[Update of the German S3 guideline on atraumatic femoral head necrosis in adults]

[Pharmacological therapy for subchondral pathologies of the knee joint]

BACKGROUND

Pathologies of the subchondral bone include both structural alterations such as osteonecrosis and bone marrow edema. Both entities are amenable to pharmacological therapy.

OBJECTIVE

Presentation of current recommendations for drug therapy of osteonecrosis and bone marrow edema of the knee joint based on the clinical data.

METHODS

The currently available literature is evaluated and discussed.

RESULTS

Antiresorptives such as bisphosphonates and denosumab and the osteoanabolic agent teriparatide therapeutically address the locally diminished bone density potentially resulting in insufficiency fractures. In contrast, vitamin K antagonists, heparin and new/direct oral anticoagulants, as well as iloprost exert their effects at the vascular and hemostatic level. All drug treatment concepts are "off-label" use. They are particularly promising in the early stages of primary, idiopathic osteonecrosis and bone marrow edema.

CONCLUSION

In osteonecrosis and bone marrow edema of the knee joint, complementary drug therapy may be beneficial. However, the available data is not yet sufficiently robust for general treatment recommendations.

Knowledge mapping of core decompression in osteonecrosis of the femoral head: a bibliometric analysis

Background

Osteonecrosis of the femoral head (ONFH), caused by disrupted blood supply leading to bone cell death and joint collapse, remains a critical orthopedic challenge. While core decompression has advanced significantly in ONFH treatment, no bibliometric analysis has mapped its research landscape.

Method

We analyzed 854 articles from the Web of Science Core Collection (1986-2023) using VOSviewer, CiteSpace, and bibliometrix.

Results

Publications surged from 5.4/year (1986-2001) to 52.3/year (2015-2023), reflecting intensified interest. China (253 articles, 29.6%) and the United States (232, 27.2%) dominated contributions, with Stanford University and Johns Hopkins University as top institutions. International collaborations linked China to the United States, Germany, and England. Clinical Orthopaedics and Related Research was the most cited journal (4708 citations). Keyword analysis revealed emerging hotspots: mesenchymal stem cells (19 occurrences), cell therapy, and angiogenesis. Citation bursts highlighted Mont MA's seminal work (burst strength: 19.67) on joint-preserving strategies and stem cell-enhanced core decompression.

Conclusion

This first bibliometric study delineates trends, collaborations, and frontiers in core decompression for ONFH, emphasizing the translational potential of stem cell therapies.

Comparison of current treatment strategy for osteonecrosis of the femoral head from the perspective of cell therapy

Aims: The purpose of our study is to compare the effects of core decompression (CD) and bone grafting (BG) on osteonecrosis of the femoral head (ONFH). And evaluate the efficacy of CD based on cell therapy to provide guidance for the dose and number of cells. Methods: We searched PubMed, Embase, and the Cochrane Library between 2012 and 2022, with keywords including "osteonecrosis of the femoral head", "core decompression" and "bone grafting". We selected comparative studies of CD and BG, and the comparison of CD combined with bone marrow (BM) transplantation and CD alone. Changes in hip pain were assessed by VAS, hip function were assessed by HHS and WOMAC, and THA conversion rate was used as an evaluation tool for femoral head collapse. From these three aspects, the dose of bone marrow and the number of cells transplantation were subgroup analyzed. Results: Eleven studies were used to compare the efficacy of CD and BG. There was no significant difference in HHS, and the THA conversion rate of BG was significantly lower than that of CD. Thirteen CD studies based on cell therapy were included in the meta-analysis. Bone marrow aspiration concentrate (BMAC) can significantly improve VAS (mean difference (MD), 10.15; 95% confidence intervals (CI) 7.35 to 12.96, p < 0.00001) and reduce THA conversion rate (odds ratio (OR), 2.38; 95% CI 1.26 to 4.47, p = 0.007). Medium dose bone marrow fluid has a lower p-value in THA conversion rate. The p values of bone marrow mononuclear cells (BMMC) of 10⁹ magnitude in VAS score were lower. Conclusion: In general, there is no consensus on the use of BG in the treatment of ONFH. The enhancement of cell-based CD procedure shows promising results. Using 20 mL BMAC and 10⁹ magnitude BMMC is likely to achieve better results.

