Publications by authors named "Tokifumi Majima"

90 Publications

Maturation process of regenerated tissues after single-stage simultaneous autologous particulated cartilage implantation and open wedge high tibial osteotomy for articular cartilage defects with medial osteoarthritis of bilateral knees: a case report.

BMC Musculoskelet Disord 2021 May 31;22(1):502. Epub 2021 May 31.

Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8603, Japan.

Background: Open wedge high tibial osteotomy (OWHTO) is an effective treatment option for young and middle-aged active patients with medial unicompartmental knee osteoarthritis (OA). In addition, particulated cartilage implantation has been developed as a simple procedure for cartilage regeneration. Thus, to improve the OWHTO outcomes, a single-stage, simultaneous bilateral knee arthroscopic particulated cartilage implantation with OWHTO was performed.

Case Presentation: A 60-year-old male patient presented with severe bilateral knee pain, with grade 2 varus knee OA of the Kellgren-Lawrence classification. Primary arthroscopic evaluations based on the International Cartilage Repair Society grading system showed grade 3c articular cartilage defects of 1.5 cm in diameter at the center of the bilateral medial femoral condyles. Following bilateral OWHTO, the healthy cartilage tissue was harvested from the lateral wall of the unilateral femoral intercondylar notch and minced with the cartilage processor. Then, subchondral drillings and cartilage fragment implantations into the bilateral defects were performed arthroscopically. One year postsurgery, second-look arthroscopy findings revealed that the defects were filled with cartilage-like tissues. The maturation process of the regenerated tissues was confirmed with T2 mapping magnetic resonance imaging during the 3-year follow-up period. The patient could walk without a cane, and all Knee Injury and Osteoarthritis Outcome Score parameters were improved without any correction loss in 3 years.

Conclusions: This is the first report to evaluate the maturation process of the implanted particulated cartilage tissue with T2 mapping magnetic resonance imaging for 3 years. The effect of chondral resurfacing procedure with OWHTO remains unclear; however, the implantation of arthroscopic particulated cartilage fragments is a single-stage and less-invasive procedure. This treatment could regenerate cartilage-like tissue in the present case. Therefore, this additional procedure could potentially improve the long-term outcomes of OWHTO.
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http://dx.doi.org/10.1186/s12891-021-04368-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8165777PMC
May 2021

An Isolated Iliac Wing Stress Fracture in a Male Marathon Runner: A Case Report.

JBJS Case Connect 2021 04 19;11(2). Epub 2021 Apr 19.

Department of Orthopaedic Surgery, Nippon Medical School, Tokyo, Japan.

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.
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http://dx.doi.org/10.2106/JBJS.CC.20.00541DOI Listing
April 2021

Venous thromboembolism in major orthopedic surgery.

J Nippon Med Sch 2021 Apr 19. Epub 2021 Apr 19.

Department of Orthopedic surgery, Nippon Medical School.

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.
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http://dx.doi.org/10.1272/jnms.JNMS.2021_88-418DOI Listing
April 2021

Reverse Z-effect phenomenon in a basicervical femoral fracture using cephalomedullary nail with two superior antirotation screws: A case report and procedure evaluation.

Trauma Case Rep 2021 Feb 9;31:100384. Epub 2020 Dec 9.

Department of Orthopedic Surgery, Nippon Medical School Hospital, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan.

We present a case of reverse Z-effect phenomenon in a basicervical femoral fracture using a cephalomedullary nail together with two superior antirotation screws and evaluate the procedure. An 86-year-old woman fell in her home and could not stand due to right hip joint pain. X-ray and CT imaging showed a right basicervical femoral fracture (AO/OTA classification; 31B3), and open reduction and internal fixation (OR/IF) was performed with a cephalomedullary nail and two superior antirotation screws (TES Nail, HOMS, Tokyo, Japan). Two months later, X-ray showed penetration of the femoral head by the inferior lag screw with lateral migration of the two superior antirotation screws; the so-called "reverse Z-effect"; without any trauma. We performed the exchange of a shorter inferior lag screw for the longer one, and replaced the sliding type end cap with one of rocking type. The reverse Z-effect has been reported in cases with two lag screws, i.e. one inferior and one superior, in the past; however, to our knowledge, there has been no case reported in the literature using two superior antirotation screws together with one inferior lag screw.
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http://dx.doi.org/10.1016/j.tcr.2020.100384DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7758364PMC
February 2021

Efficacy of a deep thermal therapy system for osteoarthritis of the knee.

