Deformity Correction: Do Osteochondral Lesion of the Talus and Tibia Change After Realignment Surgery?

Malalignment of the lower limb, distal tibia, foot, and hindfoot can all contribute to altered biomechanics in the ankle joint, resulting in increased focal pressure. The development of some osteochondral lesions of the ankle joint may share a similar pathophysiology, where eccentric loading to the talus or tibia within the ankle joint can lead to cartilage injury or adaptive changes. While the association between malalignment and the development of osteochondral lesions of the ankle joint may seem intuitive, the impact of realignment procedures on these lesions and patient symptoms remains a relatively underexplored topic in the literature. A comprehensive understanding of the potential role of realignment surgery in managing osteochondral lesions of the talus and tibia is crucial for advancing our knowledge of this challenging pathologic condition.

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.

Coronal Alignment in Adult Spine Surgery.

Coronal realignment is an important goal in adult spine surgery that has been overshadowed by emphasis on the sagittal plane. As coronal malalignment drives considerable functional disability, a fundamental understanding of its clinical and radiographic evaluation and surgical techniques to prevent its development is of utmost importance. In this study, we review etiologies of coronal malalignment and their radiographic and clinical assessments, risk factors for and functional implications of postoperative coronal malalignment, and surgical strategies to optimize appropriate coronal realignment in adult spine surgery.

Editorial Commentary: Absent Extreme Bony Malalignment: Medial Patellofemoral Reconstruction Is a Sufficient Primary Surgery for Adolescents With Recurrent Patella Instability.

When planning an adolescent's primary surgery for recurrent patella instability, the surgeon must weigh the failure risk of performing medial patellofemoral reconstruction (MPFLR) versus the potential morbidity of adding a concomitant bony procedure, such as tibial tubercle osteotomy. In this age group, isolated MPFLR is an excellent operation with high clinical success, low failure rates, and favorable complication profile. Patients with high grade J-sign and severe trochlea dysplasia, apprehension into deep flexion, and extremes of bony malalignment, including elevated tibial tubercle-trochlear groove distance, may benefit from "doing more" than MPFLR alone. Other factors to be considered include patella alta, generalized ligament laxity, femoral rotation, tibial torsion, and valgus malalignment. In challenging situations, such as syndromic patients (e.g., neuromuscular disorders), congenital (habitual) patella dislocation, fixed dislocations, and failed prior to MPFLR, a combined surgical approach is likely needed. Patients who require "unloading" for symptomatic chondrosis also benefit from combined bony and soft tissue surgery. However, for the majority of patients with recurrent instability and no prior surgery, an isolated soft tissue reconstruction is a rational, safe, efficient, and evidence-based selection.

Effects of preoperative sagittal spinal imbalance on pain after lateral lumbar interbody fusion.

Sagittal misalignment has been associated with negative quality of life (QOL). However, there is no report on whether differences in preoperative sagittal misalignment in patients with lumbar degenerative diseases affect postoperative results after lateral lumbar interbody fusion (LLIF). We investigated whether preoperative sagittal alignment influences the correction of alignment after surgery and whether the preoperative sagittal alignment affects the rating of low back pain, leg pain, and leg numbness. The subjects were 81 patients (48 male, 33 females, average age at surgery 70.2 years) who underwent anterior-posterior combined surgery with LLIF and percutaneous pedicle screws from May 2018 to July 2020. Cluster analysis was performed using the preoperative sagittal vertical axis (SVA) value, and patients were classified into two groups (group 1; n = 30, SVA = 129.0 ± 53.4 mm, group 2; n = 51, SVA = 30.8 ± 23.5 mm). Baseline demographics and treatment data were compared between groups. Sagittal and pelvic parameters and pain scores, such as low back pain, leg pain, and leg numbness, were also compared. Operative time, blood loss, and length of hospital stay did not differ significantly between groups. The changes (Δ) in SVA and lumbar lordosis (LL) for all patients from before to after surgery were not significant (ΔSVA; p = 0.218, ΔLL; p = 0.189, respectively). The SVA, LL, and PI - LL changed significantly after the surgery in group 1, but no marked improvement in sagittal imbalance was obtained after LLIF surgery. The improvement in each pain score from before to after the surgery did not differ significantly between groups. LLIF surgery has a limited chance of recovering sagittal imbalance. However, postoperative low back pain, leg pain, and leg numbness may be improved by LLIF surgery, regardless of the preoperative sagittal alignment.

