The knee-spine syndrome. Association between lumbar lordosis and extension of the knee

Effect of inverse kinematic alignment total knee arthroplasty on coronal alignment of the ankle joint in patients with varus knee deformity

INTRODUCTION

Varus or valgus knee deformities influence ankle coronal alignments. The impact of Total Knee Arthroplasty (TKA) on ankle joint alignment has not been entirely illustrated. Inverse Kinematic Alignment (iKA) is a surgical philosophy that aims to restore soft tissue balance, function, and native anatomy within validated boundaries to restore restrictive native kinematics. Therefore, this study aimed to investigate the postoperative association of patient-specific alignment on the coronal alignment of the ankle in patients with varus knee deformity who underwent iKA TKA. We hypothesized that greater preoperative varus malalignments would correlate with significant postoperative ankle coronal alignment changes.

METHODS

This retrospective study of a prospective collected cohort assessed patients who underwent imageless navigation assisted robotic TKA using a single implant design for primary osteoarthritis between January 2022 and August 2023. Preoperative and postoperative full-length standing anteroposterior X-ray imaging was used to measure Hip-Knee-Ankle (HKA), Tibial Plafond Inclination (TPI), Talar inclination (TI), and Tibiotalar Tilt (TTT) angles. Patients were subsequently divided into groups of neutral varus) < 10°) and severe varus (≥ 10°) according to the preoperative HKA angle.

RESULTS

Significant changes in preoperative and postoperative HKA angles were found in the severe varus (14.5° vs. 6.4°, p < 0.001) group. Changes were also significant between preoperative and postoperative TPI and TI angles in the severe varus group; however, TTT did not reach statistical significance. Delta change from pre- to postoperative HKA was significantly higher for the severe varus group (8.1° vs. 0.8°, p < 0.019). Delta change of TPI, TI and TTT did not differ between groups.

CONCLUSION

Coronal knee alignment after TKA affects coronal alignment of the ankle. iKA technique in TKA for varus knee deformity preserves or minimizes substantial coronal alignment changes of the ankle joint. These findings may add to the benefits reported for patient specific alignment TKA techniques.

LEVEL OF EVIDENCE

III.

Preoperative Abnormal Posture Improves After Total Knee Arthroplasty: Knee-Hip-Spine Syndrome

BACKGROUND

Spinal, pelvic, and lower extremity alignment is crucial for maintaining a healthy body posture. However, with aging, this posture becomes challenging to maintain due to muscle weakness and skeletal degeneration. Osteoarthritis (OA) of the hip and knee can also lead to abnormal posture, known as hip-spine and knee-spine syndrome. Total knee arthroplasty (TKA) can help relieve pain and improve lower extremity alignment. This may also improve abnormal posture, such as in knee-hip-spine syndrome. However, the condition of the contralateral knee may affect this improvement. This study evaluated the effects of TKA on clinical outcomes and radiographic body posture.

METHODS

Patients scheduled for primary one-sided TKA were divided into two groups: the unilateral group comprised patients who had contralateral knee OA conditions. The bilateral group included patients who had prior contralateral TKA. Knee range of motion (ROM), the Knee Injury and Osteoarthritis Outcome Score (KOOS), radiographic lateral femorotibial angle (FTA), hip and knee flexion angles, and sagittal vertical axis (SVA) while standing were measured 24 months after TKA.

RESULTS

Both groups showed improved knee extension, KOOS, and radiographical FTA and hip and knee flexion angles 24 months after TKA. The SVA also improved 6 months after TKA in both groups and was maintained in the bilateral group, while it deteriorated again in the unilateral group 24 months after TKA.

CONCLUSION

A TKA can improve abnormal body posture due to knee OA as in knee-hip-spine syndrome. However, the condition of a contralateral knee can affect TKA outcomes.

Impact of the sagittal spinopelvic and coronal lower extremity alignments on clinical outcomes after medial unicompartmental knee arthroplasty

Introduction

We evaluated whether the clinical outcomes, including postoperative knee range of motion (ROM), after unicompartmental knee arthroplasty (UKA) were associated with the sagittal spinopelvic parameters and coronal alignment of the full lower extremity.

Methods

Forty-two patients (50 knees: six men, seven knees; 36 women, 43 knees) who underwent medial UKA between April 2015 and December 2022 were included. Preoperative radiographic examinations of the index for sagittal spinopelvic alignment included the sagittal vertical axis (SVA), lumbar lordosis, sacral slope (SS), pelvic tilt (PT), and pelvic incidence. The anteroposterior hip-knee-ankle angle (HKAA) was calculated. The relationship of clinical outcomes and the risk of knee flexion angle ≤125° and knee flexion contracture ≥10° 1-year post-UKA with radiographic parameters were evaluated.

Results

Preoperative HKA angle affected postoperative knee flexion angle ≤125° (p = 0.017, 95% confidence interval [CI]: 0.473-0.930) in logistic regression analysis. Patients with a knee flexion angle ≤125° had a higher preoperative HKAA (9.8 ± 3.0°), higher SVA (83.8 ± 37.0 mm), and lower SS (23.7 ± 9.0°) than those with a flexion angle >125° (preoperative HKAA: 6.6 ± 4.0°, SVA: 40.3 ± 46.5 mm, SS: 32.0 ± 6.3°) (p = 0.029, 0.012, and 0.004, respectively). PT related to postoperative knee flexion contracture ≥10° (p = 0.010, 95% CI: 0.770-0.965) in the logistic regression analysis. Patients with flexion contracture ≥10° had higher PT (35.0 ± 6.6°) and SVA (82.2 ± 40.5 mm) than those with flexion contracture <10° (PT, 19.3 ± 9.0°; SVA, 42.4 ± 46.5 mm) (p = 0.001 and 0.028, respectively). The postoperative clinical outcome was correlated with the postoperative knee flexion angle and SVA (p = 0.036 and 0.020, respectively).

Conclusions

The preoperative HKAA affected postoperative knee flexion angle, and the knee flexion contracture and clinical outcomes post-UKA were associated with PT and SVA, respectively. To predict outcomes for knee ROM and clinical scores after UKA, radiographic examination, including the sagittal spinopelvic parameters and the coronal view of the full lower extremity, is essential.

Impact of Hip and Knee Osteoarthritis on Full Body Sagittal Alignment and Compensation for Sagittal Spinal Deformity

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

To investigate the effect of lower extremity osteoarthritis on sagittal alignment and compensatory mechanisms in adult spinal deformity (ASD).

BACKGROUND

Spine, hip, and knee pathologies often overlap in ASD patients. Limited data exists on how lower extremity osteoarthritis impacts sagittal alignment and compensatory mechanisms in ASD.

PATIENTS AND METHODS

In total, 527 preoperative ASD patients with full body radiographs were included. Patients were grouped by Kellgren-Lawrence grade of bilateral hips and knees and stratified by quartile of T1-Pelvic Angle (T1PA) severity into low-, mid-, high-, and severe-T1PA. Full-body alignment and compensation were compared across quartiles. Regression analysis examined the incremental impact of hip and knee osteoarthritis severity on compensation.

RESULTS

The mean T1PA for low-, mid-, high-, and severe-T1PA groups was 7.3°, 19.5°, 27.8°, and 41.6°, respectively. Mid-T1PA patients with severe hip osteoarthritis had an increased sagittal vertical axis and global sagittal alignment ( P <0.001). Increasing hip osteoarthritis severity resulted in decreased pelvic tilt ( P =0.001) and sacrofemoral angle ( P <0.001), but increased knee flexion ( P =0.012). Regression analysis revealed that with increasing T1PA, pelvic tilt correlated inversely with hip osteoarthritis and positively with knee osteoarthritis ( r2 =0.812). Hip osteoarthritis decreased compensation through sacrofemoral angle (β-coefficient=-0.206). Knee and hip osteoarthritis contributed to greater knee flexion (β-coefficients=0.215, 0.101; respectively). For pelvic shift, only hip osteoarthritis significantly contributed to the model (β-coefficient=0.100).

CONCLUSIONS

For the same magnitude of spinal deformity, increased hip osteoarthritis severity was associated with worse truncal and full body alignment with posterior translation of the pelvis. Patients with severe hip and knee osteoarthritis exhibited decreased hip extension and pelvic tilt but increased knee flexion. This examines sagittal alignment and compensation in ASD patients with hip and knee arthritis and may help delineate whether hip and knee flexion is due to spinal deformity compensation or lower extremity osteoarthritis.

Knee flexion compensation in postoperative adult spinal deformity patients: implications for sagittal balance and clinical outcomes

PURPOSE

To determine whether maintaining good sagittal balance with significant knee flexion (KF) constitutes a suboptimal outcome after adult spinal deformity (ASD) correction.

METHODS

This single-center, single-surgeon retrospective study, assessed ASD patients who underwent posterior spinal fusion between 2014 and 2020. Inclusion criteria included meeting at least one of the following: PI-LL ≥ 25°, T1PA ≥ 20°, or CrSVA-H ≥ 2 cm. Those with lower-extremity contractures were excluded. Patients were classified into four groups based on their 6-week postoperative cranio-hip balance and KF angle, and followed for at least 2 years: Malaligned with Knee Flexion (MKF+) (CrSVA-H > 20 mm + KFA > 10), Malaligned without Knee Flexion (MKF-) (CrSVA-H > 20 mm + KFA < 10), Aligned without Knee Flexion (AKF-) (CrSVA-H < 20 mm + KFA < 10), and Aligned with Knee Flexion (AKF+) (CrSVA-H < 20 mm + KFA > 10). The primary outcomes of this study included one and two year reoperation rates. Secondy outcomes included clinical and patient reported outcomes.

RESULTS

263 patients (mean age 60.0 ± 0.9 years, 74.5% female, and mean Edmonton Frailty Score 3.3 ± 0.2) were included. 60.8% (160/263 patients) exhibited good sagittal alignment at 6-week postop without KF. Significant differences were observed in 1-year (p = 0.0482) and 2-year reoperation rates (p = 0.0374) across sub-cohorts, with the lowest and highest rates in the AKF- cohort (5%, n = 8) and MKF + cohort (16.7%, n = 4), respectively. Multivariable Cox regression demonstrated the AKF- cohort exhibited significantly better reoperation outcomes compared to other groups: AKF + (HR: 5.24, p = 0.025), MKF + (HR: 31.7, p < 0.0001), and MKF- (HR: 11.8, p < 0.0001).

