{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T22:13:30Z","timestamp":1778624010545,"version":"3.51.4"},"reference-count":29,"publisher":"Wiley","issue":"12","license":[{"start":{"date-parts":[[2018,6,4]],"date-time":"2018-06-04T00:00:00Z","timestamp":1528070400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2018,6,4]],"date-time":"2018-06-04T00:00:00Z","timestamp":1528070400000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/www.springer.com\/tdm"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Knee surg. sports traumatol. arthrosc."],"published-print":{"date-parts":[[2018,12]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Purpose<\/jats:title><jats:p>Valgus deformities of the lower extremity influence patellofemoral joint kinematics. However, studies examining the clinical outcome after treatment of patellar instability and maltracking due to valgus deformity are rare in recent literature. This study\u2019s purpose is to analyze the clinical results after combined distal femoral osteotomy (DFO) for treatment of patellar instability.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>From 2010 to 2016, 406 cases of patellofemoral instability and maltracking were treated. Twenty cases of recurring (\u2265\u20092) patellar dislocations with genu valgum and unsuccessful conservative treatment were included in the study. A radiological analysis was performed, and anteroposterior (AP), lateral and long leg standing radiographs were analyzed, and the leg axis was pre\u2010 and postoperatively measured. At least 12\u00a0months postoperatively, the clinical leg axis, range of motion (ROM), apprehension sign, Zohlen sign, and J\u2010sign were physically examined. Pain level and knee function were objectified on a visual analogue scale (VAS). The Lysholm, Kujala, and Tegner scores, re\u2010dislocation rate, and patient satisfaction were also examined.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>20 combined DFOs on 18 patients with a median age of 23 years (15\u201355 years) were performed. The preoperative mechanical leg axis was 6.5\u00b0\u2009\u00b1\u20092.0\u00b0 valgus, and the mean tibial tuberosity to trochlear groove (TT\u2010TG) distance was 19.1\u2009\u00b1\u20094.8\u00a0mm. All patients reported multiple dislocations. Intraoperatively, 71% presented III\u00b0\u2013IV\u00b0 cartilage lesions, located retropatellarly in 87% and correlating negatively with the postoperative Lysholm score (<jats:italic>r<\/jats:italic>\u2009=\u2009\u2212\u20090.462, <jats:italic>p<\/jats:italic>\u2009=\u20090.040). The leg axis was corrected by 7.1\u00b0\u2009\u00b1\u20092.6\u00b0, and in 17 cases, the tibial tubercle was additionally medialized by 10\u2009\u00b1\u20093.1\u00a0mm. All patellae were re\u2010stabilized with medial patellofemoral ligament reconstruction. After a median period of 16 (12\u201364) months, the pain level decreased from 8.0\u2009\u00b1\u20091.4 to 2.3\u2009\u00b1\u20092.1 (VAS <jats:italic>p<\/jats:italic>\u2009\u2264\u20090.001) and knee function improved from 40.1\u2009\u00b1\u200917.9 to 78.5\u2009\u00b1\u200916.6 (Kujala <jats:italic>p<\/jats:italic>\u2009\u2264\u20090.001), 36.1\u2009\u00b1\u200919.5 to 81.6\u2009\u00b1\u200911.7 (Lysholm <jats:italic>p<\/jats:italic>\u2009\u2264\u20090.001), and 2.0 (1\u20135) to 4.0 (3\u20136) (median Tegner <jats:italic>p<\/jats:italic>\u2009\u2264\u20090.001). No re\u2010dislocation was observed.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Combined DFO is a suitable treatment for patellar instability and maltracking due to genu valgum, as it leads to very low re\u2010dislocation rates, a significant reduction of pain, and a significant increase of knee function with good\u2010to\u2010excellent results in the short\u2010term follow\u2010up. However, a high prevalence of substantial cartilage lesions is observed, causing postoperative limitations of knee function.<\/jats:p><\/jats:sec><jats:sec><jats:title>Level of evidence<\/jats:title><jats:p>IV, retrospective cohort study.<\/jats:p><\/jats:sec>","DOI":"10.1007\/s00167-018-5000-9","type":"journal-article","created":{"date-parts":[[2018,6,4]],"date-time":"2018-06-04T08:23:09Z","timestamp":1528100589000},"page":"3572-3581","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":82,"title":["Combined distal femoral osteotomy (DFO) in genu valgum leads to reliable patellar stabilization and an improvement in knee function"],"prefix":"10.1002","volume":"26","author":[{"given":"Jannik","family":"Frings","sequence":"first","affiliation":[{"name":"<!--<label>1<\/label>--> Chirurgisch\u2010Traumatologisches Zentrum, Asklepios Klinik St. Georg Lohm\u00fchlenstr. 5 20099 Hamburg Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Matthias","family":"Krause","sequence":"additional","affiliation":[{"name":"<!--<label>1<\/label>--> Chirurgisch\u2010Traumatologisches Zentrum, Asklepios Klinik St. Georg Lohm\u00fchlenstr. 5 20099 Hamburg Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ralph","family":"Akoto","sequence":"additional","affiliation":[{"name":"<!--<label>1<\/label>--> Chirurgisch\u2010Traumatologisches Zentrum, Asklepios Klinik St. Georg Lohm\u00fchlenstr. 5 20099 Hamburg Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter","family":"Wohlmuth","sequence":"additional","affiliation":[{"name":"<!--<label>1<\/label>--> Chirurgisch\u2010Traumatologisches Zentrum, Asklepios Klinik St. Georg Lohm\u00fchlenstr. 5 20099 Hamburg Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Karl\u2010Heinz","family":"Frosch","sequence":"additional","affiliation":[{"name":"<!--<label>1<\/label>--> Chirurgisch\u2010Traumatologisches Zentrum, Asklepios Klinik St. Georg Lohm\u00fchlenstr. 5 20099 Hamburg 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