Worse Patient-Reported Outcomes and Spino-Pelvic Parameters After Total Hip Arthroplasty for Rapidly Progressive Osteoarthritis of the Hip Compared to Osteoarthritis: A Propensity-Matched Cohort Study.

BACKGROUND: This study aimed to assess the association between the disease process of hip osteoarthritis and total hip arthroplasty (THA) outcomes; this is a critical issue, as rapid progression has been postulated to be responsible for patient dissatisfaction after THA. METHODS: This retrospective case-control study included 255 patients who underwent THA and completed a mean follow-up duration of 42.1 months (range, 24.0 to 77.0). We classified patients into those who had (n = 26) and did not have (n = 229) rapidly progressive osteoarthritis of the hip (RPOA), defined as a narrowing rate of joint space ≥ 2 mm yearly or a ≥ 50% loss within 12 months, excluding any other cause of a destructive arthropathy. Propensity score-matched cohorts for age, sex, body mass index, and spino-pelvic measures were created, and the outcomes were compared between the 2 groups. RESULTS: After successfully matching RPOA (n = 25) and non-RPOA patients (n = 50), there were significant differences in minimum clinically important difference (P = .009 for European Quality of Life 5-Dimension, and P < .001 for low back pain), patient acceptable symptom state (P = .015 for European Quality of Life 5-Dimension, and P < .001 for Hip Disability and Osteoarthritis Outcome Score Joint Replacement score), patient satisfaction (P = .028), and T1 pelvic angle as an indicator of global sagittal spinal deformity (P = .017). There was a correlation between T1 pelvic angle and low back pain in the RPOA group (R = 0.628, P < .001). CONCLUSIONS: Patients who exhibited RPOA before undergoing THA showed worse patient-reported outcomes compared with those who did not have rapid progression. Our study highlights the critical role of the disease process in influencing THA outcomes, advocating for a paradigm shift toward more meticulous preoperative evaluations, including global spinal deformity, standardized diagnostic criteria, and tailored interventions.

Factors associated with the progression of sagittal spinal deformity after total hip arthroplasty: a propensity score-matched cohort study.

PURPOSE: The functional interaction between the hip and spine in patients undergoing total hip arthroplasty (THA) is clinically significant, as it impacts post-operative outcomes. Therefore, this study aimed to identify factors associated with the progression of sagittal spinal deformity and assess the association with patient-reported outcomes. METHODS: This retrospective case-control study included 200 patients who underwent primary THA and completed a mean follow-up duration of 42.2 months (range, 24.0-78.0). We employed a multivariate logistic regression to identify variables predictive of a post-THA sagittal vertical axis (SVA) ≥ 50 mm, which was indicative of a spinal sagittal imbalance. Propensity score-matched cohorts for age, sex, body mass index, follow-up duration, hip flexion contracture, developmental dysplasia, pelvic incidence (PI), and SVA were created, and the outcomes were compared between the two groups. RESULTS: PI (odds ratio 1.39; 95% confidence interval 1.04-1.86, p = 0.033) was associated with an SVA ≥ 50 mm. After successfully matching patients with (n = 50) and without (n = 50) an SVA ≥ 50 mm, the minimum clinically important difference showed significant differences between the 50 matched pairs (p = 0.016 for EuroQol-5D, p = 0.003 for Hip Disability and Osteoarthritis Outcome Score Joint Replacement, and p < 0.001 for low back pain). CONCLUSION: PI is associated with the development of a positive sagittal spinal malalignment post-THA. This finding can assist surgeons in managing patient expectations and in optimising outcomes. Feasible strategies are warranted to minimise the risk of spinal deformity progression post-THA.

The psoas muscle index as a useful predictor of total hip arthroplasty outcomes.

