The results of corrective osteotomy for valgus arthritic knees

Surgical Technique and Preliminary Outcomes of Double-Level Osteotomy for Valgus Deformity

Background

Data are limited regarding the surgical technique or outcomes of double-level osteotomy (DLO) combining medial closing-wedge distal femoral osteotomy and medial closing-wedge high tibial osteotomy in patients with moderate-to-severe valgus deformity.

Purpose/Hypothesis

To describe the surgical technique and assess the short-term outcomes and surgical accuracy of DLO in patients with a moderate or severe valgus deformity. It was hypothesized that this technique would result in good clinical outcomes with precise deformity correction.

Study Design

Case series; Level of evidence, 4.

Methods

Eight patients (mean age, 44.2 ± 10.9 years) with a moderate or severe valgus knee treated with DLO (9 knees; mechanical tibiofemoral angle [mTFA], 10.3°± 3.5°) were included. The mean follow-up was 25.1 ± 11.1 months. Preoperative to postoperative changes in radiographic parameters (mTFA, mechanical lateral distal femoral angle, mechanical medial proximal tibial angle, joint line convergence angle) and clinical scores (Hospital for Special Surgery score, Oxford Knee Score, Lysholm score) were assessed. Surgical accuracy was calculated by subtracting the achieved postoperative correction from the preoperatively planned targeted correction.

Results

The mTFA changed significantly from 10.3°± 3.5° preoperatively to -1.8°± 3.4° postoperatively (P < .001); the mechanical lateral distal femoral angle and mechanical medial proximal tibial angle changed significantly by 5.1°± 2.7° and 5.9°± 2.2°, respectively (P < .001 for both); and the posterior distal femoral angle decreased significantly from 85.9°± 3.1° to 84.2°± 2.4° (P < .01). There was no significant difference between pre- and postoperative joint line convergence angles (3.3°± 2.3° to 2.6°± 2.1°). The accuracy of the correction was high: the mTFA achieved postoperatively differed from the mTFA planned preoperatively by a mean of 2.7°± 1.9° (range, 0.6°-6.6°). Significant pre- to postoperative improvement was seen for all outcome scores (Hospital for Special Surgery, from 67 ± 11 to 93 ± 4; Oxford Knee Score, from 29 ± 7 to 43 ± 3; Lysholm, from 41 ± 24 to 89 ± 8; P < .001 for all).

Conclusion

High surgical accuracy was achieved, and patients who underwent varus DLO for valgus knees showed improved knee function at short-term follow-up. Varus DLO can be a surgical option to restore the optimal alignment and joint line obliquity in patients with moderate or severe valgus malalignment.

Morphological analysis of the distal femur as a surgical reference in biplane distal femoral osteotomy

Distal femoral osteotomy (DFO) is performed alone or with high tibial osteotomy (HTO) for patients with osteoarthritis and distal femur deformities. DFO is technically demanding, particularly when creating an anterior flange. Herein, we examined the morphological characteristics of the distal femur based on the cortical shape as a surgical reference for biplanar DFO. Computed tomography images of 50 valgus and 50 varus knees of patients who underwent biplanar DFO or total knee arthroplasty were analyzed. Axial slices at the initial level of the transverse osteotomy in the DFO and slices 10 mm proximal and 10 mm distal to that level were selected. The medial and lateral cortical angles and heights (MCLA, LCLA, MCH, and LCH) were measured on axial slices. Statistical comparisons were performed between the medial and lateral cortices and valgus and varus knees. MCLA and MCH were significantly smaller and lower, respectively, than LCLA and LCH (P < 0.01). The MCLA and MCH of varus knees were significantly smaller and lower, respectively, than those of valgus knees (P < 0.01). Surgeons should carefully observe morphological differences in the distal femur cortex, distinguishing between medial and lateral knees and varus and valgus knees during the creation of the anterior flange in the DFO.

Deformity in valgus knee malalignment is not only in the femur but also in tibia or both, based on demographic and morphological analysis before and after knee osteotomies

PURPOSE

This study aims to identify the demographic and morphological features of valgus knee deformity with unilateral osteoarthritic knee in the coronal plane. A secondary aim was to identify the distinct phenotypes of valgus knees in Hirschmann's phenotype and the coronal plane alignment of the knee (CPAK) classifications before and after a knee osteotomy (KO).

METHODS

A total of 107 patients (57 female and 50 male) with a mean age of 42.4 ± 17.2 years, who underwent varisation osteotomy for symptomatic unilateral knee osteoarthritis (OA) and constitutional valgus deformity, were enrolled in the study, and the mean follow-up period was 29.1 ± 7.3 months. The included cases comprised 60 cases of distal femoral osteotomy, 10 cases of double-level osteotomy and 33 cases of high tibial osteotomy. All patients underwent preoperative and postoperative clinical, functional and radiological evaluations, analysed by analysis of variance tests.

RESULTS

An analysis of the location of the valgus deformities demonstrated that 56 cases (52.3%) were femoral based, 18 cases (16.8%) were both femoral and tibial based and 33 cases (30.9%) were tibial based. Twelve preosteotomy cases (11.2%) and 38 postosteotomy cases (35.5%) matched the most common eight Hirschmann's phenotypes, phenotyping the coronal lower limb alignment based on the native alignment in young patients without OA. Four (3.7%) preosteotomy cases and 89 postosteotomy cases (83.1%) matched the most common three CPAK phenotypes (Ⅰ, Ⅱ, Ⅴ) based on constitutional alignment and joint line obliquity in healthy and osteoarthritic knees.

CONCLUSION

In valgus knee malalignment, the location of the deformity is not only solely femoral-based but also solely tibial-based or combined femoral and tibial-based. An individualised osteotomy approach would be recommended to achieve careful preoperative planning that considers the location of the deformity and the resultant joint line. Hirschmann's and CPAK classification would not be relevant when KO is considered.

LEVEL OF EVIDENCE

Level Ⅳ, retrospective case-control study.

Double-level knee osteotomy accurately corrects lower limb deformity and provides satisfactory functional outcomes in bifocal (femur and tibia) valgus malaligned knees

PURPOSE

Double-level knee osteotomy (DLO) is a challenging procedure that requires precision in preoperative planning and intraoperative execution to achieve the desired correction. It is indicated in cases of severe varus or valgus deformities where a single-level osteotomy would yield significantly tilted joint line obliquity (JLO). This study aimed to evaluate the effectiveness of DLO in achieving accurate correction without compromising JLO, using patient-specific cutting guides (PSCGs), in cases of bifocal valgus maligned knees.

