Secondary Patellar Resurfacing Research Articles

Reasons for failure in primary total knee arthroplasty - An analysis of prospectively collected registry data

ObjectiveThe aim of this study was to determine the causes leading to a first revision of primary total knee arthroplasty (TKA) in a specialized knee centre and compare the results with previously published data. MethodsProspectively collected data of a consecutive number of 195 patients after primary TKA and who underwent first revision surgery after completing the diagnostic algorithm for persistent knee pain were included. Data was prospectively collected from a specialized knee centre in which the patients presented between 2015 and 2020 and retrospectively analysed. Indications for revision surgery were categorized using all available information from patients’ records. Patients were divided into early (up to two years) and late revision (more than two years). ResultsOverall mean time from index to revision surgery was 3.6 years. 49% of knee revisions occurred in the first two years, 51% after two years. 86% of the patients were referred to the knee centre from other surgeons. The most frequent reason for revision was instability, followed by patellofemoral problems, extensor mechanism insufficiency and malalignment. The most frequently performed revision was complete removal and re-implantation of a semi constrained implant design (52.5%) followed by revision using a full constrained implant design (16%). Secondary patella-resurfacing as part of complete revision was carried out in 71.5% of the cases. The majority of the patients showed concurrent reasons for TKA failure with significant correlations amongst another. Furthermore, correlations were identified between indications for revision surgery and revision implant designs. ConclusionIn a specialized knee centre the most common indications for the first TKA revision were instability and patellofemoral and/or extensor mechanism insufficiency followed by malalignment. In most patients there was not only one failure mode, but a combination of many. It is important to establish a standardized diagnostic algorithm to facilitate comprehensive and efficient diagnostics and the optimal treatment.

Is obesity associated with short-term revision after total knee arthroplasty? An analysis of 121,819 primary procedures from the Dutch Arthroplasty Register

BackgroundThe prevalence of obesity is increasing. The association with knee osteoarthritis is well documented, resulting in the population requesting total knee arthroplasty (TKA) for invalidating symptoms to be heavier in nature. The purpose of the current analysis was to assess the association between preoperative body mass index (BMI) and short-term revision rate after TKA. The secondary aim was to investigate the influence of implant fixation method on the association between BMI and survivorship. MethodsThis is a retrospective analysis of prospectively collected registry data (Dutch Arthroplasty Register; LROI). All primary TKA procedures in patients >18 years of age with registered BMI were selected (n = 121,819). Non-obese patients (BMI 18–25) were compared with overweight (BMI 25–30) and class I–III obese (BMI >30, >35, >40) patients. Crude all-cause revision rates were calculated using competing risk analysis. Adjusted hazard ratios (HRs) were determined with Cox multivariable regression analyses for all-cause, septic and aseptic revision and secondary patellar resurfacing. ResultsRevision rates were 3.3% for non-obese patients, 3.5% for overweight patients, 3.7% for class I obese patients, 3.6% for class II obese patients and 3.7% for class III obese patients. Class III obese patients had a significant higher risk for septic revision compared with non-obese patients (HR 1.53, 95% confidence interval (CI) 1.06–2.22). Class I obese patients had a higher risk for secondary patellar resurfacing (HR 1.52, 95% CI 1.12–2.08). All-cause and aseptic revision rates were similar between BMI groups. ConclusionsObesity appeared to be associated with some short-term revision risks after TKA, but was not associated with an overall increase in revision rate.

