Static knee alignment is associated with the risk of unicompartmental knee cartilage defects

Although knee malalignment is a risk factor for the progression of unicompartmental knee osteoarthritis (OA), it is unclear how this relationship is mediated. Cartilage defects are known to predate cartilage loss and the onset of knee OA, and it may be that knee malalignment increases the risk of unicompartmental knee cartilage defects. Knee radiographs and MRI were performed on a total of 202 subjects, 36.6% of whom had radiographic knee OA, to determine the relationship between static knee alignment and knee cartilage defects. Analyses were performed for the entire cohort, as well as for healthy and OA subgroups. For every 1° increase in a valgus direction, there was an associated reduced risk of the presence of cartilage defects in the medial compartment of subjects with knee OA (p = 0.02), healthy subjects (p = 0.002), and the combined (p < 0.001) group. Moreover, for every 1° increase in a valgus direction, there was an associated increased risk of the presence of lateral cartilage defects in the OA group (p = 0.006), although the relationship between change toward genu valgum and lateral compartment cartilage defects did not persist for the healthy group (p = 0.16). This cross‐sectional study has demonstrated that knee alignment is associated with the risk for compartment specific knee cartilage defects in both healthy and arthritic people. Given that the natural history of cartilage volume reduction appears to be predated by the presence of cartilage defects, whether knee alignment affects the longitudinal progression from cartilage defects to cartilage loss requires further examination. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:225–230, 2008     

Reliability of radiographic assessment in hip and knee osteoarthritis

OBJECTIVE: To evaluate the reproducibility of commonly used radiographic measures in hip and knee OA and to overcome certain limits of existing knowledge on their reliability from previous studies. DESIGN: Three readers evaluated 100 hip joints (50 pelvic X-rays) and 100 antero-posterior and lateral knee films of a hospital-based sample of patients with radiographic OA at two time points 3 months apart. They retrospectively estimated the presence and severity of joint specific individual radiographic features (osteophyte formation and joint space narrowing at different sites, cysts, subchondral sclerosis, bony deformity and chondrocalcinosis) and two different overall scores. Within and between observer reproducibility was calculated by intra-class correlation coefficient. RESULTS: At the hip joint excellent intra- as well as inter-observer reliability for superior joint space narrowing (JSN) and femoral head deformity could be demonstrated, while the assessment of medial JSN, osteophytes and acetabular sclerosis depends on the level of the investigator's experience. At the knee joint, femorotibial and patellofemoral osteophytes showed a high intra- and inter-observer reliability. Grading of JSN is highly reader dependent; rating of subchondral sclerosis and chondrocalcinosis does not seem to be reproducible enough. The overall scores showed an excellent reproducibility both at hip and knee joints. CONCLUSION: A reliable radiographic severity grading of hip and knee OA is possible with the application of global scores and individual features, if joint specific items are selected and readers are trained enough.     

Effect of frontal plane tibiofemoral angle on the stress and strain at the knee cartilage during the stance phase of gait

Subject‐specific three‐dimensional finite element models of the knee joint were created and used to study the effect of the frontal plane tibiofemoral angle on the stress and strain distribution in the knee cartilage during the stance phase of the gait cycle. Knee models of three subjects with different tibiofemoral angle and body weight were created based on magnetic resonance imaging of the knee. Loading and boundary conditions were determined from motion analysis and force platform data, in conjunction with the muscle‐force reduction method. During the stance phase of walking, all subjects exhibited a valgus–varus–valgus knee moment pattern with the maximum compressive load and varus knee moment occurring at approximately 25% of the stance phase of the gait cycle. Our results demonstrated that the subject with varus alignment had the largest stresses at the medial compartment of the knee compared to the subjects with normal alignment and valgus alignment, suggesting that this subject might be most susceptible to developing medial compartment osteoarthritis (OA). In addition, the magnitude of stress and strain on the lateral cartilage of the subject with valgus alignment were found to be larger compared to subjects with normal alignment and varus alignment, suggesting that this subject might be most susceptible to developing lateral compartment knee OA. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1539–1547, 2010     

Tibial subchondral bone size and knee cartilage defects: relevance to knee osteoarthritis

