Abstract
Introduction
Total Hip Arthroplasty (THA) is currently one of the most widely performed surgical procedures in clinical orthopaedic practice. Despite the recorded number of uncemented implants has steadily increased in recent years, cemented fixation still remains the benchmark in THA, accounting for most of the procedures performed nowadays. The Friendly Short is a novel cemented short-stem that grants a less invasive and more bone conservative approach due to its shortened height and innovative cementing technique. It is indicated to treat elderly patients with the aim of preserving bone diaphysis while decreasing postoperative recovery times. Its instrument set allows to optimize the cement mantle thickness via an improved pressurization and stem centralization system.
Objectives
Aim of this prospective study was to evaluate functional recovery and implant stability after THA with this cemented short-stem.
Methods
Between June 2011 and October 2012, 96 consecutive patients (100 hips) underwent THA with the Friendly Short stem (Lima Corporate). All patients received DELTA-PF cups with UHMWPE cross-linked liners and CoCrMo femoral heads (Lima Corporate). A minimally invasive postero-lateral surgical approach was used in all cases. There were 60 women and 36 men, with a mean age and BMI of 72.6 ± 6.2 (59–85) years and of 26.6 ± 3.9 (18.7–35.6) kg/m2. Most patients were retired (87%) and led a moderately active lifestyle (79%). Underlying pathology was mostly primary coxarthrosis (94%), followed by aseptic necrosis (AVN) (4%) and post-traumatic osteoarthritis (2%). Radiographic and clinical evaluation (Harris Hip Score HHS, Oxford Hip Score OHS) were performed preoperatively, and postoperatively, at 45 days, and at 6, 12, and 24 months.
Results
Mean HHS and OHS improved from 36.0 ± 11.3 (7–57) and 10.9 ± 4.9 (0–24) preoperatively, to 96.4 ± 6.1 (78–100) and 46.5 ± 3.1 (33–48) at 2 years. Most significant improvements were recorded already at 45 days after surgery, with a mean HHS of 78.6 ± 9.9 (27–100) and a mean OHS of 34.0 ± 7.4 (18–48). Despite old age, all patients reported remarkable early recovery, especially in terms of joint functionality [Mean flexion: preoperative 77.7 ± 11.1 (40–90), 101.7 ± 8.9 (70–110) at 45 days] and pain relief [Mean HHS pain domain: preoperative 9.6 ± 4.2 (0–20), 41.4 ± 3.6 (20–44) at 45 days); mean OHS pain sub-domain: preoperative 0.2 ± 0.5 (0–4), 3.4 ± 0.8 (1–4) at 45 days)]. X-rays demonstrated good implant stability thanks to optimal cement fixation; there was only 1 case of non-progressive 1-mm radiolucent lines, but no osteolytic areas, subsidence or loosening were observed. Absence of fatigue fractures in the cement mantle proved that there was good stress distribution. Acetabular cups were all stable: only 1 case of non-progressive 1-mm radiolucent lines was reported, but no case of either sclerosis or osteolysis was observed. No revision or implant failure occurred up to 2-year follow-up.
Conclusions
Clinical and patient-subjective outcomes were very satisfactory, indicating a significant early functional recovery. Although longer follow-up is required, radiographic assessment demonstrated good implant stability already at 2 years as result of this innovative cementing technique.
