Wedge femoral stems used in total hip arthroplasty (THA) have evolved with modifications including shorter lengths, reduced distal geometries, and modular necks. Unlike fit and fill stems which contact most of the metaphysis, tapered wedge femoral stems are designed to achieve proximal medial/lateral fixation. These single taper, wedge stems have demonstrated positive clinical outcomes. The tapered wedge stem evaluated in this study has further reduced distal geometry to provide a wedge-fit within the metaphysis of the proximal femoral canal for all femur types (Dorr A, B, C). The objective of this study was to evaluate the early clinical outcomes, including femoral stem subsidence, of a tapered wedge femoral stem. Fifty subjects (28 males, 22 females; mean age: 64.7±9.7 years; mean BMI: 29.6±4.6) underwent primary THA with a tapered wedge femoral stem. IRB approval was received prior to conducting the study and all participants signed the informed consent. Clinical data outcomes for this study included the Harris Hip Score (HHS), the Oxford Hip Score (OHS), revisions, and subsidence at the 6-week, 3-month, 1-year, and 2-year post-operative time points. Femoral stem subsidence was measured by an independent third party. Student t-tests were used to identify significant mean differences between genders (p<0.05).INTRODUCTION
METHODS
Additive manufacturing (3D printing) is used to create porous surfaces that promote bone ingrowth in an effort to improve initial stability and optimize long-term biological fixation. The acetabular cup that was studied is manufactured with titanium alloy powder via electron beam melting. Electron beam melting integrates the porous and solid substrate rather than sintering a porous coating to a solid surface. The 3D-printed acetabular cup's high surface coefficient of friction (up to 1.2), combined with its geometry, creates a predictable press-fit in the acetabulum, improving initial mechanical stability and ultimately leading to reproducible biologic fixation. The objective of this study was to evaluate the early clinical outcomes and implant fixation of this 3D-printed acetabular cup in total hip arthroplasty (THA). Four hundred twenty-eight subjects from 8 US and international research sites underwent primary THA with the 3D-printed acetabular cup. All sites received IRB approval prior to conducting the study, and all participants signed the informed consent. Screw usage and number used during surgery were used as a surrogate measurement for initial implant fixation. Clinical performance outcomes included pre- and post-operative Harris Hip Scores (HHS) and Oxford Hip Scores (OHS), patient satisfaction, and revision assessment. 215 patients had a minimum 1-year post-operative follow-up visit. Student t-tests were used to identify significant mean differences (p<0.05).INTRODUCTION
METHODS
Short femoral stem use in total hip arthroplasty (THA) has increased due to positive short-term clinical and biomechanical success. A neck preserving femoral stem not only preserves proximal bone volume, but preserves the high quality bone of the medial neck. The short stem design allows for less invasive surgical exposure and less invasive violation of the femoral canal (Figure 1). Additionally, it facilitates future revision THA, if needed, with a conventional primary stem. The objective of this study was to evaluate the early clinical outcomes of the Alteon® Neck Preserving Femoral Stem (Exactech, Inc.). Forty-nine subjects (25 males, 24 females; mean age: 58.3±7.6 years; mean BMI: 29.8±5.6) from 2 sites underwent primary THA with the Alteon Neck Preserving Femoral Stem. All participants signed the informed consent, and both sites received IRB approval prior to conducting the study. Clinical data outcomes for this study included the Harris Hip Score (HHS), the Oxford Hip Score (OHS), revisions, and subsidence at 3-month, 1-year, and 2-year post-operative time points. Subsidence was measured by an independent third party. Student t-tests were used to identify significant mean differences between genders (p<0.05).INTRODUCTION
METHODS
First generation uncemented modular cups reproduciblyfixed to bone but they were associated with unacceptable rates of pelvicosteolysis and mechanical failure. Consequently, second generation cups weredeveloped with shells having a limited number of holes or no holes, and improved conformity and locking mechanisms with the liner. The purpose of this study is to report the clinical and radiographic results of a second generation acetabular component for primary total hip arthroplasty. 297 patients who underwent 335 consecutive primary total hip arthroplasties by a single surgeon with the Trilogy modular acetabular component were followed clinically with the Hospital for Special Surgery Hip Scoring System and radiographs, for 4 to 7 years. All cups were implanted with a press-fit technique. This second generation acetabular cup design achieved predictable fixation and was associated with a low prevalence of revision for loosening and low prevalence of osteolysis at an intermediate follow up.
The role of surface finish on the survivorship of cemented stems is controversial. The purpose of this study is to prospectively evaluate the mid-term clinical and radiographic performance of a cohort of patients who underwent total hip replacement with two identical cemented femoral stems differing only in surface finish (VerSys, Zimmer, Warsaw, IN). 64 total hip replacements with a rough stem (Ra: 70–100 micro inches) and 138 total hip replacements with a satin finish stem (Ra: 20–25 micro inches) were followed clinically and radio graphically for 4 to 7 years. All surgeries were performed by one surgeon, during a period of 1 year, utilizing the same surgical approach and technique, ace tabular cup, cement type and cementing technique. The groups had similar demographics, diagnosis, preoperative clinical score, cement mantle quality, alignment, and length of follow up. The preoperative and postoperative Hospital for Special Surgery Hip Score at last follow up of the patients with a successful operation was not significantly different among the two groups. Five hips in the rough group and none in the satin group developed aseptic loosening and required revision (p=0.0009). The femoral bone-cement interface revealed progressive radiolucent lines or osteolysis in 8 out of 64 rough stems and in 3 out of 138 satin stems (p=0.01). There were progressive radiolucenciesor osteolysis in 44 out of possible 448 Gruen zones in the rough surface group and in 8 out of possible 966 Gruen zones in the satin finish group(p<
0.001). A rough, textured stem is more likely to fail at intermediate follow-up than a satin surface stem. We recommend that the surface of cemented stems should be satin or polished, with a Ra of less than 20 micro inches.
The role of surface finish on the survivorship of cemented stems is controversial. The purpose of this study is to prospectively evaluate the mid-term clinical and radiographic performance of a cohort of patients who underwent total hip replacement with two identical cemented femoral stems differing only in surface finish (VerSys, Zimmer, Warsaw, IN). 64 total hip replacements with a rough stem (Ra: 70–100 microinches) and 138 total hip replacements with a satin finish stem (Ra: 20–25 microinches) were followed clinically and radiographically for 4 to 7 years. All surgeries were performed by one surgeon during a period of 1 year, utilizing the same surgical technique, acetabular cup, cement type and cementing technique. The groups had similar demographics, diagnosis, preoperative clinical score, cement mantle quality, alignment, and length of follow up. The preoperative and postoperative Hospital for Special Surgery Hip Score at last follow up of the patients with a successful operation was not significantly different among the two groups. Five hips in the rough group and none in the satin group developed aseptic loosening (p=0.0009). The femoral bone-cement interface revealed progressive radiolucent lines or osteolysis in 8 out of 64 rough stems and in 3 out of 138 satin stems (p=0.01). There were progressive radiolucencies or oste-olysis in 44 out of possible 448 Gruen zones in the rough surface group and in 8 out of possible 966 Gruen zones in the satin finish group (p<
0.001). A rough, textured stem is more likely to fail at intermediate follow-up than a satin surface stem. We recommend that the surface of cemented stems should be satin or polished, with a Ra of less than 20 microinches.
