The aim of this study was to assess global data on patellofemoral arthroplasty (PFA) survival a decade after a prior investigation by Reihs et al. using the same endpoints and data sources, aiming to quantify potential changes in implant survival over this period. The hypothesis was that the pooled revision rate of contemporary PFA, quantified as revisions per 100 component-years (CY), would be lower than prior decade estimates derived from identical methodology and registry sources. A systematic search in Embase, MEDLINE and CENTRAL through October 2025 using a predefined search strategy was conducted using Ovid. Two reviewers screened and extracted data. The primary effect measure was revisions per 100 CY. Pooled estimates were obtained with fixed- and DerSimonian-Laird random-effects. Risk of bias was assessed with ROBINS-I. National arthroplasty registries meeting EAR/EUPHORIC Type A.1.1.1.1. criteria were analyzed. Fifteen primary studies were included, with most series using contemporary onlay designs. Per-study rates ranged from 0.355 to 3.400/100 CY. The pooled revision rate was 1.59/100 CY (95% confidence interval [CI] = 1.24-2.04) with random effects, corresponding to a 10-year revision rate of 15.9%, representing an absolute improvement of 6.3% in survivorship compared to the benchmark analysis by Reihs et al. heterogeneity was moderate (I2 = 52.7%). ROBINS-I indicated predominantly critical risk of bias. Registry synthesis (NJR, NZJR, AOANJRR, 117.524 CY) yielded 1.85/100 CY (95% CI = 1.775-1.931), corresponding to a 10-year revision rate of 18.5% (95% CI = 17.75-19.3) and an improvement of 0.4%-8.5% in the last decade if compared to Reihs et al. CONCLUSIONS: This meta-analysis demonstrates that modern PFA has a more favourable survivorship profile over the past decade, particularly with onlay designs. Proper patient selection and registry-based surveillance remain key to further optimization. Level IV.

Introduction:By tracking joint replacement implants, surgical techniques, and patient-reported outcomes, joint replacement registries are an important research and quality improvement tool. In the recent, history registries have identified early implant failures before government organizations such as the FDA. There is notable variability in the breadth and depth of information collected by joint replacement registries, and the goal of this study was to be the first to compare the major joint replacement registries around the world.Methods:Registries were identified from registry reports, publications, institutional records, and PubMed search. Registries were included in the study if there were publicly available reports summarizing the data contained in the registry. The annual report for each registry was reviewed for joint replacement volume of primary total hip arthroplasty, total knee arthroplasty, UKA, hip resurfacing, patellofemoral arthroplasty, revision total hip arthroplasty, and revision total knee arthroplasty. The presence or absence of numerous core registry features and additional registry features was identified for each registry.Results:The largest registries in cumulative joint replacement volume in descending order were as follows: National Joint Registry, American Joint Replacement Registry, Australian Orthopaedic Association National Joint Replacement Registry, Swedish Arthroplasty Register, Dutch Arthroplasty Register, Michigan Arthroplasty Registry Collaborative Quality Initiative, Norwegian Arthroplasty Register, and New Zealand Joint Registry. Australian Orthopaedic Association National Joint Replacement Registry, Swedish Arthroplasty Register, Michigan Arthroplasty Registry Collaborative Quality Initiative, and New Zealand Joint Registry have complete reporting on core registry features. American Joint Replacement Registry and Norwegian Arthroplasty Register provide near-complete reporting on the core registry features with only one feature partially reported. None of the registries have complete reporting of additional registry features such as use of robotics, surgeon-level data and reports, and external research access.Discussion:Despite the variability and the breadth of information contained in the worldwide registries, the information contained in these registries creates notable opportunities for the improvement of joint replacement surgery.

