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We present a case of solitary chondrosarcoma arising from the proximal phalanx of the ring finger in an elderly man. The chondrosarcoma developed over a period of 14 years, during which the phalanx became progressively more deformed. Several radiographic investigations were carried out, but the patient declined further suggested diagnostic examinations (computed tomography, magnetic resonance imaging, biopsy). Eventually, the lesion became significantly enlarged, and radiographs showed osteolytic lesions in the phalangeal bone. Ray amputation of the finger was required to establish a wide resection of the chondrosarcoma. Most osteochondral tumors arising from the phalanges are benign tumors such as enchondromas, but primary chondrogenic malignant bone tumors (chondrosarcomas) occasionally occur. Chondrosarcoma of the phalanx is difficult to distinguish from enchondroma of the phalanx, because histological investigations of the two neoplasms often produce similar findings. Even with a combination of clinical, biopsy, and imaging findings, differentiating these neoplasms is still challenging, because the characteristic clinical and radiological features of chondrosarcoma do not appear until it becomes aggressive and starts to cause destructive changes. Once that happens, radical expanded resection of the tumor is essential. Therefore, longstanding enchondroma-like lesions should be actively treated in elderly patients, even if a definite diagnosis of chondrosarcoma cannot be made.

Lumbar disc herniation (LDH) is a frequently encountered pathologic condition in orthopedic daily practice. Discectomy is considered when patients with LDH experience persistent limb or lumbar pain or neurologic deficits. Various minimally invasive techniques are available for discectomy. Among these techniques, full-endoscopic lumbar discectomy (FED) is one of the least invasive options. During FED, removal of LDH is accomplished using 2 major approaches: transforaminal (TF) or interlaminar (IL). The prototype FED was percutaneous nucelotomy. An endoscope was integrated to percutaneous nucelotomy and TF endoscopic lumbar discectomy (TELD) was first derived. IL endoscopic lumbar discectomy (IELD) was introduced years after TELD. TELD and IELD can compensate for the shortcomings of each other and endoscopic spine surgeons need to acquire both techniques to deal with all type of LDHs. Because of its long history, the TF approach seems to represent the major approach for FED, but the IL approach has numerous benefits in particular types of LDH. The present article focuses on IELD and reviews the history, surgical techniques, indications and contraindications, clinical outcomes, and complications. This review will contribute to improved understanding of IELD as an important technique in full-endoscopic spine surgery.

Management of transcondylar fracture of the humerus in older adults remains a challenging issue in trauma surgery. Both single- and double-plate fixation are used, and the best procedure is yet to be determined. This retrospective study evaluated and compared the clinical and radiological outcomes of single- and double-plate fixation for transcondylar humeral fracture.This study included older adults (age65 years) with transcondylar fractures of the humerus (AO/OTA 13A2-3; transverse, transmetaphyseal fracture) treated at our hospital between 2002 and 2019. The patients were divided into two groups based on the fixation procedures they underwent, namely, single (group S) or double (group D) locking plate osteosynthesis. Postoperative outcomes were investigated.Group S and group D comprised 11 (11 women) and 17 (2 men; 15 women) patients, respectively. In group S, the elbow was immobilized in a long-arm cast or splints for 2 weeks to prevent early displacement of fracture. Residual numbness of the ulnar digits was observed in two patients in group S and in nine patients in group D. No significant difference was noted between the two groups in the ratio of loss of reduction, loosening of the medial screw, ulnar nerve disturbance, or clinical outcomes. The ratio of elbow contracture significantly differed between 2 groups. The elbow flexion angle was significantly lower in group S.Open reduction and internal fixation with a double plate appears to be the optimal choice for early postoperative mobilization and maintenance of flexion and arc of the elbow joint.

Introduction: Osteoporotic vertebral compression fractures (OVCFs) are common fractures in the elderly suffering osteoporosis. Most patients have bone fusion with deformity of vertebral collapse; however, some patients suffer nonunion and persistent pain at the fracture site. Due to the limitations of conservative treatment, balloon kyphoplasty (BKP) has been recently performed for OVCFs. This study aimed to investigate the relationship between cement embolization and balloon expansion pressure (BEP) in patients who underwent BKP. Methods: We investigated 62 patients who underwent BKP for cement embolization into the perivertebral veins among the 155 patients admitted to our hospital due to thoracolumbar vertebral compression fractures between April 1, 2019, and March 31, 2020. Surgery was indicated for patients who had severe back or low back pain and whose daily life was severely impaired, and in whom the shape of the vertebral body was clearly changed on functional X-ray. Results: Intraoperative X-ray and postoperative CT revealed cement embolization into the perivertebral veins in three cases (4.83%). The BEP was significantly higher in the group with cement embolism than in the group without cement embolism (P < 0.001). Pulmonary cement embolism (PCE) and infection were not observed. One case of cement leakage into the spinal canal was observed (1.61%). Conclusions: While the surgical intervention of BKP can contribute to the treatment of OVCFs, careful attention should be paid to the prevention of complications, including cement embolization into the perivertebral veins, and such complications should be appropriately managed.

