Introduction. Long-term use of bisphosphonates has been known to induce femoral insufficiency fracture in osteoporotic patients. We followed patients who had femoral insufficiency fractures after a long-term use of bisphosphonates. Methods. Eleven patients (14 hips) were diagnosed as having an insufficiency fracture of the femur after long-term (> 4 years) use of bisphosphonate to treat osteoporosis between January 2002 and December 2008. All patients were women who had a mean age of 68 years (range, 57 to 82 years). The fracture site was located in the subtrochanteric area in 6 hips and the femoral shaft in 8 hips. Three patients had bilateral involvement. These patients were followed-up for a mean of 27 months (range, 12 to 60 months). Results. Five hips in five patients displaced during the follow-up period. The mean period from the diagnosis of insufficiency fracture to the displacement was 10 months (range, 1 to 19 months). Five hips (five patients) underwent internal fixation due to persistent pain. Thus, during the follow-up of 27 months, operation was necessary in 71% (10 hips) of 14 insufficiency fractures. Four hips (four patients) that did not undergo any operation had persistent pain at the latest follow-up. Conclusion. The insufficiency fractures after prolonged bisphosphonate therapy seldom healed spontaneously and most of them required operation due to fracture displacement or persistent pain. We recommend preventive surgery to prevent further fracture displacement and persistent pain

Introduction. Subchondral insufficiency fractures of the femoral head (SIFFH) occur with normal or physiological stress in patients with poor bone quality. We evaluated the clinical characteristics of SIFFH. Methods. Nine cases of SIFFH were treated and followed up for an average of 9 months. Femoral head collapse (FHC) on radiographs was classified as minimal (< 2 mm), moderate (2-4 mm), and severe (> 4 mm). The severity of osteopenia was scored by Singh index (SI). Other characteristics of SIFFH were ascertained by assessing the clinical course as well as Body Mass Index (BMI) and magnetic resonance imaging (MRI). Results. There were 8 women and 1 man who had a mean age of 67 years. FHC was identified in 6 cases (1 minimal, 3 moderate, and 2 severe). SI scores ranged from 1 to 4. Mean BMI was 22.4 Kg/m. 2. In all affected hips, MRI demonstrated a subchondral fracture line with localized or diffuse bone-marrow-edema pattern in the femoral head. Initially, all cases were treated with conservative nonweight bearing therapy. In 7 of 9 cases, the pain decreased gradually and disappeared almost completely within 5 months regardless of the extent of FHC, SI score, and BMI. The remaining 2 cases (1 moderate and 1 severe FHC) were treated with total hip arthroplasty due to intractable pain. Conclusion. This study showed that conservative treatment could be considered as the first treatment choice for SIFFH independent of predisposing factors

Similar to the radiological findings in rapidly destructive arthrosis of the hip joint (RDA), subchondral insufficiency fracture of the femoral head (SIF) can result in progressive femoral head collapse of unknown etiology. We thus examined the osteoclast activity in hip joint fluid in SIF with progressive collapse in comparison to that in RDA. Twenty-nine hip joint fluid samples were obtained intraoperatively with whole femoral heads from 12 SIF patients and 17 RDA patients. SIF cases were classified into subgroups based on the presence of ≥2mm collapse on preoperative radiographs: SIF with progressive collapse (n=5) and SIF without progressive collapse (n=7). The levels of tartrate-resistant acid phosphatase (TRACP)-5b, interleukin-8, vascular endothelial growth factor (VEGF), and matrix metalloproteinase (MMP)-9 were measured. Numbers of multinuclear giant cells at the subchondral region were assessed histopathologically using mid-coronal slices of each femoral head specimen. Median levels of all markers and median numbers of multinuclear giant cells in SIF with progressive collapse were significantly higher than those in SIF without progressive collapse, while there were no significant differences in SIF with progressive collapse versus RDA. Regression analysis showed that the number of multinuclear giant cells correlated positively with the level of TRACP-5b in joint fluid. This study suggests an association of increased osteoclast activity with the existing condition of progressive collapse in SIF, which was quite similar to the findings in RDA. Therefore, high activation of osteoclast cell may reflect the condition of progressive collapse in SIF as well as RDA

