title: Clinical outcome of design modifications to the CLS Spotorno Stem in total hip replacement.
abstract: OBJECTIVE
  historically, the original CLS Spotorno Stem has demonstrated excellent survival. The design of this stem was recently modified, resulting in the introduction of a shorter, modular version (CLS Brevius). The purpose of the current study was to evaluate the functional, radiological and survivorship outcomes of the cementless CLS Brevius Stem in a multi-surgeon, single center, consecutive series study at two years post-surgery.
  
  
  METHODS
  the Authors performed 170 total hip arthroplasties in 155 patients using the shorter, triple-taper stem design (CLS Brevius). The patients' diagnoses were primary hip osteoarthritis (OA) in 74.4%, secondary hip OA in 22.6%, and post-traumatic hip OA in 3%. All operations were performed through a mini-posterior approach, with the patient in the lateral decubitus position. The mean follow-up was 32 months (24-44 months). Outcome was assessed using the Harris Hip Score (HHS).
  
  
  RESULTS
  the mean HHS improved from 32 preoperatively to 92 points at final follow-up, while the stem survival rate was 99.4%. Overall, the results were excellent in148 hips (87%), good in 14 hips (8.2%), fair in six hips (3.6%), and poor in two hips (1.2%). Intraoperative complications included a calcar fissure in three hips (1.7%). Correct femoral offset was reproduced in 97% while the planned center of hip rotation was achieved in 98%. Only one hip underwent early stem revision; this was due to major subsidence.
  
  
  CONCLUSIONS
  the modified CLS stem design showed excellent short-term results with a low rate of early postoperative complications. One of the main findings of this study was the high correlation between the planned femoral offset and center of hip rotation and the final radiographic measurements. This high reproducibility, which indicates the ability of the system to restore normal hip anatomy, is indeed due to the extensive modularity that characterizes this stem system. Long-term follow-up studies are necessary to fully compare the outcomes of the new design with its highly successful predecessor.
  
  
  METHODS
  Level IV, therapeutic cases series.
authors.affiliation: Centro Eccellenza Sostituzioni Articolari Toscana (CESAT), Clinica Ortopedica Università di Firenze, Florence, Italy; Fondazione Onlus "...In Cammino...", Fucecchio, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Graceffa
authors.affiliation: The Department of Orthopaedics and Bioengineering, Stanford University School of Medicine, Stanford, USA.
authors.forename: Pier Francesco
authors.initials: PF
authors.lastname: Indelli
authors.affiliation: Centro Eccellenza Sostituzioni Articolari Toscana (CESAT), Clinica Ortopedica Università di Firenze, Florence, Italy; Fondazione Onlus "...In Cammino...", Fucecchio, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Latella
authors.affiliation: Centro Eccellenza Sostituzioni Articolari Toscana (CESAT), Clinica Ortopedica Università di Firenze, Florence, Italy; Fondazione Onlus "...In Cammino...", Fucecchio, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Poli
authors.affiliation: Georgetown University, Washington DC, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Fulco
authors.affiliation: Centro Eccellenza Sostituzioni Articolari Toscana (CESAT), Clinica Ortopedica Università di Firenze, Florence, Italy; Fondazione Onlus "...In Cammino...", Fucecchio, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Marcucci
keywords: CLS; arthroplasty; femoral stem; hip; osteoarthritis