Patellofemoral Arthroplasty: Current Concepts and Review of the Literature

Patello-femoral arthroplasty- indications and contraindications

Patellofemoral arthroplasty (PFA) is emerging as an attractive alternative to total knee arthroplasty (TKA) for isolated patellofemoral-osteoarthritis (PF-OA) for selected patients. The success of PFA is highly dependent on patient selection. This intervention is still burdened with a higher rate of revisions and a lower survival rate than TKA when the indications or the surgical technique are not optimal. We highlight the indications and contraindications of PFA to obtain satisfying functional outcomes and survivorship. Preoperative clinical and radiological assessment is critical to determine the presence of PFA indications, the absence of contraindications and the necessity of any associated procedures, particularly for the tibial tubercle. The typical indications are patients with isolated symptomatic PF-OA, with trochlear dysplasia, when bone-on-bone Iwano 4 osteoarthritis is observed, without significant malalignment and with the absence of risk factors for developing progressive tibiofemoral-OA. The three main causes of isolated PF-OA are primary OA, trochlear dysplasia and posttraumatic OA following patellar fracture. Trochlear dysplasia is the preferred indication for PFA. Lack of experience with arthroplasty or realignment of the extensor mechanism is a relative contraindication to performing PFA.

Unicompartmental knee replacement: controversies and technical considerations

BACKGROUND

Unicompartmental knee replacement (UKR) is one of the effective interventions for the treatment of symptomatic knee osteoarthritis. Moreover, it has multiple advantages over total knee arthroplasty (TKA), including reduced intraoperative blood loss, decreased risk of transfusion, and faster recovery. This study aimed to discuss critical technical considerations regarding UKR and some of the controversies and updates.

METHODS

We conducted a review to provide an overview of the controversies and technical considerations about UKR in several aspects. Only peer-reviewed articles were included, up to December 2023 using PubMed, Google Scholar, ERIC, and Cochrane database for systematic reviews databases.

RESULT

UKR is associated with superior patient-reported clinical and functional outcomes, as well as shorter hospital stays, fewer postoperative complications, and revealed favorable outcomes in patients' return to sport. The choice between mobile- and fixed-bearing prostheses depends, in part, on the surgeon's preference. The mobile-bearing UKR is a less constrained prosthesis and can potentially result in less wear, but it is more technically demanding. While no significant difference between mobile-bearing versus fixed-bearing prostheses, cementless is superior to cemented design. Furthermore, UKR can be a good alternative for high tibial osteotomy (HTO) and still can be considered after a failed HTO. Lastly, recent reviews have shown a revision rate comparable to that of TKA. This is probably influenced by Improved comprehension of the best indications, patient selection criteria, as well as of the design, materials, and technological advances.

CONCLUSION

UKR treatment for unicompartmental knee osteoarthritis is secure and effective. Based on clinical and functional outcomes, decreased morbidity and mortality, and cost-effectiveness, long-term studies suggest that UKR is superior to TKA. Further investigation in this area is warranted.

Regional Trends in Unicondylar and Patellofemoral Knee Arthroplasty: An Analysis of the American Joint Replacement Registry

BACKGROUND

As the popularity of unicondylar knee arthroplasty (UKA) and patellofemoral arthroplasty (PFA) have expanded, more patients who have limited arthritis are undergoing partial knee arthroplasty. No studies have evaluated if any regional differences in the United States (U.S.) exist between partial versus total knee arthroplasty (TKA). The purpose of this study was to utilize the American Joint Replacement Registry to evaluate regional differences in UKA, PFA, and TKA.

METHODS

The American Joint Replacement Registry was queried for all TKA, PFA, and UKA procedures between 2012 and 2021. Surgical volume was compared between the Midwest (MW), Northeast (NE), South, and West (W) regions. Trends were compared using multivariate logistic regression analyses and least squared mean logistic regression models.

