The mediation effects of malalignment on the relation of sex to the risk of incidence tibiofemoral osteoarthritis.

OBJECTIVE: To investigate to what extent the higher risk of tibiofemoral radiographic osteoarthritis (TFROA) in females vs. males can be explained by knee malalignment. DESIGN: Using data from Multicenter Osteoarthritis Study (MOST) and Osteoarthritis Initiative (OAI), we examined the relation of sex to the incident medial and lateral TFROA and performed mediation analyses to assess to what extent varus and valgus malalignments account for sex differences in the incident medial or lateral TFROA. RESULTS: Of the 3462 knees without medial and lateral TFROA in MOST, the 7-year risks of medial and lateral TFROA were 16.9% and 10.0% in females, and 15.8% and 4.2% in males, respectively. Females had 2.31-fold (95% confidence interval [95% CI]: 1.73 to 3.08) higher incident lateral TFROA than males, and the relative risk (RR) of the indirect effect of sex on lateral TFROA through valgus malalignment was 1.15 (95% CI: 1.09 to 1.20), accounting for 23% of its total effect on lateral TFROA. In OAI (n = 3095 knees), females had 1.54-fold (95% CI: 1.15 to 2.04) higher incident lateral TFROA than males, and RR of the indirect effect of sex on lateral TFROA through valgus malalignment was 1.10 (95% CI: 1.04 to 1.21), accounting for 26% of its total effect on lateral TFROA. No apparent sex difference in the incident medial TFROA was found in MOST (RR = 1.05, 95% CI: 0.89 to 1.25) or OAI (RR = 1.02, 95% CI: 0.84 to 1.19). CONCLUSION: Females had a higher risk of developing lateral TFROA than males; however, valgus malalignment only modestly explained such a difference.

Risk factor heterogeneity for medial and lateral compartment knee osteoarthritis: analysis of two prospective cohorts.

OBJECTIVE: To evaluate the etiologic heterogeneity between medial and lateral tibiofemoral radiographic osteoarthritis (ROA). METHODS: Knees without medial or lateral tibiofemoral ROA at baseline were followed for 60-month in Multicenter Osteoarthritis Study (MOST) and for 48-month in Osteoarthritis Initiative (OAI). We examined the relation of previously reported risk factors to incident medial and lateral tibiofemoral ROA separately and determined the etiology heterogeneity with a ratio of rate ratios (RRs) (i.e., the RR for medial tibiofemoral ROA divided by the RR for lateral tibiofemoral ROA) using a duplication method for Cox proportional hazard regression. RESULTS: Of 2,016 participants in MOST, 436 and 162 knees developed medial or lateral tibiofemoral ROA, respectively. Obesity and varus malalignment were 95% and 466% more strongly associated with incident medial tibiofemoral ROA than with lateral tibiofemoral ROA, respectively (ratios of RRs, 1.95 [95% confidence interval (CI):1.05-3.62] and 5.66 [95% CI:3.20-10.0]). In contrast, the associations of female sex and valgus malalignment with incident medial tibiofemoral ROA were weaker or in an opposite direction compared with lateral tibiofemoral Osteoarthritis (OA) (ratios of RRs, 0.40 [95% CI:0.26-0.63] and 0.20 [95% CI:0.12-0.34], respectively). Older age tended to show a weaker association with incident medial tibiofemoral ROA than with incident lateral tibiofemoral ROA. No heterogeneity was observed for the relation of race, knee injury, or contralateral knee ROA. These findings were closely replicated in OAI. CONCLUSION: Risk factor profiles for medial and lateral tibiofemoral ROA are different. These results can provide a framework for the development of targeted prevention and potential treatment strategies for specific knee OA subtypes.

Do femoral fractures in adult patients with osteogenesis imperfecta imitate atypical femoral fractures? A case series.