Repositional Subtalar Arthrodesis Combined With Supramalleolar Osteotomy for Late-Stage Varus Ankle Arthritis With Hindfoot Valgus.

BACKGROUND: Late-stage varus ankle arthritis is thought to be associated with varus of the tibial plafond and hindfoot. However, some late-stage varus arthritis show hindfoot valgus, which can be explained by subtalar subluxation with opposite directional motion between the talus and calcaneus. We hypothesized that late-stage varus ankle arthritis with hindfoot valgus could improve with repositional subtalar arthrodesis and supramalleolar osteotomy (SMO). The purpose of this study was to investigate the clinical and radiographic results of the repositional subtalar arthrodesis combined with SMO for late-stage varus ankle arthritis with hindfoot valgus. METHODS: This study includes 16 consecutive patients (16 ankles) with late-stage varus ankle arthritis of Takakura stage 3-b and hindfoot valgus who were treated using repositional subtalar arthrodesis combined with SMO and followed for a minimum of 2 years. Clinical results were assessed with the visual analog scale (VAS) and the Foot Function Index (FFI). Radiographic results were assessed with standard parameters measured on weightbearing foot and ankle radiographs. Clinical and radiographic results were evaluated preoperatively and at the last follow-up. RESULTS: VAS and FFI significantly improved after surgery. Mean talar tilt angle improved from 12.8 ± 2.8 degrees to 3.9 ± 3.1 degrees (P < .001). Talus center migration and Meary angle significantly improved after surgery. Medial distal tibial angle, lateral talocalcaneal angle, hindfoot moment arm, and talonavicular coverage angle significantly changed after surgery. Radiographic stage improved in 15 ankles (93.8%) after surgery. CONCLUSION: In this series with minimum 2-year follow-up, we found that late-stage (Takakura stage 3-b) varus ankle arthritis with hindfoot valgus clinically and radiographically improved with repositional subtalar arthrodesis combined with SMO. LEVEL OF EVIDENCE: Level IV, prognostic.

Impact of Internal Malrotation of the Femur Followed by Derotational Osteotomy as Demonstrated by 3D Gait Analysis: A Case Report.

CASE: An 18-year-old man with 48° of internal malrotation of the femur after nailing underwent derotational osteotomy with gait dynamics and electromyography data collected preoperatively and postoperatively. Hip abduction and internal foot progression angles were significantly deviated from normal preoperatively compared with the contralateral side. At 10 months postoperatively, the hip was abducted and externally rotated throughout the entire gait cycle. His Trendelenburg gait had resolved, and he reported no residual functional concerns. Before corrective osteotomy, walking velocity was significantly slower with shorter stride lengths. CONCLUSION: Significant internal malrotation of the femur impairs hip abduction and foot progression angles as well as gluteus medius activation during ambulation. Derotational osteotomy considerably corrected these values.

Use of Lesser Trochanter Profile as a Rotational Alignment Guide in Intramedullary Nailing for Femoral Shaft Fracture.

BACKGROUND: Malrotation after nailing of femoral shaft fractures occurs in about 25% of cases. It can cause substantial functional problems. The lesser trochanter (LT) profile has been used to assess rotational alignment. However, the extent to which the LT profile is symmetrical between limbs, whether the LT profile varies as a function of age or sex, and the efficacy of the LT profile technique remain unknown. The purpose of this study was to determine if there was a significant side-to-side length difference in the LT profile (LTD) according to age and sex. METHODS: We attempted to determine the amount of medial prominence of the lesser trochanter relative to the medial cortex of the femoral shaft (the LT profile) using 3-dimensional computed tomography (3D-CT) images of normal femora obtained bilaterally (366 subjects) in anatomic positions. We also compared the left and right sides to determine the amount of natural asymmetry by age and sex. In addition, we compared the side-to-side difference in the LT version with the LTD to determine whether the LTD represented the difference in femoral rotation. RESULTS: The LTD was <4 mm (meaning an LT version difference of <10°) in 83% of the subjects, but was ≥4 mm (an LT version difference of ≥10°) in 17%. Subset analysis demonstrated that the differences were greatest in women >70 years of age. The largest LTD (both sexes) was observed in individuals over 70 years of age (2.62 ± 1.37 mm, compared with <55 years: 1.55 ± 1.36 mm and 55 to 70 years: 2.27 ± 1.70 mm). There was no significant difference between sexes in the under-70 age groups. However, the LTD was significantly greater in women over 70 years than in men over 70 years (3.10 ± 1.42 versus 2.41 ± 1.30 mm). CONCLUSIONS: Since the LTD demonstrated side-to-side symmetry within 4 mm, or 10° of rotation, in 83% of all subjects, we consider the LT profile to be useful as a guide to assess rotational reduction clinically. However, surgeons should recognize that, in 17% of cases, using this technique could result in malrotation of ≥10°. The rate of malrotation may be even higher in women over 70, for whom supplemental techniques to ensure correct rotation may be appropriate.