RESULTS

Since 2012, there has been a steady increase in the amount of UKAs performed across the U.S., except during the COVID-19 pandemic when numbers decreased. Logistic regression analyses demonstrated a higher likelihood of receiving a UKA compared to TKA in the NE compared to other regions, and higher likelihood of receiving a PFA in the NE and W compared to other regions over the study period. Other factors that increased the likelihood of having a UKA nationally were men, the procedure being performed at a teaching hospital, and having surgery in urban areas. Patients were more likely to have a PFA in the NE compared to the S and MW, and higher odds in the South and W compared to the MW, with rates of PFA consistently lower in the MW compared to other regions.

CONCLUSIONS

Patients were more likely to have a UKA in the NE compared to other regions of the country. Patients had higher odds of having a PFA in the NE and W regions relative to the MW. Men had higher odds of having either UKA or PFA than women across the nation.

Current outcomes of patellofemoral arthroplasty for isolated patellofemoral arthritis - A narrative review

Patellofemoral (PFJ) arthritis can be primary, or secondary to underlying trochlea dysplasia and patellofemoral malalignment. Although primary PFJ osteoarthritis affects an older patient population, just like tibiofemoral arthritis, it is common for younger patients to present with isolated PFJ arthritis secondary to an abnormal PFJ. PFJ arthroplasty (PFJA) has many benefits including being less invasive, associated with lower blood loss, is more cost-effective, and leaves the kinematics of the tibiofemoral joint undisturbed. As a result, there are arguably better functional outcomes associated with PFJA, however the historical revision rate of this procedure is high. Although registry outcome data associated with the first generation of PFJ implants shows a higher revision rate compared to TKA, the comparison of PFJ outcomes with TKA is not always age-matched and there is limited comparison on functional and patient-reported outcomes, something which is more important and relevant in a younger patient cohort. Improvements in implant design, instrumentation, surgical technique, and better patient selection has now resulted in outcomes which are comparable to that of TKA, and in some cases even better. This narrative review outlines the current outcomes of PFJA including highlighting factors which need to be considered in optimising outcomes, as well as discussing advanced techniques of robotic assisted PFJA.

Using expletives to enhance therapeutic outcomes: A case report

Background

Swearing deserves attention in the physical therapy setting due to its potential positive effects on pain, physical performance, and therapeutic alliance. The purpose of this case report is to describe the strategic use of swearing in the clinical setting.

Case Presentation

A 44-year-old female completed an episode of physical therapy after undergoing patellofemoral arthroplasty. Swearing was formally included into the plan of care, and the patient swore out loud during the most challenging and painful interventions.

Results

The patient reported that repeating a swear word was funny, distracted the patient, and made the patient feel more confident. The patient and physical therapist self-reported a strong therapeutic alliance.

Conclusion

There is evidence repeating a swear word out loud can strengthen the therapeutic alliance, improve physical performance, and decrease pain. This is, to our knowledge, the first report of a patient swearing during an episode of physical therapy care.

Patellofemoral arthroplasty with onlay prosthesis leads to higher rates of osteoarthritis progression than inlay design implants: a systematic review

PURPOSE

The aim of this study was to report the clinical and functional outcomes, complication rates, implant survivorship and the progression of tibiofemoral osteoarthritis (OA), after new inlay or onlay patellofemoral arthroplasty (PFA), for isolated patellofemoral OA. Comparison of different implant types and models, where it was possible, also represented one of the objectives.

METHODS

A systematic literature search following PRISMA guidelines was conducted on PubMed, Scopus, Embase and Cochrane databases, to identify possible relevant studies, published from the inception of these databases until 11.11.2022. Randomized control trials (RCTs), case series, case control studies and cohort studies, written in English or German, and published in peer-reviewed journals after 2010, were included. Not original studies, case reports, simulation studies, systematic reviews, or studies that included patients who underwent TKA or unicompartmental arthroplasty (UKA) of the medial or lateral compartment of the knee, were excluded. Additionally, only articles that assessed functional and/or clinical outcomes, patient-reported outcomes (PROMs), radiographic progression of OA, complication rates, implant survival rates, pain, as well as conversion to TKA rates in patients treated with PFA, using inlay or onlay trochlea designs, were included. For quality assessment, the Methodological Index for Non-Randomized Studies (MINORS) for non-comparative and comparative clinical intervention studies was used.

