9/ Full Paper: “Combining four patient-reported outcome measurement instruments to develop a common metric computerized adaptive test to measure outcome after total knee arthroplasty” 📄

8/ Take-home: * OKS, OKS-APQ, FJS, & HAAS can be linked to a common “knee health” metric. * CAT cuts item burden while preserving precision. * Opens the door for harmonised PROM reporting in TKA trials & registries.

7/ Why it matters: * Avoids ceiling/floor effects of single PROMs * Reduces patient burden (fewer Qs, higher completion rates) * Enables standardisation across RCTs, registries, & meta-analyses * First CAT spanning multiple orthopaedic PROMs

6/ The CAT uses questions from every PROM, with the starting question coming from the OKS relating to pain related to work.

5/ Results: ✅ All four PROMs measured the same latent construct = “knee health” ✅ Combined scale gave higher information (precision) than any PROM alone (orange line) ✅ CAT reduced 36 items → *median 8 items* (range 3–36) with high reliability (SEM 0.29 ≈ rel. 0.9)

4/ Methods: * 6,301 paired responses (preop, 6m, 12m) across PROMs * OKS used as anchor instrument * Item response theory model fitted after confirming assumptions: ✅unidimensionality ✅monotonicity ✅ local independence ✅ measurement invariance

3/ Why a CAT? Combining 4 instruments = 36 Qs, with patients asked the same thing repeatedly (e.g. “can you walk?”). CAT skips redundancy—if you can’t walk 15 mins, it won’t ask about running, but about mobility in the house.

2/ Why? TKA outcomes use multiple PROMs, making studies hard to compare + each has floor/ceiling effects. A common metric would improve precision & allow cross-study comparison—modern test theory lets us calibrate instruments to the same scale.

🧵1/ New @BoneJointJ: Combining four PROM instruments into a common metric CAT. In this paper, we combined 4 common PROMs: * Oxford Knee Score (OKS) * OKS Activity & Participation Questionnaire (OKS-APQ) * Forgotten Joint Score (FJS) * High Activity Arthroplasty Score (HAAS)

Grateful for my supervisors for supporting me through this! @AndyMetOrtho, @mrjnrodrigues, @conrad_harrison, @EdinburghKnee, @dmacdonhbt & Nick Clement

❓What’s exciting here OKS and OKS-APQ measure one latent trait, coined as ‘knee health’ Therefore, scores can be combined, potentially overcoming floor and ceiling effects. To find out how to do – watch this space!

❓Why is IRT ‘better’ Produces truly continuous scores Accounts for missing data, no need to impute missing data or discard responses Easy to use: free web-app can convert scores and do the hard work for you! https://t.co/zqQm581aJT

❓Do you use Oxford Knee Score to evaluate TKR? In clinical practice or research: this is for you! 📰 New article in J Clinic Epidemiology, part of my PhD, looks at modern test theory adaption of the OKS 🧵.. https://t.co/LwxDMKd5CL

Glad to see still going strong!

**Our Expert Report for the UK Covid-19 Public Inquiry** Unveiling the hidden impact: Colorectal cancer It was a humbling privilege to present evidence to the UK COVID Public Inquiry yesterday. @dnepo and I wrote the report for colorectal cancer in module 3 (alongside hip

We're hosting a two day cadaveric course on lower limb trauma in Coventry. It is aimed at senior registrars and consultants.

Super proud of @AndyMetOrtho for delivering his excellent inaugural professor lecture today on his journey so far in orthopaedics and clinical trials! We’ll try not to break the lovely glass ornament, too. @WarwickCTU @warwickmed

Looking forward to presenting parts of my PhD alongside my examiner Jon Evans @jon_evans_uk Come along to find out all about current concepts of using PROMs to measure outcome. Might be a bit geeky!

Soooooooo excited to be the next EIC of @BoneJointRes!! Absolutely honored and can’t wait to get started! Get your Orthopaedic basic science research in #orthotwitter !! 🧫🧬🧪🔬🦴🩻🛠️🔩🪚🦾🦿

IMO, the result of the deal vote is actually less important than our cohesion afterwards. Whatever the result, the losing side needs to get on board with the resulting strategy, get involved in the union and continue to fight for FPR The future of the profession is at stake