Objective: Total hip arthroplasty for degenerative arthritis secondary to developmental dysplasia of the hip (DDH) remains a challenging task, and the difficulty of the procedure varies depending on the severity of the modified anatomy of the proximal femur and acetabulum. The most severe anatomical abnormality is a completely dislocated hip. In this study, we report the position of the femoral head in patients presenting with a completely dislocated hip.
Methods: Between 2007 and 2009, we performed 47 consecutive total hip arthroplasties for completely dislocated hips in 41 patients following DDH. Six patients had bilateral completely dislocated hips. On anteroposterior radiographs in the supine position, a line was drawn through the teardrops, and then a perpendicular line was drawn from the greater trochanter to that line. In addition, these lines and teardrops were used as the base. The vertical, horizontal, and direct distances of the proximal tip of the greater trochanter to were measured.
Results: Body height and weight correlated with the horizontal distance (r = 0.33, p = 0.033; r = 0.38, p = 0.013, respectively). However, no significant correlation was observed between the vertical and direct distances and the subject's height and weight. There were significant differences in the vertical and direct distances between patients with bilateral completely dislocated hips and patients with lateral completely dislocated hips (p = 0.044, p = 0.037, respectively).
Conclusion: Total hip arthroplasty for a completely dislocated hip following DDH has some surgical pitfalls. One of the most important problems concerns the subtrochanteric osteotomy. There is currently no methodology for definitively determining the final limb length and the amount of bone that should be resected. In addition, no data are presently available regarding the position of the femoral head in completely dislocated hips. This is the first report about the femur position in completely dislocated hips. A large and detailed series elucidating the position of the femoral head is therefore needed to confirm the safety and efficacy of the surgery performed on these patients.

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Objective: We compared intraoperative joint stability between the direct anterior approach (DAA) and the posterolateral approach (PLA) in total hip arthroplasty (THA).
Methods: In 59 patients undergoing primary THA (DAA group: 23 patients, PLA group: 36 patients), intraoperative posterior stability was evaluated by measuring the maximum range of internal rotation (IR) with or without subluxation in various positions of flexion and adduction. Anterior stability also was evaluated by measuring the range of external rotation (ER) in flexion 0° and adduction 0°. The ratio of subluxation in each position was calculated.
Results: The posterior stability was evaluated, and in flexion 45° and adduction 0°, the range of IR was 71.1°±12.1° (average±SD) in the DAA group and 70.1°±9.5° in the PLA group. In flexion 90° and adduction 0°, the range of IR was 55.5°±7.5° in the DAA group and 52.9°±12.3° in the PLA group. In flexion 90° and adduction 20°, the range of IR in the DAA group (47.0°±9.6°) was lower than that in the PLA group (41.1°±12.7°), although the difference was not statistically significant. The ratio of subluxation was significantly lower in the DAA group than in the PLA group in each position. The anterior stability was also evaluated, and the range of ER in the DAA group (45.7°±9.0°) was significantly greater than that in the PLA group (34.8°±7.8°); the ratio of subluxation was also significantly greater in the DAA group.
Conclusion: We compared intraoperative joint stability between the DAA group and PLA group in patients undergoing THA. DAA was suggested to be useful for improving posterior stability. Further studies on the level of anterior stability in both approaches are needed.