CONCLUSION

Our findings demonstrate that patients relying on knee flexion compensation in the early postoperative period have inferior outcomes compared to those achieving sagittal balance without knee flexion. When compared to malaligned patients, those with CrSVA-H < 20 mm and KFA > 10 degrees experience fewer early reoperations but similar delayed reoperation rates. This insight emphasizes the importance of considering knee compensation perioperatively when managing sagittal imbalance in clinical practice.

Novel subtype of coxitis knee associated with acetabular dysplasia of the hip: a case series

BACKGROUND

Multiple joint arthritis patterns require a comprehensive understanding to optimize patient management. This study aimed to present a patient cohort that deviated from known definitions of coxitis knee (CK), identifying and characterizing this atypical group.

METHODS

Patients undergoing both total hip arthroplasty and total knee arthroplasty between January 2008 and December 2018 were retrospectively reviewed. The patients were classified into a typical coxitis knee group (classic, long leg arthropathy, and windswept deformity) and an atypical coxitis knee group. Leg-length discrepancy, body mass index (BMI), and radiographic parameters of the groups were compared and analyzed.

RESULTS

A total of 31 patients were allocated to the typical coxitis knee group (n = 10), and atypical coxitis knee group (n = 21). In the atypical group, 27 hips were involved, of which 21 had acetabular dysplasia, 5 exhibited subchondral insufficiency fracture-like changes, and only 1 had classic osteoarthritis. Among the 27 knees undergoing total knee arthroplasty, 26 showed varus alignment, 1 was within the normal range, and none was valgus. Acetabular dysplasia involved ipsilateral (n = 1), contralateral (n = 14), and bilateral (n = 6) hips, showing atypical coxitis knee. Patients with acetabular dysplasia were more likely to exhibit atypical CK.

CONCLUSION

Most patients in the cohort displayed acetabular dysplasia and contralateral varus knees, constituting a pattern referred to as acetabular dysplasia-associated gonarthritis. Identifying this novel subtype may have important clinical implications for regions with high risk factors, where acetabular dysplasia and constitutional genu varum are prevalent.

Evaluation of lumbar and hip movement characterization and muscle activities during gait in patients with knee osteoarthritis

Patients with knee osteoarthritis (KOA) might have gait deviations, but few previous studies have discussed gait compensatory movements of the proximal and distal parts of muscle groups related to KOA. The study aimed to measure lumbar and hip movements during gait test and collect muscle activities of the lower extremities. Thirty-four participants with KOA and 28 healthy participants aged over 50 years were recruited for this study. Lumbar and hip motions during walking test were measured using inertial measurement units. Four muscle groups of the lower extremity (erector spinae, gluteus maximus, quadriceps muscle, and gastrocnemius) activities in gait were collected using surface EMGs. KOA patients used an 2.12∘anterior inclined lumbar spine (p = 0.007) and 22.94∘ flexed hip (p = 0.001) in gait compared to healthy participants. The KOA patients had a small hip movement range 30.19∘(p = 0.001) and a higher asymmetric stance time ratio 0.39 (p = 0.006). Patients with KOA showed decreased erector spinae and gluteus maximus muscle activation and increased activation of the quadriceps and gastrocnemius muscles during gait. In conclusion, patients with KOA used a hyperlordotic lumbar and hip flexed strategy, which overactivates distal extensor muscles through the whole gait and might cause overstress on the lower extremity joints.

Asymmetric Flexion Contracture is Associated With Leg Length Inequality in Patients With Knee Osteoarthritis: Data From the Osteoarthritis Initiative

OBJECTIVE

To evaluate whether knee flexion contracture (FC) was associated with leg length inequality (LLI) and/or morbidity in knee osteoarthritis (OA).

DESIGN

We accessed 2 databases: (1) the Osteoarthritis Initiative (OAI) cohort, including participants with, or at-risk of OA, and (2) the Ottawa Knee Osteoarthritis cross-sectional database (OKOA), including participants with primary advanced knee OA. Both included demographics, radiographic data, knee range of motion, leg length, pain, and function scales.

SETTING

Tertiary care academic rheumatology and orthopedic clinics.

PARTICIPANTS

Patients with or at-risk of primary OA. We included 881 OAI and 72 OKOA participants (N=953).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

The primary outcome tested the association between the difference in knee extensions of the OA and contralateral knees (the knee extension difference, or KExD) and LLI. This was evaluated using bivariate regression, followed by a multivariable linear regression model.

RESULTS

OAI participants had less severe knee OA [Kellgren and Lawrence (KL) score 1.9±1.3] vs OKOA (KL score 3.4±0.6). The KExD correlated with LLI for both databases (OAI: R=0.167; P≤.001; OKOA: R=0.339; P=.004). Multivariable regression showed an effect of KExD on LLI in both databases (OAI: β=0.37[0.18,0.57]; P<.001, OKOA: β=0.73[0.20,1.26]; P=.007). When broken down by subgroup, the OAI moderate-severe OA group showed a significant effect of KExD on LLI (β=0.60 [0.34,0.85]; P<.001).

CONCLUSIONS

OA-related loss of knee extension was associated with LLI for those with moderate-severe OA. Because LLI correlates with worse knee OA symptoms, discovering an FC should cue clinicians to evaluate for LLI, an easily-treatable finding that may help reduce OA-associated morbidity for those approaching the need for arthroplasty.

Assessing knee joint biomechanics and trunk posture according to medial osteoarthritis severity

During progression of knee osteoarthritis (OA), gait biomechanics changes three-dimensionally; however, its characteristics and trunk posture according to OA severity remain unknown. The present study investigated three-dimensional knee joint biomechanics and trunk posture according to knee OA severity. Overall, 75 patients (93 knees) with medial knee OA [Kellgren-Lawrence grade ≥ 2, grade 2: 20 patients with 24 knees (mean 60.0 years old); grade 3: 25 with 28 knees (mean 62.0 years old); grade 4: 30 with 41 knees (mean 67.9 years old)] and 14 healthy controls (23 knees, mean 63.6 years old) underwent gait analysis using an optical motion capture system and point cluster technique. In grade 2 knee OA, the relative contribution of the knee adduction moment (KAM) increased significantly (P < 0.05), and that of the knee flexion moment decreased (P < 0.05) prior to significant progression of varus knee deformity. Grade 3 knee OA showed significant exacerbation of varus knee deformity (P < 0.01) and KAM increase (P < 0.001). The maximum knee extension angle decreased (P < 0.05) and trunk flexion increased during gait in grade 4 knee OA (P < 0.001). Our study clarified the kinematics and kinetics of medial knee OA with trunk flexion according to severity. Kinetic conversion occurred in grade 2 knees prior to progression of varus deformities, knee flexion contractures, and sagittal imbalance during gait in patients with severe knee OA.

Does total knee arthroplasty affect pelvic movements? A prospective comparative study

OBJECTIVE

Pathology in any segment of the spine-pelvis-lower extremity may impair the global postural balance, leading to compensatory alterations in other parts. The aim of this study was to compare the pelvic movements of patients suffering from knee osteoarthritis with patients who underwent total knee arthroplasty and healthy controls.

METHODS

This study was performed at the Department of Orthopedics and Traumatology Clinic of a Cankiri State Hospital between April 2021 and February 2022. This study included 84 participants. Of them, 31 patients who underwent total knee arthroplasty between 2018 and 2020 years were selected as the total knee arthroplasty group, while 28 patients with knee osteoarthritis were selected as the knee osteoarthritis group. In the control group, there were 25 healthy individuals. Exclusion criteria from the study included any kind of neurological disease, an inability to walk a distance of 100 m unassisted, or a history of surgery to the lower limb. Pelvic movements (i.e., tilt, rotation, and obliquity) and gait parameters (i.e., "gait velocity," "cadence," and "stride length") were assessed using a wireless tri-axial accelerometer.

RESULTS

Total knee arthroplasty and control groups had decreased minimum anterior tilt of the pelvis, decreased maximum anterior tilt, and decreased oblique range of the pelvis compared with the knee osteoarthritis group. In comparison with the control group, gait velocity and length of stride during gait were remarkably lower in both knee osteoarthritis and total knee arthroplasty groups.

CONCLUSION

In this study, total knee arthroplasty was found to affect pelvic movements. It was thought that total knee arthroplasty changed these variables, probably owing to the frontal and sagittal plane alignment correction through surgery.

Differences in Involvement of Whole-Body Compensatory Alignment for Decompensated Spinopelvic Sagittal Balance

BACKGROUND

The aim of this study was to investigate the differences in the involvement of whole-body compensatory alignment in different conditions of spinopelvic sagittal balance (compensated/decompensated).

METHODS

We enrolled 330 individuals who underwent medical checkups and divided them according to sagittal vertical axis (SVA): for the compensated group, this was <4 cm, (group C) and for the decompensated group, it was ≥4 cm, (group D). The correlation between the lack of ideal lumbar lordosis (iLL), which was calculated by using the Schwab formula, and the compensatory radiographic parameters in each group was analyzed. The threshold value of knee flexion (KF) angle, which indicated spinopelvic sagittal imbalance (SVA ≥ 4), was determined by a ROC-curve analysis.

RESULTS

The correlation analysis of the lack of iLL and each compensatory parameter showed a strong correlation for pelvic tilt (PT) (r = -0.723), and a weak correlation for thoracic kyphosis (TK) (r = 275) in Group C. In Group D, the correlations were strong for PT (r = -0.796), and moderate for TK (r = 0.462) and KF (r = -0.415). The optimal cutoff value for the KF angle was determined to be 8.4 degrees (sensitivity 89%, specificity 46%).

CONCLUSIONS

The present study shows differences between compensated/decompensated spinopelvic sagittal balance in the correlation strength between lack of iLL and whole-body compensatory parameters.

Relationship between spinal imbalance and knee osteoarthritis by using full-body EOS

BACKGROUND

Orthostatic state is maintained by harmonizing the spine, pelvis and lower extremities. In the past few decades, several studies have demonstrated the associations between spinal imbalance and generalized osteoarthritis. The compensatory mechanisms of pelvis translation and knee flexion, however, have not been fully assessed.

METHODS

A total of 213 volunteers, over 40 years of age, were recruited. Radiological measurements were performed by EOS imaging system. Pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), sagittal vertical axis (SVA), global tilt (GT), hip-knee-angle (HKA), knee flexion angle (KFA), lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA) were measured. On the basis of SRS-Schwab, the subjects were classified into decompensated group (PI-LL > 20°), compensated group(10° ≤ PI-LL ≤ 20°), and normal group (PI-LL < 10°). Differences in radiographic parameters among groups were evaluated. Data of Knee Society Score (KSS) and Oswestry Disability Index (ODI) score were collected via questionnaires.