Unlike knee plain radiography which can only detect joint space narrowing and osteophytes, magnetic resonance imaging can directly visualize and analyse the whole knee structure, including bone size, cartilage defects and loss of cartilage volume. Tibial subchondral bone area expansion may be primary and is associated with risk factors such as age, body mass index (BMI), genetics and/or limb malalignment. It can lead to the development of knee defects, which may also be caused by demographic, anthropometric and environmental factors such as age, female sex, BMI and smoking as well as structural changes such as osteophytes, bone marrow lesions, meniscal tears, meniscal extrusion and ligament abnormalities. Once knee cartilage defects develop, they have a variable natural history but are associated with subsequent cartilage loss in a dose-response manner. Both tibial subchondral bone area and knee cartilage defects are quantitatively related to the severity of knee osteoarthritis (OA), and predictive of the need for knee joint replacement in subjects with knee OA independent of radiographic change. Taken as a whole, these studies suggest that tibial subchondral bone expansion and cartilage defect development represent important targets for the prevention of cartilage loss and joint replacement.     

Meniscal subluxation: association with osteoarthritis and joint space narrowing

OBJECTIVE: Since complete meniscectomy leads to knee OA, we investigated the potential links among meniscal subluxation, joint space narrowing and symptomatic OA. MATERIALS AND METHODS: 233 cases with symptomatic knee OA and 58 asymptomatic controls underwent radiography and MR imaging of the knee. Joint space narrowing was measured on weight-bearing PA fluoroscopy-positioned radiographs. The amount of medial or lateral meniscal subluxation was measured on coronal MR images. The prevalence and severity of meniscal subluxation was compared in cases and controls. We evaluated the correlation of the degree of meniscal subluxation with joint space narrowing, Kellgren and Lawrence grade, and two major risk factors for the development of OA, age and weight. RESULTS: Cases had more medial and lateral subluxation than controls. Mean medial meniscal subluxation was 5.1 mm in cases and 2.8 mm in controls (P=0.001). Modest degrees of meniscal subluxation were common in both cases and controls: 81% of cases and 64% of controls had >/=3 mm of subluxation; age and gender adjusted (P=0.006). Severe degrees of subluxation were almost unique to OA cases (e.g. prevalence of >/=7 mm, 35% cases vs. 7% controls, P< 0.001). Among controls, severe degrees of subluxation were present only in those with radiographic joint space narrowing (defined as >/=grade 1 narrowing on a 0-3 scale). In cases, there was a strong correlation between the degree of medial meniscal subluxation and the severity of medial joint space narrowing (r=0.56, P=0.0001). Similar results were present in the lateral compartment. Meniscal subluxation did not correlate with age or weight. CONCLUSION: Meniscal subluxation is highly associated with symptomatic knee OA. In subjects with osteoarthritis, increasing meniscal subluxation on MR correlates with the severity of joint space narrowing.     

Individuals with high bone mass have an increased prevalence of radiographic knee osteoarthritis

We previously reported an association between high bone mass (HBM) and a bone-forming phenotype of radiographic hip osteoarthritis (OA). As knee and hip OA have distinct risk factors, in this study we aimed to determine (i) whether HBM is also associated with knee OA, and (ii) whether the HBM knee OA phenotype demonstrates a similar pattern of radiographic features to that observed at the hip.HBM cases (defined by DXA BMD Z-scores) from the UK-based HBM study were compared with unaffected family controls and general population controls from the Chingford and Hertfordshire cohort studies. A single blinded observer graded AP weight-bearing knee radiographs for features of OA (Kellgren–Lawrence score, osteophytes, joint space narrowing (JSN), sclerosis) using an atlas. Analyses used logistic regression, adjusting a priori for age and gender, and additionally for BMI as a potential mediator of the HBM–OA association, using Stata v12.609 HBM knees in 311 cases (mean age 60.8 years, 74% female) and 1937 control knees in 991 controls (63.4 years, 81% female) were analysed. The prevalence of radiographic knee OA, defined as Kellgren–Lawrence grade ≥ 2, was increased in cases (31.5% vs. 20.9%), with age and gender adjusted OR [95% CI] 2.38 [1.81, 3.14], p < 0.001. The association between HBM and osteophytosis was stronger than that for JSN, both before and after adjustment for BMI which attenuated the ORs for knee OA and osteophytes in cases vs. controls by approximately 50%.Our findings support a positive association between HBM and knee OA. This association was strongest for osteophytes, suggesting HBM confers a general predisposition to a subtype of OA characterised by increased bone formation.     

