Management of the bone loss by metaphyseal sleeves in primary and revision knee arthroplasty: clinical experience and outcome after forty three cases

Management of metaphyseal bone loss in complex primary and revision TKA is a challenge for surgeons. Out of various types of bony defects, large metaphyseal bone loss (AORI types IIB and III) requires special augments in the form of cones or sleeves. The aim of this study is to assess the reliability of metaphyseal sleeves, in dealing with massive bone defects to provide stability for immediate weight bearing and also to check short to mid-term survivorship of metaphyseal sleeves in Asian population by assessing various parameters and complications.

This is a retrospective study that includes 36 patients (43 knees), operated from 2011 to 2019. Patients with AORI type IIB (large metaphyseal bone defect) and AORI type III (metaphyseal defect with compromised collateral ligaments) were included. We included both the primary and revision knee arthroplasties in our study. Our interest in this study was to look for incidence of intra-operative iatrogenic fracture on the one hand, and post-operative complications in the form of peri-prosthetic joint infection and aseptic loosening on the other hand. Knee Society Score (KSS) was used to assess improvement in patient’s clinical outcome. SPSS version 23 was used to process data.

The average age of patients in our study was 59.4 (SD 9.78) years. Male to female ratio was 21:15. The average follow-up was 5.42 (SD 2.24) years with the longest follow up of nine years. Metaphyseal sleeves were used in 12 primary TKA and 31 revision TKA. During surgery, iatrogenic fracture of tibial condyle was encountered in three patients (6.9%), all were managed without any intervention and union was achieved in all cases. There was not a single case with aseptic loosening as per radiological criteria in our study. Peri-prosthetic joint infection (PJI) was encountered in a single case (2.3%). Pre-op Knee Society Score (KSS) was 36.21 (SD 7.43) where as it improved to 92.00 (SD 5.66), six months after surgery. Also the range of flexion was increased from 76.83^o (SD 14.07^o) to 122.91^o (SD 4.84^o).

In our study, metaphyseal sleeves showed excellent short to mid-term survivorship in AORI types IIB and III boneloss in Asian population. These results are comparable to various studies conducted on North American and European population. Metaphyseal sleeve is a reliable tool in the armamentarium of the arthroplasty surgeon. It is user friendly implant and provides immediate stability to allow full weight-bearing mobilization.