RESULTS

Decompensated group showed larger pelvic parameters (PT) and low extremity parameters (LDFA, MPTA, HKA and KFA) than normal group (P < 0.05). Pelvic parameter was larger in the compensated group (median = 31°) compared to the normal group (median = 17°) (P < 0.05). There was no difference in low extremity parameters between the compensated and normal groups. At the sagittal plane, the radiological parameters of spine were greater in subjects with patellofemoral joint pain (PFP) than without PFP (P = 0.058). Higher PI-LL values were observed in women (P < 0.05).

CONCLUSIONS

A correlation between sagittal spinal imbalance and knee joint angles was recognized. The progression of knee and low back pain was associated with the severity of sagittal spinal imbalance. Pelvic retroversion was considered to be the probable compensatory mechanism.

Total knee arthroplasty in patients with lumbar spinal fusion leads to significant changes in pelvic tilt and sacral slope

BACKGROUND

The knee-hip-spine syndrome has been well elucidated in the literature in recent years. The aim of this study was to evaluate the effect of total knee arthroplasty (TKA) on spinopelvic sagittal alignment in patients with and without pre-TKA lumber spinal fusion.

METHODS

This is a retrospective cohort study of 113 patients who underwent TKA for primary osteoarthritis. Patients were stratified into the following three groups: (1) patients who had pre-TKA spinal fusion (SF, n = 19), (2) patients who had no spinal fusion but experienced pre-TKA flexion contracture (FC, n = 20), and (3) patients without flexion contracture or spinal fusion before TKA (no SF/FC, n = 74). Spinopelvic sagittal alignment parameters, including pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), and plumb line-sacrum distance (SVA) were measured preoperatively and 3 months postoperatively on lateral standing full-body low-dose images.

RESULTS

TKA resulted in significant pre- to postoperative changes in pelvic tilt (average ∆ PT = - 8.6°, p = 0.018) and sacral slope (average ∆ SS = 8.6°, p = 0.037) in the spinal fusion (SF) group. Non-significant changes in spinopelvic sagittal alignment parameters (PT, SS, LL, TK, SVA) were noted postoperatively in all patients in the FC and the no SF/FC groups.

CONCLUSIONS

TKA can lead to meaningful changes in spinopelvic alignment in patients with prior lumbar fusion compared to those without spinal fusion. Patients with spinal fusion who are candidates for both hip and knee replacements should consider undergoing TKA first since changes in spinopelvic sagittal alignment can increase the risk of future complications.

LEVEL III EVIDENCE

Retrospective Cohort Study.

How Back Pain Affects Patient Satisfaction After Primary Total Knee Arthroplasty

BACKGROUND

Although back pain (BP) has been shown to be a predictor of dissatisfaction after total knee arthroplasty (TKA) in some reports, these studies did not use a scale to quantify the degree of pain. The purpose of this study was to quantify the effect of BP intensity on patient satisfaction reported at 1 year after TKA.

METHODS

A multicenter prospective cohort was taken in which 9,057 patients undergoing primary unilateral TKA were enrolled in FORCE-TJR and demographic and clinical data were collected. Back pain (BP) intensity was assessed using the Oswestry back disability index (ODI) pain intensity questionnaire. Patients were classified into 4 categories based on the severity of BP. Patient-reported outcomes (PROs) were collected preoperatively and postoperatively after 1 year including the Knee injury and Osteoarthritis Outcome Score (KOOS) (total score, pain, Activities of Daily Living (ADL), and Quality of Life (QOL), Short-Form health survey 36-item (SF-36) Physical Component Score (PCS), and Mental Component Score (MCS)). We used a validated 5-point Likert satisfaction scale. Univariate analyses of the difference between the satisfied and dissatisfied patients' groups was performed. Multivariate logistic regression models with 95% confidence interval (CI) were used to quantify the effect of BP intensity on patient dissatisfaction at 1 year. Receiver operating characteristic (ROC) analyses were performed with measurement of area under curve (AUC).

RESULTS

At 1 year, a total of 1,657 TKA patients (18.3%) were dissatisfied. A total of 4,765 patients (52.6%) reported back pain at the time of surgery, including mild BP in 2,264 patients (24.9%), moderate BP in 1,844 patients (20.3%), and severe BP in 657 patients (7.2%). Severe back pain was significantly associated with patient dissatisfaction at 1 year after TKA (P = .0006). The multivariate regressions showed that patients who had severe BP were 1.6 times more likely to be dissatisfied when compared to patients who had no BP [odds ratio (OR) 1.63; 95% confidence interval (CI) (1.23-2.16), P = .0006]. While patients who had mild BP [OR 0.98; 95% CI (0.82-1.17), P = .87] or moderate BP [OR 0.97; 95% CI (0.80-1.18), P = .78] were not associated with an increased likelihood of dissatisfaction. Other predictive variables for dissatisfaction, include age [OR for younger patients <65 years versus older patients ≥65 years, 0.74; 95% CI (0.59-0.92)], educational level [OR for post high school versus less, 0.83; 95% CI (0.71, 0.97)], smoking [OR for nonsmoker versus current smoker, 0.63; 95% CI (0.45, 0.87)], and Charlson comorbidity index [OR for CCI ≥2 versus 0, 1.25; 95% CI (1.05, 1.49)].

CONCLUSION

Increased BP intensity was associated with increased risk of dissatisfaction 1 year after TKA. Only patients who had severe BP were 1.6 times more likely to be dissatisfied. The data presented here can help to improve shared decision-making and patient counseling before surgery. Surgeons should consider a spine evaluation in patients who have severe BP prior to TKA.

Biomechanical and clinical relationships between lower back pain and knee osteoarthritis: a systematic review

BACKGROUND

Osteoarthritis (OA) and lower back pain (LBP) are most common health problems which lead to pain and disability. This study aimed to systematically review the evidence to find any relationship between knee osteoarthritis (KOA) and LBP or any potential causation.

METHODS

The databases of Scopus, MEDLINE, and Embase were searched from inception to 01 October 2022. Any study published in English assessing live humans over 18 years with KOA and LBP was eligible to be included. Studies were independently screened by two researchers. Data of the included studies were extracted based on the participants, outcomes related to knee and lumbar spine, reported association or causation between LBP and KOA, and study design. Data were narratively analyzed and presented as graphs and table. Methodology quality was assessed.

RESULTS

Of 9953 titles and abstracts, duplicates were removed, and 7552 were screened. Altogether, 88 full texts were screened, and 13 were eligible for the final inclusion. There were some biomechanical and clinical causations were observed for the concurrent presence of LBP and KOA. Biomechanically, high pelvic incidence is a risk factor for development of spondylolisthesis and KOA. Clinically, knee pain intensity was higher in KOA when presents with LBP. Less than 20% of studies have justified their sample size during the quality assessment.

DISCUSSION

Development and progression of KOA in patients with degenerative spondylolisthesis may be induced by significantly greater mismatches of lumbo-pelvic sagittal alignment. Elderly patients with degenerative lumbar spondylolisthesis and severe KOA reported a different pelvic morphology, increased sagittal malalignment with a lack of lumbar lordosis due to double-level listhesis, and greater knee flexion contracture than in patients with no to mild and moderate KOA. People with concurrent LBP and KOA have reported poor function with more disability. Both LBP and lumbar kyphosis indicate functional disability and knee symptoms in patients with KOA.

CONCLUSIONS

Different biomechanical and clinical causations were revealed for the concurrent existence of KOA and LBP. Therefore, careful assessment of both back and knee joints should be considered when treating KOA and vice versa.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022238571.

Spondylolisthesis and mismatch deformity affect outcomes after total knee arthroplasty

BACKGROUND

Little published data currently exist regarding the potential relationships between spondylolisthesis, mismatch deformity, and clinical outcomes following total knee arthroplasty (TKA). We hypothesize that preexisting spondylolisthesis will result in decreased functional outcomes after TKA.

METHODS

This retrospective cohort comparison of 933 TKAs was performed between January 2017 and 2020. TKAs were excluded if they were not performed for primary osteoarthritis (OA) or if preoperative lumbar radiographs were unavailable/inadequate to measure the degree of spondylolisthesis. Ninety-five TKAs were subsequently available for inclusion and divided into two groups: those with spondylolisthesis and those without. Within the spondylolisthesis cohort, pelvic incidence (PI) and lumbar lordosis (LL) were calculated on lateral radiographs to determine the difference (PI-LL). Radiographs with PI-LL > 10° were then categorized as having mismatch deformity (MD). The following clinical outcomes were compared between the groups: need for manipulation under anesthesia (MUA), total postoperative arc of motion (AOM) both pre-MUA or post-MUA/revision, incidence of flexion contracture, and a need for later revision.

RESULTS

Forty-nine TKAs met the spondylolisthesis criteria, while 44 did not have spondylolisthesis. There were no significant differences in gender, body mass index, preoperative knee range of motion (ROM), preoperative AOM, or opiate use between the groups. TKAs with spondylolisthesis and concomitant MD were more likely to have MUA (p = 0.016), ROM < 0-120 (p < 0.014), and a decreased AOM (p < 0.02) without interventions.

CONCLUSION

Preexisting spondylolisthesis by itself may not have adverse effect clinical results following TKA. However, spondylolisthesis increases the likelihood of developing MD. In those with both spondylolisthesis and concomitant mismatch deformities, patients had statistically and clinically significantly decreased in postoperative ROM/AOM and increased need for MUA. Surgeons should consider clinical/radiographic assessments of patients with chronic back pain who present for total joint arthroplasty.

LEVEL OF EVIDENCE

Level 3.

The "In-Parallel" Technique for Awake, Bilateral Simultaneous Minimally Invasive Transforaminal Lumbar Interbody Fusion and Multilevel Lumbar Decompression

BACKGROUND

Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) and MIS lumbar decompression have been successfully undertaken in the absence of general anesthesia in well-selected patients. By leveraging spinal anesthesia, surgeons may safely conduct surgeries on one- or two-level lumbar pathology. However, surgeries on more extensive pathology have not yet been described, because of concerns about the duration of efficacy of spinal anesthetic in the awake patient.

OBJECTIVE

To report the use of a novel awake technique for "in parallel," simultaneous lumbar spinal surgery on three-segment pathology.

METHODS

We describe concurrent performance of a dual microscopic, navigated MIS TLIF and MIS two-level decompression, using a combination of liposomal bupivacaine erector spinae block in conjunction with a spinal anesthetic.

RESULTS

We show that a left-sided, two-level MIS tubular microscopic decompression combined with a concurrent right-sided, transfacet MIS TLIF via a tubular microscopic approach was well tolerated in an 87-year-old patient with multilevel lumbar stenosis with a mobile spondylolisthesis.

