{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T14:24:49Z","timestamp":1787754289769,"version":"build-2784847793"},"reference-count":12,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"2","license":[{"start":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T00:00:00Z","timestamp":1775001600000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"abstract":"<jats:sec>\n                    <jats:title>Case:<\/jats:title>\n                    <jats:p>A 39-year-old healthy woman without known genetic condition presented with bilateral patellar dislocations. Imaging demonstrated complete absence of the trochlear groove, defined as trochlear aplasia. Surgical treatment was initially performed on the left knee with refixation of an osteochondritis dissecans lesion, medial patellofemoral ligament reconstruction, and medializing tibial tubercle osteotomy. Intraoperative confirmation of the absence of trochlear groove made trochleoplasty unfeasible. At the 1-year follow-up, VAS was 0\/10 without patellar dislocation.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion:<\/jats:title>\n                    <jats:p>Trochlear aplasia represents an extreme form of trochlear dysplasia and poses diagnostic and surgical challenges because conventional measurements and trochleoplasty cannot be applied.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.2106\/jbjs.cc.25.00617","type":"journal-article","created":{"date-parts":[[2026,4,24]],"date-time":"2026-04-24T18:00:22Z","timestamp":1777053622000},"update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":0,"title":["Complete Trochlear Aplasia in the Knee\u2014An Extreme Form of Trochlear Dysplasia"],"prefix":"10.2106","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-3117-1287","authenticated-orcid":false,"given":"Valentine","family":"Schneebeli","sequence":"first","affiliation":[{"name":"Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8128-3927","authenticated-orcid":false,"given":"Lukas","family":"Jud","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8526-6032","authenticated-orcid":false,"given":"Lazaros","family":"Vlachopoulos","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2993-7537","authenticated-orcid":false,"given":"Sandro F","family":"Fucentese","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2026,4]]},"reference":[{"key":"bib1-20260424","first-page":"1466","article-title":"Pain and patellar instability classification","volume":"56","author":"Dejour","year":"1998","journal-title":"Med Hyg."},{"issue":"5","key":"bib2-20260424","doi-asserted-by":"crossref","first-page":"807","DOI":"10.1302\/0301-620X.76B5.8083274","article-title":"The femoral sulcus in children. An ultrasonographic study","volume":"76","author":"Nietosvaara","year":"1994","journal-title":"J Bone Joint Surg Br."},{"issue":"3","key":"bib3-20260424","doi-asserted-by":"crossref","first-page":"405","DOI":"10.2106\/00004623-198668030-00014","article-title":"Instability of the patellofemoral joint in Down syndrome","volume":"68","author":"Dugdale","year":"1986","journal-title":"J Bone Joint Surg Am."},{"issue":"1","key":"bib4-20260424","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1007\/BF01552649","article-title":"Factors of patellar instability: an anatomic radiographic study","volume":"2","author":"Dejour","year":"1994","journal-title":"Knee Surg Sports Traumatol Arthrosc."},{"key":"bib5-20260424","first-page":"425","article-title":"Aplasia of the trochlea in uniovular twins and in a case with palsy of the ulnar nerve","volume":"8","author":"Moriwaki","year":"1977","journal-title":"Kanto J Orthop Trauma."},{"issue":"2","key":"bib6-20260424","doi-asserted-by":"crossref","first-page":"582","DOI":"10.1148\/radiology.216.2.r00au07582","article-title":"Patellar instability: assessment on MR images by measuring the lateral trochlear inclination-initial experience","volume":"216","author":"Carrillon","year":"2000","journal-title":"Radiology."},{"issue":"8","key":"bib7-20260424","doi-asserted-by":"crossref","first-page":"2833","DOI":"10.1002\/ksa.12539","article-title":"Adapting the dejour classification of trochlear dysplasia from qualitative radiograph\u2010 and CT\u2010based assessments to quantitative MRI\u2010based measurements","volume":"33","author":"Dejour","year":"2025","journal-title":"Knee Surg Sports Traumatol Arthrosc."},{"issue":"1","key":"bib8-20260424","doi-asserted-by":"crossref","first-page":"8","DOI":"10.5435\/00124635-201101000-00002","article-title":"The role of trochlear dysplasia in patellofemoral instability","volume":"19","author":"Bollier","year":"2011","journal-title":"J Am Acad Orthop Surg."},{"key":"bib9-20260424","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1186\/1750-1172-2-27","article-title":"Ellis-van Creveld syndrome","volume":"2","author":"Baujat","year":"2007","journal-title":"Orphanet J Rare Dis."},{"issue":"2","key":"bib10-20260424","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1159\/000324105","article-title":"Short stature due to SHOX deficiency: genotype, phenotype, and therapy","volume":"75","author":"Binder","year":"2011","journal-title":"Horm Res Paediatr."},{"issue":"5","key":"bib11-20260424","doi-asserted-by":"crossref","first-page":"1179","DOI":"10.1002\/ksa.12151","article-title":"Increased tibial tuberosity torsion has the greatest predictive value in patients with patellofemoral instability compared to other commonly assessed parameters","volume":"32","author":"Jud","year":"2024","journal-title":"Knee Surg Sports Traumatol Arthrosc."},{"issue":"7","key":"bib12-20260424","doi-asserted-by":"crossref","first-page":"103035","DOI":"10.1016\/j.otsr.2021.103035","article-title":"Complications and outcomes of trochleoplasty for patellofemoral instability: a systematic review and meta-analysis of 1000 trochleoplasties","volume":"107","author":"Leclerc","year":"2021","journal-title":"Orthop Traumatol Surg Res."}],"container-title":["JBJS Case Connector"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ovid.com\/10.2106\/JBJS.CC.25.00617","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T13:25:16Z","timestamp":1787750716000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ovid.com\/10.2106\/JBJS.CC.25.00617"}},"subtitle":["A Case Report"],"short-title":[],"issued":{"date-parts":[[2026,4]]},"references-count":12,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026]]}},"URL":"https:\/\/doi.org\/10.2106\/jbjs.cc.25.00617","relation":{},"ISSN":["2160-3251"],"issn-type":[{"value":"2160-3251","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4]]}}}