Lateral Patellofemoral Osteoarthritis Research Articles

A decreased tibial tuberosity-trochlear groove distance is associated with lateral patellofemoral joint degeneration after implantation of medial fixed-bearing unicompartmental knee arthroplasty - a minimum fiveyear follow-up.

The influence of lateral patellofemoral osteoarthritis (PFOA) in medial unicompartmental knee arthroplasty (UKA) is controversial. Our aim was to identify radiographic factors that may lead to progressive PFOA after implantation of a fixed-bearing medial UKA and their impact on patient-reported outcomes (PROMs). A retrospective consecutive cohort of patients undergoing medial UKA with a minimum follow-up of 60months between September 2011 and January 2017 was identified. All UKAs had a fixed-bearing design with cemented femoral and tibial components. PROMs included documentation of the Oxford Knee Score (OKS). The following radiographic parameters were evaluated on conventional radiographs and computer tomography (CT) scans: patella tilt angle, patella congruence angle, Caton-Deschamps index, medial and lateral patellofemoral degeneration (Kellgren-Lawrence Classification (KL)), mechanical anteroposterior axis, femoral torsion, tibial tuberosity to trochlear groove distance (TTTG), anteroposterior translation of the femoral component. A hierarchical multiple regression analysis and partial Pearson correlation analysis (SPSS) were used to evaluate for predictors of progression of lateral PFOA. Forty-nine knees allowed PFOA assessment and had an average follow-up of 62months (range 60-108). Twenty-three patients did not exhibit any progression of lateral PFOA. Twenty-two progressed with 1 stage, whereas four had progressed 2 stages according to the KL classification. TTTG negatively correlated with progressive lateral PFOA (r = - 0.436, p = 0.01). Progression of lateral PFOA did not correlate with OKS at last follow-up (p = 0.613). A decreased TTGT correlated with radiographic progression of lateral PFOA after medial fixed-bearing cemented UKA. PFOA however did not influence PROMs at a minimum of fiveyears postoperatively.

Association of patellofemoral morphology and alignment with the radiographic severity of patellofemoral osteoarthritis

BackgroundRisk factors for the severity of patellofemoral osteoarthritis (PFOA) are poorly understood. This research aims to evaluate the association between patellofemoral joint (PFJ) morphology and alignment with the radiographic severity of PFOA.MethodsA retrospective analysis of CT scan and lateral radiograph data were acquired in patients with PFOA. The radiographic grade of PFOA and tibiofemoral osteoarthritis (TFOA), lateral and medial trochlear inclination angle, sulcus angle, and the Wiberg classification of patella morphology, the congruence angle, patellar tilt angle, and lateral patellar angles, and tibial tubercle trochlear groove distance (TT-TG) and patella height (i.e., Caton-Deschamps index) were assessed using CT scans and sagittal radiographs of the knee. All the PFJ morphology and alignment data were divided into quarters, and the relationships between each of these measures and the severity of PFOA were investigated.ResultsBy studying 150 patients with PFOA, we found a U-shaped relationship between the Caton-Deschamps index and the severity of PFOA (P < 0.001). A lower value of sulcus angle and lateral patellar angle, a higher value of congruence angle, and type III patella were associated with more severity of lateral PFOA. Compared with the highest quarter of each measure, the adjusted odds ratios (OR) of the severity of PFOA in the lowest quarter of sulcus angle, lateral patellar angle, and congruence angle; and type I patella was 8.80 (p = 0.043), 16.51 (P < 0.001), 0.04 (P < 0.001), and 0.18 (p = 0.048) respectively.ConclusionsExtreme value of patella height, a higher value of lateral patellar displacement and lateral patellar tilt, lower value of sulcus angle, and type III patella were associated with more severity of PFOA.

