Several surgical treatment options are available in case of ACL injury and mild OA: anterior cruciate ligament reconstruction, isolated coronal plane realignment osteotomy, or in association with ACL graft, deflection osteotomy, and possible associated meniscal transplantation with ACL reconstruction. Evaluation of the patient and knee history is essential for surgical decision-making. The following parameters are relevant for indication: the patient’s functional objectives, knee laxity evaluation, predominant symptom (pain, instability or both), meniscal status, and X-ray evaluation including long-leg axis.

The objectives of chronic anterior laxity treatment are:

Several situations can arise depending on the Dejour laxity classification [1]. We summarized this classification and the therapeutic options in an algorithm (Fig. 43.1). According to the stage of osteoarthritis, treatment is based on a valgus or deflection osteotomy. Both corrections are sometimes combined, but one of the two correction planes must be favored over the other. Indication for osteotomy is malalignment with symptomatic osteoarthritis in the overloaded compartment. The analysis of alignment in both planes is essential (long-leg axis, measuring the tibial slope) for planning tibial osteotomy (frontal or coronal plane).

In the ACL-deficient knee with varus deformity, the biomechanical and surgical objective is to restore overcorrection to 3° of mechanical valgus, if ACL reconstruction is combined with HTO. Correction of the tibial slope may be proposed if anterior or posterior tibial translation is excessive or associated with a correction in the frontal plane.

In patients with a painful and unstable ACL-deficient knee with varus deformity, combined surgery including ACL reconstruction and HTO represents an interesting salvage procedure for such complex patients who are usually young and desire improvement in both their stability and pain (47 Chatain).

In the recent literature, only 21 publications of combined HTO and ACL reconstruction (either at the same stage or separately) have been published [42]. The main characteristics of the papers are summarized in Table 43.2. The number of patient in each series is very low from 5 to 51 cases, compared to the number of isolated ACL reconstruction during the same period. In most cases, these young patients (20–25 years old) were sportsmen and often competitors. Many had chronic anterior laxity with a former long delay between injury and surgery (more than 10 years). They also present severe cartilage damage, and during this period, a medial meniscectomy was very frequently observed from 56 to 100 % of medial meniscectomy. Zaffagnini [21] also report a high frequency of previous ACL reconstruction (40 %). The mean age of this study was 40.1 years; and was older than in other previous studies and the mean delay from injury to injury was longer 10.4 ± 8.1 years.

At the time of surgery, patients were active but present both knee pain and knee instability as objective by the instrumental laxity measurement. The main symptoms for indications were instability and medial pain. Radiographically, there was prearthritic change in most of the patients with joint space narrowing less than 50 %. There was a varus deformity with a global hip knee angle in varus (3.8 + 2.7° for Zaffagnini [21], 3° for Bonin [22, 23]. The results are interesting with low morbidity and low failure rate at femoral follow-up. With a mean 6.5 years of follow-up, the failure rate was 6 % for Zaffagnini [21] and two cases of stiffness for Bonin [22, 23]. For the ACL reconstruction, it was both intra-articular graft, and in some situation an extra-articular tenodesis was added to better pivot shift control. However, with the small number available, no statistical significant difference could be shown. An ACL procedure could be associated simultaneously as described by Elser [24]. Clinically, patients are satisfied or very satisfied in 80–90 % of cases. A significant number of active patients were able to resume sportive activity moderate (44–47 %) [7, 21–23]. Knee stability was found to be associated with improved symptoms of pain [10, 11, 22, 23, 25, 26]. Factors associated with limitations in return to sports activities were long term between initial injury and surgery, multiple procedures, cartilage lesion, and residual laxity greater than 10 mm [27].

Pain relief was predictable (55–64 % of cases). The instability is well controlled: 78–90 % of negative Lachman and 88–96 % of negative pivot shift. For Bonin [22, 23], the overall results are significantly related to the importance of preoperative tibial translation and revision. At final revision some patients still had relevant anterior laxity (27 % grade C for Bonin [22, 23], 2 for Zaffagnini [21]).

Radiographically, the midterm (4–5 years) evolution of OA medial femorotibial compartment was stabilized. At 8.5 years, Zaffagnini [21] found only one increase of one case for grade C compared to the preop level (18 versus 17). This inhibitory effect on the evolution OA is sustainable beyond 10 years. Bonin [22, 23] reviewed the patients 11 years later in the same group as Dejour [10] found only five cases of aggravation of class (17 %).