RESULTS

The literature search identified 404 articles. 29 of them met all the inclusion criteria following the selection process. Median MINORS for non-comparative studies value was 12.5 (range 11-14), and for comparative studies 20.1 (range 17-24). In terms of clinical and functional outcomes, no difference between onlay and inlay PFA has been described. Both designs yielded satisfactory results at short, medium and long-term follow-ups. Both designs improved pain postoperatively and no difference between them in terms of postoperative VAS has been noted, although the onlay groups presented a higher preoperative VAS. When comparing the inlay to onlay trochlea designs, the inlay group displayed a lower progression of OA rate.

CONCLUSION

There is no difference in functional or clinical outcomes after PFA between the new inlay and the onlay designs, with both presenting an improvement in most of the scores that were used. A higher rate of OA progression was observed in the onlay design group.

LEVEL OF EVIDENCE

III.

Modern Patellofemoral Arthroplasty

INTRODUCTION

The ideal procedure for isolated patellofemoral arthritis is a controversial topic. Patellofemoral arthroplasty (PFA) is an option that aims to restore normal kinematics to the knee while preserving bone. PFA has been shown to have benefits compared with total knee arthroplasty (TKA) in this patient population but has historically had a high failure rate. Revision rates are improving with modern implants and tight indications but still remain higher than TKA. This review summarizes current thinking around PFA using modern implants and techniques in 2023, provides an implant-specific analysis, and assesses how we can improve outcomes after PFA based on the current literature. The aim was to provide an outline of the evidence around PFA on which surgeons can make decisions to optimize patient outcome in this young and active population.

METHODS

Four databases (MEDLINE, Embase, Scopus, and SPORTDiscus) were searched for concepts of patellofemoral joint arthroplasty. After abstract and text review, a screening software was used to assess articles based on inclusion criteria for studies describing indications, outcomes, and techniques for isolated PFA using modern implants, with or without concomitant procedures.

RESULTS

A total of 191 articles were included for further examination, with 62 articles being instructional course lectures, systematic reviews, technique articles, narrative reviews, expert opinions, or meta-analyses. The remaining articles were case reports, trials, or cohort studies. Articles were used to create a thorough outline of multiple recurrent topics in the literature.

CONCLUSIONS

PFA is an appealing option that has the potential to provide a more natural feeling and functioning knee for those with isolated PF arthritis. The high rate of revision is a cause for concern and there are several technical details that should be stressed to optimize results. The uncertain outcome after revision to TKA also requires more investigation. In addition, the importance of strict selection criteria and firm indications cannot be stressed enough to optimize longevity and attempt to predict those who are likely to have progression of tibiofemoral osteoarthritis. The development of new third-generation implants is promising with excellent functional outcomes and a much lower rate of maltracking and implant complications compared with earlier generations. The impact of these implants and improvement in surgical techniques on the revision rate of PFA will be determined from longer-term outcomes.

Midterm outcomes of patellofemoral arthroplasty

BACKGROUND

The purpose of this study is the evaluation of the patellofemoral arthroplasty (PFA) survival and clinical and radiological outcomes in our institution.

METHODS

A retrospective evaluation of our institution patellofemoral arthroplasty cases from 2006 to 2018 was performed; the n sample after applying exclusion and inclusion criteria was 21. All patients excepting one were female with a median age of 63 (20-78). A Kaplan-Meier survival analysis at ten years was calculated. Informed consent was obtained from all patients prior being included in the study.