METHODS

A single-centre, retrospective analysis of prospectively collected data for a total of 26 patients, who underwent DLO by PSCGs for valgus malaligned knees, between 2015 and 2020. Post-operative alignment was evaluated and the delta for different lower limb0.05, not statistically significant (ns)). All KOOS subs alignment parameters was calculated; the hip-knee-ankle angle (ΔHKA), medial proximal tibial angle (ΔMPTA), and lateral distal femoral angle (ΔLDFA). At the two-year follow-up, changes in the KOOS sub-scores, UCLA scores, lower limb discrepancy (LLD), and mean time to return to work and sport were recorded. All intraoperative and postoperative complications were recorded. The Mann-Whitney U test with a 95% confidence interval (95% CI) was used to evaluate the differences between two variables; one-way ANOVA between more than two variables and the paired Student's t-test was used to estimate the evolution of functional outcomes.

RESULTS

The postoperative mean ΔHKA was 0.9 ± 0.9°, the mean ΔMPTA was 0.7 ± 0.7°, and the mean ΔLDFA was 0.7 ± 0.8° (all values with p > 0.05, not statistically significant (ns)). All KOOS subscore's mean values were improved to an extent two-fold superior to the reported minimal clinically important difference (MCID) (all with p < 0.0001). There was a significant increase in the UCLA score at the final follow-up (5.4 ± 1.5 preoperatively versus 7.7 ± 1.4, p < 0.01). The mean time to return to sport and work was 4.7 ± 1.1 and 4.3 ± 2.1 months, respectively. There was an improvement in Lower-limb discrepancy preoperative (LLD = 1.3 ± 2 cm) to postoperative measures (LLD = 0.3 ± 0.4 cm), ns. Complications were 2 femoral hinge fractures, 2 deep vein thromboses, 1 delayed tibial healing, and 1 hardware removal for hamstring irritation syndrome.

CONCLUSION

DLO is effective and safe in achieving accurate correction in bifocal valgus malaligned knees with maintained lower limb length and low complication rate with no compromise of JLO.

LEVEL OF EVIDENCE

III.

Analysis of bone union after medial closing wedge distal femoral osteotomy using a new radiographic scoring system

INTRODUCTION

To compare bone union after medial closing wedge distal femoral osteotomy (MCWDFO) with that after lateral closing wedge distal femoral osteotomy (LCWDFO) using a novel scoring system.

MATERIALS AND METHODS

The data of 30 patients who received biplanar MCWDFO for valgus knees (MCWDFO group) were retrospectively examined and compared to that of 22 patients (25 knees) who underwent biplanar LCWDFO via a double-level osteotomy (DLO) for varus knees (LCWDFO group). The progression of bone union of the transverse osteotomy plane in the femur was assessed using a newly developed scoring system using radiographs taken immediately after surgery and 3 and 6 months postoperatively. The scoring system is based on a scale of zero to six points with higher scores indicating better bone union. The incidence of hinge fractures was assessed using CT images, and the rates of reoperation were evaluated using medical record data.

RESULTS

The mean bone union score was significantly lower in the MCWDFO group than in the LCWDFO group 3 months (2.1 ± 1.9 vs. 3.7 ± 1.7, P < 0.01) and 6 months (3.8 ± 2.1 vs 4.9 ± 1.5, P < 0.05) postoperatively. The incidence ratio of hinge fractures was significantly higher in the MCWDFO group than in the LCWDFO group (70.0% vs. 32.0%, P < 0.01). Two patients in the MCWDFO group underwent reoperation for delayed bone union or non-union.

CONCLUSION

Bone union progression was slower and hinge fractures were more frequently observed after MCWDFO than after LCWDFO via DLO. MCWDFO is technically challenging, and patients must be monitored closely during and after surgery.

Three-Dimensional Patient Specific Instrumentation and Cutting Guide for Medial Closing Wedge High Tibial Osteotomy to Correct Valgus Malalignment

Achievement of appropriate mechanical knee alignment is crucial to ensure optimal clinical outcomes following osteotomy procedures about the knee. The use of patient-specific instrumentation (PSI) to assist in preoperative planning and intraoperative realignment has gained increasing popularity. The purpose of this article is to describe a surgical technique involving a medial closing wedge high tibial osteotomy performed using three-dimensional (3D) PSI and cutting guide to revise residual valgus deformity following failed distal femoral osteotomy. The correction angle, 3D position of the hinge and wedge, as well as final plate and screw position are planned preoperatively using virtual software and computed tomography imaging to allow precise surgical execution.

Three-column subdivision for isolated posterolateral tibial plateau fractures and perspective surgical approaches

BACKGROUND

This study aimed (1) to introduce a computed tomography (CT)-based classification of the posterolateral compartment of the tibial plateau based on the fibula and to propose the individualized surgical approaches for each zone; and (2) to determine the surgical approach based on the classification, that would achieve a safe and effective reduction and could improve postoperative clinical outcomes.

METHODS

Eighteen cases of tibia plateau fracture involving the isolated posterolateral compartment in a single institution were retrospectively analyzed. The posterolateral compartment of the tibial plateau was segmented into three zones based on the fibular position and an individualized surgical approach was proposed for each zone. In anterior Zone I, surgical treatment was performed using an extended anterolateral approach and the patient was placed in the supine position; in middle Zone II, using the transfibular approach in the supine position; in posterior Zone III, using the posteromedial approach in the prone position.

RESULTS

In all cases, anatomical articular reduction (intra-articular step off in CT images <2 mm) was achieved and maintained for the follow up period. The average mechanical medial proximal tibial angle was increased from 87.6° before surgery to 88.2° in the immediate postoperative period (P = 0.060), and maintained for the follow up period (mean 89.9° at 1-year follow up). At the 1-year follow up, the knee range of motion averaged 140° and the Lysholm knee function score was 95.0 points.

CONCLUSION

An individualized surgical approach and fixation according to three-zone subdivision for isolated posterolateral tibial plateau fractures provided an effective and safe method to treat posterolateral tibial plateau fractures.