Transiency of postoperative cervical kyphosis seen after surgical correction of sagittal malalignment in adult spinal deformity patients.

OBJECTIVE: In this study, we evaluated factors affecting changes in cervical lordosis after deformity correction and during follow-up period in adult spinal deformity (ASD) patients with severe sagittal imbalance. METHODS: Seventy-nine patients, with an average age of 71.6 years, who underwent long-segment fixation from T10 to S1 with sacropelvic fixation were included. We performed a comparative analysis of the radiographic parameters after surgery (Post) and at the last follow-up (Last). We calculated the Pearson's correlation coefficient and performed multilinear regression analysis to predict independent parameters for Post and Last cervical lordosis (CL), T1 slope (T1S), and thoracic kyphosis (TK). RESULTS: Hyperlordotic changes of -23.3° in CL before surgery was reduced to -7° after surgery, and Last CL had increased to -15.3°. T1S was reduced from 27° before surgery to 14.4° after surgery and had increased to 18.8° at the last follow-up. Through multilinear regression analysis, we found that Post CL and T1S were more significantly affected by the amount of LL correction (p = .045 and .049). The effect of Last T1S was significantly associated with the Last CL; the effect of Last TK, with the Last T1S; and the effect of Post PI-LL, with the Last TK (p < .05). CONCLUSION: The postoperative kyphotic change in CL in ASD patients with preoperative cervical hyperlordosis is not permanent and is affected by drastic LL correction and SVA restoration. To achieve spinopelvic harmony proportional to the difference in LL relative to PI, TK becomes modified over time to increase T1S and CL, in an effort to achieve optimal spine curvature.

[Radiographic analysis of limb malalignment in the frontal plane]. / Radiologische Analyse von Achsfehlstellungen des Knies in der Frontalebene.

Radiographic measurement of the lower limb alignment in the frontal plane is used to assess limb deformity, to plan corrective surgery and for follow-up. It is essential that age-related normal lower limb alignment and joint orientation angles are known before planning surgical treatment. EOS (EOS™ Imaging, Paris, France) can lead to supplemental information, especially in cases of severe multidimensional joint malalignment. It allows 3D reconstruction of a bone model of the limb to assess multi-dimensional deformity.

High tibial osteotomy performed with PEEK implant demonstrated a failure rate of 28.

OBJECTIVES: Opening-wedge high tibia osteotomies (HTO) can be technically challenging. The HTO iBalance system was designed to reduce vascular complications and to avoid secondary plate removal. The purpose of the study was to evaluate the performance of the HTO iBalance system in patients with symptomatic medial osteoarthritis and varus malalignment. METHODS: The study was performed as a retrospective cohort study investigating a consecutive series of patients who underwent HTO with the iBalance system performed by a single surgeon from August 2013 to March 2016 at Zealand University Hospital, Koege, and Aleris-Hamlet Hospital. The primary outcome was the degree of realignment. The secondary outcome was Knee injury and Osteoarthritis Outcome Score (KOOS). Follow-up was performed at mean (SD) 25 (9.7) months. Weight-bearing long-leg standing radiographs were taken before surgery and at follow-up. Failure was defined as collapse of the HTO defined as a correction <50% of the intended correction at time of follow-up. Logistic regression was used to identify risk factors for failure. RESULTS: 44 patients and a total of 47 knees were included in this study. Preoperatively the mechanical axis was a mean (SD) 5.8° (2.9) varus and postoperatively 2.3° (3.7) varus . The HTO failed in 13 of 47 knees (28%). Patients with failure showed no statistically significant differences to non-failure in any KOOS subscore (p>0.05). American Society of Anesthesiologists (ASA) score (p=0.01) and body mass index (BMI) (p=0.05) were correlated with failure, whereas bone transplantation and smoking were not. CONCLUSION: In this study, the failure rate of HTO was 28%. High BMI and ASA-score were the only risk factors associated with failure while bone grafting and smoking were not. LEVEL OF EVIDENCE: Retrospective cohort study, level III.

