Transient bone marrow edema syndrome of the knee: clinical and magnetic resonance imaging results at 5 years after core decompression

A systematic review of the use of shockwave therapy for knee osteoarthritis

Introduction

Previous studies assessed the effect of extracorporeal shockwave therapy (ESWT) for knee osteoarthritis (OA) among different situations. Thus, results from a meta-analysis regarding this topic may not be reliable due to heterogeneity.

Methods

A systematic review was conducted on three internet databases, namely Cochrane Library, PubMed, and Embase, gathering pertinent papers from their establishment to March 2024. The search phrases were as follows: "shockwave" OR "shock wave" OR "extracorporeal shockwave" OR "Extracorporeal Shockwave Therapy [MeSH Term]" AND "knee" AND ("osteoarthritis" OR "arthritis" OR "arthritic" OR "osteoarthritis [MeSH term]").

Results

Twenty-four articles (n = 888) were included, with the resulting conclusions demonstrating that ESWT was effective for knee OA compared with sham ESWT; however, ESWT was not effective for patients with severe knee OA. Patients receiving higher energy or higher shock number had significant improvement than those receiving lower energy or less shock number, respectively. Adding ESWT in isokinetic muscular strengthening exercises (IMSE) was more effective than IMSE alone. The efficacy of ESWT was better than other therapies, including intravenously applied prostacyclin and bisphosphonate, corticosteroid injection, kinesiotherapy, hyaluronic acid injection, platelet-rich plasma injection, and physiotherapy.

Conclusions

This review demonstrated that ESWT was effective for knee OA. Higher energy and more shock numbers could obtain better efficacy. ESWT could be used as a replacement for some other therapies.

Spontaneous Bone Marrow Edema: Perfusion Abnormalities and Treatment with Surgical Decompression

Bone marrow edema (BME), also termed bone marrow lesions, is a syndrome characterized by bone pain and the appearance of high signal intensity on T2 fat-suppressed and short tau inversion recovery (STIR) MRI sequences. BME can be related to trauma or a variety of non-traumatic diseases, and current treatment modalities include non-steroidal anti-inflammatory drugs (NSAIDS), bisphosphonates, denosumab, extracorporeal shockwave therapy (ESWT), the vasoactive prostacyclin analogue iloprost, and surgical decompression. Spontaneous BME is a subset that has been observed with no apparent causative conditions. It is most likely caused by venous outflow obstruction and intraosseous hypertension. These are mechanistically related to impaired perfusion and ischemia in several models of BME and are related to bone remodeling. The association of perfusion abnormalities and bone pain provides the pathophysiological rationale for surgical decompression. We present a case of spontaneous BME and a second case of spontaneous migratory BME treated with surgical decompression and demonstrate resolution of pain and the high signal intensity on MRI. This report provides an integration of the clinical syndrome, MR imaging characteristics, circulatory pathophysiology, and treatment. It draws upon several studies to suggest that both the bone pain and the MRI characteristics are related to venous stasis, and when circulatory pathologies are relieved by decompression or fenestration, both the bone pain and the MRI signal abnormalities resolve.

Mosaicplasty With High Tibial Osteotomy for Knee Subchondral Insufficiency Fracture Had Better Magnetic Resonance Observation of Cartilage Repair Tissue Scores With Less Bone Marrow Edema and Better Plug Union and Less Plug Necrosis Compared With Mosaicplasty Alone

PURPOSE

To determine the magnetic resonance imaging (MRI) findings after mosaicplasty (MOS) for knee subchondral insufficiency fracture (SIFK), and to analyze the relationship between MRI findings and clinical outcomes.

METHODS

We retrospectively reviewed the cases of consecutive patients who underwent MOS for SIFK with/without high tibial osteotomy (HTO) between January 1998 and December 2015. The MRI findings at 12 months after the surgery were assessed by the modified magnetic resonance observation of cartilage repair tissue (MOCART) score to determine the degree of bone marrow edema (BME), plug union, and plug necrosis. The clinical outcomes were assessed by Lysholm score to clarify the minimal clinically important difference (MCID) and patient acceptable symptom state analysis.

RESULTS

In total, 58 patients (17 men and 41 women) were enrolled in this study. Among them, 30 knees were treated by MOS alone and 28 knees were treated by MOS with HTO. The MOCART scores of patients who received MOS alone were significantly lower in BME score (P = .0060), plug union score (P = .0216), and in plug necrosis score (P = .0326) than patients who received MOS with HTO. BME lesion was less likely to persist among elderly (odds ratio 1.20, P = .0248) and female (OR 41.8, P = .0118) patients. The MCID of Lysholm score was 6.6 in MOS alone and 8.4 in MOS with HTO cases, but there were no significant association between MRI findings and the postoperative Lysholm score.

CONCLUSIONS

The MOS with HTO cases had better MOCART scores with less BME, better plug union, and less plug necrosis compared with MOS alone cases. Female and older patients had better resolution of BME, but there was no significant correlation between MRI findings and the postoperative Lysholm score. All cases in both groups showed improvement of Lysholm score exceeding MCID; thus, MOS may be effective as a joint preserving surgery for SIFK.

LEVEL OF EVIDENCE

Level IV, clinical case series.

Comparison of various treatment modalities for the management of bone marrow edema syndrome/transient osteoporosis in men and non-pregnant women: a systematic review

Transient osteoporosis (TO) or bone marrow edema syndrome (BMES) is a self-limited clinical condition, which affects middle-aged men and women. It can be treated with miscellaneous conservative and surgical measures, which are analyzed in this systematic review.