Change of limb alignment in Korean children and adolescents with idiopathic genu valgum

There has been no study evaluating the change of limb alignment for patients with genu valgum. The purpose of this study was to investigate the change of limb alignments in children and adolescents with idiopathic genu valgum through evaluating distal femur, proximal tibia, and knee joint line.Consecutive children and adolescents, under the age of 18, with genu valgum were included. Mechanical tibiofemoral angle, mechanical lateral distal femoral angle, mechanical medial proximal tibia angle, and joint line convergence angle were measured. The rate of changes for each radiographic measurement were analyzed using a linear mixed model.A total of 1539 teleroentgenograms from 518 limbs of 273 individuals were included in this study. Linear mixed model showed that the change of limb alignment was significantly associated with age, but not associated with gender and laterality. The mechanical tibiofemoral angle was most valgus initially, decreasing until reaching its lowest value of 2.8° at 10 years old. The mechanical lateral distal femoral angle decreases from initial neutral alignment and increases in valgus continuously. The mechanical medial proximal tibia angle decreases from initial valgus and progresses to be neutral at around the age of 10. The joint line convergence angle decreases sharply from initial valgus alignment to 0° at the age of 5.Valgus alignment in children with idiopathic genu valgum decreases until approximately the age of 10. In younger children, the tibia and joint line contribute most to overall valgus alignment; in older children, the femur contributes the most. Based on our results, we recommend monitoring patient limb alignment until it stabilizes around the age of 10, and then carefully planning and performing corrective surgery with complete consideration of the changing bony alignment.

Associations Between Periosteal Reaction of Proximal Tibial and Medial Compartment Knee Osteoarthritis

Objective

To evaluate and analyze the potential relationship between periosteal reaction and medial compartment knee osteoarthritis (KOA), and to assess the independent risk factors for the development of periosteal reaction associated with medial compartment KOA.

Methods

This is a retrospective comparative study. From January 2019 to December 2019 at the Third Hospital of Hebei Medical University, a total of 363 patients (726 knees) with medial compartment KOA were enrolled in this study according to our inclusion and exclusion criteria, including 91 males and 272 females, with an mean age of 57.9 ± 12.8 years (range, 18–82 years). Among these patients, 206 patients (412 knees) were allocated to the periosteal reaction group (44 males and 162 females) and 157 patients (314 knees) were allocated to the non‐periosteal reaction group (47 males and 110 females). The classification of KOA severity was based on Kellgren and Lawrence (K‐L) grading system. The malalignment of the lower extremities in coronal plane was evaluated as medial proximal tibial angle (MPTA), hip‐knee‐ankle angle (HKA), and lateral distal femoral angle (LDFA). Patients demographics and radiographic parameters were recorded in the two groups. Intra‐observer and inter‐observer reliabilities of all radiological measurements were analyzed by intraclass correlation coefficients (ICCs). Univariate analyses were conducted for comparison of differences with continuous variables between patients with periosteal reaction and without periosteal reaction. Multivariate logistical regression analysis was performed to determine the independent risk factors of radiographic parameters for periosteal reaction.

Results

The overall incidence of periosteal reaction associated with medial compartment KOA was 56.7%. Furthermore, we observed that the incidence of periosteal reaction significantly increased with age and correlated with K‐L grade progression (P < 0.05). There was a statistically significant difference between the two groups. In the multivariate logistical regression analysis, HKA and JLCA were identified as independent risk factors of the development of periosteal reaction in patients with medial compartment KOA (odds ratio [OR], 0.594; 95% confidence interval [CI] 0.544–0.648; P < 0.05; OR, 0.851; 95% confidence interval CI 0.737–0.983; P < 0.05; respectively), with other radiographic parameters including MTPA (OR 0.959; 95% CI 0.511–0.648; P > 0.05), LDFA (OR 0.990; 95% CI 0.899–1.089; P > 0.05), and JSW (OR 1.005; 95% CI 0.865–1.167; P > 0.05).

Conclusions

In this retrospective study, patients with lower HKA and higher JLCA were identified as independent risk factors for the development of periosteal reaction, which occurred most commonly adjacent to the lateral of proximal tibia diaphysis, and thus we concluded that periosteal reaction may be an anatomical adaptation for medial compartment KOA based upon these results.

Better functional results of opening wedge HTO for varus knees with medial osteoarthritis than opening wedge LFO for valgus knees with lateral osteoarthritis

Aims

To compare time dependent functional improvement for patients with medial, respectively lateral knee osteoarthritis (OA) after treatment with opening wedge osteotomy relieving the pressure on the osteoarthritic part of the knee.

Methods

In all, 49 patients (52 knees) with a mean age of 47 years (31 to 64) underwent high tibial osteotomies (HTO), and 24 patients with a mean age of 48 years (31 to 62) low femoral osteotomies (LFO) with opening wedge technique due to medial, respectively lateral knee OA with malalignment. All osteotomies were stabilized with a Puddu plate and bone grafting performed in the same time period (2000 to 2008). The patients were evaluated by the Knee Injury and Osteoarthritis Outcome Score (KOOS) pre-operatively and at six months, and at one, two, five, and ten years postoperatively. The knee OA was graded according to the Ahlbäck and Kellgren-Lawrence radiological scoring systems.

Results

The mean angular corrections were 8.0° (4° to 12°) for the HTO and 9.6° (4° to 20°) for the LFO. Both the pre-operative KOOS and the osteoarthritic gradings were similar for the two patient groups. The five subscores of KOOS increased significantly during the postoperative period (p < 0.001 to 0.029) levelling out after one year in both groups. The KOOS subscore symptoms was significantly higher for patients with HTO than those with LFO at all follow-up times, for sport and recreation in the period one to five years, and for pain and quality of life at two to five years (p < 0.001 to 0.009). Eight HTOs (15%) and five LFOs (21%) were converted to total knee arthroplasty after mean 6.7 years (2.0 to 9.8) and 5.4 years (4.0 to 8.0) respectively. The ten-year osteotomy survival rates were 88% for the HTO and 79% for the LFO (p = 0.745).

Conclusion

Patients with unicompartmental knee OA improved after a corrective opening wedge osteotomy, but four of the five subscores of KOOS were significantly higher for those with medial than those with lateral OA in most of the ten-year follow-up period.

Cite this article: Bone Joint Open 2020;1-7:346–354.

Medial closing wedge high tibial osteotomy for valgus tibial deformities: good clinical results and survival with a mean 4.5 years of follow-up in 113 patients

PURPOSE

A varus-producing medial closing wedge high tibial osteotomy (MCWHTO) is an uncommon procedure. The aim of this retrospective study was to assess the survivorship and prevalence of post-operative subjective knee laxity and satisfaction in a large cohort of patients with a MCWHTO performed without a MCL-reefing procedure.

