Incidence and reasons for nonrevision reoperation after total knee arthroplasty

Predictors of reoperation and survival experience for primary total knee arthroplasty in young patients with degenerative and inflammatory arthritis

INTRODUCTION

While total knee arthroplasty (TKA) is typically implemented in patients > 65 years old, young patients may need to undergo TKA for pain relief and functional improvement. Current data are limited by older cohorts and short-term survival rates. This study aimed to examine a large sample size of patients with degenerative and inflammatory conditions who underwent primary TKA at a young (≤ 40) age to identify predictors of reoperation, as well 15-year survivorship.

MATERIALS AND METHODS

A retrospective study was performed on 77 patients (92 surgeries) who underwent primary TKA at ≤ 40 years old, between January 1990 and January 2020. Patient charts were reviewed and a multivariable logistic regression model identified independent predictors of reoperation. Kaplan-Meier analysis was employed to build survival curves and log-rank tests analyzed survival between groups.

RESULTS

Of the 77 patients, the median age at the time of surgery was 35.7 years (IQR: 31.2-38.7) and median follow-up time was 6.88 years. Twenty-one (22.8%) primary TKAs underwent 24 reoperations, most commonly due to stiffness (n = 9, 32.1%) and infection (n = 13, 46.4%) more significantly in the OA group (p = 0.049). There were no independent predictors of reoperation in multivariable analysis, and 15-year revision-free survivorship after TKA did not differ by indication (77.3% for OA/PTOA vs. 96.7% for autoimmune, p = 0.09) or between ≤ 30 and 31-40 year age groups (94.7% vs. 83.6%, p = 0.55).

CONCLUSIONS

In this cohort of patients ≤ 40 years old, revision-free survival was comparable to that reported in the literature for older TKA patients with osteoarthritis/autoimmune conditions (81-94% at 15-years). Though nearly a quarter of TKAs required reoperation and causes of secondary surgery differed between degenerative and inflammatory arthritis patients, there were no significant predictors of increased reoperation rate. Very young patients ≤ 30 years old did not have an increased risk of revision compared to those aged 31-40 years.

Global mapping of institutional and hospital-based (Level II-IV) arthroplasty registries: a scoping review

PURPOSE

Four joint arthroplasty registries (JARs) levels exist based on the recorded data type. Level I JARs are national registries that record primary data. Hospital or institutional JARs (Level II-IV) document further data (patient-reported outcomes, demographic, radiographic). A worldwide list of Level II-IV JARs must be created to effectively assess and categorize these data.

METHODS

Our study is a systematic scoping review that followed the PRISMA guidelines and included 648 studies. Based on their publications, the study aimed to map the existing Level II-IV JARs worldwide. The secondary aim was to record their lifetime, publications' number and frequency and recognise differences with national JARs.

RESULTS

One hundred five Level II-IV JARs were identified. Forty-eight hospital-based, 45 institutional, and 12 regional JARs. Fifty JARs were found in America, 39 in Europe, nine in Asia, six in Oceania and one in Africa. They have published 485 cohorts, 91 case-series, 49 case-control, nine cross-sectional studies, eight registry protocols and six randomized trials. Most cohort studies were retrospective. Twenty-three per cent of papers studied patient-reported outcomes, 21.45% surgical complications, 13.73% postoperative clinical and 5.25% radiographic outcomes, and 11.88% were survival analyses. Forty-four JARs have published only one paper. Level I JARs primarily publish implant revision risk annual reports, while Level IV JARs collect comprehensive data to conduct retrospective cohort studies.

CONCLUSIONS

This is the first study mapping all Level II-IV JARs worldwide. Most JARs are found in Europe and America, reporting on retrospective cohorts, but only a few report on studies systematically.

The Cost of Stiffness After Total Knee Arthroplasty

BACKGROUND

Stiffness after primary total knee arthroplasty (TKA) is debilitating and poorly understood. A heterogenous approach to the treatment is often utilized, including both nonoperative and operative treatment modalities. The purpose of this study was to examine the prevalence of treatments used between stiff and non-stiff TKA groups and their financial impact.

METHODS

An observational cohort study was conducted using a large database. A total of 12,942 patients who underwent unilateral primary TKA from January 1, 2017, to December 31, 2017, were included. Stiffness after TKA was defined as manipulation under anesthesia and a diagnosis code of stiffness or ankylosis, and subsequent diagnosis and procedure codes were used to identify the prevalence and financial impact of multiple common treatment options.

