Culture-Expanded Autologous AdiposeDerived Mesenchymal Stem Cell Treatment for Osteonecrosis of the Femoral Head

Background@#Outcomes of traditional treatment for osteonecrosis of the femoral head (ONFH) are not always satisfactory. Hence, cell-supplementation therapy has been attempted to facilitate necrotic-tissue regeneration. Adipose-derived mesenchymal stem cell (ADMSC) transplantation is potentially advantageous over bone marrow-derived MSC implantation, but its outcomes for ONFH remain unclear. The aim of this study was to determine 2-year radiological and clinical outcomes of culture-expanded autologous ADMSC implantation for ONFH. @*Methods@#Eighteen hips with necrotic lesions involving ≥ 30% of the femoral head were included. ADMSCs were harvested by liposuction and culture expanded for 3 passages over 3 weeks. With a 6-mm single drilling, ADMSCs were implanted into the necrotic zone. All patients underwent magnetic resonance imaging (MRI), single-photon emission computed tomography/computed tomography (SPECT/CT) at screening and 6 months, 12 months, and 24 months postoperatively. The primary outcome was the change in the size of necrotic area on MRI. Secondary outcomes were changes in clinical scores and radioisotope uptake on SPECT/CT. Conversion total hip arthroplasty (THA) was defined as the endpoint. @*Results@#Preoperatively, the necrotic lesion extent was 63.0% (38.4%–96.7%) of the femoral head. The mean Harris hip score was 89.2, the University of California at Los Angeles (UCLA) score was 5.6, and Western Ontario and McMaster Universities Arthritis index (WOMAC) was 79.4. Three patients underwent THA and 1 patient died in an accident. Finally, 11 patients (14 hips) were available for ≥ 2-year follow-up. At the last follow-up, no surgery-related complications occurred, and 14 of 17 hips (82%) were able to perform daily activities without THA requirement. There was no significant decrease in lesion size between any 2 intervals on MRI.However, widening of high signal intensity bands on T2-weighted images inside the necrotic lesion was observed in 9 of 14 hips (64%); 11 of 14 hips (79%) showed increased vascularity on SPECT/CT at 2 years postoperatively. No significant differences were observed between preoperative and 24-month mean Harris hip score (89.2 vs. 88.6), WOMAC (79.4 vs. 75.7), and UCLA score (5.6 vs. 6.2). @*Conclusions@#Our outcomes suggest that culture-expanded ADMSC implantation is a viable option for ONFH treatment without adverse events.

Characterization of Tendon-Specific Markers in Various Human Tissues, Tenocytes and Mesenchymal Stem Cells

BACKGROUND: Unlike bone, cartilage, or muscle, tendon-specific markers are not well established. The purpose of the study was to investigate expression pattern and level of 6 well-known tendon-specific markers, in various human musculoskeletal tissues, tenocytes, and mesenchymal stem cells (MSCs). METHODS: Musculoskeletal tissue samples of tendon, bone, cartilage, nerve, muscle, and fat were obtained from patients undergoing orthopedic surgery. Tenocytes, MSCs from bone marrow, adipose tissue, and umbilical cord were isolated from each tissue and cultured. Six tendon-specific markers, scleraxis (Scx), tenomodulin (TNMD), thrombospondin-4 (TSP-4), tenascin-C (TNC), type I collagen (Col I), and type III collagen (Col III) were investigated in tendon tissue, tenocytes, and MSCs. RESULTS: mRNA levels of 6 tendon-specific markers were significantly higher in tendon tissue that in other connective tissues levels of Scx, TNMD, TSP-4, and Col III immediately decreased after plating tenocytes in culture dishes whereas those of TNC and Col I did not. In comparison with tendon tissue, mRNA levels pattern of Scx, TNMD, and TSP-4 in tenocytes were significantly higher than that in MSCs, but lower than in tendon tissue whereas expression pattern of TNC, Col I and III showed different pattern with each other. CONCLUSION: This study demonstrated that 6 commonly used tendon-specific markers were mainly expressed in tendon tissue, but that expression level and pattern of the tendon-specific markers with respect to kinds of tissues, culture duration of tenocytes and sources of MSCs.

