Treatment of spontaneous osteonecrosis of the knee (SPONK) by a bisphosphonate

A Current Review in the Orthopedic Management of Osteonecrosis of the knee Secondary to Treatment of Pediatric Hematologic Malignancy

Acute Lymphoblastic Leukemia is the most prevalent pediatric hematologic malignancy. The treatment for this illness has advanced significantly, now touting a 90% cure rate. Although these patients often become disease free, treatment can leave devastating effects that last long after their disease burden is alleviated. A commonly experienced result of treatment is osteonecrosis (ON), often occurring in weight bearing joints. Uncertainty exists in the optimal treatment of this cohort of patients. In this review, we describe the etiology and suspected pathogenesis of ON, as well as treatment options described in the literature.

Spontaneous Osteonecrosis of the Knee: State of the Art

Osteonecrosis is a terrible condition that can cause advanced arthritis in a number of joints, including the knee. The three types of osteonecrosis that can affect the knee are secondary, post-arthroscopic, and spontaneous osteonecrosis of the knee (SPONK). Regardless of osteonecrosis classification, treatment for this condition seeks to prevent further development or postpone the onset of knee end-stage arthritis. Joint arthroplasty is the best course of action whenever there is significant joint surface collapse or there are signs of degenerative arthritis. The non-operative options for treatment at the moment include observation, nonsteroidal anti-inflammatory medications (NSAIDs), protective weight bearing, and analgesia if needed. Depending on the severity and type of the condition, operational procedures may include unilateral knee arthroplasty (UKA), total knee arthroplasty (TKA), or joint preservation surgery. Joint preservation techniques, such as arthroscopy, core decompression, osteochondral autograft, and bone grafting, are frequently used in precollapse and some postcollapse lesions, when the articular cartilage is typically unaffected and only the underlying subchondral bone is affected. In contrast, operations that try to save the joint following significant subchondral collapse are rarely successful and joint replacement is required to ease discomfort. This article's goal is to summarise the most recent research on evaluations, clinical examinations, imaging and various therapeutic strategies for osteonecrosis of the knee, including lesion surveillance, medicines, joint preservation methods, and total joint arthroplasty.

[Drug treatment of osteonecrosis]

The medicinal treatment of osteonecrosis is described as part of the conservative treatment for atraumatic femoral head necrosis of the hip in adults and for Ahlbäck's disease of the knee joint. For femoral head necrosis, iloprost is used in the early stages (ARCO I and II) as a treatment attempt to eliminate pain and the accompanying bone marrow edema. This also applies to the use of bisphosphonates, whereby preferably small defects (< 30%) are suitable for treatment. Bisphosphonates are successfully used in the knee joint to treat Ahlbäck's disease, although the results are sometimes contradictory. Other locations, such as the humeral head, talus, scaphoid, lunate, proximal tibia, and metatarsal head, are sometimes successfully treated with bisphosphonates. Although the results seem promising, the groups are far too small to derive treatment recommendations in this regard.

Osteonecrosis of the Knee: Not all Bone Edema is the Same

Knee pain is among the most common complaints that an orthopedic surgeon may see in practice. It is often worked up with X-rays and MRI, leading to a myriad of potential diagnoses ranging from minimal edema patterns to various types of osteonecrosis. Similarities in certain causes can pose diagnostic challenges. The purpose of this review was to present the 3 types of osteonecrosis observed in the knee as well as additional causes to consider to help aid in the diagnosis and treatment..

A Case of Subchondral Insufficiency Fracture of the Knee at Lateral Femoral Condyle Treated With Unicompartmental Knee Arthroplasty

Spontaneous insufficiency fracture of the knee is a potentially devastating yet poorly understood disease entity that can lead to secondary osteoarthritis. Most cases involve the medial femoral condyle, and the lateral femoral condyle is rarely affected. The optimal treatment for spontaneous insufficiency fracture of the lateral femoral condyle remains undetermined, and there are no previous dedicated reports on treatment outcome with unicompartmental knee arthroplasty. A middle-aged lady presented with subacute left knee pain and a locked knee. Subsequent imaging studies revealed a spontaneous insufficiency fracture of the lateral femoral condyle. In view of the isolated compartment involvement, unicompartmental knee arthroplasty was performed with satisfactory outcome. At 1 year postoperatively, the patient had complete resolution of knee pain and was able to resume working.

Secondary osteonecrosis of the knee as a part of long COVID-19 syndrome: a case series

COVID-19 infection affects different organ systems with long-term sequelae, which has been termed as long COVID-19 syndrome. To the best of our knowledge, osteonecrosis of the knee as a part of long COVID-19 syndrome has not been documented. Corticosteroids are being used extensively in moderate and severe cases of COVID-19. We report two cases who developed osteonecrosis of the knee after being treated for COVID-19 infection. In our case series, the mean cumulative dose of prednisolone was 1156.5 mg (900-1413 mg), which is less than the cumulative dose reported in literature for osteonecrosis of the knee. In our case series, the patients developed symptomatic osteonecrosis at a mean interval of 73 days after initiation of steroid therapy, with the earliest presenting at 25 days. Early diagnosis of osteonecrosis of the knee on high clinical suspicion by MRI would help in early intervention with bisphosphonate therapy.

