Mid-Term Clinical, Functional, and Radiographic Outcomes of 105 Gender-Specific Patellofemoral Arthroplasties, With or Without the Association of Medial Unicompartmental Knee Arthroplasty

Outcomes of isolated patellofemoral arthroplasty

Osteoarthritis of the patellofemoral compartment can cause significant functional impairment. Isolated patellofemoral osteoarthritis affects greater than 10% of males and females over the age of 60. Patellofemoral arthroplasty (PFA) was developed as a joint-preserving procedure that maintains natural knee kinematics in those with isolated patellofemoral disease. First-generation implants were fraught with complications, a high rate of revision, and early conversion to total knee arthroplasty (TKA). Second-generation implants have demonstrated significant improvements in patient-reported outcome measures, complication rates and implant survivorship. Factors that can affect outcomes include surgical indications, patient selection, and PFA prosthesis design. Modern PFA for isolated patellofemoral osteoarthritis has comparable outcomes to TKA for isolated patellofemoral osteoarthritis. In this article, we discuss the use of PFA, implant design, the indications and factors affecting outcomes, and comparison to TKA.

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.

The Influence of Patello-Femoral Overstuffing After Modular Unlinked Bicompartmental Knee Arthroplasty (BiKA) for Medial Tibio-Femoral and Patello-Femoral Osteoarthritis of the Knee

BACKGROUND

The factors affecting results after bicompartmental knee arthroplasty (BiKA) have not been fully elucidated. This major ligament-preserving procedure may be more susceptible to overstuffing of the patello-femoral (PF) joint than the major ligament-sacrificing total knee arthroplasty. Currently, we investigated the effect of PF overstuffing after BiKA on its clinical outcome.

METHODS

There were 71 patients (74 knees) who underwent modular unlinked BiKA at our clinic who had a follow-up of 5 to 9 years. Final follow-up results were assessed by evaluating knee range of motion, the 2011 Knee Society Score (2011KSS), Japanese Knee Osteoarthritis Measure, and radiological findings. The degree of postoperative PF overstuffing was evaluated by computed tomography and magnetic resonance images for 55 knees, and the correlation between the degree of overstuffing and postoperative clinical results were examined.

RESULTS

Overall clinical results improved significantly after surgery without any revision cases. The X-ray measurements showed the improved coronal alignments and the appropriate implant installation angles. Higher degree of postoperative PF overstuffing caused by insufficient amount of osteotomy on the anterior surface of the femur correlated with worse postoperative total 2011KSS at 2 years after surgery (Spearman's rank correlation coefficient (rs) = -0.387, P = .004), as opposed to no correlation at the time of the final follow-up (Spearman's rank correlation coefficient = 0.068, P = .623).

CONCLUSION

Modular unlinked BiKA provided patients with a high level of satisfaction and functional improvement over 5 to 9 years postoperatively. However, because PF overstuffing affects initial patient satisfaction, the amount of osteotomy should be determined carefully during the surgery.

One-Stage Tricompartmental Hypoallergenic UKA for Tricompartmental Osteoarthritis: A Case Report

Osteoarthritis (OA) is a degenerative and progressive joint disease. When all three compartments are involved, end-stage OA is treated with a total knee arthroplasty (TKA). Unicompartmental knee arthroplasty (UKA) is a primary treatment for isolated osteoarthritis. UKA has a quicker recovery time than TKA, as well as less morbidity and more tissue sparing. At the time of surgery, 17% of patients have a tricompartmental disease and most patients with a Kellegren-Lawrence grade >3 have an intact anterior cruciate ligament (ACL). Conventional TKA sacrifices the ACL. Patients with concurrent medial and lateral osteoarthritis and a functional ACL may receive a primary bi-unicondylar arthroplasty. Combined partial knee arthroplasty (CPKA) is an established practice either in bicompartmental femoro-tibial OA or in OA progression after UKA, with the addition of another UKA. A conversion of a lateral UKA to a tricompartmental joint replacement has been reported in the literature. In our case report, we describe a one-stage hypoallergenic tricompartmental UKA, with improved clinical score and no sign of early failure at the last follow-up.

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.