Favorable Functional Recovery and Stem Stability after Hip Arthroplasty with a Short Metaphyseal Stem in Elderly Patients with Osteoporotic Femoral Neck Fractures / 대한고관절학회지

PURPOSE: Short stems have recently become widely used; however, concerns about the initial secure fixation of a short stem in osteoporotic bone remain. The aim of this study was to evaluate the short-term clinical and radiological results of using a short cementless metaphyseal stabilizing tapered stem for senile osteoporotic femoral neck fractures. MATERIALS AND METHODS: Thirty-eight arthroplasties (31 bipolar hemiarthroplasties and 7 total hip arthroplasties) were performed for osteoporotic femoral neck fractures in patients older than 65 years (10 males and 28 females). The mean age was 76.1 years and the mean follow-up was 2.9 years. We retrospectively evaluated clinical results, focusing on walking performance, thigh pain, and radiologic results, with special regard to signs of stem stability and osteointegration. RESULTS: Mean Harris hip score was 84.3 points and 68.4% of patients regained their preoperative walking performance. No patients complained about thigh pain. No osteolysis or loosening was observed during the follow-up, and all but 1 stem showed signs of stable bone ingrowth. CONCLUSION: Short, metaphyseal stabilizing tapered stems could be a reliable treatment option for osteoporotic femoral neck fractures.

Comparative Analysis of Platelet-rich Plasma Effect on Tenocytes from Normal Human Rotator Cuff Tendon and Human Rotator Cuff Tendon with Degenerative Tears

BACKGROUND: Platelet-rich plasma (PRP) stimulates cell proliferation and enhances matrix gene expression and synthesis. However, there have been no comparative study of the PRP effect on the normal and degenerative tenocytes. The purpose of this study was to compare the effect of PRP on tenocytes from normal and degenerative tendon. METHODS: Tendon tissues were obtained from patients undergoing arthroscopic repair (n=9) and from healthy donors (n=3). Tenocytes were cultured with 10% (vol/vol) platelet-poor plasma, PRP activated with calcium, and PRP activated with calcium and thrombin. The total cell number was assessed at days 7 and 14. The expressions of type I and III collagen, decorin, tenascin-C, and scleraxis were evaluated by quantitative real-time reverse transcriptase polymerase chain reaction. The total collagen and glycosaminoglycan (GAG) synthesis was evaluated at days 7 and 14. RESULTS: No differences were observed between the groups at day 7, but cell proliferation was remarkably increased in tenocytes from the degenerative tendon at day 14. In both tenocyte groups, the gene expressions of type I and III collagen were up-regulated. GAG synthesis was greater in the normal tendon, whereas the expressions of decorin and tenascin-C were increased in tenocytes from the degenerative tendon. Tenocytes from the degenerative tendon had higher fold-change of GAG synthesis and a lower collagen III/I ratio than normal tenocytes. CONCLUSIONS: PRP promoted the cell proliferation and enhanced the synthesis of tendon matrix in both groups. PRP has a greater positive effect on cell proliferation, matrix gene expression and synthesis in tenocytes from degenerative tendon.

The Result of Revision Total Hip Arthroplasty in Patients with Metallosis Following a Catastrophic Failure of a Polyethylene Liner

BACKGROUND: Wear cannot be completely prevented after total hip arthroplasty. If severe polyethylene (PE) liner wear develops, the so-called catastrophic failure occurs and metallosis develops. We postulated that longevity of the new implant may be affected after revision surgery for metallosis following a catastrophic failure of a PE liner due to the substantial amount of PE wear particles and infiltration of the metal particles in this catastrophic condition. METHODS: Twenty-three hips of 23 patients were identified because they showed metallosis during revision total hip arthroplasties performed in Seoul National University Hospital between January 1996 and August 2004. They were followed for at least 6.5 years after the index revision total hip arthroplasty. The clinical and radiological results of revision total hip arthroplasties in these patients were evaluated. RESULTS: The median Harris hip score increased from 60 points before revision total hip arthroplasties to 90 points at the final follow-up. Osteolysis was detected at an average of 9.3 years after revision total hip arthroplasties in 13 hips and acetabular cup loosening at average 9.8 years after revision total hip arthroplasties in 9 hips. With radiographic evidence of osteolysis and loosening as the end points, the 15-year survival rates were 28.2% and 56.0%, respectively. CONCLUSIONS: The survival rate of revision total hip arthroplasty in patients with metallosis following a catastrophic failure of a PE liner was low.