Atypical femoral fractures (AFFs) are low-energy femoral fractures with characteristic radiological features and a suspected relation to treatment with bisphosphonate (BP) or denosumab. In osteogenesis imperfecta (OI), BP is currently the drug of choice when medical treatment is indicated. Due to bone deformities, the radiologic appearance of femoral fractures may be different in patients with OI and patients with osteoporosis. We investigated the prevalence and appearance of femoral fractures in a cohort of adult patients with confirmed OI (55 patients, age range 19-69 years, 26 women (47%) and 35 patients (64%) had received BP treatment), who attended the outpatient clinic at Aarhus University Hospital. The fractures were evaluated according to major and minor AFF criteria. In our OI cohort, we found that eight out of 55 patients had suffered a femoral fracture in adult year: five women and three men, aged 25 to 54 years. One patient had OI type I, two had OI type III, four had OI type IV, and one had OI type V. All fractures were associated with no or minimal trauma. Four patients had fractures that fulfilled the criteria of AFFs. Two of the four patients had received long-term BP treatment prior to the fracture and three patients had severe deformities of the femur. Femoral fractures in OI imitate AFFs. This suggests that bone deformity, collagen deficiencies, and alterations in mineralization of bone may cause femoral fractures that imitate AFFs even in the absence of antiresorptive treatment. Bone deformities should be monitored as part of the management of adult patients with OI. Continuous dull or aching pain in the groin or thigh should lead to radiographic examination. The radiologic appearance of femoral fractures may be different in patients with osteogenesis imperfecta (OI) and patients with osteoporosis, thus imitate atypical femoral fractures (AFF). We found that bone deformity, collagen deficiencies, and alterations in bone mineralization may cause femoral fractures that imitate AFFs even in the absence of antiresorptive treatment.

The Natural History of Lower Extremity Malalignment.

BACKGROUND: Lower extremity malalignment is a common problem presented to pediatric orthopaedists. Risk for early arthritis is often a concern among parents seeking advice and treatment. We seek to review previous research with regard to the natural history of malalignment. METHODS: A search of available literature on PubMed was constructed to capture articles covering the natural history of malalignment, secondary to childhood fracture as well as congenital and acquired pediatric deformity. In order to remain strictly relevant to pediatrics, articles reviewing deformities acquired in adulthood were not referenced. Biomechanical data and animal studies were included when deemed appropriate. RESULTS: High-quality data with regard to long-term risk of arthritis due to malalignment is lacking. Through a combination of biomechanical data, animal models, and a small body of longitudinal clinical data, it is clear that some patients with malalignment progress to early arthritic change. Unfortunately, detailed risk factors of who is at high risk versus low risk remains difficult to determine. CONCLUSIONS: Treatment of minor lower extremity malalignment is not supported by the current orthopaedic literature. Treatment plans should focus on the presence of symptoms, and in asymptomatic but severe cases. Even in more severe cases, strong evidence to support prophylactic realignment is not available. Evidence to suggest that preventative realignment is superior to intervention at the time of symptom onset does not exist.

Primary Versus Revision Anterior Cruciate Ligament Reconstruction: Patient Demographics, Radiographic Findings, and Associated Lesions.

PURPOSE: The purpose of this study was to evaluate the differences in intra-articular pathology, demographic characteristics, and radiographic characteristics of the knee associated with primary anterior cruciate ligament reconstruction (ACLR) versus revision ACLR at the time of initial presentation with either a native anterior cruciate ligament tear or an anterior cruciate ligament graft tear. Secondarily, we aimed to investigate risk factors for concomitant medial and lateral meniscal tears and cartilage injuries at the time of ACLR. METHODS: This was a retrospective review of patients who underwent primary or revision ACLR by a single surgeon. The exclusion criteria were as follows: skeletally immature patients; patients with an intra-articular fracture; patients with an ipsilateral knee infection; or patients who underwent an osteotomy, cartilage restoration procedure, or meniscal transplantation either previously or concomitantly with the ACLR. Detailed patient demographic data, radiographic long-standing alignment, tibial slope, and intraoperative findings including articular cartilage injury grade and meniscus integrity were documented at surgery. RESULTS: There were 487 patients included in this study (363 with primary ACLR and 124 with revision ACLR). There were no significant differences in age (P = .119), sex (P = .917), body mass index (P = .468), allograft versus autograft reconstruction (P = .916), or prevalence of meniscal tears (P = .142) between the primary and revision groups. Patients who underwent revision ACLR had a significantly increased medial tibial slope (P = .048) and a higher prevalence of chondral defects on both the medial (P < .001) and lateral (P = .003) femoral condyles when compared with primary ACLR patients. Logistic regression showed that a decreased tibial slope was correlated with femoral medial-sided chondral injuries and that varus or valgus coronal-plane malalignment was correlated with lateral meniscal tears in both groups. CONCLUSIONS: The findings of this study show that patients undergoing a revision ACLR have significantly more chondral lesions, as well as higher-grade chondral lesions, at the time of presentation. Furthermore, coronal malalignment and a decreased tibial slope may contribute to injury patterns of the lateral meniscus and medial compartment cartilage, respectively. LEVEL OF EVIDENCE: Level III, retrospective case-control study.