INTRODUCTION

BMES/TO is a transient clinical entity, which can be treated with various therapeutic modalities. The aim of our study was to assess the efficacy of different therapeutic options for the alleviation of pain and reduction of bone marrow edema (BME) in patients with BMES/TO, as well as to propose a therapeutic algorithm.

METHODS

PubMed, Scopus, Cochrane, and Google Scholar were searched. Eligibility and extraction of studies were conducted by two authors. Methodological quality assessment was carried out with the modified Delphi technique, Methodological Index for Non-Randomized Studies (MINORS) criteria, and Cochrane Collaboration's risk of bias tool. Outcomes that were compared were time of pain resolution, VAS pain scores, and BME regression on magnetic resonance imaging (MRI).

RESULTS

A total of 36 articles (880 patients) were included. Bisphosphonates had higher efficiency in less than 1-month outcomes on pain resolution compared with core decompression (CD), while iloprost was more efficient at 1-3 months compared with bisphosphonates and CD. At 3-6 months, all three of the aforementioned showed equal results on pain resolution, and at a period of 6-12 months, CD and extracorporeal shockwave therapy (ESWT) showed excellent results followed by bisphosphonates and the conservative group (CG) consisting of non-steroidal anti-inflammatory drugs (NSAIDs) and/or analgesics and/or restricted weight bearing. On MRI at 1-3 months, bisphosphonates, iloprost, and CD had relatively the same outcomes on BME resolution, with the least promising being the CG. At 3-6 months, CD seemed to have achieved the best results on the resolution of BME, followed by ESWT, CG, and bisphosphonates group. At 6-12 months, ESWT had the best outcomes compared with the conservative, bisphosphonates, and iloprost groups.

CONCLUSION

BMES/TO has been treated with many non-standardized measures due to the low number of highly reliable studies. Current literature shows promising results with regard to the reduction of the clinical course of BMES/TO, but further large multicenter randomized controlled trials, as well as standardized radiological and clinical scores, are warranted to acquire evidence-based recommendations on the therapeutic algorithm.

Bone Marrow Edema, Clinical Significance, and Treatment Options: A Review

Bone marrow edema (BME) is a descriptive term used to describe high-signal intensity changes detected on magnetic resonance fluid-sensitive sequences that could be attributed to a number of underlying pathologies. Regardless of the cause, physiologic remodeling of the subchondral bone can be limited because of ongoing joint forces, increased focalization of stress, and reduced healing capacity of the subchondral bone. BME is a known prognostic factor associated with pain, dysfunction, and progressive cartilage damage. This review summarizes the current known causes of BMEs, theories related to histopathological changes, and current treatment options including novel biologic surgical options.

Bone marrow oedema syndrome of the foot and ankle in a paediatric population: a retrospective case series with serial MRI evaluation

PURPOSE

By means of a case series we wanted to describe and correlate the clinical and imaging features of bone marrow oedema syndrome (BMOS) of the foot and ankle in children.

METHODS

A retrospective data study was performed on patients born on or after 01 January 2001 who underwent multiple MRI scans of the foot and ankle for pain symptoms. Six patients who presented with increased signal intensity on T2-weighted MR imaging without any underlying causes or concomitant pathology were included.

RESULTS

All patients, three boys and three girls with a mean age of 11 years (8 to 14), displayed patchy areas of increased signal intensity on T2-weighted and turbo inversion recovery magnitude (TIRM) images. On average, six tarsal bones were involved (4 to 8). In all patients, treatment consisted of rest and/or protected weight-bearing. The mean time for symptoms to improve during treatment was 6 months (1 to 16). The mean duration of treatment was nine months (3 to 16). In all patients clinical and imaging symptoms were strongly correlated and regressed in time.

CONCLUSION

BMOS as a pathological entity should be considered in paediatric patients with foot and ankle pain without a clear underlying cause, and characteristic T2-weighted and TIRM signal intensity increase on MRI images. As BMOS is transient and self-limiting, conservative treatment is advised while the oedema regresses. An early diagnosis of this pathology could prevent unnecessary diagnostic investigations and invasive treatments.

LEVEL OF EVIDENCE

IV.

Identification of bone marrow edema of the knee: diagnostic accuracy of dual-energy CT in comparison with MRI

BACKGROUND

To assess the diagnostic accuracy of dual-energy computed tomography (DECT) in diagnosing bone marrow edema (BME) of the knee in traumatic and non-traumatic patients.

METHODS

This prospective IRB approved study included 33 consecutive patients (20 males, 13 females; mean age of 52.2 years) evaluated with DECT (80 and 150 kV) and MRI within 6 days. Two experienced radiologists qualitatively and quantitatively evaluated DECT images. The accuracy values were calculated by using receiver operator curves (ROC) and area under the curve (AUC), using MRI as the reference standard. Inter-observer and intra-observer agreement were calculated with k-statistics. A p < 0.05 was considered statistically significant.

RESULTS

MRI depicted BME in 25/33 patients (75.7%). The sensitivity, specificity, PPV, NPV, and accuracy of per-partition qualitative analysis were 92.9, 92.9, 78.2, 97.9, and 92.9%, for reader 1, and 88.2, 93.9, 79.8, 96.6, and 92.6%, for reader 2, respectively. The inter-observer agreement was substantial (k = 0.793) and the intra-observer agreement was near-perfect (k = 0.844). At the quantitative analysis, a significant difference (p < 0.001) was depicted between the density values of positive (mean 3.6 ± 25.3 HU) and negative cases (mean - 72.2 ± 45.1 HU). By using - 15 HU cutoff to identify BME, sensitivity, specificity, PPV, NPV, and accuracy of DECT were 84.7, 93.6, 78.2, 95.7, and 91.6%, respectively.

CONCLUSION

DECT can accurately identify BME of the knee.