Venous thromboembolism (VTE) is one of the most important complications in orthopedic surgery. Deep-vein thrombosis occurs frequently after surgery with few clinical symptoms. Formed emboli are thought to cause pulmonary thromboembolism (PTE). It is well known that PTE has a high-mortality rate when it develops. The cost of medical care is doubled when VTE develops after surgery. As a result, it is imperative to focus on the prevention of VTEs following major orthopedic surgeries.The prevention method should be selected in consideration of the balance between the VTE and bleeding risks owing to drug prophylaxis. It is recommended that we choose either physical or drug prophylaxis, or both. To perform VTE prophylaxis, we need to explain the risks and merits of prophylaxis and ensure that these are understood by patients.

BACKGROUND This study sought to assess the efficacy of a deep-tissue thermal therapy system with a resonant cavity applicator (DTT-RCA), which safely heats deep joint tissue for treating osteoarthritis (OA) of the knee. METHODS Two groups of participants were recruited. The DTT-RCA group comprised 20 knees. Kellgren-Lawrence (K-L) grade was I and II in 8 knees (DTT-RCA I/II group) [mean age 73.3 years (standard deviation 11.4) ], III and VI in 12 knees (DTT-RCA III/IV group) [75.4 (8.6) years]. The control group comprised 13 knees [68.2 (10.8) years]. K-L grade was I in 7 knees and II in 6 knees. This group received exercise therapy. The DTT-RCA I/II group and the control group were imaged by MRI T2 mapping at baseline and 6 months to determine the area of cartilage degeneration. RESULTS Visual Analogue Scale improved only in the DTT-RCA I/II post-intervention (p < 0.01). Japanese Orthopedic Association knee rating scores (DTT-RCA I/II: p < 0.01, control group: p < 0.01), the Japanese Knee Osteoarthritis Measure (DTT-RCA I/II: p < 0.05, control: p < 0.01), and the Knee injury and Osteoarthritis Outcome Score (DTT-RCA I/II: p < 0.01, DTT-RCA III/IV: p < 0.05, control: p < 0.01) post-intervention. The magnitude of change did not differ significantly between the three groups. The area of cartilage degeneration did not change significantly post-intervention in the DTT-RCA I/II group, not even relative to the control group. CONCLUSIONS This was the first study to test a DTT-RCA system in patients with knee OA. The system reduced the clinical symptoms of knee OA and could potentially be effective for conservative therapy.

A 28-year-old woman developed gait disturbance due to lower limb weakness 3 years before presentation. Conventional magnetic resonance imaging (MRI) findings were inconclusive; therefore, we performed cine MRI, which confirmed the presence of a pulsatile cyst on the posterior thoracic spinal cord. The cyst compressed the spinal cord, and its pulsations synchronized with the patient's heartbeats. We resected the intradural arachnoid cyst and thickened arachnoid membrane. The gait disturbance improved after surgery.Cine MRI can be used to identify a pulsating arachnoid cyst that cannot be visualized with a conventional MRI. Cine MRI is useful in patients with unexplained spinal symptoms.

Ganglion cysts are common benign lesions in the hand and wrist. However, intratendinous ganglion cysts are uncommon. We present a case of intratendinous ganglion cyst in the extensor pollicis longus (EPL) tendon of the right hand of a 73-year-old woman. The subcutaneous mass moved in concert with the EPL tendon in her right thumb. Magnetic resonance imaging showed a space-occupying lesion in the EPL tendon. Biochemical and hemato-immunological examinations ruled out diabetes, rheumatoid arthritis, and other connective tissue diseases. She reported motion pain during thumb extension, for which she desired surgery. An intratendinous cyst was identified intraoperatively within the tendon substance of the EPL, in which a part of the cyst was herniated into a slit in the tendon substance, just distal to the extensor retinaculum, without notable proliferative synovial tissue. The EPL tendon was opened longitudinally, and a cystic lesion was enucleated. Pathological examination showed that the cyst wall consisted of fibrous tissue with degeneration and no epithelial lining. Postoperative recovery was uneventful. Six months after surgery, the patient had no residual pain and no cyst recurrence. The rarity of intratendinous ganglion cysts makes diagnosis and treatment challenging. Because intratendinous ganglion cysts and associated synovitis frequently weaken the structure of affected tendons, prompt diagnosis and surgical excision are necessary.

Posttraumatic malunion of the phalanx with rotational deformity may cause crossing of the finger and impair hand function. Cosmetic disfigurement and severe dysfunction of the fingers require surgical correction, most often via open corrective osteotomies and rigid fixation with plates. However, such an approach requires a longer incision, inevitably results in a scar, and has a higher potential for extensor tendon adhesions, which result in extension lags. In addition, abruption of the periosteum and plating of the phalanges require longer bone healing. This report describes the straightforward, minimally invasive correction of phalangeal malunions with a mini-external fixator. In this procedure, a digital block of the affected finger can be performed. The fully flexed position of all fingers provides accurate correction of phalangeal malunions. Although treatment of phalangeal malunions remains challenging, the present procedure is an alternative solution for phalangeal malunions.