Is end-stage lateral osteoarthritic knee always valgus? Mechanical alignment analysis and radiographic severity assessment

Background

We hypothesized that not all persons with end-stage lateral osteoarthritis (OA) have valgus malalignment and that full extension radiographs may underreport radiographic disease severity. The purpose of this study was to examine the demographic and radiographic features of end-stage lateral compartment knee OA.

Materials and methods

We retrospectively studied 133 knees in 113 patients who had undergone total knee arthroplasty between June 2008 and August 2010. All patients had predominantly lateral idiopathic compartment OA according to the compartment-specific Kellgren–Lawrence grade (KLG). The mechanical axis angle (MAA), compartment-specific KLG and joint space narrowing (JSN) of the tibiofemoral joint at extension and 30° of knee flexion, tibia vara angle, tibial slope angle, body mass index, age, and sex were surveyed.

Results

End-stage lateral compartment knee OA has varus (37.6 %), neutral (22.6 %), and valgus (39.8 %) MAA on both-leg standing hip-knee-ankle radiographs. KLGs at 30° of knee flexion (fKLG) were grades 3 and 4 in all patients. However, for KLGs at full extension (eKLG), 54 % of all patients had grades 3 and 4. The others (46 %) showed grades 1 and 2. We observed significant differences in lateral compartment eKLG/eJSN (2.3/2.3 mm in varus, 2.5/1.9 mm in neutral, 2.9/1.6 mm in valgus, p = 0.01 and 0.03, respectively), tibia vara angle (4.9° in varus, 4.1° in neutral, 3.0° in valgus, p < 0.01), and medial compartment eKLG/eJSN (2.1/3.1 mm in varus, 2.0/3.4 mm in neutral, 1.8/4.3 mm in valgus, p < 0.01 and 0.01, respectively) between MAA groups, except for the tibial slope angle (9.7° in varus, 10.1° in neutral, 9.8° in valgus, p = 0.31).

Conclusion

Varus alignment was paradoxically shown in approximately one-third of those with end-stage lateral knee OA on both-leg standing hip-knee-ankle radiographs. Films taken in full extension underreported the degree of OA radiographic severity.

Level of evidence

Level IV, observational study.

     

Frontal plane knee alignment is associated with a longitudinal reduction in patella cartilage volume in people with knee osteoarthritis

OBJECTIVES: Varus-valgus alignment of the knee is increasingly becoming recognised as an important biomechanical variable in patellofemoral osteoarthritis (OA). The aim of this study was to determine the cross-sectional and longitudinal relationships between frontal plane knee alignment and patella cartilage volume in people with knee OA. METHODS: Ninety-nine adults with symptomatic knee OA were recruited using a combined strategy including referral from specialist centres, arthritis support groups and media advertising. Both baseline and follow-up X-rays and magnetic resonance imaging (MRI) were performed 2 years apart. Knee alignment and patella cartilage volume were determined from X-ray and MRI, respectively. RESULTS: Annual change in knee alignment was negatively associated with an annual change in the total patella cartilage volume before (P=0.002) and after (P=0.003) adjustment for potential confounders over an average of a 1.9-year period. For every 1 degrees change towards valgus direction, there was a 23.4-mm(3) [95% confidence interval (CI) 8.1 mm(3)-38.7 mm(3)] annual reduction in the total patella cartilage volume. CONCLUSION: This study is the first to clearly demonstrate and quantitate the annual reduction in patella cartilage volume that occurs as knee alignment becomes increasingly valgus in an osteoarthritic cohort. Interventions that aim to minimise change towards valgus alignment may reduce the risk for the onset and progression of patellofemoral OA.     