Outcomes and complications of inlay versus onlay patellofemoral arthroplasty: A systematic review

PURPOSE

The purpose of this systematic review was to evaluate outcomes and complications rates between inlay and onlay patellofemoral arthroplasty (PFA).

METHODS

According to the PRISMA statement, 42 studies with 2552 patients were included. Data considered for quantitative analysis consisted of the Knee Society Score (KSS), the range of motion (ROM), the visual analogue score (VAS), and the Western Ontario and McMaster Universities questionnaire (WOMAC). Complications and revision surgery were considered.

RESULTS

Data on postoperative KSS showed no differences between the groups. The ROM was evaluated in 8 studies for 70 and 331 inlay and onlay PFA, respectively. Onlay group was favorable in terms of postoperative ROM. Postoperative VAS was available for 64 inlay and 110 onlay and no differences were found. Data on postoperative WOMAC were available for 49 inlay and 527 onlay PFA and inlay group showed better scores. A statistically significant higher rate of instability, persistent pain, malposition, stiffness, deep infection, disease progression, and wear of the patellar component were noted in the inlay group. A higher rate of lateral release was noted in the onlay group. A higher number of manipulations under anesthesia was noted in the inlay group. The revision to total knee arthroplasty was reported more frequently in the inlay group.

CONCLUSION

A higher rate of conversion to total knee arthroplasty and complication rates after inlay technique was found. The potential of achieving better WOMAC scores with the inlay technique should be weighed against the higher complication and revision rates compared to the onlay technique.

LEVEL OF EVIDENCE

IV.

Better PROMs and higher return-to-sport rate after modular bicompartmental knee arthroplasty than after total knee arthroplasty for medial and patellofemoral compartment osteoarthritis

Background

Theoretical advantages of bicompartmental knee arthroplasty (BKA) over total knee arthroplasty (TKA) for bicompartmental (medial combined with patellofemoral) osteoarthritis (OA) are still unclear. This study aimed to compare patient-reported outcome measures (PROMs) and return-to-sport (RTS) rate between modular BKA and TKA in early follow-up.

Methods

Twenty-five consecutive modular BKA cases with a minimum 2-year follow-up were matched with 50 TKA cases at 1:2 ratio. Demographic data and preoperative functional scores, including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Knee Society Scores (KSSs), were analyzed to ensure comparability. Postoperative WOMAC score, KSS, range of motion (ROM), Forgotten Joint Score-12 (FJS-12), and RTS rates were compared. Operative time and blood loss were also analyzed.

Results

Significant differences in the WOMAC-function (median 97.1 vs. 89.7, p < 0.001) and KSS-function (median 90.0 vs. 80.0, p = 0.003) scores were identified between the BKA and TKA groups. ROM was significantly greater in the BKA group than in the TKA group (median 125.0° vs. 120.0°, p = 0.004), in addition to the FJS-12 (median 89.6 vs. 53.1, p < 0.001). The overall RTS rate was significantly higher in the BKA group than in the TKA group (71.6% vs. 56.5%, p = 0.039). Operative time was significantly longer in the BKA group than in the TKA group (median 105.0 vs. 67.5 min, p < 0.001), but blood loss was similar (median 557.6 vs. 450.7 ml, p = 0.334).

Conclusion

Modular BKA demonstrated better functional recovery, better joint perception, and higher RTS rate than TKA; thus, modular BKA can be a good alternative for bicompartmental OA.

Patellofemoral arthroplasty: obesity linked to high risk of revision and progression of medial tibiofemoral osteoarthritis

PURPOSE

The purpose of this study was to determine the effect of obesity on patient outcome, procedure failure rate and osteoarthritis (OA) progression in the tibiofemoral compartments in a series of isolated patellofemoral arthroplasty (PFA) performed with a third-generation implant.

METHODS

The study population was patients who had undergone third-generation PFA at a specialized orthopedic center between 2007 and 2017. Patients were categorized by body-mass index (BMI) as obese (O, BMI > 30 kg/m²) or nonobese (NO, BMI < 30 kg/m²). Preoperative and postoperative clinical and functional assessment included knee range of motion, Knee Society Score (KSS), University of California Los Angeles (UCLA) Activity Score, Tegner Activity Level Scale, and visual analogue scale (VAS) for pain. Preoperative and postoperative radiographs were evaluated for progression of tibiofemoral compartment OA, changes in patellar height and in knee coronal alignment. Multiple logistic regression models were used to assess the effect of BMI on outcomes together with other covariates.