Aspergillus Septic Arthritis of the Hip in an Immunocompetent Middle-aged Female with Undiagnosed Recurrent Pulmonary Aspergillosis / 대한고관절학회지

We present a case of Aspergillus septic hip arthritis in an immunocompetent patient with undiagnosed recurrent pulmonary aspergillosis who underwent arthroscopic surgery. Biopsy specimens of synovium revealed fungal hyphae, confirming Aspergillus infection. Aspergillus septic hip arthritis can occur in immunocompetent patients, and arthroscopy can be a noninvasive surgical option in these cases.

Epidemiology of Hip Replacements in Korea from 2007 to 2011

We analyzed national data collected by the Health Insurance Review and Assessment Service in Korea from 2007 to 2011; 1) to document procedural numbers and procedural rate of bipolar hemiarthroplasty (BH), primary and revision total hip arthroplasties (THAs), 2) to stratify the prevalence of each procedure by age, gender, and hospital type, and quantified, 3) to estimate the revision burden and evaluate whether the burden is changed over time. Our final study population included 60,230 BHs, 40,760 primary THAs, and 10,341 revision THAs. From 2007 to 2011, both the number and the rate of BHs, primary THAs increased steadily, whereas there was no significant change in revision THAs. Over the 5 yr, the rate of BHs and primary THAs per 100,000 persons significantly increased by 33.2% and 21.4%, respectively. The number of revision THAs was consistent over time. The overall annual revision burden for THA decreased from 22.1% in 2007 to 18.9% in 2011. In contrast to western data, there were no changes in the number and rate of revision THAs, and the rates of primary and revision THAs were higher for men than those for women. Although 5 yr is a short time to determine a change in the revision burden, there have been significant decreases in some age groups.

Subchondral Insufficiency Fracture of the Femoral Head in Elderly People

We evaluated the clinical course of subchondral insufficiency fracture of the femoral head (SIFFH) and its characteristic findings with special regard to joint space narrowing (JSN). Thirty-one cases of SIFFH of mean age 68.9 yr initially underwent limited weight-bearing conservative treatment. During the follow-up period, the patients with intractable pain underwent total hip arthroplasty (THA). For radiographic evaluation, lateral center-edge angle, JSN and femoral head collapse (FHC) were documented, and the extent of FHC was classified as mild (4 mm). The progression or new development of FHC more than 2 mm was evaluated on sequential plain radiographs. The relationship between radiographic parameters and clinical outcomes were evaluated. THAs were performed in 15 cases (48.4%). There was no significant correlation between clinical outcomes and the extent of initial FHC. However, a significantly larger proportion of patients that underwent THA showed JSN and FHC progression compared to the symptom improvement group. The risk factor significantly associated with failed conservative treatment was JSN (P=0.038; OR, 11.8; 95% CI, 1.15-122.26). Clinical results of conservative treatment for SIFFH in elderly patients are relatively poor. The patients with JSN are at higher risk of failed conservative treatment.