Age and Prosthetic Design as Risk Factors for Secondary Patella Resurfacing

BackgroundSelectively resurfacing the patella based on a patient’s risk of secondary patella resurfacing (SPR) may be the optimal strategy for primary total knee arthroplasty (TKA). However, exactly which factors increase the risk of SPR is unknown. Utilizing New Zealand Joint Registry data, we investigated the following: (1) What patient and surgical factors are more prevalent among TKA patients who received SPR compared to those who did not? and (2) What is the difference in Oxford Knee Scores (OKS) between those who receive SPR and those who do not? MethodsPrevalence of various patient and surgical factors was compared between 197 non-resurfaced TKAs that proceeded to SPR and 31,399 that did not. Multivariate analysis was used to determine the odds ratio for each factor that differed between groups. Six-month postoperative OKS for each group was utilized for comparison. ResultsPosterior-stabilized designs had an odds ratio of 1.86 (95% confidence interval [CI] 1.31-2.66; P = .001) when compared to cruciate-retaining designs. When compared to age less than 55, age >75 and age 65-74 had odds ratios of 0.27 (95% CI 0.16-0.46; P < .001) and 0.44 (95% CI 0.28-0.69; P < .001) respectively. Six-month OKS was lower among those who received SPR (37.27 vs 27.26; P < .001). ConclusionYounger age, posterior-stabilized design, and a low 6-month OKS were associated with SPR.

Bone SPECT/CT has excellent sensitivity and specificity for diagnosis of loosening and patellofemoral problems after total knee arthroplasty.

The primary purpose of this retrospective study with prospectively collected data was to evaluate the clinical value of SPECT/CT, in particular its impact on clinical diagnosis and patient management, in patients with pain, stiffness, or swelling after primary total knee arthroplasty (TKA). The secondary purpose was to determine the sensitivity and the specificity of SPECT/CT for different pathologies such as loosening and patellofemoral overloading. A retrospective analysis was carried out on 214 knees in 202 consecutive patients (mean age 69 ± 11years) with persistent or recurrent knee pain after TKA. All patients underwent clinical examination, standardised radiographs, and 99mTc-hydroxymethane diphosphonate (HDP) SPECT/CT as part of a routine diagnostic algorithm. The diagnoses before and after SPECT/CT and final treatment were recorded. TKA component position was routinely measured on 3D-reconstructed images. Intensity and anatomical distribution of bone tracer uptake were determined. SPECT/CT changed the clinical diagnosis and final treatment in 139/214 (65%) knees. In 117 (54.7%) out of 214 patients, revision surgery was proposed following SPECT/CT. Early onset of pain was significantly (p = 0.011) correlated with tibiofemoral stress pattern in SPECT/CT. A total of 86 knees (40.2%) were surgically revised using semi-constrained or fully constrained TKA. In 35 patients, a secondary patellar resurfacing was performed. SPECT/CT showed the clinical diagnosis to be incorrect for suspicion of tibial component loosening in 56 patients (26.2%), femoral component loosening in 53 patients (24.8%), and patellofemoral overloading/progressive patellofemoral osteoarthritis in 26 patients (12.1%) and provided different underlying causes of persistent knee pain after TKA. Likewise, SPECT/CT identified tibial component loosening in 8 patients (3.7%), femoral component loosening in 4 patients (1.9%), and patellofemoral OA in 71 patients (33.2%) without prior clinical suspected diagnosis. The sensitivity and specificity of SPECT/CT for detection of patellofemoral OA was 96.5% and 96.2%, respectively. The sensitivity and specificity for detection of tibial component loosening was 96.0% and 100%, respectively. The sensitivity and specificity for detection of femoral component loosening was 95.0% and 100%, respectively. The diagnostic benefits of SPECT/CT in the challenging and complex cohort of patients with pain after primary TKA have been proven. The excellent sensitivity and specificity for detection of tibial or femoral component loosening and diagnosis of patellofemoral OA have been surgically confirmed. Due to the benefits in establishing the correct diagnosis, SPECT/CT should be implemented as part of the routine diagnostic algorithm for patients with pain after primary TKA. II.

