Scoring the BPII 2.0
The BPII is scored out of 100.
The VAS outputs are measured in millimetres for each question and summed. The sum is then divided by the number of questions that are answered.
If all questions answered at the highest possible QOL of 100mm, then the sum of the VAS measures is 2300.
The BPII score will be 2300/23 = 100/100.
Based on an analysis of BPII scores, a minimum of 19/23 questions needs to be completed for the score to be considered valid.
If a patient does not answer between one and four questions, these unanswered questions are subtracted from the denominator.
In our cohort of over 800 patients, the average pre-operative BPII score of patients who undergo a patellofemoral stabilization procedure is 23/100.