Clinical effect of intramuscular calcitonin compared with oral celecoxib in the treatment of knee bone marrow lesions: a retrospective study

BACKGROUND

Bone marrow lesions (BMLs) are a common finding in patients with osteoarthritis (OA), which are predictors of progression and pain related to cartilage damage in OA. The objective of the present research was to compare the short-term clinical effect of intramuscular calcitonin and oral celecoxib in treating knee BMLs.

PATIENTS AND METHODS

Between January 2016 and December 2018, the medical records of patients with knee BMLs treated by intramuscular calcitonin or oral celecoxib were reviewed. Visual analog scale (VAS) and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) were used to assess knee pain and function, respectively. BMLs were assessed by MRI scans and were scored by the modified Whole-Organ MRI Score (WORMS). The safety of these two medications was also evaluated.

RESULTS

A total of 123 eligible patients who received calcitonin treatment (n = 66) or celecoxib treatment (n = 57) were included. All patients were followed up clinically and radiographically for 3 months. The VAS and WOMAC scores were lower statistically in calcitonin group than celecoxib group at 4-week and 3-month follow-up. For BMLs, the WORMS scores in the calcitonin group were significantly lower than the celecoxib group. Besides, statistically higher MRI improvement rates were found in the calcitonin group compared with the celecoxib group at 4-week follow-up (21.21% vs. 7.01%; P = 0.039) and 3-month follow-up (37.88% vs. 15.79%; P = 0.006).

CONCLUSION

Intramuscular calcitonin 50 IU once daily demonstrated a better short-term effect for knee BML patients compared with oral celecoxib 200 mg twice per day.

How We Manage Bone Marrow Edema-An Interdisciplinary Approach

Bone marrow edema (BME) is a descriptive term for a common finding in magnetic resonance imaging (MRI). Although pain is the major symptom, BME differs in terms of its causal mechanisms, underlying disease, as well as treatment and prognosis. This complexity together with the lack of evidence-based guidelines, frequently makes the identification of underlying conditions and its management a major challenge. Unnecessary multiple consultations and delays in diagnosis as well as therapy indicate a need for interdisciplinary clinical recommendations. Therefore, an interdisciplinary task force was set up within our large osteology center consisting of specialists from internal medicine, endocrinology/diabetology, hematology/oncology, orthopedics, pediatrics, physical medicine, radiology, rheumatology, and trauma surgery to develop a consenus paper. After review of literature, review of practical experiences (expert opinion), and determination of consensus findings, an overview and an algorithm were developed with concise summaries of relevant aspects of the respective underlying disease including diagnostic measures, clinical features, differential diagnosis and treatment of BME. Together, our single-center consensus review on the management of BME may help improve the quality of care for these patients.

Surgical modalities for the management of bone marrow edema of the knee joint

Background

Bone marrow edema (BME) is a radiological term which can be found in many conditions with varied pathogenesis and histopathological images. It usually presents with pain in the affected joint and is diagnosed with MRI. Subchondroplasty (SCP) and core decompression (CD) are the surgical methods that are available to achieve pain relief and functional improvement. Both surgical methods have their own indications and are used depending on the patient's history. The aim of this literature review article is to discuss the surgical modalities for the management of bone marrow edema focusing on the knee joint. Such topic which analyzes both surgical methods for treatment of bone marrow edema of the knee joint has never been described in a review article before.

Materials and methods

For the purpose of our manuscript we thoroughly searched electronic databases such as Pubmed and Medline to acquire the appropriate material for our review paper. Only English articles were used in this review. In our study we included every article that had described the surgical management of BME of the knee by CD and SCP. In the discussion we included 18 studies (9 CD and 9 SCP) with a total number of patients equal to 397, while 206/397 had undergone surgical intervention (169 underwent SCP and 37 CD).

Results

Follow-up of 180 patients out of 206 were available for our review. A total number of 166 patients (92.2%) were successfully treated. Specifically, 29 (100%) patients were treated by CD and 137 (90.7%) by SCP. In a study, 10 patients who underwent SCP for BME secondary to advanced osteoarthritis (OA) yielded poor results. In other studies, pain persistency was observed in 2 patients, 1 patient had postoperative infection and another patient eventually underwent total knee arthroplasty (TKA). 70% prevention of TKA was achieved by SCP in a study of 66 patients with BME secondary to advanced OA. Thus, a total number of 166 patients were considered as clinical success and 14 patients as clinical failure.

Conclusions

The included studies that have been published referred to the surgical methods of CD or SCP for the management of BME of the knee but none of that summarizes all current studies on both methods. Those studies seem that CD is a surgical technique that is proposed to perform in patients without findings of OA that usually fail to respond to conservative treatment. On the other hand, the option of SCP technique is carried out in patients with varied stage of OA associated with subchondral BME. Both methods aim to reduce the pain and to improve function in the setting of subchondral BME. Nevertheless it is not clear in literature which method is the best according to the criteria of the use. This literature review shows a lack of standardized guidelines with respect to diagnosis and surgical treatment.

Technologies in the Treatment of Bone Marrow Edema Syndrome

Bone marrow edema syndrome is a rare and self-limited syndrome with an unknown cause. The natural time course for improvement of clinical symptoms and normalization in MRI lasts from 3 to 18 months. This entity must be distinguished from other causes of marrow abnormality, such as stress fractures and osteonecrosis, for the best treatment options. Various treatments from conservative to surgical have been made to provide pain relief and accelerate the natural course of the disease. This article reviews bone marrow edema syndrome with a focus on treatment in the foot and ankle.