Association Between Knee Malalignment and Ankle Degeneration in Patients With End-Stage Knee Osteoarthritis.

BACKGROUND: The association between knee malalignment and ankle degeneration has not been well established. This study aimed at determining whether knee malalignment and compensatory ankle morphology to knee malalignment are associated with the development and progression of ankle osteoarthritis (OA) in patients with end-stage knee OA. METHODS: We retrospectively reviewed 96 patients (106 knees) who underwent total knee arthroplasty. The progression of ankle OA, knee alignment, and ankle morphology were evaluated based on digital radiographs. Alignment deformity of the lower extremity was evaluated with hip-knee-ankle angle and medial proximal tibial angle (MPTA). Ankle morphology was evaluated by the lateral distal tibial angle, talar tilt, tibial plafond inclination angle, and ankle joint line orientation angle. RESULTS: The incidence of radiological ankle OA was observed in 39 of 106 cases. The MPTA (odds ratio = 0.72, P = .0009) and hip-knee-ankle angle (odds ratio = 1.13, P = .0169) were significantly associated with ankle OA. Among patients with tibial varus deformity, 26 of 49 had ankle OA. Among patients with neutral tibial alignment, 13 of 57 had radiological findings of ankle OA. MPTA was the only parameter associated with the progression of ankle OA. No association was observed between compensatory change in ankle morphology and the severity of ankle OA. CONCLUSION: Tibial varus deformity is associated with the development and progression of ankle OA; however, it is unclear whether it causes ankle OA. Due to the high incidence of ankle OA in total knee arthroplasty patients, it is reasonable to consider routine evaluation of the ankle.

The Nonsurgical Management of Orbital Dystopia Using Refractive Lenses and Prosthetic Shells.

Surgical rehabilitation of orbital dystopia can be challenging. The authors demonstrate the effective use of spectacle lenses to visually correct misalignments of the globe and the orbit. Presented is a retrospective review of 4 patients undergoing aesthetic rehabilitation through use of spectacle lenses and in a number patients a cosmetic shell.Two patients with neurofibromatosis presented with inferior dystopia of the globe and orbit. A base-down prismatic lens applied to the spectacles in conjunction with a prosthetic shell successfully visually corrected the facial asymmetry and improved patients' aesthetic appearance. One patient with a history of traumatic retinal detachment, who did not want any surgical intervention, a "plus" (hypermetropic) lens was used to magnify the perceived image of an enophthalmic and phthisical globe, to enhance appearance and improve symmetry. In the fourth patient, with Goldenhar syndrome, the appearance of a hypotropia and concurrent esotropia was successfully treated with a Fresnel prism and a prosthetic shell.This case series illustrates the successful role of various refractive lenses often in conjunction with prosthetic shells in patients with reduced vision and orbital dystopia to improve facial symmetry. This conservative treatment is especially useful when surgery is not a desired or not considered a suitable option for the patient.

Changes in Rearfoot Alignment in Chronic Plantar Heel Pain.

Plantar heel pain is a common disabling condition in adults. Biomechanical factors are important in the development of plantar heel pain. Quantitative changes in rearfoot alignment in patients with plantar heel pain have not been previously investigated. From April 2016 to March 2017, 100 patients with plantar heel pain and 100 healthy individuals were recruited. The foot posture index was used for the measurement of foot alignment. The generalized joint hypermobility condition was assessed using the Beighton scale. The transverse plane talocalcaneal angle, calcaneocuboid angle, talonavicular uncovering angle, calcaneal inclination angle (CIA), talar declination angle, talar-first metatarsal angle, and sagittal talocalcaneal angle were measured on standard weightbearing anteroposterior and lateral foot radiographs. The body mass index was recorded electronically. The distribution of sex, age, weight, body mass index, side, foot posture index score, and Beighton scale were comparable between groups (p > .05). The mean calcaneocuboid angle (p = .009), talonavicular uncovering angle (p = .000), CIA (p = .000), talar declination angle (p = .039), and talar-first metatarsal angle (p = .000) were significantly higher in the plantar heel pain group. In conclusion, our study has demonstrated a relationship between chronic plantar heel pain and the CIA.