A 13- to 16-year clinical and radiological outcome study of the genesis II cruciate retaining total knee arthroplasty with an oxidised zirconium femoral component

PurposeThe Genesis II Total Knee Arthroplasty with an oxidized zirconium (OxiniumTM) femoral component (Smith & Nephew, Memphis, TN, USA) was introduced in an attempt to reduce polyethylene wear and osteolysis. MethodsWe retrospectively evaluated prospectively collected data from 245 consecutive patients (40 men and 205 women; mean age at surgery 70.1 years, range 44 to 85 years) who underwent 261 TKAs with a mean follow-up of 15.1 years (range 13 to 16 years). Implant failure rate, complication rate, clinical (both subjective and objective) and radiological outcomes were assessed. ResultsAt final follow-up, 24 (9.8 %) patients (24 TKAs) were lost to follow-up and 35 (14.3%) patients (35 TKAs) had died for reasons unrelated to surgery. Four TKAs, in four patients, were revised because of aseptic loosening. In five TKAs (five patients) secondary patella resurfacing was performed because of patellofemoral pain. Survivorship analysis showed a cumulative success rate of 98.4% (95% CI, 94.3% - 100%) at 15 years with revision for aseptic loosening as an end point, and 95.6% (95% CI, 92.7% - 98.7%) at 15 years with revision for any reason as an end point. All patients showed a statistically significant improvement (p = 0.01) in the Knee Society clinical rating system, WOMAC Score, KOOS Score, Oxford Knee Score and EuroQol 5D Score. Surgery fulfilled patient expectations for 90.1% of patients; in 5.4% it did not, and 4.5% declined to answer. ConclusionThis study demonstrates satisfactory long-term clinical results for this knee design.

Predictors for secondary patellar resurfacing after primary total knee arthroplasty using a "patella-friendly" total knee arthroplasty system.

Patellar resurfacing (PR) in total knee arthroplasty (TKA) is still one of the major controversies in orthopaedic surgery today. The aim of the present retrospective case-control study was to identify predictors for secondary patellar resurfacing (SPR) after initial TKA to create a rationale for surgeons to decide which patients to resurface primarily. It was hypothesized that proper TKA implantation and component positioning as well as a maintained physiological patellar geometry will lead to a reduced risk of SPR. Overmore, it was hypothesized that intrinsic factors like overweight might also have an influence on the need for SPR. After identification of suitable patients and age/sex matching in a 1:2 fashion, 29 cases (TKA/SPR) and 58 controls (TKA) were included and screened for available clinical and epidemiological data as well as for radiographic data after primary TKA. Pearson's correlation analysis as well as logistic regression modeling was performed to identify possible predictors for SPR following TKA. Binary logistic regression was able to correctly classify 88.5% of patients into case or control groups. It indicated that patella tilt, patella height, and thickness as well as the delta angle were significant predictors of a need for SPR following primary TKA. An increase in patellar width by 1mm will increase the risk of SPR, while an increase in patellar thickness by 1mm will reduce it. An increase in patellar tilt by 1° will also increase the risk of SPR. Finally, an increase in delta angle by 1° will again reduce the risk of SPR. Easy and accessible radiographic measurements have been identified as possible predictors of SPR following primary TKA. Although indication for primary PR may still remain a controversial topic, a rationale has been proposed in this study to support surgeons in objectively estimating an individual patient's risk for SPR prior to primary TKA measuring the patella tilt, width, and thickness. Overmore, regarding surgical aspects of TKA, tibial component positioning has also been shown to be of importance to reduce the risk of SPR.

A prospective evaluation of a largely cementless total knee arthroplasty cohort without patellar resurfacing: 10-year outcomes and survivorship

BackgroundThe theoretical benefits of a mobile bearing design in Total Knee Arthroplasty (TKA) include increased articular surface conformity with a reduction in both polyethylene wear and implant interface shear. However, to date these theoretical advantages have not been translated into published evidence of superior survivorship. This paper presents the results of a prospective, non-comparative study evaluating the performance of the mobile bearing Low Contact Stress LCS Complete Rotating Platform TKA in a largely cementless cohort without patellar resurfacing.Methods237 consecutive patients (240 knees) undergoing primary TKA were prospectively recruited. All received the LCS Complete Rotating Platform TKA (DePuy International, Leeds, UK). Clinical and radiographic assessments were performed at 3, 12, 60 and 120 months post-operatively. Radiographic evaluation was performed by an independent external surgeon.ResultsThe mean age was 70.3 years. 77.5% of cases were cementless. Radiographic assessment suggested excellent femoral component fixation. 22 tibial radiolucent lines (RLLs) > 1 mm were observed in 12 knees. No RLLs were progressive. There have been two revisions; one for late infection and one for aseptic loosening. No patients underwent secondary patellar resurfacing. The cumulative implant survivorship, using component revision for any reason as the endpoint, was 98.9% (95% CI, 95.6 to 99.7%) at 10 years.ConclusionsThe excellent survivorship at a minimum 10-year follow-up supports the use of uncemented porous coated fixation without patellar resurfacing with the non-posterior stabilized LCS Complete Rotating Platform TKA.