Correlation between radiographic severity of knee osteoarthritis and future disease progression. Results from a 3-year prospective,placebo-controlled study evaluating the effect of glucosamine sulfate

OBJECTIVE: To investigate the relationship between baseline radiographic severity of knee osteoarthritis (OA) and the importance of long-term joint space narrowing. DESIGN: Sub-analysis from a three-year randomized, placebo-controlled, prospective study, of 212 patients with knee OA, recruited in an osteoarthritic outpatient clinic and having been part of a study evaluating the effect of glucosamine sulfate on symptom and structure modification in knee OA. MATERIAL AND METHODS: Measurements of mean joint space width (JSW), assessed by a computer-assisted method, were performed at baseline and after 3 years, on weightbearing anteroposterior knee radiographs. RESULTS: In the placebo group, baseline JSW was significantly and negatively correlated with the joint space narrowing observed after 3 years (r=-0.34, P=0.003). In the lowest quartile of baseline mean JSW (<4.5mm), the JSW increased after 3 years by (mean (S.D.)) 3.8% (23.8) in the placebo group and 6.2% (17.5) in the glucosamine sulfate group. The difference between the two groups in these patients with the most severe OA at baseline was not statistically significant (P=0.70). In the highest quartile of baseline mean JSW (>6.2mm), a joint space narrowing of 14.9% (17.9) occurred in the placebo group after 3 years while patients from the glucosamine sulfate group only experienced a narrowing of 6.0% (15.1). Patients with the most severe OA at baseline had a RR of 0.42 (0.17-1.01) to experience a 0.5mm joint space narrowing over 3 years, compared to those with the less affected joint. In patients with mild OA, i.e. in the highest quartile of baseline mean JSW, glucosamine sulfate use was associated with a trend (P=0.10) towards a significant reduction in joint space narrowing. CONCLUSION: These results suggest that patients with the less severe radiographic knee OA will experience, over 3 years, the most dramatic disease progression in terms of joint space narrowing. Such patients may be particularly responsive to structure-modifying drugs.     

Long-term outcome after tibial shaft fracture: is malunion important?

BACKGROUND: Fractures of the shaft of the tibia often heal with some angulation. Although there is biomechanical evidence that such angulation alters load transmission through the joints of the lower limb, it is not clear whether it can eventually lead to osteoarthritis. METHODS: One hundred and sixty-four individuals who had sustained a tibial shaft fracture were assessed in a research clinic thirty to forty-three years after the injury. The subjects were evaluated with regard to self-reported lower limb joint pain, stiffness, and disability (assessed with the Western Ontario and McMaster Universities [WOMAC] osteoarthritis questionnaire); clinical signs of osteoarthritis; and radiographic evidence of osteophytes and joint-space narrowing in the knees, ankles, and subtalar joints. RESULTS: Twenty-two (15%) of the 151 subjects who reported no other knee injury reported at least moderate knee pain, and eight (6%) of the 145 subjects who reported no other ankle injury reported at least moderate ankle pain. Seventeen (13%) of the 135 subjects who reported no other knee or ankle injury reported at least moderate disability. The ipsilateral side demonstrated a higher prevalence than the contralateral side in terms of pain with passive ankle movement (nineteen versus nine subjects, p = 0.02), pain with passive subtalar movement (fifteen versus four subjects, p = 0.01), and radiographic signs of ankle joint space narrowing (twelve subjects versus one subject, p = 0.0055). Knee osteoarthritis was frequently bilateral. Forty-seven fractures (29%) healed with coronal angulation of > or = 5 degrees. Apart from an association between shortening of > or = 10 mm and self-reported knee pain (p = 0.016), there were no significant univariate associations between these malunions and the development of osteoarthritis. Seventeen (15%) of 114 eligible subjects had overall malalignment of the lower limb, defined as a hip-knee-ankle angle outside the normal range of 6.25 degrees of varus to 4.75 degrees of valgus. This malalignment was due to the fracture malunion in nine subjects and predated the fracture in eight. In limbs with varus or valgus malalignment, there was an excess of subtalar stiffness (p = 0.04) and a nonsignificant trend toward more frequent knee pain. In limbs with varus malalignment, there was a nonsignificant trend toward more frequent radiographic evidence of osteoarthritis in the medial compartment of the knee joint. Most of the subjects in whom osteoarthritis was observed had normal overall alignment of the lower limb. CONCLUSIONS: The thirty-year outcome after a tibial shaft fracture is usually good, although mild osteoarthritis is common. Fracture malunion is not the cause of the higher prevalence of symptomatic ankle and subtalar osteoarthritis on the side of the fracture. Although varus malalignment of the lower limb occurs occasionally and may cause osteoarthritis in the medial compartment of the knee, other factors are more important in causing osteoarthritis after a tibial shaft fracture.     