Arthroscopic Treatment for External Snapping Hip / 대한고관절학회지

PURPOSE: The purpose of this study was to evaluate the clinical outcome of arthroscopic treatment for recalcitrant external snapping hip. MATERIALS AND METHODS: Between September 2011 and June 2013, we evaluated 7 patients (10 cases) with snapping hip who were refractory to conservative treatments for at least 3 months. Two patients (4 cases) were impossible to adduct both knees in 90degreesof hip flexion. Surgery was done in lateral decubitus position, under spinal anesthesia. We made 2 arthroscopic portals to operate the patients, and used cross-cutting with flap resection technique to treat the lesion. We performed additional gluteal sling release in those 2 patients (4 cases) with adduction difficulty. Average follow-up length was 19 months (range, 12-33 months). Clinical improvement was evaluated with visual analog scale (VAS), modified Harris hip score (mHHS), and also investigated for presence of limping or other complications as well. RESULTS: The VAS decreased from 6.8 (range, 6-9) preoperatively to 0.2 (range, 0-2) postoperatively, and the mHHS improved from 68.2 to 94.8 after surgery. None of the patients complained of post-operative wound problem or surgical complications. CONCLUSION: The clinical outcome of arthroscopic treatment for recalcitrant external snapping hip was encouraging and all patients were also satisfied with the cosmetic results.

Cementless Total Hip Arthroplasty for Patients with Crowe Type III or IV Developmental Dysplasia of the Hip: Two-Stage Total Hip Arthroplasty Following Skeletal Traction after Soft Tissue Release for Irreducible Hips

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Minimum 5-Year Results of Titanium Tapered Stem with Alumina Bearing in Cementless Total Hip Arthroplasty Using a Modified Direct Lateral Approach / 대한정형외과학회잡지

PURPOSE: The purpose of the current study is to evaluate the clinical and radiographic outcomes of primary total hip arthroplasty (THA) using a single titanium tapered stem with alumina bearing, which was performed through a modified direct lateral approach. MATERIALS AND METHODS: One hundred twenty consecutive primary THAs were performed in 102 patients, and retrospectively reviewed. There were 53 men and 49 women of mean age 54 years, and all patients were followed for a minimum follow-up period of 5 years (range, 5-8.1 years). Clinical outcomes assessment consisted of calculation of the Harris hip score (HHS), and evaluation of the presence of thigh pain or limp. Sequential radiographs were evaluated for implant migration, osteolysis, reactive line, cortical hypertrophy, or evidence of component loosening. RESULTS: At the final follow-up, the mean preoperative HHS of 46 points improved to 94 points; and activity-related thigh pain occurred in two hips, and mild limps in four hips. There was no evidence of implant migration, osteolysis, or component loosening. Audible squeaking was present in two hips, without pain and radiographic abnormality. Dislocation occurred in three hips. CONCLUSION: The minimum 5-year results of titanium tapered stem with alumina bearing in cementless primary THA, using a modified direct lateral approach, were encouraging.

Progression of a Fracture Site Impaction as a Prognostic Indicator of Impacted Femoral Neck Fracture Treated with Multiple Pinning

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Progression of a Fracture Site Impaction as a Prognostic Indicator of Impacted Femoral Neck Fracture Treated with Multiple Pinning

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Femoral Head Fracture without Dislocation by Low-Energy Trauma in a Young Adult

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.

Treatment of Unstable Intertrochanteric Fracture Using Short Barrel Compression Hip Screws and a Trochanteric Stabilizing Plate / 대한정형외과학회잡지

PURPOSE: To assess the effectiveness of additional fixation using a trochanter stabilizing plate for the case of an unstable intertrochanteric fracture of the femur. MATERIALS AND METHODS: Between February 2003 and February 2009, one hundred twenty-one consecutive patients with unstable intertrochanteric fractures were treated with CHSs and a TSP with or without additional screws and wiring. The follow up period was an average of twenty-eight months (range: six to sixty-one months). The fractures were classified according to the Jensen classification. We retrospectively evaluated the fracture healing time, the sliding length, the incidence of fixation failure and clinical failure, and the functional recovery. RESULTS: The mean time to radiologic bony union was 16.2weeks. The average amount of lag screw sliding was 8.4 mm. Overall, 119 of 121 patients had bony union and 2 patients showed nonunion. Mechanical failure was noted in 5 patients and 8 patients showed clinical failure. Ninety-four patients (78%) had at least returned to their pre-fracture level of walking ability. CONCLUSION: Fixation with compression hip screws (CHSs) and a trochanter stabilizing plate (TSP) for treating unstable intertrochanteric fracture of the femur seemed to be helpful for decreasing excessive sliding and the rate of fixation failure. Short barrel CHSs and TSP fixation with additional screws and wiring are necessary for treating unstable intertrochanteric fracture of the femur, and especially for the cases with a large posterior greater trochanteric fragment or a displaced lesser trochanter.