The outcome of secondary resurfacing of the patella following total knee arthroplasty: Results from the Trent and Wales Arthroplasty Register

BackgroundWe sought to determine whether patients undergoing secondary patella resurfacing (SPR) benefited from the procedure by assessing postoperative satisfaction via a postal questionnaire. MethodsAll such patients included in the Trent and Wales Arthroplasty Register were invited to participate using patient-reported outcome measures (PROMs). We identified 223 patients who had undergone SPR over a 20-year period. Forty-two had died according to death register checks. Eighty-eight of 181 (48.6%) questionnaires were completed. The mean age at resurfacing was 67 (min. 42, max. 81); 52% were female. The median time to follow-up was 55months (interquartile range (IQR) 41–111). Median time to SPR was 28months (IQR 20–42). ResultsThirty-nine patients (44%) felt that SPR resolved the problem of pain in the front of their knee. All PROMs were significantly better for those who felt that the resurfacing had worked (Oxford Knee Score 29 vs. 16, P<0.05, modified Kujala 51 vs. 32, P<0.05, EQ5D-3L 0.616 vs. 0.384, P<0.05). Based on PROMs, SPR produces a satisfactory outcome in two of every five patients. ConclusionsSurgeons must be clear on the cause of anterior knee pain post-total knee replacement, and patients must be made aware of what outcomes can be reasonably expected from this procedure.

Native Patella Retention Versus Resurfacing in a Cohort of Staged Bilateral Total Knee Patients

Background: Patellar resurfacing in total knee arthroplasty remains a point of controversy within the literature and the generally followed paradigm varies among regions.Methods: In effort to elucidate a difference following the change from universal patellar resurfacing to universal non-resurfacing, 32 patients with bilateral TKA that included one resurfaced and one native patella were retrospectively reviewed at average follow up 21.4 months from the most recent surgery.Results: No difference was observed in patient satisfaction, KOOS-ADL score, and VAS scores. No complications or secondary patellar resurfacing occurred.Conclusions: Therefore, patients perceive no difference between knees with native patella retention or a resurfaced patella in regards to pain and function.

The predictive factors of secondary patellar resurfacing in computer-assisted total knee arthroplasty. A prospective cohort study.

The decision to resurface the patella during total knee arthroplasty (TKA) remains controversial. This prospective cohort study aimed to evaluate the outcome and survivorship of the native patella in computer-assisted TKA (CAS TKA) implanted for primary knee osteoarthritis, and to determine the predictive factors of secondary patellar resurfacing (SPR). A prospective cohort of 273 cementless ultra-congruent mobile-bearing CAS TKA implanted without patellar resurfacing was included in our total joint registry. Patients were evaluated with the International Knee Society (IKS) and Hospital for Special Surgery Patellar (HSSP) scores. Radiographic evaluation was focused on the patellofemoral (PF) compartment to assess: the patellar dysplasia (Wiberg classification), PF osteoarthritis (Iwano classification), femoral trochlear dysplasia (femoral sulcus angle), patellar maltracking (patellar tilt and lateralization), and patella height (Blackburne-Peel ratio). At a six-year median follow-up, the CAS TKA survivorship using SPR as end-point was 95% (range, 91-99%). The IKS and HSSP improved significantly after SPR (p=0.001 and 0.004, respectively). No significant difference in the IKS and HSSP was detected between TKA with native patella and SPR-TKA at latest follow-up. Importantly, four pre-operative radiographic PF parameters were significantly associated with SPR: higher stages of patellar dysplasia and PF osteoarthritis, and higher sulcus angle and patellar lateralization (hazard ratios=5.1 to 11.6, p=0.009 to 0.04). When preserving the native patella, surgeons should be aware of pre-operative PF radiographic parameters that could influence the outcome and survivorship of CAS TKA leading to SPR. Particularly, evidence of PF dysplasia, osteoarthritis and maltracking should be determined pre-operatively to resurface the patella at the time of TKA. Therapeutic Level II (prospective cohort study).