Correction of coronal plane deformities around knee in children with two-hole tension band plates.

OBJECTIVES: This study aims to present the 10-year results and complications of two-hole tension band plate hemiepiphysiodesis for coronal deformities around knee in a large population from a single center. PATIENTS AND METHODS: Seventy-seven patients (46 boys, 31 girls; mean age 93±36 months; range, 22 to 181 months) who underwent temporary hemiepiphysiodesis around knee between January 2009 and January 2019 with two-hole tension band plates were retrospectively evaluated. Improvement of joint orientation angles and mechanical axis deviations, deformity correction rates, etiology groups, and complications were noted. RESULTS: A total of 166 bone segments (93 femurs, 73 tibias) were included in the study. Mean follow-up duration after the implantation was 36±17 (range, 12 to 88) months. Plates were removed at mean 18±8 (range, 7 to 47) months of implantation. Of the bone segments, 95.2% (n=158) responded successfully to the plates. Mean correction rate of mechanical lateral distal femoral angle in femoral valgum deformity was 0.94±0.43° (range, 0.17 to 2.22)/month and mean correction rate of mechanical medial proximal tibial angle in tibial valgum deformity was 0.62±0.36° (range, 0.11 to 1.55)/month. Mean correction rate of mechanical lateral distal femoral angle in femoral varum deformity was 1.3±0.8° (range, 0.48 to 2.92)/month and mean correction rate of mechanical medial proximal tibial angle in tibial varum deformity was 0.94±0.49° (range, 0.26 to 1.67)/month. The most common complication observed was rebound deformity seen in 41.2% (n=70) of the bone segments. Nine bone segments had persistent hemiepiphysiodesis despite plate removal. Four screw breakages (three metaphysial and one epiphysial) were observed. CONCLUSION: Two-hole tension band plate hemiepiphysiodesis appears to be an effective and safe method for the correction of coronal deformities around knee.

Lower Limb Malrotation Is Regularly Present in Long-Leg Radiographs Resulting in Significant Measurement Errors.

Weight-bearing long-leg radiographs are commonly used in orthopaedic surgery. Measured parameters, however, change when radiographs are conducted in different rotational positions of the leg. It was hypothesized that rotational errors are regularly present in long-leg radiographs resulting in wrong measurements. In 100 consecutive long-leg radiographs conducted according to the method of Paley, rotation was assessed by fibular overlap. Angular parameters in radiographs (mechanical lateral proximal femoral angle (mLPFA), mechanical lateral distal femoral angle (mLDFA), angle between the anatomical and mechanical femoral axis (AMA), mechanical medial proximal tibia angle (mMPTA), mechanical lateral distal tibial angle (mLDTA), and the mechanical femoral and tibial axis (mFA-mTA) were measured and deviations related to malrotation calculated. An average internal rotation of 8 degrees was found in lower limbs showing a range between 29 degrees of internal and 22 degrees of external rotation. As a result, mean differences before and after rotational correction for measured parameters (mLPFA, mLDFA, AMA, mMPTA, mLDTA, mFA-mTA) ranged between 0.4 and 1.7 degrees (-2.1; 5.6 95% confidence interval [CI]). In conclusion, malrotation of lower limbs is regularly present in long-leg radiographs. As all measured parameters are influenced by malrotation, correct lower limb rotation needs to be verified.

Effectiveness of Using Photographs of the Change in Standing Posture on Postoperative Patient-Reported Satisfaction and Quality of Life.

