Patellofemoral Joint Osteoarthritis Research Articles

Associated patellofemoral osteoarthritis is not a contraindication for unicompartmental knee replacement. Report of one hundred ten prostheses with an average 6-year follow-up

IntroductionAssociated patellofemoral joint osteoarthritis (APFJ-OA) has typically been considered a contraindication for unicompartmental knee arthroplasty (UKA) in the treatment of femorotibial joint osteoarthritis. However, this contraindication is being challenged. The aim of this study was to assess clinical and functional outcomes, complications, and implant survival in medial or lateral UKA, regardless of clinical symptoms or radiographic signs of APFJ-OA. MethodsThis retrospective, comparative study included patients treated with medial or lateral UKA regardless of preoperative symptoms or signs of APFJ-OA, with a minimum 2-year follow-up. Intraoperatively, knees were subdivided based on APFJ-OA grade, according to the Outerbridge classification. Clinical and functional outcomes were analyzed using the 2011 Knee Society Score (KSS) at the last follow-up control. APFJ-OA was treated systematically, in a tailored, stepwise fashion according to its severity. Complications and implant survival rates were evaluated. Two-sided paired T-test, ANOVA, and Kruskal–Wallis tests were used with a significance level of 5%. ResultsFinally, 110 UKAs were assessed 81 (73.6%) medial and 29 (26.4%) laterals. The average follow-up was 6 years (2–19.5). According to Outerbridge, 22 knees (20%) were in grade 2, 59 (53.6%) were in grade 3, and 29 (26.4%) were in grade 4. All three groups showed a statistically significant increase in KSS scores and range of motion. There were no significant differences in clinical KSS improvement and flexion contracture between Outerbridge groups (average 35.7 and −4.9, respectively). Group 3 showed statistically significant improvement in functional KSS when compared to group 2 (68.8 vs 61.2). In maximum flexion, groups 3 and 4 did significantly better than group 2 (20° vs 15°). Three prostheses (2.7%) needed revision after 7, 8.6, and 12 years due to aseptic tibial loosening. Implant survival was 100% at 5 (64 of 64), 97% at 7 (30 of 31), 93% at 9 (14 of 15), and 89% at 12 years, respectively (8 of 9). ConclusionClinical and functional results, complications, and survival of medial or lateral UKA were not negatively affected by APFJ-OA assessed intraoperatively using the Outerbridge classification after an average follow-up of 6 years. We consider that APFJ-OA is not a contraindication for UKA when treated systematically according to its severity. Level of evidenceIV.

Should we recommend patellofemoral arthroplasties to patients?

AimsWith up to 40% of patients having patellofemoral joint osteoarthritis (PFJ OA), the two arthroplasty options are to replace solely the patellofemoral joint via patellofemoral arthroplasty (PFA), or the entire knee via total knee arthroplasty (TKA). The aim of this study was to assess postoperative success of second-generation PFAs compared to TKAs for patients treated for PFJ OA using patient-reported outcome measures (PROMs) and domains deemed important by patients following a patient and public involvement meeting.MethodsMEDLINE, EMBASE via OVID, CINAHL, and EBSCO were searched from inception to January 2022. Any study addressing surgical treatment of primary patellofemoral joint OA using second generation PFA and TKA in patients aged above 18 years with follow-up data of 30 days were included. Studies relating to OA secondary to trauma were excluded. ROB-2 and ROBINS-I bias tools were used.ResultsA total of nine studies were included, made up of four randomized controlled trials (domain 1) and five cohort studies (domain 2). PROMs and knee function specific scores developed for reporting TKA were unable to detect any difference between PFA and TKA. There was no significant difference in complications between PFA and TKA. PFAs were found to have a better postoperative range of motion.ConclusionTKA and PFA are both viable options for patients with primary PFJ OA. Over time, we have seen an emphasis on patient satisfaction and better quality of life. Recommending sacrificing healthy medial and lateral compartments to treat patellofemoral joint arthritis should be given further thought.Cite this article: Bone Jt Open 2023;4(12):948–956.

Quadriceps tendon malalignment is an independent anatomical deformity which is the primary abnormality associated with lateral facet patellofemoral joint osteoarthritis.

