Kang-Sup Yoon

High incidence of loosening of the femoral component in legacy posterior stabilised-flex total knee replacement

We have examined the results obtained with 72 NexGen legacy posterior stabilised-flex fixed total knee replacements in 47 patients implanted by a single surgeon between March 2003 and September 2004. Aseptic loosening of the femoral component was found in 27 (38%) of the replacements at a mean follow-up of 32 months (30 to 48) and 15 knees (21%) required revision at a mean of 23 months (11 to 45). We compared the radiologically-loose and revised knees with those which had remained well-fixed to identify the factors which had contributed to this high rate of aseptic loosening. Post-operatively, the mean maximum flexion was 136 degrees (110 degrees to 140 degrees) in the loosened group and 125 degrees (95 degrees to 140 degrees) in the well-fixed group (independent t-test, p = 0.022). Squatting, kneeling, or sitting cross-legged could be achieved by 23 (85%) of the loosened knees, but only 22 (49%) of the well-fixed knees (chi-squared test, p = 0.001). The loosened femoral components were found to migrate into a more flexed position, but no migration was detected in the well-fixed group. These implants allowed a high degree of flexion, but showed a marked rate of early loosening of the femoral component, which was associated with weight-bearing in maximum flexion.

Mesenchymal Stem-Cell Transplantation for Hypoxic-Ischemic Brain Injury in Neonatal Rat Model

Neonatal hypoxic-ischemic brain injury (HIE) remains a major cause of neurologic disabilities. However, many experimental therapies have shown limited successes. We assessed whether human mesenchymal stem cells (MSCs) could be transplanted in the HIE rat brain to improve neurologic disabilities. P7 SD rats were either subjected to left carotid artery ligation and hypoxic exposure [hypoxia-ischemia (HI)] or sham operation and normoxic exposure (sham). On P10, rat pubs received either PKH26-labeled MSCs or buffer via intracardial injection, resulting in four experimental groups: sham-buffer, sham-MSC, HI-buffer, and HI-MSC. Cylinder test and accelerating rotarod test were performed 14, 20, 30, and 40 d after injection. Six weeks after injection, cresyl violet and double immunofluorescence staining were performed. MSCs were transplanted to the whole brain mainly after HI. Glial fibrillary acidic protein and OX42 were more abundantly colocalized with MSC than neuronal specific nuclear protein or myelin basic protein. There were no significant differences in the total amounts and cell types between the lesioned and nonlesioned hemisphere. The lesioned hemispheric volume was decreased after HI (p = 0.012) but not restored by MSC. Neurologic performance was significantly impaired only on the cylinder test after HI (p = 0.034), and MSC transplants improved it (p = 0.010). These suggest MSC can be a candidate for the treatment of neonatal HIE.

Differences in donor CXCR4 expression levels are correlated with functional capacity and therapeutic outcome of angiogenic treatment with endothelial colony forming cells

CXCR4 expression is important for cell migration and recruitment, suggesting that the expression levels of CXCR4 may be correlated with functional activity of implanted cells for therapeutic neovascularization. Here, we examined differences between umbilical cord blood (CB) donors in the CXCR4 levels of endothelial colony forming cells (ECFCs), which are a subtype of endothelial progenitor cells (EPCs). We investigated the relationships between CXCR4 expression level and SDF-1alpha-induced vascular properties in vitro, and their in vivo contributions to neovascularization. We found that ECFCs isolated from different donors showed differences in CXCR4 expression that were linearly correlated with SDF-1alpha-induced migratory capacity. ECFCs with high CXCR4 expression showed enhanced ERK and Akt activation in response to SDF-1alpha. In addition, SDF-1alpha-induced migration and ERK1/2, Akt, and eNOS activation were reduced by AMD3100, a CXCR4-specific peptide antagonist, or by siRNA-CXCR4. Administration of high-CXCR4-expressing ECFCs resulted in a significant increase in therapeutic potential for blood flow recovery, tissue healing and capillary density compared to low-CXCR4-expressing ECFCs in hindlimb ischemia. Taken together, the functional differences among ECFCs derived from different donors depended on the level of CXCR4 expression, suggesting that CXCR4 expression levels in ECFCs could be a predictive marker for success of ECFC-based angiogenic therapy.

Revision of Ceramic Head Fracture After Third Generation Ceramic-on-Ceramic Total Hip Arthroplasty

We performed 24 revisions of fractures of third generation ceramic heads. The stem was not changed in 20 revisions; a new ceramic-on-ceramic bearing was used in four and a metal-on-polyethylene bearing in 16. The stem was changed in four revisions; a new ceramic-on-ceramic bearing was used in three and a metal-on-polyethylene bearing in one. During the follow-up of 57.5 months, complications occurred in five hips among the 20 stem retained revisions: a fracture of the new ceramic head in two, metallosis with pseudocyst in two, and femoral osteolysis with stem loosening in one. However, there were no complications in the four revisions where the stem was changed. Revision surgery after ceramic head fracture shows high rates of early complications. We recommend stem revision in cases of THA failure due to fracture of a modern ceramic head.

The slippage-proof knot: a new, nonstacking, arthroscopic, sliding locking knot with a lag bight.

The slippage-proof knot is a new, nonstacking, arthroscopic, sliding knot with a lag bight. The knot is easy to tie and ensures smooth sliding and avoidance of premature locking.

A modified Z-plasty technique for severe tightness of the gluteus maximus.