Dissatisfaction is still an important problem in a small but important group of patients who undergo total knee arthroplasty. This study was designed to evaluate the effectiveness of showing patients the change in their standing posture, before and after total knee replacement, using standing photographs (anterior, posterior, and lateral view), on improving self-reported quality of life and satisfaction. Full-length lower extremity radiographs and standing photographs were obtained prior to total knee replacement and 6 months after surgery in the study group. In the control group, radiographs and photographs were not obtained. The hip-knee-ankle angle and mechanical axis deviation were compared between the two limbs and two groups. The changes in the following outcome measures were evaluated from baseline to 6 months after surgery: Short Form-36 Survey, Knee Injury and Osteoarthritis Outcome Score, Western Ontario and McMaster Universities Osteoarthritis Index, Oxford Knee Score, and Knee Society score. Postoperative measures were also compared before and after showing patients their standing photographs, and between two groups. The study and control groups included 71 and 44 patients, respectively, with unilateral or bilateral knee osteoarthritis (Kellgren-Lawrence Grade 3 or 4), with a mean age of 66 years. All patients had a varus malalignment, with significant improvement in postoperative limb alignment (p < 0.001). All self-reported outcome measures improved after surgery (p < 0.05), with the exception of mental health in the Short Form-36. Self-reported scores further improved after patients seeing their standing photographs (p < 0.05), with the exception of mental health and social role functioning. There were also significantly improved scores in the study group than control group after showing photographs (p < 0.05). Showing patients the pre-to-postoperative change in their standing posture might be an easy-to-administer method to improve patient satisfaction with the outcome of total knee replacement and self-reported quality of life. The Level of Evidence for this study is four.

High Medium-Term Survivorship of Cruciate-Retaining Total Knee Arthroplasties (110 Knees) for Valgus Deformity.

The main purpose of this article is to evaluate the clinical outcomes and survivorship of cruciate-retaining (CR) knee arthroplasties for valgus deformity. This article is retrospective consecutive series of 110 valgus knees using CR implants with a minimum 2-year follow-up. Deformity correction was achieved using stepwise sequential soft tissue releases (iliotibial band, popliteus tendon, lateral collateral release through sliver femoral condylar osteotomy). Demographic data, range of movement, and degrees of deformity were collected. The Oxford Knee Score (OKS) was used as patients' reported outcome measure at final follow-up. One-hundred and four patients (110 knees) were included (87 females/17 males) with mean age of 68.7 years. Primary diagnosis was osteoarthritis in 85 patients and rheumatoid arthritis in 19 patients. Mean follow-up was 5.5 years (median: 5 years; range: 2-14 years). Preoperative valgus deformity was measured radiographically using the mechanical tibiofemoral angle with a mean 18.6° (standard deviation [SD]: 7.5; range: 11-38°). At final follow-up, mechanical tibiofemoral angle was 3.8° (SD: 1.97; range: 2-8°). A p-value was <0.0001 and mean OKS was 42 (SD: 5.4; range: 36-48) suggesting satisfactory patients' reported outcomes with no implant revision for any cause. CR implants for valgus knees using staged soft tissue releases including sliver condylar osteotomy had excellent medium-term survivorship and satisfactory patient reported outcome measures. The Level of Evidence for this study is IV.

Focal inlay resurfacing for full-thickness chondral defects of the femoral medial condyle may delay the progression to varus deformity.

INTRODUCTION: Full-thickness chondral defects at the knee joint predispose to the beginning of a degenerative process which final consequence is the compartment collapse and finally the deviation to varus, because the cartilage of the medial femoral condyle is the most frequently affected area. Likewise, people with these chondral defects are more likely to develop tricompartmental osteoarthritis, reason why early surgical management should be the treatment of choice. The aim of this study was to compare the pre- and post-operative lower limb alignment (mechanical axis), in cases of full-thickness chondral defects of the femoral medial condyle that have been managed by means of a prosthetic focal inlay resurfacing, at a minimum follow-up of five years. METHODS: A retrospective study of patients treated for chondral defects in the medial femoral condyle was performed. The inclusion criteria were patients who had undergone a focal inlay resurfacing and minimum follow-up of 5 years. Patients that required a concomitant valguizing tibial osteotomy were finally excluded. The follow-up analysis was performed by means of radiological examinations performed prior to surgery and at the last follow-up visit. The mean limb mechanical axis of the operated knees was calculated both pre- and post-operatively, and comparisons between these two settings were performed. RESULTS: Ten patients were included: eight men and two women. The mean age at the time of surgery was 55 (40-65) years. The mean follow-up was 9 years (range 5-15). The mean limb mechanical axis was 1.33 ± 4.16 in the pre-operative setting and 2.40 ± 5.50 in the post-operative setting (p = 0.441). CONCLUSION: In the setting of small to moderate size, unique femoral medial condyle full-thickness chondral lesions, filling the defect with an inlay prosthetic resurfacing may protect against the progression to varus deformity. LEVEL OF EVIDENCE: Therapeutic case series, Level IV.