Operations about Hip in Human Immunodeficiency Virus-Positive Patients

BACKGROUND: The number of human immunodeficiency virus (HIV)-infected patients is increasing constantly, and it is well known that there is a significantly high prevalence of osteonecrosis of the femoral head in HIV-infected patients. Therefore, it is important to develop methods that can ensure the safety of both the patients and medical personnel who participate in surgery on HIV-infected patients. Recently, the authors performed 8 procedures on 5 HIV-infected patients. This paper reports our experience. METHODS: This study examined the medical records and radiological studies of 5 HIV-infected patients who had undergone surgery around the hip joint from January, 2005 to September, 2007. During the procedures, their mean age was 38.6 years (range, 23 to 53 years) and all were male. Four of them were under an anti-retroviral therapy program. The reasons for the operations were nonunion of the femoral shaft after trauma in two patients and osteonecrosis of both femoral heads in three. One autologous bone grafting, one screw fixation with autologous bone grafting, five total hip replacement arthroplasties, and one multiple drilling were performed. All procedures were carried out according to the guidelines of HIV infection control made by the Korea Centers for Disease Control and Prevention. The mean follow-up period was 16.6 months (range, 4 to 37 months). RESULTS: The preoperative CD4 count was 130 in one patient, and 200 to 499 in the other 4. The viral loads were 15100 and 420 in two patients, and negative in the other 3. Bony union was achieved in those who had undergone autologous bone grafting. There were significant improvements in both the Harris Hip Score and functional state in those who had total hip replacement arthroplasty. There were no immediate postoperative complications, such as infection. During the follow-up period, one patient died from esophageal variceal bleeding. However, no surgery-related complications were observed in the other 4 patients. CONCLUSIONS: There were no significant complications in HIV-infected patients after the operations around the hip joint when their preoperative immunity was optimal. In addition, the safety of medical personnel can be assured when the operation is performed in line with the guidelines of HIV infection control.

Dual-Modal Nanoprobes for Imaging of Mesenchymal Stem Cell Transplant by MRI and Fluorescence Imaging

OBJECTIVE: To determine the feasibility of labeling human mesenchymal stem cells (hMSCs) with bifunctional nanoparticles and assessing their potential as imaging probes in the monitoring of hMSC transplantation. MATERIALS AND METHODS: The T1 and T2 relaxivities of the nanoparticles (MNP@SiO2[RITC]-PEG) were measured at 1.5T and 3T magnetic resonance scanner. Using hMSCs and the nanoparticles, labeling efficiency, toxicity, and proliferation were assessed. Confocal laser scanning microscopy and transmission electron microscopy were used to specify the intracellular localization of the endocytosed iron nanoparticles. We also observed in vitro and in vivo visualization of the labeled hMSCs with a 3T MR scanner and optical imaging. RESULTS: MNP@SiO2(RITC)-PEG showed both superparamagnetic and fluorescent properties. The r1 and r2 relaxivity values of the MNP@SiO2(RITC)-PEG were 0.33 and 398 mM-1 s-1 at 1.5T, respectively, and 0.29 and 453 mM-1 s-1 at 3T, respectively. The effective internalization of MNP@SiO2(RITC)-PEG into hMSCs was observed by confocal laser scanning fluorescence microscopy. The transmission electron microscopy images showed that MNP@SiO2(RITC)-PEG was internalized into the cells and mainly resided in the cytoplasm. The viability and proliferation of MNP@SiO2(RITC)-PEG-labeled hMSCs were not significantly different from the control cells. MNP@SiO2(RITC)-PEG-labeled hMSCs were observed in vitro and in vivo with optical and MR imaging. CONCLUSION: MNP@SiO2(RITC)-PEG can be a useful contrast agent for stem cell imaging, which is suitable for a bimodal detection by MRI and optical imaging.