METHODS

All patients (n = 176) who underwent a MCWHTO in our clinic between 2008 and 2016 were approached to participate. After review of patient charts, questionnaires were sent to willingly patients. Primary outcome was the survivorship of the MCWHTO; secondary outcome was patient-reported instability and satisfaction.

RESULTS

One-hundred and thirteen patients participated in the study. The 5-year survival rate of the MCWHTO was almost 80%. A total of 77% of the patients was satisfied with the treatment. With regard to post-operative subjective knee laxity, 26% of the patients experienced instability of the knee post-operation. Instability was significantly correlated with the KOOS domains, the Lysholm score, the IKDC knee function score and the Physical and Mental Health Domains of the SF-36.

CONCLUSION

Medial closing wedge high tibial osteotomy provides good results regarding survivorship and patient satisfaction for patients with a valgus deformity which is located in the proximal tibia. Clinically relevant is that in the surgical technique without MCL-reefplasty instability is significantly correlated with worse patient-reported outcome measures. The addition of a MCL reefing procedure will improve outcome in selected patients.

LEVEL OF EVIDENCE

III.

Cartilage regeneration in osteoarthritic knees treated with distal femoral osteotomy and intra-lesional implantation of allogenic human umbilical cord blood-derived mesenchymal stem cells: A report of two cases

BACKGROUND

To treat lateral compartment osteoarthritis caused by a valgus deformity, partial or total knee joint arthroplasty is recommended. However, for young patients, joint preservation surgery such as distal femoral osteotomy (DFO) can be an alternative treatment option. Combined cartilage defects of lateral compartment osteoarthritis can be restored by human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs). This case report presents the results of DFO and hUCB-MSC implantation for treating two patients with valgus deformity who had lateral compartment osteoarthritis.

CASE PRESENTATION

Two middle-aged patients with lateral compartment osteoarthritis and valgus deformity were treated using DFO and hUCB-MSC implantation. They recovered sufficiently to perform moderate exercise one year after surgery. The International Knee Documentation Committee, visual analog scale, and Western Ontario and McMaster Universities Osteoarthritis Index scores showed continuous improvement after surgery. Cartilage regeneration of International Cartilage Repair Society Grade 1, which was similar to normal, was observed in both patients through second-look arthroscopy. With time, the modified two-dimensional magnetic resonance observation of cartilage repair tissue scores also increased in both cases.

CONCLUSION

This is the first case report detailing the results of treating lateral compartment osteoarthritis using hUCB-MSCs and DFO. In conclusion, this can be considered a new treatment option for such cases.

Closing-Wedge Distal Femoral Osteotomies-Retrospective Study

Objective  To describe the surgical technique of distal closing-wedge femoral osteotomy and a cases series submitted to this technique.

Methods  A total of 26 patients submitted to medial closing-wedge distal femoral osteotomy from 2002 to 2013 were evaluated. All of the patients had their medical files and imaging exams reviewed to evaluate the degree of correction and their current state.

Results  Out of the 26 patients, 12 were male and 14 were female. Their mean age was 47.15 years old. In all of the cases, a neutral alignment related to the anatomical axis was achieved. Most of the patients presented bone healing at 6 weeks. There were no cases of bleeding during the surgery. One patient presented with delayed bone healing. One patient complained of plaque-related discomfort, requiring the removal of the device. One patient had a superficial infection, but no osteotomy revision was needed. There were no cases of deep venous thrombosis or of pulmonary thromboembolism. To date, there has been no conversion to total knee replacement.

Conclusion  Treatment with medial closing-wedge distal femoral osteotomy sustained the proposed correction in patients with up to 15 years of follow-up.

Radiological grading of osteoarthritis on Rosenberg view has a significant correlation with clinical outcomes after medial open-wedge high-tibial osteotomy

PURPOSE

To determine the classification scheme for osteoarthritis severity grading that most closely correlates with postoperative clinical outcomes and to identify the positive and negative prognostic factors for medial open-wedge high-tibial osteotomy (OWHTO).

METHODS

Seventy-nine consecutive patients with primary varus osteoarthritis were treated using OWHTO. Arthritic grading was determined by arthroscopic assessment according to the modified Outerbridge classification and by radiographic classification according to the Kellgren-Lawrence (KL) grading scale on standing anteroposterior (AP) and 45° posteroanterior (PA) flexion weight-bearing radiography. Clinical outcome was assessed using the Oxford Knee Score (OKS), which was evaluated both preoperatively and at the postoperative 2-year follow-up after OWHTO. Multivariate regression analyses were used to explore and quantify the influence of baseline patient demographics, variables related to arthroscopic and radiological grades of arthritis, as well as postoperative alignment changes on the OKS.

RESULTS

At the 2-year follow-up, the mean OKS had improved from 20 ± 4 to 39 ± 5 points (p < 0.001). The average mechanical femorotibial and mechanical medial proximal tibial angle (MPTA) changed from 6.9° ± 3.4° to valgus 2.7° ± 2.8° and from 85.6° ± 2.4° to 92.9° ± 3.7° (all p < 0.001). The osteoarthritis severity grade based on the KL scale was 2.4 ± 0.9 on standing AP radiography, 2.8 ± 0.9 on 45° PA flexion weight-bearing radiography (p = 0.003), and 3.4 ± 0.7 according to the modified Outerbridge classification. In the multivariate analyses, the KL grade on 45° PA flexion weight-bearing radiography (p = 0.01) and postoperative MPTA (p = 0.01) showed significant negative correlations with postoperative OKS at the 2-year follow-up.

CONCLUSION

The KL grading system based on 45° PA flexion weight-bearing radiography showed the strongest significant negative correlation with postoperative OKS after the OWHTO procedure using three different common OA classification schemes, which should be considered to determine the surgical indication of HTO. The KL grading system based on 45° PA flexion weight-bearing radiography showed the strongest correlation with high-tibial osteotomy-surgical indications and the counselling of patients with advanced osteoarthritis.

LEVEL OF EVIDENCE

IV.

Medial collateral ligament laxity in valgus knee deformity before and after medial closing wedge high tibial osteotomy measured with instrumented laxity measurements and patient reported outcome

INTRODUCTION

Medial closing wedge high tibial osteotomy (CWHTO) for valgus deformity correction was first described by Coventry whom performed an additional reefing of the medial collateral ligament (MCL) to prevent instability postoperative. In our clinic the additional reefing procedure has never been performed and instability has not been reported routinely by patients. Using instrumented laxity testing, pre- and postoperative valgus and varus knee laxity can be measured objectively. We hypothesize that absence of changes in laxity testing and subjective knee stability scores support that no additional reefing procedure is necessary.

