Aims

Although there are various pelvic osteotomies for acetabular dysplasia of the hip, shelf operations offer effective and minimally invasive osteotomy. Our study aimed to assess outcomes following modified Spitzy shelf acetabuloplasty.

Aims

There are concerns regarding complications and longevity of total elbow arthroplasty (TEA) in young patients, and the few previous publications are mainly limited to reports on linked elbow devices. We investigated the clinical outcome of unlinked TEA for patients aged less than 50 years with rheumatoid arthritis (RA).

The pathology of the posterior acetabular legion in femoroacetabular impingement (FAI) syndrome, so called “contre-coup region”, is still unclear. ¹⁸F-fluoride positron emission tomography (PET) is a functional imaging modality, which reflects the osteoblast activity. Recent technological advances in PET combined with computed tomography (CT) imaging allowed us to obtain detailed 3-dimensional (3D) morphological information. We evaluated the abnormal uptake of ¹⁸F-fluoride PET/CT on posterior acetabular lesion in FAI syndrome cases. We enrolled forty-one hips from 41 patients who were diagnosed as FAI syndrome and were performed ¹⁸F-fluoride PET/CT between October 2014 and October 2016. In each hip, the maximum standardized uptake value (SUV_max) on the posterior acetabular was measured. The cases were divided into 4 groups; cam-type (11 cases), pincer-type (7), combined-type (11), dysplastic developmental hip (DDH) with cam morphology (12). The average SUV_max of the pincer-type was significantly smaller than that of the other 3 groups (p < .05). The percentage of the cases with SUV_max ≥ 6 was 81.8% in cam-type, 28.6% in pincer-type, 90.9% in combined-type, 91.7% in DDH with cam morphology. Furthermore, the average degree of α angle of the cases of SUV_max ≥ 6 was significantly higher than that of the cases of SUV_max < 6 (p = .005). Although actual biomechanical mechanism in contre-coup region is still controversial, this result indicated that the cam morphology related to the posterior acetabular lesion with accelerated bone metabolism.

In this study, we evaluated the labrum tear using radial sequence 3D Multiple Echo Recombined Gradient Echo (MERGE) MRI without arthrography based on modified Czerny's classification, comparing with actual arthroscopic findings. A total of 61 hips including 27 hips of femoroacetabular impingement (FAI), 19 hips of borderline development dysplasia of the hip (BDDH) and 15 hips of early stage osteoarthritis (OA) were enrolled this retrospective study. MRI findings evaluated in each three regions of interest; anterior region, anterolateral region, and lateral region. The cases with severe degeneration that is not concordant with any original Czerny's classification is defined as stage4. We compared MRI findings with arthroscopic findings and calculated the sensitivity, specificity, and likelihood ratio in terms of the existence of labrum tear. MRI findings revealed labrum tear more frequently in anterolateral than lateral (p<0.001). Especially in FAI group, labrum tear was more frequently observed by MRI in anterolateral than lateral (p=0.006). In comparison with MRI findings and arthroscopic findings, the sensitivity was 97%, specificity was 79% and likelihood ratio was 4.59 as average of all regions in terms of the existence of labrum tear. In each region, sensitivity and specificity was 97% and 50% in anterior, 97% and 100% specificity in anterolateral, 94% and 81% in lateral, respectively. Thus, MERGE MRI revealed excellent sensitivity and specificity for diagnosis of labrum tear, especially in anterolateral region. The cases with severely degenerated labrum were classified as newly defined stage 4, which was recognized frequently in OA cases.

