CCD and offset after Nanos short stem in total hip arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomaterials Engineering
• Radiology

Background:

• Short stems for total hip arthroplasty (THA) are a recent innovation aimed at bone and soft tissue preservation.
• The Nanos short stem is one such device designed for minimally invasive approaches and faster patient recovery.
• This study evaluates the radiological outcomes of the Nanos short stem.

Purpose of the Study:

• To assess the radiological changes following the implantation of the Nanos short stem in cementless total hip arthroplasty.
• To evaluate parameters such as subsidence, offset, bone density, and periarticular ossifications.

Main Methods:

• Radiological evaluation of 202 cementless THAs using the Nanos stem in 172 patients.
• Analysis of pre- and post-operative radiographs (AP and lateral) of the proximal femur.
• Assessment of CCD angle, subsidence, offset, osteolysis, bone resorption, bone density, neocortex, and periarticular ossifications.

Main Results:

• One stem revision due to subsidence; two cup revisions for aseptic loosening.
• Two stems showed radiolucent lines at the implant-bone interface.
• Low incidence of measurable subsidence (1.9%) and minor changes in CCD angle and offset.
• Increased bone density in 8.9% and periarticular ossifications in 14 hips.

Conclusions:

• The Nanos short stem allows for correct anatomical reconstruction in total hip arthroplasty.
• Radiological outcomes are comparable to other short stem designs.
• Higher-level evidence from prospective, randomized studies is needed to further evaluate its advantages.