RESULTS

A total of 120 PFAs with a mean follow-up of 6.9 ± 2.5 years were included: 25 in the O group and 95 in the NO group. Significant improvement was noted in in knee range of motion (P < 0.001), clinical and functional KSS (P < 0.001), UCLA Activity Score (P < 0.001), Tegner score (P < 0.001) and VAS pain (P < 0.001) without inter-groups differences. Worsening of the medial Kellgren-Lawrence (KL) grade (but not the lateral KL grade) was more frequent in the O than the NO group during the follow-up period (P = 0.014). Failure occurred in 4.2% of NO and in 20% of O group patients; the difference was solely due to failure because of OA progression in the tibiofemoral compartment (16% in the O group). There were no between group differences in the failure rate for any cause other than OA progression (4.2% in the NO group, 4.0% in the O group).

CONCLUSIONS

An equal improvement in function after PFA was noted in both obese and nonobese patients; however, the high failure rate due to OA progression in the medial tibiofemoral compartment warrants caution when considering PFA in obese patients.

Patellofemoral arthroplasty in combination with high tibial osteotomy can achieve good outcome for patients with medial-patellofemoral osteoarthritis

Background

The purpose of our study is to report on the clinical outcomes of patients who undergoing patellofemoral arthroplasty (PFA) in combination with a high tibial osteotomy (HTO). Due to this procedure's conservative and kinematics-preserving characteristics, we hypothesized that PFA in combination with HTO would result in good clinical outcomes in patients with medial and patellofemoral compartment osteoarthritis (MPFOA).

Methods

Patients who underwent PFA in combination with HTO for MPFOA from January 2018 to April 2020 were included in the study. Clinical outcomes were analyzed by comparing the Knee Society Score, Oxford Knee Score, Range of Motion, and Forgotten Joint Score before and after the procedure. Radiological evaluations were also performed to assess the tibiofemoral osteoarthritis progression and implant loosening. For all tests, the value of p < 0.05 was considered statistically significant.

Results

A total of nine consecutive patients who underwent PFA in combination with HTO were included. Two were males, seven were females. The average follow-up period was 2.6 ± 0.4 years. Clinical outcomes showed a significant improvement in the Knee Society Score (clinical score: 90.3 ± 8.5 and function score: 90.8 ± 7.8), Oxford Knee Score (43.6 ± 3.6), Forgotten Joint Score (71.2 ± 10.2), and knee Range of Motion (130.4 ± 8.1°) at the final follow-up. Additionally, hip-knee-ankle angle significantly decreased from -9.3 ± 2.1° preoperatively to 2.2 ± 1.2° at the final follow-up (p < 0.05). There were no complications for any patient during the follow-up time.

Conclusion

This study shows that patients who underwent PFA in combination with HTO for the treatment of MPFOA achieved good clinical and radiological outcomes. This combined surgery could be an effective alternative to treat MPFOA in well-selected patients.

Combined procedures with unicompartmental knee arthroplasty: High risk of stiffness but promising concept in selected indications

Introduction: Unicompartmental knee arthroplasty (UKA) has traditionally been contraindicated in the presence of an ACL deficient knee, bi-compartmental disease, or significant coronal deformity due to concerns regarding increased risk of persisted pain, knee instability, tibial loosening, or progression of osteoarthritis. The aim of this study was to evaluate the outcomes of patients undergoing UKA with an associated surgical procedure in these specific indications. Method: This was a retrospective cohort study of patients undergoing UKA between December 2015 and October 2020. Patients were categorized into groups based on associated procedures: UKA + ACL, UKA + HTO, and bicompartmental arthroplasty. Outcomes were assessed using the Knee Society Score (KSS) knee and function scores and the Forgotten Joint Score. Radiological and complication analysis was performed at the last clinical follow-up. Results: Thirty-two patients (13 men and 19 women) were included. The mean age was 56.2 years ± 11.1 (range, 33–84) with a mean follow-up of 26.3 months ± 15 (7.3–61.1). There was a significant improvement between the pre-and postoperative KSS Knee (+34.3 ± 16.5 [12–69]), Function (+34.3 ± 18.6 [0–75]), and Total scores (+68.5 ± 29.4 [24–129]) (p = 0.001). Seven patients (21.8%) required an arthroscopic arthrolysis for persistent stiffness. Two patients (UKA + PFA and UKA + ACL) underwent revision to TKA. Patient satisfaction was 90%, and mean flexion at last follow-up was 122° ± 6 (120–140). The implant survival rate was 94%. Discussion: This study found performing UKA with an additional procedure to address relative contraindications to the arthroplasty in physically active patients with monocompartmental knee arthritis is an efficient strategy with good results at short-term follow-up. It should be reserved for patients where TKA is likely to have unsatisfactory results, and the patient has been fully counseled regarding the management options. Even if there is a high rate of complications with stiffness requiring a re-intervention, the final results are very satisfying with no impact of the reintervention on the clinical result in the short term.