Introduction. Subchondral insufficiency fracture of the femoral head (SIF) often occurs in osteoporotic elderly patients. Patients usually suffer from acute hip pain without any obvious antecedent trauma. Radiologically, a subchondral fracture is seen mainly in the superolateral portion of the femoral head. The T1-weighted magnetic resonance (MR) images show a low-intensity band in the subchondral area of the femoral head, which tends to be irregular, disconnected, and convex to the articular surface. This low-intensity band in SIF was histologically proven to correspond to the fracture line with associated repair tissue. Some cases of SIF resolve after conservative treatment, while others progress until collapse, thereby requiring surgical treatment. The prognosis of SIF remains unclear. This study investigated the risk factors that influence the prognosis of SIF based on the progression of the collapse. Methods. Between June 2002 and June 2008, seventeen patients diagnosed as SIF were included in this study. Sequential radiographs were evaluated for the presence of progression of the collapse. The clinical profiles, including the age, body mass index (BMI), follow-up period and Singh index were examined. The morphological characteristics of the low intensity band on the T1-weighted magnetic resonance images were also examined, with regard to the band length, band thickness and band length ratio; which is defined as a proportion of the band length to the weight-bearing portion of the femoral head. Results. Radiographically, a progression of the collapse was observed in 8 of 17 (47.1%) patients. The band length in patients with progression of the collapse (mean: 22.6 mm) was significantly larger than that in those without progression of the collapse (mean: 12.3 mm; P < 0.05). The band length ratio in patients with progression of the collapse (mean: 73.3 %) was also significantly higher than that in those without progression of the collapse (mean: 42.3 %; P < 0.01). No significant differences were seen in the other variables (the age, BMI, follow-up period, Singh index, and band thickness). Conclusion. One of the important differential diagnoses in determining SIF may include osteonecrosis. The shape of the low signal intensity band on the T1-weighted MR images is one of the characteristic findings in SIF: namely, it is generally irregular, serpiginous, convex to the articular surface, and often discontinuous. This low-intensity band is generally surrounded by bone marrow edema. Histopathologically the band in SIF represents the fracture line with associated repair tissue. On the other hand, in osteonecrosis, since the low-intensity band represents repair tissue, it is generally smooth and circumscribes all of the necrotic segments. In this study, the prognosis of SIF varied even though all the patients received similar non-operative treatments. If the prognosis for SIF can be predicted at the early stage, it would allow the design of optimal treatments in each patient. In this preliminary investigation, both the band length and band length ratio were demonstrated to be useful when selecting the optimal treatment for SIF

Introduction. Subchondral insufficiency fracture of the femoral head (SIF) is a recently proposed concept. It is generally seen in elderly people, however, some young adults have also been reported to suffer from this fracture. The purpose of this study was to investigate the clinical results of a transtrochanteric anterior rotational osteotomy (ARO) performed in young adults with SIF. Methods. This study focused on young SIF cases (age range from 10 to 29 years). Five patients were diagnosed to have SIF at our institution and conservative treatment was initially performed. The symptoms resolved in 1 case while the other 4 cases showed progression of a collapse. In these 4 cases, ARO was performed, since the fractured area was located in the anterosuperior portion of the femoral head. The average age of the patients was 22 years (range, 16 to 29 years) at the time of surgery, consisting of 2 men and 2 women. Results. All cases were followed-up and the average follow-up period was 3.4 years (range, 1.8 to 6.8 years). The average preoperative Harris hip score was 67 points, which improved to an average of 93 points at the latest follow-up. Radiographically, the fractured lesion healed and no progression of a collapse was observed in any of the 4 cases. Conclusion. In the majority of SIF cases, only the anterosuperior portion of the femoral head is involved by the fracture. When considering the optimal surgical treatments for SIF, ARO may be one of the useful options, especially for the treatment of young patients

Introduction. The incidence of distal femoral fractures in the geriatric population is growing and represents the second most common insufficiency fracture of the femur following fractures around the hip joint. Fixation of fractures in patients with poor bone stock and early mobilisation in feeble and polymorbide patients is challenging. Development of a fixation approach for augmentation of conventional LISS (less invasive stabilization system) plating may result in superior long-term clinical outcomes and enhance safe weight bearing. Objectives. The aim of this study was to investigate the biomechanical competence of two different techniques of augmented LISS plating for treatment of osteoporotic fractures of the distal femur in comparison to conventional LISS plating. Materials & methods. Unstable distal femoral fracture AO/OTA 33-A3 was set in artificial femora with low density simulating osteoporotic bone. Three study groups, consisting of 10 specimens each, were created for instrumentation with a 9-hole LISS plate, a LISS plate with an additional 3D-printed polyactide cylindrical intramedullary graft, as well as a LISS plate plus a medial 3.5mm LCP (locking compression plate) - double plating. All specimens were non-destructively tested under axial (20–150N) and torsional (0–4Nm) quasi-static loading. Each construct was tested with two different working length (WL) configurations (long and short) of the LISS plate. Relative movements between the most medial superior and inferior osteotomy aspects were investigated via three-dimensional motion tracking analysis. Results. Interfragmentary displacement along the femur axis (mm) under 150N axial loading was 2.03±0.23/1.65±0.27 for LISS with long/short WL, 0.18±0.06/0.18±0.04 for double plating with long/short WL, and 0.40±0.05/0.30±0.05 for LISS plus graft with long/short WL. Shear interfragmentary displacement (mm) under 4Nm torsional loading in internal rotation was 1.16±0.17/0.92±0.11 for LISS with long/short WL, 0.40±0.10/0.43±0.07 for double plating with long/short WL, and 1.09±0.13/0.82±0.11 for LISS plus graft with long/short WL. Double plating revealed significantly smaller longitudinal and shear displacement compared to the other two techniques for long and short WL, respectively (P≤0.010). In addition, LISS plus graft fixation was with significantly less longitudinal displacement in comparison to conventional LISS plating for long and short WL, respectively (P≤0.001). Long WL resulted in significantly higher longitudinal and shear displacement compared to short WL for LISS and LISS plus graft (P≤0.032), but not for double plating (P=1.000). Conclusion. Intramedullary grafting resulted in significantly increased fracture stability under axial loading in comparison to conventional LISS plating. However, it was not efficient enough to achieve comparable stability to double plating