RESULTS

The prevalence of stiffness after TKA was 6.1%. Stiff patients were more likely to undergo physical therapy, medication, bracing, alternative treatment, clinic visits, and reoperation. Revision surgery was the most common reoperation in the stiff TKA group (7.6%). The incidence of both arthroscopy and revision surgery were higher in the stiff TKA population. Dual component revisions were costlier for patients who had stiff TKAs ($65,771 versus $48,287; P < .05). On average, patients who had stiffness after TKA endured costs from 1.5 to 7.5 times higher than the cost of their non-stiff counterparts during the 2 years following index TKA.

CONCLUSION

Patients who have stiffness after primary TKA face significantly higher treatment costs for both operative and nonoperative treatments than patients who do not have stiffness.

Decrease of tibial tuberosity trochlear groove distance following mechanically aligned total knee arthroplasty

PURPOSE

Anterior knee pain (AKP) is common following total knee arthroplasty. The tibial tuberosity trochlear groove distance (TTTG) influences patellofemoral joint loading in the native knee. Increased TTTG may lead to maltracking of the patella and anterior knee pain. The purpose of this study was to investigate potential changes in TTTG following total knee arthroplasty (TKA).

METHODS

TTTG was measured on preoperative CT data on a consecutive series of patients scheduled to receive TKA with patient-specific instrumentation, and compared to a computer simulation of the postoperative TTTG. Preoperative TTTG was measured with a 3D planning software in 250 knees. The postoperative result was simulated and TTTG measured within the software. Three different groups were analysed: neutral (180° ± 3) (n = 50), valgus (> 190°) (n = 100), and varus (< 170°) (n = 100).

RESULTS

Median preoperative to simulated postoperative TTTG decreased from 15.0 [interquartile range (IQR) 6.0] mm to 6.5 (IQR 5.0) mm for all axes combined. A significant postoperative reduction of TTTG was found in each group (p < 0.001). The mean change in TTTG did not differ significantly between the groups [- 8.8 (IQR 5.5) mm neutral, - 8.3 (IQR 7.0) mm valgus, - 7.5 (IQR 5.8) mm varus, p = 0.223].

CONCLUSION

This computer-based study suggests that mechanically aligned TKA significantly decreases TTTG distance in neutral, valgus and varus knees, assuming that the postoperative result coincides with the preoperative planning. Further study is warranted to evaluate the clinical relevance of this finding.

The effect of age on the outcomes of cementless mobile bearing unicompartmental knee replacements

PURPOSE

Unicompartmental Knee Replacements (UKR) are being performed in patients with increasing demands and life expectancies with surgical concerns that cemented fixation will not last. Cementless fixation may offer a solution, but the results in different age groups have not been assessed. The effect of age at surgery on the outcomes of cementless UKRs was investigated.

METHODS

A prospective cohort of 1000 medial cementless mobile bearing UKR were analysed. Patients were categorised into four age groups (< 55, 55 to < 65, 65 to < 75 and ≥ 75 years). Implant survival was assessed using endpoints reoperation, revision and major revision requiring revision knee replacement components. Functional outcomes were assessed.

RESULTS

10 year cumulative revision rate for the < 55, 55 to < 65, 65 to < 75 and ≥ 75 groups were 2.1% (CI 0.6-6.1), 1.8% (CI 0.6-5.3), 3.2% (CI 1.5-6.5) and 4.1% (1.7-9.6) with no differences between groups (p = 0.52). Two of the 22 revisions were considered major. The 10 year cumulative reoperation rates were 4.5% (CI 2.0-10.0), 3.0% (CI 1.3-6.5), 3.8% (CI 2.0-7.1) and 4.1% (CI 1.7-9.6) with no differences between groups (p = 0.81). The 10 year median Oxford Knee Scores were 42.5, 46.5, 45 and 42.5, respectively. The 10 year median Objective American Knee Society Scores were 95 for all age groups.

CONCLUSION

The cementless mobile bearing UKR has low reoperation and revision rates and similar functional outcomes in all age groups. Cementless UKR should be used in all age groups and age should not be considered a contraindication.

LEVEL OF EVIDENCE

III.