Background To restore neutral limb alignment in total knee arthroplasty (TKA), the procedure usually starts with removing osteophytes in varus osteoarthritic knees. However, the exact effect on alignment correction is unknown. The purpose of this study was to determine the effect of osteophyte removal alone during TKA for varus knees on correction of limb alignment on the coronal plane. Methods Fifteen knees with medial osteoarthritis and varus malalignment scheduled for TKA were studied. After registration in a navigation system, each knee was tested at maximum extension, and at 30, 40, and 60 degrees of flexion, before and after osteophyte removal. External loads of 10 N·m valgus torque at each angle and in both states were applied. Later, the widths of the resected osteophytes were measured. Results The average preoperative hip-knee-ankle angle was -14.2 degrees. The average width of osteophytes was 7.6 mm in the femur and 5.3 mm in the tibia. Angle corrections after osteophyte removal were 3.4 degrees at maximum extension, 3.4 degrees at 30 degrees flexion, and 3.6 degrees at 60 degrees flexion; the difference was significant for all angles. There was a positive correlation between osteophyte width and the degree of angle correction at 30 degrees. Conclusion At 30 degrees of knee flexion, osteophyte width was correlated with the degree of angle correction on the coronal plane in TKA. The degree of angle correction per 1 mm of width of removed osteophytes was 0.4 degrees.

The pedicle sign is a radiographic indicator of spinal metastases. However, it is not only the pedicle sign that is important in radiographic diagnosis of bone metastases. In the present study, the radiological features of symptomatic spinal metastases in patients without the pedicle sign were retrospectively examined.Among 186 patients with symptomatic spinal metastases who visited our department between January 1, 2011, and December 31, 2017, 64 without the pedicle sign and with available computed tomography (CT) and magnetic resonance imaging (MRI) data in the first visit were enrolled and their data were analyzed. One author evaluated radiographs for findings suggestive of spinal metastases, CT to assess bone destruction, and MRI to evaluate the extent of lesions. Clinical variables were also examined and compared between patients with and without bone changes on radiography.Bone changes strongly suggesting bone metastasis, other than the pedicle sign, were observed in 31 out of 64 patients: bone cortical disappearance in 20, increased radiolucency of the central area in the vertebral body in 8, an irregular osteoblastic change in 5, and asymmetrical vertebral collapse in 10. An analysis of CT data revealed that intertrabecular, mildly osteolytic, and mildly osteoblastic types were more frequent in patients without any changes suggestive of bone metastases on radiographs.Radiographic findings other than the pedicle sign are useful for diagnosing bone metastases. The key to a radiographic diagnosis of spinal metastases is to pay attention to changes in the bone cortex of all vertebral components on radiographs in addition to the pedicle.

BACKGROUND The purpose of this study is to evaluate the clinical outcomes of the elderly with coronal shear fractures (CSFs) of the distal humerus who had undergone open reduction and internal fixation (ORIF). METHODS Between April 2002 and March 2019, eight elderly patients (76.3 ± 5.1 years)with CSFs of the distal humerus were investigated retrospectively. Postoperative complications, the range of motion (ROM) of the elbow joint, and functional elbow scoring (Mayo elbow performance score; MEPS) were assessed. RESULTS The mean follow-up duration was 23.6 ± 13.9 months. CSFs were treated by a buried implantable headless screw or Kirshner wires or bioresorbable screw with/without lateral locking plates. There were no superficial or deep infections, or elbow joint instability. Seven patients obtained fracture healing, but one patient showed non-union. Osteochondritis dissecans was present in one patient. Three patients showed step-off deformity (> 2 mm) of the articular surface. Two patients displayed a collapse of the fractured articular surface. A patient with severe comminution of both the capitellum and the trochlear showed the collapse of the whole articular surface with osteonecrosis of the capitellum and trochlea. Mean the range of motion of the elbow were flexion, 116.3±12.7° and extension, -28.8±14.1°. The mean MEPS was 78.8±10.2 points, representing patients who scored an excellent (n=1), good (n=3), and fair (n=4). CONCLUSION ORIF yielded satisfactory outcomes for theelderly with noncomminuted CSF of the distal humerus. However, the cases with comminuted articular fragment or complex posterior fractures were still challenging.

Knees with severe varus osteoarthritis can develop medial structure contracture. However, there is no report on the relationship between severity of varus deformity and contracture of the medial structure. We aimed to determine the threshold angle that could be corrected in proportion to the width of medial osteophyte removal and to examine correction differences between angles larger and smaller than the threshold angle in total knee arthroplasty.This study included 27 varus osteoarthritic knees scheduled for total knee arthroplasty (TKA). A navigation system was used to measure hip-knee-ankle angle (HKA) in all knees at maximum extension and 30˚ and 60˚ flexion, before and after osteophyte removal and with and without external 10 N-m valgus torque loads. Subsequently, resected osteophyte widths were measured. Mean correction angle per 1 mm of osteophyte removal was calculated, and the threshold angle was calculated with the receiver operating characteristic curve. HKA differences were compared against deformities larger and smaller than the threshold angle.Mean osteophyte width was 7.1±2.20 mm. Osteophyte removal produced a mean 3.1° correction, which equaled a 0.4° correction per 1 mm of osteophyte width removal. The varus deformity threshold angle was 9.5°. However, when comparing groups with angles larger and smaller than the threshold angle, there was no significant difference in HKA difference between each step and flexion angle.The threshold angle for expected correction with medial osteophyte removal was 9.5˚. However, because there were no differences in correction between those with angles larger or smaller than this, medial structure contracture seemed to be unrelated to the severity of deformity.

