[show abstract][hide abstract] ABSTRACT: This study was undertaken to determine incidence, associated risk factors, and clinical outcomes of a diastasis of pubic symphysis. Among 4,151 women, who delivered 4,554 babies at the Department of Obstetrics of Seoul National University Bundang hospital from January 2004 to December 2006, eleven women were diagnosed as having a symptomatic diastasis of pubic symphysis. We estimated the incidence of the diastasis and identified the associated risk factors. To evaluate the pain relief and reduction of diastasis we followed up the 11 diastatic patients. The incidence of the diastasis was 1/385. Primiparity (P = 0.010) and twin gestation (P = 0.016) appeared as risk factors for diastasis by univairable analysis; and twin gestation appeared to be the only risk factor (P = 0.006) by logistic analysis. Two patients were operated due to intractable pain; and the remaining nine patients were treated conservatively. The diastatic gap decreased to less than 1.5 cm by 2 to 6 weeks after the diagnosis and then remained stationary. At a mean follow-up of 22.1 months (range, 12 to 47 months), five of 11 patients had persistent symphysis pubis dysfunction. Diastasis is more frequent than generally acknowledged. Pregnant women with multiple gestations should be informed about the potential risk of pubic symphysis diastasis.
Journal of Korean medical science 02/2014; 29(2):281-6. · 0.84 Impact Factor
[show abstract][hide abstract] ABSTRACT: Patients with residual poliomyelitis can have advanced degenerative arthritis of the hip in the paralytic limb or the nonparalytic contralateral limb. Although THA is a treatment option for some of these patients, there are few studies regarding THA in this patient population.
We therefore reviewed a group of patients with residual poliomyelitis who underwent cementless THA on either their paralytic limb or nonparalytic limb to assess (1) Harris hip scores, (2) radiographic results, including implant loosening, (3) complications, including dislocation, and (4) limb length discrepancy after recovery from surgery.
From January 2000 to December 2009, 10 patients with residual poliomyelitis (10 hips, four paralytic limbs and six nonparalytic contralateral limbs) underwent THA using cementless prostheses. Harris hip scores, complications, and leg length discrepancy were determined by chart review, and confirmed by questionnaire and examination; radiographs were reviewed by two observers for this study. Followup was available for all 10 patients at a minimum of 3 years (median, 7 years; range, 3.4-13 years). Surgery was done at the same side of the paralytic limb in four hips and contralateral to the paralytic limb in six.
All patients had pain relief and improvement in function; the Harris hip score improved from mean of 68 preoperatively to 92 at last followup (p = 0.043). However, only three patients had complete pain relief. One hip dislocated, which was treated successfully with closed reduction and a hip spica cast for 2 months. There was no loosening or osteolysis in this series. Leg length discrepancy improved after the index operation, but only in the THAs performed in the paralytic limbs.
Cementless THA may be suitable for painful hips in adult patients with residual poliomyelitis. Nonetheless, these patients should be informed of the possibility of mild residual pain and persistent leg length discrepancy, particularly patients whose THA is performed on the limb that was not affected by polio (ie, the nonparalytic contralateral limb).
Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.
Clinical Orthopaedics and Related Research 11/2013; · 2.79 Impact Factor
[show abstract][hide abstract] ABSTRACT: Total hip arthroplasty (THA) for severe developmental dysplasia of the hip (DDH) is a technically demanding procedure for arthroplasty surgeons, and it is often difficult to reduce the hip joint without soft tissue release due to severe flexion contracture. We performed two-stage THAs in irreducible hips with expected lengthening of the affected limb after THA of over 2.5 cm or with flexion contractures of greater than 30 degrees in order to place the acetabular cup in the true acetabulum and to prevent neurologic deficits associated with acute elongation of the limb. The purpose of this study is to evaluate the outcomes of cementless THA in patients with severe DDH with a special focus on the results of two-stage THA.