Infection is one of the most serious complications of orthopedic surgery, particularly in implant-related procedures. Minimum inhibitory concentration (MIC) for identified bacteria is an important factor for successful antibiotic treatment. We investigated the MIC of antibiotics in Staphylococcus species from orthopedic infections, comparing with isolates from respiratory medicine. Staphylococcus species isolated in our laboratory from January 2013 to July 2016 were retrospectively reviewed. The MIC of vancomycin (VCM), arbekacin (ABK), teicoplanin (TEIC), linezolid (LZD), and rifampicin (RFP) was reviewed. Differences in the MIC of each antibiotic in orthopedic and respiratory samples were determined. A total of 259 isolates were evaluated (89 orthopedic, 170 respiratory). Staphylococcus aureus was the most commonly identified species (58%). In comparison with orthopedic samples, the number of isolates with a VCM MIC <0.5 μg/ml in methicillin sensitive staphylococcus aureus (MSSA) was significantly higher in respiratory isolates, while a MIC of 2 μg/ml was significantly lower (P = 0.0078). The proportion of isolates with a VCM MIC of 2 μg/ml in methicillin-resistant coagulase-negative staphylococci (MRCNS) was significantly higher in orthopedic isolates than that seen in respiratory isolates of methicillin-resistant staphylococcus aureus (MRSA; P < 0.001). When comparing MRCNS and other orthopedic Staphylococci, the rate of RFP MIC >2 μg/ml in MRCNS isolates was significantly higher (P = 0.0058). The MIC of VCM in Staphylococcus species from orthopedic infection was higher than that of respiratory samples, particularly in MRCNS from implant-related samples. MRCNS showed a significantly higher rate of resistance for RFP versus other orthopedic isolates.

While stable long-term clinical results have been achieved in total joint arthroplasty, periprosthetic joint infection (PJI) has been actualized as difficult issue in this decade. For accurate diagnosis, it is important to establish standard criteria such as MSIS criteria, and it is prevailing now. As an issue involving PJI, however, the existence of viable, but non-culturable (VNC) bacteria must be noticed. It is difficult to identify the VNC state infection, because microbiologic culture result shows negative and other markers tend to be negative. Here, molecular diagnosis based on polymerase chain reaction (PCR) has certain role as potential diagnostic tools for such VNC infection. We have applied a real-time PCR system for the diagnosis of PJI, which is able to detect methicillin-resistant Staphylococcus (MRS) and distinguish gram-positive from gram-negative bacteria. The prominent advantage is that PCR is the singular way to identify MRS in such culture negative cases. Recent development of full-automatic PCR system may improve the time efficiency for routine application. In this presentation, we will show the overall sensitivity and specificity of our PCR system for diagnosing PJI and discuss the current problem and future prospect.

Aims

This study was conducted to investigate the influence of surgical experience on the outcomes and component positioning of total knee arthroplasty (TKA). We compared the outcomes and component positioning of simultaneous bilateral TKAs performed by supervisors and trainee surgeons.

Aims

To determine the normal values and usefulness of the C1/4 space available for spinal cord (SAC) ratio and C1 inclination angle, which are new radiological parameters for assessing atlantoaxial instability in children with Down syndrome.

Objectives

In total hip arthroplasty (THA), the cementless, tapered-wedge stem design contributes to achieving initial stability and providing optimal load transfer in the proximal femur. However, loading conditions on the femur following THA are also influenced by femoral structure. Therefore, we determined the effects of tapered-wedge stems on the load distribution of the femur using subject-specific finite element models of femurs with various canal shapes.

Introduction

Resorptive bone remodeling secondary to stress shielding has been a concern associated with cementless total hip arthroplasty (THA). At present, various types of cementless implants are commercially available. The difference in femoral stem design may affect the degree of postoperative stress shielding. In the present study, we aimed to compare the difference in bone mineral density (BMD) change postoperatively in femurs after the use of 1 of the 3 types of cementless stems.

Introduction

The decreased bone mass or local osteoporosis at the proximal femur is often recognized in patients of rheumatoid arthritis (RA). In total hip arthroplasty (THA), the cancellous bone will be lost when rasping technique is applied for the preparation of stem insertion. In addition, cutting or elongation for contracted muscles around the hip joint can be required to insert the stem. To avoid these problems, the non-broaching, non-rasping impaction technique for the stems was applied in THA for the patients with RA. We report clinical and radiographic results of this method.

INTRODUCTION

Several papers have reported the efficacy of an imageless navigation system in acetabular cup orientation during total hip arthroplasty (THA). Also, an imageless navigation system is useful for recovering leg length discrepancy. However, no study has evaluated the accuracy of the stem antetorsion angle (SAA) with an imageless navigation system in THA. The purpose of this study was to evaluate the accuracy of the stem antetorsion angles, which were measured by CT with the CT-free navigation system. Also, we evaluate the factors that affect the inaccuracy.