To evaluate the feasibility, radiological accuracy, and early clinical outcomes of robotic-assisted conversion of partial knee arthroplasty (PKA) to total knee arthroplasty (TKA) using the ROSA system. Feasibility was defined as successful robotic registration and completion of the procedure using standard primary components without femoral components or augments. A retrospective cohort of 23 consecutive conversions (medial or lateral unicompartmental and patellofemoral arthroplasties) was analyzed. The minimum follow-up was 12 months. Clinical outcomes were assessed with the Oxford Knee Score (OKS), visual analogue scale (VAS) for pain, and patient satisfaction. Radiological accuracy was evaluated by comparing planned with achieved component alignment (medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), and hip-knee-ankle (HKA)) using paired t-tests, two one-sided tests for equivalence (SD 1.5°), and Bland-Altman analysis. All cases were successfully registered with the robot and completed without femoral components or augments; 22 of 23 used standard primary components. The mean OKS improved from 17.2 (SD 5.5) to 40.0 (SD 5.0) and VAS pain decreased from 6.7 (SD 1.5) to 1.6 (SD 1.6) (p < 0.001). The mean absolute error between planned and achieved alignment was 0.8° for MPTA and 0.3° for LDFA, confirming accurate restoration, while HKA showed greater variability (mean bias 1.37°; limits -4.1° to 6.9°). One secondary patellar resurfacing was required; no other complications occurred. Robotic-assisted conversion of PKA to TKA was feasible, bone-preserving, and resulted in significant clinical improvement at 12 months, with precise component alignment but slightly more variation in overall mechanical axis restoration.

BackgroundTrochlea-only arthroplasty (TOA) is a conservative surgical approach for isolated patellofemoral arthritis, aimed at preserving the native patella and avoiding complications associated with its resurfacing. This study evaluates the mid-term survivorship, functional outcomes, and revision profile of patients undergoing TOA and compares outcomes with historical data from conventional patellofemoral arthroplasty (PFA).MethodsWe retrospectively reviewed 50 patients who underwent isolated TOA between 2008 and 2019 by a single surgeon. A medial parapatellar approach was used, with intraoperative assessment of the joint. The decision to retain the native patella was made irrespective of the extent of arthritis in the patella. All patients underwent patelloplasty and circum-patellar neurectomy without resurfacing. Implant survival was evaluated using Kaplan-Meier analysis, and factors influencing revision were assessed using Cox proportional hazards modelling. Patient-reported outcomes were collected using the Kujala score in a subset of patients with unrevised implants.ResultsThe overall implant survivorship was 82% at a mean follow-up of 9.2 years. Nine (18%) patients required revision, most commonly due to progression of tibiofemoral arthritis. Revisions included patellar resurfacing, staged medial unicompartmental knee replacement, and conversion to total knee arthroplasty. Age and sex were not significant predictors of revision. The mean Kujala score in 13 (32%) unrevised patients was 56.1, with no reports of instability or significant flexion deficits. No patients with known revisions were contacted for patient-reported outcomes.ConclusionTOA is a viable joint-preserving surgical option for selected patients with isolated patellofemoral arthritis. It avoids the complications associated with patellar resurfacing and maintains satisfactory mid-term survivorship comparable to published literature. TOA may serve as a procedural bridge between conservative management and full PFA, allowing for a stepwise and anatomically conservative approach. Further prospective studies are warranted to validate these findings.

Isolated patellofemoral osteoarthritis (PFOA) remains a therapeutic challenge, with patellofemoral arthroplasty (PFA) and total knee arthroplasty (TKA) representing the main surgical options for end-stage disease. This systematic review applies the GRADE framework to evaluate comparative outcomes of PFA and TKA, providing evidence-based recommendations. A PRISMA systematic search of Pubmed, Cochrane Library, and Google Scholar was conducted (2010–2025). RCTs, comparative cohort studies, and registry analyses reporting on PFA versus TKA for isolated PFOA were included. Primary outcomes were validated PROMs and implant survival at 2, 5, and 10 years. Secondary outcomes were complications, patient satisfaction, return to sport, and cost-effectiveness. Risk of bias was assessed with RoB 2 and ROBINS-I, and certainty of evidence using GRADE. Ten studies were included (4 RCTs, 6 cohort studies; approximately 10,000 PFAs comprising registries). Moderate-certainty evidence indicated that PFA provides superior early PROMs, and short-term cost-effectiveness compared with TKA. PROMs converged between groups at mid- to long-term follow-up. Long-term data demonstrated a consistently higher revision risk for PFA with moderate certainty, with registry-based 10-year survival of 85% for PFA vs. 95% for TKA, continuing to worsen for PFA after 10 years. Complication rates were similar or lower after PFA, particularly for systemic medical events. Patient satisfaction and return to sport favored PFA short term but became comparable to TKA at mid-term. In carefully selected patients with isolated PFOA, modern onlay PFA yields faster recovery, superior early function, and short-term cost-effectiveness, supported by moderate-certainty evidence. These advantages are offset by a higher long-term revision risk compared with TKA, highlighting the need to inform patients of this trade-off. TKA remains the reference standard for patients with tibiofemoral disease or instability, supported by high-certainty evidence, and offers durable, predictable long-term outcomes in more heterogeneous patient populations. Systematic GRADE (Grading of Recommendations, Assessment, Development and Evaluation) review of RCTs and observational studies.

