Michio Hamanishi

Bony impingement depends on the bone morphology of the hip after total hip arthroplasty

PurposeThe purpose of this study was to evaluate whether the bone morphology of the hip affects the range of motion (ROM) in total hip arthroplasty (THA).MethodsUsing the CT data of 63 patients who underwent THA, we calculated the ROM of flexion (Flex), internal rotation (Int-R) and external rotation (Ext-R) using 3D dynamic analysis software. We measured the distance between the anterior surface of the stem and anterior aspect of the greater trochanter (GTa length) at the cutting point and between the tip of the antero-inferior iliac spine (AIIS) and coronal plane of both femoral heads (AIIS length), as a parameter of the femur and pelvis, respectively. The relationship between the ROM, bone anatomy and impingement site was evaluated.ResultsWe found a significant decrease in the ROM of Flex and the Int-R to be inversely proportional to the GTa and AIIS length. In Flex and Int-R, the anterior intertrochanteric region often impinges on the AIIS in patients with larger bone anatomy.ConclusionsWe demonstrated that the bone morphology of the hip substantially affects the ROM of Flex and Int-R, especially in patients with large bone anatomy. For these patients we should consider bony impingement in THA.

Transtrochanteric rotational osteotomy combined with intra-articular procedures for pigmented villonodular synovitis of the hip

Pigmented villonodular synovitis (PVNS) is a relatively rare proliferative disorder termed by Jaffe in 1941 [1]. It is a benign but aggressive disease of the synovium of joints and tendon sheaths, and most frequently occurs in the knee of young individuals. According to Myers and Masi’s literature review of PVNS, 66 % of articular PVNS lesions were in the knee, 16 % in the hip, and 7 % in the ankle, with infrequent cases involving the foot, wrist, shoulder or elbow [2]. The estimated incidence of articular PVNS is 1.8 new cases annually per million population, highlighting the rarity of this disorder [2]. Typically, patients are in the 3rd to 5th decades of life, and it is significantly more frequent in females than in males [3]. The disease is characterized by a unique gross and histological structure consisting of brownish villous and nodular masses arising on the surface of synovial tissues and consisting of fibrous elements, hemosiderin-containing macrophages, lipid cells, multinucleated giant cells, and some inflammatory cells. PVNS of the hip usually presents with diffuse articular involvement, juxta-articular bony lytic lesions, and extensive joint destruction, presumably because of the limited intra-articular space and strong capsular containment [2, 4– 6]. Hip pain resulting from articular PVNS is uncommon and late diagnosis is frequent because most patients present with slow progressive symptoms and radiographs may be normal in the early stages [7–9]. For the treatment of hip PVNS, synovectomy alone or combined with arthroplasty has been selected [4, 9, 10]. Synovectomy, whether via an open approach or arthroscopically, is generally accepted as the most appropriate surgical option [11–13]; however, in cases demonstrating end-stage joint destruction, total hip arthroplasty (THA) combined with open synovectomy is frequently chosen [10–14]. However, THA may be less suitable for patients affected by PVNS because the patients are relatively young and with high functional demands, and joint-preserving procedures should be prioritized as much as possible. Furthermore, there are several reports about poor outcomes of THA due to recurrence or aseptic loosening in patients affected by PVNS [13, 15]. In this report, we present two cases of PVNS of the hip treated with a new treatment strategy which consists of synovectomy and transtrochanteric rotational osteotomy (TRO) [16] combined with intra-articular procedures.

The Cementless Spotorno stem in THA: 10 year results

Background The clinical results of total hip arthroplasty (THA) with a cementless prosthesis have been constantly improving due to progress in the area of stem design and surface finish. Cementless Spotorno stem (CLS stem; Zimmer, Warsaw, USA) is a double-tapered rectangular straight stem. The purpose of this study is to investigate the mean 10 year results of CLS stem and to evaluate the press-fit stability of CLS stem. Methods One hundred and eighty-six consecutive patients (194 hips) were evaluated at more than five years after THA using CLS stems. The mean follow-up period was 111 months. The radiographic stability of the femoral stem was determined by Enghs criteria. The ascertained period of spot welds was noted by Gruen zones on the femoral side. The presence of stress shielding, and subsidence was also evaluated. Results A stable stem with bony on growth was identified in all cases. The mean period of expression of spot welds was 10.8 months in zone 2, 9.9 months in zone 3, 8.5 months in zone 5, and 8.8 months in zone 6. Stress shielding of more than grade 2 was observed in only three hips, which was non-progressive at one year after surgery. Subsidence of more than 2 mm was not observed in any of the hips. Conclusions Excellent stability of CLS stem has been maintained without abnormal bone reaction at the proximal femur. CLS stem is considered to achieve not only press-fit stability at trochanteric and subtrochanteric level, but bony fixation by osseointegration within one year after THA.

Acceleration of healing of the medial collateral ligament of the knee by local administration of synthetic microRNA-210 in a rat model

Background Injury to the medial collateral ligament (MCL) of the knee joint is the most common ligament injury of the knee. Ligament healing generally takes a long time. Micro-ribonucleic acid (miRNA) is one of the noncoding RNAs and plays a crucial role in physiological function; miRNA (miR)-210 is known as a potent factor of angiogenesis, which is an important initiator of ligament healing. The purpose of this study is to examine the effect of local injection of double-stranded (ds) miR-210 on the healing of the MCL of rat knee joint. Methods MCLs of Sprague-Dawley rats were cut transversely. After the fascia and skin were sutured, dsmiR-210 or control dsRNA was injected into the injured site of MCL. At 2 weeks and 4 weeks, histological analysis and immunofluorescence staining of vascular endothelial growth factor, isolectin B4, collagen type 1, and Ki67 as well as a mechanical test were performed. Analysis of complementary deoxyribonucleic acid (cDNA) microarray data was performed at 1 week. Results Histological analysis showed that parallel fibres in the injured site were organised at 2 weeks and became thicker at 4 weeks in the miR-210-treated group, whereas the injured site in controls was filled with loose fibrous tissues and was thinner than that in the miR-210-treated group. The number of blood vessels in the miR-210-treated group was significantly higher than that in controls (p < 0.05), and vascular endothelial growth factor, Ki67, and collagen type 1 in the miR-210-treated group were intensely expressed in the repaired site as compared to the control group. The mechanical test indicated that the ultimate failure load in the miR-210-treated group was significantly higher than that in the control group at 2 weeks. The cDNA microarray analysis showed significant upregulation of genes related to cell proliferation and cell differentiation, and genes involved in negative regulation of apoptosis. Conclusion This study showed that local injection of dsmiR-210 could accelerate MCL healing in rat, which is likely due to stimulation of angiogenesis at the healing site.