Risk Factors for Patellar Clunk or Crepitation after Primary Total Knee Arthroplasty: A Systematic Review and Meta-analysis

Patellar clunk and crepitation (PCC) have been reported as a consequence of primary total knee arthroplasty (TKA). The incidence and contributing factors have not been fully defined. We performed this systematic review to evaluate factors associated with PCC following primary TKA. We identified studies on PCC following TKA from an electronic search of articles in Medline, Embase and the Cochrane databases (dated up to May 2018). Eighteen studies altogether, including 600 cases of PCC within 8,131 TKAs, were included in the meta-analysis. Several factors including demographic, intraoperative, clinical variables, and radiographic measurements were pooled for meta-analysis. Among intraoperative and clinical variables, patients involved with patellar retention (odds ratio [OR] = 9.420; confidence interval [CI]: 5.770-13.070), lateral reticular release (OR = 2.818; CI: 1.114-7.125), and previous surgery (OR = 2.724; CI: 1.549-4.790) were more likely to having PCCs. Among radiographic measurements, increased anterior tibial offset (weighted mean difference [WMD] = 0.387; CI: 0.139-0.634), increased joint line changes (WMD = 1.325; CI: 0.595-2.055), and increased knee flexion angle (WMD = 3.592; CI: 1.811-5.374) were considered risk factors associated with PCC. Demographic factors (age, gender, body mass index [BMI], and diagnosis) and other reported radiographic measurements were not associated with PCCs. This study identified intraoperative variables (patellar retention and lateral reticular release), clinical variables (previous surgery), and radiographic measurements (increased anterior tibial offset, increased joint line changes, and increased postoperative knee flexion angle) that contribute to an increased risk for PCC. Modifiable factors (patellar retention and lateral reticular release) should be considered and addressed to limit the risk for PCC following TKA. Patients with conditions that may not be modifiable may benefit from counseling about their increased risks for PCC to limit potential dissatisfaction with their procedure.

Total knee arthroplasty in dialysis patients: Is it safe? A systematic review of the literature

Purpose

This systematic review characterizes the safety and efficacy of total knee arthroplasty (TKA) in end stage renal disease (ESRD) patients due to the unique challenges they face.

Results

The cumulative complication rate for 3684 patients on dialysis for ESRD after primary TKA was 25%(N = 925/3702), with incidence rates of 2.5%(N = 92/3702) for periprosthetic joint infection, 3.7%(N = 71/1895) for reoperations, and 2.5%(N = 90/3578) for mortality.

Conclusion

Patients on dialysis for ESRD face significant mortality rates after primary TKA, in addition to other major complications. Careful counseling regarding risks and benefits should be provided prior to TKA in this population.

Anterior knee pain after total knee arthroplasty: A multifactorial analysis

PURPOSE

Dissatisfaction and an impaired quality of life after total knee arthroplasty (TKA) is often associated with postsurgical anterior knee pain (AKP). The underlying pathological mechanisms are not yet fully understood. Therefore, a multifactorial approach encompassing clinical and radiological parameters seemed reasonable and promising to investigate postsurgical AKP.

METHODS

In this cross-sectional study, 25 patients without and 25 patients with postsurgical AKP after unilateral TKA were randomly recruited from a larger cohort of patients. Multiple clinical and radiological parameters-including real-time shear wave elastography (SWE) to measure the patellar and quadriceps tendon elasticity-were acquired and subsequently associated with AKP. For statistical analysis, SPSS (IBM, version 25) was used.

RESULTS

In total 50 participants (58.0% men, mean age 63.42 years, mean body mass index 29.75 kg/m²), having different prosthetic designs implanted, were included. Independently of key covariates, the strength of the quadriceps muscle (p = 0.021), a thinner inlay (p = 0.041), and a lower position of the patella (p = 0.041) were associated with AKP. Although no correlation with AKP was found (p = 0.346, resp. p = 0.154), we observed significantly decreased Young's modulus of the patellar and quadriceps tendons for the involved knee compared to the uninvolved knee (p < 0.001).

CONCLUSION

In conclusion, quadriceps muscle strength, inlay thickness, and the patella position might be of particular relevance in avoiding postsurgical AKP. Future studies with larger sample sizes are needed to clarify the impact of quadriceps muscle strength and the postoperative patella position as well as the role of SWE as a personalized modifiable prediction marker.

Patients with Dupuytren's Contracture, Ledderhose Disease, and Peyronie's Disease are at higher risk of arthrofibrosis following total knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is a successful treatment for patients with late stage osteoarthritis, yet arthrofibrosis remains a consistent cause of TKA failure. Dupuytren's, Ledderhose and Peyronie's Diseases are related conditions of increased fibroblast proliferation. The aim of this study was to identify whether an association exists between these conditions and arthrofibrosis following TKA.