INTRODUCTION: The aim of this study is to assess the association between the psoas muscle index (PMI) and total hip arthroplasty (THA) outcomes. This is a critical issue as sarcopenia has been associated with poor patient satisfaction post-THA. MATERIALS AND METHODS: This was a retrospective case-control study of 205 THAs, with a mean follow-up of 3.6 (range, 2.0-5.5) years. Age, sex, serum immune markers, spinopelvic parameters, PMI (quantified as the cross-sectional area of the psoas, bilaterally, at L3 divided by the individual's height squared), and patient-reported outcomes were compared between patients 'with' (n = 118) and 'without' (n = 87) achievement of a minimum clinically important difference (MCID) improvement in the EuroQol 5-Dimension (EQ-5D), post-THA. Logistic regression and receiver operating characteristic curve analyses were used to identify predictive factors. RESULTS: A ≥ MCID improvement in the EQ-5D was associated with the PMI (odds ratio, 0.75; 95% confidence interval, 0.63-0.91; P = 0.028), prognostic nutritional index (odds ratio, 0.85; 95% confidence interval, 0.45-0.94; P = 0.043), and age (odds ratio, 1.09; 95% confidence interval, 1.01-1.18; P = 0.044). After adjusting the PMI threshold to 4.0 cm2/m2 for females and 6.4 cm2/m2 for males, there were significant differences in serum factors (P = 0.041 for albumin and P = 0.016 for a prognostic nutritional index < 40), MCID (P < 0.001 for EQ-5D, P < 0.001 for low back pain, and P = 0.008 for the Hip Disability and Osteoarthritis Outcome Score Joint Replacement score), patient satisfaction (P = 0.003), and T1 pelvic angle (P = 0.030). CONCLUSION: The PMI, which is associated with nutritional status and global sagittal spinal deformity, does predict THA outcomes. Therefore, it can be useful when discussing THA expectations with patients.

T1 pelvic angle is associated with rapid progression of hip arthrosis.

PURPOSE: To evaluate the association between global spinal malalignment and rapid progression of hip arthrosis. METHODS: This was a retrospective, case-control study including 90 patients, contributing 90 hips, who underwent hemi- or total hip arthroplasty at our institution. For analysis, hips were classified into a rapid progression group, defined as ≥ 2 mm destruction of the femoral head or loss of the hip joint space within a 12-month period (n = 30), and a non-rapid progression group, defined by no observable hip disease progression over a period more than 12 months (n = 60). Logistic regression analysis identified factors that predicted rapid progression, with a receiver operating characteristic curve analysis used to confirm factors. RESULTS: Significant between-group differences were identified for the following parameters: pelvic tilt (P = 0.002, PT), sagittal vertical axis (P = 0.002, SVA), and T1 pelvic angle (P < 0.001, TPA). On multiple logistic regression, PT (P = 0.002), SVA (P = 0.002), and TPA (P < 0.001) were predictive of a rapid progression on hip arthrosis, with the area under the curve being greater for TPA than PT (P = 0.035). CONCLUSION: Global spinal alignment is associated with rapid progression of hip arthrosis. TPA could assist in identifying patients at risk for rapid progression of hip arthrosis, allowing for time management.

Clinical significance of relative pelvic version measurement as a predictor of low back pain after total hip arthroplasty.

PURPOSE: To evaluate the association between the preoperative global alignment and proportion (GAP) score and low back pain (LBP) after total hip arthroplasty (THA). METHODS: This was a retrospective case-control study of 200 patients who underwent primary unilateral THA for hip osteoarthritis. The following variables were compared between individuals with (n = 76) and without (n = 124) LBP after THA over a mean follow-up of 2 years: age, sex, GAP score, and patient-reported outcome measures. Logistic regression and receiver operating characteristic curve analyses were used to detect predictive factors. RESULTS: The following parameters were predictive of post-THA LBP: relative pelvic version (RPV) <-7° (odds ratio, 1.43; 95% confidence interval, 1.10-1.72; P = 0.032) and relative lumbar lordosis <-15° (odds ratio, 1.13; 95% confidence interval, 1.04-2.13; P = 0.041) preoperatively. Using an RPV cutoff value of - 7° (specificity 61/64 = 0.953; sensitivity 121/136 = 0.890), there were significant between-group differences in LBP visual analog scale (P = 0.020), Oswestry Disability Index (ODI, P = 0.014), EuroQol 5-Dimension (P = 0.027), Hip Disability and Osteoarthritis Outcome Score Joint Replacement (HOOS JR, P = 0.012), patient satisfaction (P = 0.024). There was clinically meaningful improvement for LBP visual analog scale (P = 0.001), ODI (P = 0.004), and HOOS JR (P < 0.001). The RPV before THA was correlated with HOOS JR (r = 0.773, P = 0.012) and ODI (r = - 0.602, P = 0.032) postoperatively. CONCLUSION: Among the GAP score, a moderate-to-severe pelvic retroversion was significantly associated with LBP post-THA. The RPV measurement may be a useful predictor of THA outcome, which may influence patient satisfaction.