RESULTS

The total revision rate was 6 out of 21 patients (28.57%). The progression of the osteoarthritis in the tibiofemoral compartment was the main cause (50% of revision surgeries). The degree of satisfaction with the PFA was high, with a mean Kujala score of 70.09 and a mean OKS of 35.45 points. The VAS score improved significantly (P<.001) from a preoperative mean of 8.07 to a postoperative mean of 3.45, with an average improvement of 5 (2-8). Survival at 10 years, with revision for any reason as the endpoint, was 73.5%. A significant positive correlation between BMI and the WOMAC pain (r=.72, P<.01) and between BMI and the post-operative VAS (r=.67, P<.01) was observed.

CONCLUSIONS

The results of the case series under consideration suggest that PFA could be a possibility in the joint preservation surgery on the isolated patellofemoral osteoarthritis. BMI >30 seems to be a negative predictor factor in relationship with the postoperative satisfaction, increasing the pain proportionally to this index and requiring more replacement surgery than patients with BMI <30. Meanwhile the radiologic parameters of the implant are not correlated with the clinical or functional outcomes.

A Narrative Review of Patellar Resurfacing Versus Non-resurfacing in Total Knee Arthroplasty

The number of individuals who experience the symptoms of gonarthrosis rises proportionally as life expectancy rises and the population becomes more active. The purpose of total knee arthroplasty (TKA) is to lessen pain and restore knee function, and it has a high success rate. The restoration of patellar tracking in addition to the proper alignment of the femoral and tibial components contributes to the success of the arthroplasty and the patient's happiness. Replacement of the knee is not an easy process. One of the major objectives of total knee replacement is to achieve the proper rotation of the femoral components. A critical step that affects postoperative outcomes in total knee arthroplasty is the correct alignment of the femoral component. The axial plane of the femoral component is to blame for flexion stability, knee joint kinematics, flexion alignment, and patellar tracking. The patella is the largest sesamoid bone in the human body, and its major role is to enhance the quadriceps' moment arm, which allows the knee to expand. The distribution of patellofemoral compressive pressures during knee flexion and the centralization of the quadriceps muscles' multidirectional pull during extension are both critical functions of the patella. After primary knee arthroplasty, there are 8% more cases of anterior knee discomfort than there were before. Whether or not the patella was resurfaced, patients with primary TKA experience anterior knee discomfort. Patella baja is caused by excessive joint line elevation, which causes persistent overload and discomfort. The design of the TKR might have an impact on postoperative patellofemoral problems. After TKR, patellofemoral maltracking and patellar dislocation are often caused by surgical mistakes.

Patient-Reported Outcomes and Risk Factors for Decreased Improvement after Patellofemoral Arthroplasty

Patellofemoral arthroplasty (PFA) is acknowledged as the method for the treatment of isolated patellofemoral osteoarthritis (PFOA). Few previous studies have assessed the patient-reported outcomes (PROs) and risk factors of less improvement of PROs in patients undergoing PFA. A retrospective analysis was performed, including all patients who had undergone PFA. Pre- and postoperative PROs included the Oxford Knee Score (OKS) and Kujala score. Univariate and multivariate statistical analyses were performed to assess influencing factors of less improvement of PROs including the demographic factors (gender, age, body mass index, smoking, opioid usage, and duration of symptoms [DOSs]), surgical factors (concomitant surgery), and imaging factors (trochlear dysplasia [TD], patellar height, the degree of PFOA). A total of 46 PFAs were analyzed with a mean follow-up of 37 ± 7 months. The mean age at surgery was 61.1 ± 7.7 years. Patients showed significant improvement in all PROs (p < 0.001). Patients with TD preoperatively have greater improvement in OKS and Kujala score postoperatively (19.2 ± 5.0 vs. 23.1 ± 3.6, p = 0.038). Longer DOSs (≥1 year) had a greater mean improvement in OKS and Kujala score (p = 0.011 and p = 0.000). According to the measurement of patella height, patients with patella alta (Caton-Deschamps index [CDI] ≥1.3) showed less improvement in both OKS and Kujala score (p = 0.000 and p = 0.002). PFA is a safe and efficient surgery with good PROs. Patella alta with a CDI ≥1.3 and duration of preoperative symptoms ≤ 1 year were risk factors for decreased OKS and Kujala score improvement, while the preoperative presence of TD was significantly predictive factors for increased OKS improvement.