Total Knee Arthroplasty in the 21st century: Why Do They Fail? A Fifteen-Year Analysis of 11, 135 Knees

Introduction and Aims:As national total knee arthroplasty (TKA) registries evolve, there is an increasing trend towards publication of hospital and surgeon-level outcome data, with the goal of stimulating efforts to optimise the results of TKA. Such efforts first require understanding of the current mechanisms of TKA failure. Previous reports on revision TKA from tertiary referral centres lack data on the overall denominator, thus the relative importance of each failure mechanism leading to TKA revision over long term follow up remains unclear. The aim of this study was to analyse reasons for revision following primary TKA, and assess their relative frequencies over long-term follow-up. Methodology:11,134 primary TKA performed between 2000-2015 at one of three tertiary referral hospitals were identified. ‘Failure’ was defined as patients undergoing subsequent revision surgery involving change of of one or more components or reoperation for deep periprosthetic joint infection (PJI). Patients were identified from a combination of the New Zealand National Joint Registry and individual search of patient records and clinical coding (ICD-9 and ICD-10). All relevant clinical records, radiographs, and lab results were obtained from all New Zealand hospitals to identify the primary reason for revision according to a standardised protocol. Results:A total of 357 (3.2%) failures over the 15 year period were identified. Of these, 36% were revised within one year and 56% were revised within 2 years of primary TKA. Periprosthetic joint infection (PJI) encompassed 48% of all reasons for revision, followed by aseptic loosening (15%), secondary patella resurfacing (14%), tibio-femoral instability (9%), stiffness (5%), polyethylene wear (2.5%), periprosthetic fracture (2.3%), patella maltracking (1.9%) and extensor mechanism discontinuity (0.9%). In the first 5 years following primary TKA, the most common reason for revision was PJI (52%), from 5-10 years PJI and aseptic loosening (35% each), and from 10-15 years aseptic loosening (41%). Conclusion:In this large cohort of patients with comprehensive follow up, PJI was the dominant reason for failure particularly in the first 10 years. Aseptic loosening becomes more important after 10 years follow up. Efforts to improve outcomes following primary TKA should focus on these areas, particularly prevention of PJI.

The need for secondary resurfacing is affected by trochlear height in total knee arthroplasty.

The purpose of the study was to compare the rate of secondary resurfacing in a consecutive series of five different total knee arthroplasty (TKA) systems. It was our hypothesis that different TKA design features such as sulcus angle or trochlear height influence the rate of secondary resurfacing. A retrospective study was performed on data from patients who underwent TKA without primary patellar resurfacing from 2004 to 2012 in an university-affiliated hospital. The study cohort included 784 TKA patients (m:f=302:482, mean age at surgery±SD 71±10). Five different cruciate-retaining TKA systems were used consecutively (Group A, Triathlon, Stryker, Switzerland (n=296), Group B, PFC Sigma, DepuySynthes, Switzerland (n=215), Group C, LCS, DepuySynthes, Switzerland (n=81), Group D, Balansys, Mathys, Switzerland (n=128), Group E, Duracon, Stryker, Switzerland (n=64)). Data were retrospectively obtained from hospital archives. Patients demographics, age at surgery, type of TKA were noted. In addition, TKA component position was assessed on radiographs with respect to "The knee society total knee arthroplasty roentgenographic evaluation and scoring system" (TKA-RESS). Pearson Chi-square test was used to compare differences between groups (p<0.05). There were no significant differences between the groups in terms of age, gender, and radiological outcomes. Twenty-six of 784 patients (3.3%) underwent secondary resurfacing due to patellofemoral pain. In group A 4/296 patients (1.4%), in group B 15/215 patients (7%), in group C 5/81 patients (6.2%), in group D 1/128 patients (0.8%), in group E 1/64 patients (1.6%) underwent secondary patellar resurfacing during follow-up. Significantly higher rates of secondary patellar resurfacing were seen in groups B and C when compared to the others (p<0.001). It was found that the trochlear height in these TKA was higher than in the others. Based on the findings of this study, trochlear height influences the need for secondary patellar resurfacing. The resurfacing rate ranged from 1 to 7%, with the highest rate in the PFC Sigma TKA. Therapeutic study, Level III.