CONCLUSION

We provide the first description of a dual-surgeon approach for minimally invasive spine surgery. This "in-parallel" technique-reliant on 2, independent spine surgeons-may aid in the performance of surgeries previously considered too extensive, given the time constraints of regional anesthesia and can be successfully applied to patients who otherwise may not be candidates for general anesthesia.

Sagittal spinal alignment and mobility and their relation to physical function in women with and without mild-to-moderate knee osteoarthritis

Recent studies suggest that patients with lower extremity osteoarthritis may have altered spinal posture. We aimed to investigate age and body mass index-adjusted sagittal spinal alignment and mobility and their relation to physical function in women over 40 years of age with and without mild-to-moderate knee osteoarthritis (KOA). Thirty-two women with unilateral mild-to-moderate KOA and thirty-two asymptomatic women were included. A skin-surface device was used to assess sagittal alignment and mobility of the thoracic, lumbar, and sacral regions and trunk inclination angle. Physical function was assessed using the Timed Up and Go test. Analysis of covariance was used to compare groups and correlation coefficients were calculated separately for two groups. Women with KOA had higher thoracic kyphosis and lumbar lordosis compared to asymptomatic women (p < 0.05). The mean differences were 6.60 (%95 Confidence Interval 1.38;11.82) and -5.63 (-10.06;-1.20) for thoracic kyphosis and lumbar lordosis, respectively. Physical function score was moderately correlated with trunk inclination angle and lumbar, sacral, and trunk inclination mobility in asymptomatic women (r = 0.400, -0.504, -0.602, and -0.681, p < 0.05), but a significant correlation was not found in women with KOA (p > 0.05). In conclusion, women with KOA had altered spinal alignment. Spinal alignment and mobility were related to physical function in asymptomatic women over 40 years of age. Addressing sagittal spinal alignment in the clinical management of KOA may provide valuable data, especially for preventing possible spinal disorders.

Lumbar Spine Sagittal Mismatch Deformity Negatively Affects Total Knee Arthroplasty Outcomes

There is currently a paucity of data regarding the potential relationships between preexisting spinal deformity and clinical outcomes following total knee arthroplasty (TKA). We sought to expand upon this deficit. We hypothesize that lumbar sagittal mismatch deformity (MD) will correlate with a decrease in functional outcomes after TKA. This retrospective cohort comparison of 933 TKAs was performed between January 2017 and 2020. TKAs were excluded if they were not performed for primary osteoarthritis (OA) or if preoperative lumbar radiographs were unavailable/inadequate to measure sagittal parameters of interest: pelvic incidence, sacral slope, pelvic tilt, lumbar lordosis, and deformity mismatch. Ninety-four TKAs were subsequently available for inclusion and divided into two groups: those with MD as defined by |PI-LL| > 10 degrees and those without MD. The following clinical outcomes were compared between the groups: total postoperative arc of motion (AOM), incidence of flexion contracture, and need for manipulation under anesthesia (MUA). In total, 53 TKAs met the MD criteria, while 41 did not have MD. There were no significant differences in demographics, body mass index, preoperative knee range of motion (ROM), preoperative AOM, or opiate use between the groups. TKAs with MD were more likely to have MUA (p = 0.026), ROM <0 to 120 (p < 0.001), a decreased AOM by 16 degrees (p < 0.001), and a flexion contracture postoperatively (p = 0.01). Preexisting MD may adversely affect clinical results following TKA. Statistically and clinically significant decreases in postoperative ROM/AOM, increased likelihood of flexion contracture, and increased need for MUA were all noted in those with MD. This is a Level 3 study.

Knee Extension Is Related to the Posteriorly Deviated Gravity Line to the Pelvis in Young Adults: Radiographic Analysis Using Low-Dose Biplanar X-ray

PURPOSE

We sought to compare the radiographic parameters concerning the sagittal alignment of the standing whole-body skeletons between the knee extension group and control group using the low-dose biplanar X-ray system in a young adult population without knee pain, and to investigate the associated variables for the sagittal knee angle (sagKA) among the radiographic parameters of global sagittal alignment.

MATERIALS AND METHODS

We reviewed whole-body standing sagittal radiographs of 124 young adults taken from December 2018 to May 2020 in a single institution. We compared the radiographic parameters concerning the lower extremity sagittal alignment and global sagittal alignment between the knee extension group and control group. The factors correlated with sagKA were evaluated using multiple linear regression analysis.

RESULTS

The sagittal vertical axis (SVA), the horizontal offset between the gravity line (GL) and the posterior edge of S1 endplate (GL-S), and the horizontal offset between the GL and the hip center (GL-H) were -11.6±21.3 mm, 5.1±23.8 mm, and -25.1±27.1 mm in the knee extension group, respectively, which were significantly smaller than those in the control group. The C7 plumb line (C7PL) and GL were deviated posterior to the sacrum and the hip center in the knee extension group, with the mean sagKA of -5.6° in young adults.

CONCLUSION

The GL-H using GL, not the SVA using C7PL, was a significant radiographic factor associated with the sagKA.

Effect of Unilateral Knee Extension Restriction on the Lumbar Region during Gait

Unilateral knee extension restriction might change trunk alignment and increase mechanical load on the lumbar region during walking. We aimed to clarify lumbar region mechanical load during walking with restricted knee extension using a musculoskeletal model simulation. Seventeen healthy adult males were enrolled in this study. Participants walked 10 m at a comfortable velocity with and without restricted right knee extension of 15° and 30° using a knee brace. L4-5 joint moment, joint reaction force, and muscle forces around the lumbar region during walking were calculated for each condition. Peaks of kinetic data were compared among three gait conditions during 0%-30% and 50%-80% of the right gait cycle. Lumbar extension moment at early stance of the bilateral lower limbs was significantly increased in the 30° restricted condition (p ≤ 0.021). Muscle force of the multifidus showed peaks at stance phase of the contralateral side during walking, and the erector spinae showed force peaks at early stance of the bilateral lower limb. Muscle force of the multifidus and erector spinae increased with increasing degree of knee flexion (p ≤ 0.010), with a large effect size (η ² = 0.273-0.486). The joint force acting on L4-5 showed two peaks at early stance of the bilateral lower limbs during the walking cycle. The anterior and vertical joint force on L4-5 increased by 14.2%-36.5% and 10.0%-23.0% in walking with restricted knee extension, respectively (p ≤ 0.010), with a large effect size (η ² = 0.149-0.425). Restricted knee joint extension changed trunk alignment and increased the muscle force and the vertical and anterior joint force on the L4-5 joint during walking; this tendency became more obvious with increased restriction angle. Our results provide important information for therapists engaged in the rehabilitation of patients with knee contracture.

Effect of osteoarthritic knee flexion deformity correction by total knee arthroplasty on sagittal spinopelvic alignment in Indian population

BACKGROUND

Sagittal alignment of the spine, pelvis, and lower extremities is essential for maintaining a stable and efficient posture and ambulation. Imbalance in any element can result in compensatory changes in the other elements. Knee flexion is a compensatory mechanism for spinopelvic sagittal alignment and is markedly affected in severe knee osteoarthritis (OA). The correction of knee flexion deformity (KFD) by total knee arthroplasty (TKA) can lead to complementary changes in the sagittal spinopelvic parameters (SSPs).

AIM

To determine the SSP changes in patients with knee OA, with or without KFD undergoing TKA.

METHODS

The study was conducted in 32 patients who underwent TKA. A neutral standing whole-spine lateral radiograph was performed before surgery and 3 mo after surgery in these patients. Subjects were divided into two groups (Group 1 obtained > 10° corrections in KFD; group B obtained < 10° correction). The pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), and sagittal vertical axis (SVA) were measured.

RESULTS

The median of change in PT, PI, SS, LL, and SVA was 0.20 mm, 1.00 mm, 2.20 mm, −0.40 mm, and 6.8 mm, respectively. The difference in the change in SSPs between the two groups was statistically non-significant.

CONCLUSION

SSPs, such as PI, PT, SS, LL, and SVA, do not change significantly following TKA in end-stage knee OA despite a significant correction (> 10°) in KFD.

The Influence of Knee Osteoarthritis on Spinopelvic Alignment and Global Sagittal Balance

Osteoarthritis (OA) of the knee is thought to lead to a loss of lumbar lordosis (LL) as a compensation for knee flexion contracture. Changes in sagittal alignment are not limited to the lumbar spine and involve a complex interplay of alignment of the hip, pelvis, and spine. While spine-hip interactions have been previously explored, the influence of knee OA sagittal alignment parameters on spinopelvic alignment and global sagittal balance remains unexplored. Standing radiological examination using EOS biplanar radiography was examined in 108 patients with knee OA. Whole-body sagittal alignment parameters (thoracic kyphosis, LL, pelvic incidence, pelvic tilt [PT], femoropelvic angle [FPA], femoral tilt angle [FTA], tibial tilt angle, and knee flexion angle [KFA]) and global balance parameters (sagittal vertical axis [SVA] and odontoid hip axis [OD-HA] angle) were measured three dimensionally (3D). The correlation coefficients among all parameters were assessed. A multiple stepwise linear regression model was built to investigate the direct association between SVA or OD-HA angle (dependent variables) and sagittal alignment parameters and demographic data (independent variables). Significant correlations between KFA, FPA, FTA, SVA, and OD-HA angle were found. FTA was correlated with LL and FPA. The FTA was the most influential predictor of both global sagittal balance parameters (p < 0.001). Knee OA leads to changes in global sagittal balance with effects at the hip, knee, pelvis, and spine. FTA (forward flexion of the femur vs. the vertical plane) is the largest driver of global sagittal plane balance in patients with knee OA.

Effect of Total Knee Arthroplasty on Coronal Alignment of the Ankle Joint

BACKGROUND

The effect of total knee arthroplasty (TKA) on the ankle joint is not entirely clear. The purpose of this study is to assess postoperative changes in the coronal alignment of the ankle joint in patients undergoing TKA for various degrees of knee deformity.

METHODS

This retrospective study included 107 patients who had undergone TKA for primary osteoarthritis. In all cases, preoperative coronal alignment deformity of the knee was corrected in an attempt to restore the native mechanical axis of the knee. Patients were stratified into 3 groups according to the degree of knee coronal alignment correction achieved intraoperatively: group 1 (<10° varus/valgus correction, n = 60), group 2 (≥10° varus correction, n = 30), and group 3 (≥10° valgus correction, n = 17). Knee/ankle alignment angles were measured on full-length, standing anteroposterior imaging preoperatively and postoperatively and included the following: hip-knee-ankle angle, tibial plafond inclination (TPI), talar inclination (TI), and tibiotalar tilt angle.