Bioactivation of scaffolds in osteonecrosis

Avascular osteonecrosis (AVN) due to local ischemia leads to an inhomogeneous osseous defect, which can be treated by resection and with bone substitute materials in a joint-preserving treatment. Due to the underlying risk profile of AVN, the mostly subchondral localization and the size of the local bone defect, bone regeneration is impaired. Therefore, bioactivation of the applied bone substitute materials prior to application is highly desirable. Apart from the use of growth factors and other soluble substances, the autologous application of location-typical cells and tissue is a useful alternative to support the bone healing properties of scaffolds. This article presents various methods to activate scaffolds for bone stimulation and discusses these techniques with respect to recent data from the literature.

[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.

[The importance of removing osteonecrosis during treatment of femoral head osteonecrosis]

Atraumatic femoral head necrosis (aFHN) in adults is estimated to be the leading cause of approximately 10% of all hip prosthesis implantations. Due to the relatively frequent occurrence of aFHN at a young age, the possibility of a joint-preserving intervention should be examined. This includes the classic "core decompression" and modifications based on it. There are different data on the success rates of this method. Reasons for treatment failure could include a lack of clearance of the necrosis zone. The clearance of the necrosis zone is taken into account by alternative surgical procedures for the treatment of aFHN. These are the "trap-door procedure", the "light-bulb procedure" and "advanced core decompression". The current state of knowledge on these procedures is reviewed in this keynote article. It is shown that the extensive excision of femoral head necrosis is of particular importance. None of the procedures mentioned can currently be recommended in preference over the others.

Treatment of non-traumatic avascular necrosis of the femoral head (Review)

Non-traumatic osteonecrosis of the femoral head is the main cause of disability in young individuals and incurs major health care expenditure. The lifestyle changes in recent years, especially increased use of hormones and alcohol consumption, has greatly increased the incidence of femoral head necrosis. The underlying causes and risk factors of osteonecrosis of the femoral head are increasingly being elucidated, which has led to the development of novel surgical and non-surgical treatment options. Although the main goal of any treatment method is prevention and delaying the progression of disease, there is no common consensus on the most suitable method of treatment. The present review discussed the latest developments in the etiology and treatment methods for femoral head necrosis.

Cone beam-navigated core decompression of bone marrow edema syndrome

INTRODUCTION

The aim of the study was to compare decompression of bone-marrow edema or osteonecrosis of the proximal femur by means of a cone beam-based imaging and navigation system (cone beam-navigated decompression, CBND) with decompression by the conventional technique of drilling using fluoroscopy (FD).

MATERIALS AND METHODS

The data of patients with bone-marrow edema syndrome treated between 2016 and 2018 by drilling of the proximal femur in CBND or FD technique were compared retrospectively.

RESULTS

Each treatment group included 20 patients. The mean operating time for CBND was 16.4 ± 5.8 min, compared with 29.1 ± 20.8 min for FD (p = 0.018). The lesion was definitely reached by CBND in 19/20 patients. Eighteen of the 20 patients in the CBND group reported that their pain decreased after the treatment, compared with 12/20 patients in the FD group (p = 0.065). The radiation dosage was significantly higher (p < 0.001) for CBND than for FD.

CONCLUSION

Decompression by CBND can be carried out safely and without complications. The advantages of CBND over FD are the minimally invasive access and the ability to address the affected area precisely with only one drilling maneuver. The high radiation dose of CBND can be reduced using low-dose protocols.

Efficacy and safety of stem cell therapy for the early-stage osteonecrosis of femoral head: a systematic review and meta-analysis of randomized controlled trials

Background

Osteonecrosis of femoral head (ONFH) is a seriously degenerative disease with no effective therapies to slow its progression. Several studies have reported short-term efficacy of stem cells on early-stage ONFH. However, its long-term effect was still unclear especially on progression events. This study was performed to evaluate the long-term efficacy and safety of stem cells and analyze its optimal age group and cell number.

