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

Biomechanical Comparison of Uniplanar versus Biplanar Lateral Opening-wedge Distal Femoral Osteotomy Techniques in Terms of Risk for Medial Hinge Fracture

The effect of osteotomy type on the initial stiffness of the bone-implant construct in lateral opening-wedge distal femoral osteotomy (LOWDFO) using a uniplanar compared with a biplanar technique has been investigated. However, no study has explored the biomechanical risk factors for medial hinge fracture. This study aimed to compare the biomechanical strength of uniplanar versus biplanar LOWDFO regarding the risk for medial hinge fracture during gap opening. Twelve composite femora were divided into two groups (six in each group) based on the distal femoral osteotomy technique: uniplanar versus biplanar LOWDFO. All LOWDFO models were subjected to incremental static loading. The gap distance was expanded by 1 mm, and displacement values were recorded as anterior and posterior gap distances (mm). The average force values of all samples at certain gap distances were recorded, and the head distance was measured. The uniplanar group had higher load values than the biplanar group at all anterior gap distances. These differences were only significant at 2- and 3-mm gap distances (p = 0.025 and 0.037). At all posterior gap distances, the uniplanar group had higher load values than the biplanar group, but these differences only reached statistical significance at 2 mm (p = 0.037). Both groups had similar anterior, posterior, and average gap distances (p = 0.75, 0.522, 0.873). The uniplanar group had a higher head insertion distance (15.3 ± 5.7) than the biplanar group (14.7 ± 2.9), but it was not significant (p = 0.87). The uniplanar group had a lower average load before medial hinge fracture (46.41 ± 13.91 N) than the biplanar group (54.92 ± 31.94, p = 0.81). The biplanar group had an average maximum load value of 64.18 ± 25.6 N, while the uniplanar group had 57.90 ± 12.21 N (p = 0.81). This study revealed that the biplanar osteotomy technique allows a wider opening wedge gap with less risk of a medial hinge fracture than uniplanar LOWDFO.Level of evidence was level 3, case-control series.

Additional Plate Fixation of Hinge Fractures After Varisation Distal Femoral Osteotomies Provides Favorable Torsional Stability: A Biomechanical Study

BACKGROUND

Hinge fractures are considered risk factors for delayed or nonunion of the osteotomy gap in distal femoral osteotomies (DFOs). Limited evidence exists regarding the treatment of hinge fractures after DFO, which could improve stability and thus bone healing.

PURPOSE

To (1) examine the effect of hinge fractures on the biomechanical properties of the bone-implant construct, (2) evaluate the biomechanical advantages of an additional fixation of a hinge fracture, and (3) test the biomechanical properties of different types of varisation DFOs.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 32 fresh-frozen human distal femora equally underwent medial closing wedge DFO or lateral opening wedge DFO using a unilateral locking compression plate. The following conditions were serially tested: (1) preserved hinge; (2) hinge fracture along the osteotomy plane; (3) screw fixation of the hinge fracture; and (4) locking T-plate fixation of the hinge fracture. Using a servo-hydraulic materials testing machine, we subjected each construct to 15 cycles of axial compression (400 N; 20 N/s) and internal and external rotational loads (10 N·m; 0.5 N·m/s) to evaluate the stiffness. The axial and torsional hinge displacement was recorded using a 3-dimensional optical measuring system. Repeated-measures 1-way analysis of variance and post hoc Bonferroni correction were used for multiple comparisons. Statistical significance was set at P < .05.

RESULTS

Independent from the type of osteotomy, a fractured hinge significantly (P < .001) increased rotational displacement and reduced stiffness of the bone-implant construct, resulting in ≥1.92 mm increased displacement and ≥70% reduced stiffness in each rotational direction, while the axial stiffness remained unchanged. For both procedures, neither a screw nor a plate could restore intact rotational stiffness (P < .01), while only the plate was able to restore intact rotational displacement. However, the plate always performed better compared with the screw, with significantly higher and lower values for stiffness (+38% to +53%; P < .05) and displacement (-55% to -72%; P < .01), respectively, in ≥1 rotational direction. At the same time, the type of osteotomy did not significantly affect axial and torsional stability.

CONCLUSION

Hinge fractures after medial closing wedge DFO and lateral opening wedge DFO caused decreased bone-implant construct rotational stiffness and increased fracture-site displacement. In contrast, the axial stiffness remained unchanged in the cadaveric model.

CLINICAL RELEVANCE

When considering an osteosynthesis of a hinge fracture in a DFO, an additional plate fixation was the construct with the highest stiffness and least displacement, which could restore intact hinge rotational displacement.

Short- to mid-term results of minimally invasive lateral unicompartmental knee replacement: 133 cases in a non-designer series

INTRODUCTION

The aim of the current study was to demonstrate short- to mid-term survivorship as well as clinical outcome of lateral unicompartmental knee replacement (UKR) with a fixed-bearing (FB) design from a non-designer center using the Oxford Fixed Lateral prosthesis.

MATERIALS AND METHODS

This single-center retrospective cohort study reports the results of 133 consecutive lateral FB-UKR. Survivorship analysis was performed with different endpoints and clinical outcome was measured using the Oxford-Knee-Score (OKS), American-Knee-Society-Score (AKSS-O), range-of-motion (ROM) and visual-analog-scale for pain (VAS).

RESULTS

There were two revision surgeries with conversion to total knee replacements (TKR) due to persistent pain resulting in a survival rate of 98.5% (95% CI 93.5-99.6) with a mean follow-up (FU) of 3.3 ± 1.8 years (range 1-8.5). All outcome scores, VAS and ROM showed a significant improvement at final FU (p < 0.001). The OKS improved from 26 ± 7.8 (range 11-45) preoperatively to 39 ± 8.3 (range 13-48), the AKSS-O from 49.2 ± 14.6 (range 18-90) to 81.8 ± 15.1 (range 40-100), the AKSS-F from 53 ± 23.7 (range 0-100) to 80.4 ± 21.4 (range 5-100) and the ROM from 118 ± 17 (range 90-160) to 134 ± 9.5 (range 100-155).

CONCLUSIONS

The short- to mid-term results following lateral FB-UKR demonstrate a high survivorship and good clinical outcome from an independent series. We, therefore, suggest that FB-UKR is a safe treatment option for isolated lateral OA if sufficient surgical experience is provided.

LEVEL OF EVIDENCE

Retrospective cohort study, level IV.

Lateral meniscus autograft transplantation using hamstring tendon with a sandwiched bone marrow - derived fibrin clot: A case report

INTRODUCTION AND IMPORTANCE

Tendon autograft is a durable solution for the sub/total meniscus; however it is still considered a temporary solution.

CASE PRESENTATION

We report the case of a 17-year-old woman with history of subtotal lateral meniscectomy performed 6 years ago. We treated her with lateral meniscus autograft transplantation using a hamstring tendon with a sandwiched bone marrow aspirate (BMA)-derived fibrin clot. T2 relaxation times of the anterior and posterior horns of both menisci and of the cartilage were assessed.