The purposes of this study are to, firstly, develop techniques to accurately identify extensor mechanism malalignment by measuring the alignment of the quadriceps tendon (QTA) with computerized tomography (CT) scans. Secondly, to investigate correlations between QTA and lower limb bony anatomical variations within a representative normal population. Lastly, to evaluate the clinical significance of QTA by establishing its potential connection with lateral facet patellofemoral joint osteoarthritis (LFPFJOA). CT scans were orientated to a mechanical axis reference frame and three techniques developed to measure the alignment of the quadriceps tendon. Multiple measurement of bony alignment from the hip to the ankle were performed on each scan. A series of 110 cadaveric CT scans were measured to determine normal values, reproducibility, and correlations with bony anatomy. Secondly, a comparison between 2 groups of 25 patients, 1 group with LFPFJOA and 1 group with isolated medial OA and no LFPFJOA. From the cadaveric study, it was determined that the alignment of the quadriceps tendon is on average 4.3° (SD 3.9) varus and the apex of the tendon is 9.1mm (SD 7.7mm) lateral to the trochlear groove and externally rotated 1.9° (SD 12.4°) from the centre of the femoral shaft. There was no association between the quadriceps tendon alignment and any other bony measurements including tibial tubercle trochlear groove distance (TTTG), coronal alignment, trochlear groove alignment and femoral neck anteversion. A lateralized QTA was significantly associated with LFPFJOA. QTA in the LFPFJOA group was 9.6° varus (SD 2.8°), 21.3mm (SD 6.6) lateralised and 17.3° ER (SD 11°) compared to 5.5° (SD 2.3°), 10.7mm (SD 4.9) and 3.3° (SD 7.2°), respectively, in the control group (p < 0.001). A significant association with LFPFJOA was also found for TTTG (17.2mm (SD 5.7) vs 12.1mm (SD 4.3), p < 0.01). Logistic regression analysis confirmed the QTA as having the stronger association with LFPFJOA than TTTG (AUC 0.87 to 0.92 for QTA vs 0.79 for TTTG). These studies have confirmed the ability to accurately determine QTA on CT scans. The normal values indicate that the QTA is highly variable and unrelated to bony anatomy. The comparative study has determined that QTA is clinically relevant and a lateralised QTA is the dominant predictor of severe LFPFJOA. This deformity should be considered when assessing patella maltracking associated with patella osteoarthritis, patella instability and arthroplasty. III (retrospective cohort study).

The effects of a sleeve knee brace during stair negotiation in patients with symptomatic patellofemoral osteoarthritis

BackgroundThe patellofemoral joint is an important source of pain in knee osteoarthritis. Most biomechanical research in knee osteoarthritis has focused on the tibiofemoral joint during level walking. It is unknown what happens during stair negotiation in patients with patellofemoral joint osteoarthritis, a task commonly increasing pain. Conservative therapy for patellofemoral joint osteoarthritis includes the use of a sleeve knee brace. We aimed to examine the effect of a sleeve knee brace on knee biomechanics during stair negotiation in patellofemoral joint osteoarthritis patients. Methods30 patellofemoral joint osteoarthritis patients (40–70 years) ascended and descended an instrumented staircase with force plates under two conditions – wearing a Lycra flexible knee support (Bioskin Patellar Tracking Q Brace) and no brace (control condition). Knee joint kinematics (VICON) and kinetics were recorded. FindingsDuring stair ascent, at the knee, the brace significantly reduced the maximal flexion angle (2.70, P = 0.002), maximal adduction angle (2.00, P = 0.044), total sagittal range of motion (2.00, P = 0.008), total frontal range of motion (1.70, P = 0.023) and sagittal peak extension moment (0.05 Nm/kg, P = 0.043) compared to control. During stair descent, at the knee, the brace significantly reduced the maximal flexion angle (1.80, P = 0.039) and total sagittal range of motion (1.50, P = 0.045) compared to control. InterpretationThe small changes in knee joint biomechanics during stair negotiation observed in our study need to be investigated further to help explain mechanisms behind the potential benefits of a sleeve knee brace for painful patellofemoral joint osteoarthritis.