Arthroscopic Lateral Patellar Facetectomy and Lateral Release Can Be Recommended for Isolated Patellofemoral Osteoarthritis

To analyze the clinical outcomes and survival curve of arthroscopic lateral patellar facetectomy and lateral release for isolated patellofemoral osteoarthritis (PFOA). All patients undergoing arthroscopic lateral patellar facetectomy and lateral release between January 2008 and January 2018 were evaluated retrospectively. The inclusion criteria were 1) diagnosis of isolated symptomatic lateral PFOA, 2) PFOA with kissing lesions (defined as a lesion on both the patella and trochlea, which were in direct contact, 3) arthroscopic lateral patellar facetectomy and lateral release, and 4) two-year minimum follow-up. Evaluation included preoperative and postoperative subjective International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS) scores, and visual analogue pain scale (VAS). The primary end point determining the survival curve was revision of lateral facetectomy. A retrospective analysis was conducted of 61 consecutive arthroscopic lateral patellar facetectomy and lateral release procedures, performed in 55 patients for a diagnosis of isolated PFOA. Five patients were lost to follow-up, leaving 56 knees (50 patients) available at a mean follow up of 7.5 years (range: 2-10). The cohort included 37 women and 13 men with a mean age of 59 years (range: 34-87). Nine patients (18%) underwent revision surgery: six total knee replacements (TKR), two high tibial osteotomies, and one revision arthroscopic lateral patellar facetectomy. The mean time from arthroscopic facetectomy to TKR was 51 months (range: 10-114). The survival curve rate was 86% at 7.5 years. Both KOOS and IKDC scores improved significantly. These results are confirmed by an analysis of MCID. The mean VAS decreased from 6.98 ± 1.2 preoperatively to 2.06 ± 1.6 at the last follow-up (ΔCI95%= [-5.6;-4.4]; P= .0001). Arthroscopic lateral patellar facetectomy and lateral release for isolated PFOA demonstrates sustained significant improvement in knee clinical outcome scores and pain with a low rate of complications and revision surgery at mid-term follow-up. This operation can be recommended in cases of symptomatic isolated PFOA. IV, case series.

Association between Patellofemoral and medial Tibiofemoral compartment osteoarthritis progression: exploring the effect of body weight using longitudinal data from osteoarthritis initiative (OAI).

To investigate the associations of medial and lateral patellofemoral osteoarthritis (PF-OA) at baseline with symptomatic and radiographic OA outcomes in the medial tibiofemoral compartment (MTFC) over 4years, according to baseline overweight status. Data and MRI images of 600 subjects in the FNIH-OA biomarkers consortium were used. Symptomatic worsening and radiographic progression of MTFC-OA were defined using Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain scores and MTFC joint space narrowing (JSN) from baseline to 4-year follow-up. Baseline MRIs were read to establish PF-OA diagnosis. The association between baseline regional PF-OA pattern and odds for MTFC-OA progression was evaluated using regression models (adjusted for relevant confounding covariates including body mass index (BMI), age, sex, PF alignment measurements, KL grade, and knee alignment). To evaluate the effect modifying role for overweight status, stratification analysis was performed (BMI ≥ 25 vs. < 25kg/m2). At baseline, 340 (56.7%), 255 (42.5%), and 199 (33.2%) subjects had OA in the medial, lateral, and both PF compartments. Baseline medial PF-OA was associated with WOMAC pain score and MTFC JSN progression at 4years (Adjusted OR:1.56[95%CI:1.09-2.23] and 1.59[1.11-2.28], respectively) but not lateral PF-OA. In stratification analysis, overweight status was found to be an effect modifier for medial PF-OA and WOMAC pain (OR in overweight vs. non-overweight subjects:1.65[1.13-2.42] vs. 0.50[0.12-1.82]) as well as MTFC-JSN progression (1.63[1.12-2.4] vs. 0.75[0.19-2.81]). In addition to the known confounding effect of BMI for PF-OA and MTFC-OA, the overweight status may also play an effect modifier role in the association between baseline medial PF-OA and MTFC-OA progression, which is amenable to secondary prevention.

Increased femoral antetorsion correlates with higher degrees of lateral retropatellar cartilage degeneration, further accentuated in genu valgum.