Less valgus alignment in total knee arthroplasty for the varus knee

Constitutional varus of the leg is well recognizable anatomically. Moreland[1] studied long standing radiographs of normal males with a range of varus from 2.6-3° in the proximal tibia. Victor et al. [2] reported constitution varus of 3 degree in 32% men, 17% women. The authors routine technique during total knee arthroplasty (TKA) is to cut the distal femur at 5° valgus and the tibia at neutral for the valgus leg and cut the distal femur at 5° valgus and the tibia 2° varus for varus aligned limbs. 127 consecutive long standing knee radiographs were not retrospectively studied pre and post operatively with 2 year minimum follow up. Average age was 68 years (range 51-90). Average weight was 215 lbs (range 110 – 333). Average tourniquet time was 32 minutes for all patients prior to closure.For the varus group (72 knees), average pre-op tibial femoral alignment was 3.3° varus (range 0-13°). Post-op tibial femoral alignment was 1.2° valgus (range 1° varus - 5° valgus) with the mechanical axis falling into the medial compartment in all patients. Average pre-op knee score was 88 and post-op was 180 at minimum of 2 years.For the valgus group (55 knees), average pre-op tibial femoral alignment was 7.5° (range 2°-24°) valgus. Average post-op tibial femoral alignment was 3.8° (range 1°-10°) valgus. Average pre-op knee score was 107 and post-op was 182 at minimum of 2 years. The authors agree with aiming for valgus alignment for the classic valgus leg (mechanical axis centered on hip, knee, ankle) and less valgus alignment for the varus knee (mechanical axis into the medial compartment). Following the patients anatomy eliminates the need for major soft tissue releases while still avoiding “malalignment”. No special soft tissue releases were required in any patient with pre-op varus or valgus alignment. The clinical outcome is not effected by leaving pre-op varus aligned extremities in less valgus with their TKA’s.     

Knee cartilage defects: association with early radiographic osteoarthritis, decreased cartilage volume, increased joint surface area and type II collagen breakdown

OBJECTIVE: To generate hypotheses regarding the associations between knee cartilage defects and knee radiographic osteoarthritis (ROA), cartilage volume, bone size and type II collagen breakdown in adults. METHODS: A cross-sectional convenience sample of 372 male and female subjects (mean age 45 years, range 26-61) was studied. Knee cartilage defect score (0-4) and prevalence (a defect score of > or =2), cartilage volume, and bone surface area were determined using T1-weighted fat saturation MRI. Urinary levels of C-terminal crosslinking telopeptide of type II collagen (U-CTX-II) were measured by enzyme-linked immunosorbent assay. Height, weight and ROA were measured by standard protocols. RESULTS: In multivariate analysis, the severity and prevalence of knee cartilage defects were significantly and independently associated with tibiofemoral osteophytes (regression coefficient (beta): +0.86 to +1.31/unit, odds ratio (OR): 2.97-3.68/unit, all P<0.05 with the exception of OR in lateral tibiofemoral compartment) and tibial bone area (beta: +0.11 to +0.25/cm2; OR: 1.33-1.58/cm2, all P<0.01). Knee cartilage defects were inconsistently associated with joint space narrowing after adjustment for osteophytes but consistently with knee cartilage volume (beta: -0.27 to -0.70/ml; OR: 0.16-0.56/ml, all P<0.01 except for OR at lateral tibial cartilage site P=0.06). Lastly, knee cartilage defect severity was significantly associated with U-CTX-II (Partial r=+0.18, P<0.001 for total cartilage defect score). CONCLUSION: Osteophytes and increasing knee bone size may be causally related to knee cartilage defects. Furthermore, knee cartilage defects may result in increased cartilage breakdown leading to decreased cartilage volume and joint space narrowing suggesting an important role for knee cartilage defects in early knee OA.     

Effects of the amount of valgus correction for medial compartment knee osteoarthritis on clinical outcome, knee kinetics and muscle co-contraction after opening wedge high tibial osteotomy.