RESULTS

Significant changes in ankle alignment, specifically with regard to TPI (9.5° ± 6.9°, P < .01) and TI (8.8° ± 8.8°, P = .03) were noted in the ≥10° valgus correction group compared to the other 2 groups. Regardless of the degree of knee deformity correction, TKA did not lead to significant changes in the tibiotalar tilt angle.

CONCLUSION

A correction of ≥10° in a genu valgum deformity can affect ankle joint alignment, leading to alterations in TPI and TI. These findings need to be taken into consideration in assessing candidates for TKA as a possible cause of postoperative ankle pain.

Higher Pelvic Incidence Was Associated with a Higher Risk of Sagittal Malposition of Femoral Component and Poor Outcomes of Primary Total Knee Arthroplasty: A Retrospective Cohort Analysis

Spine-pelvis-lower extremity sagittal alignment is regarded as a global sagittal balance. Currently, there are few studies evaluating the pelvic and femoral sagittal alignment during total knee arthroplasty (TKA). This retrospective study aims to elucidate how pelvic and femoral sagittal alignment affect clinical outcomes of primary TKA for osteoarthritis (OA) and determine the proper range of femoral sagittal alignment. Patient-reported outcome measures (PROMs), including the Knee Society Score (KSS), Western Ontario and McMaster Universities (WOMAC), and patient satisfaction scores, and clinician-reported outcomes (CROs), including range of motion (ROM) and pelvic and femoral sagittal parameters, of 67 cases were evaluated (89 knees) before and 1 year after TKA. The angle between the distal femur anterior cortex line and flange of the femoral component (FC) was defined as the α angle. Correlations between the α angle and PROM and CRO were investigated using multivariate and secondary regression analyses. Patients were further divided into four cohorts (A, B, C, and D) according to the α angle, and comparisons of their postoperative PROM and ROM scores were performed. Postoperative PROM and ROM scores improved significantly compared with the preoperative scores (p < 0.01). Only the α angle was significantly associated with postoperative knee extension among all PROM and CRO indexes (p = 0.001). Secondary regression demonstrated a convex upward function, and the scores were the highest at α angles of 0.57, 0.96, and -1.42 degrees for postoperative KSS, satisfaction, and range of knee extension, respectively (p < 0.01). However, the concave upward degree was the lowest at an α angle of 0.33 degrees for pelvic incidence (p < 0.001). Bonferroni's paired comparisons indicated that postoperative KSS and satisfaction of the cohort B (0 degrees ≤ α angle ≤ 3 degrees) were better than those of other cohorts (p < 0.0125). The results indicate that surgeons should pay more attention to the sagittal alignment of FC in patients with increased pelvic incidence, the distal femoral anterior cortex is recommended as an anatomic landmark, and 0 to 3 degrees might be "safe zones" of the sagittal flexion of FC in TKA. This study reflects the level of evidence III.

Computational Wear Prediction of TKR with Flatback Deformity during Gait

Loss of lumbar lordosis in flatback patients leads to changes in the walking mechanism like knee flexion. Such variations in flatback patients are predicted to alter the characteristics of total knee replacement (TKR) contact, so their TKR will show different wear characteristics with a normal gait. However, the relevant study is limited to predicting the wear depth of TKR for normal gait mechanisms or collecting and analyzing kinematic data on flatback gait mechanisms. The objective of this study was to compare wear in TKR of flatback patients with people without flatback syndrome. The main difference between the normal gait mechanism and the flat back gait mechanism is the knee flexion remain section and the tendency to change the vertical force acting on the knee. Thus, in this paper, A finite element-based computational wear simulation for the gait cycle using kinematic data for normal gait and flat gait were performed, and substituting the derived contact pressure and slip distance into the Archard formula, a proven wear model, wear depth was predicted. The FE analysis results show that the wear volume in flatback patients is greater. The results obtained can provide guidance on the TKR design to minimize wear on the knee implant for flatback patients.

Both arthroscopic and open posterior knee capsulotomy are effective in terms of extension recovery and functional improvement-systematic review

PURPOSE

To assess the recovery of extension and improvement in functional scores after an arthroscopic or open posterior knee capsulotomy in the setting of an extension deficit.

METHODS

A systematic search of articles published between 1980 and 2020 was performed in the MEDLINE/PubMed database, EMBASE/Ovid database and Web of Science database. The inclusion criteria consisted of patients with primary extension deficits > 5° who underwent an arthroscopic or open posterior knee capsulotomy. The assessed outcomes were preoperative and postoperative range of motion and functional outcome scores. Randomized controlled trials, cohort studies and case series with a follow-up longer than 6 months were included. The risk of bias was assessed using the Joanna Briggs Institute critical appraisal tool for case series. The certainty of evidence was assessed using the GRADE approach.

RESULTS

Of 226 records identified through database searching, 7 studies were included in the final analysis. The outcomes of 107 patients with a mean age of 34.1 (range 15-63) years were available. In all the included studies, a posterior capsulotomy resulted in the restoration of knee extension to normal or nearly normal values (mean postoperative extension deficit: 0.4-4.2 degrees) with a significant increase in functional outcome scores. No neurovascular complications were reported within the studies. Due to the diverse methodology of studies, the direct comparison of arthroscopic versus open approaches was not possible. Concerning the risk of bias assessment, the greatest concerns raised the selection of participants among the included studies and the methods of outcome measurement. The certainty of evidence was very low according to the GRADE.

CONCLUSIONS

Both arthroscopic and open posterior capsulotomy of the knee results in restoration of normal or nearly normal knee extension and significant improvement in functional outcomes.

LEVEL OF EVIDENCE

IV.

Spinopelvic mismatch is associated with patient-reported outcome measures after total knee arthroplasty at a mean follow-up of 15 years

BACKGROUND

Total knee arthroplasty (TKA) is widely performed; yet, up to 25% of patients are dissatisfied with outcomes. Our aim was to evaluate the association between a spinopelvic mismatch and patient-reported outcomes after TKA.

METHODS

This was a retrospective study of 101 TKAs performed for osteoarthritis, at a mean 14.6 (range, 10.0-18.0) years post-surgery. Postoperative knee joint perception was evaluated as 'artificial', with or without restrictions, or 'natural'. Age, sex and the spinopelvic mismatch were compared between the 'artificial' (n = 54) and 'natural' (n = 47) perception groups. Multiple logistic regression analysis was used to identify predictive factors of an artificial perception, with a receiver operating characteristic curve to identify cut-off values for significant factors.

RESULTS

A spinopelvic mismatch, defined as a pelvic incidence minus lumbar lordosis (PI-LL) ≥ 10°, was associated with an artificial perception (odds ratio, 1.57; 95% confidence interval, 1.29-3.22; P = 0.023). An artificial joint perception was related to lower Knee Injury and Osteoarthritis Outcome Score-Joint Replacement (KOOS-JR, P = 0.021) and EuroQol 5-Dimension (EQ-5D, P = 0.025) scores. The cut-off PI-LL of 11° differentiated the groups with a sensitivity of 87.0% and specificity of 91.9%. Postoperative KOOS-JR (P < 0.001), EQ-5D (P = 0.014), satisfaction (P = 0.015), knee extension angle (P = 0.024), and perception (P = 0.032) differed between the groups when the PI-LL threshold was set at 10°.

CONCLUSION

A spinopelvic mismatch (PI-LL ≥ 10°) is associated with a risk of artificial perception of function after TKA. Measurement of the PI-LL could assist patients and surgeons to predict TKA outcomes.

Investigation of the Relationship Between Hip and Knee Osteoarthritis and Disordered Spinal and Pelvic Morphology

Introduction

A critical question is the causal relationship between hip or knee osteoarthritis (OA) and disordered spinal and pelvic morphology. The aim of this study is to examine this correlation. Therefore, we studied the effect of total hip or knee arthroplasty (THA/TKA) on truncal parameters to determine the causal relationship between these two situations.

Materials and methods

This is a prospective study of the effect of THA or TKA in patients with hip or knee OA on truncal morphological parameters. Patients with one-sided hip or knee OA who chose to undergo THA or TKA were enrolled and surveyed. A control group (CG) was also surveyed for comparison with the patients. The patients were preoperatively examined for truncal parameters using the Diers Formetric four-D analysis system (surface topography technique) to calculate several truncal parameters in all planes at four months and 12 months postoperatively. Measurable examinations were performed using the Statistical Package for the Social Sciences (SPSS) version 17.00 (SPSS Inc., Chicago), and statistical significance was set at a p-value of <0.05.

Results

The study examined 34 patients who underwent THA, including 19 women and 15 men with a mean age of 67.62 ± 8.28 years. The study also examined 45 patients who underwent TKA, including 34 women and 11 men, with a mean age of 72.42 ± 7.0 years. These patients were also compared with a CG that consisted of 25 normal individuals, including 12 women and 13 men, with a mean age of 69.28 ± 10.11 years.

The results of this study from four months after THA revealed that the lordotic angle, trunk torsion, pelvic inclination, pelvic obliquity, and pelvis rotation were improved to normal levels. At 12 months after THA, only the pelvic obliquity was improved to normal levels. At four months after TKA the lordotic angle, pelvic inclination, and pelvic obliquity were improved to normal levels. However, the fleche cervicale and vertebral rotation were worse. At 12 months after TKA, only the pelvic obliquity was improved to normal levels.

Conclusions

THA and TKA to correct hip and knee OA do not correct the disordered morphology of the trunk in the long term. Thus, hip or knee OA does not seem to be responsible for disordered trunk morphology. However, it cannot be ruled out whether the disturbed morphology is responsible for the appearance of the hip and knee OA.

Sagittal imbalance of the spine-pelvis-lower extremity axis associated with back-related disability

BACKGROUND

The impact of sagittal imbalance in patients has been reported in LBP and LBP-related disabilities due to spinopelvic imbalance. However, no reports investigating the spine-pelvis-lower extremity axis using lateral images have been reported thus far. This study introduced a novel parameter of the spine-pelvis-lower extremity axis and evaluated whether this parameter was related to symptoms.