The role of increased femoral antetorsion (femAT) as a contributor to patellofemoral (PF) osteoarthritis (OA) is unknown. The purpose of this study was to investigate whether increased femAT was associated with advanced cartilage degeneration in the lateral PF joint. Patients who underwent complete radiographic workup for surgical intervention due to OA in any knee joint compartment were included. Cartilage morphology according to the International Cartilage Repair Society (ICRS) cartilage lesion classification system in the PF joint, femoral and tibial torsion, frontal leg axis, and tibial tuberosity-trochlear groove (TT-TG) distance were assessed. Increased femAT was defined as > 20° according to previous reports. A total of 144 patients were included. Ninety-seven patients had a femAT of < 20° and 45 of > 20°. A significant odds ratio (OR) was found for lateral retropatellar (OR 3.5; p = 0.02) ICRS grade 3 and 4 cartilage degeneration and increased femAT ≥ 20°. In the medial PF compartment, increased femAT had an inverse effect (OR 0.16; p = 0.01). No significant ORs were found for TT-TG distance, tibial torsion, or leg axis. The lateral retropatellar ICRS grade showed a linear correlation to increased femAT values. In valgus knees, isolated lateral PF OA had an even more pronounced correlation to increased femAT (p = 0.004). Increased femAT showed higher grades of lateral retropatellar cartilage degeneration, which was even more pronounced in valgus knees. Cohort study: Level III.

Modified Partial Lateral Facetectomy of the Patella for Stage III Patellofemoral Osteoarthritis with 5-Year Follow-Up.

The main aim of this article was to examine the therapeutic evaluation of our modified partial lateral facetectomy of the patella for stage III lateral patellofemoral osteoarthritis (PFOA), which includes (1) partial lateral patella articular facet that was resected; (2) coronal Z-shaped incision to lengthen lateral retinaculum; (3) patellar perimeter electrocoagulation to denervate. Between December 2008 and January 2013, 36 knees of 32 patients with severe patellofemoral (PF) osteoarthritis (OA) were treated with our modified partial patellar lateral facetectomy. All patients were stage III according to the Iwano scale, and their patellas were all Wiberg type III or Baumgartl type IV in shape. The study group included 6 males and 26 females with an average age of 54.03 years and an average disease course of 8.67 years. The modified Kujala scores were used to evaluate PF function, and the congruence angle was used to evaluate the patellar position. Knee Society Scores (KSS) were used to evaluate overall knee function. Six knees of five cases were lost to follow-up. Thirty knees of 27 cases were followed up for 5 years, with an average follow-up time of 60 ± 3.2 months. The average preoperative modified Kujala score was 15.93, and the average score at last follow-up was 32.03; The satisfactory PF function was achieved in 28 knees (93.33%). The congruence angle improved from preoperative +23. 07 degrees to 11. 91 degrees at the last follow-up. The average preoperative KSS were 110.40 points, which increased to 156.77 points at the last postoperative follow-up. Pain was significantly relieved, and the ability to climb stairs was significantly improved. All scores showed statistically significant improvements after surgery (p < 0.05). No complications were reported. Our modified partial lateral facetectomy of the patella for stage III lateral PFOA can relieve pain and partially improve function. This modified procedure is relatively simple, safe, and an effective treatment method for middle-aged and elderly patients with PFOA. Furthermore, this surgery can be used as an alternative or prephase to total knee arthroplasty. This is a Level IV, therapeutic study.

Partial Patellar Lateral Facetectomy: Arthroscopic Technique

Lateral patellofemoral osteoarthritis is a relatively common condition in young, active patients. Partial lateral patellar facetectomy is a relatively minimally invasive option to restore knee function and return to sport when conservative treatments are insufficient. We describe the arthroscopic technique of partial lateral patellar facetectomy , which has been historically performed as an open procedure. We describe preoperative planning, arthroscopic portals, landmarks, intra-articular evaluation of bone resection, and surgical difficulties. The goal of the preoperative planning was a target bone resection of 10 to 15 mm including osteophytes and the lateral facet of the patella. Arthroscopic anterolateral and anterior superolateral portals were used to achieve the desired resection. An arthroscopic technique allows a direct view of the osteoarthritic bone for removal and permits intraoperative dynamic evaluation, which allows the surgeon to finetune the bone resection and obtain optimal patellar tracking. Avoiding arthrotomy could reduce morbidity and allows a rapid postoperative rehabilitation.