Retrospective clinical and radiological evaluations were done on 17 patients with Crowe type III or IV developmental DDH treated by THA. There were 14 women and 3 men with a mean age of 52.3 years. Follow-ups averaged 52 months. Six cases were treated with two-stage THA followed by surgical hip liberalization and skeletal traction for 2 weeks.
The mean Harris hip score improved from 40.9 to 89.1, and mean leg length discrepancy (LLD) in 13 unilateral cases was reduced from 2.95 to 0.8 cm. In the patients who underwent two-stage surgery, no nerve palsy was observed, and the single one-stage patient with incomplete peroneal nerve palsy recovered fully 4 weeks postoperatively.
The short-term clinical and radiographic outcomes of primary cementless THA for patients with Crowe type III or IV DDH were encouraging. Two-stage THA followed by skeletal traction after soft tissue release could provide alternative solutions to the minimization of limb shortenings or LLD without neurologic deficits in highly selected patients.
Clinics in orthopedic surgery 09/2013; 5(3):167-73.
[show abstract][hide abstract] ABSTRACT: OBJECTIVES:: To evaluate the incidence of femoral neck fracture (FNF) after removal of a compression hip screw (CHS) without trauma and to determine the risk factors for this type of fracture. DESIGN:: Retrospective study of consecutive patient series SETTING:: University teaching hospital PATIENTS:: Sixty-seven patients with a mean age of 65.3 years (45 women and 22 men). INTERVENTION:: A total of 67 implants were removed in the presence of bony consolidation of the fracture site; most of them were due to hardware pain. MAIN OUTCOME MEASURES:: The incidence of FNF after a CHS removal, clinical parameters (age, gender, bone mineral density, body mass index, fracture stability), and radiological parameters (the femoral neck-shaft angle, femoral neck width, distance between thread of lag screw and neck cortex). Univariate analysis was performed for those parameters of the fracture group and the non-fracture group. To assess which variables were associated with FNF, a multiple logistic regression was used. RESULTS:: Six (9.0 %) FNFs occurred within 1 month after a CHS removal. The mean anterior and lateral neck widths were significantly smaller, and the mean anterior and inferior thread-to-cortex distances were significantly shorter in the fracture group compared with the non-fracture group. The risk factor significantly associated with FNF was the inferior thread-to-cortex distance (OR 0.462; 95% CI: 0.217; 0.988). CONCLUSIONS:: CHS should not be removed routinely due to the risk of FNF. Furthermore, attention should be paid to at risk patients with a hip screw positioned close to the inferior femoral neck cortex.
Journal of orthopaedic trauma 05/2013; · 1.78 Impact Factor
[show abstract][hide abstract] ABSTRACT: PURPOSE: In an alumina-on-alumina total hip arthroplasty (THA), recommended with a small inclination angle <45°, the acetabular component (cup) may be positioned more medially to be covered almost completely by host bone. The purpose of this study was to identify the correlating factors and to evaluate the outcomes of medial placement of the cup in patients with alumina-on-alumina THAs. METHODS: Using the propensity score matching with age, gender, body mass index, initial diagnosis, and the length of follow-up as variables, 38 hips with a medialized cup and 38 hips with a non-medialized one were identified from 389 hips in 347 who patients underwent primary alumina-on-alumina THA and followed up for more than 7 years. Clinical and radiological outcomes were compared between the two groups. RESULTS: Preoperative acetabular medial wall thickness and the cup inclination angle were significantly smaller in the medialization group compared to the non-medialization group. Center edge angle, cup size, and coverage by host bone were not significantly different between the two groups. The hip center of rotation was significantly medialized in the medialization group. The Harris hip scores were not significantly different between the two groups. No component loosening or osteolysis was observed and no revision was required in either groups. CONCLUSIONS: Thin acetabular medial wall and a small inclination angle of the cup were the correlating factors of medial placement of the cup in patients who underwent an alumina-on-alumina THA. Medial placement did not lead to differences in the clinical or radiological outcomes.