Robotic-arm assisted bicompartmental knee arthroplasty: Durable results up to 7-year follow-up

BACKGROUND

The purpose of our study was to investigate the mid-term clinical and functional outcomes of robotic-arm assisted Bicompartmental knee arthroplasty (BiKA).

METHODS

This study reviewed a single-centre prospectively maintained cohort of 50 patients (53 knees) who underwent BiKA (patellofemoral and medial compartment) at 5- and 7-year postoperative follow-up.

RESULTS

Mean follow-up was 7.1 ± 0.1 years (range, 7.0-7.3). Kaplan-Meier survivorship rates at 5 and 7 years were 96% and 93%, respectively. At 7-year follow-up, patient satisfaction was 76% satisfied, 13% neutral, and 11% not satisfied. Mean KSS-FS was 80.5 ± 15.8 (range, 30-100) with 82% of patients reporting walking more than 10 blocks, 89% reporting walking without support, and 100% able to go up and down stairs with 61% requiring use of a rail. Three patients (four knees) underwent revision surgery.

CONCLUSIONS

Our study reported excellent survivorship and functional outcomes, and good-excellent satisfaction at mid-term follow-up for robotic-arm assisted BiKA.

Does bicompartmental knee arthroplasty hold an advantage over total knee arthroplasty? Systematic review and meta-analysis

INTRODUCTION

The role of bicompartmental knee arthroplasty (BKA) in the treatment of medial patellofemoral osteoarthritis (MPFOA) has been debated by orthopaedic surgeons for years. The BKA is a cruciate ligament retaining prosthesis designed to mimic the kinematics of the native knee that requires resurfacing of only two knee compartments. In this study, we aim to assess the patient recorded outcome measures (PROMs), range of motion (ROM), perioperative morbidity, and implant revision rate in patients undergoing BKA and compare them to those undergoing total knee arthroplasty (TKA) for bicompartmental knee osteoarthritis (OA).

PATIENTS AND METHODS

We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses Statement (PRISMA). Articles from any country and written in any language were considered. We included all randomized control trials and retrospective cohort studies examining BKA versus TKA for bicompartmental knee OA. The primary outcome measure was knee society score (KSS) at one year and the secondary outcome measures were Oxford knee score (OKS) and short-form survey (SF-)12 at six and twelve months.

RESULTS

We included five studies in our meta-analysis. In terms of OKS, KSS, and SF-12, our meta-analysis suggests better short-term results for the TKA compared with the BKA. TKA was also associated with a shorter operative time and a lower revision rate. The BKA implant did however result in marginally less intraoperative blood loss and slightly better post-operative ROM.

CONCLUSIONS

BKA did not prove to be an equivalent alternative to TKA in bicompartmental knee OA. It was associated with inferior KSS, OKS, and SF-12 at short-term follow-up and a higher revision rate.

Onlay Patellofemoral Arthroplasty in Patients With Isolated Patellofemoral Arthritis: A Systematic Review

BACKGROUND

Patellofemoral arthroplasty (PFA) for isolated patellofemoral osteoarthritis (OA) remains controversial due to variable postoperative outcomes and high failure rates. Second-generation (2G) onlay prostheses have been associated with improved postoperative outcomes. This systematic review was performed to assess the current overall survivorship and functional outcomes of 2G PFA.