Revision Total Knee Arthroplasty for Instability—Outcome for Different Types of Instability and Implants

BackgroundGiven the mixed outcome after revision total knee arthroplasty (TKA) for instability in the literature and the relative high recurrence of instability, we were interested in the outcome of a cohort of patients operated for various types of clinical instability and with different types of implants. MethodsA total of 77 patients with unstable TKA were completely revised (19 hinged and 58 condylar implants). We classified the patients in 3 instability groups based on the literature: (1) anterior-posterior flexion instability (N = 29); (2) medial-lateral flexion instability (N = 16); and (3) multiplane instability (N = 32). Patients were evaluated up to 24 months postoperatively, concerning Knee Society clinical rating system, range of motion, visual analog scale (VAS) pain, and VAS satisfaction. ResultsFor the total group, all outcome scores improved, but substantial residual pain (VAS = 41) was reported. For type of instability, the clinical outcome was similar for all the groups. For type of implant, the hinged group had lower postoperative outcome scores but similar satisfaction scores compared with those in the condylar group. There was a considerable number of insert changes and secondary patellar resurfacing in the condylar group compared with no reoperations in the hinged group. Recurrent instability was not seen in the anterior-posterior flexion instability group and in patients who received a condylar constraint-type implant. ConclusionsWe recommend 3 options in revision TKA for instability: (1) hinged implants in cases with severe ligament instability in multiple planes or bone loss, (2) condylar implants with a posterior-stabilized insert in cases with isolated posterior cruciate ligament insufficiency, and (3) condylar implants with condylar constraints in all other cases.

Patient Satisfaction and Functional Outcomes Following Secondary Patellar Resurfacing.

When secondary patellar resurfacing is performed, a uniformly and widely used scoring system that is validated for anterior knee pain caused by a retropatellar degeneration will give more insight into the results of this procedure. The cause of anterior knee pain following total knee arthroplasty (TKA) is not always related to the patella itself. Other causes have been identified, such as an insufficient posterior cruciate ligament in the case of a posterior cruciate-retaining TKA or an internally rotated femoral and/or tibial component. Treatment of anterior knee pain following primary TKA with secondary patellar resurfacing is a controversial procedure with uncertain outcomes. The purpose of this study is to systematically review the available peer-reviewed literature on patient satisfaction and functional outcomes of secondary resurfacing. The authors performed a systematic computerized database search of the Cochrane Database of Systematic Reviews, MEDLINE, and EMBASE in October 2014. The quality of the included studies was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. A total of 15 articles met the inclusion criteria. In total, 148 (64%) of 232 patients were satisfied with the outcomes of secondary patellar resurfacing. A statistically significant improvement in knee scores was noted in all 9 studies that reported functional outcomes, although no clinically significant improvement in knee scores was observed. Reported complications include infections and impaired wound healing, patellar instability, and patellar fracture. Because the available evidence is of generally low quality, the results of this systematic review only support a weak recommendation for secondary patellar resurfacing if patient satisfaction and clinically important improvement of functional outcomes are the desired endpoints. [Orthopedics.2016; 39(5):e850-e856.].

Retrospective 5-Year Analysis of Revision Rate and Functional Outcome of TKA With and Without Patella Implant.

