Rotational Changes in the Tibia After High Tibial Valgus Osteotomy: A Comparative Study of Lateral Closing Versus Medial Opening Wedge Osteotomy

Background: After high tibial valgus osteotomy (HTO), rotational changes in the tibia may occur, which can affect the biomechanics of the patellofemoral joint and may lead to anterior knee pain. Purpose: To compare the rotational changes in the tibia between closing wedge HTO (CWHTO) and opening wedge HTO (OWHTO). Study Design: Cohort study; Level of evidence, 3. Methods: Among the patients who underwent HTO between May 2012 and August 2015, 53 (28 CWHTO and 25 OWHTO) who had computed tomography scans before and at 1 year after the HTO were included. The following parameters were compared between CWHTO and OWHTO: (1) tibial torsion angle, (2) knee rotation angle, and (3) tibial tuberosity–trochlear groove (TT-TG) distance. During the last follow-up, patients were asked to rate their anterior knee pain when climbing the stairs, using the visual analog scale. Results: The tibial torsion angle significantly decreased (internal rotation of the distal fragment) after CWHTO (mean ± SD, –2.1°± 4.1°; P = .019) and OWHTO (–1.8°± 3.3°; P = .029). The knee rotation angle significantly decreased (external rotation of the proximal fragment) after OWHTO (–1.8°± 3.4°; P = .039) but was not changed after CWHTO (0.1°± 3.1°; P = .859). The mean TT-TG distance significantly decreased after CWHTO (–3.1 ± 3.0 mm; P < .001) but increased after OWHTO (2.0 ± 4.3 mm; P = .012). At the final follow-up (minimum, 4 years), the visual analog scale pain score during stair climbing was significantly higher after OWHTO than after CWHTO (3.1 ± 1.4 vs 2.2 ± 1.3, P = .024). Conclusion: Internal rotation of the distal fragment occurred after both CWHTO and OWHTO. However, external rotation of the proximal fragment and increased TT-TG distance occurred after OWHTO. Because such rotational changes could affect anterior knee pain, further studies are warranted to investigate the definite relationship between tibial rotational changes and anterior knee pain after HTO.

High Tibial Valgus Osteotomy and Concomitant Anterior Cruciate Ligament Reconstruction. Which is the most appropriate surgical technique?

Introduction: The aim of this study is to evaluate advantages of close vs. open HTO of a group of patients who underwent a one-stage combined operation for chronic ACL rupture and early medial compartment arthritis. Material and Methods: We retrospective evaluated two series of patients operated on for anterior cruciate ligament (ACL) reconstruction combined with high tibial valgus osteotomy (HTO) for chronic anterior knee instability associated with medial tibio femoral osteoarthritis. Close HTO using rigid plate fixation and ACL reconstruction with bone patellar tendon bone graft was performed in Group A (7 patients). An open HTO using Puddu plate and ACL reconstruction with hamstring tendon graft was performed in Group B (9 patients). The mean age in Group A was 41 years old with an average varus of 8 degrees. Mean age in Group B was 42 years old and with 4 degrees of varus. Lysholm Score, HSS and Radiographs were performed. Results: Group A obtained a mean Lysholm score of 94, mean HSS of 91. Group B showed a mean Lysholm score of 83, mean HSS of 87. The mean follow-up was 5 years in both groups. In all cases osteotomies consolidated. Discussion: Technically we found that open HTO with hamstrings had several advantages such as lower risk of peroneal nerve injury, use of one incision, no problems as regards graft length, possibility of fixing the graft in the proximal tibia, maintenance of tibial slope and preservation of bone stock. The Open HTO need of osseous graft, may produce patella baja and the risk of nonunion is higher. This technique is indicated for relaxed medial collateral ligament. As regards the Close HTO there may be possibilities of a peroneal nerve injury, it may decrease the tibial slope, patellar ascent, loss of bone, the need to disrupt either the fibula or proximal tibio-fibular joint and may generate instability in the posterolateral corner and the screws could compromise the tunnels path. The advantages are provision of bone to bone contact with excellent union rates and the potential for full early weight-bearing. Conclusion: In spite of these issues, both procedures relieved pain and restored knee stability and the choice will depend on each particular case.