Archives of Orthopaedic and Trauma Surgery 12/2012; · 1.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: Umbilical cord blood (UCB) has recently been recognized as a new source of mesenchymal stem cells (MSCs) for use in stem cell therapy. We studied the effects of systemic injection of human UCB-MSCs and their conditioned medium (CM) on ovariectomy (OVX)-induced bone loss in nude mice. Ten-week-old female nude mice were divided into six groups: Sham-operated mice treated with vehicle (Sham-Vehicle), OVX mice subjected to UCB-MSCs (OVX-MSC) or human dermal fibroblasts (OVX-DFB) transplantation, OVX mice treated with UCB-MSCs CM (OVX-CM), zoledronate (OVX-Zol), or vehicle (OVX-Vehicle). Although OVX-Vehicle group exhibited significantly less bone mineral density (BMD) gain compared with Sham-Vehicle group, transplantation of hUCB-MSCs (OVX-MSC group) has effectively prevented OVX-induced bone mass attenuation. Notably, OVX-CM group also showed BMD preservation comparable to the OVX-MSC group. In addition, micro-CT analysis demonstrated improved trabecular parameters in both OVX-MSC and OVX-CM groups compared to OVX-Vehicle or OVX-DFB group. Histomorphometric analysis showed increased bone formation parameters, accompanied by increased serum procollagen type-I N-telopeptide levels in OVX-MSC and OVX-CM mice. However, cell trafficking analysis failed to demonstrate engraftment of MSCs in bone tissue 48 hrs after cell infusion. In vitro, hUCB-MSC CM increased alkaline phosphatase activity in human bone marrow-derived MSCs and mRNA expression of collagen type 1, Runx2, osterix, and alkaline phosphatase in C3H10T1/2 cells. Furthermore, hUCB-MSC CM significantly increased survival of osteocyte-like MLO-Y4 cells while it inhibited osteoclastic differentiation. To summarize, transplantation of hUCB-MSCs could effectively prevented OVX-mediated bone loss in nude mice which appears to be mediated by paracrine mechanism rather than direct engraftment of the MSCs.
Tissue Engineering Part A 12/2012; · 4.64 Impact Factor
[show abstract][hide abstract] ABSTRACT: OBJECTIVES:: We evaluated isolated fractures of the greater trochanter (IFGT) on plain radiographs with multiplanar reformation computed tomography (MPR CT). DESIGN:: Retrospective review of patients SETTING:: University teaching hospital PATIENTS:: This study included 27 consecutive patients with apparently isolated fractures of the greater trochanter MAIN OUTCOME MEASUREMENTS:: The clinical results, X-ray, CT, MRI, bone scintigraphy findings were investigated RESULTS:: Four of 27 cases demonstrated anterior cortical breakage or extensive damage of the trabecular bone in the intertrochanteric area on MPR CT images. Surgical fixation was necessary for these four cases. The other 23 cases, in which no structural damage was detected, were treated conservatively and the results were satisfactory without progression to a complete intertrochanteric fracture.All 9 cases evaluated with MR imaging demonstrated extension into the intertrochanteric area. In 5 cases, the extension crossed the midline on the mid-coronal image. Two of the cases were treated surgically because of anterior cortical breakage and extensive trabecular impaction on MPR CT, respectively. However, the other 3 cases and 4 cases with mild intertrochanteric extension were treated conservatively without problem. CONCLUSIONS:: The evaluation of IFGT with MPR CT was shown to be valuable for determining the optimal treatment method.
Journal of orthopaedic trauma 11/2012; · 1.78 Impact Factor
[show abstract][hide abstract] ABSTRACT: We evaluated the outcomes of 64 consecutive revision total hip arthroplasties with an alumina-on-alumina bearing surface in 61 patients with osteolysis. No implants had been rerevised nor was osteolysis detected at a mean of 9.8 years (range, 7.0-13.1 years) postoperatively. There was 1 case of stem loosening but no cup loosening or alumina bearing fractures. Two surgical procedures were performed for an infection in 1 patient. Three dislocations occurred in 3 hips; all were treated with closed reduction and abduction bracing for 3 months. No further dislocations occurred. With any reoperation or radiographic evidence of osteolysis or loosening as the end point, the 7-year survival rate was 96.9% (95% confidence interval, 90.8%-100%). The alumina-on-alumina bearing surfaces used for revision total hip arthroplasty in patients with osteolysis were found to produce encouraging clinical results and implant survival rates at a minimum of 7 years postoperatively.