SURVIVORSHIP AND FUNCTIONAL OUTCOMES OF FEMORO PATELLA VIALLI PATELLOFEMORAL JOINT REPLACEMENTS

AbstractIntroductionIsolated patellofemoral joint(PFJ) osteoarthritis affects approximately 10% of patients aged over 40 years and treatment remains controversial. Our aim was to evaluate long term functional and radiological outcomes following PFJ arthorplasty with the Femoro Patella Vialli (FPV) prosthesis as this evidence is lacking in literature.MethodologyA retrospective review of prospectively collected PROMS in patients undergoing Patellofemoral arthroplasty. Single centre trial. Between 2004 and 2008, 101 FPV patellofemoral arthroplasties were performed in 80 patients with isolated patellofemoral joint osteoarthritis. Data was collected as a part of routine follow-up for up to 6 years and additional long term data was collected at 16 years.ResultsAt 6 year follow up the mean OKS was 29 and by 16 year follow up it was 26 which was not a statistically significant drop. 22 patients (29 knees) had died, 32 (32%) had been revised, 25 to total knee replacement using primary arthroplasty components. Mean OKS in the revised group was 27 which was not a statistically significant difference when compared to the unrevised group. Mean time to revision was 4 years. The cumulative survival analysis of the FPV implant was 76% at 5 years, 64% at 10 years.ConclusionOur findings suggest the FPV patellofemoral prosthesis provides good pain relief and clinical outcomes however, the survivorship for this particular implant maybe lower as compared to the available literature. Patient reported outcomes are maintained over the implant life and are no worse once revised implying a staged approach to arthroplasty is reasonable.

Assessments of early patellofemoral joint osteoarthritis features after anterior cruciate ligament reconstruction: a cross-sectional study

BackgroundPersistent anterior knee pain and subsequent patellofemoral joint (PFJ) osteoarthritis (OA) are common symptoms after anterior cruciate ligament reconstruction (ACLR). Quadriceps weakness and atrophy is also common after ACLR. This can be contributed by arthrogenic muscle inhibition and disuse, caused by joint swelling, pain, and inflammation after surgery. With quadriceps atrophy and weakness are associated with PFJ pain, this can cause further disuse exacerbating muscle atrophy. Herein, this study aims to identify early changes in musculoskeletal, functional and quality of health parameters for knee OA after 5 years of ACLR.MethodsPatients treated with arthroscopically assisted single-bundle ACLR using hamstrings graft for more than 5 years were identified and recruited from our clinic registry. Those with persistent anterior knee pain were invited back for our follow-up study. For all participants, basic clinical demography and standard knee X-ray were taken. Likewise, clinical history, symptomatology, and physical examination were performed to confirm isolated PFJ pain. Outcome measures including leg quadriceps quality using ultrasound, functional performance using pressure mat and pain using self-reported questionnaires (KOOS, Kujala and IKDC) were assessed. Interobserver reproducibility was assessed by two reviewers.ResultsA total of 19 patients with unilateral injury who had undergone ACLR 5-years ago with persistent anterior knee pain participated in this present study. Toward the muscle quality, thinner vastus medialis and more stiffness in vastus lateralis were found in post-ACLR knees (p < 0.05). Functionally, patients with more anterior knee pain tended to shift more of their body weight towards the non-injured limb with increasing knee flexion. In accordance, rectus femoris muscle stiffness in the ACLR knee was significantly correlated with pain (p < 0.05).ConclusionIn this study, it was found that patients having higher degree of anterior knee pain were associated with higher vastus medialis muscle stiffness and thinner vastus lateralis muscle thickness. Similarly, patients with more anterior knee pain tended to shift more of their body weight towards the non-injured limb leading to an abnormal PFJ loading. Taken together, this current study helped to indicate that persistent quadriceps muscle weakness is potential contributing factor to the early development of PFJ pain.

Patellofemoral joint geometry and osteoarthritis features 3-10 years after knee injury compared with uninjured knees.