J Nippon Med Sch 2020 Sep 30. Epub 2020 Sep 30.

Department of Orthopaedic Surgery, Nippon Medical School.

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.
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http://dx.doi.org/10.1272/jnms.JNMS.2021_88-505DOI Listing
September 2020

Intratendinous Ganglion in the Extensor Pollicis Longus: A Case Report and Review of Literature.

J Nippon Med Sch 2020 Sep 30. Epub 2020 Sep 30.

Department of Orthopaedic Surgery, Nippon Medical School Hospital.

Ganglion cysts are common benign lesions in the hand and wrist. However, intratendinous ganglion cysts are fairly rare lesions. We present the case of a 73-year-old woman with an intratendinous ganglion cyst occurring in the extensor pollicis longus (EPL) tendon of her right hand. The subcutaneous mass moved according to the movement of the EPL tendon of her right thumb. Magnetic resonance imaging showed a space-occupying lesion in the EPL tendon. Biochemical and hematoimmunological examinations ruled out diabetes mellitus, rheumatoid arthritis and other connective tissue diseases. She complained of a motion pain during thumb extension, and she had desired surgery. Intraoperatively, an intratendinous cyst was identified 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 remarkable proliferative synovial tissue. The EPL tendon was opened longitudinally, and a cystic lesion was enucleated. The pathological findings showed that the cyst wall consisted of fibrous tissue with degeneration, lacking epithelial lining. Postoperative recovery was uneventful. Six months after surgery, the patient had no residual pain and cyst recurrence. The rarity of intratendinous ganglion cysts makes diagnosis and treatment challenging. Since intratendinous ganglion cysts and associated synovitis frequently weaken the structure of the affected tendons, prompt diagnosis and surgical excision are necessary.
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http://dx.doi.org/10.1272/jnms.JNMS.2021_88-416DOI Listing
September 2020

Minimally invasive corrective osteotomy with the Ilizarov mini-fixator for malunited fractures of the phalanges: a technical note.

J Nippon Med Sch 2020 Aug 31. Epub 2020 Aug 31.

Department of Orthopedic Surgery, Nippon Medical School Hospital.

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. Also, abruption of the periosteum and plating of the phalanges require longer bone healing time. The purpose of the present study is to present an easy-to-use and minimally invasive correction of phalangeal malunions using 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 the treatment of phalangeal malunions is still challenging, the procedure introduced in this study is an alternative solution for phalangeal malunions.
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http://dx.doi.org/10.1272/jnms.JNMS.2021_88-314DOI Listing
August 2020

Novel Surgical Procedure for Half Palmaris Longus Transfer during Opponensplasty of the Thumb for Patients with Carpal Tunnel Syndrome: A Technical Note.

J Nippon Med Sch 2021 May 1;88(2):149-153. Epub 2020 Aug 1.

Department of Orthopedic Surgery, Nippon Medical School Hospital.

Thumb opposition is an essential movement for daily use of the hand, including precise pinching/grasping and fine and complicated hand movement. Although studies have reported use of several donor tendons for opponensplasty, opponensplasty using the palmaris longus (i.e., Camitz opponensplasty) has been used in patients with loss of opposition function due to longstanding carpal tunnel syndrome. The procedure involves a simple, useful tendon transfer and does not cause functional deficits. To obtain enough length to transfer the tendon to the metacarpophalangeal joint of the thumb, the PL tendon should be obtained with the palmar aponeurosis. However, the palmar aponeurosis is not always available for opponensplasty, as it is occasionally thin and insufficient for elongation of the palmaris longus. An extended skin incision over the palm can cause painful scar formation and postoperative residual pain. This procedure restores the palmar abduction function of the thumb but not opposition function. In the present article, we describe a modification of Camitz opponensplasty that uses a half-split palmaris longus, which is long enough to anchor to the insertion of the adductor pollicis at the metacarpophalangeal joint of the thumb.
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http://dx.doi.org/10.1272/jnms.JNMS.2020_88-206DOI Listing
May 2021

The Influence of Posterior Cruciate Ligament Resection on Tibiofemoral Joint Gap in Varus Osteoarthritic Knees.