Background The direct superior approach (DSA), which is one of the muscle-sparing approaches for total hip arthroplasty (THA), has been recently reported with positive outcomes. However, in minimally invasive THA, it has been reported that the visual intraoperative estimation of the cup position is not reliable. Therefore, those minimally invasive approaches are associated with the increased risk of acetabular cup malposition due to the limited exposure. Although the positive effects of computer navigation system on the accuracy of cup positioning have been reported in many studies, those are not unknown in THA via the DSA. In the current study, we investigated the accuracy of acetabular cup positioning in navigated THA via the DSA in the first 30 consecutive cases.Methods We have retroactively included the first 30 consecutive cases of navigated DSA, and the consecutive control cases using conventional posterior approach (PA) were included retroactively up to 30 cases. This retrospective study divided the cases of navigated DSA into 15 initial and 15 recent cases. The postoperative data were assessed on plain computed tomography to measure the radiographic inclination and anteversion of the acetabular component. Statistical analyses were performed using Mann-Whiteney U test for comparison of the mean, and Levene's tests for equality of standard deviations (SD). Results We found no significant differences in the means between navigated DSA and conventional PA for anteversion and inclination. For anteversion, the accuracy of acetabular cup positioning in navigated DSA (SD, 6.9°), including the recent 15 cases (SD, 4.1°), was significantly improved than in conventional PA (SD, 11.7°). For inclination, there were no significant differences in the accuracy of the acetabular cup positioning between navigated DSA (SD, 5.3°) and conventional PA (SD, 6.5°).Conclusions The increased variances of cup anteversion would be due to the frequency of pelvic malposition and the wide variation in pelvic orientation with the patient in the lateral decubitus position. Navigated THA via the DSA could be performed with good accuracy of cup placement in the first 30 cases. The results suggest that computer navigated THA via the DSA as a suitable option for hip replacement.

Background: Rotator cuff tear with delamination is considered as a risk factor for postoperative retear after rotator cuff repair. The purpose of this study was to compare clinical outcomes between 3 repair procedures for large or massive rotator cuff tears with delamination: conventional en masse suture bridge (EMSB), double-layer suture bridge (DLSB), and combination of double-layer suture bridge and modified Debyere-Patte (DLSB+DP) methods.Methods: A total of 53 shoulders of 52 patients who had large or massive rotator cuff tears with delamination were included. The patients were categorized into 3 groups: EMSB group comprised 18 patients, DLSB group comprised 24 shoulders of 23 patients, and DLSB+DP group comprised 11 patients. DP was applied for cases in which the rotator cuff was unable to be covered up to the footprint even though it was sufficiently mobilized. The mean postoperative follow-up period was 34.6 months (range, 24-72 months). Pre- and postoperative evaluations included the Constant scores and range of motion (ROM). Tendon integrity according to Sugaya classification, and fatty degeneration were also evaluated by magnetic resonance images (MRI).Results: The ROM significantly improved after the operation in all groups. Mean constant scores significantly improved (from 45.5±14.3 to 77.4±13.6, in the EMSB, from 45.5±11.6 to 87.6±11.4 in the DLSB, and from 46.3±11.2 to , and 88.0±10.5 in the DLSB+DP). Significant differences were noted in the postoperative Constant score (pConclusions: Comparison of 3 groups demonstrated that DLSB and DLSB+DP achieved better clinical outcome than EMSB. DLSB+DP is useful for large or massive rotator cuff tears with severe fatty degeneration or for cases where presence of excessive tension is anticipated when repairing the torn cuff.

BACKGROUND Methotrexate (MTX) is still the first-choice drug for the treatment of rheumatoid arthritis (RA). In Japan, MTX doses of up to 16 mg/week were approved in 2011. In this study, we aimed to identify the gene polymorphisms that can predict therapeutic effects of MTX in Japanese patients in current clinical settings. METHODS This study involved 171 patients with RA (all Japanese nationals, age 63.5±10.0 years) who had been administered MTX. The analyzed polymorphisms included 82 single nucleotide polymorphisms (SNPs) involved in the MTX pharmacological pathway or in the pathogenesis of RA. Responders were patients who showed high sustained remission or low disease activity with MTX or conventional disease-modifying anti-rheumatic drugs (DMARDs) treatment beyond 6 months. Non-responders were patients who showed moderate or high disease activity, who were prescribed biological DMARDs. A logistic model was constructed with Responder/Non-responder as the target variable, and minor allele frequency was set as an explanatory variable. RESULTS None of the 82 SNPs targeted for analysis met the Bonferroni significance threshold of 6.098×10-4. However, we identified SLCO1B1 rs11045879 as an SNP that might yield significant results if the number of patients were to be increased (P=0.015). CONCLUSIONS The rs11045879 minor allele in the SLCO1B1 gene is a potential predictor of non-responders to MTX treatment among Japanese RA patients. In future collaborative research, we will investigate whether the association with SLCO1B1 polymorphism is significant by performing statistical analysis with a larger study population.