The aim of this study was to compare a patient cohort after total knee arthroplasty (TKA) in terms of the revision rate and the functional outcome, with and without patella resurfacing. Sixty-six patients (71 TKAs) were implanted with the mobile-bearing knee prosthesis system e.motion UC (Aesculap AG, Tuttlingen, Germany). These patients were divided into 2 groups, 1 of which received primary patella resurfacing (PPR; 51 TKAs) and 1 of which did not (non-PPR; 20 TKAs), with an average follow-up of 65.6 months (±6.9). The cohort was recorded consecutively. The evaluation was performed using the Knee Society Score and selected questions relating to the Knee Injury and Osteoarthritis Outcome Score, as well as with radiographs. Results showed that PPR was no better than non-PPR in terms of functional outcome. Two knees (10%) were revised in the non-PPR group, and 1 knee (1.96%) in the PPR group (not significant). In this cohort, 100% of implants, including the 5 TKAs of patients who did not attend the follow-up examination, had neither explanted nor loosened at the time of follow-up examination. The authors concluded that the revision rate for PPR is slightly lower, and this avoids the need for secondary patella resurfacing. The risk for complications is low, and the functional outcome is comparable. [Orthopedics. 2016; 39(3):S31-S35.].

Secondary Patellar Resurfacing as a Rescue Procedure for Persistent Anterior Knee Pain After Primary Total Knee Arthroplasty: Do Our Patients Really Improve?

BackgroundSecondary patellar resurfacing (SPR) is a procedure that can be used in patients with persistent anterior knee pain (AKP) after a primary total knee arthroplasty. The aim of our study was to analyze the clinical and functional outcomes as well as the complications of this procedure and identify predictive factors for a favorable outcome. MethodsForty-six patients who underwent SPR for persistent AKP after primary total knee arthroplasty were retrospectively studied. The patient’s mean age was 68 years (range, 36-86 years). The average follow-up time after SPR was 74 months (range, 24-197 months). Demographic data, Knee Society Score scale, range of motion, pain improvement (Visual Analogue Scale), overall satisfaction, and complications were recorded. The statistical analysis was performed using STATA tm/SE v10. ResultsThere was an improvement of the Knee Society scale (from 54 ± 11 to 64 ± 16 points; P < .05). However, in 59% of the cases, there was no pain improvement, and 65% of patients were not satisfied. Four patients showed complications, and in 2 cases, reoperation was necessary. We did not find any preoperative predictive factor for a favorable outcome after SPR. ConclusionDespite improvement of the Knee Society scale, many patients continue with AKP and are dissatisfied with this procedure; therefore, we do not recommend it in this clinical scenario.

Study to Determine Prevalence of Patellofemoral Symptoms after Total Knee Arthroplasty with Non-Resurfacing of the Patella

Background: The controversy over whether or not to routinely resurface the patella during a total knee arthroplasty has persisted despite three decades of successful joint arthroplasty procedures. Advocates for routine patellar resurfacing admit the occasional need for secondary patellar resurfacing and declare increased prevalence of anterior knee pain in patients with non-resurfaced patellae as a cause for worry. Surgeons that leave the patella non-resurfaced cite avoidance of complications that include patellar fracture, avascular necrosis, patellar tendon injury and instability. Objective: To study the prevalence of post-op patellofemoral symptoms like anterior knee pain, clunk and crepitus in patients underwent total knee arthroplasty with non-resurfacing of the patella. Methods: Retrospective study was conducted among the patients who had total knee arthroplasty without resurfacing. Patients were examined by a specialist to check for any patellofemoral symptoms like anterior knee pain, clunk and crepitus. The knee pain questionnaire was used. Statistical analysis: Descriptive statistics like mean, standard deviation and proportion and percentages. Results: Total 156 study subjects participated in the study. Mean follow-up was 47.7 months (SD=4.5 months). The prevalence of anterior knee pain was 4.2%. Prevalence of patellar crepitus was 7.1%. No other complications were recorded in the study participants. Conclusion: Prevalence of post-op PF pain, clunk and crepitus is low among who had total knee arthroplasty without resurfacing.

Secondary patella resurfacing in painful non-resurfaced total knee arthroplasties : A study of survival and clinical outcome from the Norwegian Arthroplasty Register (1994-2011).