Objective

It is known that stress shielding frequently occurs after total hip arthroplasty (THA). However, the status of bone metabolism in stress shielding region is not still clear. ¹⁸F-fluoride positron emission tomography (PET) is a useful tool for the quantitative evaluation of bone metabolism, which uptake relates with the activity of bone formation by osteoblast. In this study, we evaluated the status of bone turnover in stress shielding region using ¹⁸F -fluoride PET.

Introduction

Selection of an optimum thickness of polyethylene insert in total knee arthroplasty (TKA) is important for the good stability and range of motion (ROM). The purpose of this study is to investigate the amount of change of ROM as the thickness of trial insert increase.

INTRODUCTION

Implantation of total hip arthroplasty (THA) components caused a significant alteration in stress environment. Several studies have reported that bone mineral density (BMD) decreases after THA, especially in the proximal femur. This phenomenon is explained as an adaptive remodeling response of bone tissue to a significant alteration in its stress environment.

SL-PLUS MIA stem (Smith & Nephew Orthopaedics AG) is a modified implant of Zweymuller type SL-PLUS standard stem (Smith & Nephew Orthopaedics AG). The major change is an omission of the trochanteric wing, which enables a bone-sparing and may lead to changes of femoral stress distribution and rotational stability. The change of stress distribution in the femur could affect BMD after THA.

In the present study, we constructed finite element (FE) models of femurs and stems before and at 1week after THA and analyzed equivalent stresses in the femur. In addition, we measured BMD in the femur by dual-energy X-ray absorptiometry (DEXA) after THA. The purpose of this study was to investigate the equivalent stress in the femur and to compare the results of the FE analyses with changes in BMD after THA.

In this study we used subject-specific finite element analysis to investigate the mechanical effects of rotational acetabular osteotomy (RAO) on the hip joint and analysed the correlation between various radiological measurements and mechanical stress in the hip joint.

We evaluated 13 hips in 12 patients (two men and ten women, mean age at surgery 32.0 years; 19 to 46) with developmental dysplasia of the hip (DDH) who were treated by RAO.

Subject-specific finite element models were constructed from CT data. The centre–edge (CE) angle, acetabular head index (AHI), acetabular angle and acetabular roof angle (ARA) were measured on anteroposterior pelvic radiographs taken before and after RAO. The relationship between equivalent stress in the hip joint and radiological measurements was analysed.

The equivalent stress in the acetabulum decreased from 4.1 MPa (2.7 to 6.5) pre-operatively to 2.8 MPa (1.8 to 3.6) post-operatively (p < 0.01). There was a moderate correlation between equivalent stress in the acetabulum and the radiological measurements: CE angle (R = –0.645, p < 0.01); AHI (R = –0.603, p < 0.01); acetabular angle (R = 0.484, p = 0.02); and ARA (R = 0.572, p < 0.01).

The equivalent stress in the acetabulum of patients with DDH decreased after RAO. Correction of the CE angle, AHI and ARA was considered to be important in reducing the mechanical stress in the hip joint.

Cite this article: Bone Joint J 2015;97-B:492–7.

Imageless navigation is useful in acetabular cup orientation during total hip arthroplasty (THA). There is a limitation of accuracy in the imageless navigation system because of the registration method, that is, to palpate bony landmarks over the skin. To improve this limitation, ultrasound-based navigation was introduced for more precise registration of bony landmarks. We evaluated the accuracy of placement of the implant, which was measured by CT in 66 patients. 22 patients underwent THA with imageless navigation, and 44 patients underwent THA with ultrasound-based navigation. The accuracy was evaluated by comparison of the navigation values obtained during surgery with the CT measured values.