METHODS

A total of 343 subjects were included in this cross-sectional study. Standing spine-pelvis and pelvis-lower extremity radiographs were obtained to assess the sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumbar lordosis, and thoracic kyphosis. The sacral-knee distance (SKD) (i.e., distance from the anterior femoral condyle to the vertical axis at the upper posterior edge of S1 body) was measured. Furthermore, the SVA/SKD ratio was calculated for global balance. Subjects were divided into leg compensated (LC; SVA/SKD ratio <0.8) and decompensated (LD; SVA/SKD ratio ≥0.8) groups. The SVA was divided into balanced spine (BS; SVA ≤40 mm) and imbalanced spine (IS; SVA >40 mm) groups. All individuals were classified into LC + BS, LC + IS, LD + BS, and LD + IS groups. The relationships among the four groups and low back pain (LBP), Oswestry Disability Index (ODI), and knee pain were examined.

RESULTS

SKD was significantly correlated with SVA, SS, PI, PT, and knee-femoral angle. ODI was significantly higher in the LC + IS group than in the LD + BS group (p < 0.05). Knee pain prevalence was significantly higher in the LC + IS and LC + BS groups than in the LD + IS group (p < 0.05).

CONCLUSION

SVA/SKD ratio is useful for evaluating global alignment. Our findings are significant because they highlight the importance of SKD with respect to knee pain, LBP, and LBP- related disabilities.

Understanding sagittal compensation in adult spinal deformity patients: relationship between pelvic tilt and lower-extremity position

OBJECTIVE

In adult spinal deformity (ASD), quantifying preoperative lower-extremity (LE) compensation is important in formulating an operative plan to achieve optimal global sagittal alignment. Whole-body radiographs are not always available. This study evaluated the possibility of estimating LE compensation without whole-body radiographs.

METHODS

In total, 200 consecutive ASD patients with full-body radiographic assessment were categorized into the following three groups according to their cranio-hip balance (distance from the cranial sagittal vertical axis to the hip axis [CrSVA-H]): group 1, anterior-shift (A-shift) group (CrSVA-H > 40 mm); group 2, balanced group, -40 mm < CrSVA-H < 40 mm; and group 3, posterior-shift (P-shift) group, CrSVA-H < -40 mm. After analyzing the correlation between CrSVA-H, pelvic tilt (PT), and LE parameters, the cutoff PT and PT/pelvic incidence (PI) values that correlated with the presence of LE compensation were determined. Previously published data from asymptomatic volunteers were used as a baseline threshold (sacrofemoral angle [SFA] > 217.0° and knee flexion angle [KA] > 11.0°).

RESULTS

Among the hip, knee, and ankle, only KA showed a significant increase in the A-shift group compared to the other two groups (p < 0.01). With a wide threshold (SFA > 208.0° and KA > 5.0°), 84.9% of the A-shift group showed LE compensation (hip or knee or both), which was a significantly greater percentage than those in the balanced and P-shift groups (48.4% and 51.9%, p < 0.01). With a narrow threshold (SFA > 217.0° and KA > 11.0°), 62.2% of the A-shift group showed any LE compensation, which was also a higher percentage than the other two groups. The CrSVA-H was moderately correlated with KA (r = 0.502), but had no correlation with PT, SFA, and ankle dorsiflexion angle (AA). PT showed a moderate/strong correlation with SFA, KA, and AA (r = 0.846, 0.624, and 0.622, respectively). With receiver operating characteristic curves, the authors determined that a 23.0° PT with PT/PI > 0.46 predicts the presence of any type of LE compensation with use of the wide threshold.

CONCLUSIONS

ASD patients with increased CrSVA-H, which represents cranio-hip anterior imbalance, demonstrated a higher prevalence of LE compensation, especially knee flexion, compared to those with neutral and posterior shift of CrSVA. PT represents the extent of LE compensation in patients with spinal sagittal malalignment. Using the cutoff value of PT determined in this study, surgeons can preoperatively estimate the extent of LE compensation without obtaining a full-body radiograph.

Impact of Preoperative Total Knee Arthroplasty on Radiological and Clinical Outcomes of Spinal Fusion for Concurrent Knee Osteoarthritis and Degenerative Lumbar Spinal Diseases

Concurrent knee osteoarthritis (KOA) and degenerative lumbar spinal disease (LSD) has increased, but the total knee arthroplasty (TKA) effect on degenerative LSD remains unclear. The aim of this study was to retrospectively analyze to compare radiological and clinical outcomes between spinal fusion only and preoperative TKA with spinal fusion for the patients with concurrent KOA and degenerative LSD. A total of 72 patients with concurrent KOA and degenerative LSDs who underwent spinal fusion at less than three levels were divided in two groups: non-TKA group (n = 50) and preoperative TKA group (n = 22). Preoperative lumbar lordosis (LL) was significantly lower in the preoperative TKA group than the non-TKA group (p < 0.05). Significantly higher preoperative pelvic incidence (PI), PI/LL mismatch, and pelvic tilt (PT) occurred in preoperative TKA group than non-TKA group (all p < 0.05). There was significant improvement of postoperative Oswestry Disability Index and leg Visual Analog Scale in the preoperative TKA group (all p < 0.01). Preoperative TKA could be a benefit for in proper correction of sagittal spinopelvic alignment by spinal fusion. Therefore, preoperative TKA could be considered a preceding surgical option for patients with severe sagittal spinopelvic parameters in concurrent KOA and degenerative LSD.

Rapid Destructive Arthropathy of the Knee in Parkinson's Disease with Pisa Syndrome: A Case of Knee-Spine Syndrome

The changes occurring in knee osteoarthritis often cause alterations in the spinal loading condition, which further lead to degenerative changes. This close relationship of the knee and spine has been reported as knee-spine syndrome. A 60-year-old woman with Parkinson's disease (PD; Hoehn-Yahr stage IV) had severe knee pain with moderate lateral osteoarthritis of the knee (Kellgren-Lawrence classification grade II). Conservative therapy had no effect at all, and the knee developed destructive osteoarthritis rapidly without any traumatic episodes. The radiographic findings progressed to Kellgren-Lawrence grade IV within a month. Magnetic resonance imaging revealed partial depression of the joint surface, including shredded ossicles and substantial amounts of synovial fluid. The imaging findings were considered to be caused by a subchondral insufficiency fracture (SIF). Total knee arthroplasty was performed using a semiconstrained prosthesis. The alignment of her lower extremity improved, and the patient could walk without knee pain. The patient had Pisa syndrome, a lateral flexion of the trunk, which is a postural deformity of the trunk secondary to long-standing PD. The postural deformity in PD is not based on spinal deformity itself but on the loss of postural reflexes and the imbalance of muscle tonus. Her left knee pain appeared 1 month after L1-L4 posterior lumbar interbody fusion (PLIF) as the Pisa syndrome to her left side worsened. The more the trunk tilts to the lateral side, the center of the gravity axis will shift and pass through more lateral points of the knee and result in higher knee load. The stress concentration from the spine to the lateral joint of the knee caused lateral knee osteoarthritis, namely, knee-spine syndrome. When patients undergo correction surgery for adult spinal disorder with impairment of postural reflexes, they need to be followed up carefully regarding not only the spinal alignment but also the lower extremities.

Progression of pelvic retroversion is a critical factor for clinical outcome after Opening-wedge high tibial osteotomy among elderly patients

Purpose

To evaluate the clinical outcome after opening-wedge high tibial osteotomy (OWHTO) and to determine the critical factors for a poor clinical outcome after OWHTO in patients aged over 65 years.

Methods

Our retrospective analysis was based on the data from 233 patients who underwent OWHTO for medial compartment knee OA at our institution between January 2013 and December 2018, and 88 patients (36 men and 52 women) over 65 years of age were included in this study. Radiographic parameters of weight-bearing line ratio (WBLR) and pelvic inclination (PI); the knee function, range of motion (ROM) and extension; and clinical outcome with Lysholm score were obtained preoperatively and postoperatively at the final follow-up visit. To evaluate the critical factors for the clinical outcome, univariate regression analysis was used to identify the relationship between postoperative and improved Lysholm score and pre-and post-operative essential factors. To reveal the factor having a greater impact on the clinical outcome, a p < 0.05 in univariate factors was entered into a multivariate regression analysis.

Results

The preoperative WBLR was significantly changed, and Lysholm score improved from 59.5 to 81.5 (p < 0.0001), whereas the PI, knee extension and ROM were not changed after OWHTO. Regarding the essential factors affecting clinical outcome after OWHTO, age and delta PI were negative, whereas preoperative WBLR, postoperative ROM, especially extension, had a positive effect (p < 0.05). Furthermore, only delta PI had affected the improvement of clinical outcome with OWHTO (p < 0.01), and postoperative knee extension was negatively correlated with the progression of pelvic retroversion (p < 0.01).

Conclusion

Age at surgery and progression of pelvic retroversion were the critical factors for poor postoperative clinical outcomes after OWHTO. Care should be taken for the progression of pelvic retroversion after OWHTO because it deteriorates the clinical outcome by inducing the knee flexion contracture as the compensatory mechanism for the balance of sagittal alignment.

Association of Lumbar Degenerative Disease and Revision Rate following Total Knee Arthroplasty

Recently, a variety of studies have analyzed the potential correlation between lumbar degenerative disease (LDD) and inferior clinical outcomes after total hip arthroplasty. However, there has been limited data concerning the role of LDD as a risk factor for failure after total knee arthroplasty (TKA). The aim of our study was to determine: (1) what is the association of LDDs with TKA failure (all-cause revision) within 2 years of index arthroplasty and (2) if patients with LDD and lumbar fusion are at increased risk of TKA revision within 2 years compared with LDD patients without fusion. Data were collected from the Humana insurance database using the PearlDiver database from 2007 to 2017. To assess aim 1, patients were stratified into two groups based on a prior history of LDD (International Classification of Diseases [ICD]-9 or -10 diagnostic codes). To analyze aim 2, patients within the LDD cohort were stratified based on the presence of lumbar fusion (lumbar fusion Current Procedural Terminology code). All-cause revision rate was 3.4% among LDD patients versus 2.4% of patients with non-LDD (p < 0.001) at 2 years. Following multivariate analysis, LDD patients were at increased risk of all-cause revision surgery at 2 years (odds ratio [OR]: 1.361; 95% confidence interval [CI]: 1.238-1.498; p < 0.001) as well as aseptic loosening (OR: 1.533; 95% CI: 1.328-1.768; p < 0.001), periprosthetic joint infection (OR: 1.245; 95% CI: 1.129-1.373; p < 0.001), and periprosthetic fracture (OR: 1.521; 95% CI: 1.229-1.884; p < 0.001). Among LDD patients, patients who have a lumbar fusion had an all-cause revision rate of 5.0%, compared with 3.2% among LDD with no lumbar fusion patients at 2 years (p = 0.021). Following multivariate analysis, lumbar fusion patients were at increased risk of all-cause revision surgery (OR: 1.402; 95% CI: 1.362-1.445; p = 0.028), aseptic loosening (OR: 1.432; 95% CI: 1.376-1.489; p = 0.042), and periprosthetic fracture (OR: 1.302; 95% CI: 1.218-1.392; p = 0.037). Based on these findings, TKA candidates with preoperative LDD should be counseled that TKA outcome may be impaired by the coexistence of lumbar spine degenerative disease. This is Level III therapeutic study.