Pre-Operative Bone Marrow-Derived Cell Mobilization by G-CSF Enhances Osseointegration of Bone Substitute In Patients Undergoing Surgery with High Tibial Valgus Osteotomy

Abstract 4773 Introduction. Bone substitutes are widely used to improve bone repair in orthopaedic surgical procedures. Osseointegration is a slow process that takes place both at bone-implant interface and inside the tridimensional structure. The process might benefit from the addition of bone marrow-derived cells (BMC). In order to exploit this possible effects, a study protocol has been designed including preoperative BMC mobilization induced by granulocyte-colony stimulating factor (G-CSF). Aim of the study was to verify feasibility, safety and efficacy of BMC-mobilization in patients undergoing high tibial valgus osteotomy (HTVO). Patients and Methods. Overall, 24 patients undergoing medial open wedge HTVO to treat genu varum were enrolled in a prospective phase II trial. The osteotomy gap was filled by hydroxyapatite and tricalciumphosphate bone graft substitute. Two consecutive cohorts of 12 patients were assigned to receive (GROUP A) or not receive (GROUP B) a daily dose of 10 μ g/kg of G-CSF for 3 consecutive days, with an additional dose 4 hours before surgery. BMC mobilization was monitored by White Blood Cell (WBC) count and flow cytometry analysis of circulating CD34+ cells. All patients underwent a clinical (Lysholm Score and SF-36) and X-ray evaluation preoperatively, and at 1, 3 and 6 months after surgery. Anteroposterior standard radiographs were analysed to compare bone structure of the osteotomy areas. The percentage of integration at the interface between host bone and bone substitute (“host bone-substitute interface”) was estimated by 2 blinded observers. A computed tomography (CT) evaluation of the host bone-substitute interface was performed at 2 months. The osseointegration at the host bone-substitute interface was estimated through a semiquantitative score by 2 blinded observers and through a measure of bone density. Results. Patients of Groups A and B were well balanced in terms of age and clinical presentation. All patients of both groups completed the study. The most common adverse events among patients assigned to G-CSF were mild to moderate bone pain and muscle discomfort, well controlled by oral analgesics. There were no severe adverse events in both Group A and B, all patients are presently alive and well. Mobilization of CD34+ve cells occurred in all patients receiving G-CSF: mean preoperative WBC and CD34+ values were 39,09 × 103/μ l (21,57-51,11) and 131,58/ƒnμ l (29.1 - 404) in Group A, and 6,77 (2,8-12-06) and 7,67/μ l (5,4-12) in Group B, respectively. At the post-surgery clinical evaluation, patients of Group A experienced pain and a slight impairment in overall performance at 1 month assessment, whereas they displayed a slight increase in overall performance at 3 and 6 months compared to Group B. Semi-quantitative radiographic evaluation revealed a higher rate of bone substitute osseointegration in Group A than in Group B at 1, 3 and 6 months post-surgery. Also semiquantitative CT evaluation at 2 months showed an overall improved osseointegration at the host bone-substitute interface in Group A patients. Bone density was measured at the host bone-substitute interface by the Hounsfield score: Group A patients scored lower values at the upper interface compared to Group B, accordingly with advanced stage bone remodelling. The differences between Group A and B on assessment of host bone-substitute interface reached a statistical significance (p< 0,05). Bone mineral density at the host bone-substitute interface as measured with DEXA (Dual-energy X-ray absorptiometry), was lower, although without statistical significance, in Group A than in Group B, again suggesting a more advanced stage of bone remodelling in the treated group compared to controls. Conclusions. G-CSF administration given to induce pre-operative mobilization of bone marrow-derived cells: i. is feasible and safe in patients undergoing orthopaedic surgery; ii. allows the peripheral blood circulation of high numbers of CD34+ve cells; iii. may hasten bone graft substitute integration as suggested by both clinical and radiographical and CT evaluations. The enhanced osseointegration might be the result of a direct activity of G-CSF or of a cellular effect mediated by either hematopoietic or endothelial progenitors mobilized by G-CSF or by the combination of all these factors. Disclosures: No relevant conflicts of interest to declare.