Extracorporeal shock wave treatment can normalize painful bone marrow edema in knee osteoarthritis: A comparative historical cohort study

Bone marrow edema (BME) represents a reversible but highly painful finding in magnetic resonance imaging (MRI) of patients with knee osteoarthritis. The aim of this retrospective study was to evaluate the efficacy of extracorporeal shock wave treatment (ESWT) on painful BME in osteoarthritis of the knee.This study focuses on people who had early-to-mid stage osteoarthritis with knee pain and MRI findings of BME. Patients who underwent ESWT treatment or prescribed alendronate treatment in our department were analyzed. Knee pain and function were measured using the visual analog scale (VAS) for pain and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC), respectively. The degree of BME was measured with MRI scans.A total of 126 patients who received ESWT treatment (Group A, n = 82) or alendronate treatment (Group B, n = 44) were included. All patients were followed up clinically and radiographically for a minimum of 12 months. The mean follow-up was 23.5 months (range, 12-38 months). The VAS and WOMAC score decreased more significantly after treatment in Group A than that in Group B (P <.01) within 3 months. In 6-month MRI follow-ups, there was higher incidence of distinct reduction and complete regression of BME of the affected knee in Group A than that in Group B (P <.01).ESWT is an effective, reliable, and noninvasive treatment in patients with painful BME in osteoarthritis of the knee followed by a rapid normalization of the MRI appearance. It has the potential to shorten the natural course of this disease.

Extracorporeal Shock Wave Therapy Is Effective in the Treatment of Bone Marrow Edema of the Medial Compartment of the Knee: A Comparative Study

OBJECTIVE

To test the hypothesis that shock wave therapy can produce a statistically significant improvement in symptoms and imaging features of the knee bone marrow edema syndrome (BMES) within 6 months of treatment.

SUBJECTS AND METHODS

Eighty-six consecutive patients suffering from BMES of the medial compartment of the knee were prescribed a course of high-energy extracorporeal shock wave therapy (ESWT) and clinically followed up at 3 and 6 months and finally from 14 to approximately 18 months after treatment. Thirty-one patients were unable to undergo ESWT but returned for the 6-month and final follow-up; these were referred to as the conservative (control) group, while the other 55 patients constituted the ESWT group. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Visual Analog Scale (VAS) score of each patient were calculated at every follow-up. The BME area was assessed using magnetic resonance imaging before treatment and at the 6-month follow-up.

RESULTS

Statistically significant improvements were observed in clinical scores and in the BME area for both the ESWT and the control group (p < 0.05). The improvements in the ESWT group were statistically better in all parameters compared with the control group: the ESWT group had a reduction in the BME area of 86% versus 41% in the control group, the VAS pain score improved by 88% in the ESWT group versus 42% in the control group, and the WOMAC score improved by 65% in the ESWT group versus 22% in the control group. Clinical scores were significantly better for patients with medial tibial lesions in the ESWT group.

CONCLUSION

In this study, ESWT reduced pain and the BME area in the knee, with significant clinical improvement noticed 3 months after treatment.

Osteonecrosis

Younger patients are affected more often by osteonecrosis than by osteoarthritis, and osteonecrosis has significantly greater long-term morbidity.

Corticosteroids are the most common cause of nontraumatic osteonecrosis.

The femoral head is the most common site of osteonecrosis.

In rare instances, osteonecrosis of the jaw has been associated with bisphosphonate exposure. This phenomenon is more common with repeated intravenous infusions of bisphosphonates.

Case reports of osteonecrosis of the jaw in association with other medications, such as denosumab, have been reported.

The final common pathway in the pathogenesis of osteonecrosis is disruption of blood supply to a segment of bone.

Abnormalities in lipid metabolism, bone homeostasis, regulation of apoptosis, coagulopathies, innate immunity, and oxidative stress may play a role in the pathogenesis of osteonecrosis.

Epigenetics may alter the predisposition to develop osteonecrosis.

MRI is currently the optimal test for early diagnosis and identification of the extent of osteonecrosis.

Nonsurgical treatment of osteonecrosis does not change the natural history of the disease.

Although surgical treatment of femoral head osteonecrosis has many variations, most symptomatic patients eventually require total hip arthroplasty.

Knowledge of risk factors and early detection are crucial to the successful management of osteonecrosis.

Because of the lack of successful treatment options, new modes of management focus on the prevention of osteonecrosis.

Bone Marrow Edema Syndrome in the Foot and Ankle

Bone marrow edema syndrome (BMES) is an uncommon and self-limited syndrome characterized by extremity pain of unknown etiology. Symptoms may include sudden or gradual onset of swelling and pain at rest or during activity, usually at night. This syndrome mostly affects middle-aged men and younger women who have pain in the lower extremities. The most common sites involved with BMES, in decreasing order of frequency, are the bones about the hip, knee, ankle, and foot. The diagnosis of BMES is confirmed with magnetic resonance imaging to exclude other causes of bone marrow edema. The correct diagnosis in the foot and ankle often is delayed because of the low prevalence and nonspecific signs. This delay may intensify bone pain and impair patient function and quality of life. The goal of BMES treatment is to relieve pain and shorten disease duration. Treatment options are limited and may include symptomatic treatment, pharmacologic treatment, and surgery.

LEVEL OF EVIDENCE

Level V, expert opinion.

Bone abnormalities of the knee: MRI features

The knee is one of the most studied anatomical structures by magnetic resonance imaging (MRI). Bone abnormalities are very frequently detected, whether or not related to the symptoms for which imaging was indicated. The aim of this pictorial study is to review the most commonly observed bone abnormalities of the knee, bearing in mind that the interpretation of MR images should always take into consideration both clinical and laboratory data, as well as the results of conventional X-ray imaging.