For the 44 patients with ultrasound-based navigation system, the mean CIA was 39.6+4.1 degrees (mean+SD) and the CAA was 18.5+6.1 degrees with CT evaluation. Ultrasound-based navigation showed 39.0+3.2 degrees in CIA and 18.8+5.9 degrees in CAA during surgery. The mean absolute difference in cup inclination angle (CIA) between ultrasound-based navigation and CT was 2.4+2.1 degrees (range 0.1–9.2 degrees). The mean absolute difference in cup anteversion angle (CAA) between navigation and CT was 2.2+2.7 degrees (0.04–12.2 degrees). The rasp ante-torsion angle was 28.6+10.0 degrees in the ultrasound-based navigation system. The mean SAA was 28.8+9.3 degrees in CT. Strong correlation was found between the rasp ante-torsion angle and SAA (r=0.858). The mean absolute difference between the rasp ante-torsion angle and SAA was 4.3+3.6 degrees (0.2-17.2 degrees). For the 22 patients with imageless navigation system, the mean absolute difference between imageless navigation and CT in CIA, CAA, and SAA were 2.5+1.8 degrees (0.1–5.8 degrees), 5.4+3.8 degrees (0.1–17.2 degrees), and 5.2+3.0 degrees (1.1-12 degrees) respectively. The thickness of subcutaneous tissue at the pubic symphysis was correlated to the difference in CAA between the imageless navigation and CT (r=0.456).

Ultrasound-based navigation showed higher accuracy in CAA compare to imageless navigation. Moreover, ultrasound-based navigation showed almost the same accuracy of placement of the implant compare to the reported accuracy with CT-based navigation. Ultrasound-based navigation system improved the limitation of accuracy in the imageless navigation system.

Between 2003 and 2007, 99 knees in 77 patients underwent opening wedge high tibial osteotomy. We evaluated the effect of initial stable fixation combined with an artificial bone substitute on the mid- to long-term outcome after medial opening-wedge high tibial osteotomy (HTO) for medial compartmental osteoarthritis or spontaneous osteonecrosis of the knee in 78 knees in 64 patients available for review at a minimum of five years (mean age 68 years; 49 to 82). The mean follow-up was 6.5 years (5 to 10). The mean Knee Society knee score and function score improved from 49.6 (sd 11.4, 26 to 72) and 56.6 (sd 15.6, 5 to 100) before surgery to 88.1 (sd 12.5, 14 to 100) and 89.4 (sd 15.6, 5 to 100) at final follow-up (p <  0.001) respectively. There were no significant differences between patients aged ≥ 70 and < 70 years. The mean standing femorotibial angle was corrected significantly from 181.7° (sd 2.7°, 175° to 185°) pre-operatively to 169.7° (sd 2.4°, 164° to 175°) at one year’s follow-up (p < 0.001) and 169.6° (sd 3.0°, 157° to 179°) at the final follow-up (p = 0.69 vs one year).

Opening-wedge HTO using a stable plate fixation system combined with a bone substitute is a reliable procedure that provides excellent results. Although this treatment might seem challenging for older patients, our results strongly suggest that the results are equally good.

Cite this article: Bone Joint J 2014;96-B:339–44.

The efficacy of an imageless navigation system in acetabular cup orientation during total hip arthroplasty (THA) is well known. We evaluated the accuracy of placement of the cup and stem and leg extension length with the imageless navigation system.

Radiographic evaluation was performed in 69 consecutive patients (75 joints) who underwent primary THA from January 2009 to December 2010. Evaluation of the cup inclination angle (CI), cup anteversion angle (CA), leg extension length (L) and stem anteversion angle (SA) was carried out. SA was evaluated in 21 patients who underwent CT scan after surgery. The accuracy of imageless navigation system was evaluated by comparison of the navigation values obtained during surgery with the radiographic or CT measured values.

Good correlation was found between the navigation values and the radiographic or CT measured values in CI (P<0.001, r² = 0.579), CA (P<0.001, r² = 0.607), L (P<0.001, r² = 0.775), and SA (P<0.001, r² = 0.834). The mean absolute difference between navigation and radiograph or CT was 3.3 degrees (range 0.1 to 9.9 degrees) in CI, 4.6 degrees (0.1 to 11.4 degrees) in CA, 3.2mm (0.7 to 8.3) in L, and 3.6 degrees (0.1 to 10 degrees) in SA.

The results of this study demonstrated that imageless navigation shows good accuracy not only in cup implantation angle but also in leg extension length and in stem anteversion angle according to radiographic and CT evaluation. We conclude that imageless navigation is a useful tool for performing accurate surgery for THA.

