The Hip disability and Osteoarthritis Outcome Score, Junior (HOOS JR.) and the Knee injury and Osteoarthritis Outcome Score, Junior (KOOS JR.) are new outcome reporting tools that were recently validated in 2015. They have been receiving a lot of interest from the orthopedic community as an efficient and reliable alternative to the longer Hip disability and Osteoarthritis Outcome Score (HOOS) and the Knee injury Osteoarthritis Outcome Score (KOOS) reporting tools.

The widely used HOOS and KOOS questionnaires which measure joint-specific pain and physical function contain 40 and 42 questions respectively. By contrast, the HOOS JR. has six questions and the KOOS JR. has seven.

The questions in the HOOS JR. and KOOS JR. are taken directly from their parent questionnaire and focus on the three categories of joint pain, stiffness and function in daily living instead of the five categories that the HOOS and KOOS focus on: pain, function in daily living, function in Sport and Recreation, other symptoms and knee-related Quality of Life.

The brevity of the HOOS and KOOS JR. survey allows for faster completion and greater patient engagement.



The main advantage of the HOOS and KOOS JR. is its significantly shortened length. With a completion time of under 3 minutes, it is an attractive alternative to the longer HOOS/ KOOS reporting tool.

The HOOS JR. and KOOS JR. have been validated by the HSS validation cohort and the FORCE-TJR registry. Internal consistency was found to be high for both the HOOS JR. and KOOS JR. and research suggested that there was near-perfect correlation with both the pain and activities of daily living/function domains of the full HOOS/KOOS and the WOMAC reporting tool (Spearman’s correlations 0.80-0.94).

Another advantage of the HOOS and KOOS JR. is that its scoring methodology is easier to apply than that of the HOOS/KOOS tool. In the new tools, patients rate each activity by indicating the amount of pain or disability they experience while carrying them out. Raw scores are added up (range 0-24 HOOS JR., range 0-28 KOOS JR.) and converted to an interval score (0-100) using an interval table. The interval score represents a patients total joint disability where 0 corresponds to total joint disability and 100 perfect joint health.

As a point of interest, at present no literature exists on whether a HOOS JR. or KOOS JR. outcome score can be derived from the score obtained in the full length HOOS and KOOS versions.



As a newly validated outcome tool there is very little literature at present about the HOOS and KOOS JR. Over time further studies and research should help provide a more complete picture about the robustness, reliability and viability of the HOOS JR. and KOOS JR. as outcome reporting tools.