CLINICAL DISCUSSION

Lateral meniscus autograft transplantation using a hamstring tendon with a sandwiched BMA clot improved clinical and radiographic outcomes at the 24-month follow-up. These findings suggest that the lateral meniscus autograft transplantation using a hamstring tendon with a sandwiched BMA clot transformed into a meniscus-like tissue and resulted in preservation of the articular cartilage.

CONCLUSION

Lateral meniscus autograft transplantation using a hamstring tendon with a sandwiched BMA clot can function as a meniscal transplant after total or subtotal meniscectomy in young patients.

Effects of Lateral Opening-Wedge Distal Femoral Osteotomy on Meniscal Allograft Transplantation: A Biomechanical Evaluation

Background

Lateral meniscal deficiency with valgus malalignment increases the rate of lateral compartment osteoarthritis. Lateral meniscal allograft transplantation (LMAT) with a concomitant varus-producing opening-wedge distal femoral osteotomy (DFO) is an option yet to be evaluated biomechanically.

Purpose/Hypothesis

The purpose of this study was to clarify the biomechanical effects of the realignment procedure in the setting of LMAT. We hypothesized that (1) given the dependence of the lateral compartment on the lateral meniscus, a DFO and increasing degrees of varus would be insufficient to restore lateral compartment pressures to normal from a lateral meniscus-deficient state, and that (2) LMAT would restore lateral compartment pressures to the intact state while DFO would decrease lateral compartment pressures for any given state of the meniscus.

Study Design

Controlled laboratory study.

Methods

Ten cadaveric knees underwent opening-wedge varus-producing DFO secured by an external fixator. Anatomic alignment was standardized to 6° of mechanical valgus, and each joint was tested in full extension. Submeniscal placement of thin film pressure sensors allowed for the recording of contact pressure, peak contact pressure, and contact area. The specimens were loaded on a biaxial dynamic testing machine with loading angles between 9° valgus and 6° varus of mechanical alignment. Conditions tested included intact meniscus, meniscal deficiency, and meniscal transplantation.

Results

Isolated varus-producing DFO to 6° in the meniscus-deficient state failed to restore joint pressures and contact areas to the intact state, with significant changes in mean contact pressure (175%), mean peak contact pressure (135%), and contact area (-41%) (all P < .05 vs intact), while LMAT restored all outcome measures (all P > .05 compared with intact). After LMAT, every additional 1° of DFO correction contributed to a decrease in the mean contact pressure, peak pressure, and contact area of 5.6% (-0.0479 N/mm²), 5.9% (-0.154 N/mm²), and 1.4% (-6.99 mm²) for the lateral compartment and 7.3% (+0.034 N/mm²), 12.6% (+0.160 N/mm²), and 4.3% (+20.53 mm²) for the medial compartment, respectively.

Conclusion

Isolated DFO was inadequate to restore load distribution in meniscus-deficient knees, while concomitant LMAT restored near normal forces and improved the lateral compartment biomechanical profile.

Clinical Relevance

Our findings support the concomitant use of LMAT and varus-producing DFO in the setting of lateral meniscal deficiency with valgus malalignment. This study provides tools for the orthopaedic surgeon to individualize the correction for each patient.

Finite element analysis of medial closing and lateral opening wedge osteotomies of the distal femur in relation to hinge fractures

PURPOSE

Intraoperative hinge fractures in distal femur osteotomies represent a risk factor for loss of alignment and non-union. Using finite element analysis, the goal of this study was to investigate the influence of different hinge widths and osteotomy corrections on hinge fractures in medial closed-wedge and lateral open-wedge distal femur osteotomies.

METHODS

The hinge was located at the proximal margin of adductor tubercle for biplanar lateral open-wedge and at the upper border of the lateral femoral condyle for biplanar medial closed-wedge distal femur osteotomies, corresponding to optimal hinge positions described in literature. Different hinge widths (5, 7.5, 10 mm) were created and the osteotomy correction was opened/closed by 5, 7.5 and 10 mm. Tensile and compressive strain of the hinge was determined in a finite element analysis and compared to the ultimate strain of cortical bone to assess the hinge fracture risk.

RESULTS

Doubling the correction from 5 to 10 mm increased mean tensile and compressive strain by 50% for lateral open-wedge and 48% for medial closed-wedge osteotomies. A hinge width of 10 mm versus 5 mm showed increased strain in the hinge region of 61% for lateral open-wedge and 32% for medial closed-wedge osteotomies. Medial closed-wedge recorded a higher fracture risk compared to lateral open-wedge osteotomies due to a larger hinge cross-section area (60-67%) for all tested configurations. In case of a 5 mm hinge, medial closed-wedge recorded 71% higher strain in the hinge region compared to lateral open-wedge osteotomies.

CONCLUSION

Due to morphological features of the medial femoral condyle, finite element analysis suggests that lateral-open wedge osteotomies are the preferable option if larger corrections are intended, as a thicker hinge can remain without an increased hinge fracture risk.

Outcomes of Distal Femoral Osteotomy for Valgus Malalignment: A Systematic Review and Meta-analysis of Closing Wedge Versus Opening Wedge Techniques

BACKGROUND

Valgus knee deformity increases the risk for lateral articular chondral damage, contributing to earlier onset and accelerated progression of osteoarthritis. Distal femoral osteotomy (DFO) unloads the lateral joint compartment and can be performed using closing wedge (CW) or opening wedge (OW) techniques.

PURPOSE

To perform a systematic review and meta-analysis for patients with valgus knee deformity undergoing DFO to determine differences in patient-reported outcome measures (PROMs), complications, and survival rates, comparing CW versus OW DFO.

STUDY DESIGN

Systematic review, Level of evidence, 4.

METHODS

A literature review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines utilizing PubMed, Cochrane Database, Ovid/MEDLINE, and Scopus. Inclusion criteria consisted of studies reporting outcomes in patients undergoing CW or OW DFO for the treatment of valgus knee deformities with symptomatic lateral compartment pathology with a minimum 2-year follow-up. PROMs and complications were analyzed using random-effects modeling to identify differences in outcomes as a function of surgical technique. Long-term survival data, defined as conversion to total knee arthroplasty, were analyzed using a multiple metaregression model as a function of individual study follow-up time points and surgical technique.

RESULTS

In total, we included 23 retrospective studies (n = 619 knees), of which 10 studies (n = 271 knees) reported outcomes after CW DFO and 13 studies (n = 348 knees) reported on OW DFO outcomes. Good to excellent clinical outcomes were reported in PROMs when compared with preoperative values with both techniques, while no significant differences between techniques were appreciated on functional Knee Society Scores and Tegner scores. No significant differences were appreciated in the incidence of complications reported in patients undergoing CW (20%) versus OW (33%) DFO (P = .432). Pain requiring hardware removal was the most commonly reported complication in both groups. The survival rate for CW DFO was 81.5% (mean follow-up, 8.8 ± 4.3 years) compared with 90.5% for OW DFO (mean follow-up, 4.5 ± 1.5 years). Multiple metaregression demonstrated that patient follow-up (P < .001) was significantly associated with knee survival, while surgical technique (P = .810) was not a predictor of clinical failure.