The significance of the pelvic incidence measurement as a possible predictor of TKA outcome.

PURPOSE: To evaluate the association between the sagittal alignment of the pelvis and residual knee flexion contracture after total knee arthroplasty (TKA). This is important as a flexion contraction can be associated with the risk of poor outcomes and patient satisfaction after TKA. METHODS: This was a retrospective, case-control, study of 200 osteoarthritic knees, contributed by 200 patients, over a mean follow-up of 2.4 years. The following factors were compared between patients 'with' (46 knees) and 'without' (154 knees) a residual flexion contracture ≥ 10° after TKA: age, sex, pelvic incidence (PI), anterior femoral bowing, femoral component flexion angle (FFA), and patient-reported outcomes. Logistic regression and receiver operating characteristic curve analyses were used to identify predictive factors. RESULTS: The following factors were predictive of a residual flexion contracture ≥ 10°: a pelvic incidence ≥ 55° (odds ratio, 1.29; 95% confidence interval, 1.05-1.59; P = 0.031) and the FFA (odds ratio, 1.08; 95% confidence interval, 1.03-1.14; P = 0.044). A pelvic incidence cutoff of 55° yielded a significant between-group difference, with a sensitivity of 78.4% and specificity of 89.9% to differentiate a residual knee flexion contracture ≥ 10° (P = 0.001), patient satisfaction (P = 0.029), EuroQol 5-Dimension score (P = 0.028), anterior femoral curvature (P = 0.031), and Knee Injury and Osteoarthritis Outcome Score-Joint Replacement score (P = 0.046). CONCLUSION: A pelvic incidence > 55° is associated with a residual knee flexion contracture ≥ 10° after TKA. The significance of the pelvic incidence measurement as a possible predictor of TKA outcome was highlighted, including its impact on patient satisfaction. LEVEL OF EVIDENCE: III.

Association of the Psoas Muscle Index and Sagittal Spinal Alignment With Patient-Reported Outcomes After Total Hip Arthroplasty: A Minimum 5-Year Follow-Up.

BACKGROUND: The aim of this study is to assess the association between a spinopelvic malalignment and patient-reported perception of the hip as being "artificial" after total hip arthroplasty (THA). This is a critical issue as an age-related spinopelvic mismatch has been postulated to be associated with the risk of poor outcomes after THA. METHODS: This is a retrospective case-control study of 274 THAs (244 of whom were women), with a mean follow-up of 6.2 (range 5.0-8.2) years. Hip perception was assessed by asking subjects whether their joint felt "natural" or "artificial." The association between an artificial perception and the following factors was evaluated: age, gender, psoas muscle index (PMI, cross-sectional area of bilateral psoas at L3 divided by height squared), and spinopelvic measures using logistic regression analysis. RESULTS: An artificial hip perception (130 hips, 47.4%) was associated with a lower PMI (P = .016), Hip Disability and Osteoarthritis Outcome Score Joint Replacement score (P = .035), EuroQol 5-Dimension score (P = .041), and a higher incidence of a pelvic incidence-minus-lumbar lordosis (PI-LL) mismatch >10° (P < .001). A flatback deformity (odds ratio 2.24, 95% confidence interval 1.22-6.31, P = .001) and PMI (odds ratio 0.61, 95% confidence interval 0.34-0.82, P = .012) were predictive of an artificial perception. With the threshold of PI-LL set to 10°, PMI (P = .034), Hip Disability and Osteoarthritis Outcome Score Joint Replacement score (P < .001), joint perception (P = .020), EuroQol 5-Dimension score (P = .028), pain (P = .031), and satisfaction (P < .001) differed between the 2 groups. CONCLUSION: A flatback deformity is associated with the risk of an artificial perception post-THA, especially in patients with sarcopenia. PMI and PI-LL measurements may help predict THA outcomes.

