A bicompartmental or bicondylar knee prosthesis adapted to be fixed to a femur, the prosthesis comprising a medial portion adapted to define at least part of a medial femoral condyle; a lateral portion adapted to define at least part of a lateral femoral condyle; an interconnecting portion which integrally connects the medial portion and the lateral portion to each other; the prosthesis being shaped so as to be adapted to leave the native trochlea at least partially uncovered; wherein said medial portion and said lateral portion of the prosthesis comprise a respective posterior end part ; said posterior end parts being destined to be posterior parts of the prosthesis , when it is implanted and the knee is in extension; wherein the medial portion and the lateral portion comprise a respective anterior end part , destined to be anterior parts of the prosthesis , when it is implanted and the knee is in extension; wherein the posterior end part of the medial portion has a posterior end and the posterior end part of the lateral portion has a posterior end ; wherein the anterior end part of the medial portion has an anterior end and the anterior end part of the lateral portion has an anterior end ; characterized in that , along a same axis (X), a length (d1) of the medial portion is greater than a length (d2) of the lateral portion , so that when the prosthesis is implanted said anterior end of the lateral portion is more distal than said anterior end of the medial portion ; said axis (X) being an axis perpendicular to a tangent (t0) to an outer surface of each of said posterior end parts , and perpendicular to tangents (t1, t2) to the anterior end of the medial portion and of the lateral portion , respectively. a medial portion adapted to define at least part of a medial femoral condyle; a lateral portion adapted to define at least part of a lateral femoral condyle; an interconnecting portion which integrally connects the medial portion and the lateral portion to each other; the prosthesis being shaped so as to be adapted to leave the native trochlea at least partially uncovered; wherein said medial portion and said lateral portion of the prosthesis comprise a respective posterior end part ; said posterior end parts being destined to be posterior parts of the prosthesis , when it is implanted and the knee is in extension; wherein the medial portion and the lateral portion comprise a respective anterior end part , destined to be anterior parts of the prosthesis , when it is implanted and the knee is in extension; wherein the posterior end part of the medial portion has a posterior end and the posterior end part of the lateral portion has a posterior end ; wherein the anterior end part of the medial portion has an anterior end and the anterior end part of the lateral portion has an anterior end ; characterized in that , along a same axis (X), a length (d1) of the medial portion is greater than a length (d2) of the lateral portion , so that when the prosthesis is implanted said anterior end of the lateral portion is more distal than said anterior end of the medial portion ; said axis (X) being an axis perpendicular to a tangent (t0) to an outer surface of each of said posterior end parts , and perpendicular to tangents (t1, t2) to the anterior end of the medial portion and of the lateral portion , respectively. <EOS>