ROBODOC is a well known tool for a computer assisted arthroplasty. However, the incision tends to enlarge with the system because of the restriction of range of motion. We have developed the robot system for minimally invasive arthroplasty. This report shows the accuracy of our system composed of original planning software, navigation and bone cutting robot.

We took the DICOM data of cadaver knees from computed tomography. The data were transferred to the workstation for planning. Matching points for registration and cutting planes were determined on the planning software. Cutting tool was the 6th robot which was able to recognize the locations of its apex and the cadaver knee with navigation system. We made five planes for TKA and two planes for UKA on femur. Then we made one plane on tibia. We evaluated the accuracy by measurement the location of cutting plane under navigation system and by CT data.

The registration errors of femur and tibia were less than 1.0mm about cadaver knees. The errors of cutting planes were 1.3 mm about the distal end of femur and 0.5 mm about the proximal end of tibia. The accuracies of the angles of cutting planes were 1.9 degrees and 0.8 degrees compared to the mechanical axis.

The errors of anterior and posterior plane of femur were increased compared to the distal plane. It was because the accuracy of registration were correct in axial direction but was not satisfied in rotational direction. The error was considered by the location of points which decided the rotation alignment. We will make effort to minimize the errors of registration and put it into practical use as soon as possible.

Periprosthetic bone loss is one of the major concerns in total hip arthroplasty (THA). Several studies have reported that bone mineral density (BMD) decreases after THA especially in the proximal femur. The phenomenon is explained as an adaptive remodeling response of bone tissue to a significant alteration of its stress environment. The purpose of this study was to evaluate the pattern of load transfer after stem implantation, and to compare the stress of finite element (FE) studies to BMD in the proximal femur after THA.

Forty-eight consecutive patients who received a primary cementless THA with implantation of the same femoral prosthesis (VerSys, Zimmer Inc, Warsaw, Idaho) between January 2007 to December 2007 were identified. Twenty-nine patients were excluded for administration of alendronate or alfacalcidol, and four patients were lost to follow-up or had incomplete computed tomography (CT) or dual-energy X-ray absorptiometry (DEXA) data. The remaining 15 patients formed the basis of this study. The average age of the patients at the time of THA was 64 years (range, 44 to 82 years). BMD were measured with DEXA at 1 week and 12 months after THA. Regions of interest (ROIs) were defined according to Gruen’s system (ROIs 1–7). FE models of the femur and stem were obtained from pre-and postoperative CT data by “Mechanical Finder (Research Center of Computational Mechanics Inc.)” that was a software to make FE models considering individual bone shape and density distribution. FE model of the femur consisted of approximately 600,000 elements and that of the stem consisted of 200,000 elements. The shaft was restrained and force was applied to the femoral head and directed within the coronal plane at 20° to the shaft axis. Stress distribution and strain energy density were analyzed and compared to DEXA data.

BMD maintained at 1 year after THA in ROI 3,4,5, and 6, where as BMD decreased in ROI 1,2, and 7 by 17%, 16%, and 26 %, respectively. This means that BMD decreased especially in the proximal femur at 1 year after THA. FE studies revealed that the stress and the strain energy density in ROI 3,4,5, and 6 were much higher than in ROI 1,2, and 7. It was suggested that high stress and strain energy density are contributed to maintenance of BMD in the femur at 1 year after THA.

Total Knee Arthroplasty (TKA) has been widely performed and successful clinical outcomes have been achieved for the patients with knee osteoarthritis which is generally known to cause ADL problem. Clinical and radiographic evaluations are commonly used when evaluating postoperative outcomes, among which kinetic analysis and gait analysis are considered essential to investigate the more detailed effect of the treatment. There is a controversy whether performing TKA on both knees simultaneously is appropriate in treating patients with bilateral knee osteoarthritis, in terms of the speed and effectiveness of gait recovery. In this study, we reviewed the significance of performing simultaneous bilateral TKA, by the results of preoperative and postoperative gait analysis.