Effects of Korean Traditional Medicine Treatment on Spontaneous Osteonecrosis of the Knee: A Case Report

Spontaneous osteonecrosis of the knee (SONK) is a common form of osteonecrosis of the knee and mainly affects the medial condyle due to localized vascular insufficiency. We report a case of SONK in a 65-year-old woman who had severe knee pain in her left knee whichimpeded her capacityto walk beyond 10 minutes. Bilateral knee X-rays revealed degenerative osteoarthritis of both knees and magnetic resonance imaging revealed R/O SONK in the lateral aspect of the medial femoral condyle, as well as a medial meniscal posterior horn root tear, and a Grade 1 medial collateral ligament injury. She was hospitalized at Jaseng Hospital of Korean Medicine for 21 days and receivedcombination therapy includingacupuncture, pharmacopuncture, and herbal medicine. Patient-reported scales indicated that her pain and physical functional limitations were alleviated. Combination therapy consisting of Korean traditional medicine may bean alternative non-operative treatment approach for patients with SONK.

Bisphosphonate Therapy for Treating Osteonecrosis in Pediatric Leukemia Patients: A Systematic Review

BACKGROUND

Despite improved outcomes in children with leukemia, complications such as osteonecrosis are common. We conducted a systematic review to investigate the role of bisphosphonates in reducing pain, improving mobility, and stabilizing lesions in pediatric leukemia survivors.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched the PubMed, Embase, Cochrane, Web of Science, Scopus, CINAHL, and ClinicalTrials.gov databases. Five of 221 articles retrieved met our inclusion criteria.

RESULTS

Bisphosphonates, especially when combined with dietary calcium and vitamin D supplements and physical therapy (supplements/PT) were associated with improved pain and mobility in 54% and 50% of patients, respectively. A significantly greater proportion of patients treated with bisphosphonates (83%) reported mild/moderate pain or no pain compared with those with supplements/PT alone (36%) (P<0.001). Sixty-six percent of patients treated with bisphosphonates achieved improved/full mobility compared with 27% of those treated with supplements/PT alone (P=0.02). However, 46% of patients showed progressive joint destruction despite bisphosphonate therapy. No adverse events were reported, except for acute phase reactions to intravenous therapies.

CONCLUSIONS

Bisphosphonates, when combined with supplements/PT, were associated with less pain and improved mobility, but not prevention of joint destruction in pediatric leukemia patients with osteonecrosis.

Bisphosphonate for spontaneous osteonecrosis of the knee: A protocol for systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Bisphosphonates are commonly used to treat spontaneous osteonecrosis of the knee (SONK), while there are no relevant systematic review or meta-analysis designed to evaluate the effects of bisphosphonates on SONK.

METHODS

We will identify relevant randomized controlled trials from the PubMed, EMBASE, CINAHL and China National Knowledge Infrastructure, up to March 20, 2020. Data that meets the inclusion criteria will be extracted and analyzed using RevMan V.5.3 software. Two reviewers will assess quality of the included studies by using the Cochrane Collaboration risk of bias tool. Egger test and Begg test will be used to evaluate publication bias. And Grading of Recommendations Assessment, Development and Evaluation will be employed to assess the quality of evidence.

RESULTS

In this study, we will analyze the effect of bisphosphonates on pain intensity, physical function, biochemical including alkaline phosphatase, N-terminal propeptide of type I procollagen, and C-terminal type I collagen telopeptide, radiological outcome (evaluated by using Magnetic resonance imaging) and ratio of secondary surgery for patients with SONK.

CONCLUSION

Our findings will provide evidence for the effectiveness and potential treatment prescriptions of bisphosphonates acupuncture for patients affected by SONK.

Effect of Zoledronic Acid and Alendronate on Bone Edema and Pain in Spontaneous Osteonecrosis of the Knee: A New Paradigm in the Medical Management

Objective  The aim of the present study was to determine the effect of combined zoledronic acid and alendronate therapy on bone edema and knee pain in cases of spontaneous osteonecrosis of the knee. We report our experience with this treatment.

Methods  A retrospective case series of 11 patients with spontaneous osteonecrosis of the knee confirmed by magnetic resonance image (MRI). The patients were treated with a single dose of 5 mg of intravenous zoledronic acid combined with 35 mg twice a week of oral alendronate, for 16 weeks. The visual analogue scale scores were noted before the beginning of the therapy, at 8 weeks, and at 16 weeks of follow-up. The size of the bone marrow edema adjacent to the lesion was measured on T2-weighted MRI coronal images at the beginning of the therapy and at 16 weeks.