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Objective: Although hydroxyapatite (HA)-coated implants are widely used for cementless total hip arthroplasty, there is controversy about the use of HA coating on the acetabular component. We reviewed our cases and compared those in which HA-coated cups were used with those in which uncoated cups were used.
Methods: We retrospectively compared the radiographical results of cementless hemispherical acetabular components made of titanium (Ti) alloy with three types of surface finish: (1) uncoated (49 hips), (2) HA coated (58 hips), and (3) HA and tricalcium phosphate (TCP) coated (94 hips). Uncoated and HA-coated cups had the same rough surface (except for the HA coating) of arc-deposited commercially pure (CP) Ti. HATCP-coated cups had a CP Ti fiber-metal surface. Conventional or highly cross-linked polyethylene liners and CoCr heads were used. The stability of the cup, osteolysis, and bony apposition to the cup were evaluated by plain radiographs and computed tomographic images.
Results: After follow-up of 5-15 (mean, 8.4) years, all the cups were in situ except for two uncoated cups revised because of dislocation and osteolysis. Biological fixation was significantly different among the three groups (chi-squared test). Bony stable fixation was achieved in 100% of HA-coated and HATCP-coated cups, while 90% of uncoated cups were bony stable (including the two revised cups), but 10% were fibrous stable. Focal bone apposition at zone 3 (“acetabular spot welds”) was seen more frequently on HA- and HATCP-coated cups than on uncoated cups. Periacetabular osteolysis was detected around the coated cups as well as around uncoated cups, but was not detected in cases in which highly cross-linked polyethylene was used.
Conclusion: HA-coated and HATCP-coated cups showed similar excellent radiographical results. Sealing effects of HA coating against osteolysis were not apparent. Although both the coated and uncoated cups showed satisfactory durability, comparison between HA-coated and uncoated cups suggested that the HA coating for acetabular components had favorable effects on osseointegration, reducing the slight risk of fibrous fixation.

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Objective: Patients with hip or knee osteoarthritis suffer from severe joint pain and have a decreased activity of daily living (ADL), but they usually do not apply for certification as physically disabled under the present circumstances in Japan. In addition, even if they apply for certification, they are unable to obtain sufficient support from the government because they are certificated as seventh (or sixth for bilateral hip or knee) physically disabled grade in many cases, which indicates a relatively low level of disability. In contrast, patients who undergo total hip or knee arthroplasty are certificated as fourth (or third) grade unconditionally, i.e., they are considered to have suffered complete loss of the use of one hip or knee, despite the fact that their pain and ADL are both improved after the treatment. We think that this certification is inappropriate, and herein make a suggestion for changing the Act on Welfare of Physically Disabled Persons. A before-after study design was developed and applied to patients who were treated with total hip or knee arthroplasty for osteoarthritis.
Methods: The clinical results of patients and the physically disabled grade system according to the Act were analyzed. Patients who were treated with primary total hip or knee arthroplasty for osteoarthritis were evaluated between April 2008 and March 2011 at Sanraku Hospital, Tokyo, Japan. A total of 31 hips in 28 patients [aged 67.0±8.3 years (mean±SD)] were treated with total hip arthroplasty (THA), and 31 knees in 27 patients (aged 74.0±6.8 years) were treated with total knee arthroplasty (TKA). The Japanese Orthopaedic Association hip and knee rating scores (JOA scores) were used to evaluate the joints when the patients entered and left the hospital. Patients were also asked about their pre- and postoperative certification grades as physically disabled. The physically disabled are supported by the Act, the Order for Enforcement of the Act, and the Ordinance for Enforcement of the Act. An Appended Table in the Act defines the scope of physically disabled patients who can receive certification. Appended Table no. 5 in the Ordinance contains the physically disabled grades and states how grades are assigned. The Ministry of Health, Labour and Welfare has produced several Notices about concrete definitions and certification. These Tables and Notices were examined for orthopedic disabilities of the hip and knee, including joint arthroplasty.
Results: Preoperatively, only 1 THA patient (3.6%) was certificated as having a third grade disability; postoperatively, 24 patients (85.7%) were certified as third (6 patients) or fourth (18) grade disabled. Therefore, 23 patients (82.1%) were newly certified postoperatively. The mean total JOA score of the affected 25 hips in the certified patients made a dramatic improvement from 52.1±11.6 (/100) to 81.5±7.5 (p < 0.01), and the means of all subscales also improved. Their certified grades were third or fourth level, even though their postoperative corresponding grades were sixth or seventh level (i.e., grades based only on clinical results, without reference to certification grades and total joint arthroplasty). None of the TKA patients was certificated preoperatively, but 20 patients (74.1%) were certified as third (11 patients) or fourth (9) grade disabled postoperatively. All of these 20 patients were newly certified postoperatively. The mean total JOA score of the 23 affected knees of the certified patients made a dramatic improvement from 58.9±11.1 (/100) to 74.6±9.4 (p < 0.001), and the means of all subscales also improved. The patients' certified grades were third or fourth, even though their postoperative corresponding grades were sixth or not applicable, similar to the THA patients. ...