Materials and Methods: Total of eight patients, all female and diagnosed of bilateral knee osteoarthritis, were treated with TKA and reviewed. Mean age was 70 years old (60–74). For prosthesis, we used Scorpio NRG PS, and ADVANCE, with cementation for all. No patella was replaced. Some had unilateral TKA, and some were treated bilaterally as needed. We examined distance factors (step length and step width), gait velocity, and gait barycentric factors (single-support phase and Ratio of center of gravity maximum values). We performed the analysis preoperatively, postoperatively at 1 month, 3 months, and 6 months. We used the floor pressure gauge (NITTA CORPORATION) and the three-dimensional motion analysis device (DITECT Co. Ltd) for the analysis.

Results: During the six-month follow-ups, six cases were unilateral TKA and two were treated bilaterally. Increase in step length was seen in the unilateral cases, and it decreased in the bilateral cases. Step width decreased in five cases, two cases showed no change, and increased in one case. Gait velocity had increased in all cases. Single-support phase was close to 1 for all the cases. Ratio of center of gravity maximum values, which indicates the movement of centroid during ambulation, the ratio went up for unilateral cases while it showed no change in the bilateral cases.

Discussion: Quantitative studies of gait analysis have reported that gait condition had improved after TKA. However, some reported that the gait impairment had remained. Unilateral TKA group showed gait restoration, whereas gait abnormality in either leg was seen in the bilateral group. Gait analysis is effective in determining whether surgeons should perform unilateral TKA or bilateral TKA to the patients with bilateral knee osteoarthritis. Among the gait analysis factors, we consider that Ratio of center of gravity maximum values shows effectively the improvement of the treated knee, gait, and the condition of contralateral knee.

We report the effects of local administration of osteogenic protein-1 on the biomechanical properties of the overstretched anterior cruciate ligament in an animal model. An injury in the anterior cruciate ligament was created in 45 rabbits. They were divided into three equal groups. In group 1, no treatment was applied, in group II, phosphate-buffered saline was applied around the injured ligament, and in group III, 12.5 μg of osteogenic protein-1 mixed with phosphate-buffered saline was applied around the injured ligament. A control group of 15 rabbits was assembled from randomly-selected injured knees from among the first three groups. Each rabbit was killed at 12 weeks.

The maximum load and stiffness of the anterior cruciate ligament was found to be significantly greater in group III than either group 1 (p = 0.002, p = 0.014) or group II (p = 0.032, p = 0.025). The tensile strength and the tangent modulus of fascicles from the ligament were also significantly greater in group III than either group I (p = 0.002, p = 0.0174) or II (p = 0.005, p = 0.022).

The application of osteogenic protein-1 enhanced the healing in the injured anterior cruciate ligament, but compared with the control group the treated ligament remained lengthened. The administration of osteogenic protein-1 may have a therapeutic role in treating the overstretched anterior cruciate ligament.

The purpose of this study was to describe a clinical evaluation of the etiological factors in osteochondritis dissecans (OCD) of the knee from radiographic and arthroscopic findings.

Twenty-two knees of 20 patients (16 male and 4 female, 16.1 years old in average at surgery) with symptomatic OCD of the femoral condyle were studied.

The medial femoral condyles were affected in 16 knees of 14 patients (medial group) and the lateral femoral condyle in 6 knees of 6 patients (lateral group). These two groups were compared using radiological location and arthroscopic findings. In radiography, the location of OCD was classified in accordance with Cahill et al. (1989). On the anteroposterior view, five zones were numbered 1 to 5 from medial to lateral. On the lateral view, three zones were labeled A,B and C from anterior to posterior.

In the medial group, the locations of OCD were 23BC(12), 2BC(1), 23ABC(1) and 23C(2); 14(88%) of 16 knees involved in non-meniscal area. In the lateral group, the locations of OCD were 45C(4), 5C(1) and 4BC(1); 5(83%) of 6 knees involved in meniscal area. In arthroscopy the medial group did not have medial meniscal tear, while the lateral group had 5 lateral meniscal lesions of 6 knees; 3 discoid meniscus (2 with tear and 1 without tear), 2 bucket-handle type tear and one no meniscal lesion.

Lateral meniscal lesions (with or without discoid) might cause OCD of the lateral femoral condyle. In the medial femoral condyle, we thought that OCD did not relate to meniscal lesions.