Results  The average visual analogue scale score at 0 weeks was of 7.72, and of 0.81 at 16 weeks of therapy; the difference was statistically significant ( p  = 0.03). The mean bone marrow involvement at 0 weeks was of 80%, which reduced to 11.81% at 16 weeks of therapy. This change was statistically significant ( p  = 0.03).

Conclusion  Our data shows that the combination therapy causes early pain relief and reduction of the bone edema, and it is safe, effective and well-tolerated for a painful disease entity like spontaneous osteonecrosis of the knee.

The SIFK score: a validated predictive model for arthroplasty progression after subchondral insufficiency fractures of the knee

PURPOSE

The purpose of this study was to create a predictive model utilizing baseline demographic and radiographic characteristics for the likelihood that a patient with subchondral insufficiency fracture of the knee will progress to knee arthroplasty with emphasis on clinical interpretability and usability.

METHODS

A retrospective review of baseline and final radiographs in addition to MRIs were reviewed for evaluation of insufficiency fractures and associated injuries. Patient and radiographic factors were used in building predictive models for progression to arthroplasty with Train: Validation: Test subsets. Multiple models were compared with emphasis on clinical utility.

RESULTS

Total of 249 patients with a mean age of 64.6 (SD 10.5) years were included. Knee arthroplasty rate was 27% at mean of 4 years of follow-up. Lasso Regression was non-inferior to other models and was chosen for ease of interpretability. In order of importance, predictors for progression to arthroplasty included lateral meniscus extrusion, Kellgren-Lawrence Grade 4, SIFK on MFC, lateral meniscus root tear, and medial meniscus extrusion. The final SIFK Score stratified patients into low-, medium-, and high-risk categories with arthroplasty rates of 8.8%, 40.4%, and 78.9% (p < 0.001) and an area under the curve of 82.5%.

CONCLUSION

In this validated model, lateral meniscus extrusion, K-L Grade 4, SIFK on MFC, lateral meniscus root tear, and medial meniscus extrusion were the most important factors in predicting progression to arthroplasty (in that order). This model assists in patient treatment and counseling in providing prognostic information based on patient-specific risk factors by classifying them into a low-, medium-, and high-risk categories. This model can be used both by medical professionals treating musculoskeletal injuries in guiding patient decision making.

LEVEL OF EVIDENCE

Level III.

Spontaneous Osteonecrosis/Subchondral Insufficiency Fractures of the Knee: High Rates of Conversion to Surgical Treatment and Arthroplasty

BACKGROUND

Spontaneous osteonecrosis of the knee has recently been termed subchondral insufficiency fracture of the knee (SIFK) to appropriately recognize the etiology of mechanical overloading of the subchondral bone. The purpose of this study was to assess clinical outcomes of SIFK based on progression to surgical treatment and arthroplasty, and to evaluate the risk factors that increase the progression to arthroplasty.

METHODS

A retrospective review was performed on patients with a diagnosis of SIFK, as confirmed with use of magnetic resonance images (MRIs). Baseline and final radiographs were reviewed. Baseline MRIs were also reviewed for injury characteristics. Failure was defined as progression to surgical treatment or conversion to arthroplasty.

RESULTS

Two hundred twenty-three patients (71% female) with a mean age of 65.1 years were included. SIFK affected 154 femora (69%) and 123 tibiae (55%), with medial compartment involvement in 198 knees (89%); 74% of medial menisci had root or radial tears, with a mean extrusion of 3.6 mm. Varus malalignment was identified in 54 (69%) of 78 knees. Seventy-six (34%) of all patients progressed to surgical intervention at 2.7 years, and 66 (30%) underwent arthroplasty at 3.0 years. The rates of conversion to surgical intervention and arthroplasty increased to 47% (37 of 79; p = 0.04) and 37% (29 of 79; p = 0.09), respectively, in patients with >5 years of follow-up. The 10-year survival rate free of arthroplasty for patients with SIFK on the medial femoral condyle (p < 0.01), SIFK on the medial tibial plateau (p < 0.01), medial meniscal extrusion (p = 0.01), varus alignment (p = 0.02), and older age (per year older; p = 0.003) was significantly higher than the survival rates of those without each respective condition.