CONCLUSIONS

Both CW and OW DFO techniques were associated with good to excellent clinical outcomes with no significant differences in PROMs based on technique. Pain requiring hardware removal was the most common complication in both techniques, while long-term survivability was found to be a function of follow-up and not surgical technique. Technique selection should be based on shared patient-physician decision making with an emphasis on surgeon preference and technique familiarity.

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.

Correction of Severe Knees Valgus Deformities in a Patient With Renal Osteodystrophy

Renal osteodystrophy (ROD) is a complex and rare entity that refers to a large spectrum of abnormalities of skeletal homeostasis in patients suffering from chronic kidney disease. The goal of this study was to present the outcome of the very rare case of an adult with severe deformity of painful bilateral valgus knees due to ROD, requiring multilevel osteotomies above and below the knee. A 42-year-old male patient was admitted to our department with painful severe bilateral valgus knees deformity due to ROD. The patient underwent bilateral lateral opening-wedge osteotomy of distal femur and medial tibial closing-wedge osteotomy. The osteotomies site healed in 8 weeks without complications. The surgical treatment of lower limb valgus knee deformities secondary to ROD is a challenging and demanding procedure. In our patient, the femoral opening-wedge osteotomy with blade-plate fixation, and tibial closing-wedge osteotomy with plate fixation, restored almost normal knee congruency to prevent lateral unicompartmental degenerative deterioration of the knee.

Distal femoral osteotomy versus lateral unicompartmental arthroplasty for isolated lateral tibiofemoral osteoarthritis with intra-articular and extra-articular deformity: a propensity score-matched analysis

Purpose

Lateral unicompartmental arthroplasty (UKA) and distal femoral osteotomy (DFO) represent surgical solutions in cases of valgus malalignment and isolated lateral osteoarthritis (OA) of the knee. The aim of the present study was to assess the clinical results, complications, and the overall postoperative alignment of a series of DFO and lateral UKA with a minimum 2-year follow-up in active middle-aged patients.

Methods

Patients with valgus knee and isolated lateral OA who underwent opening-wedge DFO or UKA from 2017 to 2019 were reviewed. Each patient was characterized by a joint line convergence angle (JLCA) > 3° and mechanical lateral distal femoral angle (mLDFA) < 87°. We excluded patients who underwent meniscus or osteochondral allograft during DFO. The Oxford Knee Score (OKS), Knee Injury and Osteoarthritis Outcome Score (KOOS), complications, and postoperative alignment were assessed. Propensity score matching was used to identify comparable patients.

Results

The DFO and lateral UKA groups consisted of 29 patients each. No statistically significant differences in gender, age, body mass index (BMI), length of follow-up, or limb deformity were reported between the two groups. In the DFO group, OKS was reported to improve from 27.51 to 38.59 (p < 0.05) and KOOS from 51.14 to 67.2 (p < 0.05). Similarly, in the UKA group, OKS improved from 26.23 to 35.43 (p < 0.05) and KOOS from 50.12 to 65.91 (p < 0.05). However, the improvement in OKS and KOOS (delta) did not differ between groups (p = 0.35 and p = 0.95). The DFO and UKA groups were characterized by similar postoperative hip-knee-ankle (HKA) angle measurements of −3.26 and −3.00, respectively (p = 0.65). No patients in the UKA group underwent revision or other knee surgeries during follow-up. No infections were detected in either group. In the DFO group, no cases of nonunion or delayed union were reported. However, 40% of DFO patients underwent plate removal. One patient in each group was characterized by progression of medial OA with Kellgren-Lawrence (KL) grade > 3.

Conclusion

UKA and DFO represent an effective treatment in lateral knee OA with intra-articular and extra-articular deformity. Both surgeries were able to provide a significant and comparable clinical improvement.

Level of evidence: III, comparative retrospective cohort study.

Dislocated hinge fractures are associated with malunion after lateral closing wedge distal femoral osteotomy

PURPOSE

To evaluate the incidence, morphology, and associated complications of medial cortical hinge fractures after lateral closing wedge distal femoral osteotomy (LCW-DFO) for varus malalignment and to identify constitutional and technical factors predisposing for hinge fracture and consecutive complications.

METHODS

Seventy-nine consecutive patients with a mean age of 47 ± 12 years who underwent LCW-DFO for symptomatic varus malalignment at the authors' institution between 01/2007 and 03/2018 with a minimum of 2-year postoperative time interval were enrolled in this retrospective observational study. Demographic and surgical data were collected. Measurements evaluating the osteotomy cut (length, wedge height, hinge angle) and the location of the hinge (craniocaudal and mediolateral orientation, relation to the adductor tubercle) were conducted on postoperative anterior-posterior knee radiographs and the incidence and morphology of medial cortical hinge fractures was assessed. A risk factor analysis of constitutional and technical factors predisposing for the incidence of a medial cortical hinge fracture and consecutive complications was conducted.

RESULTS

The incidence of medial cortical hinge fractures was 48%. The most frequent morphological type was an extension fracture type (68%), followed by a proximal (21%) and distal fracture type (11%). An increased length of the osteotomy in mm (53.1 ± 10.9 vs. 57.7 ± 9.6; p = 0.049), an increased height of the excised wedge in mm (6.5 ± 1.9 vs. 7.9 ± 3; p = 0.040) as well as a hinge location in the medial sector of an established sector grid (p = 0.049) were shown to significantly predispose for the incidence of a medial cortical hinge fracture. The incidence of malunion after hinge fracture (14%) was significantly increased after mediolateral dislocation of the medial cortical bone > 2 mm (p < 0.05).

CONCLUSION

Medial cortical hinge fractures after LCW-DFO are a common finding. An increased risk of sustaining a hinge fracture has to be expected with increasing osteotomy wedge height and a hinge position close to the medial cortex. Furthermore, dislocation of a medial hinge fracture > 2 mm was associated with malunion and should, therefore, be avoided.

LEVEL OF EVIDENCE

Prognostic study; Level IV.

Osteotomies for lateral compartment knee osteoarthritis

Lateral compartment osteoarthritis (LCOA) is often associated with valgus deformity of the knee. The concept of correcting the alignment by performing distal femoral varus osteotomy (DFVO) to unload the lateral compartment is well accepted and it is viewed as the preferred option for young active patients due to dissatisfaction from arthroplasty under 55 years of age or if they wish to remain active. Beyond this there is no consensus on patient selection, preoperative assessment, techniques to achieve correction, end point of correction, return to work or sports post-surgery, and survivorship of osteotomy with conversion to a total knee replacement as the end point due to heterogenous, retrospective studies. Here, we review relevant literature to help patient selection, preoperative work up, techniques, and outcomes.