METHODS

A search was performed using PubMed, Cochrane Library, EMBASE, and Google Scholar. Thirty-three studies published in the last 15 years (2005-2020) were included; of these 22 studies reported patient-reported outcome measures. Operative and nonoperative complications were analyzed. Pooled statistical analysis was performed for survivorship and functional scores using Excel 2016 and Stata 13.

RESULTS

The mean age of the patients was 59.7. When analyzing all studies, weighted survival at mean follow-up of 5.52 was 87.72%. Subanalysis of studies with minimum 5 years of follow up showed a survival of 94.24%. Fifteen studies reported Oxford Knee Score with a weighted mean postoperative Oxford Knee Score of 33.59. Mean American Knee Society Score pain was 79.7 while mean American Knee Society Score function was 79.3. The most common operative complication was OA progression for all implants. The percentage of revisions and conversions reported after analyzing all studies was 1.37% and 7.82% respectively.

CONCLUSION

Safe and acceptable results of functional outcomes and PFA survivorship can result from 2G PFAs at both short and mid-term follow-up for patients with isolated patellofemoral OA. However, long-term follow-up outcomes are still pending for the newer implants. More extensive studies using standardized functional outcomes and long-term cost benefits should be evaluated.

Mid- to long-term follow-up of combined small implants

AIMS

In the last decade, interest in partial knee arthroplasties and bicruciate retaining total knee arthroplasties has increased. In addition, patient-related outcomes and functional results such as range of movement and ambulation may be more promising with less invasive procedures such as bicompartmental arthroplasty (BCA). The purpose of this study is to evaluate clinical and radiological outcomes after a third-generation patellofemoral arthroplasty (PFA) combined with a medial or lateral unicompartmental knee arthroplasty (UKA) at mid- to long-term follow-up.

METHODS

A total of 57 procedures were performed. In 45 cases, a PFA was associated with a medial UKA and, in 12, with a lateral UKA. Patients were followed with validated patient-reported outcome measures (Oxford Knee Score (OKS), EuroQol five-dimension questionnaire (EQ-5D), EuroQoL Visual Analogue Scale (EQ-VAS)), the Knee Society Score (KSS), the Forgotten Joint Score (FJS), and radiological analysis.

RESULTS

The mean follow-up was nine years (6 to 13). All scores significantly improved from preoperatively to final follow-up (mean and SD): OKS from 23.2 (8.1) to 42.5 (3.5), EQ-5D from 0.44 (0.25) to 0.815 (0.1), EQ-VAS from 46.7 (24.9) to 89.1 (9.8), KSS (Knee) from 51.4 (8.5) to 94.4 (4.2), and KSS (Function) from 48.7 (5.5) to 88.8 (5.2). The mean FJS at final follow-up was 79.2 (4.2). All failures involved the medial UKA + PFA group. Overall, survival rate was 91.5% for all the combined implants at ten years with 95% confidence intervals and 22 knees at risk.

CONCLUSION

Excellent clinical and radiological outcomes were achieved after a third-generation PFA combined with a medial or lateral UKA. BCA with unlinked partial knee prostheses showed a good survival rate at mid- to long-term follow-up. Cite this article: Bone Joint J 2021;103-B(5):840-845.

Tibial Osteolysis After Long-Term Isolated Polyethylene Patellar Resurfacing

Isolated patellar resurfacing served as an early treatment for patellofemoral arthritis but was abandoned because of erosion of the native femoral trochlear groove over time. We present the case of a large native tibial osteolytic lesion 20 years after isolated patellar resurfacing with a cemented polyethylene component. The patient had severe tricompartmental arthritic changes. The patellar component was very worn, and the resultant particle debris produced a large cavitary lesion in the proximal tibia. Osteolysis is a rare complication in patellofemoral arthroplasty, and, to our knowledge, this is the first reported case of native tibial osteolysis after isolated patellar resurfacing. The patient was treated with initial curettage and bone grafting of the lesion followed by total knee arthroplasty with a tibial cone and stemmed tibial fixation.

Risk factors for pain and functional impairment in people with knee and hip osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

To identify risk factors for pain and functional deterioration in people with knee and hip osteoarthritis (OA) to form the basis of a future 'stratification tool' for OA development or progression.

DESIGN

Systematic review and meta-analysis.