J Knee Surg 2020 Jul 13. Epub 2020 Jul 13.

Department of Orthopaedic Surgery, Nippon Medical School, Bunkyo-ku, Tokyo, Japan.

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 ( < 0.05). However, the increases of the gaps with the ACL and PCL resections were less than 1 mm under the existence of medial soft tissues. As the medial collateral ligament is the primary restraint for the valgus instability, it was also considered to prevent the increase of the flexion gap although the PCL-which is the secondary restraint for the valgus instability-was resected. This finding is critically important for orthopedic surgeons applying PS-TKA implants, particularly for preserving soft tissues to achieve natural knee kinematics postoperatively.
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http://dx.doi.org/10.1055/s-0040-1713810DOI Listing
July 2020

Effect of Medial Osteophyte Removal on Correction of Varus Deformity in Total Knee Arthroplasty.

J Nippon Med Sch 2020 Sep 31;87(4):215-219. Epub 2020 Jan 31.

Department of Orthopaedic Surgery, Nippon Medical School.

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.
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http://dx.doi.org/10.1272/jnms.JNMS.2020_87-503DOI Listing
September 2020

Influence of Total Knee Arthroplasty on Hip Rotational Range of Motion.

J Nippon Med Sch 2020 Sep 27;87(4):191-196. Epub 2019 Dec 27.

Department of Orthopaedic Surgery, Nippon Medical School.

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.
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http://dx.doi.org/10.1272/jnms.JNMS.2020_87-401DOI Listing
September 2020

Three-Dimensional Finite Analysis of the Optimal Alignment of the Tibial Implant in Unicompartmental Knee Arthroplasty.

J Nippon Med Sch 2020 May 15;87(2):60-65. Epub 2019 Oct 15.

Department of Orthopaedic Surgery, Nippon Medical School.

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.
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http://dx.doi.org/10.1272/jnms.JNMS.2020_87-202DOI Listing
May 2020

Knee-Hip-Spine Syndrome: Improvement in Preoperative Abnormal Posture following Total Knee Arthroplasty.

Adv Orthop 2019 1;2019:8484938. Epub 2019 Jul 1.

Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.

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.
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http://dx.doi.org/10.1155/2019/8484938DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6634073PMC
July 2019

Polymorphism in Organic Anion-Transporting Polypeptide Gene Related to Methotrexate Response in Rheumatoid Arthritis Treatment.

J Nippon Med Sch 2019 ;86(3):149-158

Department of Orthopaedic Surgery, Nippon Medical School.

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. 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.
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http://dx.doi.org/10.1272/jnms.JNMS.2019_86-303DOI Listing
December 2019

Correction osteotomy for bilateral varus knee deformity caused by premature epiphyseal closure induced by hypervitaminosis A: a case report.

BMC Musculoskelet Disord 2019 Jun 15;20(1):287. Epub 2019 Jun 15.

Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-Ku, Sapporo, 060-8638, Japan.

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.
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http://dx.doi.org/10.1186/s12891-019-2665-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6570842PMC
June 2019

Ulnar osteotomy and the ilizarov mini-fixator for pediatric chronic monteggia fracture-dislocations.

Medicine (Baltimore) 2019 Jan;98(1):e13978

Department of Orthopaedic Surgery, Nippon Medical School, Tokyo, Japan.

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.
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http://dx.doi.org/10.1097/MD.0000000000013978DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6344151PMC
January 2019

Effects of Endoprosthesis Head Material on Acetabular Cartilage Metabolism: An Animal Study Using Crossbred Pigs.

J Nippon Med Sch 2018 ;85(6):309-314

Department of Orthopedic Surgery, Nippon Medical School.

