-Specific Orthopaedic Implants. Orthop Surg. 2016 Nov;8(4):417-424. doi: 10.1111/os.12282. PMID: 28032697; PMCID: PMC6584361.
7. Bali K, Walker P, Bruce W. Custom-fit total knee arthroplasty: our initial experience in 32 knees. J Arthroplasty. 2012 Jun;27(6):1149-54. doi: 10.1016/j.arth.2011.12.006. Epub 2012 Jan 27. PMID: 22285230.
8. Bartel DL, Bicknell VL, Wright TM. The effect of conformity, thickness, and material on stresses in ultra-high molecular weight components for total joint replacement. J Bone Joint Surg Am. 1986 Sep;68(7):1041-51. PMID: 3745241.