METHODS

An electronic search of the literature databases, Medline, Embase, CINAHL, and Web of Science (1990-February 2020), was conducted. Studies that identified risk factors for pain and functional deterioration to knee and hip OA were included. Where data and study heterogeneity permitted, meta-analyses presenting mean difference (MD) and ORs with corresponding 95% CIs were undertaken. Where this was not possible, a narrative analysis was undertaken. The Downs & Black tool assessed methodological quality of selected studies before data extraction. Pooled analysis outcomes were assessed and reported using the Grading of Reccomendation, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

82 studies (41 810 participants) were included. On meta-analysis: there was moderate quality evidence that knee OA pain was associated with factors including: Kellgren and Lawrence≥2 (MD: 2.04, 95% CI 1.48 to 2.81; p<0.01), increasing age (MD: 1.46, 95% CI 0.26 to 2.66; p=0.02) and whole-organ MRI scoring method (WORMS) knee effusion score ≥1 (OR: 1.35, 95% CI 0.99 to 1.83; p=0.05). On narrative analysis: knee OA pain was associated with factors including WORMS meniscal damage ≥1 (OR: 1.83). Predictors of joint pain in hip OA were large acetabular bone marrow lesions (BML; OR: 5.23), chronic widespread pain (OR: 5.02) and large hip BMLs (OR: 4.43).

CONCLUSIONS

Our study identified risk factors for clinical pain in OA by imaging measures that can assist in predicting and stratifying people with knee/hip OA. A 'stratification tool' combining verified risk factors that we have identified would allow selective stratification based on pain and structural outcomes in OA.

PROSPERO REGISTRATION NUMBER

CRD42018117643.

Systematic Review of Modular Bicompartmental Knee Arthroplasty for Medio-Patellofemoral Osteoarthritis

BACKGROUND

We aimed to locate, appraise, and synthesize the available literature to assess the functional outcome of modular bicompartmental knee arthroplasty (BKA) compared to total knee arthroplasty (TKA) for medio-patellofemoral osteoarthritis.

METHODS

After an extensive literature search based on electronic databases such as MEDLINE, EMBASE, CINAHL, and PubMed, and grey literature, 9 articles satisfied our selection criteria which included 1 randomized controlled trial, 1 prospective cohort, 3 retrospective cohort, and 4 case series. Narrative synthesis was performed due to clinical, methodological, and statistical heterogeneity among the included studies.

RESULTS

There were 331 participants (341 knees) in this systematic review. BKA group included 229 patients (239 knees) and TKA group included 102 patients (102 knees). The quality of included studies ranged from moderate to very low as per GRADE (grading of recommendations, assessment, development, and evaluation working group) score with low to high risk of bias. Most of the studies showed comparable functional outcome in BKA compared to TKA such as Knee Society Score, Knee Osteoarthritis and Outcome Score, Short Form-36 score, and revision surgery in short-term to midterm follow-up. BKA patients achieved better range of movement and forgotten knee status than TKA patients. It resulted in longer operative time, but less intraoperative blood loss. Long-term series showed 95.1% survivorship of BKA at 5 years and 58% at 17 years.

CONCLUSION

Current evidence suggests that modular BKA provides comparable functional outcome to TKA at short-term to midterm follow-up, however, with poor long-term survivorship.

Similar postoperative patient-reported outcome in both second generation patellofemoral arthroplasty and total knee arthroplasty for treatment of isolated patellofemoral osteoarthritis: a systematic review

INTRODUCTION

Due to inconsistent results and high failure rates, total knee arthroplasty (TKA) is more often used to treat isolated patellofemoral osteoarthritis (PFOA) despite the theoretical advantage of patellofemoral arthroplasty (PFA). It is perceived that second-generation PFA may have improved the outcomes of surgery. In this systematic review, the primary aim was to compare outcomes of second-generation PFA and TKA by assessment of patient-reported outcome measures (PROMs).

METHODS

A systematic search was made in PubMed, Medline, Embase, Cinahl, Web of Science, Cochrane Library and MeSH to identify studies using second-generation PFA implants or TKA for treatment of PFOA. Only studies using The American Knee Society (AKSS), The Oxford Knee Score (OKS) or The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) to report on PROMs were included.