Background Hip endoprosthesis is one option for the treatment of displaced femoral neck fractures and avascular necrosis of the femoral head. Few reports are available describing acetabular cartilage metabolism after endoprosthesis surgery of the hip. The purpose of this study was to compare the biological effects on cartilage between cobalt-chrome (Co-Cr) and alumina ceramic heads wherein the cartilage articulates directly. Methods We used the acetabular cartilage from six hips of three immature crossbred pigs to examine the effects on cytokines, the amount of hyaluronic acid (HA), and cartilage mRNA expression of ceramic head and Co-Cr head endoprosthesis. Mechanical loading of materials of Co-Cr and ceramic heads was performed on the acetabular cartilage in culture media as an organ culture model. Thereafter, protein levels of cytokines (MMP-1, 3, TNF-alpha (α), Interleukin (IL)-1 alpha (α), and IL-1 beta (β)) and the amount of HA were measured from the culture media. Cartilage RNA extraction was performed, and quantitative reverse transcriptase-polymerase chain reaction was performed with primer sets for type I, II, and III collagens; aggrecan; MMP-1, 3, 13; TNF-α; and IL-1 α, IL-1 β. Results Protein level of IL-1 β and amount of HA in the Co-Cr group were significantly higher than those of the Ceramic group. Type II collagen mRNA expression in the Ceramic group was significantly higher than in the Co-Cr group. IL-1 β mRNA expression was significantly higher in the Co-Cr group than in the Ceramic group. Conclusions The present study showed that ceramic bipolar produces smaller adverse effects on cartilage cells compared to Co-Cr bipolar. These results could have significant implications for implant usage not only in hip joints, but also in other joints, including the shoulder, talus and radial head.

Background Obtaining well-balanced soft tissues is important to achieve natural knee kinematics after total knee arthroplasty (TKA). In conventional procedures, soft tissue balance is evaluated with spacer blocks or lamina spreaders. However, the evaluation depends on the surgeons' experience and is not quantitative. This study aims to measure the mechanical properties of knee soft tissue with a new ligament balancer and to determine the optimal distraction force for evaluating tibiofemoral joint gaps in TKA. Methods This study included 30 consecutive patients with medial knee osteoarthritis who were scheduled to undergo posterior stabilized TKA. The mean age of patients was 73 ± 9.6 years at the time of surgery, and the mean hip-knee-ankle angle was 13.1 ± 6.5° in varus. After distal femoral and proximal tibial resections, the tibiofemoral joint gaps under several distraction forces were measured in extension and at 90° flexion. The load-displacement curves in extension and flexion were drawn with these data, and the stability range, which was defined as the shift range from the toe region to the linear region in the curves, was calculated. Results The stability ranges were 160 Newtons (N) in extension and 140 N in flexion. Conclusions These displacement forces were considered optimal for evaluating tibiofemoral joint gaps during surgery and ensuring knee stability after TKA.

Case A 49-year-old man, who had started jogging 3 months before his first participation in a marathon race, presented with acute pain and difficulty walking that began during the marathon race. Tumors and bone metabolism factors were ruled out by blood examination and various imaging findings. Isolated iliac wing fatigue fracture was diagnosed and treated with conservative therapy. Conclusion This is the first English-literature report we know of an isolated iliac wing stress fracture in a male marathon runner without underlying disease. Our study highlights the importance of considering this rare fracture when diagnosing patients presenting with iliac pain.

We report our case of ligament reconstruction for treatment of proximal tibiofibular joint disorder using a semitendinosus tendon graft. A 21-year-old male college soccer player with no remarkable history of injury had been suffering from pain at the lateral aspect of the left knee when playing soccer. At another hospital, the patient was diagnosed with a lateral meniscus injury and cartilage injury of the external condyle of the tibia and underwent partial resection of the meniscus and bone drilling. However, his symptoms continued, and he was referred to our institution. Instability of the left proximal tibiofibular joint and pain were noted during weight-bearing dorsiflexion of the ankle. We diagnosed the case as a proximal tibiofibular joint disorder and surgically treated it by dissecting the proximal portion of the semitendinosus tendon, creating one transfibular and two transtibial tunnels, and then reconstructing the proximal tibiofibular ligament using the harvested semitendinosus tendon graft. The patient was allowed to run at postoperative 2 months, with no pain occurring while squatting at postoperative 3 months, subsequently resuming soccer at postoperative 8 months. The proximal tibiofibular joint disorder is a relatively rare pathology, and diagnosis and conservative treatment are often difficult. Although various surgical treatments are known, the clinical outcome of our case has been successful after reconstructing the anterior and posterior proximal tibiofibular ligaments using a semitendinosus tendon graft.

Posterior cruciate ligament (PCL) resection during posterior-stabilized total knee arthroplasty (PS-TKA) has been reported to preferentially increase the tibiofemoral joint gap in flexion compared with extension. However, previous assessments of the joint gaps have been performed after bone resection and medial soft tissue release. Thus, these procedural steps may have the potential to influence soft tissue balance. In native knees, soft tissue laxity is generally greater in the lateral compartment than in the medial compartment both with the knee in extension and in flexion. Some surgeons may retain this natural soft tissue balance with less aggressive medial release during TKA. We performed this study to evaluate the impact of the PCL resection on the extension and flexion gaps in the absence of bone resection or medial soft tissue release. Tibiofemoral joint gaps for 41 patients (10 males and 31 females) in full extension and at 90 degrees of flexion both before and after the resections of both the anterior cruciate ligament (ACL) and PCL were assessed using a ligament tensioner device. The statistical analyze was performed using the Mann–Whitney U test. The results showed that medial gap in extension and flexion were 6.7 ± 1.0 and 7.3 ± 0.9 mm, and lateral gap in extension and flexion were 7.6 ± 1.1 and 8.4 ± 1.6 mm, respectively. Thus, physiological tibiofemoral gaps just after knee arthrotomy were trapezoidal and asymmetric shape with the significantly wider gaps in lateral and flexion, compared with the medial and extension, respectively (p