The goal of opening wedge high tibial osteotomy (HTO) is to reduce excessive loading on the medial compartment of the knee by correcting varus deformity, thereby reducing pain and improving function. Although surgical outcome is reportedly poor in cases of under- or overcorrection, the recommended alignment varies. The aim of this study was to investigate the effect of the degree of frontal plane knee alignment following open wedge HTO surgery on muscle co-contraction, joint moments, and self-reported functional outcome. Sixteen patients with medial compartment osteoarthritis (OA), who were scheduled for an opening wedge osteotomy, were recruited for participation in the study. Data were collected using an optoeletric motion analysis system and varus and valgus angulations of the knee were measured, using standing, long cassette, radiographs of the lower extremities. Results showed that physical function improved significantly overall (p < 0.001). However, those subjects whose knee alignment was further away from the group's postoperative mean tended to improve less in their Knee Outcome Survey-Activities of Daily Living Scale (KOS-ADLS) scores than those closer to the mean (p = 0.07). They also had higher medial and lateral co-contractions and higher adduction moments one year after surgery (p 相似文献   

Evaluation of knee and hindfoot alignment before and after total knee arthroplasty: a prospective analysis

A prospective study on 100 cases was performed to evaluate the effect of total knee arthroplasty (TKA) on hindfoot alignment, and to compare knee alignment and hindfoot alignment preoperatively and postoperatively. Preoperative knee alignment ranged from 30 degrees of valgus to 13 degrees of varus. Postoperative knee alignment ranged from 14 degrees of valgus to 0 degrees. Preoperative foot alignment ranged from 22 degrees of valgus to 13 degrees of varus. Postoperative foot alignment ranged from 22 degrees of valgus to 11 degrees of varus. Preoperative knee alignment did not correlate with foot alignment (P =.182). Postoperative knee alignment and foot alignment also showed no correlation (P =.222). Preoperative and postoperative knee alignment were correlated, as expected (P =.000). Notably, hindfoot alignment was changed by knee arthroplasty, and changed in a predictable fashion (P=.000). The alignment of the foot before knee arthroplasty was the largest contributing factor to the hindfoot alignment after arthroplasty of the knee. Hindfoot alignment was changed by TKA, and changed in a predictable fashion.     

High signal in knee osteophytes is not associated with knee pain

OBJECTIVE: Our understanding of the local source of pain in osteoarthritis (OA) remains unclear. We undertook this study to determine if the presence of high-signal osteophytes on magnetic resonance imaging (MRI) was associated with pain presence, location or severity. METHODS: Subjects were chosen from the Boston Osteoarthritis of the Knee Study, a natural history study of symptomatic knee OA. Assessments included knee MRI, pain assessments and information on weight and height. Osteophyte signal was defined as areas of increased signal intensity in the osteophyte on fat-suppressed T2 weighted images, and graded in the joint margins where osteophyte size is graded. All patients were evaluated with the frequent knee symptoms question for pain presence, the Western Ontario McMasters Osteoarthritis Index (WOMAC) for pain severity, and location of self-reported pain was recorded as present or absent based on locations identified on a standardized diagram. The osteophyte signal measures anywhere within one given knee were summed, creating an osteophyte signal aggregate. Logistic regression was conducted with quartile of osteophyte signal aggregate as the independent predictor and frequent knee symptom question as the dependent outcome. Association between quartile of osteophyte signal aggregate and pain severity on WOMAC was assessed using a linear regression. Logistic regression was used to evaluate the association between compartment-specific high-signal osteophytes aggregates (independent variable) and compartment-specific knee pain (dependent variable). Analyses were adjusted for gender, body mass index (BMI), and age. RESULTS: Two hundred and seventeen subjects were included in this analysis. They were predominantly male and 75% of subjects had radiographic tibio-femoral (TF) OA, and the remainder had patello-femoral (PF) radiographic OA. We did not find any association of high-signal osteophytes with presence of pain, pain severity or self-reported pain location. CONCLUSION: High-signal osteophytes detected on MRI are not associated with the presence of pain, pain severity or the self-reported location of pain.     

