Knee Osteoarthritis (KOA) is a common chronic disease, which often leads to joint pain and
limited function in the elderly, and thus affects participants' quality of life. Total knee
arthroplasty (TKA) has been developed as a mature surgical procedure to relieve end-stage
osteoarthritic joint pain and improve limb function. Although more than 80% of the patients
reported in the literature are satisfied with the postoperative efficacy of TKA, there are
still a large number of patients whose daily life is affected by persistent knee pain and
limited function after the operation of the affected limb.
The IPFP is a fat mass located behind the patellar ligament, between the lower part of the
patella and the tibial tubercle. The function of IPFP is controversial at present. It is
reported that IPFP can provide blood supply for anterior cruciate ligament, patella and
patellar ligament through the arterial network of the knee joint. In addition, it can fill
the joint gap to lubricate the surface of the joint, reduce friction and absorb impulse so as
to play a physiological protective role. On the contrary, studies have pointed out that
abnormal IPFP could produce various pro-inflammatory cytokines such as interleukin (IL)-1β,
tumour necrosis factor (TNF)-α, IL-6 and IL-8, as well as adipokines such as leptin and
resistin, and thus might play a detrimental role in knee OA. Traditionally, the IPFP has been
removed in order to improve surgical exposure and to prevent interposition during baseplate
implantation. Despite the significant evolution of TKA technology which no longer requires
the resection of IPFP for better surgical access, IPFP is still partially or totally resected
in around 88% of TKAs.
The investigators' previous population-based cohort study revealed that IPFP maximal area and
volume were associated with reduced knee pain, decreased loss of cartilage volume and reduced
risks of cartilage defect progression, indicating a beneficial effect of IPFP size. On the
other hand, the investigators' further investigation demonstrated that IPFP signal intensity
alteration was negatively associated with maximum area of IPFP, and moreover, associated with
increased knee cartilage defects, subchondral bone marrow lesion (BML) and knee pain,
suggesting IPFP with abnormal quality may play a detrimental role in knee OA. Based on these
findings, the investigators proposed that IPFP with normal quality should be preserved or not
damaged during TKA, while IPFP with abnormal quality should be resected. This multicentre
randomised controlled trial is designed to test the investigators' hypotheses: in patients
with normal IPFP quality, preservation of IPFP during TKA procedure will reduce postoperative
knee symptoms and improve joint function, comparing with IPFP resection during TKA
procedures; in patients with abnormal IPFP quality, resection of IPFP during TKA procedure
will reduce postoperative knee symptoms and improve joint function, comparing with IPFP
preservation during TKA procedures. The results would provide evidence-based recommendations
on clinical practice to improve OA patients' postoperative outcomes.
Three hundred and sixty eligible participants will be recruited and identified as having
normal IPFP quality (signal intensity alteration score ≤ 1) or abnormal IPFP quality (signal
intensity alteration score ≥ 2). Participants in each site will be randomly allocated to IPFP
resection group or preservation group using computer-generated block randomisation.