MATERIALS AND METHODS

In a prospective cohort study 11 consecutive patients indicated for medial CWHTO were subjected to pre- and postoperative stress X-rays in 30° and 70° of flexion and opening of the joint line was measured in degrees on the radiographs. Patient reported outcome scores were documented with the KOOS, Lysholm, SF36, Oxford Knee Score and a VAS instability scoring tool.

RESULTS

All patients (7 females) completed the study, mean age was 46 years. Mean preoperative Hip Knee Ankle angle 6.4° valgus was corrected to mean postoperative alignment 0.1° valgus. A significant difference was measured between mean pre- and postoperative 30° valgus laxity (2.8° vs 5.3°, P = 0.005), 30° varus laxity (6.7° vs 3.2°, P = 0.005) and 70° valgus laxity (2.0° vs 4.8°, P = 0.008). Postoperative patient-reported knee instability as measured with the Lysholm questionnaire was significantly improved compared to preoperative instability (P = 0.006). VAS instability improved, but didn't reach significance (8.0 preoperative and 5.5 postoperative (P = 0.127). Other outcome measures showed improvement as well. No correlations between radiological findings and outcome scores were found.

CONCLUSION

A significant increase in postoperative valgus laxity in 30° and 70° of flexion deems reconsidering addition of MCL reefingplasty to the medial CWHTO although patient reported outcome on subjective stability scores fails to report increase of instability in this study population. Instrumented laxity measurements of medial CWHTO patients treated with additional medial reefingplasty should be performed to prove the value of this procedure.

Anatomic double-bundle medial patellofemoral ligament reconstruction with aperture fixation using an adjustable-length loop device: a 2-year follow-up study

Background

To assess the clinical availability of an adjustable-length loop device for use in the double-bundle technique with aperture fixation at the patella and femur during anatomic double-bundle medial patellofemoral ligament reconstruction (DB-MPFLR) for recurrent patellar dislocation.

Methods

We retrospectively investigated 11 patients (12 knees) with recurrent patellar dislocation who underwent anatomic DB-MPFLR with an ipsilateral semitendinosus tendon autograft. The graft was folded in half, and its central portion was hanged using the adjustable-length loop device. Both free ends of the graft were fixed at the proximal and distal ends of the medial edge of the patella by using suture anchors, and the hanged graft loop was pulled into the femoral tunnel while maintaining equal tension on both bundles. Manual traction of the suture loops was applied to fix the graft appropriately in full range of motion (ROM) of the knee joint under arthroscopic guidance. Clinical outcomes such as re-dislocation, ROM, clinical scores (Kujala score, Lysholm score, and visual analogue scale score for anterior knee pain), and complications were assessed preoperatively and at 2 years postoperatively. Radiographic parameters indicating patellar position, including congruence angle and lateral patellofemoral angle, were measured at 4 different angles of knee flexion (30°, 45°, 60°, and 90°).

Results

At 4 different flexion angles of the knee joint, the preoperative congruence angle decreased significantly and the lateral patellofemoral angle increased significantly at the final follow-up (P <  0.001). Notably, the improvements in these angles were maintained with no significant differences at the 4 different flexion angles. None of the patients experienced subluxation or re-dislocation after surgery. The patellar instability symptoms improved, as confirmed on the basis of radiographic and other clinical outcomes.

Conclusion

New DB technique with aperture fixation at the patella and femur by using an adjustable-length loop device offers high stability with full ROM of the knee joint, can be considered as a feasible procedure and technique for recurrent patellar dislocation.

Surgical Treatment With Closing-Wedge Distal Femoral Osteotomy for Recurrent Patellar Dislocation With Genu Valgum

BACKGROUND

Closing-wedge distal femoral osteotomy (CWDFO)-combined with medial reefing and lateral release, if necessary- has been used to treat recurrent patellar dislocation (RPD) with genu valgum.

PURPOSE

To evaluate the clinical and radiologic outcomes of surgical treatment with CWDFO for treatment of RPD with genu valgum.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Fourteen consecutive patients (23 knees) with RPD and genu valgum were treated with CWDFO. Patients with a minimum 2-year follow-up period were eligible for this study. Patients with prior failed surgery were also eligible. Radiographic evaluation was performed with mechanical femorotibial and lateral distal femoral angle. The radiographic parameters presenting patellar positions and pathologic abnormalities associated with RPD were evaluated. Chondral lesion changes in second-look arthroscopic examination were examined, and clinical outcomes (eg, occurrence of redislocation, range of motion, and clinical scores) were assessed pre- and postoperatively at a minimum of 2 years.

RESULTS

At a mean follow-up of 30.7 months (range, 25-62 months), the mean mechanical femorotibial and mechanical lateral distal femoral angles changed significantly from valgus 5° (range, 2°-11°) to varus 3° (2°-11°; P < .001) and from 83° (range, 78°-86°) to 89° (84°-92°; P < .001), respectively. The mean patellar congruence angle improved from 40° lateral (range, 20°-53° lateral) to 4° medial (23° medial to 21° lateral; P < .001), as did the lateral patellofemoral angle from 26° (range, 8°-62°) to 9° (0°-15°; P < .001). Computed tomography scans showed that the mean distance of patellar lateral shift decreased from 13.5 mm (range, 4-22 mm) to 2.0 mm (-4 to 5 mm; P < .001). The mean tibial tubercle to trochlear groove distance significantly decreased from 20.4 to 13.5 mm ( P < .001), while the Caton-Deschamps ratio did not change significantly after surgery ( P = .984). Chondral lesions of the patella and trochlear groove significantly improved or were maintained. None of the patients experienced subluxation or redislocation after surgery. Patellar instability symptoms also improved, as validated by radiographic and other clinical outcomes.

CONCLUSION

CWDFO combined with medial reefing and lateral release successfully treated RPD with genu valgum for a minimum follow-up of 2 years, with improved patellar alignment and stability.

Total knee arthroplasty after varus distal femoral osteotomy vs native knee: similar results in a case control study

PURPOSE

The aim of this study was to investigate the results of total knee arthroplasty (TKA) performed after varus distal femoral osteotomy (VrDFO), in comparison to a control group of TKAs performed as the primary intervention for arthrosis. Main hypothesis was that the medium term results for the two groups would be similar.