Changes in biomechanical risk factors for knee osteoarthritis and their association with 5-year clinically important improvement after limb realignment surgery.

OBJECTIVE: To evaluate 5-year outcomes after lower limb realignment and test the hypothesis that surgery-induced changes in selected biomechanical risk factors for medial knee osteoarthritis (OA) are associated with clinically important improvements. DESIGN: We prospectively evaluated patient-reported outcomes, full-limb standing radiographs and gait biomechanics before, 6 months (surgery-induced change) and 5 years after medial opening wedge high tibial osteotomy (HTO) in 170 patients (46.4 ± 8.9 years, 135 males) with knee OA and varus alignment. Logistic regression tested the associations of 6-month changes in mechanical axis angle and knee adduction moment with achieving an increase of ≥10 points in the Knee injury and Osteoarthritis Outcome Score (KOOS)4 at 5 years, with and without adjusting for covariates. Gait data were also compared to existing data from healthy controls. RESULTS: Mean 5-year changes (95% confidence interval (CI)) were: KOOS4: +14.2 (10.8, 17.6); mechanical axis angle: +8.21° (7.58, 8.83); knee adduction moment: -1.49 %BW*Ht (-1.35, -1.63). The postoperative knee adduction moments were typically lower than values for healthy controls. When divided into quartiles, although all strata improved significantly, patients with reductions in knee adduction moment of 1.14-1.74 %BW*Ht (neither largest nor smallest changes) had highest 5-year KOOS4 scores. The 6-month change in knee adduction moment (odds ratios (OR) = 0.38; 95% CI: 0.22, 0.67), preoperative KOOS4 (OR = 0.96; 95% CI: 0.94, 0.99) and preoperative medial tibiofemoral narrowing grade (OR = 0.62; 95% CI: 0.37, 1.00) were negatively associated with having a 5-year clinically important improvement (C-statistic = 0.70). CONCLUSIONS: Substantial improvements in biomechanical risk factors and patient-reported outcomes are observed 5 years after medial opening wedge HTO. The surgery-induced change in load distribution during walking is significantly associated with long-term clinically important improvement.

Knee internal contact force in a varus malaligned phenotype in knee osteoarthritis (KOA).

PURPOSE: Multiple phenotypes characterized by different disease mechanisms have been hypothesized to explain the large variability in the knee osteoarthritis (KOA) population. The purpose of this study was: to estimate and compare the medial and lateral knee compression forces (CF) during gait of three subgroups of KOA subjects characterized by different alignment and cartilage disruption patterns. METHODS: A secondary data analysis was conducted on a sample of 39 KOA subjects and 18 controls (C). The patients were classified in the different groups according to the following criteria: Varus medial disease (VMD) (12): varus alignment and predominant medial cartilage degeneration Varus generalized disease (VGD) (17): varus alignment and cartilage degeneration that extends to the lateral compartment. Neutral alignment (NA) (10): neutral alignment. The total, medial and lateral CF corrected for body weight were estimated using an inverse dynamics model (AnyBody Modeling System, AnyBody Technology) during stance. RESULTS: The impulse of the medial compressive force (MCF) (overall effect of the CF over the stance) was significantly higher (P < 0.01) in the VMD compared to all the other groups. Peak MCF was higher in the VMD compared to all the other groups, but the difference reached significance only when compared to the VGD group (P < 0.05). The results of the regression analysis showed a significant relationship in the VMD group between alignment and impulse of the MCF (R2 = 0.62; P < 0.01). This relationship disappears in the other groups. CONCLUSIONS: These findings suggest the existence of a phenotype characterized by increased MCF.

Patellofemoral morphology and alignment: reference values and dose-response patterns for the relation to MRI features of patellofemoral osteoarthritis.