Background Total knee arthroplasty (TKA) aims to correct the rotation, as well as the alignment and articulation, of the osteoarthritic knee. We hypothesized that, in addition to improving knee kinematics, TKA affects hip rotational movement. The objective of this study was to evaluate variation in lower extremity alignment and hip rotational range of motion (ROM) after TKA. Methods A total of 47 patients (53 knees) with primary varus knee osteoarthritis who were scheduled for primary TKA at our center were enrolled. Hip rotational ROM was measured with the patient in supine position with 90° flexion of the hip and knee before and 3 weeks after TKA. Plain radiography and computed tomography were used to compare variations in tibial axis alignment and femoral axis alignment after bone resection, which was defined as changes in the joint lines of the distal femur and the proximal tibia. Results Average internal ROM, and the sum of internal and external hip rotational ROM, increased significantly; however, external hip rotational ROM did not significantly differ after TKA. Imaging findings showed that the axis of the lower leg externally rotated by 2.5°, with a 4° internal rotation of the distal femur and a 6.5° correction of the varus deformity. Conclusion TKA changed the neutral position of hip rotational movement and increased hip rotational ROM.

BACKGROUND Although unicompartmental knee arthroplasty (UKA) has become more common because of its good outcomes, several complications have been reported. Tibial implant alignment, an important cause of such complications, has been investigated; however, the optimal alignment of the tibial implant has not been determined. This study used 3-dimensional finite element analysis to investigate changes in stress distribution in the proximal tibia after UKA at multiple tibial implant alignments. METHODS A 3-dimensional finite element model was created with CT digital imaging and communications in medicine (CT-DICOM) data from a medial osteoarthritic knee. Change in stress distribution of the tibial implant alignment on the coronal plane (middle position, varus 5°, valgus 5°) and sagittal plane (0°, 5°, 10°) under conditions of a loose boundary between implant and bone and no loosening was analyzed with 3-dimensional finite analysis. RESULTS In the absence of loosening, the stress distribution was high at the lateral rim of the subchondral bone in the varus alignment model, and the high stress distribution moved from the anterior to the posterior position with posterior tilting from 0° to 10°. With loosening, the stress distribution was high at the proximal tibial medial cortex in the valgus alignment model. CONCLUSIONS To reduce UKA complications, the present findings indicate that the optimal alignment of the tibial implant is at the middle position on the coronal plane, with a posterior inclination similar to the original inclination on the sagittal plane.

Background Femoral rotational alignment is considered an essential factor for total knee arthroplasty because malrotation of femoral components results in poor outcomes. To obtain proper alignment, we developed a superimposable computed tomography (CT) scan-based template to intraoperatively determine the accurate surgical epicondylar axis (SEA), and evaluated the effectiveness of this CT template. Methods In the experimental group (n = 55), three serial slices of CT images, including medial and lateral epicondyles, were merged into a single image, and SEA was overlaid. SEA was traced onto an image of an assumed distal femoral resection level; this combined image was then printed out onto a transparent film as a CT template. Following a distal femoral resection in TKA, SEA was duplicated onto the femoral surface. Thereafter, the posterior condyle was resected parallel to this SEA. In the control group (n = 53), posterior condyles were resected at three degrees of the external rotation from the posterior condylar line (PCL). A posterior condylar angle (PCA) between PCL of the femoral component and SEA was postoperatively evaluated. Positive values indicated external rotation of the femoral component from the SEA. Results In the experimental group, PCA was 0.01° ± 1.61°, and three cases were considered as outliers (greater than three degrees or less than −3 degrees). Conversely, in the control group, PCA was 0.10° ± 2.4°, and 12 cases were considered as outliers. Consequently, dispersion of PCA data was significantly smaller in the experimental group (P = 0.004). Conclusions The CT template accurately determined intraoperative SEA.

We describe a rare case of a fracture of the medial tubercle of the posterior process of the talus in a 16-year-old male athlete who fell during basketball practice. The patient presented to our orthopedic clinic when pain and swelling had persisted despite 2 weeks of anti-inflammatory medication and rest. Computed tomography and magnetic resonance imaging scans revealed a fracture of the posteromedial tubercle of the talus and a small amount of retained fluid in the joint. Immobilization with a below-the-knee cast and non-weightbearing for 4 weeks, with a gradual return to full activity, was successful. At the 1-year follow-up evaluation, the patient expressed no complaints. Fracture of the posteromedial tubercle of the talus will usually result in a misdiagnosis or delayed diagnosis owing to the insidious onset of symptoms. We believe the present fracture configuration resulted from the vertical compression force that occurred on landing by posterior medial ankle impingement in plantarflexion-supination, modifying the conventional concept of the posteromedial tubercle fracture. We also present a suggested classification with a flowchart diagram.