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Objective: The purpose of this study was to compare the clinical outcomes of one-stage revision and two-stage revision for treatment of infected total hip arthroplasty (THA).
Methods: Fifteen patients with infected THA were treated in our hospital between 2005 and 2010. Six patients were treated with one-stage revision and nine patients with two-stage revision. We compared the duration of hospitalization, operative times, estimated blood loss, recurrence rate of infection, and complications for the two procedures.
Results: The one-stage group had a significantly shorter hospitalization period and operative time than the two-stage group. There were no significant differences in the other parameters. Recurrence of infection occurred in only one case in the two-stage group. With respect to complications, the two-stage group had three dislocations of cement spacer and one patient had dissociation of cement spacer. Dislocation of the femoral head, which is a major complication, occurred in one patient in the one-stage group and in two patients in the two-stage group.
Conclusion: We concluded that the clinical results of one-stage revision for infected THA were similar to those of two-stage revision. One-stage revision is therefore effective as a treatment of infected THA, as is the two-stage procedure.

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Objectives: Tibial bone defects are frequently encountered during total knee arthroplasty. There are several methods for treating the defects, such as cement filling, bone grafts, metal wedges, and extended stem fixation, from which we choose the most appropriate one depending on the defect type. The purpose of this study was to retrospectively review our techniques for treating peripheral defects in the proximal tibia.
Methods: We reviewed 15 knees with large tibial bone defects in 14 patients who underwent total knee arthroplasty; we measured the depth and width of the defect on preoperative anteroposterior roentgenograms. The defect depth was classified as moderate (20-29 mm) or severe (over 30 mm).
Results: The depth of the defect was moderate in 11 knees, and severe in 4 knees. The average depth was 26.2 mm and the average width was 34.4% (25.9% for moderate defects, 57.7% for severe defects). In the moderate defect group, we used cement filling alone in 5 knees, increased bone resection in 3 knees, the metal wedge alone in 1 knee, the extended stem alone in 1 knee, and a combination of the metal wedge and the extended stem in 1 knee. For the severe group, we used the extended stem in all cases.
Conclusion: For moderate defects, we need to consider the depth and the width to decide whether to use the metal wedge alone or with the extended stem. For severe defects, it is required to perform a combination of the metal wedge and the extended stem.

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Objective: One of the concerns of patients undergoing total knee arthroplasty (TKA) is whether they can continue with agricultural or sporting activities after surgery; however, few studies have been published assessing these activities after TKA. In the current study, agricultural and sport participation were analyzed using a self-administered questionnaire in 100 patients who had undergone TKA.
Patients and Methods: A total of 100 patients were enrolled in this study, comprising 92 women and 8 men with a mean age of 73.4 years (range, 56-86 years) with a mean follow-up of 5.2 years (range 1-17 years). Eighty-five patients were diagnosed with osteoarthritis and 15 patients were diagnosed with rheumatoid arthritis. All 100 patients were given a self-administered questionnaire about their agricultural and sporting activities after TKA was performed.
Results: Fifty-one patients engaged in agricultural activities before surgery, and 44 of 51 patients continued these after TKA. The return to agriculture rate was 86.2%: 34 patients returned to work in truck farms, 18 patients continued as fruit farmers, and 9 patients continued with rice cultivation. Before knee disturbance, 30 of 100 patients participated in some sports, and 15 of 30 patients returned to sport after TKA. The return to sport rate was 50% in our series.
Conclusion: Of the patients who engaged in the relevant activity before TKA, 86.2% continued agricultural activities and 50% returned to participate in sporting activities after TKA in the current study. These data indicate that the clinical results of TKA are not adversely affected by lower-impact activities. However, we recognized that further study is necessary regarding agricultural and sporting activities after TKA.