OBJECTIVE: We aimed to (1) determine reference values for trochlear morphology and patellofemoral (PF) alignment in adults without magnetic resonance imaging (MRI)-defined PF full thickness cartilage damage or knee pain; and (2) evaluate dose-response patterns for these measures with prevalent MRI-defined PF structural damage and/or knee pain. DESIGN: The Framingham Community Cohort is a population-based sample of ambulatory adults aged ≥50 years. We evaluated six morphology and alignment measures using MRI (n = 985), and reported reference values (mean ± 2SD) in a subsample without MRI-defined PF full thickness cartilage damage or knee pain (n = 563). With restricted cubic spline Poisson regression, we evaluated dose-response patterns of each of the six measures with prevalent MRI-defined PF structural damage or joint pain. Our primary outcome was full thickness cartilage damage. RESULTS: For dose-response curves, prevalence ratios (PR) increased monotonically for all measures except patellar tilt, which rose with both lateral and medial tilt. Associations were generally strongest in the lateral PF compartment. PR for the strongest predictors of full thickness cartilage damage reached clinical relevance (PR > 1.5) at sulcus angle (SA) ≥135.0°; patellar tilt angle at ≤1.0° and ≥15.0°; and bisect offset ≥57.0%. Lateral trochlear inclination (LTI) achieved PR > 1.5 at ≤23.0° for full thickness cartilage damage with pain. CONCLUSIONS: SA, patellar tilt, and bisect offset were most strongly associated with full thickness cartilage damage. LTI, patellar tilt and bisect offset had stronger associations with the addition of pain. These findings contribute to better identifying a subset of patients who may benefit from mechanically based interventions.

Measurement of Femoral Version by MRI is as Reliable and Reproducible as CT in Children and Adolescents With Hip Disorders.

BACKGROUND: Femoral version measurement techniques based on magnetic resonance imaging (MRI) studies have been developed as an alternative to the high levels of ionizing radiation associated with computed tomography (CT)-based methods. Previous studies have not evaluated the reliability, repeatability, and accuracy of MRI-based femoral version measurements in an adolescent population. METHODS: Subjects who underwent MRI and CT studies for clinical suspicion of hip pain secondary to hip dysplasia or femoroacetabular impingement between 2011 and 2013 were identified. Rapid sequence femoral version images were obtained from MRI Hip dGEMRIC and/or postarthrogram studies. Femoral version images were also obtained from bilateral CT lower extremity, without contrast, studies. Measurements were made by 1 fellowship-trained, pediatric hip preservation attending surgeon, 2 pediatric orthopaedic surgical fellows, and 1 fellowship-trained musculoskeletal radiologist on 2 separate occasions. Linear mixed models were used to estimate the reliability and repeatability associated with CT-based and MRI-based measurements (intraclass correlation coefficients) and to estimate the agreement (CT-MRI) between the 2 techniques. RESULTS: The mean age of 36 subjects was 15.4 years (±4.1 y). Interrater reliability was 0.91 (95% CI, 0.86-0.95) for the CT technique compared with 0.90 (95% CI, 0.86-0.94) for the rapid sequence MRI technique. Intrarater reliability for the CT technique was 0.96 (95% CI, 0.91-0.98) compared with 0.95 (95% CI, 0.90-0.97) for the MRI technique. The agreement between the MRI-based and CT-based techniques (bias: 1.9 degrees, limits of agreement: -11.3 to 14.9 degrees) was similar to the agreement between consecutive MRI measurements (bias: 0.4 degrees, limits of agreement: -7.8 to 8.6 degrees) as well as consecutive CT measurements (bias: 0.5 degrees, limits of agreement: -8.8 to 9.9 degrees). CONCLUSIONS: The interrater and intrarater reliability and repeatability estimates (intraclass correlation coefficient values) associated with both techniques was excellent (>0.90). Acquirement of axial images at the pelvis and knee during MRI for investigation of adolescents with hip pain allows for reliable measurement of femoral version. LEVEL OF EVIDENCE: Level II-diagnostic study.

Risk factors for meniscal body extrusion on MRI in subjects free of radiographic knee osteoarthritis: longitudinal data from the Osteoarthritis Initiative.

