Migration characteristics and early clinical results of the NANOS® short-stem hip arthroplasty.
BACKGROUND
Femoral short stems promise essential advantages in total hip arthroplasty. Up to now, only short- and midterm clinical studies exist. Data on early stem migration that could predict later aseptic loosening at an early stage are rare. The purpose of this study was to assess migration patterns and clinical outcome 2 years after hip replacement by a metaphyseal anchored cementless short stem.


METHODS
Migration data and clinical results were prospectively assessed in 49 patients. Clinical outcome was measured using the Harris Hip Score (HHS). Migration analyses were performed using the computer-assisted Einzel-Bild-Roentgen-Analyse (EBRA) system.


RESULTS
At 2 years after surgery, none of the implants needed revision, and HHS increased from 47.9 up to 98.1. Of 49 patients, 5 (10%) showed increased vertical stem migration (1.5 mm/2a) that might predict late aseptic loosening. Of 49 stems, 44 (90%) showed stable migration patterns indicating a beneficial long-term outcome.


CONCLUSIONS
Results of this study confirm the excellent clinical data of previous works. Migration patterns strongly suggest that short-stem arthroplasty is not only an innovative but also a reliable strategy in total hip replacement.
Orthopaedic Department, Barmherzige Brüder Hospital, Johannes von Gott-Platz 1, 7000, Eisenstadt, Austria, martin.kaipel@bbeisen.at.
Martin
M
Kaipel
Phillip
P
Grabowiecki
Katrina
K
Sinz
Sebastian
S
Farr
Günter
G
Sinz
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D005271:Femur Head Necrosis / Q000601:surgery*; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery*; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology*; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D017755:Prosthesis Fitting; D011856:Radiographic Image Enhancement