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.
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http://dx.doi.org/10.1272/jnms.JNMS.2018_85-50DOI Listing
February 2019

Posterior tibial slope angle is associated with flexion-type Salter-Harris II and Watson-Jones type IV fractures of the proximal tibia.

Knee Surg Sports Traumatol Arthrosc 2019 Sep 10;27(9):2994-3000. Epub 2018 Dec 10.

Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8603, Japan.

Purpose: Flexion-type Salter-Harris (SH) II fractures of the proximal tibia, also described as Watson-Jones (WJ) IV fractures, are rare injuries reported among adolescent athletes who are close to skeletal maturity and remain elusive. Due to this classification disagreement, the various treatments range from nonoperative to operative types, and no previous studies have explained the mechanisms of injury or the source of the fracture forces. This retrospective matched case-control study aimed to identify radiological factors that are associated with the fracture forces and to elucidate the mechanisms of these injuries.

Methods: Sixteen flexion-type SH II/WJ IV fractures of the proximal tibia in 12 adolescents (12 males, mean age of 14.6 years) were retrospectively reviewed, and knee alignment on plain radiographs was assessed to compare the radiological outcomes of the operated knees (n = 7), nonoperated knees (n = 9), and uninjured contralateral knees (n = 8). The results were compared to healthy age- and sex-matched control subjects (n = 24 knees).

Results: With regard to the radiological outcomes, the posterior tibial slope angle (PTSA) was significantly greater in the nonoperated knees (19.0° ± 1.6°), operated knees (16.8° ± 1.3°), and uninjured knees (13.6° ± 1.3°) than in the healthy knees of the matched control subjects (9.6° ± 0.4°). The anatomical tibiofemoral angle was significantly less in the nonoperated knees (0.7° ± 0.6°) than in the healthy knees of the matched control subjects (3.7° ± 0.4°).

Conclusions: These findings suggest a relationship between an increased PTSA and flexion-type SH II/WJ IV fractures of the proximal tibia, considering the deteriorating effects of an increased PTSA on knee kinematics. Adolescent active athletes with an increased PTSA and partially closed epiphysis of the proximal tibia are at risk for suffering from flexion-type SH II/WJ IV fractures of the proximal tibia until the closure of the proximal tibial epiphysis.

Level Of Evidence: Case-control study, Level III.
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http://dx.doi.org/10.1007/s00167-018-5319-2DOI Listing
September 2019

A computed-tomography-scan-based template to place the femoral component in accurate rotation with respect to the surgical epicondylar axis in total knee arthroplasty.

Knee 2018 Jan 9;25(1):195-202. Epub 2018 Jan 9.

Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.

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.
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http://dx.doi.org/10.1016/j.knee.2017.11.009DOI Listing
January 2018

In-vivo postoperative motion analysis of metal and ceramic bipolar hip hemiarthroplasty.

J Orthop Sci 2018 Mar 8;23(2):371-376. Epub 2017 Dec 8.

Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan.

Background: We hypothesized that ceramic bipolar shows less impingement between stem neck and outer head compared to metal bipolar, because of its low coefficient of friction with the acetabulum cartilage. In this paper, a three dimensional (3D) postoperative motion analysis has been used to assess the different motion characteristics of metal and ceramic bipolar hip hemiarthroplasty systems.

Methods: This study was conducted on 40 patients divided in two matched cohorts: 20 patients with metal bipolar and 20 patients with the ceramic bipolar. We obtained motion pictures from standing position to maximum abduction in flexion by fluoroscopy then analyzed by 2D-3D image matching method. The motion range of the "Outer head angle", "Stem neck angle" and the "Stem neck and outer head angle" was compared between the metal bipolar group and the ceramic bipolar group.

Results: The metal bipolar group's inner head's range of movement was greater than the ceramic bipolar group. Impingement between stem neck and outer head occurred in 30% of metal group patients. There were no impingement cases for the ceramic bipolar group.

Conclusions: The ceramic bipolar shows less impingement between stem neck and outer head compared to the metal bipolar. Ceramic bipolar may reduce the typical bipolar related complication and exert less effect on the acetabular cartilage due to less surface coefficient of friction.
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http://dx.doi.org/10.1016/j.jos.2017.11.015DOI Listing
March 2018

Preoperative knee deformity and kinematics impact postoperative knee kinematics in total knee arthroplasty.

