Are Higher Prices for Larger Femoral Heads in Total Hip Arthroplasty Justified from the Perspective of Health Care Economics? An Analysis of Costs and Effects in Germany

作者：Grunert R; Schleifenbaum S; Moebius R; Sommer G; Zajonz D; Hammer N; Prietzel T^*

来源：Zeitschrift fur Orthopadie und Unfallchirurgie, 2017, 155(1): 52-60.

DOI：10.1055/s-0042-113003

• total hip arthroplasty
• prosthetic head diameter
• costs
• dislocation stability
• wear

Background In total hip arthroplasty (THA), femoral head diameter has not been regarded as a key parameter which should be restored when reconstructing joint biomechanics and geometry. Apart from the controversial discussion on the advantages and disadvantages of using larger diameter heads, their higher cost is another important reason that they have only been used to a limited extent. The goal of this study was to analyse the price structure of prosthetic heads in comparison to other components used in THA. A large group of patients with hip endoprostheses were evaluated with respect to the implanted socket diameter and thus the theoretically attainable head diameter.
Materials and Methods The relative prices of various THA components (cups, inserts, stems and ball heads) distributed by two leading German manufacturers were determined and analysed. Special attention was paid to different sizes and varieties in a series of components. A large patient population treated with THA was evaluated with respect to the implanted cup diameter and therefore the theoretically attainable head diameter.
Results The pricing analysis of the THA components of two manufacturers showed identical prices for cups, inserts and stems in a series. In contrast to this, the prices for prosthetic heads with a diameter of 36-44 mm were 11-50% higher than for 28 mm heads. Identical prices for larger heads were the exception. The distribution of the head diameter in 2719 THA cases showed significant differences between the actually implanted and the theoretically attainable heads.
Conclusion There are proven advantages in using larger diameter ball heads in THA and the remaining problems can be solved. It is therefore desirable to correct the current pricing practice of charging higher prices for larger components. Instead, identical prices should be charged for all head diameters in a series, as is currently established practice for all other THA components. Thus when reconstructing biomechanics and joint geometry in THA, it should be possible to recover not only leg length, femoral offset and antetorsion of the femoral neck, but also to approximately restore the diameter of the femoral head and thereby optimise the functional outcome.