The Journal of arthroplasty 11/2012; · 1.79 Impact Factor
[show abstract][hide abstract] ABSTRACT: The distal femur is a common site for benign or malignant bone tumors in children or adolescents. Distal femoral cortical irregularities at the posterior aspect of the distal femoral metaphysis must be differentiated from malignant bone tumors because they might be misinterpreted as malignant neoplasm. Plain radiographs of a 6-year-old girl complaining of left knee pain for 4 weeks showed cortical proliferation with excavation on her distal femoral metaphysis. Computed tomography, magnetic resonance imaging and bone scan helped to differentiate the cortical irregularity from malignant lesions. Therefore unnecessary invasive surgery was avoided in this patient.
European Journal of Orthopaedic Surgery & Traumatology 11/2012; · 0.18 Impact Factor
[show abstract][hide abstract] ABSTRACT: Wet processing of hydroxyapatite is useful in the preparation of a green body with a complex structure such as a porous body. For successful wet processing, a suspension with low viscosity and high solid loading is essential. The optimization of the suspension is typically achieved through the careful control of the parameters such as the amount of dispersant and the pH. The milling time was also presented as a significant parameter for the preparation of the suspension in this work. Excessive milling brought about an increase in viscosity, which subsequently resulted in a green body with reduced density. Due to the loose network of primary particles in the green body, the densification was not successfully achieved. The loose packing in the green body was attributed to the reduction of the absolute zeta potential with the increase in milling time.
Current Applied Physics 09/2012; 12:S71–S75. · 1.81 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND: THA in patients younger than 30 years presents challenges because of uncertainties regarding the long-term survivorship of prostheses. Alumina-on-alumina bearings, which exhibit little long-term wear, may be a reasonable option but the long-term survivorship is unknown. QUESTIONS/PURPOSES: We determined (1) the survival rate of alumina-on-alumina bearings in patients younger than 30 years after a 10-year followup, (2) the incidence of audible hip clicking and squeaking, (3) radiographic evidence of osteolysis, and (4) the effects on pregnancy, childbirth, and career choice. METHODS: We retrospectively reviewed 62 patients who had 75 THAs with alumina-on-alumina bearings followed more than 10 years (average, 11.5; range, 10-13.5 years). Mean patient age at the time of surgery was 24 years (range, 18-30 years). All operations were performed using the same cementless implant at a single center. We determined survival, presence of osteolysis, and function (Harris hip score, WOMAC). RESULTS: The 10-year survival rate of alumina-on-alumina bearings in THAs, with revision for any reason as the end point, was 98.9%. Audible hip clicking and squeaking were identified in 10 hips and two hips, respectively. No osteolysis was detected. None of the 11 patients who became pregnant had been affected by their THA during pregnancy or childbirth. Seven of the 14 patients who were unemployed at the time of index surgery stated that their THA affected their job choice. CONCLUSIONS: We found a high 10-year survival of cementless alumina-on-alumina bearings in THAs in patients younger than 30 years. Lifetime events such as job choice, pregnancy, and childbirth should be considered when choosing THA for patients younger than 30 years. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
Clinical Orthopaedics and Related Research 07/2012; · 2.79 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND: The acetabular cup should be properly oriented to prevent dislocation and to reduce wear. However, achieving proper cup placement is challenging with potentially large variations of cup position. We propose a new technique to position the acetabular cup. QUESTIONS/PURPOSES: We used this technique, then determined actual cup position and subsequent dislocation rate. METHODS: We measured acetabular abduction (α°) and anteversion (β°) on preoperative CT scans in 46 patients (50 hips) scheduled for THA. During the operation, we identified the transverse acetabular notch (TAN) and anterior acetabular notch (AAN), a notch at the anterior acetabular margin. We then marked two reference points for 40° abduction at the acetabular rim: the superior point, which is opposite the TAN, and the inferior point at |α - 40| mm inside (when α was > 40°) or outside the TAN (when α was < 40°). We also marked two reference points for 15° anteversion: the posterior point opposite the AAN and the anterior point at |β - 15| mm inside (when β was < 15°) or outside the AAN (when β was > 15°). During cup insertion, we aligned cup abduction to the line between the superior and inferior points and cup anteversion to the line between the anterior and posterior points. We measured cup abduction and anteversion and evaluated the dislocation rate. One patient was lost to followup before 60 months; the minimum followup for the other 45 patients was 60 months (mean, 62.8 months; range, 60-65 months). RESULTS: The mean cup abduction was 40° (range, 32°-47°) and the mean cup anteversion was 17° (range, 8°-25°). No dislocation occurred postoperatively in 49 hips (45 patients) for a minimum of 5 years followup. CONCLUSIONS: We obtained adequate cup position with our method and none of 45 patients (49 hips) had dislocation. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of level of evidence.
Clinical Orthopaedics and Related Research 07/2012; · 2.79 Impact Factor
[show abstract][hide abstract] ABSTRACT: We evaluated the clinical and radiologic results of impacted femoral neck fractures treated with multiple pinning and determined the influence of the progression of impaction at the fracture site on clinical outcome.
There were 34 patients with a mean age of 65.5 years. The mean follow-up period was 3.4 years. Progression of fracture site impaction was measured using an articulo-trochanteric distance index and the percentage decrease in the articulo-trochanteric distance index between follow-up intervals. The failure of treatment was clarified as non-union and avascular necrosis. Other characteristics of the patients, including mean waiting time for surgery, preoperative Singh index score, and body mass index, were also measured to evaluate the influence on the clinical outcome of surgery.
There were 6 fractures which were not treated successfully (3 non-union, 8.8% and 3 avascular necrosis, 8.8%). The mean percentage decrease of the articulo-trochanteric distance index within the first 6 weeks after surgery was 4.5% in the successful group and 25.1% in the failure group (p < 0.001). There was also a significant mean percentage decrease in the articulo-trochanteric distance index between 6 weeks and 3 months (p < 0.001).
Primary stabilization with Knowles pins for impacted femoral neck fractures had a reasonable clinical outcome with low morbidity. Despite a significant difference of a mean percentage decrease in the articulo-trochanteric distance index between the successful group and the failure group, we could not verify it as a risk factor for failure of treatment because the odds ratio was not statistically significant.
Clinics in orthopedic surgery 03/2012; 4(1):66-71.
[show abstract][hide abstract] ABSTRACT: The principal objective of this study was to evaluate the effects of surface pretreatment with platelet-rich plasma (PRP) on the cellular functions of human bone marrow stromal cells (hBMSCs). The surfaces of tissue culture plates (TCPs) were pretreated by adding PRP followed by centrifugation to bring platelets closer to the surface, followed by incubation for 60 min at 37°C. Then, hBMSCs were seeded onto TCP and TCP pretreated with PRP (TCP-PRP), followed by culture in osteogenic medium. Cell attachment, proliferation, and osteogenic differentiation were evaluated. Field emission scanning electron microscope (FE-SEM; JSM-7401F, JEOL Ltd., Japan) observations were conducted. The attachment of hBMSCs was significantly lower on TCP-PRP than on TCP. However, when the cell numbers were normalized with those observed on day 1 of culture, cellular proliferation on 5 days was significantly higher on TCP-PRP. Alkaline phosphatase activity, an index of early phase of osteoblastic differentiation, was significantly higher on TCP-PRP on day 14. Calcium deposition amount, an index of terminal osteoblastic differentiation, was also significantly higher on TCP-PRP on days 14 and 21. The results of von Kossa staining confirmed that, on day 21, the area of mineralized nodules was significantly larger on TCP-PRP. FE-SEM observation demonstrated that activated platelets and fibrin network covered the surface after PRP treatment. An increase in the number of hBMSCs and their cellular products was evident on the FE-SEM observation, and the fibrin network remained on day 21. Our results demonstrate that a PRP-treated surface enhanced early proliferation and late osteogenic differentiation of hBMSCs.