Knee 2017 Dec 30;24(6):1462-1468. Epub 2017 Sep 30.

Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo 060-8638, Japan; Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5, Senndagi, Bunkyo-ku, Tokyo 113-8603, Japan. Electronic address:

Background: The purpose of this study was to evaluate the relationship between the preoperative knee deformity/kinematic pattern and the postoperative knee kinematic pattern in posterior cruciate ligament substituting (PS)-total knee arthroplasty (TKA).

Methods: This study involved 39 patients with medial osteoarthritis who underwent a primary PS-TKA using a computed-tomography-based navigation system. All the operations were performed by a single surgeon using a subvastus approach, modified gap technique and the same PS type of prosthesis (Genesis II™ total knee system, Smith & Nephew, Memphis, TN, USA). Knee deformity, kinematic pattern after capsule incision (preoperative knee kinematics), and kinematic pattern after implantation (postoperative knee kinematics) in PS-TKA were measured. Kinematic patterns were divided into two groups: a medial pivot group and a non-medial pivot group.

Results: Preoperative varus knee deformity was significantly larger in the non-medial pivot group than in the medial pivot group (femorotibial angle: 184.7±6.4° vs. 180.8±3.9°, P<0.05). In addition, preoperative knee kinematics were conserved postoperatively, at a rate of 82% (P<0.01).

Conclusions: The severity of varus knee deformity and the preoperative knee kinematic pattern might have affected the postoperative knee kinematics in PS-TKA. This must be confirmed with a randomized controlled trial on a large population study.

Level Of Evidence: case control study, Level III.
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http://dx.doi.org/10.1016/j.knee.2017.08.056DOI Listing
December 2017

Bone morphological factors influencing cartilage degeneration in the knee.

Mod Rheumatol 2018 Mar 23;28(2):351-357. Epub 2017 Aug 23.

a Department of Orthopaedic Surgery , Nippon Medical School , Tokyo , Japan.

Objectives: 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.

Methods: 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.

Results: 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.

Conclusions: 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.
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http://dx.doi.org/10.1080/14397595.2017.1332539DOI Listing
March 2018

A pilot study comparing the efficacy of radiofrequency and microwave diathermy in combination with intra-articular injection of hyaluronic acid in knee osteoarthritis.

J Phys Ther Sci 2016 Jan 29;28(2):525-9. Epub 2016 Feb 29.

Departments of Orthopaedic Surgery, Nippon Medical School, Japan.

[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.
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http://dx.doi.org/10.1589/jpts.28.525DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4793004PMC
January 2016

Split Fracture of the Posteromedial Tubercle of the Talus: Case Report and Proposed Classification System.

J Foot Ankle Surg 2017 Jan - Feb;56(1):187-190. Epub 2016 Mar 2.

Department of Orthopaedic Surgery, Nippon Medical School, Tokyo, Japan.

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.
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http://dx.doi.org/10.1053/j.jfas.2016.02.001DOI Listing
August 2017

Influence of the Medial Knee Structures on Valgus and Rotatory Stability in Total Knee Arthroplasty.

J Arthroplasty 2016 Mar 26;31(3):688-93. Epub 2015 Sep 26.

Department of Orthopaedic Surgery, Nippon Medical School, Tokyo, Japan.

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.
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http://dx.doi.org/10.1016/j.arth.2015.09.027DOI Listing
March 2016

Synergistic effect of ascorbic acid and collagen addition on the increase in type 2 collagen accumulation in cartilage-like MSC sheet.

Cytotechnology 2017 Jun 16;69(3):405-416. Epub 2015 Nov 16.

Division of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University, Kita-ku, N13W8, Sapporo, 060-8628, Japan.

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.
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http://dx.doi.org/10.1007/s10616-015-9924-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5461231PMC
June 2017

Medial meniscal posterior root/horn radial tears correlate with cartilage degeneration detected by T1ρ relaxation mapping.

Eur J Radiol 2015 Jun 14;84(6):1098-104. Epub 2015 Mar 14.

Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan. Electronic address:

Objective: This study aimed to identify factors on routine pulse sequence MRI associated with cartilage degeneration observed on T1ρ relaxation mapping.

Materials And Methods: This study included 137 subjects with knee pain. 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 cartilage, subchondral bone, meniscus and ligaments was performed using routine pulse sequence MRI. Radiographic evaluation for osteoarthritis was also performed.

Results: Multiple regression analysis revealed posterior root/horn tears to be independent factors increasing the T1ρ values of the cartilage in the medial compartment of the femorotibial joint. Even when adjusted for radiographically defined early-stage osteoarthritis, medial posterior meniscal radial tears significantly increased the T1ρ values.

Conclusions: This study showed that posterior root/horn radial tears in the medial meniscus are particularly important MRI findings associated with cartilage degeneration observed on T1ρ relaxation mapping. Morphological factors of the medial meniscus on MRI provide findings useful for screening early-stage osteoarthritis.
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http://dx.doi.org/10.1016/j.ejrad.2015.02.008DOI Listing
June 2015

Ras guanine nucleotide-releasing protein 4 is aberrantly expressed in the fibroblast-like synoviocytes of patients with rheumatoid arthritis and controls their proliferation.

Arthritis Rheumatol 2015 Feb;67(2):396-407

Hokkaido University Graduate School of Medicine, Sapporo, Japan.

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.
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http://dx.doi.org/10.1002/art.38924DOI Listing
February 2015

Correlation between knee kinematics and patellofemoral contact pressure in total knee arthroplasty.

J Arthroplasty 2014 Dec 30;29(12):2305-8. Epub 2014 Jul 30.

Department of Orthopedic Surgery, International Univ. of Health and Welfare-Hospital, 537-3, Iguchi, Nasushiobara City, Japan.

The aim of this study is to evaluate the relationship between patellofemoral contact stress and intraoperative knee kinematic patterns after mobile bearing total knee arthroplasty (TKA). Medial osteoarthritic knees of forty-six posterior-stabilized total knee prostheses were evaluated using a computed tomography-guided navigation system. Subjects were divided into two groups based on intraoperative knee kinematic patterns: the medial pivot group (n=19) and the non-medial pivot group (n=27). Mean intraoperative patello-femoral contact stress was significantly lower in the medial pivot group than in the non-medial pivot group (1.7MPa vs. 3.2MPa, P<0.05). An intraoperative medial pivot pattern results in reduced patello-femoral contact stress.
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http://dx.doi.org/10.1016/j.arth.2014.07.020DOI Listing
December 2014

External rotation of the femoral component decreases patellofemoral contact stress in total knee arthroplasty.

Knee Surg Sports Traumatol Arthrosc 2015 Nov 11;23(11):3266-72. Epub 2014 Jun 11.

Department of Orthopedic Surgery, International University of Health and Welfare Hospital, 537-8, Iguchi, Nasushiobara, 329-2763, Japan.

Purpose: The purpose of this study was to investigate the relationship between patellofemoral (PF) contact stress in vivo and the alignment of the femoral component in patients after total knee arthroplasty (TKA).

Methods: Thirty knees with medial compartment osteoarthritis that underwent mobile-bearing TKA with modified gap technique were evaluated. Surgery was performed using a subvastus approach to eliminate the effect of the approach to muscle balance, with a computed tomography-based navigation system (Vector Vision 1.61; Brain Lab, Heimstetten, Germany). PF contact stress was measured by a Flexiforce pressure sensor (Nitta Co., Ltd., Osaka, Japan) intraoperatively, and the results were compared with the alignment of the femoral component after TKA.

Results: The PF contact stress was not correlated with sagittal and coronal alignment of the femoral component and patellar tracking, whereas rotational alignment of the femoral component was negatively correlated with PF contact stress (r = -0.718, p < 0.01).

Conclusions: Regarding the alignment of the femoral component, only the rotational alignment of the femoral component was correlated with PF contact stress. PF contact stress decreased more as the femoral component rotated more externally.

Level Of Evidence: Case control study, Level III.
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http://dx.doi.org/10.1007/s00167-014-3103-5DOI Listing
November 2015