OBJECTIVE: To determine risk factors associated with increased meniscal body extrusion on knee magnetic resonance (MR) images in subjects free of radiographic osteoarthritis (OA). METHODS: We selected 340 subjects (aged 45-55 years, mean [SD] body mass index 26.7 [4.4], 51% women) with Kellgren-Lawrence grade 0 in both knees and bilateral knee MR images available at the baseline, 24 months, 48 months, and 72 month exam from the Osteoarthritis Initiative (OAI). We assessed mid-coronal 3-T MR images from baseline through the 72-month exam. One observer measured widths of the tibia plateau and medial or lateral meniscal body extrusion for baseline and 72 months follow-up. Another observer assessed meniscal integrity at all four time points. We calculated an extrusion ratio ([meniscal body extrusion]/[tibia width] × 100) to account for knee size. We evaluated risk factors for increased meniscal body extrusion ratio from baseline to 72 months by a multivariable linear regression mixed model for medial and lateral compartment, respectively. RESULTS: In the medial compartment female sex (ß = 0.35; 95% confidence interval [CI] 0.16-0.53), incident meniscal tear (ß = 0.29; 95% CI 0.22-0.55), and the baseline value of the extrusion ratio (ß = 0.63; 95% CI 0.56-0.70) were associated with increased extrusion ratio by 72 months. Results were similar for the lateral compartment. CONCLUSIONS: Only female sex, incident meniscal tear, and higher baseline value of extrusion are risk factors for increased meniscal body extrusion in subjects free of radiographic OA. The results suggest that meniscal extrusion may contribute to and mediate the well-known increase in knee OA incidence in middle-aged women.

A comparison of radiographic anatomic axis knee alignment measurements and cross-sectional associations with knee osteoarthritis.

OBJECTIVE: Malalignment is associated with knee osteoarthritis (KOA), however, the optimal anatomic axis (AA) knee alignment measurement on a standard limb radiograph (SLR) is unknown. This study compares one-point (1P) and two-point (2P) AA methods using three knee joint centre locations and examines cross-sectional associations with symptomatic radiographic knee osteoarthritis (SRKOA), radiographic knee osteoarthritis (RKOA) and knee pain. METHODS: AA alignment was measured six different ways using the KneeMorf software on 1058 SLRs from 584 women in the Chingford Study. Cross-sectional associations with principal outcome SRKOA combined with greatest reproducibility determined the optimal 1P and 2P AA method. Appropriate varus/neutral/valgus alignment categories were established using logistic regression with generalised estimating equation models fitted with restricted cubic spline function. RESULTS: The tibial plateau centre displayed greatest reproducibility and associations with SRKOA. As mean 1P and 2P values differed by >2°, new alignment categories were generated for 1P: varus <178°, neutral 178-182°, valgus >182° and for 2P methods: varus <180°, neutral 180-185°, valgus >185°. Varus vs neutral alignment was associated with a near 2-fold increase in SRKOA and RKOA, and valgus vs neutral for RKOA using 2P method. Nonsignificant associations were seen for 1P method for SRKOA, RKOA and knee pain. CONCLUSIONS: AA alignment was associated with SRKOA and the tibial plateau centre had the strongest association. Differences in AA alignment when 1P vs 2P methods were compared indicated bespoke alignment categories were necessary. Further replication and validation with mechanical axis alignment comparison is required.

Coronal tibial slope is associated with accelerated knee osteoarthritis: data from the Osteoarthritis Initiative.

BACKGROUND: Accelerated knee osteoarthritis may be a unique subset of knee osteoarthritis, which is associated with greater knee pain and disability. Identifying risk factors for accelerated knee osteoarthritis is vital to recognizing people who will develop accelerated knee osteoarthritis and initiating early interventions. The geometry of an articular surface (e.g., coronal tibial slope), which is a determinant of altered joint biomechanics, may be an important risk factor for incident accelerated knee osteoarthritis. We aimed to determine if baseline coronal tibial slope is associated with incident accelerated knee osteoarthritis or common knee osteoarthritis. METHODS: We conducted a case-control study using data and images from baseline and the first 4 years of follow-up in the Osteoarthritis Initiative. We included three groups: 1) individuals with incident accelerated knee osteoarthritis, 2) individuals with common knee osteoarthritis progression, and 3) a control group with no knee osteoarthritis at any time. We did 1:1:1 matching for the 3 groups based on sex. Weight-bearing, fixed flexion posterior-anterior knee radiographs were obtained at each visit. One reader manually measured baseline coronal tibial slope on the radiographs. Baseline femorotibial angle was measured on the radiographs using a semi-automated program. To assess the relationship between slope (predictor) and incident accelerated knee osteoarthritis or common knee osteoarthritis (outcomes) compared with no knee osteoarthritis (reference outcome), we performed multinomial logistic regression analyses adjusted for sex. RESULTS: The mean baseline slope for incident accelerated knee osteoarthritis, common knee osteoarthritis, and no knee osteoarthritis were 3.1(2.0), 2.7(2.1), and 2.6(1.9); respectively. A greater slope was associated with an increased risk of incident accelerated knee osteoarthritis (OR = 1.15 per degree, 95 % CI = 1.01 to 1.32) but not common knee osteoarthritis (OR = 1.04, 95 % CI = 0.91 to 1.19). These findings were similar when adjusted for recent injury. Among knees with varus malalignment a greater slope increases the odds of incident accelerated knee osteoarthritis; there is no significant relationship between slope and incident accelerated knee osteoarthritis among knees with normal alignment. CONCLUSIONS: Coronal tibial slope, particularly among knees with malalignment, may be an important risk factor for incident accelerated knee osteoarthritis.

