Kyu-Tae Hwang

Cementless Total Hip Arthroplasty With a Metal-on-Metal Bearing in Patients Younger Than 50 Years

Total hip arthroplasty (THA) longevity is the primary concern in young patients. Metal-on-metal articulations were reintroduced to reduce polyethylene particle-induced osteolysis and improve survivorship; to date, based on issued reports, this strategy appears to have been successful. In this study, the authors investigated metal-on-metal articulation survivorship and osteolysis incidence in young patients (19-50 years old at index operations) and retrospectively reviewed cementless metal-on-metal THAs in 70 patients (78 hips) with a mean follow-up of 12.4 years. Metasul articulation was used with the Wagner acetabular component in all. Survivorship with revision for any cause was 98.7% (95% confidence interval, 98%-100%), and survivorship due to the development of osteolysis for any lesion was 97.5% (95% confidence interval, 95%-99%). Mean Harris hip score improved from 51 to 95 points at final follow-up. The findings of this study indicate that outcomes of cementless THA with a metal-on-metal bearing in young patients are satisfactory. However, longer-term studies in larger cohorts are required to determine whether metal-on-metal articulations are really a favorable option in young patients.

Total hip arthroplasty using cementless grit-blasted femoral component: a minimum 10-year follow-up study.

The grit-blasted cementless Spotorno (CLS) stem, which has excellent survival rates up to 10 years, is widely used in total hip arthroplasty (THA). We investigated the survivorships of CLS stems in THA at a minimum follow-up of 10 years and sought to identify factors that influence outcomes. A total of 227 hips of 191 patients who underwent cementless THA with a CLS stem were retrospectively reviewed at a mean follow-up of 12.3 years. All patients were evaluated clinically and radiographically according to implant type and surgery-related and patient-related factors. Survivorship was 97.2% when femoral revision for any reason was defined as the end point. Femoral revisions were performed in 3 hips because of periprosthetic fractures. Survivorship for all hips, using revision for any reason as the end point, was 92.6%. Two metal-on-metal THAs were revised because of aseptic loosening or osteolysis around the cup. No significant differences were evident for type of stem, type of bearing surface, stem alignment, or patient-related factors. However, a canal fill index of 80% or less was found to affect cortical remodeling, subsidence, and a change in stem position of 5° or more, which indicates that care must be taken not to undersize stems. In addition, in view of the revisions performed, bearing surfaces appear to importantly influence THA survivorship.

Is second generation metal-on-metal primary total hip arthroplasty with a 28 mm head a worthy option?: a 12- to 18-year follow-up study.

To determine whether MoM THA with a small head is still worthy of use, we investigated survivorship, complications, and factors influencing failure. Of 149 consecutive patients (195 hips), 141 (180 hips) of mean age 43 (19-55) years were available for review at a mean of 14.4 years postoperatively. Survivorship for cup revision for any cause was 97.8% at 18.4 years postoperatively. Nine hips generated complaints of groin pain; six showed periacetabular osteolysis, one had pain without radiological change, and two were diagnosed as symptomatic pseudotumors. Four of six hips with periacetabular osteolysis or aseptic loosening were revised. Surgery- and patient-related factors had no effect in results. Our results are encouraging, however, further study will be necessary to determine the incidence and fates of pseudotumors after MoM THA with a small head.

Isolated acetabular revision hip arthroplasty with the use of uncemented cup.

We evaluated the clinical and radiological results of isolated acetabular revision hip arthroplasty. Forty-three hips underwent isolated acetabular revision with uncemented cup and were followed up for an average of 76 months. The monoblock femoral stems were used in 20 hips and modular femoral stems in 23 hips. The average Harris Hip Score improved to 87 at last follow-up from 57 preoperatively. All femoral stems maintained stable fixation with bone ingrowth and no subsidence at last follow-up. Five hips with the monoblock stem underwent rerevision due to loosening of cup with osteolysis. The isolated acetabular revision is encouraging, but in reflection of the results of the monoblock head, the visual inspection of the femoral head is not enough for evaluation of its surface status.