Varus inclination of the tibia is related to patellofemoral osteoarthritis in Japanese female patients with moderate knee osteoarthritis.

The aim of this study was to investigate whether the tibial tuberosity-trochlear groove (TT-TG) distance and lateral patellar tilt, which induce patellofemoral osteoarthritis (OA), are related to the coronal deformity of the lower limb in varus knee OA. It was hypothesized that varus inclination of the tibia was negatively correlated with the TT-TG distance and lateral patellar tilt in Japanese female patients with moderate knee OA. A total of 104 female patients (139 knees) scheduled to undergo knee osteotomy for varus knee OA were enrolled. The coronal lower limb alignment was measured on anteroposterior whole-leg radiographs. The TT-TG distance, patellar tilt angle, and the patellofemoral joint space were measured both medially and laterally on computed tomography images. The correlations between coronal lower limb alignment and the TT-TG distance or patellar tilt angle, and the correlations between the TT-TG distance or patellar tilt angle and patellofemoral joint space were evaluated. The medial proximal tibial angle was negatively correlated with the TT-TG distance (r = - 0.383, P < 0.01) and patellar tilt angle (r = - 0.34, P < 0.01). Lateral patellofemoral joint space was negatively correlated with the TT-TG distance (r = - 0.256, P = 0.002) and patellar tilt angle (r = - 0.205, P = 0.016). Varus inclination of the proximal tibia may induce lateralization of the tibial tuberosity and lateral patellar tilt. The tibial tuberosity lateralization and lateral patellar tilt may induce lateral patellofemoral OA in patients with varus knee OA. III.

Inverted Rearfoot posture in subjects with coexisting patellofemoral osteoarthritis in medial knee osteoarthritis: an exploratory study

BackgroundWhile abnormal rearfoot posture and its relationship to patellofemoral (PF) pain has been thoroughly discussed in the literature, its relationship to patellofemoral osteoarthritis (PFOA) has not been determined. This study aimed to examine whether rearfoot posture is associated with a higher prevalence of radiographic PFOA in a compartment-specific manner in patients with medial tibiofemoral osteoarthritis (TFOA).MethodsParticipants from orthopedic clinics (n = 68, age 56–90 years, 75.0% female), diagnosed with radiographic medial TFOA (Kellgren/Lawrence [K/L] grade ≥ 2) were included in this study. The presence of PFOA and static rearfoot posture were evaluated using a radiographic skyline view and a footprint automatic measurement apparatus, respectively. The relationship between rearfoot posture and PFOA was examined using analysis of covariance and propensity score-adjusted logistic regression analysis.ResultsOn average, patients with coexisting PFOA and medial TFOA (n = 39) had an inverted calcaneus 3.1° greater than those with isolated medial TFOA (n = 29). Increased calcaneus inverted angle was significantly associated with a higher probability of the presence of medial PFOA (odds ratio: 1.180, 95% confidence interval: [1.005, 1.439]; p = 0.043). Calcaneus inverted angle was not associated with higher odds of lateral PFOA presence based on the adjusted values.ConclusionsThe presence of an inverted rearfoot was associated with PFOA. Although these findings do not clearly indicate a biomechanical link between rearfoot posture and PFOA, this study shed light on the potential relationship between altered rearfoot posture and PFOA, as can be seen between rearfoot abnormality and PF pain.

Association of varus thrust with prevalent patellofemoral osteoarthritis: A cross-sectional study