Methods

Our review was registered on PROSPERO (http://www.crd.york.ac.uk/PROSPERO), registration number CRD42020136094. Following PRISMA guideline, we searched 8 electronic databases on January 5, 2020, and rigorous random controlled trials (RCTs) utilizing stem cell therapy on early-stage ONFH were included. Quality and bias were analyzed. Pooled analysis was performed to assess difference between various outcomes.

Results

A total of 13 RCTs (619 patients with 855 hips) were included. The application of stem cells significantly delayed collapse of femoral head(I², 70%; RR, 0.54; 95% CI, 0.33 to 0.89; P < .00001) and total hip replacement (THR) (I², 68%; RR, 0.55; 95% CI, 0.34 to 0.90; P = .02) in the long term. It effectively decreased the events of collapse of femoral head (≥ 60 months) (I², 0%; RR, 0.37; 95% CI, 0.28 to 0.49; P < .00001) and THR (> 36 months) (I², 0%; RR, 0.32; 95% CI, 0.23 to 0.44; P < .00001). There existed a beneficial effect for patients under 40 (Collapse of femoral head: I², 56%; RR, 0.41; 95% CI, 0.23 to 0.76; P = .004) (THR: I², 0%; RR, 0.31; 95% CI, 0.23 to 0.42; P < .00001). In addition, quantity of stem cells at 10⁸ magnitude had better effects on disease progression events (I², 0%; RR, 0.34; 95%CI, 0.16 to 0.74; P = .007). Besides, there were no significant differences on adverse events between the stem cell group and control group (I², 0%; RR, 0.82; 95% CI, 0.39 to 1.73; P = .60).

Conclusion

Our findings build solid evidence that stem cell therapy could be expected to have a long-term effect on preventing early-stage ONFH patients from progression events, such as collapse of femoral head and total hip replacement. Furthermore, patients under 40 may be an ideal age group and the optimal cell number could be at 10⁸ magnitude for this therapy. Further studies including strict RCTs are required to evaluate a clear effect of stem cells on ideal patient profile and the procedures of implantation.

Computer assistance in hip preservation surgery-current status and introduction of our system

INTRODUCTION

Preservation surgery of the hip with open or arthroscopic approach has always been challenging as complex 3-D anatomy and limited surgical access make intraoperative evaluation difficult. Recent advances in computer technology offer a wide range of innovative solutions with a goal to improve accuracy and safety of corrective procedures on human joints.

METHOD

The author critically reviews currently available literature in the field of computer assistance in hip preservation surgery. Basic features of unique planning software and navigation surgical system used in treatment of femoroacetabular impingement and hip dysplasia are introduced.

RESULTS

Currently available software provides preoperative identification of hip deformity on CT-based 3-D model and planning of the surgical correction using kinematic protocols. Real-time intraoperative 3-D orientation is possible, and execution of surgical correction can be performed either with navigation of surgical tools or with printed templates. Computer assistance in hip preservation surgery is in the developing phase. First clinical experiences of its use in treatment of femoroacetabular impingement, hip dysplasia, hip tumors, and avascular necrosis of the femoral head are promising.

CONCLUSION

Computer assistance has been applied for treatment of several hip disorders. Technical advances are suggested and quality basic studies and clinical trials are encouraged for the novel technology to become more user friendly and widely accepted.

[Modified advanced core decompression (mACD)]

OBJECTIVE

The modified advanced core decompression (mACD) combines the advantages of a low invasive core decompression with maximal removal of osteonecrotic bone and a biologic reconstruction of the resulting bone defect.

INDICATIONS

Avascular (atraumatic) osteonecrosis of the femoral head (ARCO stage II).

CONTRAINDICATIONS

Subchondral fractures (ARCO stage III); advanced osteoarthritis (e.g., ACRO stage IV); persisting risk factors such as high-dose corticoid therapy, chemotherapy, alcohol abuse; open growth plates; history of side effects or intolerance to components of the applied bone substitute; lack of patient compliance; osteomyelitis or other septic conditions.