Extracorporeal shock wave therapy in the treatment of primary bone marrow edema syndrome of the knee: a prospective randomised controlled study

BACKGROUND

The aim of this prospective study was to evaluate the effectiveness of extracorporeal shock wave therapy (ESWT) in normalizing the symptoms and imaging features of primary bone marrow edema syndrome (BMES) of the knee.

METHODS

This study compared the outcomes of ESWT (Group A) (n = 20) and intravenously applied prostacyclin and bisphosphonate (Group B) (n = 20) in the treatment of BMES of the knee in our department between 2011 and 2013. The Visual Analog Scale for pain (VAS, 100 mm), the Western Ontario and McMaster University Osteoarthritis Index (WOMAC), the SF-36 scores and MRI scans as well as plain radiographs were obtained before and after therapy between two groups.

RESULTS

Compared with Group B, we found greater improvement in VAS, the WOMAC Osteoarthritis Index and SF-36 score at 1, 3 and 6 months post-treatment in Group A (P < 0.05). Furthermore, MRI scans showed a higher incidence of distinct reduction and complete regression of bone marrow edema at 6 months in Group A (95 vs. 65 %; P = 0.018). The MRI at 1 year follow-up showed complete regression in all patients in Group A. However, two cases in Group B continued to normalize over the subsequent follow-up period.

CONCLUSIONS

ESWT can produce rapid pain relief and functional improvement. It may be an effective, reliable, and non-invasive technique for rapid treatment of BMES of the knee.

TRIAL REGISTRATION

Research Registry UIN 528, September 03, 2015.

Treatment of bone marrow lesions (bone marrow edema)

Bone marrow lesions (BMLs) or using older terminology 'Bone marrow edema' is characterised by excessive water signals in the marrow space on magnetic resonance imaging or ultrasound; BMLs constitute a central component of a wide variety of inflammatory and non-inflammatory rheumatologic conditions affecting the musculoskeletal system: BMLs are not only considered significant sources of pain but also linked to increased disease activity in many musculoskeletal conditions (for example, osteoarthritis, rheumatoid arthritis). The purpose of this review is to summarise current knowledge about the treatment of BMLs, with an emphasis on the clinical and histological features of this entity in inflammatory and non-inflammatory disease. We also try to pair this hypothesis with the apparent beneficial effects of various treatment regimens, mainly within the group of bone antiresorptive drugs (calcitonin, bisphosphonates) on symptoms associated with BMLs.

Subchondral Calcium Phosphate is Ineffective for Bone Marrow Edema Lesions in Adults With Advanced Osteoarthritis

BACKGROUND

Injury to subchondral bone is associated with knee pain and osteoarthritis (OA). A percutaneous calcium phosphate injection is a novel approach in which subchondral bone marrow edema lesions are percutaneously injected with calcium phosphate. In theory, calcium phosphate provides structural support while it is gradually replaced by bone. However, little clinical evidence supports the efficacy of percutaneous calcium phosphate injections.

QUESTIONS/PURPOSES

We asked: (1) Does percutaneous calcium phosphate injection improve validated patient-reported outcome measures? (2) What proportion of patients experience failure of treatment (defined as a low score on the Tegner Lysholm Knee Scoring Scale)? (3) Is there a relationship between outcome and age, sex, BMI, and preoperative grade of OA?

METHODS

Between September 2012 and January 2014, we treated 33 patients with percutaneous calcium phosphate injections. Twenty-five satisfied our study inclusion criteria; of those, three patients were lost to followup and 22 (88%; 13 men, nine women) with a median age of 53.5 years (range, 38-70 years) were available for retrospective chart review and telephone evaluation at a minimum of 6 months (median, 12 months; range, 6-24 months). Our general indications for this procedure were the presence of subchondral bone marrow edema lesions observed on MR images involving weightbearing regions of the knee associated with localized pain on weightbearing and palpation and failure to respond to conservative therapy (> 3 months). Patients with pain secondary to extensive nondegenerative meniscal tears with a flipped displaced component at the level of bone marrow edema lesions, or with mechanical axis deviation greater than 8° were excluded. All patients had Grades III or IV chondral lesions (modified Outerbridge grading system for chondromalacia) overlying MRI-identified subchondral bone marrow edema lesions. Percutaneous calcium phosphate injection was performed on the medial tibial condyle (15 patients), the medial femoral condyle (five patients), and the lateral femoral condyle (two patients). Concomitant partial meniscectomy was performed in 18 patients. Preoperative and postoperative scores from the Knee Injury and Arthritis Outcome Score (KOOS) and the Tegner Lysholm Knee Scoring Scale were analyzed.

RESULTS

For patients available for followup, the outcome scores improved after treatment. The KOOS improved from a mean of 39.5 ± 21.8 to 71.3 ± 23 (95% CI, 18.6-45.2; p < 0.001) and the Tegner and Lysholm score from 48 ± 15.1 to 77.5 ± 20.6 (95% CI, 18.8-40.2; p < 0.001). However, seven of the 22 patients had poor clinical outcomes as assessed by the Tegner Lysholm Knee Scoring Scale, whereas three had fair results, five had good results, and seven had excellent results. The postoperative Tegner Lysholm score was inversely related to the preoperative Kellgren-Lawrence OA grade (R(2) = 0.292; F (1.20) = 9.645; p = 0.006). We found no relationship between outcome scores and age, sex, or BMI.

