Jung Ro Yoon

The use of poly(lactic-co-glycolic acid) microspheres as injectable cell carriers for cartilage regeneration in rabbit knees

The use of injectable scaffolding materials for in vivo tissue regeneration has raised great interest because it allows cell implantation through minimally invasive surgical procedures. Previously, we showed that poly(lactic-co-glycolic acid) (PLGA) microspheres can be used as an injectable scaffold to engineer cartilage in the subcutaneous space of athymic mice. The purpose of this study was to determine whether PLGA microspheres can be used as an injectable scaffold to regenerate hyaline cartilage in the osteochondral defects of rabbit knees. A full-thickness wound to the patellar groove of the articular cartilage was made in the knees of rabbits. Rabbit chondrocytes were mixed with PLGA microspheres and injected immediately into these osteochondral wounds. Both chondrocyte transplantations without PLGA microspheres and culture medium injections without chondrocytes served as controls. Sixteen weeks after implantation, chondrocytes implanted using the PLGA microspheres formed white cartilaginous tissues. Histological scores indicating the extent of the cartilaginous tissue repair and the absence of degenerative changes were significantly higher in the experimental group than in the control groups (P < 0.05). Histological analysis by a hematoxylin and eosin stain of the group transplanted with microspheres showed thicker and better-formed cartilage compared to the control groups. Alcian blue staining and Massons trichrome staining indicated a higher content of the major extracellular matrices of cartilage, sulfated glycosaminoglycans and collagen in the group transplanted with microspheres than in the control groups. In addition, immunohistochemical analysis showed a higher content of collagen type II, the major collagen type in cartilage, in the microsphere transplanted group compared to the control groups. In the group transplanted without microspheres, the wounds were repaired with fibro-cartilaginous tissues. This study demonstrates the feasibility of using PLGA microspheres as an injectable scaffold for cartilage regeneration in a rabbit model of osteochondral wound repair.

Comparison of soft-tissue serum markers in stable intertrochanteric fracture: Dynamic hip screw versus proximal femoral nail—A preliminary study

DESIGN Prospective randomised comparative study. OBJECTIVES To analyse and compare serum soft-tissue marker differences after dynamic hip screw (DHS)and proximal femoral nail (PFN) fixation of stable intertrochanteric fractures in the elderly. MATERIALS AND METHODS Twenty elderly patients (>60 years old) with a stable intertrochanteric fracture were enrolled in this study. Patients were divided into two groups of 10 each according to the device used (DHS or PFN). All 20 patients had a stable intertrochanteric fracture, and all were operated on by the same surgeon using minimal invasive approach. A biochemical comparison of soft-tissue serum markers was performed. The serum markers examined were haemoglobin (Hb), haematocrit (Hct), creatine kinase (CK), myoglobin (MYO), troponin I and C-reactive protein (CRP), and their levels were determined before surgery, and 1, 8, 16, 24, 36, 48 and 72 h after surgery. Differences between the DHS and PFN groups were compared. RESULTS No inter-group differences were observed with respect to preoperative demographics,operation time, incision length or blood loss. In terms of serum markers, both methods showed similar patterns of change for CK, MYO and CRP pre- to post-operatively. In addition, pre- and postoperative Hb and Hct levels were similar. Furthermore, no inter-group differences were observed between the absolute values of serum markers at any point. CONCLUSION The absolute values and temporal changes of serum markers were similar in the two study groups. These findings suggest that DHS and PFN fixation of stable intertrochanteric fractures produce similar levels of soft-tissue damage.

A validation study for estimation of femoral anteversion using the posterior lesser trochanter line: an analysis of computed tomography measurement.

The aim of this study was to introduce a simple and reliable intraoperative reference guide to reproduce the normal femoral anteversion during total hip arthroplasty (THA). We hypothesized that the posterior lesser trochanter line (PLTL) could be a useful guide for estimating femoral anteversion during THA. We conducted a study of 56 men (112 hips) to evaluate the relationship between the PLTL and the femoral anteversion using computed tomography scans. The mean femoral anteversion was 9.0° ± 8.1° (range, -16.2° to 32.9°). The PLTL angle correlated (r(2) = 0.12, P < 0.05) with the femoral anteversion. We found a constant relationship between the PLTL and femoral anteversion, and the PLTL may be used as a guide for estimating the femoral stem anteversion during femoral stem fixation.