Can Robotic-Assisted Arthroplasty Change the High Early Revision Rate After Patello-femoral Arthroplasty? An Analysis From the Australian Orthopaedic Association National Joint Replacement Registry.

Impact of Age on Patello-femoral Arthroplasty Outcomes, Osteoarthritis Progression, and Survivorship: The Youngest and Oldest Achieve the Best Results.

The aim of this study was to assess the implant survival and patient-reported outcome measures of robotic arm-assisted patellofemoral arthroplasty (raPFA) and to define patient-acceptable symptom state (PASS) thresholds. A multicentre retrospective cohort study of 112 raPFA was undertaken. The mean age of the patients was 63.3 years (21 to 89), and 88 (78.6%) were female. Oxford Knee Score (OKS), Kujala score, EuroQol five-dimension questionnaire (EQ-5D), EuroQol-visual analogue scale (EQ-VAS), Net Promoter Score (NPS), and patient satisfaction were assessed. Mean follow-up was 3.3 years (1.0 to 7.7). There were four reoperations (three revisions) during the follow-up period. The four-year survival was 94.4% (95% CI 89.9 to 98.9) for all-cause reoperation, 96.7% (95% CI 94.5 to 100) for all-cause revision, and 97.7% (95% CI 93.8 to 100) for aseptic revision. A total of 79 (76.0%), 62 (59.6%), 67 (64.4%), and 49 (54.4%) knees achieved the PASS thresholds in the OKS, Kujala, EQ-5D, and EQ-VAS scores, respectively. The satisfaction rate was 77.9% (n = 81) and the NPS was 59.7. Increasing American Society of Anesthesiologists (ASA) grade (odds ratio 0.02, 95% CI 0.00 to 0.22, p = 0.001) was independently associated with dissatisfaction. The OKS (area under the curve (AUC) 89.1, 95% CI 82.5 to 95.8) and Kujala score (AUC 86.1, 95% CI 77.7 to 94.5) were excellent, and the EQ-5D (AUC 75.4, 95% CI 61.7 to 89.1) and EQ-VAS (AUC 76.7, 95% CI 64.0 to 89.5) were acceptable discriminators of satisfaction, with PASS thresholds of 36, 72, 0.710, and 74, respectively. Using these new thresholds, the number achieving a PASS decreased in the OKS (n = 75; 72.1%), increased in the Kujala score (n = 73; 70.2%) and EQ-VAS (n = 58; 64.4%), and remained identical for the EQ-5D. raPFA was associated with clinically meaningful postoperative outcome measures and a high NPS. However, approximately one in five were not satisfied, which was independently associated with increasing comorbidity, and approximately one in 20 underwent reoperation in the first four years postoperatively. The defined PASS thresholds specifically for PFA could be used to help interpret outcomes in future studies.