The purpose of this study is to describe a surgical procedure for unstable osteochondritis dissecans (OCD) of the capitellum and its results.

Between 1992 and 1997, 11 elbows of 11 patients with OCD of the capitellum were treated in our institution. The average age at surgery was 14.7 years and the ages ranged from 12 to 16 years. All patients were male baseball players affected in the throwing side. The follow-up period was from 31 to 95 months (average: 57 months). All patients underwent internal fixation using the pull out wiring method and bone graft (this procedure was established by Kondo in 1989). All lesions of OCD were not only softening or cracked but also unstable with early separation or partially detached fragment. After surgery, a long arm cast was applied for 3 weeks. After confirming bony union of OCD by X-ray, the wires were removed ranged from 15 to 21 weeks (average 17 weeks) postoperatively. Throwing activity was allowed 6 months after surgery.

At the follow-up, all patients were relieved pain and all except one returned to previous throwing levels. Radiographs showed good healing of OCD and minimum degenerative changes were found in only a few joints.

We concluded that this surgical procedure was an effective treatment for adolescent baseball players with unstable OCD of the capitellum.

Wear of UHMWPE and Clinical results of bioceramic total knee replacement have not been well reported yet. The ultra high molecular weight polyethylene surfaces of the tibial components were examined in 3 retrieved knees with non-infectious loosening, and were almost normal in appearance with only minor scratch lines 33 to 59 months after the initial arthroplasty. Bioceramic total knee arthroplasty was concluded to show satisfactory results except for the initial several cases done with rather poor surgical techniques. The wear of UHMWPE surface in ceramic knee was observed to be much less and milder than that of metal prosthesis.

Total knee arthroplasty (cementless) using Yokohama Medical Ceramic Knee was performed in 64 knees and, excluding 4 knees with the prostheses retrieved, was evaluated in 60 knees of 47 patients.

There ware 1 man (1 knee) and 31 women (44 knees) who had rheumatoid arthritis with a mean age of 56.8±11.9 years, and 2 men (2 knees) and 11 women (13 knees) with osteoarthritis with a mean age of 70.6±6.9 years. The mean follow-up duration was 48.1±9.2 months ranging from 33 to 60 months.

The maximum knee flexion was 115±24 degrees before and 104±20 degrees after arthroplasty in the rheumatoid group, and 107±40 degrees before and 101±26 degrees after arthroplasty in the osteoarthritis group.

Clinical evaluation using The Hospital for Special Surgery Knee Criteria showed 7 knees as Excellent, 34 as Good, 7 as Fair and 12 as Poor after surgery. Complications consisted of infection (1 case), tibial plateau fracture (1), avulsion fracture of the tibial tuberosity (1) and patellar dislocation (1)

Cytological analysis of material aspirated from the effusion which occasionally develops around a polyglycolic acid (PGA) osteosynthesis implant showed a predominance of inflammatory monocytes and in particular lymphocytes. In order to discover whether PGA implants are immunologically inert, density gradient-isolated peripheral blood mononuclear cells were cultured in 0.2 ml of 10% delta FCS-RPMI 1640 culture medium supplemented with 10 mg PGA. Phytohaemagglutinin (PHA) lectin, a purified protein derivate of tuberculin (PPD) antigen and culture medium alone were used as positive and negative controls. We studied lymphocyte activation kinetics on days 0, 1, 3 and 5. Major histocompatibility complex locus II antigen (MHC locus II antigen) and interleukin-2 receptor (IL-2R) expression were analysed using the avidin-biotin-peroxidase complex (ABC) method and lymphocyte DNA synthesis by using 3H-thymidine incorporation and beta-scintillation counting. Especially on culture days 0 and 1, lymphocytes and monocytes were seen by light microscopy to be attached to PGA particles. However, our results show no PGA-induced lymphocyte DNA synthesis, but PGA-induced MHC locus II antigen and IL-2R activation marker expression was seen, greater than in negative controls, but less than that seen in PPD antigen driven lymphocyte response. This suggests that PGA is an immunologically inert implant material, but it does seem to induce inflammatory mononuclear cell migration and adhesion, leading to a slight non-specific lymphocyte activation. This activation is lower than that seen in mitogen and antigen-driven lymphocyte responses.