Total Hip Arthroplasty Using S-ROM Prosthesis for Dysplastic Hip scan. According to these authors, the bone loss on the proxi- mal side was significantly decreased by using an S-ROM as opposed to an anatomic medullary locking stem (DePuy Orthopaedics, Warsaw, IN, USA). Particularly, regarding bone loss in the cortex on the distal area of the lesser trochan- ter and the medial side of the femoral head, the S-ROM showed a lesser extent of bone loss than that of the AML. In the current study, a decreased shadow of the calcar femo- rale was observed in 16 cases (35.5%) at the final follow-up. However, no progressive bone loss of the proximal femur due to stress shielding was observed in our series. The possibility of developing osteolysis due to dissociat- ed metal particles is one of the concerns when using a mod- ular stem. Tanzer, et al.22 reported that osteolysis occurred in 42% of the patients who underwent total hip arthroplasty using the S-ROM modular stem. Cook, et al.23 reported that great care must be taken when using a modular stem be- cause metal particles are formed and can cause osteolysis, leading to loosening of the prosthesis and pain, in cases in which fatigue loading was exerted on a repeated basis. Oth- er studies24,25 have also reported that the metal particles pro- duced by the movement of the modular stems could lead to third body wear of the bearing surface. Krygier, et al.26 re- ported that the modular connecting area was stable despite the dissociation of metal particles. These authors also noted that it remains unclear as to whether metal particles pro- duce third-body erosion or if this is due to an immunologic reaction. Chandler, et al.27 reported that there was no ero- sion between the sleeve and stem during revision surgery us- ing S-ROM. According to a review of the literature, Spitzer15 also reported that there were no areas showing erosion in the connecting site of the modular stems. The stability of the S-ROM has been demonstrated in prior reports. Al- though our current study conducted mid to long-term fol- low-up observation, all the stems were stable and no osteol- ysis of the distal femur was observed. We believe these results are related to the design of this prosthesis. The de- sign of this stem offers maximal proximal and distal filling with modularity and rotational stability. Use of the S-ROM stem is recommended for performing arthroplasty in pa- tients with coxarthrosis and a dysplastic hip. ACKNOWLEDGEMENTS This work was supported by a research grant from Inha University. REFERENCES 1. Aronson J. Osteoarthritis of the young adult hip: etiology and treatment. Instr Course Lect 1986;35:119-28. 2. Cameron HU. Management of femoral deformities during the to- tal hip replacement. Orthopedics 1996;19:745-6. 3. Gill TJ, Sledge JB, Müller ME. 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Cameron HU, Botsford DJ, Park YS. Influence of the Crowe rat- ing on the outcome of total hip arthroplasty in congenital hip dys- Yonsei Med J http://www.eymj.org Volume 52 Number 4 July 2011 659