The majority of reports concern external snapping hips caused by the iliotibial band. Comparatively, little information is available regarding snapping hips caused by a gluteus maximus. Here we show that hip problems caused by a tight gluteus maximus can be treated using a modified Z‐plasty technique. Fourteen hips in seven patients were diagnosed as snapping hips caused by a tight gluteus maximus. The main functional impairment is that when the hips were flexed, legs were abducted widely and could not be adducted. All had functional impairments irresponsive to conservative treatments besides snapping, whether painful or not, and all patients underwent surgery using a modified Z‐plasty technique on the iliotibial band. All patients were followed up and the mean follow‐up was 7 years. All patients had complete resolution of functional impairments, snapping, and pain after surgery. No patient needed revision surgery, and there were no complications, such as, abductor weakness, or irritation over the greater trochanter. We suggest that the intrinsic tendon contracture can cause serious functional impairment in patients with snapping due to a tight gluteus maximus. In this context, a modified Z‐plasty technique offers a good surgical approach.

Effect of intraoperative position used in posterior lumbar interbody fusion on the maintenance of lumbar lordosis

OBJECT The objective in this study was to compare retrospectively the use of different operating tables with different positions for posterior lumbar interbody fusion (PLIF) and the effect on intraoperative and postoperative lumbar lordosis and segmental lordosis. METHODS One hundred seventy-two patients with degenerative disease of the lumbar spine who underwent posterior decompression and PLIF in which a 0 degrees polyetheretherketone cage and pedicle screw fixation were used were evaluated. Ninety-one patients underwent surgery on a Wilson table (Group I) and 81 patients were treated on an OSI Jackson spinal table (Group II). Preoperative standing, intraoperative prone, and postoperative standing lateral radiographs were obtained in each patient. The total lumbar and segmental lordosis were compared and analyzed according to the position in which the patients were placed for their operation. RESULTS The intraoperative total lumbar lordosis was significantly decreased compared with the preoperative value. The postoperative total lumbar lordosis was similar, however, to the preoperative values in both groups. In Group I, the intraoperative segmental lordosis of L2-3 and L3-4 was significantly decreased compared with the pre-operative segmental lordosis. In Group II, the intraoperative segmental lordosis of L3-4, L4-5, L5-S1, and L4-S1 was significantly decreased compared with the preoperative segmental lordosis. The postoperative segmental lordosis of L4-5 was significantly decreased and L2-3 was significantly increased compared with the preoperative lordosis in both groups. CONCLUSIONS Intraoperative position does not affect postoperative total lumbar lordosis and segmental lordosis in short-segment PLIF of the lumbar spine in a retrospective analysis of the surgical procedure to maintain lordosis.

Clinical outcomes of an initial 3-month trial of conservative treatment for femoroacetabular impingement

Background: Femoroacetabular impingement (FAI) can be managed either conservatively or by a surgical correction of the deformity causing impingement. However, there is insufficient evidence to justify an immediate surgical treatment in all symptomatic patients, and the role of a nonoperative treatment is unclear. This study evaluates the role of conservative treatment for FAI. Materials and Methods: 87 patients (102 hips) diagnosed as FAI between January 2011 and May 2012 were included in this retrospective study. All patients underwent an initial 3-month conservative treatment followed by arthroscopic hip surgery if symptoms did not improve. Clinical outcome scores (modified Harris Hip Score, nonarthritic hip score, and Western Ontario and McMaster Universities Arthritis Index) were evaluated at baseline and at the end of followup, and scores were compared between the nonsurgical and surgical groups. Results: The final analysis included 83 patients (55 men, 28 women; 97 hips) because four patients were lost to followup. The average age was 45.1 years and 14 patients had bilateral symptomatic FAI. After an initial conservative treatment averaging 27.5 months (range 24–36 months), 53 hips (54.6%) could perform normal daily activities. The nonsurgical group had significant improvements in all clinical scores at the end of followup (P < 0.001). Forty four hips (45.4%) were unresponsive to conservative treatment and underwent arthroscopic hip surgery with subsequent significant improvements in clinical scores (P < 0.001). At the end of followup, there were no significant differences in clinical scores between the two groups. Conclusion: An initial trial of conservative treatment of sufficient length should be considered for FAI patients before surgical intervention.

Arthroscopic treatment of psoas abscess concurrent with septic arthritis of the hip joint

Purpose: To describe the outcomes of 7 cases of psoas abscess concurrent with septic arthritis of the hip treated by hip arthroscopy alone. Methods: We retrospectively collected the data of patients who underwent arthroscopic drainage of psoas abscess concurrent with septic arthritis of the hip. Arthroscopic debridement was performed in both the central and peripheral hip joint compartments. In all cases, the iliopsoas compartment was accessed from the peripheral compartment through an anterior capsulotomy without limb traction. After debridement and drainage of the iliopsoas compartment, a suction drain tube was placed in the iliopsoas compartment through an enlarged anterior capsulotomy and another tube in the peripheral compartment. Postoperative intravenous antibiotics were administered on the basis of culture results; in cases with no positive culture, empirical antibiotics were administered for 4 to 6 weeks after surgery. Results: 7 patients underwent arthroscopic debridement and drainage for a psoas abscess concurrent with hip joint septic arthritis. Laboratory tests were normalized within 4 weeks after hip arthroscopy in all patients. At a median follow-up of 16 months (range, 13-30 months) after surgery, infection recurrence was absent in all patients. Conclusions: Arthroscopic debridement alone could be an effective treatment alternative to open surgery for psoas abscess concurrent with hip joint septic arthritis.