High Tibial Osteotomy: An Update for Radiologists

High tibial osteotomy (HTO) is a surgical procedure to treat symptomatic unicompartmental osteoarthritis (OA) associated with knee malalignment. There has been a recent resurgence of interest in HTO in patients who prefer joint-preserving surgery, as HTO shifts the knee's mechanical axis from the arthritic compartment to a neutral position, thereby reducing knee pain, slowing progression of OA, and delaying the need for a total knee arthroplasty. The ideal candidates for HTO are young, active, nonobese patients with isolated varus deformity of the knee due to medial compartment OA. Radiography is critical in the preoperative evaluation for HTO and can help expand surgical indications to include a wider variety of patients. Radiography is also routinely obtained in postoperative assessment and is typically the first test to suspect complications. This review describes the radiologic aspects of HTO, including preoperative imaging assessment, as well as normal and abnormal postoperative imaging appearances. Surgical techniques and osteotomy fixation devices are described, with a focus on the medial opening wedge approach. Given the growing interest in HTO, radiologists should become familiar with the basics of the procedure and the role of imaging in preoperative and postoperative evaluation.

Detection of Lateral Hinge Fractures After Medial Closing Wedge Distal Femoral Osteotomy: Computed Tomography Versus Plain Radiography

BACKGROUND

Limited evidence exists in the literature regarding the detection rates of lateral hinge fracture (LHF) on computed tomography (CT) after medial closing wedge distal femoral osteotomy (MCDFO). Moreover, the effect of LHF on bone healing after MCDFO remains unclear.

HYPOTHESIS

The detection rates of LHF after MCDFO would be higher on CT than on plain radiography. The incidence of problematic bone healing would be higher in the knees with LHF than in those without LHF.

STUDY DESIGN

Cohort study (diagnosis), Level of evidence, 3.

METHODS

Patients who underwent MCDFO between May 2009 and July 2019 were retrospectively evaluated. The presence of LHF was evaluated using immediate postoperative plain radiography and CT. The detection rates of LHF on plain radiography and CT were compared. The incidence of problematic bone healing (nonunion, delayed union, and loss of correction) was also compared between the knees with LHF and those without LHF.

RESULTS

A total of 55 knees of 43 patients (mean age, 37.7 ± 16.7 years) were included in the study. Although 33 LHFs were detected on CT, only 19 LHFs were detected on plain radiography. The detection rate of LHF was significantly higher on CT than on plain radiography (60% vs 34.5%; P = .008). At 1-year follow-up, 10 cases of problematic bone healing (1 nonunion, 4 delayed unions, and 5 losses of correction) were identified. The incidence of problematic bone healing was significantly higher in the knees with LHF than in those without LHF as shown on plain radiography (36.8% vs 8.3%; P = .001) and CT (30.3% vs 0%; P = .004).

CONCLUSION

LHF can be detected better on CT than on plain radiography and has a negative effect on bone healing after MCDFO. For patients with LHF detected on either plain radiography or CT, careful rehabilitation with close follow-up is recommended.

Osteotomy Around the Knee: The Surgical Treatment of Osteoarthritis

Osteoarthritis causes joint pain and functional disorder, of which knee osteoarthritis is the most common. Nowadays, clinically effective treatments mainly include conservative treatment, arthroplasty, and osteotomy. However, conservative treatment only offers symptomatic relief and arthroplasty is limited to the patients with a moderate to severe degree of osteoarthritis. For relatively young patients who require greater knee preservation, a surgical treatment with low operation trauma and revision rate is needed. Osteotomy around the knee, based on the notion of “knee preservation,” has been chosen as an alternative surgical treatment. Cutting and realigning the bones corrects the mechanical line of lower limb force bearing. As such, osteotomy around the knee retains normal anatomical structure and obtains good functional recovery of the knee joint. The techniques of osteotomy around the knee includes anti‐varus deformity and anti‐valgus deformity osteotomy, aiming to reallocate the force bearing in the compartment of the knee joint. By choosing the surgical section of the lower limbs, the osteotomy around the knee can achieve the correction of mechanical axis, such as the high tibial osteotomy (HTO), proximal fibular osteotomy (PFO), and distal femur osteotomy (DFO). Numerous modified techniques have been developed to meet the demands of patients based on traditional methods. These modified osteotomy have their own advantages and indications. This paper aims to guide clinical treatment by reviewing different types of osteotomies, and their effects, that have been studied and applied widely in clinical practices.

Ten-year survival rate of 89% after distal femoral osteotomy surgery for lateral compartment osteoarthritis of the knee

PURPOSE

The purpose of this study was to assess the accuracy, safety, and survival of distal femoral osteotomy (DFO) surgery for lateral compartment OA of the knee.

METHODS

A retrospective cohort study was conducted at a single UK centre, using prospectively collected data over an 8-year period (2009-2017). All patients had pre-operative radiographic analysis and digital planning of their deformity correction in addition to post-operative analysis of the achieved correction and yearly face-to-face follow-up. Complications (defined as an undesirable medical or surgical event as a direct result of the operation), reoperations, and failure (defined as conversion to arthroplasty or revision) were recorded.

RESULTS

From a total of 83 patients, 81 patients undergoing 86 primary DFOs were included in this study, with a mean follow-up of 99 months (SD 27 months). The mean pre-operative percentage Mikulicz point was 78.7% (SD 19.1%) and post-operative 35.9% (SD 14.8%). The mean accuracy of correction (intended correction - achieved correction) was an 8.2% overcorrection (SD 13.7%). The complication rate was 4.7%. Using Kaplan-Meier analysis, the mean survival was 113 months (95% CI 106-120) with the probability of surviving 10 years 89%.

CONCLUSION

DFO for valgus alignment and lateral compartment arthritis is associated with low complications, long-term joint preservation, and the prevention of arthroplasty surgery. However, the accuracy of correction still requires improvement in intra-operative technique.

LEVEL OF EVIDENCE

IV.

A hinge position distal to the adductor tubercle minimizes the risk of hinge fractures in lateral open wedge distal femoral osteotomy

PURPOSE

To evaluate the incidence and morphology of medial cortical hinge fractures in lateral open wedge distal femoral osteotomy (LOW-DFO) and to determine a safe zone for the position of the osteotomy hinge to minimize the risk of hinge fractures.

METHODS

Consecutive patients who underwent LOW-DFO for symptomatic valgus malalignment were screened for eligibility for this retrospective observational cohort study. Demographical and surgical data were collected. The incidence and morphology of medial cortical hinge fractures were evaluated on standard postoperative anterior-posterior knee radiographs. Comprehensive measurements evaluating the osteotomy gap and the position of the osteotomy hinge were taken. Additionally, each osteotomy hinge was assigned to a corresponding sector of a proposed five-sector grid of the distal medial femur.

RESULTS

A total of 100 patients (60% female) with a mean age of 31 ± 13 years were included. The overall incidence of medial cortical hinge fractures was 46% and three distinct fracture types were identified. The most frequently observed fracture type was extension of the osteotomy gap (76%), followed by a proximal (20%) and distal (4%) course of the fracture line in relation to the hinge. Group comparison (hinge fracture vs. no hinge fracture) showed statistically significant higher values for the height of the osteotomy gap (p = 0.001), the wedge angle (p = 0.036), and the vertical distance between the hinge and the proximal margin of the adductor tubercle (AT; p = 0.002) in the hinge fracture group. Furthermore, a significantly lower horizontal distance between the hinge and the medial cortical bone (p = 0.036) was observed in the hinge fracture group. A statistically significant higher incidence of medial cortical hinge fractures was observed when the position of the osteotomy hinge was proximal compared to distal to the proximal margin of the AT (53% vs. 27%; p = 0.023).