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Objective: This study was designed to clarify the effects of intra-articular high-molecular-weight hyaluronic acid injections (Suvenyl) and nonsteroidal anti-inflammatory drugs (NSAIDs) in patients with early-stage osteoarthritis (OA) of the knee using the Japanese knee osteoarthritis measure (JKOM).
Methods: In total, 139 patients (38 men and 101 women, aged 59.9±10.5 years) with early-stage OA of the knee (Kellgren-Lawrence criteria less than grade II) were enrolled in this study. All patients were randomly allocated to either the Suvenyl group (85 patients, 24 men and 61 women) or the NSAID group (54 patients, 14 men and 40 women). The JKOM and the visual analogue scale (VAS) as a pain index were investigated in both groups from before intervention to 6 weeks after intervention.
Results: The patients' characteristics (age and sex) were not significantly different between the two groups. The VAS score showed significant improvement in 6 weeks compared with the baseline in both groups (43.5 to 23.3 mm in the Suvenyl group and 42.2 to 22.1 mm in the NSAID group, p < 0.01, respectively). The JKOM score significantly improved in 6 weeks compared with the baseline in both groups (27.3 to 19.7 points in the Suvenyl group and 27.2 to 16.1 points in the NSAID group, p < 0.05, respectively). However, there were no significant differences in the VAS and JKOM scores between Suvenyl and NSAID groups.
Conclusions: These results suggest that intra-articular high-molecular-weight hyaluronic acid injections may be an effective treatment for patients with early stage OA of the knee; the results demonstrated no differences in effectiveness between the two treatments.

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We report on a patient who underwent repeated total knee arthroplasty (TKA) due to an infection that persisted for more than 8 years. A 69-year-old man with rheumatoid arthritis diagnosed in 1987 underwent TKA of the left knee in July 1998. The implant gradually loosened over the following year with possible infection. In March 2000, one-stage TKA was performed again using bone cement containing vancomycin. Purulent discharge occurred 2 weeks after the second TKA. After a more than 8-year course of persistent chronic osteomyelitis, the implant was removed (Neisseria elongata subspecies nitroreducens was isolated by intraoperative culture) and replaced with cement beads containing gentamicin on March 11, 2009. A third TKA and allogeneic bone transplantation were performed 10 weeks later. At 1 year and 7 months after the third TKA, no relapse of infection or loosening of the artificial joint has occurred. Suppression of the infection was possible because the causative bacterium was not antibiotic resistant, the affected area was completely curetted, the third TKA was performed at an appropriate interval after the second TKA, all cultures became negative before the third TKA, and the wound was completely closed to assure that dissolution of the antibiotic from the cement beads would be confined to the affected area.

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Many causes of painful knee following total knee arthroplasty (TKA) have been reported. We report a case of posterolateral pain occurring after TKA that was successfully treated by resecting the popliteus tendon. A 63-year-old woman with right knee osteoarthritis underwent TKA in July 2009. The angle of the lift-off between the femoral and tibial components was 0° Seven months after the first operation, the patient's range of motion was limited to 15°-100°, and pain developed in the lateral posterior part of the knee with matching tenderness in the right popliteus tendon. Since impingement between the popliteus tendon and the posterior condyle of the femoral component was assumed and articular contracture was present, joint mobilization and the resection of the popliteus tendon compressed from the outer edge of the posterior condyle of the femoral component were performed at 9 months after the first operation. Two months after the final surgery, the posterolateral pain had disappeared and the patient's range of movement had improved to 5°-125°. No differences between the knees were observed using a dial test. From the epicondylar view, the angle of lift-off remained the same at 0°. In this case, impingement of the posterior condyle of the femoral component and the popliteus tendon after TKA caused posterolateral pain that was successfully treated by resecting the popliteus tendon. Postoperatively, varus instability, changes in the lift-off angle, and bilateral differences in the dial test results were not observed, and therefore lateral and posterolateral instability were assumed not to have occurred. To prevent the postoperative impingement of the popliteus tendon in such cases, additional popliteus tendon resection should be considered in cases of impingement occurring during primary TKA.

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