Isolated Acetabular Revision With Ceramic-on-Ceramic Bearings Using a Ceramic Head With a Metal Sleeve

The purpose of this study is to evaluate results of isolated acetabular revision with ceramic-on-ceramic bearings using a ceramic head with a metal sleeve. A retrospective review of fifty-three hips was performed. The mean patient age was 49.9years and the mean follow-up period was 5.7years. The mean modified Harris hip score improved from 47.5, pre-operatively, to 84.7 at the time of last follow-up (P<0.001). Two patients reported squeaking of the hip. Three patients experienced loosening cup, necessitating re-revision surgery. There was a significant difference of acetabular bone defect between loose cup group and stable cup group (P=0.018). There were no ceramic fractures and no osteolysis. The survival rate of the acetabular cup at the mid-term follow-up was 94.3%. In conclusion, ceramic head with a metal sleeve can be a reliable option for isolated acetabular revision.

Cementless bipolar hemiarthroplasty for unstable intertrochanteric fractures in octogenarians

OBJECTIVE The aim of this study was to evaluate the clinical and radiographic outcomes of bipolar hemiarthroplasty with cementless stem for the unstable intertrochanteric fracture in octogenarians and to determine the influencing factors associated with subsidence of the stem. METHODS The study included the 143 hips of 139 patients (119 females, 20 males). Mean follow-up period was 3.8 (range: 2.2 to 9.0) years. The displaced lesser trochanteric fragment was reduced anatomically and fixed with 16-gauge stainless steel cerclage wire. Clinical outcomes included Harris Hip Score (HHS), thigh pain, groin pain and walking ability. Radiographic outcomes included stem fixation and stability, osteolysis, heterotopic ossification and subsidence. The stable reduction group was determined when anatomic reduction of posteromedial fragments was achieved with ≤1 mm gap of fragment. RESULTS Mean HHS was 82 (range: 78 to 99) at the final follow-up. Thirty-one hips (21.7%) experienced thigh pain and 19 (13.3%) groin pain. One hundred and twelve patients (80.6%) regained their pre-injury level of ambulation. All femoral stems showed osseointegration without aseptic loosening and osteolysis. The mean stem subsidence was 3.1±2.4 (range: 0 to 18) mm. The extent of subsidence was significantly higher in patients with unstable reduction. The survival rate was 94.2%. CONCLUSION Cementless bipolar hemiarthroplasty appears to be a suitable method for the treatment of intertrochanteric fracture in octogenarians. However, stable fixation of the posteromedial fragment is necessary to avoid stem subsidence.

Risk Factors Associated with Dislocation after Bipolar Hemiarthroplasty in Elderly Patients with Femoral Neck Fracture

Purpose We investigated the incidence and time of dislocation and other factors associated with dislocation of bipolar hemiarthroplasty related to the treatment of femoral neck fracture in old age patients. Materials and Methods Between January 2002 and April 2014, 498 femoral neck fractures (467 patients) were treated with bipolar hemiarthroplasty and included in this study. All surgeries were performed using the postero-lateral approach. The incidence of dislocation was investigated. A comparative analysis between a control group and dislocation group was performed with respect to patient factors including age, gender, body mass index, comorbidities, the ASA (American Society of Anesthesiologists) score, mental status and center-edge angle, and surgical factors including type of femoral stem, leg length discrepancy, femoral offset and method of short external rotator (SER) reconstruction. Results The incidence of dislocation was 3.8%, and the dislocation occurred on average 2.2 months (range, 0.6-6.5 months) after operation. No difference in patient-related factors was observed between the two groups. However, a smaller center edge (CE) angle was observed in the dislocation group (42.1°±3.2° vs. 46.9°±5.4°, P<0.001), and significantly lower incidence of dislocation was observed in tendon to bone repair group (0.7% vs 7.8%, P<0.001). Conclusion SERs should be repaired using the tendon-to-bone repair method to reduce dislocation rate in elderly patients who undergo bipolar hemiarthroplasty using the postero-lateral approach due to femoral neck fracture. In addition, patients with smaller CE angle should be carefully monitored due to high incidence of dislocation.