Background A vitamin A derivative, 13-cis-retinoic acid (isotretinoin), has been administered to treat several types of pediatric cancer and has improved survival rates in patients despite being known to induce premature epiphyseal closure. As the number of patients treated by 13-cis-retinoic acid increases, demands for salvage treatment after systemic retinoid therapy are emerging. However, few studies have described the surgical treatment of this disease. Case presentation We report a case with bilateral varus knee deformity due to premature epiphyseal closure that occurred during treatment with isotretinoin for neuroblastoma. The patient was successfully treated with correction osteotomy using a Taylor spatial frame in the right knee joint and femoral closed wedge osteotomy using a locking plate in left knee joint. Histopathological examination of the growth plate showed polar irregularity of chondrocytes and decreased cartilage matrix without apoptosis. In contrast, arthroscopic findings showed an intact joint surface. No recurrence of varus deformity was evident on follow-up at 1 year. Conclusions To the best of our knowledge, this represents the first report of correction osteotomy for varus knee deformity due to premature epiphyseal closure that occurred during treatment with isotretinoin.

An ergonomic upright body posture is maintained by the alignment of the spine, pelvis, and lower extremities, and the muscle strength of body trunk and lower extremities. The posture varies with age because of the degenerative changes in the involved structures and the weakening of the muscles. The compensatory mechanisms underlying these changes have recently been evaluated, and the loss of lumbar lordosis results in spinal kyphosis, pelvic retroversion, hip extension, knee flexion, and ankle dorsiflexion. These mechanisms are referred to as the hip–spine and knee–spine syndromes. The spine, hip, and knee are anatomically connected, and the pain and discomfort of the lower back, hip, and knee frequently arise due to degenerative changes of these structures. Thus, these mechanisms are considered as the knee–hip–spine syndrome. Spinal fusion, total hip arthroplasty, and total knee arthroplasty are the surgical procedures for severe degeneration, and their clinical outcomes for the affected sites are promising. However, despite surgeries, other structures may degenerate and result in complications, such as proximal junctional kyphosis and hip dislocation, following spinal fusion. Therefore, it is necessary to evaluate each patient under specific conditions and to treat each section while considering associations between the target structure and entire body. The purpose of this article is to introduce postural maintenance, variations with age, and improvements with surgical interventions of spine, hip, and knee as the knee–hip–spine syndrome.

Treatment of chronic Monteggia fracture-dislocations remains controversial in skeletally immature patients. The present study aimed to review the clinical outcomes of surgical treatment with an Ilizarov mini-fixator for chronic Monteggia fracture-dislocations in children. From April 2003 to March 2014, 5 pediatric patients (4 males, 1 female) with chronic Monteggia fracture-dislocation were treated with an Ilizarov mini-fixator at our institution. The median age at the time of surgery was 9 years (range 5–14 years), median duration from injury to surgery was 31 months (range 2–125 months), and median duration of follow-up was 12 months (range 11 months–10 years). All patients underwent opening wedge osteotomy of the proximal ulna followed by the application of an Ilizarov mini-fixator. Although closed reduction was attempted after ulnar osteotomy and application of the Ilizarov mini-fixator, open reduction of the radial head was required in all patients. In 4 patients, dense scar tissue in the radiocapitellar joint was excised to enable reduction of the radial head; the remaining patient had traumatic radioulnar synostosis, and underwent separation of the synostosis followed by anconeus interposition arthroplasty. No patient received bone grafting at the ulnar osteotomy site, repair or reconstruction of the annular ligament, or temporary fixation of the radial head with transarticular wire. The median period of external fixation was 10 weeks (range 8–13 weeks). Although there were no severe complications such as deep infection and neurovascular disturbance, asymptomatic radial head subluxation occurred in 2 patients. The patient with traumatic synostosis had residual posterior subluxation with limitation of forearm rotation, and another patient with radial head enlargement had residual anterior subluxation. The median postoperative ranges of motion in pronation, supination, extension, and flexion were 90°, 90°, 0°, and 140°, respectively. The median Kim's elbow performance score was 65 (range 50–75) preoperatively, which improved to 94 (range 80–100) at final follow-up. The outcome was rated as excellent in 4 cases, and good in 1. In pediatric chronic Monteggia fracture-dislocations, ulnar osteotomy followed by the application of an Ilizarov mini-fixator is a viable option that is less invasive than plate fixation.

Background Precise biomechanical knowledge of individual components of the MCL is critical for proper MCL release during TKA. This study was to define the influences of the deep MCL and the POL on valgus and rotatory stability in TKA using cadaveric knees. Methods This study used six fresh-frozen cadaveric knees. All TKA procedures were performed using a cruciate-retaining TKA with a CT-free navigation system. We did a sequential sectioning on each knee, S1; femoral arthroplasty only, S2; medial half tibial resection with spacer, S3; anterior cruciate ligament cut, S4; tibial arthroplasty, S5; release of the dMCL, S6; release of the POL. The navigation system monitored motion after application of 10 N-m valgus loads and 5 N-m internal and external rotation torques to the tibia at 0°, 20°, 30°, 60°, and 90° of knee flexion for each sequence. Results There were no significant differences in medial gaps. Internal rotation angles significantly increased after S2 at 0°, 20°, and 30°, and after S6 at 90°compared with those after S1. External rotation angles significantly increased after S3 at 0°, S4 at 60°, S5 at 0°, 30°and 90°, and after S6 at 30°, 60° compared with those after S1. Conclusion Significant increases of rotatory instability were seen on release of the dMCL, and then further increased after release of the POL. Surgical approach of retaining the dMCL and POL has a possibility to improve the outcome after primary TKA.