CONCLUSION

Medial cortical hinge fractures in LOW-DFO are a common finding with three distinct fracture types. To minimize the risk of medial cortical hinge fractures, it is recommended to aim for a position of the osteotomy hinge at the level of or distal to the proximal margin of the adductor tubercle.

LEVEL OF EVIDENCE

Prognostic study; Level III.

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.

Two-Year Outcomes After Meniscoplasty by Capsular Advancement With the Application of Arthroscopic Centralization Technique for Lateral Compartment Knee Osteoarthritis

BACKGROUND

A high prevalence of osteoarthritis (OA) progression in patients with lateral meniscal defects has been reported. However, optimal management techniques for active patients remain ill-defined.

HYPOTHESIS

Meniscoplasty by capsular advancement with the application of the centralization technique would improve clinical and radiological outcomes in patients with lateral compartment OA attributed to lateral meniscal defects.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 27 patients were enrolled who had undergone meniscoplasty by capsular advancement for lateral compartment OA attributed to lateral meniscal defects. In these patients, the meniscotibial capsule was released from the tibia and advanced with the remaining meniscus onto the rim of the tibial plateau to reform a meniscus-like configuration. Measures of clinical outcomes included clinical examination, Lysholm score, International Knee Documentation Committee (IKDC) subjective score, Knee injury and Osteoarthritis Outcome Score (KOOS), subjective rating scales regarding recovery of the operated knee, and sports performance level. Measures of radiographic outcomes included meniscal extrusion width or regeneration of the meniscus-like tissue on magnetic resonance imaging and lateral joint space width on standing extension anteroposterior and Rosenberg views. All clinical and radiographic outcomes were reported preoperatively and 2 years postoperatively, except magnetic resonance imaging findings, which were reported preoperatively and 1 year postoperatively.

RESULTS

The clinical outcomes were significantly improved 2 years postoperatively as compared with baseline: Lysholm score, IKDC subjective score, and KOOS subscores (all P < .0001). The patients' subjective recovery (P < .0001) and sports performance level (P < .0001) were also improved. One year postoperatively, 10 of 11 patients who had no meniscus remaining at the middle segment showed more than one-third the volume of meniscal tissue-like regeneration, and meniscal extrusion width was significantly reduced as compared with baseline in the remaining 16 patients (P = .0006). Joint space width increased at 2 years on the standing anteroposterior view (P < .0001) and the Rosenberg view (P = .0001).

CONCLUSION

Meniscoplasty of the lateral meniscus by capsular advancement improved clinical and radiographic outcomes at 2-year follow-up in patients with lateral compartment OA attributed to lateral meniscal defects.

Resultados a longo prazo de osteotomia varizante femoral distal (OVFD) com cunha de abertura lateral para artrose do compartimento lateral do joelho utilizando navegação computadorizada

Objective  The primary aim of the present study was to evaluate the long-term outcomes including survivorship of computer navigated distal femoral lateral opening wedge osteotomy (DFLOWO). The secondary aim was to identify the potential factors that may influence its survivorship.

Methods  A retrospective analysis of prospectively collected data for patients with lateral compartment arthritis who underwent navigated DFLOWO from December 2006 to November 2012 was performed. The International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) scores were analyzed for outcome measures. Conversion to arthroplasty during the follow-up was the end point.

Results  A total of 19 DFLOWOs were performed in 17 patients with a mean age of 46.6 ± 6.5 years formed the study cohort. The coronal alignment was corrected from a mean of 7.1° (2–11°) valgus to a mean of 2.1° (0.5°–3°) varus. The IKDC scores improved from mean of 39 preoperatively to 53 at the mean long-term follow-up of 9.1 years. The mean KOOS scores at the long-term follow-up were pain 71, symptoms 56, activities of daily living 82, sports and recreation 59, quality of life 43. Survivorship of the DFLOWO was 78.9% at a follow-up of 9.1 years. Presence of ≥ grade 2 according to the International Cartilage Repair Society (ICRS) cartilage degeneration in the medial compartment of the knee and >7° preoperative valgus deformity were strongly correlated with conversion to total knee arthroplasty (TKA) at the long-term follow-up ( r  = 0.66).

Conclusions  Computer navigated DFLOWO has satisfactory clinical outcomes and 79% survivorship in long-term follow-up. Presence of more than ICRS ≥ grade 2 degenerative changes in the medial compartment of knee with > 7° preoperative valgus deformity negatively affects the survivorship of DFLOWO in the long-term follow-up.

Factors Associated With Distal Femoral Osteotomy Survivorship: Data From the California Office of Statewide Health Planning and Development (OSHPD) Registry

Background:

Malalignment of the lower extremity can lead to early functional impairment and degenerative changes. Distal femoral osteotomy (DFO) can be performed with arthroscopic surgery to correct lower extremity malalignment while addressing intra-articular abnormalities or to help patients with knee osteoarthritis (OA) changes due to alignment deformities.

Purpose:

To examine survivorship after DFO and identify the predictors for failure.

Study Design:

Case series; Level of evidence, 4.

Methods:

Data from the California Office of Statewide Health Planning and Development, a statewide discharge database, were utilized to identify patients between the ages of 18 and 40 years who underwent DFO from 2000 to 2014. Patients with a history of lower extremity trauma, infectious arthritis, rheumatological disease, skeletal dysplasia, congenital deformities, malignancy, or concurrent arthroplasty were excluded. Failure was defined as conversion to total or unicompartmental knee arthroplasty, and the identified cohort was stratified based on whether they went on to fail. Age, sex, race, diagnoses, concurrent procedures, and comorbidities were recorded for each admission. Statistically significant differences between patients who required arthroplasty and those who did not were identified using the Student t test for continuous variables and a chi-square test for categorical variables. Kaplan-Meier survivorship curves were constructed to estimate 5- and 10-year survival rates. A Cox proportional hazards model was used to analyze the risk for conversion to arthroplasty.

Results:

A total of 420 procedures were included for analysis. Overall, 53 knees were converted to arthroplasty. The mean follow-up time was 4.8 years (range, 0.0-14.7 years). The 5-year survivorship was 90.2% (range, 85.7%-93.4%), and the 10-year survivorship was 73.2% (range, 64.7%-79.9%). The mean time to failure was 5.9 years (range, 0.4-13.9 years). Survivorship significantly decreased with increasing age (P = .004). Hypertension and a primary diagnosis of osteoarthrosis were significant risk factors for conversion to arthroplasty (odds ratio [OR], 3.12 [95% CI, 1.38-7.03]; P = .006, and OR, 2.42 [95% CI, 1.02-5.77]; P = .045, respectively), along with a primary diagnosis of traumatic arthropathy (OR, 10.19 [95% CI, 1.71-60.65]; P = .01) and a comorbid diagnosis of asthma (OR, 2.88 [95% CI, 1.23-6.78]; P = .02). Patients with Medicaid were less likely (OR, 0.11 [95% CI, 0.01-0.88]; P = .04) to undergo arthroplasty compared with patients with private insurance, while patients with workers’ compensation were 3.1 times more likely (OR, 3.08 [95% CI, 1.21-7.82]; P = .02).