SURGICAL TECHNIQUE

Supine positioning on the operation table, skin disinfection, and sterile draping. Skin incision and core decompression using a 3.2 mm guide wire. Removal of a bone cylinder from a nonaffected area of the femoral neck using a hollow trephine. Drilling of the osteonecrotic area over the applied wire up to 5 mm to the subchondral bone under fluoroscopy, insertion of an expandable bone knife and removal of the osteonecrotic bone supported by a curette. Bone grafting of the autologous bone into the subchondral defect zone and filling of the drill canal by resorbable bone substitute.

POSTOPERATIVE MANAGEMENT

Bed rest for 24 h, then partial weight bearing (20 kg) on crutches for 2-6 weeks depending on the bone quality in the defect zone and the applied bone substitute.

RESULTS

Midterm superiority (2 years) in hip survival of the mACD over advanced core depression and core depression, especially in ARCO stage II.

[Pedicled vascularized iliac bone graft for treatment of osteonecrosis of the femoral head]

OBJECTIVE

Illustration of a nowadays only rarely performed operative procedure for the treatment of osteonecrosis of the femoral head to prevent or at least delay advanced arthrosis and the need for a total hip replacement. The pedicled vascularized iliac bone graft is raised without the need for special microsurgical techniques and has less vascular complications often seen in free vascularized grafts.

INDICATIONS

Early stages of osteonecrosis of the femoral head stages II and III according to the Association Research Circulation Osseous (ARCO) up to the detection of fracture lines (crescent sign) but without mechanical insufficiency.

CONTRAINDICATIONS

Osteonecrosis of the femoral head with collapse of the femoral head (ARCO stage ≥IIIB) and mechanical insufficiency. Patients who are noncompliant or a not able to take the weight off the operated leg. Patients who had radiotherapy or an operation on ipsilateral inguinal lymph nodes and patients who have vascular anomalies or severe arteriosclerosis.

SURGICAL TECHNIQUE

Debridement of the femoral head osteonecrosis and implantation of a pedicled vascularized iliac bone graft.

POSTOPERATIVE MANAGEMENT

Free movement of the hip joint 4 weeks after surgery. Outward rotation of the hip joint allowed after 3 months and restriction of weight load on the operated leg for at least 3-6 months postoperatively depending on the bony consolidation.

RESULTS

Vascularized bone grafts for the treatment of femoral head necrosis show better clinical and radiological results than avascular bone grafts. Nevertheless, after 5 years follow-up approximately 25% of the operated hips formerly in stage II show further progression of radiological necrosis. In stage III all hips eventually show progress of femoral head collapse and the need of a total hip replacement. Concerning the outcome of a free vascularized bone graft (fibula flap) compared to the pedicled vascularized graft from the iliac crest for treatment, the anatomically demanding area and a higher complication rate should be considered even though the cancellous bone of the iliac crest is biologically ideal. Nowadays a free vascularized fibular graft is the most frequently used bone graft for treatment of femoral head necrosis.

[Core decompression ("conventional method") in atraumatic osteonecrosis of the hip]

OBJECTIVE

Retrograde drilling of a necrotic zone within the femoral head to reduce intraosseous pressure and stimulate revascularization.

INDICATIONS

Atraumatic osteonecrosis of the hip ARCO stage I (reversible) and ARCO stage II (potentially reversible) with a medial or central necrotic zone <30% or ARCO stage III with a subchondral fracture for reduction of pain.

CONTRAINDICATIONS

ARCO stage III C, ARCO stage IV (secondary osteoarthritis), stage-independent necrotic zone > 30%, infections.

SURGICAL TECHNIQUE

Supine position. Visualization of the necrotic zone via an image intensifier, approach is determined by using a Kirschner wire, laterodorsal skin incision on a level with the wire, longitudinal incision of iliotibial band and vastus lateralis muscle, drilling the necrotic zone with a 2-3 mm Kirschner wire, optionally placing more wires or a hollow drill, wound closure.

POSTOPERATIVE MANAGEMENT

Partial weightbearing with 20 kg for 6 weeks due to risk of fracture, followed by avoidance of jumping or sprinting for another 6 weeks; physiotherapy from day 1 after surgery, thromboembolic prophylaxis until full weightbearing is possible.

RESULTS

Results are dependent on ARCO stages and are promising in early stages.