Robotic arm-assisted (RA) surgery is associated with improved accuracy and outcomes in medial unicompartmental knee arthroplasty, but the role in patellofemoral arthroplasty (PFA) remains less well defined. This review aimed to evaluate the functional outcomes and implant survivorship of RA-PFA. A systematic review of PubMed, Embase and the Cochrane Library was performed in November 2025. All studies reporting clinical outcomes for RA-PFA were included. The primary outcome was survival at final follow-up; secondary outcomes included patient-reported outcomes, reoperation frequency and radiographic outcomes. Meta-analyses of survival and nonconversion reoperation rates, and comparative analyses with other PFA techniques were performed. Eight studies (893 patients; 72.4% female, mean age 56.6 years [SD 7.7]) assessing RA-PFA were included. Survivorship was 93.6% (95% confidence interval [CI]: 91.2-95.8) at a mean follow-up of 3.3 years (SD 1.1). Meta-analysis of studies comparing survivorship of RA-PFA (n = 713) with manual PFA (n = 1580) showed reduced risk of revision for RA-PFA (RR = 0.75, 95% CI = 0.562-0.995, p = 0.048). The wide CI indicate uncertainty around the estimate. No survivorship difference was observed between robotic techniques. No randomised studies were identified. Reporting of PROMs following RA-PFA was limited to three studies (n = 112), all of which demonstrated excellent postoperative functional outcomes, with only one assessing postoperative health-related quality of life. Radiological outcomes and implant positioning were reported in only two studies (n = 66): one reporting improvements in patellar tilt compared with manual PFA following RA-PFA, comparable to other robotic systems, and one reported strong correlations between implant positioning and preoperative templating. RA-PFA achieves good short-term survivorship and functional outcomes that are comparable to manual techniques. However, the small number of available studies, short follow-up and lack of randomised trials preclude definitive conclusions. Level IV, systematic review and meta-analysis.

BackgroundIsolated patellofemoral joint arthritis with patellar malalignment in young patients presents a unique challenge, as these patients typically wish to avoid early total knee arthroplasty. The purpose of this retrospective case series is to describe a standardized dual-surgeon technique for combined patellofemoral arthroplasty (PFA) with patellar realignment using medial patellofemoral ligament reconstruction or tibial tubercle osteotomy and to evaluate early clinical and patient-reported outcomes.MethodsA retrospective review was conducted on patients who underwent combined PFA and patellar realignment by a fellowship-trained arthroplasty surgeon and fellowship-trained sports surgeon. Outcomes including implant survivorship, functional outcomes, complications, and patient-reported measures (Knee Injury and Osteoarthritis Outcome Score Joint Replacement, Patient Reported Outcomes Measurement Information System (PROMIS), Global Physical Health, PROMIS Global Mental Health, and Forgotten Joint Score) were assessed.ResultsEleven knees in 9 patients were included (55.5% female; median age 41 ± 13.4 years; median body mass index 26 ± 6.2). All knees had isolated patellofemoral arthritis. Nine knees underwent PFA with medial patellofemoral ligament reconstruction for instability or dislocation, while 2 underwent PFA with tibial tubercle osteotomy for patella alta. Two patellae were chronically dislocated, additionally requiring lateral release. Six knees had prior failed stabilizing procedures. The mean operative time was 121 minutes (94–161), with a mean follow-up of 24.0 ± 11.5 months. One patient experienced a periprosthetic patellar fracture at 10 months, followed by a refracture at 14 months, requiring open reduction and internal fixation and extensor mechanism repair. No cases of re-dislocation, maltracking, infections, wound complications, or other medical issues occurred. Knee Injury and Osteoarthritis Outcome Score Joint Replacement scores improved by an average of 14.8 ± 11 points.ConclusionsCombined PFA and patellar realignment surgery can be done efficiently and is associated with improved patient-reported outcomes, with complications limited to a single case of periprosthetic patellar fracture.