CONCLUSIONS

Subchondral insufficiency fractures predominantly involve the medial compartment of the knee and commonly present with medial meniscal root and radial tears. Approximately one-third of patients progressed to total knee arthroplasty. Baseline arthritis, older age, location of the insufficiency fracture on both the medial femoral condyle and medial tibial plateau, meniscal extrusion, and varus malalignment were all associated with progression to arthroplasty.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Alternate treatment approach to subchondral insufficiency fracture of the knee utilizing genicular nerve cooled radiofrequency ablation and adjunctive bisphosphonate supplementation: A case report

Subchondral insufficiency fractures of the knee are commonly misdiagnosed fractures that are both very painful and difficult to treat. A conservative treatment modality to control symptoms during rehabilitation has not previously been described. This case report presents the alternate use of cooled radiofrequency ablation technique of the genicular nerves for pain relief and bisphosphonate infusion to address the underlying poor bone mineralization/density with imaging follow-up before and after instituted treatments. A middle-aged female patient presenting with atraumatic pain in the medial aspect of the left knee diagnosed on an original magnetic resonance imaging as an insufficiency fracture and debilitating pain. Multiple-surgeon opinions of total knee arthroplasty were not a consideration the patient wanted or could consider given her lifestyle. Cooled radiofrequency ablation of the genicular nerve branches was performed with significant-complete pain relief achieved that lasted at least 6 months. Bisphosphonate infusions were instituted to address the underlying osteoporosis detected by a dual energy X-ray absorptiometry (DEXA) scan. Clinical performance after the radiofrequency ablations was followed with clinically validated surveys (The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)/Knee Injury and Osteoarthritis Outcome Score (KOOS)) at 2 weeks, 1, 3, and 6 months. Patient was also asked to follow a restricted-modified weight-bearing plan for 3 months followed by physical therapy. Eight weeks apart of bisphosphonate infusions were delivered after proper administration of vitamin D. There was resolution of the insufficiency fracture at the medial femoral condyle between the magnetic resonance imaging exams within 4.5 months apart treated with restricted weight-bearing regimen. Pain resolution, significant improved function, and range of motion were the end results of our instituted treatment plan. This case reports presents an alternate pathway for the treatment of this condition especially when there is lack of consensus among physicians in how to best address this condition.

Spontaneous osteonecrosis of the knee: what do we know so far? A literature review

PURPOSE

Spontaneous osteonecrosis of the knee (SONK) is said to be a relatively common disease which may lead to an end-stage osteoarthritis of the knee. The aim of this paper was to review the literature on this field published until now, discuss the results of both conservative and surgical treatment options, as well as to introduce new methods of treatment, which may be applicable in SONK treatment.

METHODS

We searched the PubMed and Cochrane databases until November 2019 and presented the most recent findings in this work.

RESULTS

The exact aetiology of SONK still remains unclear; however, recent studies suggested that early stage of SONK is rather a result of the subchondral fracture than primary osteonecrosis. So far described conservative treatment includes non-weight bearing or protected weight bearing with a knee brace, nonsteroidal anti-inflammatory drugs, analgesics, and bisphosphonates. Surgical management includes arthroscopic debridement, core decompression, osteochondral autograft, high tibial osteotomy, and unicompartmental knee arthroplasty or total knee arthroplasty.

CONCLUSIONS

Although the aetiology of SONK remains unknown, there are many treatment options, and the choice of the most suitable one is challenging. We think that subchondroplasty may be one of the effective methods.

Treatment of spontaneous osteonecrosis of the knee by daily teriparatide: A report of 3 cases

RATIONALE

Although the treatment of femoral head necrosis has already been established with the adoption of daily teriparatide, a clear consensus on the treatment of spontaneous osteonecrosis of the knee (SONK) has yet to be reached. Therefore, we focused on the treatment of SONK with daily teriparatide administration (20 μg, subcutaneous) and confirmed its effects to determine whether it is a valid option.

PATIENTS' CONCERNS

Three osteoporotic patients who were diagnosed with SONK complained of knee pain.

DIAGNOSIS

SONK was diagnosed on magnetic resonance imaging in all cases.

INTERVENTIONS

All patients took daily teriparatide as a treatment for SONK.

OUTCOMES

There was a significant and dramatic reduction in the visual analog scale score 1 month after treatment. After 6 months of treatment, the sizes of the affected SONK lesions were smaller than in the initial phase, and plain X-rays showed no further signs of progression.

LESSONS

Daily teriparatide might be an effective treatment for SONK.

Medium-term clinical results of unicompartmental knee arthroplasty for the treatment for spontaneous osteonecrosis of the knee with four to 15 years of follow-up

BACKGROUND

Unicompartmental knee arthroplasty (UKA) is an option for the treatment of spontaneous osteonecrosis of the knee (SONK). However, there are limited studies focusing on this area. This study presents medium-term clinical outcome data of UKA for SONK.

METHODS

We reviewed 50 SONK knees in 48 patients that were treated by UKA. The mean age, height, and body weight were 73 years, 153 cm, and 57 kg, respectively. The mean follow-up was 8.4 years (range, four to 15 years). Preoperatively, we measured the size and the volume (estimated by width × length × depth) of the necrotic bone mass on T1-weighted magnetic resonance imaging. The clinical results were evaluated serially at follow-up visits radiographically and with the Knee Society Scoring (KSS) and Oxford Knee Scoring (OKS) systems.