Three-dimensional transfer of tibial tuberosity for patellar instability with patella alta preserves patellar position and clinical outcomes: A minimum 3-year follow-up study.

BACKGROUND: The three-dimensional (3D) transfer of tibial tuberosity has been reported to improve patellofemoral congruity and showed good clinical outcomes during the short follow-up, however, little is known about whether the patellar position and clinical outcomes are preserved at longer follow-ups and the risk factors for poor clinical outcomes. HYPOTHESIS: We hypothesized that patellar position and clinical outcomes would be preserved and the predisposing factors were associated with poor clinical outcomes after the 3D transfer of tibial tuberosity. PATIENTS AND METHODS: Thirty-nine patients, with a mean age of 27.9 (15-52) years, who underwent the 3D transfer of the tibial tuberosity were enrolled. Patellar position was evaluated using the Caton-Deschamps index and patellar tilt. Clinical outcomes were evaluated with Lysholm and Kujala scores pre- and postoperatively. Age, body mass index (BMI), radiographic measurements, and range of motion (ROM) were compared between the poor group (defined as <80 points on Kujala score) and the good group (≥80 points). The mean follow-up period was 54.1 (36-100) months. RESULTS: Patellar position decreased from 1.32 (1.21-1.53) preoperatively to 0.99 (0.84-1.07) at the final follow-up, according to the Caton-Deschamps index (p < 0.01). The mean patellar tilt decreased from 26.0° (21-40°) to 15.1° (5-28°) (p < 0.01). Kujala and Lysholm scales improved from 59.1 to 54.2 to 90.1 and 91.8 at final follow-up, respectively (p < 0.01). Increased BMI, lower femorotibial angle, limited ROM, and poor preoperative clinical outcomes were the predicting factors for poor postoperative clinical outcomes (p < 0.05). CONCLUSION: The 3D transfer for patellar instability with patella alta preserved the patellar position and clinical outcomes for at least 3 years. Predisposing factors that may potentially affect postoperative clinical outcomes of the 3D transfer of tibial tuberosity include an increased BMI, valgus knee, limited ROM, and poor preoperative clinical outcomes.

Unfavorable cortical hypertrophy potentially predisposes to periprosthetic "axe splitter" fracture in a collarless polished curved triple-tapered cemented stem: The time-dependent radiographic change in five SC-stem cases.

BACKGROUND: The periprosthetic fracture of cemented polished tapered stems is occasionally called a "unique" or "axe splitter" fracture. However, there has been insufficient evidence regarding the association between the radiographic findings prior to incidence and this cumbersome fracture. To determine if there are any radiographic interpretations associated with this fracture pattern, we report the five SC-stem cases with total hip arthroplasty. METHODS: We investigate the patient characteristics and serial radiographs of five fracture cases and evaluate the time-dependent specific radiographical changes around the stem between pre-arthroplasty and fracture. RESULTS: Fractures developed at 3.5-6.4 years after surgery with low-grade injury or with no particular incentive. Femoral cortical hypertrophy at the distal medial side around the stem was observed in all cases before the development of fractures, at 2-6 years after primary surgery. The duration between cortical hypertrophy appearance to the development of fracture was 0.4-3.1 years. CONCLUSIONS: The appearance of this zone-specific cortical hypertrophy might play a key role in the occurrence of periprosthetic fractures. Further studies with larger sample sizes should be conducted to elucidate this eccentric periprosthetic fracture.

Association of global sagittal spinal deformity with functional disability two years after total hip arthroplasty.