Patellofemoral osteoarthritis (PFOA) substantially impairs quality of life, and isolated patellofemoral arthroplasty (PFA) is a surgical option for therapy-refractory symptoms. This study evaluated the clinical and functional outcomes and survivorship of an onlay PFA implant, hypothesizing favourable results in the mid- to long-term follow-up. Between 2009 and 2023, 128 knees (123 patients) with PFOA underwent onlay PFA (Journey™ PFJ, Smith & Nephew) and were retrospectively analyzed. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Short Form-12 (SF-12) and the numerical analog scale (NAS) for pain and function were assessed preoperatively and at the final follow-up. Postoperative complications and revisions were recorded. Follow-up data were available for 91 knees (88 patients; mean age 60.7 ± 10.3years) over 6.1 ± 3.4years. Significant improvements in the WOMAC total score (57.3% to 22.5%; p < 0.001), SF-12 physical (29.6 to 43.5; p < 0.001) and mental scores (46.8 to 52.7; p < 0.001), and NAS function (4.7 to 7.2; p < 0.001) and pain (7.8 to 3.1; p < 0.001) were observed. Patients who did not achieve the minimal clinically important difference (MCID) had higher preoperative WOMAC scores (61.3% vs. 46.0%; p = 0.018). The SF-12 mental component summary (MCS) scores was correlated with the pre- and postoperative WOMAC scores (r2 = 0.21-0.32; p ≤ 0.002). Kaplan-Meier analysis revealed PFA survivorship rates of 89%, 75%, and 67% at five, ten and 15years, respectively. Onlay PFA provides significant and sustained improvements in pain, function, and quality of life in patients with PFOA, with satisfactory mid- to long-term implant survivorship. A high preoperative WOMAC score and poor mental health, as indicated by the SF-12 MCS, may be associated with less favourable postoperative outcomes.

Patellofemoral arthroplasty (PFA) is a joint-sparing alternative to total knee arthroplasty (TKA) for isolated patellofemoral osteoarthritis, offering symptom relief while preserving tibiofemoral compartments and bone stock compared with TKA, particularly in younger and active patients. However, persistent anterior knee pain and patellar instability remain the leading causes of early failure, even when prosthetic components are stable and tibiofemoral degeneration is absent. This study aimed to describe a combined, nonprosthetic surgical strategy for symptomatic PFA failure due to patellar instability and to propose an algorithm-based framework for clinical decision-making. A 54-year-old woman presented with chronic anterior knee pain and recurrent instability four years after isolated PFA. Imaging confirmed stable and well-aligned prosthetic components with preserved tibiofemoral compartments but consistent lateral patellar subluxation. The patient was treated using a joint-preserving approach combining medial patellofemoral ligament (MPFL) reconstruction with hamstring autograft, anteromedial tibial tubercle osteotomy (TTO), and vastus medialis obliquus (VMO) advancement. Clinical outcomes were assessed with the Kujala and International Knee Documentation Committee (IKDC) scores at six weeks and three months. At three months, the Kujala score improved from 54 to 78, and the IKDC subjective score increased from 38 to 69. The patient reported significant pain reduction, restoration of patellar stability, and functional recovery. No recurrent instability, surgical complications, or implant-related problems were observed. Radiographs confirmed correct alignment and congruent prosthetic components. A combined approach addressing soft-tissue, bony, and dynamic stabilizers may provide an effective, joint-preserving alternative to TKA in selected patients with symptomatic PFA failure caused by instability. The algorithm presented may assist in surgical decision-making and optimize patient outcomes. V.

Excellent Short-Term Outcomes After Kinematic Alignment, Medial-Pivot Total Knee Arthroplasty for Isolated Patellofemoral Osteoarthritis

Therapeutic effects of patellofemoral arthroplasty (PFA) on patellofemoral arthritis are presented. All patellofemoral arthroplasties performed from 2008 to 2023 were retrospectively reviewed using case notes, radiographs and clinic appointments until their latest follow-up period. 132 arthroplasties in 126 patients were followed up for an average period of 31.8 months (range 3–90 months). The average age was 54.2 years with 112 female patients and 14 male patients. No severe complications were detected during follow-up period. Knee function: straight 0°, flexion average 120° (110 to 135°). Feller score was 24.8 points (22 to 28 points). Arthroplasty is required when conservative treatments were ineffective. Although total knee arthroplasty (TKA) has achieved good results in the treatment of tricompartment osteoarthritis, there is still controversy over the treatment of pure patellofemoral arthritis. PFA has minimal trauma, good clinical efficacy, less osteotomy, and more preservation of tibiofemoral joint bone mass, without affecting possible future TKAs. This surgical procedure has satisfactory mid-term efficacy, but close follow-up is needed for its long-term efficacy.

