What are the outcomes of core decompression in patients with avascular necrosis? Protocol for a systematic review

Introduction

Osteonecrosis or avascular necrosis (AVN) of the femoral head is a challenging condition that eventually leads, in the majority of cases, to a total hip replacement (THR)^1–3. The patients affected by the condition are usually young and therefore may require revision surgery and multiple further procedures⁴. The aetiology is varied and includes multiple conditions that can lead to a reduced blood supply in the femoral head: oral corticosteroids, systemic lupus erythematosus, binge consumption of alcohol, Gaucher disease, sickle cell anaemia, trauma, thrombosis amongst others⁵. Furthermore, staging systems for AVN are different across the literature and pose a significant problem in assessing surgical indications and stratifying outcome⁶. The most common classification systems used are: Ficat⁷/ Modified Ficat⁸; “University of Pennsylvania”/Steinberg⁶; and ARCO (Association Research Circulation Osseous)⁹.

Core decompression is a common surgical procedure that has been used earlier on in the disease process to decrease the intraosseous pressure in the femoral head, relieve pain and potentially re-establish blood flow. Furthermore, multiple augmentation techniques have recently been described that seem to significantly improve the outcome following this procedure^10,11.

However, the eventual outcome and time to THR following this procedure remains controversial^12–16. It is also not clear whether a mechanical decompression alone is sufficient and efficient in all stages of AVN in order to prevent progression and delay the need of a THR. To the best of our knowledge, the largest published systematic review on this subject included only four studies for analysis¹⁷.

The purpose of this study, therefore, was to assess the outcomes of core decompression without any augmentation for nontraumatic AVN of the femoral head.

Methods/design

Study status

Ongoing.

Discussion

Classification systems, outcome measures and reporting systems are highly variable amongst studies assessing and reporting the outcome of core decompression for AVN of the femoral head. From distinct classifications (Ficat or its modification, Steinberg, ARCO) to varied clinical scores (Harris Hip Score/D’Aubigne/Visual Analogue Scale), all have been described and used in the literature.

Furthermore, the concept of “procedural success” is not absolute. Whilst most studies consider the absence of radiological progression of disease to be the main finding that suggests success, other authors interpret clinical improvement as success, even in the presence of radiological deterioration. Therefore, the heterogeneity of interpretation of success in the studies extracted may not allow for a uniform representation. As such, the results will be represented in separate categories, based on the classification system that was used and divided into radiological progression and another category of clinical improvement.

The strengths of our study will be represented by the largest patient pool and rigorous exclusion criteria that will be used. Any collateral influence of aetiology (traumatic), systemic disease (sickle cell crisis) or technique heterogeneity (presence of augmentation or bone grafts) will be excluded. Also, there will be a tenacious stratification based on stage of the disease even in the presence of a variety of classification systems. Ultimately, the following questions will be evaluated and answered:

1) Does core decompression accomplish postoperative pain relief/clinical or functional improvement?

2) In what percentage of the patients does core decompression achieve a cessation of radiological progression?

3) What percentage of patients undergoing core decompression without augmentation, ultimately require a THR?

4) What is the average time to requiring a THR following core decompression?

Data availability

Author information

VK (MD, MA, MSc, FRCS(Orth)) is a Consultant Orthopaedic Surgeon at Addenbrooke’s - Cambridge University Hospital, England, UK. VK is also an Associate Lecturer at the University of Cambridge and the Associate Editor at the Bone and Joint Journal. He is also the Chair of SICOT Education Academy and Chair of the UK’s non-arthroplasty hip registry. OA (MD) is VK’s research fellow and orthopaedic surgery resident at the Balgrist University Hospital in Zurich, Switzerland. OW (MD) is VK’s research fellow and orthopaedic surgery resident at the Meir Medical Center, Kfar-Saba, Israel. HS (MD, DIC, MPH) is also VK’s research fellow and a Global Surgery Research Fellow at Harvard Medical School, Boston, MA, USA.