BACKGROUND: The relationship between spinopelvic alignment and functional disability after total hip arthroplasty (THA) has not been fully elucidated despite the growing recognition of its importance on patient-reported outcome measures. Therefore, our aim was to assess the effect of global sagittal spinal deformity on post-operative disability. METHODS: This analysis was based on 208 cases of THA, with functional disability measured at a follow-up of 2 years. The Hip Disability and Osteoarthritis Outcome Score-Joint Replacement (HOOS-JR), ranging from a scale of 0 (complete joint disability) to 100 (perfect joint health), was used to divide eligible patients into two groups, namely with and without disability, using a score of 70 as the cut-off. The following factors were compared between the two groups using multivariate analysis: age, sex, body height, body mass index, spinopelvic parameters, and surgeon experience. To identify the cut-off value of the parameters for predicting disability (HOOS-JR < 70/100), we used the receiver-operating characteristic curve. RESULTS: The disability (30 hips) and control (178 hips) groups showed a significant difference in pre-operative body height (p = 0.020), T1 pelvic angle divided by pelvic incidence (T1PA/PI; p = 0.018), PI minus lumbar lordosis (p = 0.027), post-operative HOOS-JR (p = 0.010), patient satisfaction (p = 0.033), and the modified Harris Hip Score (p = 0.038). On multivariate analysis, the following factors were associated with persistent disability: T1PA/PI > 0.2 (odds ratio [OR], 2.11; 95% confidence interval [CI], 1.19-4.14; p <  0.001) and height < 148 cm equivalent to legal standards as short stature (OR, 1.26; 95% CI, 1.09-1.48; p = 0.011). The cut-off value of pre-operative T1PA/PI was > 0.19, with a sensitivity of 95% and specificity of 85%. Post-operative satisfaction (p <  0.001), HOOS-JR (p = 0.023), and EuroQol 5-Dimension (p = 0.041) differed between the two groups when the pre-operative cut-off value was chosen as 0.2. CONCLUSIONS: A T1PA/PI > 0.2 was associated with greater disability after THA. Clinicians should be aware that patient-related factors, including global spinal deformities, particularly in patients with a short stature, can influence THA outcomes at 2 years postoperatively.

Preoperative factors associated with extension gap in cruciate-retaining total knee arthroplasty: A retrospective study on continuous determination of distraction force.

BACKGROUND: The aim of this retrospective study was to identify the preoperative patient-related factors affecting the soft tissue balancing in cruciate-retaining total knee arthroplasty. This is an important clinical issue, as the acquisition of adequate soft tissue balancing is essential for successful outcomes. METHODS: The study group included 59 knees treated for medial compartment osteoarthritis. The extension gap was measured using the newly electric tensor that enables continuous quantification of a distraction force ranging from 0 to 40 lbf. We performed regression analyses to identify the relationship between preoperative factors and the extension gap. RESULTS: Patient height, weight, and percent mechanical axis showed univariate correlation with the extension gap of either 30 lbf or 40 lbf. In the multivariate regression analysis without encountering multicollinearity, percent mechanical axis was inversely associated with the extension gap (t-value = -2.31, p = 0.02 for 30 lbf; and t-value = -2.39; p = 0.02 for 40lbf) as a significant independent factor. CONCLUSIONS: We revealed the significant influence of several factors on the absolute value of the extension gap. Particularly, the severity of preoperative coronal alignment was a statistically independent explanatory variable, and the extension gap was overvalued in knees with severe varus deformity. This influence should be considered when comparing different individual cases longitudinally. Our feasible strategies could lead to a better understanding about the soft tissue balancing in total knee arthroplasty.

Hyaluronic acid promotes proliferation and migration of human meniscus cells via a CD44-dependent mechanism.

PURPOSE: Treatment of meniscal injury is important for osteoarthritis (OA) prevention. Meniscus cells are divided between inner and outer cells, which have different characteristics and vascularity. We evaluated the effects of hyaluronic acid (HA) on the proliferation and migration of human inner and outer meniscus cells, and investigated the underlying healing mechanisms. MATERIALS AND METHODS: Lateral menisci from 18 patients who underwent total knee arthroplasty were used. Meniscus cells were harvested from the outer and inner menisci and evaluated using migration and proliferation assays after treatment with HA or chondroitin sulfate (CS). The effects of HA on prostaglandin E2 (PGE2)-induced apoptosis and gene expression were evaluated. RESULTS: Cell migration and proliferation were increased by HA in a concentration-dependent manner, in both inner and outer meniscus cells. PGE2-induced apoptosis and caspase-3/7 activity were suppressed by HA in both inner and outer meniscus cells, and these effects were blocked by an anti-CD44 antibody. COL2A1 and ACAN mRNA levels were upregulated following HA treatment of inner meniscus cells. MMP13 mRNA was downregulated following CS stimulation of both inner and outer meniscus cells. These results suggest that CS treatment suppresses the inflammatory reaction rather than providing meniscal restoration. The phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways were activated by HA in both types of meniscus cells; these effects were blocked by treatment with an anti-CD44 antibody. CONCLUSIONS: HA promoted human meniscus regeneration by inhibiting apoptosis, promoting cell migration, and accelerating cell proliferation, potentially through the PI3K/MAPK pathway via the CD44 receptor.