This cross-sectional study investigated (i) the association of varus thrust during gait with the presence of patellofemoral osteoarthritis (PFOA) in patients with medial knee osteoarthritis (OA) and (ii) patellar alignment in the knees with varus thrust. Participants from orthopedic clinics (n=171; mean age, 73.4 years; 71.9% female) diagnosed with radiographic medial knee OA (Kellgren/Lawrence [K/L] grade ≥1) were included in this study, and underwent gait observation for varus thrust assessment using 2D video analysis. A radiographic skyline view was used to assess the presence of medial PFOA using the grading system from the Osteoarthritis Research Society International Atlas. The tibiofemoral joint K/L grade, patellar alignment (i.e., lateral shift and tilting angle), and knee pain intensity were also evaluated as covariates. Thirty-two (18.7%) of 171 patients exhibited varus thrust and they presented significantly higher knee pain (46.0±3.04mm vs. 32.4±2.73mm; P=0.024), a lower patellar tilting angle (P=0.024), and a higher prevalence of PFOA compared with those without varus thrust. A logistic regression analysis with adjustment of covariates showed that varus thrust was significantly associated with higher odds of the presence of mixed and medial PFOA, and trended to significantly associate with any PFOA, including lateral PFOA. This indicates that varus thrust was associated with PFOA in a compartment-nonspecific manner in patients with medial knee OA. Varus thrust may represent a clinical disease feature of more advanced and multicompartmental disease.

Patellofemoral Outcome after Medial Unicompartmental Knee Replacement: A Retrospective Study of 25 Cases

Introduction: Osteoarthritis and impingement, in patellofemoral compartment after partial arthroplasty, have been rarely reported. The purpose of our study was to evaluate outcome at long-term follow-up. Methods: We have reviewed retrospectively twenty-five unicompartmental arthroplasties. The medial parapatellar approach was used in all cases. Patients have been evaluated with regard to patellar impingement and osteoarthritic changes revealed by radiographs. The mean follow-up was 10.4 years. The clinical scoring system of the Knee Society and specific questions regarding patellofemoral symptoms were used for functional outcome. Patellofemoral complications such as osteoarthritis, impingement and the position of the femoral component were diagnosed on X-ray views of the knee. Results: At the final follow-up, fifteen knees revealed lateral patellofemoral osteoarthritis and four knees had patellofemoral impingement. Excepted of two cases, all knees with patella impingement did not revealed degenerative modifications. Anterior pain of the knee was noted more frequently in knees with patellar complications. Patellar impingement was considered the first cause of knee pain, more than knees with degenerative modifications. Only one revision surgery was indicated in front of patellofemoral conflict. The occurrence of patellar impingement depends on the surgical procedure. The anterior position of the femoral component seems to increase the frequency of such complication. Conclusion: Several degenerative modifications may occur in the patello-femoral compartment following partial knee arthroplasty. Patellar impingement and total knee arthritis are the most reported modifications. Functional outcome may be affected progressively when these changes become obvious. Patellar impingement is the major cause of knee pain and needs revision.

Immediate effects of foot orthoses on pain during functional tasks in people with patellofemoral osteoarthritis: A cross-over, proof-of-concept study

BackgroundThe purpose of the study was to determine whether prefabricated foot orthoses immediately reduce pain during functional tasks in people with patellofemoral osteoarthritis, compared to flat insoles and shoes alone. MethodsEighteen people with predominant lateral patellofemoral osteoarthritis (nine women; mean [SD] age 59 [10]years; body mass index 27.9 [3.2]kg/m2) performed functional tasks wearing running sandals, and then wearing foot orthoses and flat insoles (random order). Participants rated knee pain during each task (11-point numerical rating scales), ease of performance and knee stability (five-point Likert scales), and comfort (100mm visual analogue scales). ResultsCompared to shoes alone, foot orthoses (p=0.002; median difference 1.5 [IQR 3]) and flat insoles (p<0.001; 2 [3]) significantly reduced pain during step-downs; foot orthoses reduced pain during walking (p=0.008; 1 [1.25]); and flat insoles reduced pain during stair ambulation (p=0.001; 1 [1.75]). No significant differences between foot orthoses and flat insoles were observed for pain severity, ease of performance or knee stability. Foot orthoses were less comfortable than flat insoles and shoes alone (p<0.05). ConclusionsIn people with patellofemoral osteoarthritis, immediate pain-relieving effects of prefabricated, contoured foot orthoses are equivalent to flat insoles. Further studies should investigate whether similar outcomes occur with longer-term wear or different orthosis designs.

Arthroscopic Lateral Retinacular Release and Modified Elmslie-Trillat Operation Improve Severe Isolated Lateral Patello-Femoral Osteoarthritis.