RESULTS

There were no revisions, re-operations, or major complications. The mean sizes of the necrotic lesions were 17.2 mm (14.7-22.3 mm) in width, 28.2 mm (6.2-34.7 mm) in length, and 11.3 mm (3.2-14.5 mm) in depth. The mean volume was approximately 5.4 cm³ (0.7-10.3 cm³). The mean flexion of the knee, KSS Knee Score, Function Score, and OKS increased from a preoperative 128.7-137.5°, 52.3-91.3, 39.7-90.2, and 21.6-40.2, respectively, at the latest follow-up. At the last follow-up, all patients had good or excellent OKS.

CONCLUSIONS

This study demonstrates that UKA is a good option and is reliable for the treatment of SONK irrespective of necrotic bone mass size.

Characteristics, management, and outcomes of spontaneous osteonecrosis of the knee in Indian population

PURPOSE

Spontaneous osteonecrosis of the knee affects the medial femoral condyle in patients above 55 years of age. Many reports and studies are available from western countries. But there is a gross paucity of literature on spontaneous osteonecrosis of the knee (SPONK) in the Indian subcontinent, either it is under-reported or detected at a later stage. The aim of our study was to detect SPONK in Indian population and describe its characteristics, treatment, and outcome.

MATERIAL AND METHOD

A prospective study was conducted over a period of three years. All patients above 18 years with knee pain at rest and medial condyle tenderness without joint laxity were evaluated with plain radiographs and MRI. Further tests were done if radiological signs of osteonecrosis were present. Various parameters were recoded like Visual Analog Scale (VAS), Knee Society Score (KSS), and MRI Osteoarthritis Knee Score. Conservative treatment consisted of a combination of NSAIDs and bisphosphonates. Decompression with bone grafting was done if there was no improvement or deterioration at three month follow-up.

RESULTS

Ten patients were diagnosed with SPONK. The mean age was 50 years with male predominance (60%) with the involvement of medial femoral condyle (80%) or left knee (70%). Most cases were in Koshino stage 1. Mean VAS was 6.5 and mean KSS was 59. All clinical parameters showed improvement at one year.

DISCUSSION

A study with a bigger sample size and longer follow-up is needed to fill the lacunae of literature on this topic from the Indian subcontinent. In spite of the limitations, we did observe that in our population, males were more commonly affected than females, which is contrary to most studies on the subject. Also, the disease had an early age of onset (50 years) in Indian population as compared to Western and East Asian populations.

CONCLUSION

Combined therapy of NSAIDs and bisphosphonates shows excellent results over a period of one year. Joint-preserving surgeries are effective even in Koshino stage 3 SPONK.

Postarthroscopy Osteonecrosis of the Knee: Current Concepts

Knee osteonecrosis is a severe disease rapidly leading to end-stage osteoarthritis, which was classified into three categories: spontaneous, secondary, and postarthroscopy. To understand postarthroscopy osteonecrosis of the knee, all the three types of knee osteonecrosis have to be deepened. This article reviewed spontaneous and secondary osteonecroses of the knee, with special focus upon postarthroscopy osteonecrosis, which is a rare form, affecting patients operated for arthroscopic knee surgery, most commonly for meniscectomy. Due to its rarity, patients and surgeons are often unprepared for this complication. A correct diagnosis is essential for appropriate treatment, and also to determine if a preexisting osteonecrosis was present, avoiding medicolegal sequelae, although many authors agree that osteonecrosis (both spontaneous and postarthroscopy) represent unpreventable and unpredictable conditions. In spontaneous osteonecrosis, the treatment is defined according to the size and the degree of the lesion, whereas in postarthroscopy osteonecrosis, the size of the lesion has no prognostic value, and therefore, the choice of the correct treatment is based more on the timing of the diagnosis. A diagnostic and therapeutic algorithm was outlined on the basis of the actual knowledge.

Diseases of Subchondral Bone 2

Osteonecrosis of the knee can be divided into the following 3 categories: primary or Spontaneous osteonecrosis of the knee (SONK), secondary osteonecrosis (ON), and postarthroscopic osteonecrosis. Patient characteristics as well as underlying risk factors can help categorize the type of osteonecrosis and guide treatment. SONK was &filig;rst described by Ahlback et al in 1968. It is described as a disease of subchondral bone that leads to focal ischemia and bone marrow edema, necrosis, and possible subsequent structural collapse. SONK typically presents in the older women with frequent involvement of the medial femoral condyle. Secondary osteonecrosis is typically present in patients below 55 years of age. Unlike SONK, secondary ON presents multiple foci of bone marrow involvement with extension into the metaphysis and diaphysis. Postarthroscopic ON has been described after arthroscopic meniscectomy, shaver-assisted chondroplasty, anterior cruciate ligament reconstruction, and laser or radiofrequency-assisted debridement.

