{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,20]],"date-time":"2026-09-20T20:55:21Z","timestamp":1789937721552,"version":"4.0.1"},"reference-count":23,"publisher":"Wiley","issue":"12","license":[{"start":{"date-parts":[[2012,1,26]],"date-time":"2012-01-26T00:00:00Z","timestamp":1327536000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Knee surg. sports traumatol. arthrosc."],"published-print":{"date-parts":[[2012,12]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Purpose<\/jats:title><jats:p>The quadriceps angle (Q\u2010angle) represents the angle between the vector of action of the quadriceps and the patellar tendon. An increased Q\u2010angle has been associated with an increased risk of patellar instability, although there is disagreement on its reliability and validity as it is affected by the position of the limb and contraction of the quadriceps. Tibial tuberosity\u2013trochlear groove distance (TT\u2013TG) is ascertained by axial CT scanning, with an increased value associated with patellar instability. This study aimed to determine whether the Q\u2010angle correlates with the TT\u2013TG distance in patients with patellar instability.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Q\u2010angles were measured in 34\u00a0knees that had previously undergone CT scanning for assessment of patellar instability. Measurements were made with the patient supine, the knee extended and the lower limbs in neutral rotation with the quadriceps relaxed and contracted. TT\u2013TG distance was measured on CT scanning in an identical position.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Of the 34\u00a0knees measured, 24 had symptoms of patellar instability, and 10 were normal. A significant <jats:italic>negative<\/jats:italic> correlation between relaxed Q\u2010angle and TT\u2013TG in all knees was demonstrated (<jats:italic>p<\/jats:italic> = 0.028). In symptomatic knees, contracted Q\u2010angle also demonstrated a significant <jats:italic>negative<\/jats:italic> correlation with TT\u2013TG (<jats:italic>p<\/jats:italic> = 0.037).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>If TT\u2013TG distance is regarded as the gold standard measurement, Q\u2010angle is not a reliable indicator of patellar instability. There is a clear need to develop methods to more fully characterise the knee and factors contributing to patellar instability.<\/jats:p><\/jats:sec><jats:sec><jats:title>Level of evidence<\/jats:title><jats:p>II.<\/jats:p><\/jats:sec>","DOI":"10.1007\/s00167-012-1907-8","type":"journal-article","created":{"date-parts":[[2012,1,25]],"date-time":"2012-01-25T07:28:17Z","timestamp":1327476497000},"page":"2399-2404","source":"Crossref","is-referenced-by-count":55,"title":["The relationship between quadriceps angle and tibial tuberosity\u2013trochlear groove distance in patients with patellar instability"],"prefix":"10.1002","volume":"20","author":[{"given":"A. D.","family":"Cooney","sequence":"first","affiliation":[{"name":"<!--<label>1<\/label>--> Queen Elizabeth Hospital NE9 6SX Gateshead Tyne and Wear UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Z.","family":"Kazi","sequence":"additional","affiliation":[{"name":"<!--<label>1<\/label>--> Queen Elizabeth Hospital NE9 6SX Gateshead Tyne and Wear UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"N.","family":"Caplan","sequence":"additional","affiliation":[{"name":"<!--<label>2<\/label>--> School of Life Sciences Northumbria University NE1 8ST Newcastle upon Tyne UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M.","family":"Newby","sequence":"additional","affiliation":[{"name":"<!--<label>1<\/label>--> Queen Elizabeth Hospital NE9 6SX Gateshead Tyne and Wear UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A.","family":"St Clair Gibson","sequence":"additional","affiliation":[{"name":"<!--<label>2<\/label>--> School of Life Sciences Northumbria University NE1 8ST Newcastle upon Tyne UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"D. 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