Biomechanical considerations in the pathogenesis of osteoarthritis of the elbow.

Osteoarthritis is the most common joint disease and a major cause of disability. Distinct biological processes are considered crucial for the development of osteoarthritis and are assumed to act in concert with additional risk factors to induce expression of the disease. In the classical weightbearing joints, one such risk factor is an unfavourable biomechanical environment about the joint. While the elbow has long been considered a non-weightbearing joint, it is now assumed that the tissues of the upper extremity may be stressed to similar levels as those of the lower limb, and that forces across the elbow are in fact very high when the joint is extended from a flexed position. This review examined the available basic science, preclinical and clinical evidence regarding the role of several unfavourable biomechanical conditions about the elbow on the development of osteoarthritis: post-traumatic changes, osteochondritis dissecans, instability or laxity and malalignment. Post-traumatic osteoarthritis following fractures is well recognized, however, the role of overload or repetitive microtrauma as risk factors for post-traumatic osteoarthritis is unclear. The natural course of untreated cartilage defects in general, and osteochondritis dissecans at the elbow in particular, remains incompletely understood to date. However, larger lesions and older age seem to be associated with more symptoms and radiographic changes in the long term. Instability seems to play a role, although the association between instability and osteoarthritis is not yet clearly defined. No data are available on the association of malalignment and osteoarthritis, but based on force estimations across the elbow joint, it seems reasonable to assume an association.

Can young and active patients participate in sports after osteochondral autologous transfer combined with valgus high tibial osteotomy?

PURPOSE: To evaluate sporting activity following osteochondral autologous transfer (OAT) combined with valgus high tibial osteotomy (HTO) in young and active patients with focal osteochondral defects of the medial femoral condyle and concomitant varus malalignment. METHODS: Thirty patients with focal osteochondral defects of the medial femoral condyle and varus malalignment >2° were enrolled. All patients were active in sports on a regular base prior to surgery (lifetime), but were unable to perform sports at the time of surgery. Sporting activity 1 year preoperatively and at final follow-up was compared using a previously published sports questionnaire, which assesses sports level, number of sports disciplines, sports frequency, sports duration and the participation in 32 common sports disciplines. Additionally, the Tegner activity scale and the Activity Rating Scale were used. RESULTS: After a mean follow-up of 6.9 years (2.5-9.8; SD 2.4), 76.7 % of patients were participating in sports on a regular basis (Fig. 2). Compared to 1 year preoperatively, there was no difference (n.s.) with regard to sports, the number of sports disciplines, sports frequency and sports duration (Fig. 4). The median Tegner activity scale measured preoperatively 5.0 (2.0-7.0) and post-operatively 5.0 (4.0-7.0) points (Fig. 3), and the ARS changed from 5.7 to 5.3 points (n.s.). The different types of sports disciplines were comparable between 1 year preoperatively and at follow-up. CONCLUSION: A high return to sports rate and an activity level comparable to the state at 1 year preoperatively can be expected in young and active patients after combined OAT and valgus HTO. This seems to be relevant in clinical practice when planning, indicating and performing these complex procedures. LEVEL OF EVIDENCE: IV.

The varus alignment and morphologic alterations of proximal tibia affect the onset of medial knee osteoarthritis in rural Japanese women: Case control study from the longitudinal evaluation of Matsudai Knee Osteoarthritis Survey.