In this cross-sectional study, we compared patellofemoral geometry in individuals with a youth-sport-related intra-articular knee injury to uninjured individuals, and the association between patellofemoral geometry and magnetic resonance imaging (MRI)-defined osteoarthritis (OA) features. In the Youth Prevention of Early OA (PrE-OA) cohort, we assessed 10 patellofemoral geometry measures in individuals 3-10 years following injury compared with uninjured individuals of similar age, sex, and sport, using mixed effects linear regression. We also dichotomized geometry to identify extreme (>1.96 standard deviations) features and assessed likelihood of having extreme values using Poisson regression. Finally, we evaluated the associations between patellofemoral geometry with MRI-defined OA features using restricted cubic spline regression. Mean patellofemoral geometry did not differ substantially between groups. However, compared with uninjured individuals, injured individuals were more likely to have extremely large sulcus angle (prevalence ratio [PR] 3.9 [95% confidence interval, CI: 2.3, 6.6]), and shallow lateral trochlear inclination (PR 4.3 (1.1, 17.9)) and trochlear depth (PR 5.3 (1.6, 17.4)). In both groups, high bisect offset (PR 1.7 [1.3, 2.1]) and sulcus angle (PR 4.0 [2.3, 7.0]) were associated with cartilage lesion, and most geometry measures were associated with at least one structural feature, especially cartilage lesions and osteophytes. We observed no interaction between geometry and injury. Certain patellofemoral geometry features are correlated with higher prevalence of structural lesions compared with injury alone, 3-10 years following knee injury. Hypotheses generated in this study, once further evaluated, could contribute to identifying higher-risk individuals who may benefit from targeted treatment aimed at preventing posttraumatic OA.

Lower Patellofemoral Joint Contact Force During Side-Step Cutting After Return-to-Sports Clearance Following Anterior Cruciate Ligament Reconstruction

Background: Low patellofemoral joint (PFJ) contact force has been associated with PFJ osteoarthritis. Quadriceps force and knee flexion angles, which are typically altered after an anterior cruciate ligament reconstruction (ACLR), primarily influence PFJ contact forces. It is still inconclusive whether differences in PFJ contact forces are present during high knee flexion tasks such as side-step cutting after clearance to return to sports (RTS) after ACLR. Purpose: To explore PFJ contact forces in the ACLR limb and compare them with those of the contralateral and control limbs during side-step cutting tasks after clearance to RTS. Study Design: Controlled laboratory study. Methods: A total of 26 male athletes with ACLR who were previously cleared to RTS were matched with 23 healthy men serving as the control group. Three-dimensional motion capture and force plate data were collected while both groups performed anticipated side-step cutting tasks. Joint kinematics, kinetics, muscle forces, and PFJ contact forces were calculated using musculoskeletal modeling. Results: Peak PFJ force was lower in the ACLR limbs compared with the contralateral limbs (mean difference [MD], 5.89 body weight [BW]; 95% CI, 4.7-7.1 BW; P < .001) and the control limbs (MD, 4.44 BW; 95% CI, 2.1-6.8 BW; P < .001). During peak PFJ force, knee flexion angle was lower in ACLR limbs compared with the contralateral (MD, 4.88°; 95% CI, 3.0°-6.7°; P < .001) and control (MD, 6.01°; 95% CI, 2.0°-10.0°; P < .002) limbs. A lower quadriceps force compared with the contralateral (MD, 4.14 BW; 95% CI, 3.4-4.9 BW; P < .001) and control (MD, 2.83 BW; 95% CI, 1.4-4.3 BW; P < .001) limbs was also found. Conclusion: Lower PFJ contact forces and a combination of quadriceps force deficits and smaller knee flexion angle were found in the ACLR compared with the contralateral and control limbs even after clearance to RTS. Clinical Relevance: Despite rehabilitation and subsequent clearance to RTS, differences in PFJ contact forces are present after ACLR. Current rehabilitation and RTS battery may not be effective and sensitive enough to identify and address these differences.

Patellofemoral Arthroplasty Is an Efficient Strategy for Isolated Patellofemoral Osteoarthritis with or without Robotic-Assisted System.