Identification and characterization of human bone-derived cells

This study was designed to identify and characterize primary bone-derived cells (BdCs) and investigate the potential role of osteoblast differentiation. Primary BdCs were isolated from surgical bone for comparative analysis with mesenchymal stem cells (MSCs) and fetal osteoblasts (FOBs) and for potential differentiation to mature osteoblasts. Using three different cells, we successfully cultivated human osteoblast differentiation and activity which were evaluated using microarray and biochemical methods. BdCs are more correlated to MSCs in bioinformatics result and similar with FOBs in gene expression. In particular, Osterix, osteoprogenitor marker, was high expressed in BdCs, while the expression in MSCs and FOBs were very low. Furthermore, BdCs exhibited a marked alkaline phosphatase (ALP) expression, early stage of osteogenic marker, and retained osteogenic properties and physiological changes into maturation as in FOBs. BdCs also showed an increase in bone morphogenic protein 2 (BMP2), osteopontin (OPN), and osteocalcin (OCN) mRNA expressions during differentiation. This study suggests that BdCs may be osteoprogenitor cells or undifferentiated preosteoblasts with strong capacity to differentiate toward mature osteoblasts.

Long-Term Outcomes After Metal-on-Metal Total Hip Arthroplasty With a 28-mm Head: A 17- to 23-Year Follow-Up Study of a Previous Report

BACKGROUND Second-generation, metal-on-metal total hip arthroplasty (MoM THA) using a 28-mm head has shown favorable results compared with large head MoM THA. The purpose of this study is to evaluate the long-term outcomes of cementless primary MoM THA with a 28-mm head and the incidence of osteolysis using computed tomography. METHODS A total of 92 patients (53 men and 39 women) who underwent primary cementless MoM THA (114 hips) with a 28-mm head were enrolled in this study. Their mean age was 46.2 years at the time of surgery. The mean follow-up duration was 20 years. The Harris hip score, presence of thigh or groin pain, radiographic results, presence of peri-implant osteolysis, histologic analysis, and Kaplan-Meier survival curves were evaluated. RESULTS The mean preoperative Harris hip score of 50.5 improved to 85.1 at the final follow-up. Eight patients (8 hips) experienced groin pain, but none had thigh pain. Twelve revisions (6.2%) were performed including 10 hips for aseptic loosening with osteolysis and 2 hips for periprosthetic fracture around the stem. At 23 years, 91% of patients were free from revision of the acetabular component due to aseptic loosening and 90.1% were free from revision of both femoral and acetabular components due to any reason. Osteolysis was identified around the cup in 12 cases (10.5%) and around the stem in 7 cases (6.1%). CONCLUSION MoM THA with a 28-mm head showed a relatively low rate of aseptic implant loosening at a mean follow-up of 20 years.

A higher association of medial collateral ligament injury of the knee in pronation injuries of the ankle

IntroductionTo evaluate the prevalence of medial collateral ligament (MCL) injury of the knee among ankle-fracture patients and to determine the risk factors associated with MCL injury in this patient group.Materials and methods303 patients (303 affected ankles) who underwent surgical treatment for an ankle fracture were assessed. Supination versus pronation injury, Danis-Weber classification, age, sex, body mass index (BMI), limb dominance, and mechanism of injury were reviewed to identify factors related to MCL injury.ResultsPrevalence of MCL injury of the knee among the total number of patients with an ankle fracture was 3.96% (12 out of 303 injuries). Multivariable logistic and linear regression analysis with adjustment of possible confounding factors confirmed that female sex and pronation injury were associated significantly (p < 0.05) with MCL injury.ConclusionsThe prevalence of MCL injury among females and the pronation type of ankle injury was 8.19% (10 out of 122 females) and 10.75% (10 out of 93 pronation injuries), respectively. More careful physical examination of the knee joint is strongly recommended in patients with ankle fractures, especially if the patient is female or the ankle-fracture pattern corresponds to the pronation type of injury.