Windswept deformity in bilateral total knee arthroplasty

Windswept deformity, when an individual has 1 knee in extreme varus alignment and the other in severe valgus alignment, is an unusual occurrence in patients presenting for bilateral total knee arthroplasty. This condition was evaluated in 22 patients to examine possible differences between knees in the same individual. Differences between the varus and valgus knees included alignment (P = .0001), as expected, and the position of the lateral joint line (P = .0161) preoperatively. No significant differences were observed between these 2 knee categories in any other comparison preoperatively or postoperatively. Total knee arthroplasty in patients with windswept deformity can be expected to be successful in both knees when attention is given to proper alignment and soft tissue balancing intraoperatively.     

Association between radiological findings and symptoms at the patellofemoral joint in advanced knee osteoarthritis

We investigated the association between the radiological findings and the symptoms arising from the patellofemoral joint in advanced osteoarthritis (OA) of the knee. Four radiological features, joint space narrowing, osteophyte formation, translation of the patella and focal attrition were assessed in 151 consecutive osteoarthritic knees in 107 patients undergoing total knee replacement. The symptoms which were assessed included anterior knee pain which was scored, the ability to rise from a chair and climb stairs, and quadriceps weakness. Among the radiological features, only patellar translation and obliteration of the joint space had a statistically significant association with anterior knee pain (odds ratio (OR) 4.85; 95% confidence interval (CI) 1.83 to 12.88 and OR 11.23; 95% CI 2.44 to 51.62) respectively. Patellar translation had a statistically significant association with difficulty in rising from a chair (OR 9.06; 95% CI 1.75 to 45.11). Other radiological features, including osteophytes, joint space narrowing, and focal attrition had no significant association. Our study indicates that the radiological findings of patellar translation and significant loss of cartilage are predictive of patellofemoral symptoms and functional limitation in advanced OA of the knee.     

Fixed-flexion knee radiography: the sensitivity to detect knee joint space narrowing in osteoarthritis

OBJECTIVES: Independent reports on the longitudinal performance of non-fluoroscopic fixed-flexion knee radiography have not been published. Therefore, we evaluated the sensitivity of fixed-flexion radiography to detect knee joint space narrowing (JSN) over 2 years in patients with osteoarthritis (OA) and compared the effect of reproducibility and quality of medial tibial plateau (MTP) alignment on sensitivity to JSN. METHODS: Fixed-flexion radiographs of both knees of 193 OA patients were obtained at baseline and after 24 months. Minimum joint space width (JSW) of the medial tibiofemoral joint spaces was measured manually in paired digitised radiographs without knowledge of the chronology. The degree of MTP alignment was assessed by measuring the distance between the anterior and posterior margins of the MTP (intermargin distance [IMD]). Accurate repositioning was achieved if, in the 24-month radiograph, the IMD was reproduced to within 1mm. The quality of MTP alignment was satisfactory if the IMD was 相似文献   

Early radiographic osteoarthritis is associated with substantial changes in cartilage volume and tibial bone surface area in both males and females

OBJECTIVE: To describe the association between early radiographic osteoarthritis of the knee (ROA), knee cartilage volume and tibial bone surface area. METHODS: Cross-sectional convenience sample of 372 male and female subjects (mean age 45 years, range 26-61). Articular cartilage volume, bone area and volume were determined at the patella, medial tibial and lateral tibial compartments by processing images acquired in the sagittal plane using T1-weighted fat saturation MRI. ROA was assessed with a standing semiflexed radiograph and the OARSI atlas for joint space narrowing and osteophytosis. Both radiographs and MRIs were performed in the right knee and read by different observers. RESULTS: ROA (predominantly grade 1) was present in 17% of subjects of which medial joint space narrowing was most common (14%) followed by medial osteophytes (6%). Grade one medial joint space narrowing was associated with substantial reductions in cartilage volume at both the medial and lateral tibial and patellar sites within the knee (adjusted mean difference 11-13%, all P<0.001) while grade one osteophytosis was associated with substantial increases in both lateral and medial tibial joint surface area (adjusted mean difference 10-16%, all P<0.001). In contrast, osteophytosis was not associated with a significant change in cartilage volume and joint space narrowing was not associated with a significant change in tibial bone area (all P>0.05). CONCLUSIONS: Early medial compartment ROA is associated with substantial reductions in cartilage volume and increases in bone area. These large changes, when combined with similar measurement error for MRI and radiographs, suggest that MRI may be superior at detecting and hence understanding early osteoarthritis of the knee in humans.