An Article 6 violation means the setting aside of conviction and sentence
The decision in Dorigo v Italy (ECHR November 2000) set events in motion in Italy resulting in the position that any Article 6 violation found by the ECHR will result in the nullification of sentence and conviction. This applies to the present callunia case of Ms Knox and in any subsequent cases brought by Ms Knox and Mr Sollecito. Here is the short form of what happened:
The principle of "restitutio integrum" was reiterated in Council of Ministers Recommendation No.R(2000)2. This means that states found in violation of the convention are required as far as is possible, to put applicants back in the position they would have enjoyed had their rights not been violated.
https://wcd.coe.int/ViewDoc.jsp?id=334147&Site=CM
Subsequently, numerous resolutions were adopted by the CofM in connection with the Dorigo case. In particular, in ResDH(2004)13, the committe "strongly urged (that) the Italian authorities.... erase the consequences of the violation for the applicant in the case be adopted quickly."
http://caselaw.echr.globe24h.com/0/...-of-dorigo-against-italy-81277-33286-96.shtml
In 2006, the Bologna Appellate Court on application for review by Dorigo, questioned the constitutional legitimacy of domestic law (art 630 CCP), since it did not permit for the re-opening of proceedings following an ECHR decision. This court referred the matter to the Constitutional Court but at the same time suspended Dorigo's sentence and let him go.
The public prosecutor in Udine also referred the case back to the Court of Assises arguing that the continued detention of Dorigo was unlawful. When the application was rejected, he appealed it to the Court of Cassation, which set aside the rejection, also ordering Dorigo's immediate and unconditional release in decision 2800, stating:
"the judge...must declare the unenforeceability of the sentence if the ECtHR established that the conviction had been issued in violation of the right to a fair trial established by Art 6 ECHR"
At the Constitutional Court, Decision 129/2008 rejected consideration of the issue as raised by the Bologna Appellate Court, contending that as raised, it was a matter for the legislature to correct. However, following different argument at the appellate level, the issue of constitutionality was successfully raised to the Constitutional Court in connection with Article 117 of the constitution and Article 46 of the convention, which states that the contracting parties agree:
"to abide by the final judgement of the court in any case to which they are parties"
http://www3.unisi.it/dipec/palomar/italy015_2011.html#1
The response of the Constitutional Court was to declare Art 630 CCP unconstututional in decision 113/2011.
http://www.cortecostituzionale.it/actionSchedaPronuncia.do?anno=2011&numero=113
Thus, imprisoning or continuing to imprison an applicant after a finding by the ECHR of a violation of Article 6, is unlawful in Italy and the act itself a breach of Article 5 of the convention.
See also, Italian Constitution:
https://www.senato.it/documenti/repository/istituzione/costituzione_inglese.pdf
And the European Convention Human Rights:
http://www.echr.coe.int/Documents/Convention_ENG.pdf