Conclusion:

Older age was an independent risk factor for conversion to arthroplasty after DFO in patients ≥18 years but ≤60 years. Hypertension, asthma, and a diagnosis of osteoarthrosis or traumatic arthropathy at the time of surgery were predictors associated with failure, reinforcing the need for careful patient selection. The high survivorship rate of DFO in this analysis supports this procedure as a reasonable alternative to arthroplasty in younger patients with valgus deformities about the knee and symptomatic unicompartmental OA.

Effects of lateral opening wedge and medial closing wedge distal femoral osteotomies on axial load stability

BACKGROUND

The stability of the current distal femoral osteotomy is insufficient for early weight bearing and bone healing. The purpose of this study was to test the stability of medial closing wedge- (MCW-) and lateral opening wedge-distal femoral osteotomies (LOW-DFO), which have improved with the recent advances in technology.

METHODS

We used composite bone models with MCW-DFO, improved with biplanar osteotomy technique and a Tomofix™ MDF plate, or LOW-DFO improved with biplanar osteotomy technique, a Tomofix™ LDF plate, and a β-TCP bone substitute, BONISH® graft. A cyclic axial loading test was employed to evaluate the strain on a plate and hinge point. The breaking axial load was measured.

RESULTS

Tensile strain on the plate produced by cyclic axial loading was significantly lower for LOW-DFO (2.0 ± 0.8 MPa) than for MCW-DFO (3.9 ± 1.6 MPa, P < .05). Compressive strain on the hinge point produced by cyclic axial loading was lower for LOW-DFO (6.6 ± 2.9 MPa) than for MCW-DFO (7.7 ± 4.6 MPa,). The maximum breaking axial load was significantly higher for LOW-DFO (5511 ± 945 N) than for MCW-DFO (4303 ± 518 N, P < .05).

CONCLUSIONS

LOW-DFO improved with recent advanced technology was superior to MCW-DFO improved with advanced technology in both cyclic axial loading test and breaking axial load test. This suggests that LOW-DFO facilitates earlier weight bearing and bone healing than does MCW-DFO.

Opening-wedge osteotomies of the distal femur: minor advantages for a biplanar compared to a uniplanar technique

PURPOSE

Valgus malalignment of the distal femur may be treated with corrective osteotomy. The purpose of this study was to compare the primary stability of a lateral opening-wedge osteotomy (LOWO) using a uniplanar compared to a biplanar technique. A study was carried out to test both surgeries, with both an intact medial cortex and with a deliberate attached cut of the medial cortex simulating a fracture. The primary hypothesis was that the biplanar technique provides higher axial and torsional stiffness. It was further hypothesized that the mechanical superiority of the biplanar technique would not be affected in the case of breakage of the far medial cortex.

METHODS

A LOWO was performed in ten synthetic femora (#3406 left large Femur, 4th Generation, Sawbones, Malmö, Sweden) using a lateral angle stable locking plate (NCB© Distal Femur Plate, Zimmer Biomet, Warsaw, USA). A uniplanar osteotomy was performed in five femora, and a biplanar osteotomy was performed in five femora. The femora were tested for axial and torsional loads using a servo-hydraulic testing machine (Instron 8874, Instron Structural Testing GmbH, High Wycombe, UK).

RESULTS

Axial stiffness decreased significantly (p = 0.001) in both groups (20% in the uniplanar group and 28 % in the biplanar group) by cutting the medial cortex. The type of osteotomy had no significant effect. A slightly lower but not statistically significant axial stiffness was seen in the biplanar group both for intact and broken medial cortices. Internal torsional stiffness dropped by more than 30% for the uniplanar group and almost 24% for the biplanar group when the cortex was cut (p < 0.001). No significant change concerning internal torsional stiffness was found between the two groups. External torsional stiffness decreased by 32% for the uniplanar group and 4% for the biplanar group after the cortical cut (p = 0.029). No significant change concerning external torsional stiffness was found between the groups, but the biplanar group showed a tendency towards higher values of external torsional stiffness.

CONCLUSIONS

The axial and torsional stiffness of the implant-bone construct were not significantly affected by the type of osteotomy performed. Biplanar osteotomy tended to increase external torsional stiffness. In cases of fracture of the medial cortex, biplanar osteotomy significantly reduced the external rotation at the osteotomy and showed a significantly increased external torsional stiffness.

Total knee arthroplasty after distal femoral osteotomy long-term survivorship and clinical outcomes

Aims

There is little literature about total knee arthroplasty (TKA) after distal femoral osteotomy (DFO). Consequently, the purpose of this study was to analyze the outcomes of TKA after DFO, with particular emphasis on: survivorship free from aseptic loosening, revision, or any re-operation; complications; radiological results; and clinical outcome.

Patients and Methods

We retrospectively reviewed 29 patients (17 women, 12 men) from our total joint registry who had undergone 31 cemented TKAs after a DFO between 2000 and 2012. Their mean age at TKA was 51 years (22 to 76) and their mean body mass index 32 kg/m2 (20 to 45). The mean time between DFO and TKA was ten years (2 to 20). The mean follow-up from TKA was ten years (2 to 16). The prostheses were posterior-stabilized in 77%, varus-valgus constraint (VVC) in 13%, and cruciate-retaining in 10%. While no patient had metaphyseal fixation (e.g. cones or sleeves), 16% needed a femoral stem.

Results

The ten-year survivorship was 95% with aseptic loosening as the endpoint, 88% with revision for any reason as the endpoint, and 81% with re-operation for any reason as the endpoint. Three TKAs were revised for instability (n = 2) and aseptic tibial loosening (n = 1). No femoral component was revised for aseptic loosening. Patients under the age of 50 years were at greater risk of revision for any reason (hazard ratio 7; p = 0.03). There were two additional re-operations (6%) and four complications (13%), including three manipulations under anaesthetic (MUA; 10%). The Knee Society scores improved from a mean of 50 preoperatively (32 to 68) to a mean of 93 postoperatively (76 to 100; p < 0.001).

Conclusion

A cemented posterior-stabilized TKA has an 88% ten-year survivorship with revision for any reason as the endpoint. No femoral component was revised for aseptic loosening. Patients under the age of 50 years have a greater risk of revision. The clinical outcome was significantly improved but balancing the knee was challenging in 13% of TKAs requiring VVC. Overall, 10% of TKAs needed an MUA, and 6% of TKAs were revised for instability. Cite this article: Bone Joint J 2019;101-B:660–666.

Ex vivo evaluation of a novel surgical guide on the accuracy of closing wedge osteotomies

OBJECTIVE

To determine the influence of a novel surgical guide on the accuracy and technical difficulty of closing wedge osteotomies (CWO).

STUDY DESIGN

Ex vivo experimental study.

SAMPLE POPULATION

Canine tibia models (n = 40).