Spin Is Prevalent in the Majority of Abstracts of Patello-femoral Arthroplasty Studies.

Patellofemoral arthroplasty (PFA) is an established treatment for isolated patellofemoral osteoarthritis. However, evidence regarding postoperative activity levels and return to sport (RTS) remains limited. The objective of this study was to evaluate RTS and recreational activity rates following PFA, identify factors influencing these outcomes, and report associated complications. A systematic search was conducted in June 2024 across PubMed, EMBASE, ScienceDirect, and Scopus databases, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Search terms included variations of "patellofemoral arthroplasty," "physical activity," and "return to sport." Studies were included if they reported RTS outcomes following PFA. Studies lacking RTS data or isolated PFA results were excluded. From 492 records, 7 studies met the inclusion criteria. Seven studies (2 prospective and 5 retrospective) comprising 265 patients (281 knees; 64.6% women; mean age: 48.9 years) were included, with a mean follow-up of up to 5.3 years. RTS definitions varied, with reported rates ranging from 64.7% to 91%. Low-impact sports were more commonly resumed, and 58.6% of patients returned to sport within six months. Among those who returned, 74.8% reached or exceeded their preoperative activity level. Postoperative pain improved (visual analog scale scores decreased from 6.3 to 2.7), although up to 38.6% of patients reported pain limiting activity. Conversion to total knee arthroplasty occurred in 6.3% to 13% of cases, and reoperation rates ranged from 10.4% to 25%. Limitations included inconsistent RTS definitions, heterogeneous outcome reporting, and use of non-standardized questionnaires. RTS and recreational activity after PFA can be resumed by most patients, especially low-impact activities. Pain management should be actively addressed. High-quality studies with standardized RTS definitions are needed to evaluate the long-term impact of activity on implant survival. RTS after PFA is safe and achievable. A personalized approach is essential to optimize RTS and manage patient expectations. III.

PurposeIsolated patellofemoral osteoarthritis (PFOA) is a degenerative condition, typically presenting as anterior knee pain. For patients who are refractory to conservative treatment, patellofemoral arthroplasty (PFA) is a viable surgical option. Appropriate patient selection is fundamental to achieving favourable long‐term outcomes. Large multicenter and registry studies have reported outcomes of PFA (under 0.45%–2% utilization). Howevever, because of the heterogenicity of indications and surgeons, those findings may not be transferable to individual surgeon practices. This study aimed to evaluate the utilization and long‐term survival of PFA within a high‐volume, single‐surgeon arthroplasty practice.MethodsThis retrospective study included consecutive cases of Patellofemoral arthroplasties performed between 2012 and 2014. Patients with prior ipsilateral knee surgery, patellar instability, or less than 10 years of follow‐up were excluded. The number of primary knee arthroplasties performed within the same period was collected. Radiographic assessments included Kellgren–Lawrence grading, Iwano grading, Insall‐Salvati ratio, Dejour classification, medial proximal tibial angle, joint line convergence angle, sulcus angle and anatomical lateral distal femoral angle. Implant survival rates were evaluated over a 10‐year follow‐up period.ResultsA total of 37 patients (50 patellofemoral arthroplasties) who underwent PFA for isolated PFOA were included, alongside 2556 primary knee arthroplasties. PFAs accounted for 2.0% of the primary knee arthroplasties performed during the study period. All patients were classified as Iwano grade IV preoperatively. The 10‐year survival rate was 86.0%. All seven PFA failures were due to progression of tibiofemoral osteoarthritis and were converted to total knee arthroplasty.ConclusionsPFA demonstrated a 10‐year implant survival rate of 86.0% when performed under strict selection criteria in a high‐volume arthroplasty centre. Achieving optimal outcomes requires careful patient selection, surgical proficiency and alignment with patient expectations. Further prospective studies are warranted to better evaluate long‐term functional outcomes after PFA.Level of EvidenceLevel III, retrospective cohort study.