To evaluate whether arthroscopic lateral retinacular release and the modified Elmslie-Trillat operation improve osteoarthritis (OA) progression and clinical outcomes in patients with severe isolated lateral patello-femoral OA. Nine women (11 knees) and one man (one knee) with isolated late-stage lateral patello-femoral OA underwent surgery. The severity of patello-femoral OA was recorded using the Merchant method, while the level of pain and anterior knee function were scored using the visual analogue scale (VAS) and Kujala knee scores, respectively. The articular cartilage was graded under arthroscopy using the Outerbridge classification. All of the patients underwent the modified Elmslie-Trillat operation after arthroscopic surgery, including lateral retinacular release. Ten patients (12 knees) had a mean 6.45 ± 0.80 mm of medial transfer, 6.02 ± 0.80 mm of anterior transfer of the tibial tubercle, and follow-up of 67.0 months. The mean VAS and Kujala knee scores improved from 8 ± 0.17 preoperatively to 2.33 ± 0.33 on the last follow-up and from 43.08 ± 2.09 to 68.83 ± 2.59, respectively (both p < 0.001). Postoperatively, all had improved subchondral bone remodeling, including cyst resolution, density and trabeculae normalization, and subchondral smoothing in the patello-femoral compartment. The patello-femoral joint space and patellar thickness increased from 0.39 ± 0.16 mm to 1.77 ± 0.18 mm and from 18.28 ± 0.67 mm to 19.60 ± 0.69 mm, respectively (p < 0.001 and p = 0.005). Treatment of severe isolated lateral patello-femoral OA using arthroscopic lateral retinacular release and the modified Elmslie-Trillat operation can improve pain relief, functional outcomes, and subchondral bone remodeling, and also restore the patello-femoral joint space and patellar thickness. Prompt transfer of the tibial tubercle seems to reverse the progress of OA radiographically.

Evaluation of a minimally aggressive method of patellofemoral osteoarthritis treatment at 10 years minimum follow-up

BackgroundKnee osteoarthritis mainly affecting the lateral facet of the patella, especially in young patients, is a definite challenge to the surgeon. Our purpose was to investigate the long-term outcome of a simple operation such as the partial lateral facetectomy on middle-aged to elderly patients with predominant lateral patellofemoral osteoarthritis. MethodsA retrospective, long-term study of 39 knees (28 females, mean aged at surgery 61yearsold) with a minimum follow-up of 10years was performed. Evaluations included preoperative and postoperative questionnaires, physical examinations, and radiographs. ResultsThe main outcomes included the initial anterior pain relief, with higher scores using the Knee Society Score (that improved in 84% of the knees), and the eventual failure of the technique, including percentage of patients that required secondary total knee replacement (30% of the knees). ConclusionPartial lateral facetectomy aiming to decrease the high pressure in the lateral facet of the patella confirmed frequent pain relief. This surgical procedure being minimally invasive, relatively simple, and effective in selected patients, is a valid early alternative to more complex operations and does not preclude further reconstructive surgery in case of disease progression.

The effect of a patellar brace on three-dimensional patellar kinematics in patients with lateral patellofemoral osteoarthritis

Patellar bracing is a mechanical treatment strategy for patellofemoral osteoarthritis (OA) that aims to unload the lateral compartment of the joint by translating the patella medially. Our objective was to determine whether a patellar brace can correct patellar kinematics in patients with patellofemoral OA. We assessed the effect of a patellar brace on three-dimensional patellar kinematics (flexion, spin and tilt; proximal, lateral and anterior translation) at sequential, static knee postures, using a validated magnetic resonance imaging (MRI)-based method, in 19 patients with radiographic lateral patellofemoral OA. Differences in kinematics between unbraced and braced conditions were assessed in the unloaded and loaded knee (15% bodyweight load) using hierarchical linear random-effects models. Random slope and quadratic terms were included in the model when significant (P<0.05). Bracing with load caused the patellae to translate 0.46 mm medially (P<0.001), tilt 1.17° medially (P<0.001), spin 0.62° externally (P=0.012) and translate 1.09 mm distally (P<0.001) and 0.47 mm anteriorly (P<0.001) over the range of knee flexion angles studied. Bracing also caused the patellae to extend in early angles of knee flexion (P<0.001). The brace caused similar trends for the unloaded condition, though magnitudes of the changes varied. Bracing changed patellar kinematics, but these changes did not appear large enough to be clinically meaningful because no reduction in pain was observed in the parent study.