[Purpose] This study aimed to compare the efficacy of radiofrequency diathermy with that of microwave diathermy in combination with intra-articular injection of hyaluronic acid into the knee of patients with osteoarthritis (OA). [Subjects] A total of 17 patients with knee OA were enrolled. The participants were randomly divided into two groups: a radiofrequency diathermy group (RF group, 9 subjects), and a microwave diathermy group (MW group, 8 subjects). [Methods] Subjects received radiofrequency or microwave thermal therapy 3 times at 1-week intervals. Intra-articular injection of hyaluronic acid was administered 10 min before every thermal therapy session. The outcome was evaluated using the Japan Orthopaedic Association (JOA) and the Lequesne Index (LI) at baseline, at weeks 1 (1 week after the first thermal therapy) and 3 (1 week after the last thermal therapy). [Results] The JOA scale increased significantly after three sessions of thermal therapy in the RF group, while no significant increase was observed in the MW group. LI decreased significantly after 3 weeks in the RF group. In the MW group, there was no significant difference in LI between the two time points. [Conclusion] This study revealed that symptom relief in patients with knee OA was greater with radiofrequency diathermy than with microwave diathermy with concurrent use of hyaluronic acid injection, presumably due to the different heating characteristics of the two methods.

Aiming to increase the content of type 2 collagen in scaffold-free cartilage-like cell sheets prepared using human bone marrow mesenchymal stem cells, the effect of several kinds of additives in a chondrogenic medium was investigated. Addition of ascorbic acid 2 phosphate (VCP) at a high concentration (250 µg/ml) and type 1 atelocollagen (5 µg/ml) increased the accumulation of type 2 collagen by fourfold and twofold, respectively. On the other hand, an antioxidant, glutathione showed no such effect. The synergistic effect of VCP and type 1 atelocollagen resulted in an eightfold increase in the accumulation level of type 2 collagen. Furthermore, the gene expression level of type 2 collagen increased and that of matrix metalloproteinase-13 (MMP-13) decreased to approximately one-third of the control. The increase in type 2 collagen accumulation in the scaffold-free cartilage-like cell sheet might be due to not only the enhancement of the synthesis but also the suppression of the degradation of type 2 collagen by MMP-13.

Morphological features of the distal femur and proximal tibia associated with cartilage degeneration are unknown. This study aimed to elucidate local anatomical parameters of the knee which correlate with articular cartilage degeneration using MRI T1ρ mapping.This study involved 200 subjects with knee pain (mean age, 48.7 years; range, 14-80 years) with no severe osteoarthritic changes on plain X-ray. T1ρ values were measured in the regions of interest on the surface layer of the cartilage on mid-coronal images of the femorotibial joint. Assessment of medial and lateral posterior tibial slope (MTS, LTS) and medial and lateral femoral condylar offset ratio (MFCOR, LFCOR) was performed using sagittal proton density-weighted imaging. Morphological assessment of posterior root and horn of menisci was also performed according to a modified Whole Organ Magnetic Resonance Imaging Score (WORMS) of the knee.Multiple regression analysis revealed that a decrease in MTS was associated with increased T1ρ values in the medial tibia, independent of age, osteoarthritic changes on plain X-ray, femur-tibia angle (FTA), and posterior medial meniscal lesions.Shallow MTS correlates with cartilage degeneration in symptomatic patients. This parameter could help in understanding the etiology of osteoarthritis in the early stage. Future kinematic studies will be needed to confirm our findings.

Objective Ras guanine nucleotide–releasing protein 4 (RasGRP-4) is a calcium-regulated guanine nucleotide exchange factor and diacylglycerol/phorbol ester receptor not normally expressed in fibroblasts. While RasGRP-4–null mice are resistant to arthritis induced by anti–glucose-6-phosphate isomerase autoantibodies, the relevance of these findings to humans is unknown. We undertook this study to evaluate the importance of RasGRP-4 in the pathogenesis of human and rat arthritis. Methods Synovial tissue from patients with rheumatoid arthritis (RA) and osteoarthritis (OA) were evaluated immunohistochemically for the presence of RasGRP-4 protein. Fibroblast-like synoviocytes (FLS) were isolated from synovial samples, and expression of RasGRP-4 was evaluated by real-time quantitative reverse transcription–polymerase chain reaction analyses. The proliferation potency of FLS was evaluated by exposing the cells to a RasGRP-4–specific small interfering RNA (siRNA). Finally, the ability of RasGRP-4–specific siRNAs to hinder type II collagen–induced arthritis in rats was evaluated to confirm the importance of the signaling protein in the disease. Results Unexpectedly, RasGRP-4 protein was detected in the synovial hyperplastic lining, where proliferating FLS preferentially reside. FLS isolated from tissues obtained from a subpopulation of RA patients expressed much more RasGRP-4 than did FLS from examined OA patients. Moreover, the level of RasGRP-4 transcript was correlated with the FLS proliferation rate. The ability of cultured FLS to divide was diminished when they were treated with RasGRP-4–specific siRNAs. The intraarticular injection of RasGRP-4–specific siRNAs also dampened experimental arthritis in rats. Conclusion RasGRP-4 is aberrantly expressed in FLS and helps regulate their growth. This intracellular signaling protein is therefore a candidate target for dampening proliferative synovitis and joint destruction.