CEMENTED STEMS

Historically, shoulder arthroplasty began with the use of cemented humeral stems and over time implant design has progressed where cementless (press fit) humeral stems are now more commonly used. Each implant design and implantation fixation/technique has its own inherent issues and risks of complications. Cemented humeral stems result in longer surgical times due to cement placement and make for a more difficult revision for implant extraction. Cementless humeral stems can result in proximal humerus stress shielding and subsequent bone loss depending on method of fixation/ bone ongrowth. At the time this clinical practice guideline was developed, there were no high quality studies which met inclusion criteria to guide evidence-based treatment recommendations.

Uy et al. performed a systematic review and meta-analysis comparing cemented to cementless humeral components and found no significant difference in revision rates (2.3% cementless, 1.8% cemented) when controlling for variable follow up rates. It is unknown if all of the reported revisions were strictly related to complications from the humeral stem. Radiographic loosening was reported 1.4% cemented group and 3.8 cementless group. Wurthel et al. reported 98.0% for cemented and 92.4% for cementless 20-year survivorship for humeral loosening. The authors concluded that both types of fixation provide >90% long term survival. Litchfield et al.⁴⁰ performed a prospective double-blind randomized trial comparing cement to uncemented fixation of humeral stems. The authors found statistically significant improved strength, forward elevation as well as WOOS for the cemented group at two-year follow-up, and significantly less operative time for the uncemented group. There was no difference between groups for ASES or SF-12 at two years. Interestingly, subgroup analysis demonstrated WOOS was significantly different between groups in favor of the cement but women did not demonstrate any difference between groups.

Strength of Evidence (quality of evidence): No reliable evidence

Benefits & Harms:

There are no adverse risks related to the use of either cemented or cementless (press fit) humeral stems.

Outcome Importance:

As with all component related questions/statements, the most important factor is clinical outcome, function, and implant survivorship. The data needs to be strengthened in the literature to provide strong evidence-based recommendations.

Cost Effectiveness/Resource Utilization:

Both implant choices have demonstrated cost effectiveness given the success and longevity of the humeral side of the reconstruction. Determinations still need to be established as to which fixation method will make for more straightforward revision with less risk of proximal humeral bone loss and improved predictable outcomes following revision surgery.

Acceptability:

Both cemented and cementless (press fit) fixation has already been established and has been used clinically for several years. There should be no issues to overcome regarding these treatment methods even with consensus recommendation.

Feasibility:

The consensus statement does not change current clinical practice.

Future Research:

Well-designed high-quality studies are needed to provide data to support an evidence-based guideline regarding cement and cementless humeral stems for shoulder arthroplasty with long term follow-up.  These studies should focus on long term patient reported outcomes as well as humeral related complications.
 

Additional References:    

Uy, M., Wang, J., Horner, N.S., et. al. Cemented humeral stem versus press-fit humeral stem in total shoulder arthroplasty: a systematic review and meta-analysis. Bone Joint J. 2019;101-B(9):1107-1114.

Werthel, J.D., Lonjon, G., Jo, S., Cofield, R., Sperling, J.W., Elhassan, B.T., Long-term outcomes of cemented versus cementless humeral components in arthroplasty of the shoulder: a propensity score-matched analysis. Bone Joint J. 2017;99-B(5):666-673.