METHODS

All TKAs performed after VrDFO were extracted from a single centre, prospective database of 4046 arthroplasties. A case-control study was performed with a control group comprising two TKAs performed as the primary intervention for each TKA after VrDFO, and matched for sex, age at intervention, body mass index, the type of arthrosis and the type of implant. All prostheses used a system of posterior stabilisation by a third median condyle (Laboritoire Tornier-Wright). The primary outcome measure was the post-operative Knee Society Score (KSS).

RESULTS

Fourteen TKAs after VrDFO were identified, with a median follow-up of 42 months (12-102 months). The control group comprised 28 patients. There were no significant differences between groups in terms of the matching criteria. Pre-operatively, there were no differences between groups in terms of KSS (knee and function scores), range of motion (fixed-flexion and maximum flexion), and mechanical axes on long leg films. Operative duration was identical for the two groups. In the VrDFO group there was more lateral intra-operative laxity (p = 0.006), more intra-operative complications (patella tendon injuries, p = 0.0008), and more frequent need for screw support for the tibial component due to more severe lower limb deformity (p < 0.0001). No significant difference was found between groups with regards to the post-operative KSS; median knee score was 91.7 in the VrDFO group compared to 82.3 in the control group, and function score 70.6 compared to 77.8. Range of motion was comparable between groups with median maximum flexion in the VrDFO group of 115.7° and 110.9° in the control group.

CONCLUSION

TKAs after VrDFO is uncommon and can carry an increased risk of intra-operative complications. Despite this, the medium term results are comparable to arthroplasty performed as a primary intervention. TKA should not be denied to patients with previous femoral osteotomy, but care must be taken with gap balancing and axis correction.

LEVEL OF EVIDENCE

3.

A Combined Closing Wedge Distal Femoral Osteotomy and Medial Reefing Procedure for Recurrent Patellar Dislocation with Genu Valgum

PURPOSE

Recurrent patellar dislocation is often associated with genu valgum. The purpose of this study was to analyze the short-term results of single-incision, closing-wedge distal femoral osteotomy (CWDFO) combined with medial reefing and lateral release for recurrent patellar instability with genu valgum.

MATERIALS AND METHODS

Combined CWDFO/medial reefing/lateral release was performed on 10 knees. Clinical evaluation was based on pre- and postoperative Knee Society Score (KSS) and Kujala patellofemoral score. Radiographic evaluation was performed with reference to the weight-bearing line (WBL), the femorotibial angle (FTA), and the mechanical lateral distal femoral angles in the knee-standing view.

RESULTS

At a mean follow-up of 20±11.7 months (range, 12-42 months), KSS scores improved significantly, from 46.7±5.2 preoperatively to 87±4.4 postoperatively (p<0.001), as did the Kujala score, from 44±8 preoperatively to 86.6±6.8 postoperatively (p<0.001). The WBL decreased significantly, from 76±7% preoperatively to 41±11% postoperatively (p<0.001). The FTA was improved significantly, from 12.7±1.7° preoperatively to 4±4° postoperatively (p<0.001), as was the mLDFA, from 83±4° preoperatively to 91±1.3° postoperatively (p<0.001).

CONCLUSION

Use of single-incision CWDFO combined with medial reefing and lateral release prevents patellar dislocation, corrects deformity, and improves clinical outcomes.

Corrective osteotomy of the distal femur with fixator assistance: A novel technique of minimally invasive osteosynthesis

PURPOSE

Varus or valgus deformity of the distal femur may progress into knee osteoarthritis. To delay or prevent this, various types of corrective osteotomy techniques have been used to shift the mechanical axis from the diseased compartment to the healthy one. We introduced a new, minimally invasive osteotomy of the distal femur with the assistance of temporary external fixation.

METHODS

We retrospectively studied 25 legs that underwent open-wedge osteotomy of the distal femur, involving insertion of a Schanz pin at the medial femoral condyle and another pin at the distal diaphysis of the femur. At the meta-diaphyseal junction, osteotomy was performed. After achieving angular correction, two pins were locked for temporary external fixation and a locking plate was fixed at the lateral side of the femur submuscularly. Radiological and functional outcomes were evaluated, including mechanical lateral distal femoral angle (m-LDFA), mechanical axis deviation, tibiofemoral angle, osseous union, and knee joint motion.

RESULTS

The minimum follow-up was 12 months (mean, 39 months; range, 12-88 months). Bone healing occurred in all legs, with an average of 16.6 weeks. The m-LDFA was corrected from 77.7° (18 valgus) and 104.6° (7 varus) to 88.1° after surgery, with an average correction of 12.9°. At the final follow-up, the mechanical axis deviation averaged 7.6 mm and the tibia-femoral angle averaged 5.6°. Most of legs (88%) achieved acceptable m-LDFA (87° ± 3°).

CONCLUSIONS

A new, minimally invasive osteotomy of the distal femur offers excellent bone healing with few complications, attributable to preserved blood supply.

Geometry of the Valgus Knee: Contradicting the Dogma of a Femoral-Based Deformity

BACKGROUND

Realignment osteotomies of valgus knee deformities are usually performed at the distal femur, as valgus alignment is considered to be a femoral-based deformity. This dogma, however, has not been proven in a large patient population. Valgus malalignment may also be caused by a tibial deformity or a combined tibial and femoral deformity.

PURPOSE

The purposes of this study were (1) to analyze the coronal geometry of patients with valgus malalignment and identify the location of the underlying deformity and (2) to investigate the proportion of cases that require realignment osteotomy at the tibia, the femur, or both locations to avoid an oblique joint line.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

The analysis included 420 standing full-leg radiographs of patients with valgus malalignment (mechanical femorotibial angle [mFTA], ≥4°). A systematic analysis of the coronal leg geometry was performed including the mFTA, mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and joint-line convergence angle (JLCA). The localization of the deformity was determined according to the malalignment test described by Paley, and patients were assigned to 1 of 4 groups: femoral-based valgus deformity, tibial-based valgus deformity, femoral- and tibial-based valgus deformity, or intra-articular/ligamentary-based valgus deformity. Subsequently, the ideal osteotomy site was identified with the goal of a postoperative change of the joint line of two different maximum values, ±2° and ±4°, from its physiological varus position of 3°.