A standardized technique for lateral unicompartmental knee arthroplasty

OBJECTIVES

We developed a new standardized procedure for lateral unicompartmental knee arthroplasty (UKA) to maximize the benefits and minimize the risks of surgery in patients with osteoarthritis (OA).

METHODS

This retrospective study recruited patients who underwent lateral UKA at our hospital between January 2014 and January 2016. Demographic characteristics and preoperative and postoperative American Knee Society (AKS) clinical scores (including pain, clinical, and knee mobility scores) were collected.

RESULTS

A total of 158 patients (35 male and 123 female) who underwent 160 lateral UKAs were analyzed. Their AKS clinical scores (0-100 points) improved from 53.1 ± 4.1 (range 45-62) preoperatively to 97.0 ± 1.7 (range 92-99) (p < 0.001) postoperatively with additional improvements of 9.1 ± 1.8 (range 3-14) to 47.3 ± 1.5 (range 45-49) (p < 0.001) for pain, 49.7 ± 9.7 (range 35-70) to 97.1 ± 4.1 (range 90-100) (p < 0.001) for function, and 105.0 ± 4.4° (equivalent to ∼100-115°) to 125.5 ± 5.3° (∼110-135°) (p < 0.001) for a range of motion (ROM). No patients required reoperations or revisions. Two patients were readmitted within 60 days due to severe knee swelling.

CONCLUSION

The lateral UKA protocol was reproducible and the patients had a good postoperative outcomes. Yet, large-scale, multi-center, prospective studies are needed to further confirm our findings.

Midterm outcomes of patellofemoral arthroplasty

BACKGROUND

The purpose of this study is the evaluation of the patellofemoral arthroplasty (PFA) survival and clinical and radiological outcomes in our institution.

METHODS

A retrospective evaluation of our institution patellofemoral arthroplasty cases from 2006 to 2018 was performed; the n sample after applying exclusion and inclusion criteria was 21. All patients excepting one were female with a median age of 63 (20-78). A Kaplan-Meier survival analysis at ten years was calculated. Informed consent was obtained from all patients prior being included in the study.

RESULTS

The total revision rate was 6 out of 21 patients (28.57%). The progression of the osteoarthritis in the tibiofemoral compartment was the main cause (50% of revision surgeries). The degree of satisfaction with the PFA was high, with a mean Kujala score of 70.09 and a mean OKS of 35.45 points. The VAS score improved significantly (p<0.001) from a preoperative mean of 8.07 to a postoperative mean of 3.45, with an average improvement of 5 (2-8). Survival at 10 years, with revision for any reason as the endpoint, was 73.5%. A significant positive correlation between BMI and the WOMAC pain (r=0.72, p<0.01) and between BMI and the post-operative VAS (r=0.67, p<0.01) was observed.

CONCLUSIONS

The results of the case series under consideration suggest that PFA could be a possibility in the joint preservation surgery on the isolated patellofemoral osteoarthritis. BMI >30 seems to be a negative predictor factor in relationship with the postoperative satisfaction, increasing the pain proportionally to this index and requiring more replacement surgery than patients with BMI <30. Meanwhile the radiologic parameters of the implant are not correlated with the clinical or functional outcomes.

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

BACKGROUND

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.

METHODS

A review of the Embase, Cochrane and PubMed databases was performed following PRISMA search principles.

RESULTS

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.

CONCLUSION

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.

