S3-Leitline. Teil 1: Diagnostik und Differenzialdiagnostik der atraumatischen Femurkopfnekrose (aFKN) des Erwachsenen

[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.

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

The update of the German S3 guideline on atraumatic femoral head necrosis in adults aims to provide an overview of diagnosis and treatment. All clinical studies, systematic reviews, and meta-analyses published in German or English between 01.05.2013 and 30.04.2017 were included. Of 427 studies, 28 were suitable for analysis. Risk factors are corticosteroids, chemotherapy, kidney transplants, hemoglobinopathies, and alcoholism. Differential diagnoses are for example bone marrow edema, insufficiency fracture, and destructive arthropathy. Radiography should be performed upon clinical suspicion. In patients with normal radiography findings but persistent complaints, magnetic resonance imaging (ARCO classification) is the method of choice. Computed tomography (CT) can be used to confirm/exclude articular surface collapse. A subchondral sclerosis zone >30% in CT indicates a better prognosis. Left untreated, a subchondral fracture will develop within 2 years. The risk of disease development in the opposite side is high during the first 2 years, but unlikely thereafter. In conservative therapy, iloprost and alendronate can be used in a curative approach, the latter for small, primarily medial necrosis. Conservative therapy alone as well as other drug-based and physical approaches are not suitable for treatment. No particular joint-preserving surgery can currently be recommended. Core decompression should be performed in early stages with <30% necrosis. From ARCO stage IIIc or in stage IV, the indication for total hip arthroplasty should be checked. Results after total hip arthroplasty are comparable with those after coxarthrosis, although the revision rate is higher due to the relatively young age of patients. Statements on the effectiveness of cell-based therapies such as expanded stem cells or bone marrow aspirates cannot currently be made.

[Imaging and classification of avascular femoral head necrosis]

Avascular femoral head necrosis (AVNFH) is difficult to diagnose on plain radiographs in early stages of the disease. Since early stages are often clinically occult, early use of MRI is required to rule out or verify a clinical suspicion. MRI and, in some cases, additional CT are the cornerstones of AVNFH diagnosis and classification. Anteroposterior radiography of the pelvis and a second plane of the involved hip remains the primary basic imaging examination for follow-up and to rule out other pathologies. Correct staging of adult disease has been shown to be the key factor in therapeutic decision-making. According to the German S3 guideline on diagnosis and treatment of AVNFH, use of the ARCO classification is recommended for staging. This paper presents the current status of diagnosis and classification of adult AVNFH. The criteria for ascribing disease to a particular ARCO stage are defined and critically discussed.

[Joint-preserving operative treatment of avascular necrosis of the femoral head]

The cause of avascular necrosis of the femoral head is multifactorial. Conservative treatment is only an option in the early stages. It is only symptomatic and not causative treatment. The implantation of an artificial hip joint should be postponed as the typically affected middle-aged males are right in the middle of their working life. Therefore, some joint-preserving operative therapies might be considered in stages ARCO I-III. Those range from core decompression to osteotomies and grafts, the advantages and disadvantages of which have to be weighted in each case. More recent therapies such as additive stem cells or platelet rich plasma (PRP) combined with core decompression have yet to prove their efficacy.

S3-Guideline non-traumatic adult femoral head necrosis

INTRODUCTION

The treatment of adult non-traumatic avascular necrosis of the femoral head (AVN; N-ANFH) within an estimated incidence of 5000-7000 cases per annum in Germany remains a challenge. Risk factors include steroids, alcohol abuse, chemotherapy and immunosuppressive medication, but a genetic predisposition has been suggested. Early diagnosis of this often bilateral disease process is essential for successful conservative or joint preserving surgical management. In this review, we present the update German consensus S3 guideline "diagnosis and management for N-ANFH" as a concise summary.

MATERIALS AND METHODS

This systematic review is based on the published literature from January 1, 1970 to April 31, 2013 (German and English language). Inclusion criteria were systematic reviews, meta-analyses and relevant peer review publications. We identified a total of 3715 related publications, of which 422 were suitable according to the SIGN criteria, but only 159 fulfilled our inclusion criteria.

RESULTS AND CONCLUSIONS

Clinical suspicion of N-ANFH mandates radiographic evaluation. If radiographs are normal MRI scans are recommended, which should be evaluated according to the ARCO-classification. Differential diagnoses include transient osteoporosis, bone bruise, insufficiency fracture and destructive arthropathy. Untreated, subchondral fractures commonly occur within 2 years, during which the risk for contralateral involvement is high-thereafter unlikely. Conservative management with Ilomedin and Alendronat can be tried, but other pharmacological or physical treatments are inappropriate. No specific joint preserving procedure can be recommended, but core decompression should be considered in early stages if necrosis is <30 %. In ARCO stages IIIc or IV total hip arthroplasty (THA) should be contemplated, which offers similar outcome compared to osteoarthritis. Young age is the main risk factor for higher revision rates after THA for N-ANFH.