METHODS

Patient records were queried from 2010 to 2016 using an administrative claims database to compare the rates of arthrofibrosis, manipulation under anesthesia (MUA), lysis of adhesions (LOA), and revision TKA in patients with independent chart diagnoses of Dupuytren's Contracture, Ledderhose, or Peyronie's Diseases versus those without. Complications were queried and compared using multivariate logistic regression.

RESULTS

Patients with Dupuytren's (n = 5,232) and Ledderhose (n = 50,716) had a significantly higher rate of ankylosis following TKA: 30-days (OR, 1.54; OR, 1.23), 90-days (OR, 1.20; OR, 1.24), 6-months (OR, 1.23; OR, 1.23), and 1-year (OR, 1.28; OR, 1.23), while patients with Peyronie's (n = 1,186) had a higher rate of diagnosis at 6-months (OR, 1.37) and 1-year (OR, 1.35). Patients with diagnoses of any of the fibroproliferative diseases had a statistically higher risk of MUA at 90-days, 6-month, and 1-year following primary TKA. These cohorts did not have a significantly higher rate of revision TKA.

CONCLUSION

There is an increased odds risk of arthrofibrosis and MUA in patients who have undergone TKA and have a diagnosis of Dupuytren's Contracture, Ledderhose, or Peyronie's Diseases. Improvements to frequency and application of post-operative treatment should be considered in these cohorts to improve outcomes.

Management of Gonarthrosis with a Rotating Hinge Prosthesis: Minimum 10-Year Follow-up

BACKGROUND

The use of hinged designs is usually reserved for severe deformities or instability in contemporary total knee arthroplasty (TKA). Results have been mixed with some authors reporting relatively high incidences of complications. The aim of this study is to present the results of primary TKA performed with a hinged prosthesis with a minimum 10-year follow-up. We also examined the factors that influence survivorship of this prosthesis.

METHODS

A total of 238 primary TKA procedures were performed using hinged prostheses. Indications included osteoarthritis, rheumatoid arthritis, posttraumatic deformity, and arthritis. Clinical outcomes were assessed using the Hospital for Special Surgery score. Radiologic assessment was performed at each follow-up. Survivorship was calculated based on the Kaplan-Meier method. All complications were documented.

RESULTS

Mean follow-up was 13.5 years (standard deviation [SD], 3.4). Mean flexion at final review was 118° (SD, 20°). Fifty-four percent and 20% reported excellent and good functional scores, respectively. Survivorship was 94% at 13.5 years in patients over 60 years of age and 77% in patients less than 60 years of age. Survivorship in patients with preoperative varus deformity was 96% and that in valgus knees was 79%.

CONCLUSIONS

The results of this study suggest that when rotating hinges are used for primary TKA, the best results are achieved in patients over 60 years old. The indications for this design in the setting of primary TKA include significant deformities, severe bone loss, and ligamentous laxity.

Human Fibrosis: Is There Evidence for a Genetic Predisposition in Musculoskeletal Tissues?

BACKGROUND

Pathologic fibrosis is characterized by dysregulation of gene expression with excessive extracellular matrix production. The genetic basis for solid organ fibrosis is well described in the literature. However, there is a paucity of evidence for similar processes in the musculoskeletal (MSK) system. The purpose of this review is to provide an overview of existing evidence of genetic predisposition to pathologic fibrosis in the cardiac, pulmonary, and MSK systems, and to describe common genetic variants associated with these processes.

METHODS

A comprehensive search of several databases from 2000 to 2019 was conducted using relevant keywords in the English language. Genes reported as involved in idiopathic fibrotic processes in the heart, lung, hand, shoulder, and knee were recorded by 2 independent authors.

RESULTS

Among 2373 eligible studies, 52 studies investigated genetic predisposition in terms of variant analysis with the following organ system distribution: 36 pulmonary studies (69%), 15 hand studies (29%), and 1 knee study (2%). Twenty-two percent of gene variants identified were associated with both pulmonary and MSK fibrosis (ie, ADAM, HLA, CARD, EIF, TGF, WNT, and ZNF genes). Genetic variants known to be involved in the MSK tissue development or contractility properties in muscle were identified in the pulmonary fibrosis.

CONCLUSION

Despite shared genetic variations in both the lung and hand, there remains limited information about genetic variants associated with fibrosis in other MSK regions. This finding establishes the necessity of further studies to elucidate the genetic determinants involved in the knee, shoulder, and other joint fibrotic pathways.