Older age and varus alignment lead to early failure in treating patellofemoral osteoarthritis with Fulkerson osteotomy

Background: It is unclear the risk factors for the failure of modified Fulkerson osteotomy. Methods: We retrospectively reviewed 40 patients who underwent the modified Fulkerson osteotomy from 1998 to 2015. There were 4 males and 36 females. The mean age of the study group was 50.2 ± 11.2 years. We used standard anteriorization measuring 10-15 mm and medialization measuring 10 mm while maintaining an intact periosteal sleeve. Results: Both the patellofemoral angle and the congruence angle improved significantly after 5.9 years. Preoperatively, the mean preoperative Lysholm score was 56.12, and the Knee Society score was 60.52. At the final follow-up, these scores improved significantly to 88.75 and 86.49, respectively. However, eight patients (20%) underwent total knee arthroplasty in the follow-up period, five of whom underwent the operation within 5 years. Comparing the survival and non-survival groups, there was a significant difference of an older age in the TKA conversion group (survival: 48.3 ± 11.1; non-survival: 57.8 ± 8.7, p = 0.03). For knee alignment, the non-survival group had a mean valgus femorotibial angle of 1.8° ± 4.9° preoperatively, and the survival group had a mean valgus angle of 6.4° ± 4.5° (p = 0.03). Conclusions: we found that patients with older age and those with varus alignment have an increased risk of deteriorated medial femorotibial cartilage.

Management of Chondral Defects Associated with Patella Instability

Cartilage defects of the patellofemoral joint are commonly found in association with patellar instability owing to abnormal biomechanics. Strategies to address chondral defects of the patellofemoral joint secondary to instability should first address causes of recurrent instability. Most patellofemoral chondral defects associated with instability are less than 2 cm2 and do not generally require intervention beyond chondroplasty. Larger defects of the patella and/or the trochlea can be repaired with osteochondral or surface cartilage repair.

The short-term effectiveness and safety of second-generation patellofemoral arthroplasty and total knee arthroplasty on isolated patellofemoral osteoarthritis: a systematic review and meta-analysis

Background

We aimed to compare second-generation patellofemoral arthroplasty (2G PFA) with total knee arthroplasty (TKA) in treating isolated patellofemoral osteoarthritis (PFOA) by assessing the percentages of revisions, complications, and patient-reported outcome measures (PROMs).

Methods

Studies that compared the outcomes of 2G PFA and TKA in the treatment of isolated PFOA were searched in electronic databases, including MEDLINE, Embase, and Web of Science. Two researchers independently identified eligible studies, extracted the data, and evaluated the quality of the literature. Pooled risk ratios (RRs) or weighted mean differences with 95% confidence intervals were calculated using either fixed or random effects models. Descriptive analysis was used when data could not be pooled.

Results

A total of six studies were included in the review. For the revision percentage and complications, there were no significant differences between 2G PFA and TKA (RR = 2.29, 95% CI 0.69–7.58, P = 0.17; RR = 0.56, 95% CI 0.23–1.40, P = 0.22, respectively). Second, the results demonstrated that the differences in the Oxford Knee Score (OKS) and the University of California, Los Angeles (UCLA) activity score between 2G PFA and TKA were not significant (WMD −4.68, 95% CI −16.32 to 6.97, p = 0.43; WMD 0.16, 95% CI −1.21 to 1.53, P = 0.82). The Knee Injury and Osteoarthritis Outcome Score (KOOS), the American Knee Society Score (AKSS), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were presented in a narrative form due to methodological heterogeneity.

Conclusion

For isolated PFOA, 2G PFA demonstrated similar results to TKA with respect to the percentages of revisions, complications, and PROMs.

[Patellofemoral inlay implants-an innovation in patellofemoral joint arthroplasty?]

Isolated arthrosis of the patellofemoral joint is a rare and complex disease. After conservative therapy has been exhausted, the orthopedist has various soft-tissue and bone reconstructive procedures as well as cartilage regenerative procedures at his hands. In cases of failed or unsatisfactory therapy, patellofemoral arthroplasty continues to be controversially discussed as an alternative therapy. A closer look at these studies reveals promising results with the correct indication and patient selection. The different prosthesis designs provide good postoperative results while considering general and specific risks. The current generation of patellofemoral inlay prostheses shows high patient satisfaction with significant improvements in knee function and pain relief in mid-term outcomes. However, a relatively high revision rate must be considered.