Medial meniscus tear has been proposed as a potential etiology of spontaneous osteonecrosis of the knee (SONK). Disruption of collagen fibers within the meniscus causes meniscal extrusion, which results in alteration in load distribution in the knee. A recent study has demonstrated high incidence of medial meniscus extrusion in the knee with SONK. Our purpose was to determine whether the extent of medial meniscus extrusion correlates with the severity of SONK in the medial femoral condyle. Anteroposterior and lateral knee radiographs were taken with the patients standing. Limb alignment was expressed as the femorotibial angle (FTA) obtained from the anteroposterior radiograph. The stage of progression of SONK was determined according to the radiological classification system described by Koshino. After measurement of anteroposterior, mediolateral, and superoinferior dimensions of the hypointense T1 signal intensity lesion of MRI, its ellipsoid volume was calculated with the three dimensions. Meniscal pathology (degeneration, tear, and extrusion) were also evaluated by MRI. Of the 18 knees with SONK, we found 5 knees at the radiological stage 2 lesions, 9 knees at the stage 3, and 4 knees at the stage 4. Whereas the ellipsoid volume of SONK lesion significantly increased with the stage progression, the volume was significantly greater at stage 4 than stage 2 or 3. All the 18 knees with SONK in the present study showed substantial extrusion (> 3mm) and degeneration of the medial meniscus. While medial meniscal extrusion increased with the stage progression, medial meniscus was significantly extruded at stage 3 or 4 compared with stage 2. A significant increase in FTA was found with the stage progression. FTA was significantly greater at stage 4 than stage 2 or 3. Multiple linear regression analysis revealed that medial meniscus extrusion and FTA were useful predictors of the volume of SONK lesion. This study has clearly shown a significant correlation between the extent of medial meniscus extrusion and the stage and volume of SONK lesion. Degeneration and tears of the medial meniscus in combination with extrusion may result in loss of hoop stress distribution in the medial compartment, which could increase the load in the medial femoral condyle. In addition to meniscal pathology, knee alignment can influence load distribution in the medial compartment biomechanically. Multiple linear regression analysis indicates that an increase in FTA concomitant with a greater extrusion of medial meniscus could result in greater lesion and advanced radiological stage of SONK. Taken together, alteration in compressive force transmission through the medial compartment by meniscus extrusion and varus alignment could develop subchondral insufficiency fractures in the medial femoral condyle, which is considered to be one of the main contributing factors to SONK development. There was high association of medial meniscus extrusion and FTA with the radiological stage and volume of SONK lesion. Increased loading in the medial femoral condyle with greater extrusion of medial meniscus and varus alignment may contribute to expansion and secondary osteoarthritic changes of SONK lesion

Introduction. Subchondral insufficiency fracture (SIF) needs to be differentiated from osteonecrosis. The purpose of this study was to evaluate the imaging and histopathological findings of patients 60 years or older with radiological evidence of subchondral collapse of the femoral head. Methods. We reviewed 77 consecutive hips in 56 patients aged 60 years or older, which showed subchondral collapse on radiographs. According to the shapes of low-intensity bands on T1-weighted images of magnetic resonance imaging (MRI), the patients were divided into 2 groups. Group A showed a concavity of the articular surface: characteristic appearances of osteonecrosis, and Group B showed an irregular convexity of the articular surface: characteristic appearances of SIF. Results. Thirty-four patients (60.7%) were categorized as Group A and 22 patients (39.3%) as Group B. All the cases in Group A had a history of corticosteroid intake or alcohol abuse. In Group B, the proportion of women as well as unilateral involvement was significantly higher than those in Group A. In 30 cases with histopathological examination, 16 were in Group A and 14 were in Group B. All the cases in Group A demonstrated characteristic features of osteonecrosis. In Group B, the band on T1-weighted images corresponded to viable reparative tissue including granulation tissue and fracture callus, which are characteristic histological findings in SIF. Conclusion. The results of this study suggest that the patient's clinical features as well as the shapes of the low-intensity bands on T1-weighted images provide a clinically concise tool for the differentiation of SIF from osteonecrosis