RESULTS

The postoperative weighted mean AKSS knee scores were 88.6 in the second-generation PFA group and 91.8 in the TKA group. The postoperative weighted mean AKSS function score was 79.5 in the second-generation PFA group and 86.4 in the TKA group. There was no significant difference in the mean AKSS knee or function scores between the second-generation PFA group and the TKA group. The postoperative weighted mean OKS score was 36.7 and the postoperative weighted mean WOMAC score was 24.4. The revision rate was higher in the second-generation PFA group (113 revisions [8.4%]) than in the TKA group (3 revisions [1.3%]). Progression of OA was most commonly noted as the reason for revision of PFA, and it was noted in 60 cases [53.1%]; this was followed by pain in 33 cases [29.2%].

CONCLUSION

Excellent postoperative weighted mean AKSS knee scores were found in both the second-generation PFA group and in the TKA group, suggesting that both surgical options can result in a satisfying patient-reported outcome. Higher revision rates in the second-generation PFA studies may in part be due to challenges related to patient selection. Based on evaluation of PROMs, the use of second-generation PFA seems to be an equal option to TKA for treatment of isolated PFOA in appropriately selected patients. Hopefully, this can be considered by physicians in their daily clinical work.

LEVEL OF EVIDENCE

IV.

Return to the operating room after patellofemoral arthroplasty versus total knee arthroplasty for isolated patellofemoral arthritis-a systematic review

PURPOSE

Patellofemoral arthroplasty (PFA) and total knee arthroplasty (TKA) are accepted treatments for end-stage isolated patellofemoral osteoarthritis (PFOA). However, complications and re-operations have historically differed between the two procedures. We performed a systematic review to report on the re-operation rates between TKA and modern PFA for isolated PFOA.

METHODS

Systematically identified publications reporting on patients that underwent either TKA or modern PFA for isolated PFOA were reviewed. Meta-analysis software was used to screen potential articles with at least one year follow-up that detailed reasons for re-operation. Data was extracted and analyzed for all re-operations. Survival of the implant was used as the primary outcome; return to the operating room (OR) for any reason was used as a secondary outcome.

RESULTS

The weighted rate of either conversion or revision arthroplasty in the PFA group and the TKA group was 6.34 and 0.11, respectively. The weighted rate of return to the OR for bony and soft tissue procedures was 1.06 and 0.79, respectively. The weighted rate of manipulation under anaesthesia (MUA) was 0.32 and 1.23, respectively.

CONCLUSION

Patients who undergo PFA may be more likely to return to the operating room for conversion to TKA and/or revision surgery than those who undergo TKA.

Bicompartmental (uni plus patellofemoral) versus total knee arthroplasty: a match-paired study

BACKGROUND

Osteoarthritis (OA) of the knee, whether primary or post-traumatic, does not always involve all three compartments (tibiofemoral medial and lateral and the patellofemoral ones). Bicompartmental knee arthroplasty (BKA) was proposed as a good alternative to total knee arthroplasty when two of the three knee compartments were affected.

MATERIALS AND METHODS

We performed a retrospective comparative study collecting all BKAs performed between March 2010 and January 2016. During this period, we treated 27 patients with BKA for medial or lateral and patellofemoral OA. Seven of them were lost to follow-up and were not included in the study. Group A (BKA group) was compared to a homogeneous group of 20 patients who underwent TKA during the same period (group B).

RESULTS

Patients treated with TKA were younger than those treated with BKA (mean age 65 vs. 67.2; p = 0.2149). BKA resulted in longer mean operating time (87 vs. 82.4 min; p = 0.2983), less blood loss (413 vs. 458 ml; p = 0.0052) but higher blood transfusion rate (12 vs. 10%). Medium follow-up was 34 months for BKA group and 38 months for TKA group. No statistically significant differences were found in KSS score between the two groups (KSS score 92.3 for BKA, 94.5 for TKA; p = 0.5221; KSS function was 87.2 for BKA and 89.2 for TKA; p = 0.4985).

CONCLUSION

The most important finding of the present study was that although BKA seemed to be theoretically more favorable in terms of functional recovery and blood loss, patients of group A had lower KSS score and higher transfusion rate than those of group B. Our data confirm that BKA could be proposed as an alternative to TKA, especially in young and high-demanding patients.