AbstractMeniscal tears are the commonest knee injury and currently are addressed almost exclusively by arthroscopy.
Ian Smillie the late Professor of orthopaedics in Tayside, popularised open total meniscectomy worldwide during the 1950s believing that this was necessary for a functioning fibrocartilage replica to completely occupy the ensuing space.
The cohort in this study underwent open total meniscectomy under his care prior to their 19th birthday. It was documented in their then records that no other knee pathology was observed during the operation and that the same post operative regime was followed by all. This presents a unique opportunity to evaluate the long term outcomes of open total knee meniscectomy during adolescence and to further investigate biological markers of osteoarthritis 40 years down the line.
Fifty-three patients who underwent radiographic evaluation at the 30 year follow-up were further studied at this 40 year review. All surviving and contactable patients were consented prior to assessment and were evaluated clinically; biochemically, radiologically and subjectively once ethical approval and funding were secured.
Standardisation of all methods used for examination, radiographic evaluation, sampling of serum and synovial fluid and patient reported outcome measures (PROMs) was achieved by the use of recognised, validated and credible systems as well as good communication between all involved parties. Such examples include the construction of a wooden apparatus standardising the weight bearing skyline views and the need for a smooth and efficient transition between sampling, preparing, storing and transferring the synovial and serum samples.
Once all the data were collected, the first striking finding was the proportion of total knee arthroplasties (TKAs) observed as a hard endpoint in this cohort, which suggested a 132 fold increase when compared to their age and geographically matched population data, as per Scottish Arthroplasty Project.
It was important to assess if in this cohort the site of meniscectomy demonstrated a significant difference in terms of tibiofemoral joint (TFJ) osteoarthritis, range of motion (ROM) and PROMs as per our chosen scoring systems. As this proved not to be the case, the operated knee was assessed against the non-operated knee where possible and not as per site of meniscectomy.
Also the assessed sagittal laxity between the knees did not demonstrate any significant difference and as such was excluded as a confounding factor in terms of initiators of osteoarthritis.
A linear correlation was observed between the chosen scoring systems of TFJ osteoarthritis. The calculated relative risk (RR) of developing osteoarthritis (OA) in the operated vs. non-operated knee was calculated for both the KL & Ahlback grading systems with presumed osteoarthritis as =2 for KL & =1 for Ahlback. This was found to be 4.5 & 4.25 respectively.
Decreased ROM between the Index and Non-index knees was observed, with the ROM correlating with PROMs and inversely with TFJ OA.
In addition the usually under investigated patellofemoral joint was assessed. Patellofemoral joint osteoarthritis was noted in the index knees as opposed to the non-index knees with an observed RR of 1.8 as per presence of osteophytes. There was no significant difference in the degree of patellofemoral joint (PFJ) osteoarthritis between lateral and medial meniscectomies. There was however significant correlations between the joint space narrowing (JSN) and PROMs, TFJ OA and ROM. Worsening results were observed where the PFJ was <5mm.
Malalignment was greater in those knees that underwent medial meniscectomy as opposed to either lateral or medial & lateral meniscectomies. Malalignment demonstrated correlation with ROM and TFJ OA.
Serum and synovial fluid was processed and analysed with regards to biomarkers of OA in the form of MMP-3 and GAG. Neither serum nor synovial MMP-3 demonstrated any significant correlation with other measured parameters. GAG on the other hand demonstrated a significant difference between the index and non-index knee as well as a positive correlation to IKDC and an inverse correlation with TFJ OA. Although this is suggesting that synovial GAG as a biomarker for OA may indicate progression of disease and symptoms, the wider spread of values questions this.
Two different PROMs were utilised to assess this cohort. Interestingly the KOOS demonstrated that in all its 5 parameters the cohort was symptomatic. Correlations were observed between the KOOS ADL & Sport as well as IKDC with TFJ OA.
This is currently the longest follow-up of open total meniscectomy in adolescence worldwide. A >4 fold increased risk of osteoarthritis in the operated knee as compared to the non-operated knee was demonstrated and possibly a 132 fold increase in TKA as compared to their aged matched geographical peers.
|Date of Award||2012|
|Supervisor||Carlos Wigderowitz (Supervisor)|