Bilateral subchondral insufficiency fractures of the femoral head in patients with living renal transplantation: A report of two cases

Subchondral stress fracture of the femoral head (SSFFH) in young and healthy military recruits: clinical recommendations and fracture configurations on MRI

PURPOSE

This study aimed to evaluate the clinical and radiologic characteristics of the fatigue-type of SSFFH in healthy military recruits.

MATERIALS AND METHOD

We retrospectively analyzed 39 hips from 32 patients who were treated for SSFFH between 2014 and 2018. Clinical variables were analyzed. We devised a categorization system that divided SSFFH into five types (A-E) according to the extent of the fracture line MRI axial view. The femoral head was divided into three parts for the categorization: the anterior third, middle third, and posterior third.

RESULTS

The included patients were 39 hips from 32 patients with the mean age 22.3 years. Almost all patients with SSFFH (96.9%) complained of hip pain with limping at the time of diagnosis. The mean time to the onset of the hip pain from the beginning of military training was 24.8 days. There were seven patients (21.9%) with concomitant stress fractures on whole-body bone scan. Six hips (15.4%) developed osteoarthritis and required surgery. Almost all the cases (94.9%) involved the anterior compartment of the femoral head.

CONCLUSIONS

Military recruits with the hip pain and limping within one month of military training should undergo detailed evaluation. A whole-body bone scan with SPECT is useful for identifying other concomitant stress fractures. Majority of SSFFH involved the anterior compartment of the femoral head.

Risk factors for subchondral insufficiency fracture of the femoral head in renal transplant patients

INTRODUCTION

Risk factors associated with subchondral insufficiency fracture (SIF) of the femoral head have not been established. The aim of the present study was to determine the incidence and risk factors for SIF of the femoral head following renal transplantation (RT).

MATERIALS AND METHODS

We analyzed the cases of 681 RT patients (mean age at surgery: 49.5 ± 13.6 years, 249 women, 432 men) to determine the incidence of SIF. Hip magnetic resonance imaging (MRI) was performed 6 months post-RT. The following potential predictors of SIF were evaluated: (1) patient's condition at RT: bone mineral density (BMD), pre-RT laboratory values including calcium (Ca), phosphorus (P), calcium-phosphorus product (Ca × P), and intact parathyroid hormone; the patient and donor's blood relationship; and mismatching number of human leukocyte antigens (HLAs), and (2) post-RT dosage(s) of steroid(s), the immunosuppressive regimen, and the incidence of acute rejection.

RESULTS

SIF was observed in 15 hips (13 patients, 1.9%). We successfully matched 39 patients without SIF. A multivariate logistic regression analysis adjusted for cumulative dosages of steroids, revealed the following were risk factors for SIF: osteoporosis (OR: 11.4, p = 0.046), lumbar BMD (OR: 0.003, p = 0.038), pre-RT serum P (OR 2.68, p = 0.004), and pre-RT serum Ca × P (OR: 1.11, p = 0.005).

CONCLUSION

Since osteoporosis, the lumbar BMD, serum P, and serum Ca × P were identified as risk factors for a post-RT SIF, these factors should be evaluated before RT for the prediction of the SIF risk.

Subchondral insufficiency fractures of the femoral head: systematic review of diagnosis, treatment and outcomes

Subchondral insufficiency fractures of the femoral head (SIFFH) are a cause of femoral head collapse leading to degenerative hip disease. SIFFH is often mistaken for osteonecrosis given similar clinical and radiographic features. These similarities often lead to missed or delayed diagnosis which can often delay or change management. The purpose of this article is to systematically review the spectrum of demographics, diagnostic and treatment options, including hip preservation in young patient populations. A systematic review was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. All related peer-reviewed publications from January 1999 to January 2019 were reviewed using the following databases: Medline, EMBASE, Scopus and Web of Science. The systematic review identified 54 articles, encompassing 482 patients (504 hips) diagnosed with SIFFH. One hundred and seventy-six (35%) males and 306 (63%) females were included, with a mean age of 53.6 ± 17.5 years and mean body mass index of 23.4 ± 4.0 kg/m². Mean follow-up was 23.4 ± 15.9 months. Treatment decisions were 256 (55%) non-operative, 157 (34%) total hip arthroplasty (THA), 24 (5%) transtrochanteric anterior rotational osteotomy, 9 (2%) hip arthroscopy, 7 (2%) hip resurfacing, 3 (1%) bone grafting, 3 (1%) hemiarthroplasty and 1 (1%) tantalum rod insertion. Overall, 35% of SIFFH hips were converted to THA at latest follow-up. A majority of SIFFH patients had symptom resolution with non-operative management. Failure most often resulted in THA. In younger patients, hip preservation techniques have shown promising early results and should be considered as an alternative.

Incidence of osteonecrosis and insufficiency fracture of the hip and knee joints based on MRI in 300 renal transplant patients

INTRODUCTION

The purpose of this study was to investigate the incidence of necrosis and insufficiency fracture of the hip and knee using magnetic resonance imaging (MRI) in renal transplant patients.

METHODS

We examined 300 consecutive renal transplant patients using MRI of the hips and knees (T1-weighted coronal MRI) preoperatively and at 3 and 6 months postoperatively. Oblique axial-plane T1-weighted MRI and short-tau inversion-recovery T2-weighted MRI were performed parallel to the femoral neck when distinguishing the osteonecrosis of the femoral head (ONFH) from subchondral insufficiency fracture (SIF) of the femoral head was difficult.

RESULTS

ONFH was observed in 3 hips (3 cases, 1.0%). Osteonecrosis of the knee was observed in 2 knees (1 case, 0.3%). SIF of the femoral head was observed in 5 hips (3 cases, 1.0%). Bilateral simultaneous onset of SIF of the femoral head was observed in 2 cases (0.7%). Insufficiency fracture of the knee was observed in 2 knees (1 case, 0.3%).

CONCLUSIONS

When it was difficult to distinguish ONFH from SIF of the femoral head, oblique axial-plane T1-weighted MRI and the short-tau inversion-recovery T2-weighted MRI parallel to the femoral neck were useful to establish the correct diagnosis.