Though knee osteoarthritis (OA) is diagnosed and monitored radiographically, full thickness cartilage loss (FTCL) has rarely been correlated with radiographic classification. This study aims to analyse which classification system correlates best with FTCL and assessing their reliability. Prospective study of 300 consecutive patients undergoing total knee arthroplasty (TKA) for OA. Two blinded examiners independently graded preoperative radiographs using 5 systems: Kellgren-Lawrence (KL); International Knee Documentation Committee (IKDC); Fairbank; Brandt; and Ahlback. Interobserver agreement was assessed using the intraclass correlation coefficient. Intraoperatively, anterior cruciate ligament (ACL) status and FTCL in 16 regions of interest were recorded. Radiographic classification and FTCL were correlated using the Spearman correlation coefficient. On average, each knee had 6.8±3.1 regions of FTCL, most common medially. The commonest patterns of FTCL were medial with patellofemoral (48%) and tricompartmental (30%). ACL status was associated with pattern of FTCL (p=0.02). All classification systems demonstrated moderate ICC, but this was highest for IKDC: whole knee 0.68 (95%CI 0.60–0.74); medial compartment 0.84 (0.80–0.87); and lateral compartment 0.79 (0.73–0.83). Correlation with FTCL was strongest for Ahlback (Spearman rho 0.27–0.39) and KL (0.30–0.33), though all systems demonstrated medium correlation. The Ahlback was the most discriminating in severe OA. Osteophyte presence in the medial compartment had high positive predictive value for FTCL, but not in the lateral compartment. The Ahlback and KL systems had the highest correlation with confirmed cartilage loss. However, the IKDC system displayed best interobserver reliability, with favourable correlation with FTCL in medial and lateral compartments, though less discriminating in severe disease

INTRODUCTION. Autologous bone grafts are considered gold standard in the repair of bone defects. However they are limited in supply and are associated with donor site morbidity. This has led to the development of synthetic bone graft substitute (BGS) materials, many of which have been reported as being osteoinductive. The structure of the BGS is important and bone formation has been observed in scaffolds with a macroporous morphology. Smaller pores termed ‘strut porosity’ may also be important for osteoinduction. The aim of this study was to compare the osteoinductive ability of one silicate-substituted calcium phosphate (SiCaP) with differing strut porosities in an ectopic ovine model. Our hypothesis was that SiCaP with greater strut porosity would be more osteoinductive. METHODS. The osteoinduction of SiCaP BGS with two different strut porosities (AF and AF++) was investigated. The materials had an identical chemical composition and morphological structure but differing strut porosity (AF=22.5%, AF++=47%). Implants were inserted into the paraspinal muscles in skeletally mature sheep. Procedures were carried out in compliance with UK Home Office regulations. There were 12 implants in each group. Implants remained in vivo for 8 and 12 weeks and on retrieval were prepared for undecalcified histology. Sections were stained and examined using light microscopy. A line intersection method was used to quantify bone, implant and implant surface/bone contact within seven random regions of interest along each implant. A Mann-Whitney U test was used for statistical analysis where p values < 0.05 were considered significant. RESULTS. Bone formation was observed to be greater in the AF++ group at 8 (AF=0.2%+/−0.15; AF++=0.44%+/−0.12) and significantly higher at 12 weeks (AF=1.33% +/−0.84; AF++=6.17%+/−1.51) (p=0.04). Significantly higher implant surface/bone contact was observed in the AF++ group at 8 (AF=0.67%+/−0.52; AF++=3.30%+/−1.17) (p=0.04) and 12 weeks (AF=3.06%+/−1.89; AF++=21.82%+/−5.59) (p=0.01). The % implant measured was less in the AF++ group at 8 (AF=39.06%+/−1.26; AF++=33.09%+/−2.14) and 12 weeks (AF=36.05% +/−3.55; AF++=30.60%+/−2.29) but this was not significant. Histology revealed bone formation within BGS strut pores measuring < 50um. Endochondral and intramembranous ossification were also observed in both groups. DISCUSSION. The results indicate that higher strut porosity promotes greater osteoinduction in SiCaP materials. This could be attributed to the micropores providing a greater surface area for the action of growth factors and osteoblasts leading to the formation of bone at an earlier time point. Endochondral ossification was an unusual finding as this is usually associated with bone formation secondary to Bone Morphogenetic proteins (BMPs). This suggests that the osteoinductive mechanisms by SiCaP may involve cytokines such as BMPs

Aims

Dual plating of distal femoral fractures with medial and lateral implants has been performed to improve construct mechanics and alignment, in cases where isolated lateral plating would be insufficient. This may potentially compromise vascularity, paradoxically impairing healing. This study investigates effects of single versus dual plating on distal femoral vascularity.