[Expert consensus on surgical treatment of patellofemoral osteoarthritis]

Patellofemoral osteoarthritis (PFOA) is one of the most common causes of anterior knee pain in middle-aged and elderly population. In general, elementary therapy and drug therapy are the preferred choices for PFOA management. However, for those who cannot achieve satisfactory effectiveness with standard non-surgical treatment, surgical therapy stands as an alternative treatment. The surgical therapy includes repair surgery and reconstruction surgery. The choice of surgical plans for PFOA management mainly depends on the etiology, pathogenesis, location, and severity of the lesions. To aid clinical decision-making, the National Clinical Research Center for Geriatric Disorders (Xiangya Hospital) and the Joint Surgery Branch of the Chinese Orthopedic Association arranged nationwide orthopedic specialists to set up a work panel. After reviewing the research progress of surgical therapy and the latest guidelines and consensus for PFOA management, the work panel discussed repeatedly to reach this consensus. The present consensus aims to provide valid evidences for clinical practices of the surgical therapy of PFOA, so as to avoid inappropriate and irregular treatment behaviors, reduce surgical trauma, improve surgical efficacy and the quality of life, and to ease the burden of PFOA.

Smoking, unemployment, female sex, obesity, and medication use yield worse outcomes in patellofemoral arthroplasty

PURPOSE

The purpose of this study was to identify effects of psychosocial and demographic factors on patellofemoral arthroplasty (PFA) outcomes.

METHODS

Patients who underwent PFA by a single surgeon between 2002 and 2013 (min. 2 year follow-up) were included. Knee Society scores (KSS), UCLA, and Tegner Scores were prospectively collected in a designated arthroplasty registry. Patient records were retrospectively reviewed and univariate and multivariate statistical analyses were performed to assess the effect of psychosocial factors and demographic variables including patient sex, BMI, smoking and medication use, psychiatric history, and employment status on improvement between pre- and post-operative scores.

RESULTS

Seventy-four knees in 55 patients (88% female) with a mean age of 51.8 (SD 8.8) and mean follow-up of 46.5 (SD 26.9) months were included. Patients showed significant improvement in all functional outcomes (p < 0.001). Mean improvement in KSS-F scores and median improvement in Tegner scores was greater in males compared to females (37.8 vs 16.1, p = 0.007; 3.0 vs 2.0, p = 0.07, respectively). Smokers showed less improvement in KSS-P compared to non-smokers (17.2 vs 30.0, p = 0.028). Retired or employed patients had a greater mean improvement in KSS-F and median improvement in Tegner Scores compared to those were unemployed or on work disability (p = 0.022, p = 0.01). Patients who reported using opioids and/or anti-depressants pre-operatively showed less improvement in UCLA scores (p = 0.006). Obese patients showed less improvement in both KSS-F and Tegner score compared to non-obese patients (p = 0.009, p = 0.004).

CONCLUSION

Psychosocial factors influence the degree of improvement following PFA. Although patients showed overall improvement compared to their baseline scores, obese patients, smokers, unemployed/work disabled, and pre-operative use of opioids and/or anti-depressants were risk factors for decreased improvement… The consideration of psychosocial variables are clinically important when assessing a patient's candidacy for PFA and improve pre-operative patient selection and counselling.

LEVEL OF EVIDENCE

Level IV.

The midterm results of a cohort study of patellofemoral arthroplasty from a non-designer centre using an asymmetric trochlear prosthesis

PURPOSE

Patellofemoral arthroplasty (PFA) prosthesis with asymmetric trochlear component was introduced as an improvement from existing designs for surgical treatment of symptomatic isolated patellofemoral arthritis. The purpose of this study was to evaluate midterm results in patients who underwent PFA procedure using such prosthesis.

METHODS

Our study involved a continuous retrospective cohort of patients who underwent PFA using Journey PFA prosthesis with an asymmetric trochlear component, performed between June 2007 and July 2016 at a non-designer centre. The Patient Reported Outcome Measures and patient satisfaction questionnaires were collected for final evaluation.