LEVEL OF EVIDENCE

Level III.

Prior Manipulation under Anesthesia is a Predictor of Contralateral Manipulation in Staged Bilateral Total Knee Arthroplasty

BACKGROUND

There are many risk factors for arthrofibrosis and manipulation under anesthesia (MUA) following total knee arthroplasty (TKA). However, no study has elucidated whether a history of MUA increases the risk of contralateral MUA in patients undergoing staged bilateral TKA.

METHODS

A retrospective review of an institutional database of TKAs was performed. All patients aged ≥18 years who underwent primary staged bilateral TKAs were screened for inclusion. Staged bilateral TKAs were viewed as 2 distinct events based on the temporal order in which they occurred: TKA#1 (occurred first) and TKA#2 (occurred second). Following TKA#1, patients were split into 2 groups: those who underwent MUA (Group MANIP) and those who did not (Group NO MANIP). The subsequent risk of undergoing MUA following TKA#2 was then assessed and compared between the 2 groups. Chi-squared tests were used for comparison.

RESULTS

A total of 5,330 patients who underwent primary uncomplicated staged bilateral TKAs (10,660 knees) during the study period were identified. Overall, 2.1% of patients underwent MUA following TKA#1 and 1.9% of patients underwent MUA following TKA#2. In the MANIP group, 21.4% of patients underwent MUA following TKA#2, while only 1.5% underwent MUA in the NO MANIP group. This 14.3-fold increase in the risk of MUA in the MANIP group following TKA#2 was statistically significant (21.4% vs 1.5%, absolute risk reduction = 19.9%, relative risk reduction = 93.0%, P < .0001).

CONCLUSION

Patients who undergo MUA during the first TKA of a staged bilateral TKA are 14.3 times more likely to undergo a subsequent MUA than those who did not undergo MUA following their first TKA.

Factors Influencing Survivorship in Vasculopathic Patients

Total knee arthroplasty (TKA) in patients with peripheral vascular disease has sparsely been studied. This study examined patient and radiographic factors that could affect reoperation free survival in these patients. We retrospectively reviewed TKA procedures performed in patients with nonpalpable pulses on physical examination between January 1, 2004, and December 31, 2013. Ninety-two cases met inclusion criteria. Preoperative ankle-brachial index (ABI), date of surgery, sex, age, body mass index (BMI), tourniquet use, American Society of Anesthesiologists (ASA) score, presence of preoperative calcifications, and follow-up data were obtained. Failure was defined as reoperation. Patients were included if they experienced a failure or had at least 2 years of follow-up. Reoperation free survival was calculated by Kaplan-Meier's analysis. Odds ratios (ORs) were calculated for patient factors; hazard ratios (HRs) were calculated by Cox's regression analysis. Ninety-two TKAs were included in the study. Mean age was 68.8 years, mean BMI was 32.15, and mean ASA score was 2.44. Tourniquet was used in 78 patients. Mean preoperative ABI was 1.016. Nine patients had calcifications on X-ray prior to surgery. Reoperation free survival was 9.378 years. Patients with a preoperative ABI of below 0.7 had shorter reoperation free survival (ABI <0.7, 6.854 years; ABI >0.7, 9.535 years; p = 0.015). Patients with a preoperative ABI below 0.7 had greater odds of failure and were at higher risk for earlier failure (OR = 6.5, p = 0.027; HR = 1.678, p = 0.045). When corrected for age, sex, and BMI, the HR for patients with a preoperative ABI below 0.7 worsened (HR = 1.913, p = 0.035) compared with those with an ABI above 0.7. The remaining patient factors produced no statistically significant differences in survivorship, odds of failure, or HRs. No patient factors were associated with increased risk of mortality. These results suggest that patients who undergo TKA with an ABI below 0.7 are at increased risk for reoperation and have shorter reoperation free survival.

The Cost-Effectiveness of Platelet-Rich Plasma Injections for Knee Osteoarthritis: A Markov Decision Analysis

BACKGROUND

Use of platelet-rich-plasma (PRP) injections for treating knee osteoarthritis has increased over the past decade. We used cost-effectiveness analysis to evaluate the value of PRP in delaying the need for total knee arthroplasty (TKA).