Minimally Invasive Plate Osteosynthesis (MIPO) for Periprosthetic Fracture after Total Ankle Arthroplasty: A Case Report

Level of Evidence: V, Expert Opinion

Reliability of a PowerPoint method for wear measurement after total hip arthroplasty: a retrieval study using 3-dimensional laser scanning.

The purpose of this study was to evaluate the reliability of the PowerPoint (PP) (2007 Version; Microsoft, Redmond, Wash) method for measuring polyethylene liner wear after total hip arthroplasty. Seventeen retrieved polyethylene liners were included in this study. Wear volumes were calculated using the PP, the Dorr and Wan, and 3-dimensional (3D) laser scanning methods. Spearman correlation coefficients for wear volume results indicated strong correlations between the PP and 3D laser scanning methods (range, 0.89-0.93). On the other hand, Spearman correlation analysis revealed only moderate correlations between the Dorr and Wan and 3D laser scanning methods (range, 0.67-0.77). The PP method can be used to monitor linear wear after total hip arthroplasty and could serve as an alternative method when computerized methods are not available.

Peripheral Nerve Sheath Tumor of the Medial Plantar Nerve Without Tarsal Tunnel Syndrome: A Case Report

UNLABELLED Peripheral nerve sheath tumors are relatively uncommon soft tissue tumors, and the incidence of peripheral nerve sheath tumors localized to the plantar surface of the foot, without symptoms of tarsal tunnel syndrome, is even more rare. In this report, we present the rare case of a patient with a peripheral nerve sheath tumor originating from the medial plantar nerve in the plantar vault. The tumor was enucleated and fully excised under microscopic inspection using fine-tipped instrumentation, without en bloc resection of the associated nerve trunk. Surgeons should consider peripheral nerve sheath tumor as a cause of plantar foot pain, despite the rarity of this disorder. LEVEL OF CLINICAL EVIDENCE 4.

Intra-articular patterns of bucket handle meniscal tears and its relation to reducibility.

Background The purpose of this study was to assess the intra-articular patterns in the rotational deformities of bucket handle meniscal tears (BHMTs) based on arthroscopic findings and their clinical relevance. Methods From 2004 to 2009, 42 patients with a BHMT diagnosed by magnetic resonance imaging underwent arthroscopic surgery. The arthroscopic data (all procedures were recorded) were evaluated retrospectively, and BHMTs were classified according to the rotational directions of centrally displaced fragments. To assess the reliability of the agreement in this classification, 2 orthopedic surgeons re-classified BHMTs, 1 week after first trial. Intra- and interobserver reliabilities were assessed using kappa statistics. In addition, we address specific tear patterns, associated anterior cruciate ligament injury, medio-lateral difference, reducibility, chronicity, and reparability. Results Most of the tears could be categorized into one of 3 morphologic patterns. Of the tears, 4.8% could not be categorized. BHMTs were classified, based on the rotational directions of centrally displaced fragments, as follows; the upward rotation group (type 1), the downward rotation group (type 2) and the reverse group (type 3). The most common intra-articular pattern was type 1 (29 patients, 69%). The occurrence of the other patterns was: type 2 in 7 patients (16.7%), type 3 in 4 patients (9.5%); we were not able to make a classification of type in 2 patients (4.8%). Intra-observer reliability was 0.86 in terms of kappa statistics, which implies almost perfect agreement. Mean interobserver reliability (0.73) showed substantial agreement. Type 1 and 2 tears were easily reduced, whereas all type 3 tears (4/4) needed additional procedures to achieve reduction. Conclusions Based on arthroscopic findings, we describe a comprehensive BHMT classification scheme that encompasses 95.2% of all tears. Tear type was correlated with reducibility.