Hybrid high tibial osteotomy is superior to medial opening high tibial osteotomy for the treatment of varus knee with patellofemoral osteoarthritis.

PURPOSE: To evaluate patellofemoral congruity after opening wedge high tibial osteotomy (OWHTO) and hybrid HTO. METHODS: Twenty-four knees with hybrid HTO and 24 with OWHTO were evaluated in this study. The Caton-Deschamps and modified Miura-Kawamura indices were used to evaluate pre- and post-operative patellar heights for both types of surgery. Tibial tuberosity-trochlear groove (TT-TG) distance, patellar tilt, and medial and lateral joint space at the patellofemoral joint were compared. Anterior knee pain was assessed using the Kujala anterior knee pain scale. RESULTS: There was no significant difference between the correction angles of the hybrid HTO and OWHTO. Pre- and post-operative values for the Caton-Deschamps and modified Miura-Kawamura indices in patients who underwent hybrid HTO changed from 0.90 to 0.94 and from 0.95 to 1.03, respectively, with no significant differences noted. Following OWHTO, these values decreased significantly from 0.91 to 0.73 and from 1.06 to 0.84, respectively (p < 0.01). The post-operative patellar height after OWHTO was significantly lower than that after hybrid HTO (p < 0.01). After hybrid HTO, the TT-TG distance decreased significantly from 11.4 to 7.4 (p < 0.01), but it did not change significantly after OWHTO. Although pre- and post-operative patellar tilt were not altered significantly in either group, the medial joint space of the patellofemoral joint was significantly increased post-operatively following hybrid HTO (p = 0.035). The pre-operative Kujala scores were significantly lower in the hybrid HTO group, but post-operative scores improved in both groups. CONCLUSIONS: Hybrid HTO provides a better post-operative patellofemoral joint than does OWHTO with regard to patellar position and reduction of the TT-TG distance, as well as improved clinical outcomes. Hybrid HTO, rather than OWHTO, is the preferred technique for the treatment of varus knees combined with patellofemoral osteoarthritis. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

Sagittal Alignment of the Femoral Component and Patient Height Are Associated With Persisting Flexion Contracture After Primary Total Knee Arthroplasty.

BACKGROUND: The aim of our retrospective case-control study is to identify risk factors associated with a persisting flexion contracture after total knee arthroplasty (TKA). This is an important clinical issue as a flexion contraction can lead to poor long-term clinical outcomes and patient satisfaction after TKA. METHODS: The study group included 120 knees treated for a varus osteoarthritic deformity of the knee using a posterior cruciate-retaining TKA. We evaluated the association between a flexion contracture >10°, 2 years after surgery, and the following potential risk factors, using logistic regression analysis: age, body height, body mass index, preoperative knee extension and hip-knee-ankle angle, and radiological parameters of component alignment, namely the femoral component medial angle, the femoral component flexion angle (FFA), the tibial component medial angle, and the posterior tibial slope. RESULTS: Of the 120 knees, a persisting flexion contracture >10° was identified in 33 (28%). The mean FFA in these cases was 7.3° (standard deviation, 1.4) compared to 4.2° (standard deviation, 1.2) for cases with a contracture of ≤10° (P = .034). On multivariate analysis, the FFA (odds ratio, 3.73; 95% confidence interval, 1.16-17.81; P = .034) and body height (odds ratio, 0.43; 95% confidence interval, 0.29-0.57; P = .041) were independent predictive risk factors for a residual flexion contracture >10°. CONCLUSION: Clinicians should be aware that flexed position of the femoral component, particularly in patients of short stature, is associated with increased occurrence of persistent flexion contracture.

Medial meniscal extrusion and spontaneous osteonecrosis of the knee.