METHODS

We developed a Markov model to analyze the baseline case: a 55-year-old patient with Kellgren-Lawrence grade-II or III knee osteoarthritis undergoing a series of 3 PRP injections with a 1-year delay to TKA versus a TKA from the outset. Both health-care payer and societal perspectives were included. Transition probabilities were derived from systematic review of 72 studies, quality-of-life (QOL) values from the Tufts University Cost-Effectiveness Analysis Registry, and individual costs from Medicare reimbursement schedules. Primary outcome measures were total costs and quality-adjusted life years (QALYs), organized into incremental cost-effectiveness ratios (ICERs) and evaluated against willingness-to-pay thresholds of $50,000 and $100,000. One and 2-way sensitivity analyses were performed as well as a probabilistic analysis varying PRP-injection cost, TKA delay intervals, and TKA outcomes over 10,000 different simulations.

RESULTS

From a health-care payer perspective, PRP resulted in 14.55 QALYs compared with 14.63 for TKA from the outset, with total health-care costs of $26,619 and $26,235, respectively. TKA from the outset produced a higher number of QALYs at a lower cost, so it dominated. From a societal perspective, PRP cost $49,090 versus $49,424 for TKA from the outset. The ICER for TKA from the outset was $4,175 per QALY, below the $50,000 willingness-to-pay threshold. Assuming the $728 published cost of a PRP injection, no delay time that was <10 years produced a cost-effective course. When the QOL value was increased from the published value of 0.788 to >0.89, PRP therapy was cost-effective with even a 1-year delay to TKA.

CONCLUSIONS

When considering direct and unpaid indirect costs, PRP injections are not cost-effective. The primary factor preventing PRP from being cost-effective is not the price per injection but rather a lack of established clinical efficacy in relieving pain and improving function and in delaying TKA. PRP may have value for higher-risk patients with high perioperative complication rates, higher TKA revision rates, or poorer postoperative outcomes.

LEVEL OF EVIDENCE

Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Does Circumferential Patellar Denervation Result in Decreased Knee Pain and Improved Patient-reported Outcomes in Patients Undergoing Nonresurfaced, Simultaneous Bilateral TKA?

BACKGROUND

Anterior knee pain, which has a prevalence of 4% to 49% after TKA, may be a cause of patient dissatisfaction after TKA. To limit the occurrence of anterior knee pain, patellar denervation with electrocautery has been proposed. However, studies have disagreed as to the efficacy of this procedure.Questions/purposes We evaluated patients undergoing bilateral, simultaneous TKA procedures without patellar resurfacing to ask: (1) Does circumferential patellar cauterization decrease anterior knee pain (Kujala score) postoperatively compared with non-cauterization of the patella? (2) Does circumferential patellar cauterization result in better functional outcomes based on patient report (VAS score, Oxford knee score, and Knee Injury and Osteoarthritis Outcome Score) than non-cauterization of the patella? (3) Is there any difference in the complication rate (infection, patellar maltracking, fracture, venous thromboembolism, or reoperation rate) between cauterized patellae and non-cauterized patellae?

METHODS

Seventy-eight patients (156 knees) were included in this prospective, quasi-randomized study, with each patient serving as his or her own control. Patellar cauterization was always performed on the right knee during simultaneous, bilateral TKA. Five patients (6%) were lost to follow-up before the 2-year minimum follow-up interval. A single surgeon performed all TKAs using the same type of implant, and osteophyte excision was performed in all patellae, which were left unresurfaced. Patellar cauterization was performed at 2 mm to 3 mm deep and approximately 5 mm circumferentially away from the patellar rim. The preoperative femorotibial angle and degree of osteoarthritis (according to the Kellgren-Lawrence grading system) were measured. Restoration of the patellofemoral joint was assessed using the anterior condylar ratio. Clinical outcomes, consisting of clinician-reported outcomes (ROM and Kujala score) and patient-reported outcomes (VAS pain score, Oxford knee score, and Knee Injury and Osteoarthritis Outcome Score), were evaluated preoperatively and at 1 month and 2 years postoperatively. Preoperatively, the radiologic severity of osteoarthritis, based on the Kellgren-Lawrence classification, was not different between the two groups, nor were the baseline pain and knee scores. The mean femorotibial angle of the two groups was also comparable: 189° ± 4.9° and 191° ± 6.3° preoperatively (p = 0.051) and 177° ± 2.9° and 178° ± 2.1° postoperatively (p = 0.751) for cauterized and non-cauterized knees, respectively. The preoperative (0.3 ± 0.06 versus 0.3 ± 0.07; p = 0.744) and postoperative (0.3 ± 0.06 versus 0.2 ± 0.07; p = 0.192) anterior condylar ratios were also not different between the cauterized and non-cauterized groups.