Predictive factors for the progression of spontaneous osteonecrosis of the knee

PURPOSE

To assess potentially predictive factors that were evaluated 1 year after the onset of symptoms in patients with spontaneous osteonecrosis of the knee (SONK) and to determine receiver operating characteristic (ROC) curve cut-off values.

METHODS

Within 1 year of symptom onset, patients with SONK-selected treatment options, mainly based on severity of pain, chose either conservative treatment (n = 27 knees) or operative treatment (n = 27 knees). Knee and whole-leg radiographs, knee MRIs and bone mineral density scans of the lumbar spine, femoral neck and femoral condyles were obtained. The parameters measured were: (1) anatomical angle on whole-leg radiograph and (2) lesion size and medial meniscus extrusion on MRI.

RESULTS

The anatomical angle and lesion size in the sagittal section (depth) on MRI were markedly larger in the operative treatment group than those in the conservative treatment group. The anatomical angle and depth on MRI of SONK at Stages 1-3 were significantly different between groups, with odds ratios (95 % confidence intervals) of 1.16 (1.18-2.34) and 1.11 (1.01-1.23). One year after symptom onset, ROC curve cut-off value for anatomical angle was 180° and depth on MRI was 20 mm.

CONCLUSION

An anatomical angle >180° and depth >20 mm on MRI were predictive factors for a poorer prognosis 1 year after symptom onset in patients with SONK. Our results on radiographs and MRI provided a predictive prognosis for patients with SONK at the initial visit to their orthopaedic surgeons.

LEVEL OF EVIDENCE

III.

MR appearance of the temporal evolution and resolution of spontaneous osteonecrosis of the knee: a case report

Spontaneous osteonecrosis of the knee (SONK) is a feared condition of unknown cause, in its classic form appearing in the medial femoral condyle in middle-aged or elderly subjects. Diagnosis with radiography is notoriously difficult with a long latency before typical changes appear. Magnetic resonance imaging (MRI) is regarded as a diagnostic tool with the possibility to give an earlier diagnosis with improved chances for treatment. However, also with MRI there may be an initial diagnostic blind spot before typical changes appear. Little is known about the temporal evolution of the MRI changes. In the current case report, a case of SONK is reported where serial imaging with MRI was performed, from initial symptoms to eventual resolution after almost three years.

Can a biomimetic osteochondral scaffold be a reliable alternative to prosthetic surgery in treating late-stage SPONK?

BACKGROUND

This study aimed to assess the reliability of the Maioregen® biomimetic osteochondral scaffold (Finceramica Faenza SpA, Faenza, Italy) as a salvage and joint-preserving procedure in the treatment of late-stage osteonecrosis of the knee.

METHODS

Eleven active patients aged under 65years and presenting with clinical and radiological signs of SPONK were treated with Maioregen®. All were clinically evaluated pre-operatively and yearly thereafter for a minimum of two years. Subjective IKDC and Lysholm Knee Scale scores were used to assess clinical outcome. A VAS scale served to quantify pre-operative pain and post-operative pain. Activity levels were evaluated pre-operatively and at follow-up using the Tegner Activity Scale.

RESULTS

Subjective IKDC (40±15.0 to 65.7±14.8 (mean±SD)) and Lysholm Knee Scale (49.7±17.9 to 86.6±12.7 (mean±SD)) scores improved significantly from pre-operative evaluation (p<.01). VAS scores decreased from a pre-operative mean (±SD) of 6.3±2.5 to 1.6±2.7 at two years. The Tegner Activity Scale showed no significant differences between pre-injury and two-year follow-up. Two out of the 11 patients were symptomatic at 18months post implant and progressed to condylar collapse. These patients required total knee arthroplasty.

CONCLUSIONS

Use of a biomimetic scaffold can be a valid option in the surgical treatment of SPONK in relatively young active patients. Indeed, this surgical technique, originally developed for osteochondritis dissecans, has been found to give good clinical results at medium-term follow-up of late-stage osteonecrosis treatment and could postpone or even avoid the need for joint replacement procedures.

A non-invasive, home-based biomechanical therapy for patients with spontaneous osteonecrosis of the knee

BACKGROUND

The purpose of the current study was to examine the effect of a non-invasive, home-based biomechanical treatment program for patients with spontaneous osteonecrosis of the knee (SONK).

METHODS

Seventeen patients with SONK, confirmed by MRI, participated in this retrospective analysis. Patients underwent a spatiotemporal gait analysis and completed the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and the Short-Form-36 (SF-36). Following an initial assessment, patients commenced the biomechanical treatment (AposTherapy). All patients were reassessed after 3 and 6 months of treatment.