METHODS

A 20° cranial CWO (CCWO) was created without (standard procedure; STCCWO) or with the aid of a novel wedge osteotomy guide (WOCCWO). Procedures were performed by diplomate (n = 4) and resident (n = 6) surgeons, with each performing 2 STCCWO followed by 2 WOCCWO. To prevent bias, surgeons were unaware of the study purpose until after completing the STCCWO. The wedges were evaluated by comparing the deviation from the 20° target angle, divergence of the 2 osteotomies (osteotomy divergence angle [ODA]), and measurements of the wedge height at the caudomedial cortex (CMC) and caudolateral cortex (CLC). Technique difficulty was explored through a surgeon questionnaire.

RESULTS

The WOCCWO resulted in smaller mean ODA (WOCCWO = 0.86°, SD ± 0.38°, P < .001), and smaller mean difference between CMC and CLC (WOCCWO = 0.29 mm, SD ± 0.19, P < .001) than for the STCCWO (4.22°, SD ± 2.16° and 1.39 mm, SD ± 0.65 respectively). Deviation from the target 20° wedge angle was greater after STCCWO (1.46°, SD ± 1.27°) than after WOCCWO (0.53°, SD ± 0.33°, P = .004). No difference was reported regarding the difficulty of the procedures, but resident surgeons stated that they were more likely to use the guide in a clinical setting compared with diplomates.

CONCLUSION

The wedge osteotomy guide improved the accuracy of CCWO compared with standard technique.

CLINICAL SIGNIFICANCE

The clinical significance of the differences detected in this study is unclear and warrants in vivo investigation.

Medial Open-wedge Osteotomy with Double-plate Fixation for Varus Malunion of the Distal Femur

Objective

To present our clinical experience of treating varus malunion of the distal femur through a medial open‐wedge osteotomy with double‐plate fixation.

Methods

A prospective cohort study was performed. From January 2005 to February 2015, 15 consecutive patients with varus malunion following distal femur fractures were surgically treated at a single level I trauma center. The coronal and sagittal deformity were corrected by a medial open‐wedge osteotomy of the distal femur. A medial buttress plate was used to maintain the realignment. A lateral locking plate was additionally used as a protection plate. The mean age of patients at the time of the surgery was 35.5 years (range, 22–58 years). The radiographical evaluation included the mechanical femorotibial angle, the mechanical lateral distal femoral angle, the anatomic posterior distal femoral angle, and the leg length discrepancy. Clinical outcome evaluation consisted of the range of motion (ROM) and Hospital for Special Surgery (HSS) score.

Results

Mean follow‐up was 7.4 years (range, 4–11.5 years). Varus and flexion malalignment and limb discrepancy were adequately corrected in all patients. The mechanical femorotibial angle, the mechanical lateral distal femoral angle, and the anatomic posterior distal femoral angle were restored from 17.5° (range, 13°–25°) to 2.3° (range, − 2°–7°), 102.3° (range, 95°–112°) to 85.2° (range, 81°–92°), and 77.1° (range, 65°–87°) to 82.7° (range, 76°–88°), respectively. The leg length discrepancy was diminished from 3.4 cm (range, 2.4–4.5 cm) to 0.8 cm (range, 0–1.7 cm). The average bone healing time was 4.1 months (range, 2.5–6 months). The average ROM of the affected knees at 24‐month follow‐up was 3.4°–112.55°. The score of HSS at 4‐years follow‐up was 76.1 (range, 64–88). No internal fixation failure or secondary operation was noted until the last follow‐up.

Conclusion

Medial open‐wedge osteotomy can adequately correct the posttraumatic varus malunion of the distal femur. With fixation of the double plate, non‐displaced bone healing and good functional outcome are expected.

Smoking and obesity influence the risk of nonunion in lateral opening wedge, closing wedge and torsional distal femoral osteotomies

PURPOSE

Lateral distal femoral osteotomies (DFO) have recently been performed more frequently. In addition to realignment for varus and valgus deformity, the indication was extended with the introduction of torsional osteotomies in patellofemoral instability. The purpose of this study was to assess the general and technical risk factors for nonunion in lateral opening, closing and torsional DFO.

METHODS

A total of 150 lateral DFO [98 opening wedge (LOWDFO) and 52 closing wedge (LCWDFO)] were analyzed in regard to potential risk factors for nonunion until plate removal. Nonunion was defined as failure of osseous consolidation according to clinical and radiological evaluation.

RESULTS

In LOWDFO, the nonunion rate was 2%, in LCWDFO the rate was higher with 9.6%. Nicotine abuse (p = 0.009) and a higher body mass index (p = 0.003) were significant risk factors. Patient's age and gender, the wedge height, hinge fractures, monoplanar versus biplanar osteotomy as well as additional torsional osteotomies were not significant in regard of nonunion.

CONCLUSIONS

Lateral DFO have a low rate of complications and nonunion. Smoking and obesity were significantly associated with the risk of nonunion. Hinge fractures, monoplanar technique or complete bone cuts of the opposite hinge in torsional osteotomies did not negatively influence the nonunion rate in DFO.

LEVEL OF EVIDENCE

Level IV.

Effect of Increased Coronal Inclination of the Tibial Plateau After Opening-Wedge High Tibial Osteotomy

PURPOSE

To assess whether the increased inclination of the tibial plateau on the coronal view after opening-wedge high tibial osteotomy affects radiographic coronal alignment, clinical outcomes, and cartilage findings.

METHODS

After adjustment for the preoperative medial proximal tibial angle (MPTA), patients who underwent opening-wedge high tibial osteotomy were retrospectively divided into those with postoperative MPTA values of 95° or less (normal group) and greater than 95° (increased group), with each group containing 43 knees. The 2 groups were compared regarding their arthroscopic cartilage findings at 1 year postoperatively and radiographic coronal alignment and clinical outcomes at 2 years postoperatively. Cartilage regeneration in the medial condyles and cartilage deterioration in the lateral condyles were evaluated at the time of second-look arthroscopy. Clinical outcomes were evaluated by the American Knee Society knee and function scores, Lysholm knee scoring scale, and Knee Injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

The postoperative anatomic femorotibial angle in the increased group was lower than that in the normal group (P < .001), and the amount of overcorrection in the increased group was higher than that in the normal group (P < .001). The postoperative joint line obliquity in the increased group was higher than that in the normal group (P < .001). Cartilage regeneration in the medial condyles and deterioration in the lateral condyles did not differ significantly on the femoral and tibial sides between the groups. The postoperative American Knee Society knee score and KOOS sports and recreational function subscale score in the normal group were higher than those in the increased group (both P < .001).

CONCLUSIONS

There were no significant differences in the changes in the appearance of the articular surfaces between the 2 groups at 1 year postoperatively. Patients with a postoperative MPTA greater than 95° had more valgus alignment and higher joint line obliquity and had a lower KOOS sports and recreational function subscale score than patients with a postoperative MPTA of 95° or less at 2 years postoperatively.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Three dimensional patient-specific printed cutting guides for closing-wedge distal femoral osteotomy

PURPOSE

Medial closing-wedge distal femoral osteotomy (MCWDFO) was used to treat valgus knee malalignment combined with lateral compartment disease. The clinical outcome of the osteotomy depends on the accurate correction of valgus malalignment. The aim of this study was to evaluate the accuracy of a MCWDFO assisted by three-dimensional (3D)-printed cutting guides and locking guides.