Background: The morphometry of the patella serves as a critical guide in understanding the biomechanics of the knee joint, the pathophysiology of knee disorders, gender determination, the design of patellar implants, and patellar reconstruction procedures. Aims and Objectives: This study aims to collect morphometric data on the patella in the Turkish population and to analyze these findings in relation to gender, laterality, and age. Materials and Methods: This retrospective study was conducted on computed tomography images of the knee joints from 426 patellas (141 males, 72 females) aged 20–89. Patellar parameters were measured and compared according to gender and laterality. In addition, three age groups were formed to investigate age-related differences. Results: Patellar height (PH), width, thickness, medial facet width, lateral facet width (LFW), and facet thickness were significantly greater in males. In contrast, the patellar medial facet ratio, patellar lateral facet ratio (PLFR), and patellar relative thickness were significantly higher in females. A significant difference in the PLFR was observed between the right and left sides. Furthermore, PH, thickness, and LFW exhibited significant differences across the age groups. Conclusions: The findings from this study are expected to prove valuable in procedures such as total knee arthroplasty, patellofemoral arthroplasty, prosthesis design, and enriching local anthropological records.

Calcium pyrophosphate dihydrate (CPPD) deposition, often visible radiographically as chondrocalcinosis, frequently accompanies knee osteoarthritis and is usually encountered at the time of arthroplasty. Whether its presence influences the outcome of patellofemoral arthroplasty (PFA) remains uncertain. We reviewed 100 PFAs performed in 82 patients between 1997 and 2005, and followed them for an average of 22 years (range, 20-25 years). At surgery, 35 knees showed radiographic chondrocalcinosis, and an additional 33 developed calcification during follow-up. Fifteen knees (15%) required revision to total knee arthroplasty (TKA) at a mean of 12 years after PFA. The main reasons for revision were tibiofemoral osteoarthritis progression (6 knees), patellar malalignment (7 knees), one implant loosening, and one patella fracture. The 20-year survival rates were 87% for knees without chondrocalcinosis and 90% for those with chondrocalcinosis, with no significant difference in revision timing between groups (log-rank p = 0.64). Although chondrocalcinosis became more prevalent with age and follow-up, it did not increase the risk of conversion to TKA. These findings suggest that PFA remains a suitable option in carefully selected patients, regardless of the presence of chondrocalcinosis.

PurposeIsolated patellofemoral arthritis is a well-recognized variant of knee osteoarthritis. The cause of isolated patellofemoral arthritis can be traumatic, secondary to malalignment, degenerative, or idiopathic. This study aims to evaluate whether the results of our third-generation patellofemoral arthroplasty (PFA) support its continued use as a viable treatment option for isolated patellofemoral arthritis.MethodsA retrospective cohort study was conducted using the electronic NHS trust database to identify all patients who underwent PFA between September 2008 and April 2014. Each patient was subsequently reviewed at our outpatient clinic, where they completed a series of standardized questionnaires to assess treatment outcomes. These included the Short Form 12v2, the Forgotten Joint Score (FJS), the Kujala Score, and the Knee Injury and Osteoarthritis Outcome Score (KOOS). A total of 44 patellofemoral joints (PFJs) were included in the study.ResultsFour patients required revision surgery to convert their PFJ replacement to a total knee replacement. Additionally, three patients underwent arthroscopy for the management of patella maltracking. When asked about their satisfaction and whether they would choose to undergo the same surgery again, only seven patients indicated that they would opt for the procedure again. The FJS revealed that the majority of patients (85%) reported being rarely or never aware of their artificial joint in daily activities. The average Kujala score was found to be 4, reflecting moderate discomfort or dysfunction levels. The KOOS indicated that most patients experienced mild to moderate symptoms, with occasional bouts of pain and moderate stiffness. Importantly, the KOOS findings also suggested that the patients’ daily activities were not severely impacted.ConclusionPFJ arthroplasty can yield positive outcomes for younger patients who suffer from isolated patellofemoral arthritis. However, achieving successful results is heavily influenced by the careful and appropriate selection of patients rather than the choice of the implant itself.