RESULTS

A significant reduction in pain and improvement in function was seen after 3 months of therapy with additional improvement after 6 months of therapy. Pain was reduced by 53% and functional limitation reduced by 43%. Furthermore, a significant improvement was also found in the SF-36 subscales, including the summary of physical and mental scores. Significant improvements were found in most of the gait parameters including a 41% increase in gait velocity and a 22% increase in step length. Patients also demonstrated improvement in limb symmetry, especially by increasing the single limb support of the involved limb.

CONCLUSIONS

Applying this therapy allowed patients to be active, while walking more symmetrically and with less pain. With time, the natural course of the disease alongside the activity of the patients with the unique biomechanical device led to a significant reduction in pain and improved gait patterns. Therefore, we believe AposTherapy should be considered as a treatment option for patients with SONK.

TRIAL REGISTRATION

Assaf Harofeh Medical Center Institutional Helsinki Committee Registry, 141/08; ClinicalTrials.gov NCT00767780 .

The importance of early diagnosis in spontaneous osteonecrosis of the knee - A case series with six year follow-up

BACKGROUND

Spontaneous osteonecrosis of the knee has an unknown aetiology. Management options include conservative, surgical and pharmacological interventions. The aim of this study was to report the experience of the authors in conservative management of SONK using non-operative measures by analysing the functional outcome and need for surgical intervention.

MATERIALS AND METHODS

All patients treated for SONK between 1st August 2001 and 1st April 2014 were retrospectively reviewed. Treatment consisted of touch-down weight bearing for around six weeks. MR imaging was evaluated for size of lesion, the condyles involved and the time taken for resolution. Tegner Activity Scale, VAS pain, Lysholm, WOMAC and IKDC scores were recorded at presentation and final follow-up (mean six years, range six months to 13years).

RESULTS

Forty cases were included; the mean age of the group was 55.3years and 67.5% were male. The medial femoral condyle was the most commonly affected (52.5%). A statistically significant improvement was reported in all functional outcome measures (p<0.001). Only one patient required arthroscopic surgical intervention and no patients required arthroplasty during the follow-up period.

CONCLUSION

Early stage spontaneous osteonecrosis of the knee can be managed successfully without surgery if diagnosed early. Thus early investigation of acute knee pain with MRI scanning is recommended.

Aqueous Fraction of Huogu Formula Promotes Osteogenic Differentiation of Bone Marrow Stromal Cells Through the BMP and Wnt Signaling Pathways

Our recent studies have shown that Huogu (HG) formula was effective both in clinic experience and in experimental osteonecrosis of the femoral head (ONFH). Given that defective of bone marrow stromal cells (MSCs) contribute to the development of osteonecrosis and MSCs show enormous potential in the treatment of ONFH, especially to aging people. How HG impacts the differentiation of MSCs and what is the underlying cellular and molecular mechanism remains largely unknown. Here, we found that an aqueous fraction of HG (HGA) significantly increased the alkaline phosphatase (ALP) activity, mineralized nodules, and migration of MSCs in a dose-dependent manner. Meanwhile, HGA could enhance the mRNA and protein expression of Runt-related transcription factor 2 (Runx2), Alp, Bmp2, osteocalcin (Ocn), and Osterix (Osx). Further investigation of the molecular mechanisms revealed that HGA treatment obviously increased expression, secretion, and activation of bone morphogenetic protein (BMP) 2 and β-catenin, two key regulators of the BMP or Wnt signaling pathway. Furthermore, osteogenic differentiation of MSCs could be blocked by using pharmacological inhibitors for these signaling pathways such as Noggin and Dkk-1. Besides, HGA could inhibit adipogenic differentiation of MSCs. Our study reveals that HGA promotes the osteogenesis of MSCs via the BMP and Wnt signaling pathways. Our findings provide mechanistic insights into the role of HG in treating ONFH.

Osteonecrosis of the knee: review

Osteonecrosis is a devastating disease that can lead to end-stage arthritis of various joint including the knee. There are three categories of osteonecrosis that affect the knee: spontaneous osteonecrosis of the knee (SONK), secondary, and post-arthroscopic. Regardless of osteonecrosis categories, the treatment of this disease aims to halt further progression or delay the onset of end-stage arthritis of the knee. However, once substantial joint surface collapse has occurred or there are sign of degenerative arthritis, joint arthroplasty is the most appropriate treatment option. Currently, the non-operative treatment options consist of observation, non-steroidal anti-inflammatory drugs (NSAIDs), protected weight bearing, and analgesia as needed. Operative interventions include joint preserving surgery, unilateral knee arthroplasty (UKA), or total knee arthroplasty (TKA) depending on the extent and type of disease. Joint preserving procedures (i.e., arthroscopy, core decompression, osteochondral autograft, and bone grafting) are usually attempted in pre-collapse and some post-collapse lesions, when the articular cartilage is generally intact with only the underlying subchondral bone being affected. Conversely, after severe subchondral collapse has occurred, procedures that attempt to salvage the joint are rarely successful and joint arthroplasty are necessary to relieve pain. The purpose of this article is to highlight the recent evidence concerning the treatment options across the spectrum of management of osteonecrosis of the knee including lesion observation, medications, joint preserving techniques, and total joint arthroplasties.