Arthroscopic Treatment of Acute Septic Arthritis After Meniscal Allograft Transplantation

We present the 30-month follow-up results of an acute septic arthritis of the knee after meniscal allograft transplantation, which was successfully treated with graft retention. A 21-year-old man presented with a 4-month history of right knee pain following arthroscopic subtotal lateral meniscectomy. Plain radiographs showed there was no arthritic change with neutral limb alignment. Fourteen days after meniscal allograft transplantation, septic arthritis was confirmed with positive cultures for Staphylococcus epidermidis, and arthroscopic debridement and irrigation were performed. The suggested procedures of our treatment regimen include arthroscopic debridement and irrigation with >or=10 L of normal saline as soon as possible after diagnosis or a clinical suspicion is reached, repeated irrigation under the local anesthesia and intravenous antibiotics until clinical symptoms and laboratory results improve. The decision to repeat the debridement was based on clinical and laboratory results. We reevaluated the patients the third or fourth day after every arthroscopic treatment. At last follow-up, 2 years after the final operation, the patient had no clinical sign of infection. Erythrocyte sedimentation rate and C-reactive protein level were normal and plain radiographs indicated no arthritic change. Further the patient had full pain-free range of knee motion. At this time the Lysholm knee score was 89 and the Tegner score was 5. Magnetic resonance imaging 30 months postoperatively revealed slight (3 mm) extrusion without tear. This case is notable because it shows that early aggressive arthroscopic debridement and repeated irrigation with graft retention can be an effective treatment regimen in selected cases.

Myopericytoma around the knee: mimicking a neurogenic tumour

Abstract Myopericytoma is a rare, usually benign soft tissue tumour that arises most commonly in the dermis and subcutaneous soft tissue of the lower extremities. In this article, we present an unusual case of myopericytoma occurring in the deep soft tissue around the knee that mimicked a neurogenic tumour. Myopericytoma can be confused with neurogenic tumour when located in deep soft tissue and adjacent to nerve bundles. Preoperative MRI and colour Doppler ultrasound may help differentiate myopericytoma from neurogenic tumour by revealing the hypervascular nature of the tumour. Level of evidence V.

Posterior-stabilized inserts are preferable to cruciate-substituting ultracongruent inserts due to more favourable kinematics and stability

PurposeIt is unknown whether the conforming superiority of ultracongruent (UC) inserts over posterior stabilized (PS) inserts, due to an increased anterior lip for prevention of anterior displacement of the condyles during knee flexion, leads to better knee scores or greater knee stability in arthroplasty patients. This meta-analysis compared clinical outcomes, intraoperative kinematics, sagittal stability, and range of motion (ROM) between groups with either UC or PS inserts in primary total knee arthroplasty (TKA).MethodsStudies that recorded clinical outcomes, intraoperative kinematics, sagittal stability, and ROM in patients who underwent primary TKA with UC or PS inserts were included in the meta-analysis. Subgroup analyses based on differences in flexion angles were performed for intraoperative kinematics.ResultsThirteen studies met the criteria for inclusion in the meta-analysis. The UC and PS insert groups reported similar pain scores (95% CI − 0.15 to 0.16; n.s.) and function scores (95% CI − 0.30 to 0.14; n.s.). In contrast, femoral rotation during flexion (95% CI − 0.06 to 6.35; p = 0.05), posterior femoral translation during flexion (95% CI − 2.74 to − 0.15; p = 0.03), tibial sagittal laxity at 90° (95% CI 2.91 to 7.72; p < 0.0001), and ROM (95% CI − 4.84 to − 1.53; p = 0.0002) differed significantly between the groups. Subgroup analyses revealed that the pooled data for femoral rotation were significantly different between groups: 60°, 4.09 (p < 0.00001); 90°, 7.94 (p < 0.00001); and 120°, 8.16 (p < 0.00001). Furthermore, pooled data for posterior femoral translation were significantly different between groups: 90°, − 3.70 (p < 0.00001); and 120°, − 3.96 (p < 0.00001).ConclusionsThere were no significant differences in clinical outcomes between the groups with UC and PS inserts. However, the UC insert group showed significantly greater external femoral rotation, less posterior femoral translation, greater tibial laxity in the sagittal plane, and less ROM than the PS insert group. Based on the results of the current meta-analysis, in substituting the PCL, PS inserts are preferable to UC inserts due to more favourable kinematics and stability, even though both inserts have equivalent clinical outcomes.Level of evidenceTherapeutic study, Level II.