There is relative paucity in the literature concerning outcomes after robotic-assisted Patellofemoral Arthroplasty (PFA). The aims were (1) to evaluate outcomes in patients undergoing PFA with inlay or onlay components, with or without robotic arm assistance and (2) to identify risk factors of poor outcomes after PFA. This retrospective study included 77 PFA for isolated patellofemoral joint osteoarthritis, assigned to three groups (18 conventional technique, 17 image-free robotic-assisted system and 42 image-based robotic-assisted system). The demographic data were comparable between the three groups. The clinical outcomes assessed were: Visual Analogue Scale, Knee Society Score, Kujala score and satisfaction rate. The radiological measures were: Caton Deschamps index, patellar tilt and frontal alignment of the trochlea. Functional outcomes, satisfaction rate and residual pain were comparable between the three groups. Patellar tilt improvement was superior when a robotic device was used (either image-based or image-free) compared to the conventional technique. There were three revisions (3.9%) at the last follow-up related to femorotibial osteoarthritis progression. Multivariate analysis found no significant risk factors for poor outcomes, with respect to the surgical technique or implant design. Functional outcomes and revisions rate after PFA were comparable between the surgical techniques and implants. Robotic-assisted systems were associated with a superior improvement of the patellar tilt compared to the conventional technique.

Patellofemoral joint loading and early osteoarthritis after ACL reconstruction.

Patellofemoral joint (PFJ) osteoarthritis is common following anterior cruciate ligament reconstruction (ACLR) and may be linked with altered joint loading. However, little is known about the cross-sectional and longitudinal relationship between PFJ loading and osteoarthritis post-ACLR. This study tested if altered PFJ loading is associated with prevalent and worsening early PFJ osteoarthritis post-ACLR. Forty-six participants (mean ± 1 SD age 26 ± 5 years) approximately 1-year post-ACLR underwent magnetic resonance imaging (MRI) and biomechanical assessment of their reconstructed knee. Trunk and lower-limb kinematics plus ground reaction forces were recorded during the landing phase of a standardized forward hop. These data were input into a musculoskeletal model to calculate the PFJ contact force. Follow-up MRI was completed on 32 participants at 5-years post-ACLR. Generalized linear models (Poisson regression) assessed the relationship between PFJ loading and prevalent early PFJ osteoarthritis (i.e., presence of a PFJ cartilage lesion at 1-year post-ACLR) and worsening PFJ osteoarthritis (i.e., incident/progressive PFJ cartilage lesion between 1- and5-years post-ACLR). A lower peak PFJ contact force was associated with prevalent early PFJ osteoarthritis at 1-year post-ACLR (n = 14 [30.4%]; prevalence ratio: 1.37; 95% confidence interval [CI]: 1.02-1.85) and a higher risk of worsening PFJ osteoarthritis between 1- and 5-years post-ACLR (n = 9 [28.1%]; risk ratio: 1.55, 95% CI: 1.13-2.11). Young adults post-ACLR who exhibited lower PFJ loading during hopping were more likely to have early PFJ osteoarthritis at 1-year and worsening PFJ osteoarthritis between 1- and 5-years. Clinical interventions aimed at mitigating osteoarthritis progression may be beneficial for those with signs of lower PFJ loading post-ACLR.

Patellofemoral osteoarthritis does not influence clinical outcomes of fixed-bearing unicompartmental knee arthroplasty.

Unicompartmental knee arthroplasty (UKA) is an ideal surgical approach in treatment of end-stage knee osteoarthritis (KOA), however, indications of UKA have been controversial, and the radiographic and symptomatic patellofemoral osteoarthritis (PFOA) are often considered as a contraindication of medial UKA. 337 fixed bearing UKAs were retrospectively recruited in our joint center between January 1, 2011 and June 30, 2020. There were 105 patients accompanied by PFOA and 232 patients have normal PF joint. International Cartilage Repair Society (ICRS) system was introduced to quantify the degeneration degree of PF joint. Oxford Knee Score (OKS), Forgotten Joint Score (FJS), Kellgren-Lawrence (K-L) classifying system and visual analogue scale (VAS) were adopted to evaluate outcomes between with and without PFOA. There was no significant difference of age, BMI, gender, OKS, FJS and other variables between PFOA and Non-PFOA group. After more than 5 years follow-up, UKA patients with or without PFOA could all achieve a satisfactory improvement of OKS, VAS and FJS score. ROM of the replaced knee increased from preoperative 110° to 130°. 74.3% (78/105) and 75.0% (174/232) patients have no change of K-L grade in PFOA and Non-PFOA group, OKS, FJS, VAS score and ROM were also comparable in all patients and no significant outcomes difference were found between two group. The presence of patellofemoral joint osteoarthritis and anterior knee pain should not be considered to be contraindications to medial fixed-bearing UKA.