In Norway, 19 % of revisions of non-resurfaced total knee arthroplasties done for knee pain between 1994 and 2011 were Secondary Patella Resurfacing (SPR). It is, however, unclear whether SPR actually resolves the pain. The aim was to investigate prostheses survival and clinical outcomes following SPR. A total of 308 knees (301 patients) with SPR were used to assess implant survival, and a sub-cohort (n = 114 out of 301 patients) with Patient Reported Outcome Measures (PROMs) data were used to assess the clinical outcomes. The EuroQol (EQ-5D), the Knee Injury and Osteoarthritis Outcome Score, and Visual Analogue Scales on satisfaction and pain were used to collect PROM data. Outcomes were analysed by Kaplan-Meier, Cox regression, and multiple linear regression. The five- and ten-year Kaplan-Meier survival percentages were 91 % and 87 %, respectively. Overall, 35 knees were re-revised at a median follow-up of eight years and pain alone (10 knees) was the main cause of re-revision. Younger patients (<60 years) had nearly nine times higher risk of re-revision compared to older patients (>70 years) (RR = 8.6; p < 0.001). Mean EQ-5D index score had improved from 0.41 (SD 0.21) preoperative to 0.56 (SD 0.25) postoperative following SPR. A total of 63 % of patients with PROM data were satisfied with the outcomes of SPR. The long-term prostheses survival following SPR was satisfactory, although not as good as for primary knee replacement. Patients' health related quality of life improved significantly following SPR. Still, more than a third of patients with PROMs data were dissatisfied with the outcomes of the SPR procedure.

Secondary patellar resurfacing following total knee arthroplasty : A cohort study in fifty eight knees with a mean follow-up of thirty one months.

If anterior knee pain (AKP) emerges or persists following total knee arthroplasty (TKA), secondary patellar resurfacing (SPR) may offer relief of AKP. The purpose of our study was to evaluate the mid-term clinical outcomes after secondary patellar resurfacing for persistent AKP. Secondary objectives were to correlate surgical outcomes with clinical and radiological parameters including 99 m-technetium bone scintigraphy. In this study, 57 patients (58 knees, 51 women and 6 men) with a mean age of 70 years at the time of SPR were included. Patients were asked about their satisfaction regarding the outcome of the procedure. Patellar position was assessed by axial radiographs, and we reassessed the preoperatively performed bone scintigraphy. After a median follow-up of 31 (6-76) months, 42 patients (43 knees) were satisfied and 15 were dissatisfied regarding the outcome of the procedure. Dissatisfied patients had more often a shorter time interval between TKA and SPR, patellar tilt on axial radiographs, and a 'hot' bone scan. In patients with persistent AKP following TKR, secondary resurfacing leads to patient satisfaction in a relatively large number of patients. Better results were seen in patients without tilting of the patella. The added value of a bone scan as an indicator to perform SPR is not clarified in the present study.

Obliteration of Intercondylar Notch Mimicking Flexion-Extension Gap Imbalance in a Cruciate Retaining Total Knee Arthroplasty.

Following total knee arthroplasty (TKA), the most frequent cause of extension deficit and limitation of range of motion in early postoperative period is related to improper tensioning of soft tissues and failure to balance extension and flexion gaps. If a cruciate retaining (CR) prosthesis is the planned implant, then attention should be given to balancing the posterior cruciate ligament (PCL), and any factor that alters this balance may also cause deterioration of knee balance in postoperative period. Here, we report on an unusual case referred from another hospital because of continuous pain and restriction of knee motion in early postoperative period following CR-designed TKA that was initially thought to be due to flexion-extension imbalance. However, during the revision procedure, extruded cement to the intercondylar notch was found to be both mechanically blocking terminal extension and limiting flexion by possible mechanism of irritation of the synovial nerve endings around the stretched anterior fibers of PCL during flexion. This case was successfully treated by removal of extruded cement from intercondylar notch to decompress PCL, polyethylene exchange, and secondary patellar resurfacing.