Intra-individual variance of bilateral femoro-tibial leg rotation: a CT study of 105 healthy subjects.

PURPOSE: In cases of suspected rotational deformity of the lower limb, in particular in post-traumatic malalignment following closed nailing, there is a lack of adequate reference values. Available publications on leg rotation have either small sample sizes or do not include bilateral or whole leg rotation of healthy legs. This study aimed to determine side-specific reference values of lower limb rotation in a large healthy sample. This may be helpful in acute clinical settings as well as for medical expert opinion. METHODS: 226 consecutive bilateral lower limb computed tomography (CT) angiographies were screened. 105 patients (210 legs) were included (40 females, 65 males, mean age 67 ± 12 years). Bilateral axial femoral and tibial rotation alignment were independently measured and overall leg rotation was computed by two methods. Distributions, sex, and side differences were analyzed. RESULTS: Two-sided paired t tests showed significant differences between right and left for all measurements. The left side showed a more pronounced mean anteversion in the femur of 2.2° (p = 0.002) and the right side higher mean external rotation in the tibia of 2.8° (p < 0.001). Overall leg rotation showed 5.1° more mean external rotation on the right side (p < 0.001) with both methods. Absolute side-to-side whole leg rotation difference was 9.5°. Absolute differences between both methods were 3.3°. The variance was high. 23 femora were retroverted, 1 tibia internally rotated, and 9 legs were overall internally rotated. No variables differed between female and male subjects except for femoral version (right p = 0.003 and left p = 0.002). Correlation coefficients were high (rho 0.550-0.934, all p < 0.001). CONCLUSION: There is a significant prevalence of side-to-side asymmetry in femoro-tibial torsion. Although side-to-side differences are not extraordinary, comparative axial femoro-tibial rotation alignment should always be interpreted with caution. LEVEL OF EVIDENCE: Diagnostic, retrospective cohort study, level III.

Association between changes in knee load and effusion-synovitis: evidence of mechano-inflammation in knee osteoarthritis using high tibial osteotomy as a model.

OBJECTIVE: Although mechanically-induced inflammation is an appealing explanation linking different etiologic factors in osteoarthritis (OA), clinical research investigating changes in both biomechanics and joint inflammation is limited. The purpose of this study was to evaluate the association between change in surrogate measures of knee load and knee effusion-synovitis in patients with medial compartment knee OA undergoing high tibial osteotomy (HTO). METHODS: Thirty-six patients with medial compartment knee OA and varus alignment underwent 3D gait analysis and 3T magnetic resonance imaging (MRI) preoperatively and 1 year after medial opening wedge HTO. Primary outcome measures were the change in the external knee adduction moment impulse during walking and change in knee suprapatellar effusion-synovitis volume manually segmented on MRI by one blinded assessor. RESULTS: Mean (SD) knee adduction moment impulse [24.0 (6.5) Nm•s] and knee effusion-synovitis volume [8976.7 (8016.9) mm3] suggested substantial preoperative medial knee load and inflammation. 1-year postoperative changes in knee adduction moment impulse [-10.1 Nm•s (95%CI: -12.7, -7.4)], and knee effusion-synovitis volume [-1856 mm3 (95%CI: -3830, 117)] were positively correlated [r = 0.60 (95% CI 0.34, 0.78)]. Simple linear regression suggested a 448 mm3 (95%CI: 241, 656) reduction in knee effusion-synovitis volume per 1 Nm•s reduction in knee adduction moment impulse. Change in knee adduction moment impulse explained 36% (R2 = 0.36) of the variance of change in knee effusion-synovitis volume. CONCLUSIONS: Reduction in medial knee load is positively associated with reduction in knee inflammation after HTO, suggesting the phenomenon of mechano-inflammation in patients with knee OA.