PATIENTS AND METHODS

Thirty-three consecutive patients (33 knees) were operated on using the same MCWDFO. 3D-printed cutting guides and locking guides were used to locate the osteotomy cut plane and to facilitate closing the wedge in 12 patients (3D-guide group). Another 21 patients (conventional group) underwent MCWDFO following the conventional technique. The desired correction was defined as a weight-bearing line (WBL) coordinate 50% of the width of the tibial plateau from the medial tibial margin. The deviation between the planned and executed WBL coordinate, surgical time and fluoroscopic time were compared.

RESULTS

The mean deviation between the planned and executed WBL coordinate was 4.9% in the 3D-guide group and 7.6% in the conventional group (P = 0.024). Shorter surgical time was found in the 3D-guide group (mean, 77.7 minutes vs. mean, 96.5 minutes; P < 0.001), while the mean number of intra-operative fluoroscopic images was 6.1, compared with 34.7 in the conventional group (P < 0.001).

CONCLUSION

The use of 3D-printed cutting guides and locking guides can increase the precision of the MCWDFO in patients with lateral compartment disease and valgus deformity, making our surgery more efficiency and occupying less fluoroscopic time.

Distal Femoral Varus Osteotomy for Valgus Arthritis of the Knees: Systematic Review of Open versus Closed Wedge Osteotomy

Purpose

The purpose of this review is to compare the clinical and radiological outcomes between open and closed wedge distal femoral varus osteotomy (DFO).

Methods

A literature search of online databases (MEDLINE, EMBASE, and Cochrane Library database) was made in addition to manual search of major orthopedic journals. Data were searched from the time period of January 1990 to October 2016. A modified Coleman Methodology Score system was used to assess the methodologic quality of the included studies. A total of 20 studies were included in the review. All studies were level IV evidence.

Results

Comparative analysis of open and closed wedge DFO did not demonstrate clinical and radiological differences. The survival rates were also similar. Five studies (56%) on open wedge DFO mentioned the need for either bone grafting or substitute for osteotomy gap filling and reported higher incidences of reoperation for plate removal than the closed wedge DFO studies.

Conclusions

The present systematic review showed similar performance between open and closed wedge DFO. Outcomes including survival rates were not statistically significantly different. However, additional bone grafting or substitutes were often needed to prevent delayed union or nonunion for open wedge techniques. Additional operations for plate removal were commonly required due to plate irritation in both techniques.

Three dimensional-printed patient-specific cutting guides for femoral varization osteotomy: Do it yourself

INTRODUCTION

In valgus knees of young patients, opening-wedge distal femoral osteotomy is a valid treatment option for axial corrections. It allows the surgeon to achieve accurate correction, which is directly related to the functional outcome and survivorship of the osteotomy. This study presents a new technique based on three-dimensional (3D)-printed cutting guides for opening-wedge distal femoral osteotomies, in which pre-operative planning and intraoperative executional accuracy play a major role.

MATERIAL AND METHODS

Pursuing axial correction accuracy, 3D-printed patient-specific positioning guides and wedge spacers were both created and used by the surgeon to implement the femoral osteotomy. The proposed technique was performed in 12 consecutive patients (cases). The results were compared with 20 patients (controls) in which opening-wedge distal femoral osteotomies were performed following the traditional technique. Accuracy of the axial correction, surgical time, fluoroscopic time and costs were measured.

RESULTS

More accurate axial correction with reduced surgical time (32min less), intraoperative fluoroscopic images (59 images less) and costs (estimated €412 less) were achieved with the use of the customized guides when compared with the traditional technique.

DISCUSSION

Accurate correction of the axial alignment of the limb is a critical step in survivorship of the osteotomy. Improving the technique to enhance accuracy focused on this issue.

CONCLUSIONS

The use of patient-customized cutting guides minimised human error; therefore, surgical time was reduced and accurate axial correction was achieved. The surgeon mastered all steps in a do-it-yourself philosophy style.

[Distal femoral osteotomy using a lateral opening wedge technique]

OBJECTIVE

To shift the weight-bearing axis of the lower limb medially by opening a lateral-based metaphyseal osteotomy at the distal femur.

INDICATIONS

Femoral-based valgus malalignment and symptomatic lateral unicompartimental osteoarthritis, lateral hyperpression syndrome, cartilage therapy of the lateral compartment, lateral meniscal replacement/transplantation, medial instability with valgus thrust, reconstruction of the medial collateral ligament, patellar instability and/or maltracking.

CONTRAINDICATIONS

Advanced cartilage damage (>grade 2) or subtotal meniscal loss of the medial compartment, age >65 years (relative), nicotine abuse, body mass index >30, flexion contracture >25°, corrections with a wedge base >10 mm in case of congenital deformities, inflammatory or septic arthritis, severe osteoporosis.

SURGICAL TECHNIQUE

Lateral approach to the distal femur; biplanar osteotomy (frontal + axial osteotomy), gradual opening of the osteotomy, osteotomy fixation with a locking plate.

POSTOPERATIVE MANAGEMENT

Free range of motion. Partial weight bearing with 20 kg for 2 weeks, followed by progressive weight bearing thereafter.

RESULTS

Mean improvement of knee scores from 20-30 points and mean 10-year survival rate of 80% in patients with lateral unicompartimental osteoarthritis. Mean complication rate of 9%.

Nonunion and delayed union in lateral open wedge distal femoral osteotomies-a legitimate concern?

INTRODUCTION

Due to a supposed high rate of nonunions in lateral open wedge distal femur osteotomy (LOWDFO), the medial closing wedge technique has been favoured for a long time. The aim of this study was to report the occurrence of delayed- and nonunions following LOWDFO. We hypothesized that the occurrence of nonunions needing revision surgery is comparable to medial closing osteotomies.

METHODS

Forty-one patients were treated with LOWDFO with a minimum follow-up of 12 months. Parameters such as age, gender, body mass index, valgus angle, the heights of the opening wedge, as well as the type of osteotomy (biplane vs single plane) were collected. Delayed union and nonunion were evaluated on radiographs along with clinical symptoms.

RESULTS

The study group consisted of 21 females and 20 males, with a median age of 37 years at the time of surgery. Removal of hardware was performed in 63% after 1.3 years (0.6-2.1 years). The median preoperative valgus angle was 6.1° valgus (range 2-15.5°). The heights of the opening wedge ranged from 2 to 12 mm (mean 5.3 mm). Hinge fracture of the medial cortex was seen in 39%. Three patients had a delayed union, and one patient had a nonunion requiring revision surgery.

CONCLUSION

LOWDFO is a safe alternative to MCWDFO. Although radiolucency of the osteotomy gap can be evident on radiographs even after 12 months, this does not reflect the clinical finding. The nonunion rate is proven to be low and comparable with the nonunion rates of MCWDFOs as well as open wedge HTOs.