BACKGROUND: Relationship malalignment of the knee and the onset of knee OA are unclear. Moreover, it has not been clarified whether malalignment of the knee affects the morphological change of the proximal tibia. The purpose of current study was to investigate whether varus knee alignment and morphological change of the proximal medial tibia influence the onset of medial knee OA and to clarify the relationship between them. METHODS: The subjects comprised 736 knees from 390 women that went under both the first survey in 1979 and the fourth survey in 2000 in the Matsudai district in Niigata Prefecture in Japan. None of the subjects demonstrated radiographic knee OA at the first survey. OA was graded according to the Kellgren-Lawrence classification and the subjects were divided according to the OA grades in the forth survey into the 3 groups (non-OA, early OA, and advanced OA). Age, BMI, Femorotibial angle (FTA), the tibial plateau angle and medial tibial cortical bone thickness (MTCBT) were measured. We performed multivariate logistic regression analysis using the stepwise method to identified the risk factors regarding onset of knee OA and calculated the odds ratio (OR) and 95% confidence intervals (95% CI). RESULTS: Advanced OA had a significantly higher OR compared to non-OA in 1979 with the tibial plateau angle (OR: 1.15) and MTCBT (OR: 2.11). And also advanced OA had a significantly higher OR compared to early-OA in 1979 with the tibial plateau angle (OR: 1.17) and MTCBT (OR: 1.62). CONCLUSIONS: In the advanced OA, varus alignment of the proximal tibia had already existed before the onset of knee OA. In addition, we thought that varus alignment due to the proximal tibia had influenced the morphologic alterations of proximal medial tibia.

Preoperative varus laxity correlates with overcorrection in medial opening wedge high tibial osteotomy.

PURPOSE: Medial opening wedge high tibial osteotomy (HTO) is a realignment of the lower limb. Despite accurate preoperative planning and careful surgical techniques, many HTOs result in alignment correction errors. These alignment correction errors may be due to soft tissue laxity around the knee such as varus or valgus laxity. The purpose of this study was to examine the relationship of varus and valgus laxity of the knee and alignment correction errors, and to have a formula to predict the subsequent degree of these correction errors. MATERIALS AND METHODS: Fifty knees from 41 patients undergoing opening wedge HTO for knee osteoarthritis were involved. Standing full-length anteroposterior radiographs of the lower limb and the tibia, and varus and valgus stress radiographs of the knee were used to evaluate alignment and joint laxity. Parameters were global correction (the change in the hip-knee-ankle angle), bony correction (the change in the medial proximal tibial angle), and soft tissue correction (global correction - bony correction). RESULTS: The average of global correction, bony correction, and soft tissue correction were 12.8° ± 4.3°, 9.4° ± 3.2°, and 3.4° ± 2.5°, respectively. Preoperative varus laxity was moderately correlated with soft tissue correction (R = 0.58), and in which the slope of the line in the scatter plot represented 0.59, implying that soft tissue correction increases by 0.59° for every 1° of preoperative varus laxity. CONCLUSIONS: Preoperative varus laxity is correlated with soft tissue correction, suggesting that more accurate alignment correction could be achieved by surgical planning taking into account preoperative varus laxity as a factor of soft tissue correction.

High tibial osteotomy for the treatment of medial osteoarthritis of the knee with new iBalance system: 2 years of follow-up.

BACKGROUND: A new system for performing open-wedge high tibial osteotomy (HTO), the iBalance HTO System-Arthrex, has been recently developed in order to make the surgery more reproducible and safe. The aim of this study was to determine the short-term outcomes of the iBalance technique in medial compartment osteoarthritis and varus malalignment of the knee. METHODS: Fifteen patients with a mean age of 50.7 years (SD 5.09), affected by symptomatic varus knee, with medial compartment osteoarthritis (1-2 Ahlbäck degree), were treated with iBalance HTO between July 2011 and February 2012 and evaluated retrospectively. Patients were assessed against the following benchmarks: subjective International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and VAS for pain and Tegner scores, along with X-rays and MRI, before surgery and after a 2-year follow-up. RESULTS: No severe intraoperative complications or implant failures occurred. The mean preoperative scores were as follows: subjective IKDC 66.8 (SD 1.18), KOOS 61.3 (SD 0.86), Vas for pain 8.6 (SD 1.72) and Tegner 4.1 (SD 2.06), while at follow-up the scores were 73.6 (SD 1.01), 88.1 (SD 1.23), 2.9 (SD 2.35) and 3.1 (SD 1.83), respectively. Correction ranged between 3° and 8°. All patients showed complete articular recovery, no loss of correction, no substantial variation in A/P slope and no hardware problems. CONCLUSIONS: iBalance proved to be effective and safe and produced good overall results. Consolidation and osseointegration of the system took place rapidly, while recovery was precocious, comparable with traditional methods and with no severe complications. LEVEL OF EVIDENCE: Case series, Level IV.