RESULTS

A total of 103 PFA performed on 79 patients were evaluated. Median age at the time of surgery was 58years (range 42 to 78years); the mean follow-up period was 6 years (range 2 to 11years). Four knees were revised to Total Knee Arthroplasty for reasons not related to the implant. The cumulative survival estimated by the Kaplan-Meier method was 94.3% (95% confidence interval: 88.4%-100%). There were statistically significant improvements in functional outcome scores.

CONCLUSION

This series of patients who underwent PFA with the asymmetric trochlear component has shown promising mid-term results with no implant-related complications.

The patient results and satisfaction of knee arthroplasty in a validated grading system

INTRODUCTION

The validated Knee Osteoarthritis Grading System (KOGS) was implemented and clinical results were compared with patient satisfaction data and implant survivorship in a multi-centre study with surgeons familiar with unicompartmental knee arthroplasty (UKA), patellofemoral arthroplasty (PFA) and total knee arthroplasty (TKA). This is also the first study to evaluate the prevalence of UKA and TKA in consecutive osteoarthritis (OA) knee arthroplasties assessed by this system..

METHOD

A consecutive cohort of knees was gathered at three different institutions as categorized by KOGS and surgically treated with the recommended implant unless clinical reasons or patient preference precluded such an option. One thousand one hundred seventy-seven consecutive knees were evaluated including 311 TKA (26%), 695 medial UKA (59%), 154 lateral UKA (13%) and 17 PFA (2%) and the results of the categories evaluated with the Oxford Knee Score (OKS) and the complications reflected in the different categories.

RESULTS

The failure rate of the UKA (3.5%) or TKA (1.6%) is not higher than accepted results in the literature and the difference in complications is negligible between the UKA (72%) and TKA (26%) cohorts. Revision of a UKA to a TKA as an endpoint was 0.58% with ipsilateral progression at 0.8% over a period of five to 84 months (mean follow-up of 36 months) despite the 'excessive' proportion of UKA in this cohort. The Oxford Score improvement is significant in TKA and UKA and contributes to the acceptable outcomes (The OKS for TKA improved from 20 pre-operatively to 36 post-operatively and the UKA improved from 22 pre-operatively to 39 post-operatively).

CONCLUSION

KOGS achieves acceptable early survival and functional results when implemented and is a suitable tool for identifying the preferred implant as was validated.

High patient satisfaction with significant improvement in knee function and pain relief after mid-term follow-up in patients with isolated patellofemoral inlay arthroplasty

PURPOSE

To prospectively evaluate the clinical and radiographic outcomes and survivorship at 2 and 5 years after isolated contemporary patellofemoral inlay arthroplasty.

METHODS

Thirty-four patients were prospectively enrolled in the study and were evaluated preoperatively and at 2 and 5 years postoperatively. Clinical outcomes included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and the visual analogue scale (VAS) for pain. Kellgren-Lawrence grading was used to assess the progression of tibiofemoral osteoarthritis and the Caton-Deschamps Index to determine patellar height. A Kaplan-Meier survival analysis was used to investigate the implant survivorship. Preoperative patient characteristics were compared among failures and success to determine potential risk factors and patient satisfaction was rated postoperatively.

RESULTS

Five of the 34 patients were lost to follow-up resulting in a final follow-up rate of 86%. The total WOMAC subscores of pain and function and the VAS Pain improved significantly at 2- and 5-years, with no significant difference between the two time points. The WOMAC stiffness subscale reached significant improvement at 2-year follow-up alone. No significant progressions of tibiofemoral arthritis or changes in patellar height were observed. A total of six patients (17.1%) failed leaving a survival rate of 91% after 2 years and 83% after 5 years. The main cause for postoperative failure was persistent knee pain; however, no significant preoperative risk factor in patient characteristics could be identified.

CONCLUSION

Patellofemoral inlay arthroplasty shows high patient satisfaction with significant improvement in knee function and pain relief after mid-term follow-up with no radiographic progression of tibiofemoral OA.

LEVEL OF EVIDENCE

Prospective case series, Level III.