A randomized trial of patellofemoral bracing for treatment of patellofemoral osteoarthritis

The number of effective knee osteoarthritis (OA) interventions, especially those tailored to specific compartmental involvement, are small. The objective of this study was to determine the efficacy of a realigning patellofemoral (PF) brace in improving pain and function among persons with symptomatic lateral PF OA. We conducted a double blind, randomized crossover trial of a realigning PF brace for persons with lateral PF OA. Participants had lateral PF OA with anterior knee symptoms on most days of the month, lateral PF joint space narrowing, and radiographic evidence of a definite osteophyte in the PF joint. We compared two treatments: (1) Control treatment consisting of a BioSkin Q Brace with patellar realigning strap removed; and (2) Active treatment consisting of a realigning BioSkin Q Brace with the strap applied. For each participant, the trial lasted 18 weeks, including 6 weeks each of active and control treatment period separated by a 6-week washout period. The order of treatments was randomized. The primary outcome was change in knee pain on the visual analog scale (VAS). Secondary outcomes included WOMAC pain, function, and stiffness. An unstructured correlation matrix for observations within participants was used in generalized estimating equation fitting to derive a linear regression model that expressed the relation between the intervention and change in VAS pain. 80 participants (63 F) with a mean age and body mass index of 61 years and 28 kg/m(2), respectively, were randomized by order of treatment. A model examining the main effects for change in VAS knee pain (0-100) demonstrated no significant treatment effect (-0.68 VAS units, 95% CI: -6.2, 4.8 units, P=0.81) and no differential carryover effect. There was also no significant difference between active and control treatments for WOMAC pain, function, or stiffness outcomes. The effects of a specific realigning PF brace are not of clinical or statistical significance.

Self‐reported knee and foot alignments in early adult life and risk of osteoarthritis

To determine whether self-reported early adult life malalignment of knees or feet are risk factors for knee or hip osteoarthritis (OA). Participants in the Genetics of Osteoarthritis and Lifestyle case-control database were sent a questionnaire (n = 3,022) containing line-drawing instruments for self-reported knee and foot alignment at ages 20-29 years. Respondents were categorized as having straight, valgus, or varus knee, and straight, toe-in, or toe-out feet. Radiographic criteria were used to define current isolated knee or hip OA, combined knee and hip OA, or non-OA controls. Odds ratios (ORs), adjusted ORs, and 95% confidence intervals (95% CIs) were calculated and logistic regression was performed. The response rate was 72%; 87.5% of responders (n = 1,901) completed the alignment questions. Increased risk of isolated knee OA occurred with early adult varus (adjusted OR 5.16, 95% CI 2.87-9.41) and valgus knees (adjusted OR 3.16, 95% CI 1.04-9.64). The positive association between knee OA and toe-in foot was explained by varus knee. There was an increased risk of combined knee/hip OA from varus (adjusted OR 4.52, 95% CI 2.39-8.53) and valgus knees (adjusted OR 3.07, 95% CI 0.99-9.54). Varus knee was associated with risk of medial tibiofemoral OA, whereas valgus knee was associated with risk of lateral tibiofemoral and lateral patellofemoral OA. Toe-out foot was associated with reduced medial patellofemoral OA. For knee OA, a multiplicative interaction analysis between occupational risks and varus/valgus yielded an OR(int) of 3.20 (95% CI 1.08-9.49). Constitutional alignment of the leg in terms of varus or valgus knee or foot rotation may be a significant factor in determining development and distribution of knee but not hip OA.