RESULTS

At the 2-year follow-up interval, no difference was observed in the mean Kujala score (82 ± 2.9 and 83 ± 2.6 for cauterized and non-cauterized knees, respectively; mean difference 0.3; 95% confidence interval, -0.599 to 1.202; p = 0.509). The mean VAS pain score was 3 ± 0.9 in the cauterized knee and 3 ± 0.7 in the non-cauterized knee (p = 0.920). The mean ROM was 123° ± 10.8° in the cauterized knee and 123° ± 10.2° in the non-cauterized knee (p = 0.783). There was no difference between cauterized and non-cauterized patellae in the mean Knee Injury and Osteoarthritis Outcome Score for symptoms (86 ± 4.5 versus 86 ± 3.9; p = 0.884), pain (86 ± 3.8 versus 86 ± 3.6; p = 0.905), activities (83 ± 3.2 versus 83 ± 2.8; p = 0.967), sports (42 ± 11.3 versus 43 ± 11.4; p = 0.942), and quality of life (83 ± 4.9 versus 83 ± 4.7; p = 0.916), as well as in the Oxford knee score (40 ± 2.1 versus 41 ± 1.9; p = 0.771). Complications were uncommon and there were no differences between the groups (one deep venous thromboembolism in the cauterized group and two in the control group; odds ratio 0.49, 95% CI, 0.04-5.56; p = 0.57).

CONCLUSIONS

Patellar cauterization results in no difference in anterior knee pain, functional outcomes, and complication rates compared with non-cauterization of the patella in patients who undergo non-resurfaced, simultaneous, bilateral, primary TKA with a minimum of 2 years of follow-up. We do not recommend circumferential patellar cauterization in non-resurfaced patellae in patients who undergo TKA.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Total Knee Arthroplasty in Patients with Prior Femoral and Tibial Fractures: Outcomes and Risk Factors for Surgical Site Complications and Reoperations

Objective

To investigate the outcomes of total knee arthroplasty (TKA) in patients with a prior femoral or tibial fracture, and identify the risk factors for surgical site complications and reoperations.

Methods

Seventy‐one TKAs performed in 71 patients with a prior tibial or femoral fracture between January 2005 and December 2016 were reviewed retrospectively. Forty males (40 knees) and 31 females (31 knees) were included. The mean age at the time of TKA was 59.2 (range, 29–83) years. Outcomes were assessed using the Knee Society score before surgery and at the final follow‐up visit. The patients' satisfaction rates were evaluated. Complications and reoperations were recorded by clinical and radiographic assessment. Logistic regression analysis was used to identify the risk factors for surgical site complications and reoperations.

Results

The median follow‐up period was 4.7 (range, 3.2–7.1) years. The median knee range of motion increased from 90° preoperatively to 110° at the latest follow‐up. The Knee Society knee score and function score improved from 35 (30, 40) and 40 (30, 50) to 90 (82, 93) and 90 (65, 100), respectively. The degree of overall satisfaction after TKA surgery was very satisfied in 41 patients, satisfied in 20 patients, neutral in four patients, dissatisfied in four patients, and very dissatisfied in two patients. The overall satisfaction (very satisfied and satisfied) rate was 85.9% (61 knees). Twelve knees (16.9%) had 19 surgical site complications. Six knees (8.3%) underwent reoperations, including one revision due to periprosthetic joint infection, one debridement and implant retention for superficial infection, two debridements for delayed wound healing, one open reduction and internal fixation for supracondylar fracture, and one re‐fixation and bone grafting for hardware failure after a combined femoral shaft osteotomy and TKA. Preoperative patella baja was diagnosed in 12 knees, and was identified as a risk factor for surgical site complications and reoperations.

Conclusions

TKA for post‐fracture osteoarthritis significantly relieved pain and improved function, but the incidence of surgical site complications and reoperations was high. Preoperative patella baja was a risk factor for surgical site complications and reoperations.