PURPOSE: Causes of spontaneous osteonecrosis of the knee (SONK) have not been clearly elucidated. This study investigated the relationship between medial meniscal extrusion and SONK. METHODS: We reviewed 108 SONK knees and determined their Aglietti stage. Meniscal extrusion is defined when it extends beyond the medial margin of tibial plateau and osteophytes are excluded for determining the margin. Both absolute extrusion (AE) and relative percentage of extrusion (RPE) were measured, and meniscal tear patterns were evaluated in the early stages of SONK (I and II). RESULTS: All knees had meniscal extrusion. Stage I was detected in 39 knees; II, in 23; III, in 16; IV, in 18; and V, in 12. The mean AE and RPE were 4.2 mm and 42% in stage I, 5.0 mm and 52% in stage II, 6.8 mm and 71% in stage III, 7.0 mm and 69% in stage IV, and 7.8 mm and 80% in stage V, respectively. The knees in the early stages showed less AE and RPE than those in late stages IV (p < 0.05) and V (p < 0.01). Additionally, the level of AE (ρ = 0.63, p < 0.0001) and RPE (ρ = 0.58, p < 0.0001) correlated with the SONK stage. Of knees with early-stage SONK, 12 knees had no tear, 26 had horizontal tears, 1 had longitudinal tear, 6 had degenerative tears, 2 had radial tears, 1 had complex tear, and 14 had root tears. Neither AE nor RPE differed significantly among tear patterns. CONCLUSIONS: Meniscal extrusion was recognized even in early stages, with a significant correlation between the SONK stage and extrusion. Although the most frequent tear pattern in early-stage SONK was horizontal tear, 12 knees had meniscal extrusion with no tears. Therefore, meniscal extrusion, which indicates meniscal dysfunction, may be a cause of SONK and be related with the developmental stage of SONK.

MicroRNA-140 plays dual roles in both cartilage development and homeostasis.

Osteoarthritis (OA), the most prevalent aging-related joint disease, is characterized by insufficient extracellular matrix synthesis and articular cartilage degradation, mediated by several proteinases, including Adamts-5. miR-140 is one of a very limited number of noncoding microRNAs (miRNAs) specifically expressed in cartilage; however, its role in development and/or tissue maintenance is largely uncharacterized. To examine miR-140 function in tissue development and homeostasis, we generated a mouse line through a targeted deletion of miR-140. miR-140(-/-) mice manifested a mild skeletal phenotype with a short stature, although the structure of the articular joint cartilage appeared grossly normal in 1-mo-old miR-140(-/-) mice. Interestingly, miR-140(-/-) mice showed age-related OA-like changes characterized by proteoglycan loss and fibrillation of articular cartilage. Conversely, transgenic (TG) mice overexpressing miR-140 in cartilage were resistant to antigen-induced arthritis. OA-like changes in miR-140-deficient mice can be attributed, in part, to elevated Adamts-5 expression, regulated directly by miR-140. We show that miR-140 regulates cartilage development and homeostasis, and its loss contributes to the development of age-related OA-like changes.

Clinical usefulness of hindfoot assessment for total knee arthroplasty: persistent post-operative hindfoot pain and alignment in pre-existing severe knee deformity.

PURPOSE: The purpose of this study was to compare the hindfoot alignment and symptoms in patients with pre-existing moderate and severe knee deformities after total knee arthroplasty (TKA). METHODS: Eighty knees of 75 patients who underwent TKA for varus osteoarthritis were enrolled retrospectively and evaluated the following pre-operatively and at 2 years post-operatively: the American Orthopaedic Foot and Ankle Society ankle-hindfoot scale (pain and function scores), calcaneal pitch, and naviculocuboid overlap as an indicator of hindfoot alignment. The knees were divided into two groups according to the pre-operative hip-knee-ankle angle defined as the angle between the mechanical axis of the femur and the tibia: group M with genu varus of ≤6°, and group S with varus >6°. RESULTS: The pain (p = 0.03) and function (p = 0.02) scores improved in group M; however, in group S, these measures did not change. The differences between the groups were not significant concerning the pre-operative calcaneal pitch and naviculocuboid overlap. The post-operative pitch (p = 0.03) and the overlap (p = 0.04) in group M was significantly greater and less than those in group S, respectively. Although the pitch (p < 0.01) and the overlap (p = 0.03) increased in group M, these did not change in group S. Post-operative hindfoot pain and valgus remained in patients in group S. CONCLUSIONS: For pre-existing moderate knee deformities, a relationship was observed between post-operative knee alignment and compensatory hindfoot alignment, whereas patients with severe deformities experienced persistent post-operative hindfoot pain and valgus alignment. It was concluded that evaluations and managements of residual symptoms after TKA including the hindfoot are important. These findings are clinically relevant that perioperative evaluation of the hindfoot should be required in knee surgery. To help improve the outcomes of TKA, clinicians may consider perioperative intervention in the insole and/or physical therapy of the foot and ankle. LEVEL OF EVIDENCE: Therapeutic study, Level III.