CONCLUSIONS

In a study that would have been expected to present a best-case analysis (short-term followup, loss to followup of patients with potentially unsatisfactory results, and use of invasive cotreatments including arthroscopic débridements), we found that percutaneous calcium phosphate injection in patients with symptomatic bone marrow edema lesions of the knee and advanced OA yielded poor results in a concerning proportion of our patients. Based on these results, we advise against the use of percutaneous calcium phosphate injections for patients with advanced osteoarthritic changes.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Progression and Treatment of Bilateral Knee Bone Marrow Edema Syndrome

CASE

We report the case of a patient with bilateral multicompartmental bone marrow edema syndrome of the knee, which responded favorably to subchondral core decompression after failing to respond to nonoperative treatment.

CONCLUSION

This case demonstrates that subchondral core decompression can be effective for the treatment of bone marrow edema syndrome.

Primary bone marrow oedema syndromes

MRI scanning in patients with rheumatological conditions often shows bone marrow oedema, which can be secondary to inflammatory, degenerative, infective or malignant conditions but can also be primary. The latter condition is of uncertain aetiology and it is also uncertain whether it represents a stage in the progression to osteonecrosis in some patients. Patients with primary bone marrow oedema usually have lower limb pain, commonly the hip, knee, ankle or feet. The diagnosis is one of exclusion with the presence of typical MRI findings. Treatment is usually conservative and includes analgesics and staying off the affected limb. The natural history is that of gradual resolution of symptoms over a number of months. Evidence for medical treatment is limited, but open-label studies suggest bisphosphonates may help in the resolution of pain and improve radiological findings. Surgical decompression is usually used as a last resort.

Osteonecrosis

Osteonecrosis affects younger patients more often than osteoarthritis and has significantly greater long-term morbidity.

Corticosteroids constitute the most common cause of nontraumatic osteonecrosis.

The femoral head is the most common site of osteonecrosis.

Bisphosphonate use is associated with osteonecrosis of the jaw.

The final common pathway in the pathogenesis of osteonecrosis is disruption of blood supply to a segment of bone.

Abnormalities in lipid metabolism, bone homeostasis, regulation of apoptosis, coagulopathies, and oxidative stress may play a role in the pathogenesis of osteonecrosis.

Magnetic resonance imaging is currently the optimal test for early diagnosis and identification of the extent of osteonecrosis.

Nonsurgical treatment of osteonecrosis does not change the natural history of the disease.

Although there are many variations on surgical treatment of femoral head osteonecrosis, most patients eventually require total hip arthroplasty.

Knowledge of risk factors and early detection are crucial to the successful management of osteonecrosis.

Due to the lack of successful treatment options, new modes focus on prevention of osteonecrosis.

Treatment for painful bone marrow edema by open wedge tibial osteotomy

We evaluated the results of patients who had undergone medial open wedge proximal tibial osteotomy, with painful bone marrow edema in the medial tibial plateau. The study included 21 patients who had presented with knee pain and whose MRIs showed bone marrow edema in medial plateau. The degree of osteoarthritis was evaluated radiologically according to the Kellgren-Lawrence criteria; 6 cases were Grade 1, 11 cases were Grade 2, and 3 cases were Grade 3. Preoperative varus angle was a mean of 2.19° (0-4). The bone marrow edema was classified according to the width of the lesions extending into the joint surface subchondral area on MRI T2 sequences. Open wedge osteotomy was performed in all patients. The postoperative results were evaluated by X-ray, MRI, and WOMAC (Western Ontario and McMaster Universities) knee scores. The preoperative 2.19° varus angle was evaluated postoperatively as valgus 6.57° (4-8°) (p < 0.05). The postoperative WOMAC knee scores revealed a significant decrease in pain (p < 0.05). In conclusion, we are of the opinion that medial open wedge proximal tibial osteotomy is an effective treatment in patients who have painful bone marrow edema in medial tibia plateau.

Bone marrow lesions: a universal bone response to injury?

The ever increasing use of magnetic resonance imaging in clinical practice has led to the recognition of a new entity, bone marrow lesions (BMLs). These lesions are characterized by excessive water signals in the marrow space and have emerged as a central component of many different diseases affecting the musculoskeletal system. BMLs have in particular been associated with a wide variety of inflammatory and non-inflammatory rheumatologic conditions and are not only considered significant sources of pain, but also linked to the worsening of patient prognosis in many disease states. In this review, we summarize the current knowledge on BMLs with an emphasis on the clinical and histological features of this entity in inflammatory and non-inflammatory disease and provide a unifying hypothesis based on the appearance with various imaging technologies. We also try to pair this hypothesis with the apparent beneficial effects of various treatment regimens, mainly within the group of bone antiresorptive drugs (calcitonin, bisphosphonates) on symptoms associated with BMLs.

Transient osteoporosis associated with pregnancy: use of bisphosphonate in treating a lactating mother

Transient osteoporosis is a rare condition causing regional pain, immobility and functional compromise. The authors present the case of a pregnant lady with multiple sites of transient osteoporosis, including a stress fracture, successfully treated with intravenous pamidronate and a physical rehabilitation programme. The authors discuss the mechanisms for the syndrome and its overlap with complex regional pain syndrome type I; as well as the implications of bisphosphonate administration to a nursing mother. The authors also highlight the advantages of MRI over standard radiography when investigating unexplained foot pain.