RESULTS

Measurements of the coronal alignment revealed a mean (±SD) mFTA of 7.4° ± 4.3° (range, 4°-28.2°). The mean mLDFA and mean mMPTA were 84.8° ± 2.4° and 90.9° ± 2.6°, respectively. The mean JLCA was 1.2° ± 3.1°. The majority (41.0%) of valgus deformities were tibial based, 23.6% were femoral based, 26.9% were femoral and tibial based, and 8.6% were intra-articular/ligamentary based. To achieve a straight-leg axis and an anatomic postoperative joint line with a tolerance of ±4°, the ideal site of a corrective osteotomy was tibial in 55.2% of cases and femoral in 19.5% of cases. A double-level osteotomy would be necessary in 25.2% of cases. With a tolerance of ±2°, the ideal osteotomy site was the proximal tibia in 41.0% of cases and the distal femur in 13.6% of cases; a double-level osteotomy would be necessary in 45.5% of cases.

CONCLUSION

In contrast to the widespread belief that valgus malalignment is usually caused by a femoral deformity, this study found that valgus malalignment was attributable to tibial deformity in the majority of patients. In addition, a combined femoral- and tibial-based deformity was more common than an isolated femoral-based deformity. As a clinical consequence, varus osteotomies to treat lateral compartment osteoarthritis must be performed at the tibial site or as a double-level osteotomy in a relevant number of patients to avoid an oblique joint line.

Distal femoral varus osteotomy for unloading valgus knee malalignment: a biomechanical analysis

PURPOSE

To investigate the biomechanical properties of the load shifting following opening-wedge distal femoral varus osteotomies (DFVOs) and determine the osteotomy correction needed to unload the lateral compartment.

METHODS

Five human cadaveric knees were tested with a load of 500 N of axial compression. Medial and lateral tibiofemoral compartment contact area and pressure were assessed utilizing a modified F-scan pressure-sensitive sensor. The knees were tested in their baseline anatomic alignment, 10° valgus malalignment and following corrective DFVOs of 5°, 10° and 15°. The load shifting effect of the various DFVO correction angles was analysed using a one-way ANOVA to determine the correction angle necessary to unload the lateral compartment.

RESULTS

Gradually shifting the loading vector medially with increasing DFVO angles resulted in a decrease in the mean contact area and mean contact pressures in the lateral compartment with progressive increases in the medial compartment. The largest reduction in lateral compartment pressure and contact area was seen with the 15° osteotomy with a 25 % decrease in mean contact pressure and 20 % decrease in mean maximum contact pressure and mean contact area when compared to the 10° valgus-malaligned knee. For the 10° valgus knee, a 15° correction resulted in near-normal contact pressures and areas compared with the knee in normal anatomic alignment.

CONCLUSION

Progressive unloading of the lateral tibiofemoral compartment occurred with increasing DFVO correction angles. Clinically, when performing a DFVO for valgus malalignment, surgeons should consider overcorrecting the osteotomy by 5° to restore near-normal contact pressures and contact areas in the lateral compartment rather than the traditional teaching of correcting to neutral alignment.

Role of computer-assisted surgery in osteotomies around the knee

PURPOSE

The goal of this article is to present our experience on navigation for osteotomies around the knee and especially osteotomies for coronal deformities. The first computer-assisted osteotomy was performed in March 2001 and since that time more than 1000 osteotomies have been performed in our department.

METHODS

All the osteotomies were performed with the Orthopilot^® device (B-Braun-Aesculap, Tuttlingen, Germany). The main indication was for genu varum deformities but several cases were operated for genu valgum. The surgical procedure as well as the indications and the rationale for each osteotomy (high tibial osteotomy-HTO, double-level osteotomy-DLO, femoral osteotomy-FO) are addressed in the article.

RESULTS

The results are focused on several papers published by the authors since more than 10 years. Regarding HTO for genu varum, the preoperative goal (HKA angle: 184° ± 2°) was reached in 96 % of cases and the difference was statistically significant compared to the non-navigated series (71 %: p < 0.05). Regarding DLO for genu varum, the preoperative goal was reached in 92.7 % for the HKA angle and in 88.1 % for the medial proximal tibial mechanical angle (MPTMA). Regarding genu valgum deformity, the preoperative goal was achieved in 86.2 % of cases for the HKA angle and 100 % of cases for the MPTMA.

CONCLUSION

According to these results, one can say that, regardless the type of osteotomy, the procedure is reliable, reproducible and accurate. Since 15 years, all the osteotomies around the knee are navigated in our department. Provided that one uses a reproducible radiograph protocol, navigation allows to perform double-level osteotomies, both for genu varum and genu valgum, with optimal accuracy in order to avoid oblique joint line, which will be difficult to revise to TKA.

LEVEL OF EVIDENCE

IV.

Good functional results of distal femoral opening-wedge osteotomy of knees with lateral osteoarthritis

PURPOSE

To evaluate the time-dependent functional outcome of patients with lateral knee osteoarthritis with increased valgus treated with lateral opening-wedge osteotomy to shift the load from the lateral to the medial compartment of the knee.

METHODS

Twenty-four consecutive patients with lateral knee osteoarthritis were treated with distal femoral opening-wedge varus osteotomy stabilized with the Puddu plate and bone transplantation. The mean age of the patients was 48 years (CI 40.3-55.7, range 31-62). The patients were evaluated by the Knee Injury and Osteoarthritis Outcome Score (KOOS) preoperatively and at 3 and 6 months, 1, 2, 5 and 10 years post-operatively. The knee osteoarthritis was graded according to the Kellgren-Lawrence radiological scoring system. The mean follow-up time was 7.9 years (CI 6.8-9.0, range 4.0-10.2).

RESULTS

The mean angular correction measured on pre- and post-operative radiographs was 9.6° (CI 7.7°-11.5°, range 4°-20°). All osteotomies healed. KOOS increased significantly during the first year by 28-122 % beyond the preoperative values for all the five subscores. This improvement remained at 10-year follow-up for those with surviving osteotomy. Six knees were converted to total knee arthroplasty (TKA) mean 6.4 years (CI 3.3-9.6, range 4.0-11.8) post-operatively. The osteotomy survival rate at 5 years was 88 % and at 10 years 74 %. The preoperative osteoarthritic grade did not increase significantly during the follow-up period, but was significantly correlated (r = -0.49), P = 0.019 to the KOOS subscore symptoms at the 2-year follow-up.

CONCLUSION

Distal femoral opening-wedge osteotomy for lateral knee osteoarthritis resulted in good functional recovery after 1 year and favourable midterm results. It may be a good treatment option for middle-aged patients with valgus knees and lateral osteoarthritis in order to prevent or postpone TKA.

LEVEL OF EVIDENCE

IV.