Effect of medial open wedge high tibial osteotomy on progression of patellofemoral osteoarthritis

PurposeThis study aimed to investigate the effect of medial open wedge high tibial osteotomy (MOWHTO) on patellofemoral joint osteoarthritis (PF OA) progression and its outcome according to the degree of preexisting PF OA.Materials and methodsPatients who underwent biplane MOWHTO between January 2006 and December 2018 were retrospectively reviewed. The patients were divided into two groups according to the degree of PF OA: non-PF OA [Kellgren–Lawrence (K–L) grade 0–1] and PF OA (K–L grade 2–3). Propensity score matching was performed between the two groups, and comparative analysis was performed on clinical scores and radiographic parameters and grade.ResultsAfter propensity score matching, 83 patients were selected for each group. At postoperative follow-up, clinical scores were improved significantly compared with preoperative scores in both groups; however, there were no significant differences between the groups. There were also no significant differences between the two groups in radiographic parameters. The radiographic grade of PF OA indicated a slight progression in osteoarthritis in both groups; however, PF OA tended to progress further in the PF OA group.ConclusionsMOWHTO did not result in significant differences in outcomes at postoperative follow-up; however, preexisting PF OA contributed to PF OA progression after MOWHTO.

Poster 242: Deep Learning for Identifying Patellofemoral Measurements Associated with Cartilage Lesions on MRI

Poster 242: Deep Learning for Identifying Patellofemoral Measurements Associated with Cartilage Lesions on MRI

Knee Injury and Osteoarthritis Outcome Score Patellofemoral Questionnaire: Psychometric Properties among Females of Kingdom of Saudi Arabia

Patellofemoral joint osteoarthritis (PFJ-OA), being a subset of knee osteoarthritis (KOA), is evident in adults, and its prevalence is greater in women in Saudi Arabia too. To assess its disease dimensions, the ‘Knee Injury and Osteoarthritis Outcome Score Patellofemoral’ questionnaire (KOOS-PF) is frequently used to measure symptoms and function among the people with PFJ-OA. Cross-cultural validation is ongoing in several languages, and it needed to be validated among females in Arabic. Therefore, aiming to translate, cross-culturally adapt and validate its psychometric properties, a cross-sectional study was designed where the Ar-KOOS-PF-F was administered among 105 females. The demographic characteristics of recruited females were 51.62 (8.49) years and 30.12 (3.70) kg/m2. Cronbach’s alpha was used for internal consistency (IC) and the questionnaire was re-administered after 48 h to estimate the test–retest reliability (92 females, 87.61% compliance rate). Concurrent validity was also established with a visual analog scale (VAS). Factorial validity was established by principal component analysis (PCA). The psychometric properties were: excellent internal consistency of Cronbach’s alpha (α) = 0.930, intraclass correlation coefficient (ICC) for intra-ratter reliability = 0.960 (0.915–0.999), test–retest reliability, ICC = 0.893 (0.889–0.970), standard error of measurement (SEM) = 2.46, relative standard deviation/coefficient of variance (RSD/CV) = 29.9%, minimal detectable change (MDC%) = 22.96% and good concurrent validity with VAS (r = −0.783; p = 0.023). The best-fit four-factor model for confirming overall item communalities ranged from 0.529 to 0.867, which indicates moderate to high communalities, and confirms the homogeneity of Ar-KOOS-PF-F using PCA. The floor (0.9%) and ceiling effects (13.6%) were also within the limits. This scale can be used among females, as it has acceptable psychometric properties of scale validation.

LOWER-LIMB BIOMECHANICS DURING WALKING IN PEOPLE WITH PATELLOFEMORAL JOINT OSTEOARTHRITIS, ASSOCIATIONS WITH SEX AND SYMPTOMS SEVERITY.