Possible beneficial effect of bisphosphonates in osteonecrosis of the knee

Osteonecrosis (ON) in the knee occurs as a localized inflammatory disease in relation to spontaneous or non-traumatic ON. Conservative treatment possibilities are limited, and prognosis appears to be poor; in most cases, ON results in knee arthroplasty. Bisphosphonates are suggested to prevent bone resorption and collapse of necrotic bone. In this observational, prospective study we investigated the effect of bisphosphonate treatment in patients with spontaneous or arthroscopy-induced ON of the knee. Twenty-eight patients with osteonecrotic lesions and bone marrow oedema in the knee were included. In 22 patients (80%), ON was identified after arthroscopic surgery of the knee; six patients were diagnosed with spontaneous ON. Patients were initially given pamidronate 120 mg i.v. divided in 3-4 perfusions over 2 weeks, followed by oral bisphosphonate treatment with alendronate 70 mg weekly for 4-6 months. Bisphosphonate treatment resulted in a rapid pain relief, VAS decreasing from 8.2 ± 1.2 at baseline to 5.02 ± 0.6 after 4-6 weeks (p < 0.001). After 6 months, the VAS decreased by 80% (p < 0.001). At the 6-month follow-up, symptoms had resolved completely in 15 patients out of 28; in 6 patients, minimal symptoms (VAS 1-2) remained. In two patients, treatment effect was unsatisfactory, and surgical intervention was needed (arthroplasty). Bone marrow oedema on MRI resolved completely in 18 patients out of 28 with substantial reduction in the remaining. Furthermore, osteonecrotic area resolved completely or demarcation with sclerotic changes of the necrotic area could be observed. Bisphosphonate treatment in patients with osteonecrosis of the knee was associated with a rapid improvement in pain score and radiological consolidation of the area of osteonecrosis. Further randomized, controlled trials are warranted to confirm the potential beneficial role of bisphosphonates in the treatment of osteonecrosis of the knee.

LEVEL OF EVIDENCE

observational study, level IV.

Bilateral transient bone marrow edema or transient osteoporosis of the knee in pregnancy

Transient osteoporosis or transient bone marrow edema is an uncommon self-limiting condition of unknown etiology. The most commonly affected joint is the hip, followed by the knee, ankle, and the foot. Simultaneous involvement of both hips has been reported exclusively in pregnant women. Bilateral knee involvement during pregnancy seems to be extremely rare. We present a case of bilateral transient bone marrow knee edema during pregnancy with complete resolution of symptoms and radiological findings after 10 months.

Acute nontraumatic adult knee pain: the role of MR imaging

Acute nontraumatic pain in the adult knee can be seen in many settings, such as transient bone marrow oedema syndrome (TBMOS), regional migratory osteoporosis (RMO), spontaneous osteonecrosis (SONK) and insufficiency fractures. Early differentiation among them is crucial to avoid unnecessary treatment. TBMOS and RMO are considered to be self-limiting conditions without longterm sequelae. On the other hand, the clinical course of SONK is thought to be dependent on the size of osteonecrosis. Recent data suggest the term SONK is misleading one and should be replaced. Insufficiency fractures may demonstrate a similar clinical syndrome without a history of a single traumatic injury. The imaging pathway for knee pain has evolved considerably with the advent of magnetic resonance (MR) imaging, which is very sensitive in the early depiction of bone marrow oedema. Therefore, in patients with acute nontraumatic knee pain whose radiographs are negative or inconclusive, MR imaging is the method of choice for further evaluation. This article discusses the potential aetiologies and reviews MR imaging findings of the most common disorders afflicting the subchondral knee-joint area.

Regional migratory osteoporosis in a patient with ankylosing spondylitis

We report the first case of regional migratory osteoporosis (RMO) in a patient with ankylosing spondylitis (AS). This middle-aged man suffered from an acute onset of knee pain that increased on weight bearing, followed by ankle pain. The diagnosis of RMO was confirmed using magnetic resonance imaging (MRI), after exclusion of other causes of knee pain. MRI revealed a large area of bone marrow oedema without a zone of demarcation or subchondral fracture with a demonstration of shifting marrow oedema on the follow-up MRI scan from the medial femur condyl to the tibia plateau lateral and then to the distal tibia epiphysis. Treatment with the bisphosphonate ibandronate, however, was unsuccessful. RMO is characterized clinically by migrating arthralgia of the weight-bearing joints of the lower limbs, mainly in middle-aged males. Although the aetiology is unknown, the pathophysiology of RMO seems to be closely related to transient osteoporosis of the hip (TOH), which has been considered a reversible stage of avascular necrosis of the hip (AVN). There is no causal treatment for RMO. Avoidance of weight bearing and use of analgesics are effective in reducing symptoms. The combination of RMO and AS yielded diagnostic difficulties, as the clinical picture and the marrow oedema seen on MRI could be attributed to several AS-related causes such as enthesitis, early stadium of arthritis, osteonecrosis, or sterile osteomyelitis.

Transient osteoporosis of the knee

A 52-year-old man presented with a 3-week history of right knee pain, significant enough to prevent weight bearing. There was no history of knee injury or disease. On knee examination, an effusion and medial joint line tenderness was noted. Knee range of motion was full, but painful. Radiographs revealed minor osteoarthritic changes. Laboratory values were within normal limits, including those associated with infection. Magnetic resonance imaging showed decreased signal intensity on T1-weighted images within the medial femoral condyle and corresponding increased signal intensity on T2-weighted consistent with bone marrow edema as well as edema to the adjacent soft tissues. Bone scanning showed increased uptake of radioisotope in the medial femoral condyle. The patient was diagnosed with bone marrow edema syndrome, and managed medically with analgesics and continued non weight-bearing status. At the 1-month follow-up, his symptoms had improved significantly. The patient progressively increased weight bearing as tolerated over the subsequent weeks. At 12-week follow-up, symptoms had completely resolved. Magnetic resonance imaging showed no signal abnormalities in the affected knee. Transient osteoporosis is an uncommon and typically self-limiting condition that can be challenging to diagnose and treat. The clinician must be aware of this entity, as well as its typical course, to prevent unnecessary testing and invasive intervention.