Connective tissue research 02/2012; 53(4):318-26. · 1.55 Impact Factor
[show abstract][hide abstract] ABSTRACT: There are growing demands for bioactive titanium implants that could shorten the healing period, promote faster rehabilitation, and thereby increase the success rate of treating patients with poor bone quality. A synthetic receptor-binding peptide mimicking bone morphogenetic protein-2 (BMP-2) was covalently linked to a titanium alloy with two types of topography-machined (TiMA) and rough (TiGB)-by using a chemical conjugation process. In vivo osseointegration capacity was evaluated chronologically using histomorphometric analysis at 2, 4, and 8 weeks after implantation in the distal femurs of rabbits. In the histologic examinations, peri-implant bone formation was more active around TiGB than TiMA. Compared to the control groups (nonconjugated TiMA and TiGB) at 2, 4, and 8 weeks, the peptide-conjugated groups (TiMA-P and TiGB-P) had more mature new bone, thicker trabeculae, more rapid bone maturation, and higher affinity index (percentage of new bone contact length) in histomorphometric analysis. Particularly, differences in the affinity index between the peptide-conjugated and nonconjugated groups were more pronounced at the early phase of peri-implant healing (2 and 4 weeks). However, at 8 weeks, enhanced bone formation was less prominent according to peptide conjugation, especially in specimens with a rough surface. The titanium alloys in the rabbit femurs led to a significant increase of bone growth when modified with bioactive peptides, especially during the early phase of bone healing. These results confirm that biochemical modifications of titanium surfaces can enhance the rate of bone healing compared with that of untreated titanium surfaces.
Connective tissue research 02/2012; 53(5):359-65. · 1.55 Impact Factor
[show abstract][hide abstract] ABSTRACT: Abstract The principal objective of this study was to evaluate the effects of surface pre-treatment with platelet-rich plasma (PRP) on the cellular functions of human bone marrow stromal cells (hBMSCs). The surfaces of tissue culture plates (TCPs) were pre-treated by adding PRP followed by centrifugation to bring platelets closer to the surface, followed by incubation for 60 min at 37°C. Then, hBMSCs were seeded onto TCP and TCP pre-treated with PRP (TCP-PRP), followed by culture in osteogenic medium. Cell attachment, proliferation, and osteogenic differentiation were evaluated. Field emission scanning electron microscope (FE-SEM) observations were conducted. The attachment of hBMSCs was significantly lower on TCP-PRP than on TCP. However, when the cell numbers were normalized with those observed on day 1 of culture, cellular proliferation on 5 days was significantly higher on TCP-PRP. ALP activity, an index of early phase of osteoblastic differentiation, was significantly higher on TCP-PRP on day 14. Calcium deposition amount, an index of terminal osteoblastic differentiation, was also significantly higher on TCP-PRP on days 14 and 21. The results of von Kossa staining confirmed that, on day 21, the area of mineralized nodules was significantly larger on TCP-PRP. FE-SEM observation demonstrated that activated platelets and fibrin network covered the surface after PRP treatment. An increase in the number of hBMSCs and their cellular products was evident on the FE-SEM observation, and the fibrin network remained on day 21. Our results demonstrate that a PRP-treated surface enhanced early proliferation and late osteogenic differentiation of hBMSCs.