Influence of age on clinical outcomes of three-dimensional transfer of the tibial tuberosity for patellar instability with patella alta.

PURPOSE: To evaluate the clinical outcomes of three-dimensional (3D) transfer of the tibial tuberosity for patellar instability with patella alta, with a focus on the influence of age at initial surgery. METHODS: Three-dimensional surgery was performed on 28 knees with a mean follow-up of 46 months. Patients were separated into three groups based on the age at initial surgery: group A, 10 knees and an average age of 16.3 ± 1.8 (14-19) years; group B, 10 knees and an average age of 22.1 ± 2.5 (20-28) years; and group C, eight knees and an average age of 44.0 ± 2.2 (40-46) years. Patellofemoral geometry improvement focused on patella alta by determining the Insall-Salvati ratio and Caton-Deschamps index, rotational malalignment by measuring the tibial tubercle-trochlear groove (TT-TG) distance, and lateral patellar subluxation by measuring the patellar tilt. Clinical outcomes were evaluated by the Lysholm and Kujala scores, which were compared before and after surgery. Cartilage degeneration was evaluated by the International Cartilage Repair Society grading system at initial arthroscopy. RESULTS: The patellar height, TT-TG, and patellar tilt significantly improved in all groups postoperatively (p < 0.05). The Lysholm and Kujala scores also significantly improved postoperatively; however, both scores were lower in group C than in the other groups (p < 0.05). Particularly, pain scores were more severe in group C than in the other groups, and the severity of cartilage degeneration correlated with the pain scores (p < 0.05). Cartilage damage differed significantly between the groups at initial arthroscopy; particularly, group C included grades III and IV cartilage degeneration (p < 0.05). CONCLUSIONS: Age at initial surgery may be the predicting factor for poor clinical outcomes of 3D transfer surgery. The clinical outcome may depend on the age at surgery, which correlated with cartilage damage; thus, surgeons should be given this information when patients are considered undergoing patella surgery. LEVEL OF EVIDENCE: Therapeutic case series, Level IV.

Correlation between varus knee malalignment and patellofemoral osteoarthritis.

PURPOSE: To evaluate the relationship between patellofemoral osteoarthritis (OA) and varus OA of the knee with a focus on the location of joint space narrowing. METHODS: Eighty-five patients scheduled to undergo total knee arthroplasty caused by varus OA were enrolled in this study. The relationship between patellofemoral OA and varus knee malalignment was elucidated. To determine the alignment of the patellofemoral joint in varus knees, patellar tilt, and the tibial tuberosity-trochlear groove (TT-TG) distance were measured, and patellofemoral OA was classified using computed tomography. RESULTS: The femorotibial angles in patients with stage II-IV patellofemoral OA were significantly larger than those in patients with stage I patellofemoral OA, and the patellar tilt in patients with stage II-IV patellofemoral OA and the TT-TG distance in patients with stage IV patellofemoral OA were significantly larger than those in patients with stage I patellofemoral OA. The TT-TG distance was strongly correlated with patellar tilt (R(2) = 0.41, P < 0.001). Patellofemoral joint space narrowing was mainly noted at the lateral facet, and it was found on both sides as patellofemoral OA worsened. CONCLUSION: Varus knee malalignment was induced by patellofemoral OA, especially at the lateral facet. Patellar tilt and the TT-TG distance are considered critical factors for the severity of patellofemoral OA. Understanding the critical factors for patellofemoral OA in varus knees such as the TT-TG distance and patellar will facilitate the prevention of patellofemoral OA using procedures such as high tibial osteotomy and total knee arthroplasty to correct knee malalignment. LEVEL OF EVIDENCE: Retrospective cohort study, Level III.