Regional migratory osteoporosis in the knee: MRI findings in 22 patients and review of the literature

OBJECTIVE

Acute non-traumatic bone marrow edema (BME) in the knee is a common clinical problem. The aim of the present study is to present the MR imaging findings of the uncommon transient migratory pattern of this syndrome.

MATERIALS AND METHODS

Twenty-two patients (21 men, 1 woman, age range 35-73 years, mean 49.4+/-7.6) who presented with pain in the knee joint (ranging from 2 weeks to 6 months) and BME in the MR imaging examination, were included in the study. In all cases, the knee joint BME was either preceded or followed by another site of BME in the same or another joint. All patients were studied with plain X-rays and MR imaging at presentation and with MR imaging after resolution of symptoms.

RESULTS

The eight patients with initial involvement in the knee showed migration either intra-articularly (5), or/and in the contralateral knee (2) and only 1 case showed migration to the ipsilateral hip joint. In two patients the BME shifted from the hip first to the foot and then to the knee. The median migration period was 4 months for the second involvement in all patients and 3 months for the third involvement (10 patients).

CONCLUSIONS

The present study reports the largest series of patients with regional migratory osteoporosis involving the knee. In most of the cases, shifting of BME remains in the joint or moves to the contralateral knee. In only one case the BME shifted from the knee elsewhere. All lesions were transient.

Acute non-traumatic marrow edema syndrome in the knee: MRI findings at presentation, correlation with spinal DEXA and outcome

PURPOSE

The aim of the study was to present the MRI findings of non-traumatic edema-like lesions presented acutely in the adult knee and to correlate them with the 3-year outcome and the bone mineral density (BMD) in the spine.

MATERIALS AND METHODS

Ninety-eight patients (40 men, 58 women, mean age 60.1+/-11 years, age range 27-82 years), were followed up clinically as well as with MR imaging, when indicated, for at least 3 years. Patients were classified according to presentation in 3 groups (A: bone marrow edema (BME), B: BME and subchondral fracture, C: BME and articular collapse) and according to outcome in 2 groups (A: reversible BME, B: articular collapse). BMD measurements of the spine were carried out in males over 70 and females over 60 years old using DEXA.

RESULTS

The isolated BME pattern was observed in 64.3% (Group A), subchondral fractures without articular collapse in 11.2% (Group B) and articular collapse in 24.5% (Group C). Significant differences were found among the 3 groups at presentation, regarding the age, sex, BMD, affected area and duration of symptoms prior to imaging (p<0.05). Localization of the lesions in the weight-bearing areas of the knee was shown in 100% of C, in 90.9% of B and in 50.8% of A. The duration of symptoms prior to imaging was longer in C (7.6+/-2.8m) than in A (2.5+/-1.7m) and B (4.0+/-3.2m) (p<0.05). Group B progressed to articular collapse in 45.5%, the rest demonstrating a favourable outcome. Group C showed clinical improvement in 75% and persistent symptoms that required knee arthroplasty in 25% of cases. Articular collapse was the final outcome in 29.6% and transient BME in 70.4% of patients. These two groups showed significant differences regarding the age (p approximately 0), sex (p=0.002), low BMD (p=0.004), affected area (p approximately 0), presence of subchondral sparing (p approximately 0), duration of symptoms prior to imaging (p approximately 0), time from onset of symptoms to the final outcome (p approximately 0) and need for arthroplasty (p=0.001). None of the patients with transient BME syndrome eventually progressed to articular collapse.

CONCLUSION

In the context of acute non-traumatic knee BME, the age and sex of the patient, the duration of symptoms before imaging, the pattern of BME, and the BMD appear to correlate with the final outcome.

Magnetic resonance imaging of subarticular bone marrow lesions in dogs with stifle lameness

A bone bruise is a magnetic resonance (MR) imaging sign thought to signify acute traumatic microfracture of trabecular bone with hemorrhage and edema in the marrow that may occur without grossly visible disruption of the adjacent cortices or overlying cartilage. In approximately 75% of people with acute anterior-cruciate ligament tears, bone bruises are detected in characteristic locations within the femur and tibia and are best seen as high-signal lesions using fat-suppression sequences. We questioned whether this is a component of naturally acquired stifle lameness in dogs and obtained short-tau inversion recovery (STIR) images of six dogs with stifle lameness. High-signal STIR lesions were detected in five of six (83%) dogs and eight of 12 (67%) limbs. We observed these lesions deep to the intercondylar fossa of the femur and intercondylar eminence of the tibia, which are atypical locations in people. High-signal STIR lesions were detected in dogs with only synovitis, partial tear of the cranial cruciate ligament (CCL) and complete tear of the CCL. One of these lesions was seen in the lateral tibial condyle, a typical location in humans with acute anterior cruciate ligament tear. As the MR imaging appearance of stress fractures and bone bruises are similar, and the high-signal STIR lesions are at attachment sites of the CCL, this finding may be due to stress disease or other unknown causes, rather than bone bruising. High-signal STIR lesions may be a common sign in naturally acquired canine stifle disease, but the pathogenesis, prognostic and diagnostic values need further investigation.

Postarthroscopic osteonecrosis of the knee

Little is known about the etiology of postarthroscopic osteonecrosis of the knee. Its prevalence is probably very low. The most important differential diagnosis is pre-existing and undiagnosed early-stage spontaneous osteonecrosis of the knee. From the medicolegal point of view, orthopaedic surgeons need to be aware of the diagnostic pitfalls in differentiating between postarthroscopic osteonecrosis of the knee and spontaneous osteonecrosis of the knee, and they must understand that both may be unpreventable conditions. The purpose of this report is to review the presumable pathophysiology and the clinical and radiographic features as well as the pitfalls in diagnosing postarthroscopic osteonecrosis of the knee.