Effects of Total Knee Arthroplasty on Coronal and Sagittal Whole-Body Alignments: Serial Assessments Using Whole-Body EOS

BACKGROUND

The aims of this study were to evaluate the effects of correcting lower limb alignment by total knee arthroplasty (TKA) on the spinopelvic alignment and to identify patients with difference in the knee joint between clinically measured passive motion and the actual standing posture.

METHODS

In this retrospective study, 101 patients who underwent TKA and whose serial whole-body EOS X-ray were available were included. The relationship of the knee and spinopelvic alignment was analyzed by evaluating the parameters of standing anterior-posterior and lateral whole-body EOS X-ray. The differences between postoperative passive motion and weight-bearing posture in the knee joint were assessed in both coronal and sagittal planes. Furthermore, the causes of such differences were analyzed.

RESULTS

Significant correlations between Δpelvic obliquity and coronal ΔHip-Knee-Ankle (HKA)_Rt-Lt angle between the preoperative and 3-month and 1-year postoperative data (p < 0.001 and p < 0.005, respectively) and improved with coronal lower limb alignment close to neutral resulted in decreased pelvic obliquity (p < 0.001, ß = 0.085 and p = 0.005, ß = 0.065, respectively) were observed. The correlations between Δpelvic tilt (PT) and Δsacral slope (SS) and sagittal ΔHKA_Rt-Lt angle were statistically significant (PT: p < 0.001 and p < 0.045; SS: p = 0.002 and p < 0.001, respectively). The improved sagittal alignment close to neutral resulted in decreased PT and increased SS. The difference between postoperative passive motion and the weight-bearing posture of the knee joint was correlated with lumbar lordosis and sagittal C7 plumb line-sacrum distance (p = 0.042 and p < 0.001, respectively).

CONCLUSIONS

The correction of lower limb alignment with TKA affected pelvic parameters dominantly; however, there was little effect on the spinal alignment. Additionally, patients with anterior stooping or lumbar flat back demonstrated difference in extension between passive knee motion and standing. Therefore, rather than only focusing on changes in the knee alignment correction, knee surgeons should also evaluate the spinopelvic alignment before surgery to consider the prognosis of the standing and predict the possible changes in the whole-body alignment. This preoperative assessment may improve the prognosis of TKA.

The Impact of Concomitant LOW Back Pain (LBP) on Functional Outcomes in Total Ankle Arthroplasty (TAA)

Although numerous studies have demonstrated that concomitant low back pain (LBP) is associated with worse functional outcomes in patients undergoing total hip and knee arthroplasty, no study has analyzed its impact on patients undergoing total ankle arthroplasty (TAA). The aim of this study was to determine the prevalence of LBP in people undergoing TAA and analyze its impact on patient reported functional outcome measures (PROMs). A retrospective review was performed on data from the Vancouver End Stage Ankle Arthritis Database. In total, 87 patients undergoing TAA were studied, with patient demographics collected preoperatively, including the absence or presence of LBP. Postoperative follow-up was performed at 5 years, primarily analyzing disease-specific PROMs including the Ankle Osteoarthritis Score and Ankle Arthritis Score. The Short Form-36 was used as a secondary outcome measure to assess global function. Multivariable linear mixed-effects regression models were conducted to compare the PROM between patients with LBP with those without LBP. In total, 30 patients (35%) presented with concomitant LBP. There were no significant differences at baseline between the LBP group and no LBP group in terms of demographics or baseline primary disease-specific PROMs. At 5 years, the patients with LBP had significantly worse Ankle Arthritis Score (32 ± 23 vs 22 ± 17, p = .03), Ankle Osteoarthritis Score Total (34 ± 23 vs 22 ± 16, p = .01), and Short Form-36 physical (PCS) components summaries (33 ± 12 vs 44 ± 9, p = .001) compared to the no-LBP group. Both groups improved significantly from baseline across all outcome measures. Our study demonstrated that the prevalence of concomitant LBP in end stage ankle arthritis undergoing TAA is similar to that described in arthritic knees and hips. If present, it can be associated with worse functional outcomes in the intermediate term. However it is not a contraindication to surgery, with patients still experiencing significant improvements from baseline. Further studies are needed to evaluate if LBP influences complications, implant failure rates and survival.

Truncal Changes in Patients Suffering Severe Hip or Knee Osteoarthritis: A Surface Topography Study

Backgroud

Osteoarthritis (OA) of the hip and knee is a degenerative disease with complications, including reduced range of motion and pain. Although OA of the hip and knee is common, there are few studies that investigated if patients with this condition had affected morphological truncal parameters. The objectives of this study were to compare the morphology of the spine and the pelvis of patients with hip or knee OA to that of a control group (CG) and to comment on the proposed mechanisms of these changes and the clinical effects on patients.

Methods

This study included three groups of individuals. The first group consisted of 34 patients (15 men and 19 women with a mean age of 67.62 ± 8.28 years) suffering from hip OA. The second group consisted of 45 patients (11 men and 34 women with a mean age of 72.47 ± 7.0 years) suffering from knee OA. These patients were compared with a CG, which consisted of 25 individuals (13 men and 12 women with a mean age of 69.28 ± 10.11 years). The DIERS formetric 4D analysis system was used to calculate several truncal parameters in all planes. All analyses were accomplished using the SPSS ver. 17.0, and p < 0.05 was used to determine statistical significance.

Results

Patients with hip OA presented with significantly increased values than those in the CG for sagittal imbalance, scoliosis angle, vertebral rotation, trunk torsion, and pelvic obliquity, and decreased values than those in the CG for fleche lombaire. Patients with knee OA presented with significantly increased values than those in the CG for sagittal imbalance, apical deviation, scoliosis angle, vertebral rotation, trunk torsion, and pelvic obliquity. Patients with hip or knee OA, compared to the CG, had greater forward inclination of the spine, greater scoliosis, greater vertebral rotation and trunk torsion, and greater obliquity of the pelvis at the frontal plane.

Conclusions

Patients with severe hip or knee OA could have truncal morphology alterations, in addition to reduced hip or knee range of motion and pain. These alterations could cause significant negative effects, which may then seriously affect the patients' quality of life.

Relationships between the changes in flexion contracture and standing flexion angle of the knee and sagittal spinal alignment after total knee arthroplasty

BACKGROUND

The sagittal spinal alignment interacts with the lower extremity in patients with combined degenerative disease of the spine and lower extremity. This study aimed to clarify the relationships between the reciprocal changes in sagittal alignment of the knee, pelvis, and spine after total knee arthroplasty (TKA) in osteoarthritis patients.

METHODS

Prospectively, 36 patients who underwent primary TKA for severe knee osteoarthritis were enrolled. Their clinical and radiological evaluation included assessments of the knee flexion contracture (KFC) and standing knee flexion angle (KFA), as well as spinopelvic parameters and the global sagittal spinal alignment from standing whole-lower-extremity and whole-spine radiographs preoperatively and at postoperative 2 weeks, 6 weeks, 6 months, 1 year, and 2 years. Linear mixed models were used to assess the relationships between KFC/KFA and between spinopelvic/global sagittal spinal alignments.

RESULTS

The KFC decreased abruptly immediately after TKA, and the correction was maintained for 2 years postoperatively. The KFA decreased gradually and approached the value of the KFC after 2 years. Of the spinopelvic parameters, sacral slope and pelvic incidence decreased significantly, in ways related to changes in KFA. There was no significant relationship between sagittal spinal alignment and postoperative changes in KFC.

CONCLUSION

Although the flexion contracture was corrected immediately after TKA, the standing KFA improved gradually over 2 years. The pelvic parameters showed compensatory changes according to the KFA. The decompensated sagittal spinal malalignment was not related to a relapse in flexion contracture.

Coexistence of low back pain and lumbar kyphosis is associated with increased functional disability in knee osteoarthritis: the Nagahama Study

OBJECTIVE

To examine the association of low back pain (LBP) and lumbar kyphosis with functional disabilities and knee symptoms in patients with knee osteoarthritis (OA).

METHODS

We analyzed 586 participants (80.1% female; age, 68.8 ± 5.2 years) from the Nagahama Study who were aged ≥60 years and had radiographically confirmed knee OA. The Knee Scoring System (KSS) was used to assess functional disabilities and knee symptoms. LBP was defined as the presence of any persistent back pain for more than 3 months. Lumbar kyphosis was determined by skin-surface methods using a computer-aided electronic device called the Spinal Mouse. Multiple linear regression analysis was used for assessing the association of LBP and lumbar kyphosis with the KSS scores. Subgroup analyses based on sex were also performed.

RESULTS

LBP and lumbar kyphosis were independently associated with a lower KSS function score after adjustment for covariates (mean difference [95%CI, confidence interval] = -4.96 [-7.56 to -2.36] points for LBP alone, -4.47 [-8.51 to -0.43] points for lumbar kyphosis alone, and -13.86 [-18.86 to -8.86] points for the coexistence of LBP and lumbar kyphosis, respectively). The coexistence of LBP and lumbar kyphosis in women was associated with a lower KSS symptom score (mean difference [95%CI] = -4.49 [-6.42 to -2.55] points).

CONCLUSION

These findings suggest that both LBP and lumbar kyphosis are useful clinical signals indicating functional disability and knee symptoms in patients with knee OA.

Total knee arthroplasty for patients with medial knee osteoarthritis improves trunk movement during gait

BACKGROUND

Previous studies have indicated that the kinematics of the knee joint affect the trunk and pelvis during gait. However, the factors that influence trunk movement in knee osteoarthritis patients during gait after surgery remain unclear.

OBJECTIVE

To examine the effect of total knee arthroplasty (TKA) on trunk movement during gait by comparing knee osteoarthritis patients with healthy controls.

METHODS

Fourteen medial knee osteoarthritis patients who underwent initial unilateral TKA and 11 controls participated in this study. Knee and hip joint flexion and trunk and pelvic tilts during gait were acquired using a three-dimensional motion analysis system. Knee joint range of motion, pain, and kinematic data were collected preoperatively and 1 year postoperatively for knee osteoarthritis patients.