Surgical Approach to the Hip: Direct Lateral Approach

The direct lateral approach was first described and named the transgluteal approach by Bauer in 1979 and was popularized by Hardinge K in 1982. In total hip arthroplasty, the direct lateral approach offers distinct advantages for the orientation of implants, access to both the acetabulum and proximal femur, and the preservation of soft tissue continuity between the gluteus medius and vastus lateralis muscle group. It can also be quite versatile, even in cases requiring extensive exposure, such as revision arthroplasty. The disadvantages include a risk of superior gluteal nerve injury, disruption of the repaired abductor mechanism, and postoperative heterotopic ossification. This review describes the surgical exposure of the direct lateral approach as well as the advantages and potential complications of the direct lateral approach.

Acromion Morphology in Coronal and Sagittal Plane; Correlation with Rotator Cuff Syndrome

PURPOSE: We evaluated the correlation of the anatomic parameters of the acromion those represent on the magnetic resonance image (MRI) of impingement syndrome. MATERIALS AND METHODS: From June, 2004 to December, 2005, 71 cases were surgically proven to be impingement syndrome, and the anterior acromial hooking angle, the lateral acromial hooking angle (AAHA and LAHA) and the acromial hooking index (AHI: the sum of the AAHA and LAHA) were compared to 16 control cases. At the same period, 55 cases were surgically proven to be partial or full thickness rotator cuff tear, and age, gender and twelve anatomic parameters, including the acromial type, the acromial angle, the anterior covering, the acromial slope, the AAHA, the lateral acromial angle, the acromial torsional angle, the lateral acromial angulation, the LAHA, the lateral covering, the acromiohumeral distance and the AHI were assessed. RESULTS: The AAHA and AHI were increased as impingement syndrome proceeded. The acromial type and acromial angle, and the AAHA, LAHA and AHI showed significant differences between the controls and the rotator cuff tear patients on univariant analysis. On multivariant analysis, gender was most strongly correlated with rotator cuff tear. Age, AAHA and the acromial angle showed similar correlation, respectively. CONCLUSION: The coronal acromial shape is correlated with rotator cuff tear, and it is important to correct the lateral acromial shape when performing acromioplasty.

Acromial Morphology in Different MR Oblique Sagittal Slices: Correlation with Rotator Cuff Disorder

PURPOSE: On the hypothesis that the acromion morphology is changed according to the its site, we identified the morphology of the acromion on the oblique slices of MRI and we investigated the association of the acromial shape with the clinical stages of rotator cuff disorder on the magnetic resonance (MR) images. In addition, we compared the acromion morphology on MRI and simple X-rays. MATERIAL AND METHODS: The MR images of seventy one patients with rotator cuff disorder and who underwent arthroscopic surgery were compared with that of a control group of sixteen patients who didn't have rotator cuff disorder on MRI. On three subsequent oblique sagittal slices from the lateral edge of the acromion (S1, S2 and S3), each acromion morphology on the MRI slices was classified according to Epstein et al: flat, curved or hooked. We investigated the changing parttern of the acromion shape and we compared the acromion shape on MRI and that on simple X-rays. We classified the rotator cuff tear by the severity: bursitis, partial thickness tear or full thickness tear. We investigated which acromial type on the MRI oblique slice was associated with the severity of rotator cuff disease. RESULTS: Changes of the acromial shape occurred in 54 patients (76.1%). The most frequent pattern was that the types are same on S1 and S2 and different on S3 (22 cases, 31.0%). The acromial type on S1 and S2 was significantly associated with the severity of rotator cuff disorder (p=0.001 and 0.022), respectively. There was no reliability of the acromial shape on MRI and roentgenography (p>0.05). CONCLUSION: The type of acromion changed from lateral to medial. Among the three positions, the shape of the acromion on S1 and S2 had meaningful correlation with the clinical stage of rotator cuff disorder. There was no statistical correlation of the acromial shape between MRI and simple X-ray.