Better clinical results after closed- compared to open-wedge high tibial osteotomy in patients with medial knee osteoarthritis and varus leg alignment

PURPOSE

Studies comparing mid- or long-term outcomes of open- and closed-wedge high tibial osteotomy are limited. Here, the midterm survival rate and clinical and radiographic outcomes were compared for these two techniques. The study hypothesis, based on short-term follow-up, was that after midterm follow-up, the two techniques would not differ.

METHODS

A prospective follow-up study was conducted for a previously reported randomized controlled trial of an original 50 patients (25 open-wedge osteotomy and 25 closed-wedge osteotomy) with medial knee osteoarthritis and a varus leg alignment. We analyzed patients without knee arthroplasty (mean age 48.7 years, SD 8.0) for clinical and radiographic follow-up.

RESULTS

Five patients in each group had undergone conversion to a total knee arthroplasty or unicompartmental knee arthroplasty, leaving 19 patients for analysis in each group. At 7.9 years of follow-up (range 7-9 years), survival did not differ significantly between groups (open-wedge group 81.3% [95% confidence interval (CI) 75.2-100], closed-wedge group 82.0% [95% CI 66.7-100]). At final follow-up, total Dutch Western Ontario and McMaster Universities Arthritis (WOMAC), Knee Society Score, and visual analog scale (VAS) pain did not differ between groups. However, the results were significantly better in the closed-wedge group for VAS satisfaction and WOMAC pain and stiffness compared to the open-wedge group. Radiographic evaluation did not differ between groups for any outcome at final follow-up.

CONCLUSION

After a mean follow-up of 7.9 years, patients undergoing a closed-wedge osteotomy had favorable clinical results compared to those who underwent an open-wedge osteotomy.

LEVEL OF EVIDENCE

II.

Medial Closing-Wedge Distal Femoral Osteotomy: Fixation With Proximal Tibial Locking Plate

Distal femoral varus osteotomy is a well-established procedure for the treatment of lateral compartment cartilage lesions and degenerative disease, correcting limb alignment and decreasing the progression of the pathology. Surgical techniques can be performed with a lateral opening-wedge or medial closing-wedge correction of the deformity. Fixation methods for lateral opening-wedge osteotomies are widely available, and there are various types of implants that can be used for fixation. However, there are currently only a few options of implants for fixation of a medial closing-wedge osteotomy on the market. This report describes a medial, supracondylar, V-shaped, closing-wedge distal femoral osteotomy using a locked anterolateral proximal tibial locking plate that fits anatomically to the medial side of the distal femur. This is a great option as a stable implant for a medial closing-wedge distal femoral osteotomy.

Midterm results following medial closed wedge distal femoral osteotomy stabilized with a locking internal fixation device

PURPOSE

Aim of this study was to evaluate the subjective and radiological outcome and to evaluate the complications of a medial closing wedge osteotomy at the femur for lateral osteoarthritis with genu valgum.

METHODS

Twenty-three patients with grade III to IV cartilage damage and valgus knee alignment were treated with medial closing wedge osteotomy at the distal femur. The osteotomy was stabilized with an internal plate fixator. Age varied between 25 and 55 years (mean 47 years). One patient was lost to final follow-up.

RESULTS

After 3.5 years, all Knee Osteoarthritis Outcome Score (KOOS) subitems increased significantly. There was no significant difference in the subgroup analysis of KOOS subitems for patients with and without microfracture or age (>50 vs. <50 years). There were no perioperative complications. One patient had an overcorrection. All, but one osteotomy, showed stable bone healing. There was a loss of correction due to delayed bone healing in one case. Possible explanations for this complication were injury of the lateral cortex or smoking. This case required revision with bone graft and an additional lateral plate. In no case, a conversion to an endoprosthesis was necessary.

CONCLUSION

The femoral medial closing wedge osteotomy is a surgical method for improving symptoms of lateral osteoarthritis in the valgus knee.

LEVEL OF EVIDENCE

IV.

Computer-assisted osteotomy for valgus knees: medium-term results of 29 cases

INTRODUCTION

Computer-assisted surgery has been shown to be beneficial for correcting misaligned lower limbs. The purpose of this study was to analyze the medium-term results of computer-assisted osteotomy for 29 valgus knees. The hypothesis was that computer navigation would allow a valgus deformity to be corrected with similar precision as varus deformity.

MATERIAL AND METHODS

The series consisted of 27 patients (29 knees); there were 7 men and 20 women with ages ranging from 15 to 63 years (mean: 42.4±14.3 years). Twenty-four varus osteotomies of the femur (14 medial closing and 10 lateral opening) and five double osteotomies (proximal tibia and distal femur) were performed. The pre-operative functional status was evaluated with the Lysholm-Tegner score. The mean score was 64±20.5 points (range: 18-100). According to Ahlbäck's modified classification for knee osteoarthritis, 12 patients were at stage 1, nine were at stage 2, five at stage 3 and one at stage 4. Two of the knees had no radiological signs of osteoarthritis but had a particularly unsightly deformity; one of these was secondary to high tibial valgus osteotomy. The mean pre-operative hip-knee-angle (HKA) angle was 189.3±3.9°; the mean mechanical medial distal femoral angle (mMDFA) was 97.2±2.6° and mechanical medial proximal tibial angle (mMPTA) was 90.1±2.8°. The goal was to achieve an HKA angle of 179±2° and mMPTA of 90±2° to avoid an oblique joint line. Functional outcomes were evaluated with the Lysholm-Tegner, KOOS and IKS scores.

RESULTS

No complications other than a transient paralysis of the common fibular nerve were observed. Twenty-three patients (25 knees) were reviewed at a mean follow-up of 50.9±38.8 months (range: 6-144). The mean Lysholm-Tegner score was 92.9±4 points (86-100), the mean KOOS was 89.7±9.3 (range: 68-100), the mean IKS "knee" score was 88.7±11.4 points (range: 60-100) and the "function" score was 90.6±13.3 points (range: 55-100). Twenty-two patients were satisfied or very satisfied. The mean HKA angle was 180.1±1.9°, the mean mMDFA 90.7±2.5° and the mean mMPTA 89.1±1.9°. The pre-operative goal was achieved in 86.2% of cases (25/29) for the HKA angle and 100% of cases of the mMPTA angle. At the follow-up, none of the knees had been revised with a prosthesis.

CONCLUSION

Computer-assisted osteotomy for cases of osteoarthritis secondary to valgus knee leads to excellent medium-term results. Navigation provides reliable and accurate deformity correction.

LEVEL OF EVIDENCE

IV. Retrospective study.