The association between patellar alignment on magnetic resonance imaging and radiographic manifestations of knee osteoarthritis

The aim of our study was to evaluate the association between patellar alignment by using magnetic resonance imaging images and radiographic manifestations of patello-femoral osteoarthritis (OA). Subjects were recruited to participate in a natural history study of symptomatic knee OA. We examined the relation of patellar alignment in the sagittal plane (patellar length ratio (PLR)) and the transverse plane (sulcus angle (SA), lateral patellar tilt angle (LPTA), and bisect offset (BO)) to radiographic features of patello-femoral OA, namely joint space narrowing and patellar osteophytes, using a proportional odds logistic regression model while adjusting for age, sex, and bone mass index (BMI). The study sample consisted of 126 males (average age 68.0 years, BMI 31.2) and 87 females (average age 64.7 years, BMI 31.6), 75% of whom had tibiofemoral OA (a Kellgren-Lawrence score of 2 or more). PLR showed a statistically significant association with joint space narrowing and osteophytosis in the lateral compartment. SA showed significant association with medial joint space narrowing and with lateral and medial patellar osteophytosis. LPTA and BO showed significant association with both radiographic indices of the lateral compartment. Clear linear trends were found in association between PLR, LPTA and BO, and with outcomes associated with lateral patello-femoral OA. SA, LPTA, and BO showed linear trends of association with medial joint space narrowing. Results of our study clearly suggest the association between indices of patellar alignment and such features of patello-femoral OA as osteophytosis and joint space narrowing. Additional studies will be required to establish the normal and abnormal ranges of patellar alignment indices and their longitudinal relation to patello-femoral OA.

The Treatment of Patellofemoral Osteoarthritis with Partial Lateral Facetectomy

We investigated the impact of the partial lateral facetectomy of the patella on middle-aged to elderly patients with isolated lateral patellofemoral osteoarthritis. Between 1991 and 2000, we performed partial lateral facetectomy on 11 knees in 11 patients with an average age of 62 years (range, 53-72 years). The mean followup was 8 years (range, 3-14). The average Knee Society Score improved from a preoperative score of 150 to a score of 176 at latest followup. Followup radiographs showed slow progression of osteoarthritis in the patellofemoral and tibiofemoral compartments, but radiographic appearance did not always correlate with clinical symptoms. The success of this procedure depends largely on relief of pain. Partial lateral facetectomy is relatively simple and effective surgical treatment for middle-aged to elderly active patients with isolated lateral patellofemoral osteoarthritis who want to maintain activity level. Therapeutic study, Level IV (case series--no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.

Varus-valgus alignment in the progression of patellofemoral osteoarthritis.

To test the hypotheses that lateral patellofemoral (PF) osteoarthritis (OA) progression is more common than medial PF OA progression, that varus alignment increases the likelihood of medial PF OA progression, and that valgus alignment increases the likelihood of lateral PF OA progression. Patients with knee OA were recruited from the community. Inclusion criteria were definite osteophyte presence (i.e., Kellgren/Lawrence radiographic grade >/=2) in 1 or both knees and at least some difficulty with knee-requiring activity. Varus-valgus alignment (the angle formed by the intersection of the mechanical axes of the femur and tibia) was measured on a full-limb radiograph at baseline. To assess PF OA progression, weight-bearing skyline views of the PF compartment were obtained at baseline and at 18-month followup. Knees with the highest grade of PF narrowing at baseline were excluded from analysis. Logistic regression and generalized estimating equations were used; odds ratios (ORs) were adjusted for age, sex, and body mass index. Lateral PF OA progression, which occurred in 120 (30%) of 397 knees, was more common than was medial PF OA progression, which occurred in 60 knees (15%). Varus (versus nonvarus) alignment increased the odds of PF OA progression isolated to the medial PF compartment (adjusted OR 1.85, 95% confidence interval [95% CI] 1.00-3.44). Valgus alignment increased the odds of PF OA progression isolated to the lateral compartment (adjusted OR 1.64, 95% CI 1.01-2.66). Lateral PF OA progression was more common than medial progression, and varus-valgus alignment influenced the likelihood of PF OA progression in a compartment-specific manner. Interventions that address the stress imposed by alignment on the PF compartments may delay PF OA progression and should be developed.