Effect of ibandronate on spontaneous osteonecrosis of the knee: a randomized, double-blind, placebo-controlled trial

Based on this double-blind, placebo-controlled study, ibandronate has no beneficial effect on clinical and radiological outcome in patients with spontaneous osteonecrosis of the knee over and above anti-inflammatory medication.

INTRODUCTION

Observational studies suggest beneficial effects of bisphosphonates in spontaneous osteonecrosis (ON) of the knee. We investigated whether ibandronate would improve clinical and radiological outcome in newly diagnosed ON.

METHODS

In this randomized, double-blind, placebo-controlled trial, 30 patients (mean age, 57.3 ± 10.7 years) with ON of the knee were assigned to receive either ibandronate (cumulative dose, 13.5 mg) or placebo intravenously (divided into five doses 12 weeks). All subjects received additional treatment with oral diclofenac (70 mg) and supplementation with calcium carbonate (500 mg) and vitamin D (400 IU) to be taken daily for 12 weeks. Patients were followed for 48 weeks. The primary outcome was the change in pain score after 12 weeks. Secondary endpoints included changes in pain score, mobility, and radiological outcome (MRI) after 48 weeks.

RESULTS

At baseline, both treatment groups (IBN, n = 14; placebo, n = 16) were comparable in relation to pain score and radiological grading (bone marrow edema, ON). After 12 weeks, mean pain score was reduced in both ibandronate- (mean change, -2.98; 95% CI, -4.34 to -1.62) and placebo- (-3.59; 95% CI, -5.07 to -2.12) treated subjects (between-group comparison adjusted for age, sex, and osteonecrosis type, p = ns). Except for significant decrease in bone resorption marker (CTX) in ibandronate-treated subjects (p < 0.01), adjusted mean changes in all functional and radiological outcome measures were comparable between treatment groups after 24 and 48 weeks.

CONCLUSIONS

In patients with spontaneous osteonecrosis of the knee, bisphosphonate treatment (i.e., IV ibandronate) has no beneficial effect over and above anti-inflammatory medication.

The natural course of spontaneous osteonecrosis of the knee (SPONK): a 1- to 27-year follow-up of 40 patients

BACKGROUND AND PURPOSE

Spontaneous osteonecrosis of the knee (SPONK) is a painful lesion in the elderly, frequently leading to osteoarthritis and subsequent knee surgery. We evaluated the natural course and long-term consequences of SPONK in terms of need for major knee surgery.

METHODS

Between 1982 and 1988, 40 consecutive patients were diagnosed with SPONK. The short-term outcome has been reported previously (1991). After 1-7 years, 10 patients had a good radiographic outcome and 30 were considered failures, developing osteoarthritis. In 2012, all 40 of the patients were matched with the Swedish Knee Arthroplasty Register (SKAR) and their medical records were reviewed to evaluate the long-term need for major knee surgery.

RESULTS

At the 2012 review, 33 of the 40 patients had died. The mean follow-up time from diagnosis to surgery, death, or end of study was 9 (1-27) years. 17 of 40 patients had had major knee surgery with either arthroplasty (15) or osteotomy (2). All operated patients but 1 were in the radiographic failure group and had developed osteoarthritis in the study from 1991. 6 of 7 patients with large lesions (> 40% of the AP radiographic view of the condyle) at the time of the diagnosis were operated. None of the 10 patients with a lesion of less than 20% were ever operated.

INTERPRETATION

It appears that the size of the osteonecrotic lesion can be used to predict the outcome. Patients showing early signs of osteoarthritis or with a large osteonecrosis have a high risk of later major knee surgery.

The treatment effect of porous titanium alloy rod on the early stage talar osteonecrosis of sheep

Osteonecrosis of the talus (ONT) may severely affect the function of the ankle joint. Most orthopedists believe that ONT should be treated at an early stage, but a concise and effective surgical treatment is lacking. In this study, porous titanium alloy rods were prepared and implanted into the tali of sheep with early-stage ONT (IM group). The curative effect of the rods was compared to treatment by core decompression (DC group). No significant differences in bone reconstruction were observed between the two groups at 1 month after intervention. After 3 months, the macroscopic view of gross specimens of the IM group showed ordinary contours, but the specimens of the DC group showed obvious partial bone defects and cartilage degeneration. Quantitative analysis of the reconstructed trabeculae by micro-CT and histological study suggested that the curative effect of the IM group was superior to that of the DC group at 3 months after intervention. These favorable short-term results of the implantation of porous titanium alloy rods into the tali of sheep with early-stage ONT may provide insight into an innovative surgical treatment for ONT.