Purpose: - To determine if women with Patellofemoral joint (PFJ) Osteoarthritis (OA) have different walking biomechanics than men with PFJ OA - To determine if women with PFJ OA have different walking biomechanics to women without - To explore the relationship between a person's burden of PFJ OA and joint moment impulse, and if these relationships are sex-dependent

ASSOCIATIONS BETWEEN QUADRICEPS PASSIVE STIFFNESS AND PATELLOFEMORAL JOINT ALIGNMENTS IN SENIOR ADULTS

Purpose: Patellar malalignments would increase patellofemoral joint (PFJ) stress causing pain and structural changes, which are associated with PFJ osteoarthritis. The individual muscle heads of quadriceps have force vectors pulling the patella to the different directions of translation and rotation. The active contraction of the quadriceps muscle has been known to be crucial for normal patellar tracking. In addition to active tension, increased muscle passive stiffness, characterized by altered elasticity, may also affect patellar positions.

Parathyroid Hormone (1-34) Attenuates Cartilage Degradation and Preserves Subchondral Bone Micro-architecture in Rats with Patella Baja-Induced-Patellofemoral Joint Osteoarthritis.

Several studies have revealed that PTH1-34 may possess the potential for treating osteoarthritis (OA) and osteoporosis. However, no study has yet determined whether PTH1-34 can be used for the treatment of patella baja-induced patellofemoral joint OA (PFJOA). Thus, this study sought to assess the efficacy of PTH1-34 for the treatment of PFJOA in a rat model. Patella baja was induced in 3-month-old female Sprague-Dawley (SD) rats by patellar ligament shortening (PLS), after which the rats were randomly divided into three groups (n = 12): Sham, PLS, and PTH group (PTH + PLS, PTH1-34, 30µg/kg/d, 5days per week for 10weeks). Thereafter, radiographic imaging, macroscopic and microscopic analyses, immunohistochemistry, and microcomputed tomography (CT) analysis were performed. The appearance of PLS-induced PFJOA promoted obvious changes in the patellar position and structure in the PLS group, which were characterized by cartilage degeneration, subchondral bone microstructure deterioration, patella baja, and increasing patella length. However, these negative characteristics were markedly ameliorated by PTH1-34, which not only inhibited cartilage catabolism by decreasing MMP-13 and ADAMTS-4 but also enhanced anabolism by increasing Col-II and Aggrecan. Furthermore, the micro-CT results showed a marked improvement in subchondral bone microarchitecture. The findings presented herein demonstrated that early treatment with PTH1-34 could improve cartilage metabolism and subchondral bone health in this PFJOA model.

Patellar button compatibility in the conversion of Patellofemoral Arthroplasty to a Total Knee Arthroplasty: A review of the contemporary literature.

Compared to total knee arthroplasty (TKA), patellofemoral arthroplasty (PFA) is a far less commonly performed operation. However, in carefully selected cohorts, PFA continues to be an appropriate treatment option for end-stage isolated patellofemoral joint osteoarthritis. In the later situation whereby a PFA is considered for conversion to a TKA - often due to disease progression - uncertainty remains regarding optimal management of the in situ patellar button. This review of the contemporary literature aimed to provide a summary of the current evidence to support surgeon decision-making, by evaluating the compatibility, efficacy, and survivorship of retained versus revised patellar buttons in PFA-to-TKA conversion. Specific focus was paid to implant design and technical considerations during revision, plus post-operative patient-reported outcomes and modes of secondary patellar component failure. A review of the Embase, Cochrane and PubMed databases was performed following PRISMA search principles. This investigation highlights that the fate of patellar buttons in PFA-to-TKA conversion has previously been poorly studied, with scant publication data available. Most reports have been of singular cases or small cohort series. Larger formal RCTs and level 1 evidence are lacking. The findings herein suggest that surgeons can confidently retain well-fixed, undamaged, dome-shaped all-polyethylene patellar buttons in the conversion of a PFA to TKA with the expectation of acceptable mid-term performance and survivorship, as long as congruent tracking with the new tibiofemoral components is achieved. This result is likely translatable to the majority of contemporary, all-polyethylene, dome-shaped patellar buttons, even with manufacturer mismatch.