RESULTS

Knee extension limitation and pain significantly improved postoperatively compared with preoperative stages. Preoperatively, the peak anterior trunk tilt during the stance phase was significantly larger in osteoarthritis patients than in controls. The peak anterior trunk tilt during the stance phase was significantly smaller postoperatively than at preoperative stages.

CONCLUSIONS

These results suggest that after TKA, the trunk movements of knee osteoarthritis patients were approximately equal to those of controls, with improvement in clinical outcomes such as knee extension limitation and pain.

Spinopelvic Alignment and Low Back Pain before and after Total Knee Arthroplasty

STUDY DESIGN

Prospective cohort study.

PURPOSE

This study aims to examine changes in spinopelvic alignment, sagittal global balance, and low back pain (LBP) following the removal of knee flexion contracture by total knee arthroplasty (TKA).

OVERVIEW OF LITERATURE

The limitation of the knee extension was correlated with the decrease in lumbar lordosis (LL). Currently, there are no studies evaluating the spinopelvic alignment and LBP before and after TKAs.

METHODS

Sagittal spinopelvic alignment was evaluated in 110 subjects using radiographs of the whole spine. Parameters measured in this study included sagittal vertical axis (SVA), LL, sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI). The distribution of sagittal plane modifier grade was evaluated according to the Scoliosis Research Society-Schwab classification of adult spinal deformity (ASD). Consequently, personal history related to LBP was obtained, and the association of pre- and postoperative LBP and spinopelvic alignment was investigated.

RESULTS

Preoperatively, 66% of all subjects showed LBP and mostly exhibited anteriorly shifted global imbalance associated with a decrease in LL and knee flexion contractures, and the subject who had severe flexion contracture of the knee joint showed more forwardly shifted global balance with backward PT and decrease in LL. After TKAs, the knee flexion contractures were eliminated in most cases, and one-third of subjects experienced decrease in LBP. However, SVA increased more and associated with slight decrease of PT and increase of SS. No significant differences were confirmed between pre- and postoperative values of LL and PI. In addition, there were no significant differences in postoperative values of spinopelvic parameters between subjects with and without relieved LBP.

CONCLUSIONS

Although one-third of subjects experienced decrease of LBP after TKAs, the sagittal global imbalance was not restored through the removal of knee flexion contracture.

Knee Flexion Angle Following Total Knee Arthroplasty Relates to a Preoperative Range of Motion of the Hip

BACKGROUND

Many factors have been reported to affect postoperative range of knee flexion after total knee arthroplasty (TKA); however, no study has reported the impact of preoperative range of motion of the hip to the postoperative flexion angle of the knee thus far.

METHODS

Of 38 consecutive patients who underwent posterior-stabilized TKA, we assessed 21 patients after excluding 17 patients who met exclusion criteria. The range of motion of the knee and the hip, age, body-mass index, serum albumin level, HbA1c, Kellgren-Lawrence grade, knee extension strength and radiological femorotibial angle as well as postoperative knee flexion angle at three months were evaluated. The preoperative data and the knee flexion angle at three months after TKA were compared using Spearman's rank correlation coefficient.

RESULTS

Knee flexion angle at three months after TKA was positively correlated with preoperative flexion (ρ = 0.616, p = 0.007) and external rotation angle (ρ = 0.576, p = 0.012) of the hip as well as preoperative knee flexion angle (ρ = 0.797, p = 0.001). There were no correlations between postoperative knee flexion angle and other preoperative data.

CONCLUSIONS

Patients with restricted flexion and/or external rotation of the hip may have contractures of Gluteus maximus, Gluteus medius and Tensor fasciae latae, which can cause hypertension of iliotibial tract. It may cause decreased internal rotation of the tibia when the knee is flexed, which affects postoperative knee flexion angle, thus limited flexion and/or external rotation of the hip might restrict knee flexion angle following TKA.

Radiographic and clinical evidence: osteoarthritic knee can change surgical result for lumbar degenerative disease patient undergone surgery for 3-year follow-up: a retrospective comparative clinical study

Background

There is a paucity of reports clarifying the implication of knee osteoarthritis (OA) on spinal sagittal alignment of patients undergone surgery for lumbar spine. This study aimed to analyze how osteoarthritic knee affects radiographic and clinical results of degenerative lumbar disease patients undergone lumbar fusion.

Methods

We retrospectively reviewed the medical records and radiographs of 74 consecutive degenerative lumbar disease patients who underwent posterior instrumentation and fusion surgery between May 2016 and June 2017 and were followed up for minimum 3 years postoperatively. The patients were divided into 2 groups according to the severity of knee OA by Kellgren-Lawrence grading (KLG) scale (group I, KLG 1 or 2 [n = 39]; group II, KLG 3 or 4 [n = 35]). Patient demographic data, comorbidities, spinal sagittal parameters and clinical scores were extracted and compared at preoperative, postoperative 1 month and the ultimate follow-up between the groups. In radiographic assessment, sagittal alignment parameters and sagittal balance were used. In clinical assessment, the scores of Oswestry disability index (ODI) and Scoliosis Research Society questionnaire (SRS-22) were used. For the frequency analysis of categorical variables across the groups, chi-square test was used and student t tests was used to compare the differences of continuous variables.

Results

In radiographic assessment, TLK (thoracolumbar kyphosis), LL (lumbar lordosis), PT (pelvic tilt), C7 SVA (sagittal vertical axis) in both groups improved significantly after surgery (p <  0.05). However, LL, PT, C7SVA improved at postoperative 1 month in the group II were not maintained at the ultimate postoperative follow-up. In clinical assessment, preoperative Oswestry disability index (ODI, %) and all SRS-22 subscores of the group I and II were not different (p > 0.05). There were significant differences between the groups at the ultimate follow-up in ODI (− 25.6 vs − 12.1, p <  0.001), SRS total score (%) (28 vs 20, p = 0.037), function subscore (1.4 vs 0.7, p = 0.016), and satisfaction subscore (1.6 vs 0.6, p < 0.001).

Conclusion

Osteoarthritic knee with KLG 3 or 4 have a negative influence on maintaining postoperative spinal sagittal alignment, balance, and the clinical outcomes achieved immediately by posterior instrumentation and fusion for lumbar degenerative disease.

Trial registration

This study was retrospectively registered with approval by the institutional review board (IRB) of our institution (approval number: 2018–11-007).

Correction surgery for adult spinal deformity improves not only spinopelvic alignment but also the three-dimensional alignment of the lower extremities

BACKGROUND

It is well known that correction surgery for adult spinal deformity (ASD) improves sagittal and coronal spinopelvic alignment, but the surgery effect on lower extremities (LE) is not well clarified. The aim of this study was to test the hypothesis that LE alignment also improves following spinopelvic correction surgery for ASD as a function of compensatory mechanism, and to clarify an effect of the severity of knee osteoarthritis (OA) on the improvement.

METHODS

We retrospectively evaluated spinopelvic alignment, hip knee ankle angle (HKA), knee flexion angle (KF), and severity of the knee OA in thirty-nine patients with ASD before, two weeks and three months after the surgery. The grade of knee OA was evaluated by Kellgren Lawrence grading, and classified grade 0 to 2 into mild, and 3, 4 into severe OA. All the values were compared by paired t test or Wilcoxon signed rank test with significant p value of <0.05.

RESULTS

Following the surgery, not only spinopelvic, but also bilateral HKA and KF were significantly improved. HKA in mild OA side was more normalized compared to that in severe side. Although KF of both bilateral mild and bilateral severe OA groups improved, the improvement of mild group was more significant.

CONCLUSION

The 3D alignment of LE improved following spinopelvic correction surgery. The improvement was inadequate in cases with severe knee OA.

Spinal Flexibility Is an Important Factor for Improvement in Spinal and Knee Alignment after Total Knee Arthroplasty: Evaluation Using a Whole Body EOS System

The purposes of this study were (1) to evaluate the relationship between lumbosacral flexibility and the effects of total knee arthroplasty (TKA) on whole-body alignment; and (2) to determine the prerequisites of the adjacent joints for successful TKA. A total of 116 patients (156 cases) who had whole-body X-ray and flexion-extension lumbar radiograph available were enrolled. For the sagittal alignment evaluation, hip-knee-ankle (HKA) angle, pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), and C7 plumb line-sacrum distance (SVA) were evaluated on the whole-body radiographs. Lumbar flexibility (LF) was evaluated using the flexion-extension lumbar radiographs, and pelvic flexibility (PF) was evaluated using the pelvic incidence (PI). The disparities in the knee joint between postoperative passive motion and weight-bearing posture were assessed. LF was significantly correlated with ΔLL and ΔSVA (LL: p = 0.039, SVA: p = 0.040; Pearson correlation coefficient (PCC): -0.206 and 0.205, respectively). There were correlations between PF and ΔSS (p < 0.001, PCC: -0.362), and between the disparity and LF (p = 0.005, PCC = -0.275). Linear regression analysis demonstrated that LF was significantly associated with the presence of disparity (p = 0.005, β = -0.205). LF is an important factor for improved spinal and lower limb alignment after TKA. Additionally, reduced LF may result in knee joint disparity between passive extension and standing extension status. Therefore, surgeons should consider spinopelvic alignment, including lower limb alignment preoperatively, to be able to predict possible changes in whole-body alignment following TKA.

Cervical spine degenerative disease is an independent risk factor for increased revision rate following total knee arthroplasty

INTRODUCTION

The relationship between cervical degenerative pathology and total knee arthroplasty (TKA) revision rates is not well understood. The aim of the study was to determine whether cervical spine degenerative diseases have a role in complications following TKA within 2 years.

METHODS

Data were collected from the Humana insurance database using the PearlDiver Patient Records Database from 2007-2017. Patients who had a primary TKA were identified using Current Procedural Terminology (CPT) code 27,447, and patients with degenerative cervical disease were identified using CPT and International Classification of Diseases (ICD) codes. Data on patients' demographics, comorbidities and postoperative complications were recorded and analyzed with univariate and multivariate analysis with significance set at p < 0.05. A Kaplan-Meier analysis was conducted to estimate the 1- and 2-year rates of survival free from revision.

RESULTS

A total of 81,873 patients were included in this study. Following multivariate analysis, cervical spine degenerative disease patients were at increased risk of all-cause revision surgery following 1 year (OR: 1.342 95% CI: 1.149-1.569; p < 0.001) and 2 year (OR: 1.338; 95% CI: 1.184-1.512; p < 0.001). At 2 years, patients with cervical spine degenerative disease had a survival rate of 97.7%, while the survival rate was 99.2% among the non-cervical degenerative cohort.

CONCLUSIONS

Based on these results, patients with cervical spine degenerative pathology should be counseled that their spinal pathology may impair outcomes following TKA.