https://doi.org/10.1177/1120700018813209 HIP International 2018, Vol. 28(2S) 21–27 © The Author(s) 2018 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1120700018813209 journals.sagepub.com/home/hpi HIP HIP International Introduction Conventional femoral stems are known to provide a high rate of satisfactory performance at long-term follow-up in patients who undergo this type of surgery for primary or post-traumatic osteoarthritis and avascular necrosis. 1–3 These successful long-term results have led to a steady increase in primary total hip arthroplasty (THA) over the past 3 dec- ades. 4 However, traditional long femoral stems may have more consequences related to stress shielding, thigh pain and cortical hypertrophy. 5–7 Additionally, surgeons should always give consideration to future revision THA, especially for young and active patients. 8 Short stems were first designed by Judet and Judet 9 in the 1940s and later developed with the purpose of reducing the risk of stress-shielding, thigh pain and cortical hypertrophy and of preserving more bone stock for future revisions, optimising the proximal load transfer and avoiding proximal-distal mismatch. Biomechanical studies showed that these metaphyseal-fitting stems exhibit good fixation achieving durable bone ingrowth and good Stemless hip arthroplasty versus traditional implants: a comparative observational study at 30 months follow-up Giandomenico Logroscino, Fabrizio Donati, Vincenzo Campana and Michela Saracco Abstract Introduction: The aim of this retrospective case-control study is to evaluate clinical and radiographic results of short stems compared with traditional hip prostheses. Methods: 46 short stems (SS) and 50 traditional stems (TS) were selected. All the stems were implanted by the same surgeon using posterior approach because of primary osteoarthritis, post-traumatic osteoarthritis and avascular necrosis. All the patients were compared clinically by Harris Hip Score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analogue scale (VAS), 12-item Short Form Health Survey (SF- 12F/M) and radiographically (offset, CD angle, limb length discrepancy, cup inclination, subsidence, osseointegration, heterotopic ossification). Radiographic evaluations were carried out by 3 different blinded surgeons. A statistical analysis was performed (chi-square, t-test, Mann-Whitney). Results: At a mean follow-up of 30 months all the implanted stems were well-positioned and osseointegrated. In both groups there was a marked improvement in pain (p < 0.001) with a statistically significant advantage in the SS group for WOMAC (90.8 vs. 87.5; p = 0.02) and in part for HHS (93 vs. 91.7; p = 0.18). The radiographic evaluations, with high concordance correlation between the 3 blinded surgeons (ICC consistently >0.80), showed no significant differences in the restoration of the articular geometry, with a reduction of cortical hypertrophy (2% SS vs. 7% TS) and periprosthetic stress-shielding (p < 0.05) in the SS group. On the other hand, SS were more related to limb length discrepancy (61% vs. 33%; p < 0.05). No major complications were recorded in the 2 groups. Conclusion: Short stems were shown to be comparable or better than traditional implants at short-term follow-up. Keywords Mini-invasive THA, short stems, stemless hip prostheses, total hip arthroplasty Department of Orthopaedics, Università Cattolica del Sacro Cuore- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy Corresponding author: Giandomenico Logroscino, Policlinico Agostino Gemelli, Largo Francesco Vito,1 00168 Rome, Italy. Email: g.logroscino@gmail.com 813209HPI 0 0 10.1177/1120700018813209HIP InternationalLogroscino et al. research-article 2018 Original research article