Relation of MRI-Detected Features of Patellofemoral Osteoarthritis to Pain, Performance-Based Function, and Daily Walking: The Multicenter Osteoarthritis Study.

ObjectiveThe study objective was to determine the relationship of magnetic resonance imaging (MRI)‐detected features of patellofemoral joint osteoarthritis to pain and functional outcomes.MethodsWe sampled 1,099 participants from the 60‐month visit of the Multicenter Osteoarthritis Study (mean ± SD age: 66.8 ± 7.5 years; body mass index: 29.6 ± 4.8; 65% female). We determined the prevalence of MRI‐detected features of patellofemoral joint osteoarthritis (eg, cartilage damage, bone marrow lesions, and osteophytes) and assessed the relationship between these features and knee pain severity, knee pain on stairs, chair stand time, and walking less than 6,000 steps per day. We evaluated the relationship of MRI features to each outcome using logistic and linear regression, adjusting for potential covariates.ResultsParticipants with cartilage damage in 3‐4 subregions had the highest mean pain severity (22.0/100; 95% confidence interval [CI]: 17.6‐26.4 mm). They also showed higher odds of having at least mild pain on stairs (odds ratio [OR]: 3.3; 95% CI: 1.7‐6.5) and of walking less than 6,000 steps per day (OR: 2.3; 95% CI: 1.1‐4.4) compared with those without cartilage damage. Participants with bone marrow lesions in 3‐4 subregions had higher odds of at least mild pain on stairs than those without (OR: 3.3; 95% CI: 2.2‐5.2). Participants with osteophytes in 3‐4 subregions also had higher odds of walking less than 6,000 steps/day (OR 2.1, 95% CI: 1.3‐3.5, respectively).ConclusionMRI‐detected features of osteoarthritis of the patellofemoral joint are related to pain and functional performance. This knowledge highlights the need to develop treatments for those with patellofemoral joint osteoarthritis to improve pain and maximize function.

Management of patellofemoral joint osteoarthritis using biomechanical device therapy: a systematic review with meta-analysis

BackgroundCurrent clinical guidelines recommend conservative management including non-pharmacologic therapy prior to considering surgery for knee OA. There is a paucity of clinical trials investigating the use of biomechanical device therapies on those with patellofemoral joint osteoarthritis (PFJOA). The aim was to systematically review the effectiveness of biomechanical devices (bracing, taping, and footwear) in the management of symptomatic PFJOA.MethodThe Cochrane, PEDro, MEDLINE, CINAHL, AMED and EMBASE electronic databases were search from inception to October 31, 2020. Included studies were randomised controlled or clinical trials studying any form of biomechanical device therapy in the management of PFJOA in the English language. Studies included in the search were quality-appraised using the PEDro scoring system.ResultEleven studies were identified which included assessment of either patellar taping, or foot orthotics, knee bracing or combined physiotherapy treatments. Trial quality ranged from ‘poor’ through ‘fair’ to ‘good’. For patellar bracing, pooled analysis of two good quality randomised controlled trials showed no overall significant improvement on a visual analogue scale (VAS) (random effects (RE) standardised mean difference (SMD) = −0.42 (95%CI −1.12 to +0.29).Pooled data from the same two studies showed a non-significant improvement in favour of bracing assessed by the KOOS/WOMAC (RE SMD = −0.18 (95%CI −0.66 to +0.31). Two studies of ‘fair’ and ‘good’ quality applying patellar tape showed a significant reduction in pain immediately after application and after 4 days. A randomised trial of a foot orthotic showed a non-significant improvement in pain after 6 weeks with a between groups adjusted mean difference for maximum VAS of 21.9 mm (95% CI − 2.1 to 46.0) and 8.1 (95% CI− 6.9 to 23.1) for KOOS pain. A multimodal physiotherapy intervention (which included taping in two studies) showed a pooled significant improvement in VAS (SMD = −0.4; (95% CI −0.71 to −0.09) at 3 months compared to controls.ConclusionThere is some good quality evidence that a combined physiotherapy approach significantly reduces short-term pain in those with PFJOA. Long-term effects of all interventions are still unknown, which indicates the need for further research to determine the longer term impact of all biomechanical devices on outcomes in symptomatic PFJOA.