Connective tissue research 01/2012; · 1.55 Impact Factor
[show abstract][hide abstract] ABSTRACT: Subchondral stress fractures of the femoral head may be either of the insufficiency-type with poor quality bone or the fatigue-type with normal quality bone but subject to high repetitive stresses. Unlike osteonecrosis, multiple site involvement rarely has been reported for subchondral stress fractures. We describe a case of multifocal subchondral stress fractures involving femoral heads and medial tibial condyles bilaterally within 2 weeks.
A 27-year-old military recruit began having left knee pain after 2 weeks of basic training, without any injury. Subsequently, right knee, right hip, and left hip pain developed sequentially within 2 weeks. The diagnosis of multifocal subchondral stress fracture was confirmed by plain radiographs and MR images. Nonoperative treatment of the subchondral stress fractures of both medial tibial condyles and the left uncollapsed femoral head resulted in resolution of symptoms. The collapsed right femoral head was treated with a fibular strut allograft to restore congruity and healed without further collapse.
There has been one case report in which an insufficiency-type subchondral stress fracture of the femoral head and medial femoral condyle occurred within a 2-year interval.
Because the incidence of bilateral subchondral stress fractures of the femoral head is low and multifocal involvement has not been reported, multifocal subchondral stress fractures can be confused with multifocal osteonecrosis. Our case shows that subchondral stress fractures can occur in multiple sites almost simultaneously.
Clinical Orthopaedics and Related Research 12/2011; 470(3):944-9. · 2.79 Impact Factor
[show abstract][hide abstract] ABSTRACT: We describe the case of a healthy young man with a femoral head fracture by low-energy trauma that occurred without evidence of hip dislocation. While plain radiographs showed no definite fracture or dislocation, computed tomography (CT) and magnetic resonance imaging (MRI) revealed a femoral head fracture with a wedge-shaped cortical depression at the superomedial aspect of the femoral head. Our patient reported feeling that the right hip had been displaced from its joint for a moment. This probably represented subluxation with spontaneous relocation. The characteristic findings and possible mechanisms of this fracture were postulated on the basis of the sequential 3 dimensional-CT and MRI. The clinical results of conservative treatment were better than those of previously reported indentation fractures.
Clinics in orthopedic surgery 12/2011; 3(4):336-41.
[show abstract][hide abstract] ABSTRACT: Although the incidence of malignant tumors in patients undergoing total hip arthroplasties (THAs) is known to be lower than the general population, there exist several reports on the development of malignant tumors at the site of THAs. We report another case of malignant fibrous histiocytoma at the site of a THA, which was developed in an older patient who presented a cystic mass around the total hip prosthesis using a ceramic-on-ceramic bearing system, even without evidence of osteolysis or loosening of implants. This is the second case associated with an aluminum oxide prosthesis in English literature.
The Journal of arthroplasty 03/2011; 27(2):324.e9-324.e12. · 1.79 Impact Factor
[show abstract][hide abstract] ABSTRACT: Although impingement between the neck of the metallic stem and the ceramic liner has been suspected to be the cause of ceramic liner failure in ceramic-on-ceramic total hip arthroplasty (THA), no report has directly demonstrated microscopic damage on ceramic liner. We performed 18 reoperations on 18 patients who had undergone third generation ceramic-on-ceramic THA. Considering impingement, 16 patients, who were reoperated more than 1 year after previous ceramic bearing THA, were evaluated. Retrieved alumina liners, showing evidence of impingement, were examined by means of visual inspection and scanning electron microscopy (SEM). Four of the 16 hips showed neck notching and black stained liners, evidence of metallic neck to ceramic impingement. Impinged alumina bearings had been implanted for an average of 62.5 months (range: 35-99 months) before reoperation. SEM of the black stained area demonstrated disruptive wear and loss of surface integrity. Furthermore, one liner had multiple microcracks, and its cross-sectional SEM analysis revealed one microcrack propagating into the deep portion of the ceramic liner. Our observations suggest that metal neck-to-ceramic impingement in ceramic-on-ceramic THA can cause microcrack formation in ceramic liner.
Journal of Orthopaedic Research 02/2011; 29(2):218-22. · 2.88 Impact Factor