Higher mid-term revision rates of posterior stabilized compared with cruciate retaining total knee arthroplasties: 133,841 cemented arthroplasties for osteoarthritis in the Netherlands in 2007-2016

Background and purpose - The preference for a cruciate retaining (CR) or posterior stabilized (PS) TKA (total knee arthroplasty) system varies greatly between Dutch hospitals, independent of patient characteristics. We examined mid-term revision rates for men and women of different age categories. Patients and methods - We included all 133,841 cemented fixed-bearing primary CR or PS TKAs for osteoarthritis reported in the Dutch Arthroplasty Register (LROI) in 2007-2016. Revision procedures were defined as minor when only insert and/or patella were revised and as major when fixed components (tibia and femur) were revised or removed. 8-year all-cause revision rates of CR and PS TKAs were calculated using competing-risk analyses. Cox-regression analyses were performed, adjusted for age at surgery, sex, ASA -score, and previous operations. Results - PS TKAs were 1.5 (95% CI 1.4-1.6) times more likely to be revised within 8 years of the primary procedure, compared with CR TKAs. When stratified for sex and age category, 8-year revision rate of PS TKAs in men <60 years was 13% (CI 11-15), compared to 7.2% (CI 6.1-8.5) of CR TKAs. Less prominent differences were found in older men and women. For men <60 years differences were found for minor (CR 1.8% (CI 1.4-2.5); PS 3.7% (CI 3.0-4.7)) and major revisions (CR 4.2% (CI 3.3-5.3); PS 7.0% (CI 5.6-8.7)). Interpretation - Patients who received a cemented fixed-bearing primary PS TKA for osteoarthritis are more likely to undergo either a minor or a major revision within 8 years. This is especially prominent for younger men.

Mid-term survivorship and clinical outcomes of the Avon patellofemoral joint replacement

BACKGROUND

We present the largest series of Avon patellofemoral joint (PFJ) replacements outside of the design centre. There is discussion over its efficacy and usefulness. We report an independent opinion of its indications, survivorship and outcomes.

METHODS

We prospectively collected demographic data and patient reported outcome measures (PROM's) on our cohort of Avon Patellofemoral replacements since its adoption in our unit in 2003 until 2014. We performed a retrospective review of radiographs.

RESULTS

We performed 103 PFJ replacements in 85 patients, 36 were male (mean age 61 - range 34 to 78) and 67 female (mean age 60 - range 38 to 82), mean follow up time was 5.6years (range 2.9 to 14.2years) with 93 implants still in situ. Their mean post-operative Oxford Knee Score was 36 (range seven to 48). There were nine conversions to TKR for disease progression and one revision of a femoral component for trochlear malpositioning. Mean time to revision was 2.9years (1.0 to 6.0years). Radiographic evidence of progression on Kellgren and Lawrence score in the un-replaced compartments was demonstrated in 23% of cases with imaging available. The Avon PFJ replacement delivers reproducible and effective pain relief and function to patients with isolated patellofemoral osteoarthritis. We believe PFJ replacement has an important role to play, and we will continue to perform this procedure for a carefully selected group of patients. Conversion to TKR does not and should not be regarded as failure of the index operation.

Long-term outcomes of over 8,000 medial Oxford Phase 3 Unicompartmental Knees-a systematic review

Background and purpose - There is debate as to the relative merits of unicompartmental and total knee arthroplasty (UKA, TKA). Although the designer surgeons have achieved good results with the Oxford UKA there is concern over the reproducibility of these outcomes. Therefore, we evaluated published long-term outcomes of the Oxford Phase 3 UKA. Patients and methods - We searched databases to identify studies reporting ≥10 year outcomes of the medial Oxford Phase 3 UKA. Revision, non-revision, and re-operation rates were calculated per 100 component years (% pa). Results - 15 studies with 8,658 knees were included. The annual revision rate was 0.74% pa (95% CI 0.67-0.81, n = 8,406) corresponding to a 10-year survival of 93% and 15-year survival of 89%. The non-revision re-operation rate was 0.19% pa (95% CI 0.13-0.25, n = 3,482). The re-operation rate was 0.89% pa (95% CI 0.77-1.02, n = 3,482). The most common causes of revision were lateral disease progression (1.42%), aseptic loosening (1.25%), bearing dislocation (0.58%), and pain (0.57%) (n = 8,658). Average OKS scores were 40 at 10 years (n = 3,417). The incidence of medical complications was 0.83% (n = 1,443). Interpretation - Very good outcomes were achieved by both designer and non-designer surgeons. The PROMs, medical complication rate, and non-revision re-operation rate were better than those found in meta-analyses and publications for TKA but the revision rate was higher. However, if failure is considered to be all re-operations and not just revisions, then the failure rate of UKA was less than that of TKA.

Closed Incision Negative Pressure Therapy Effects on Postoperative Infection and Surgical Site Complication After Total Hip and Knee Arthroplasty

BACKGROUND

The aim of this study is to determine whether negative pressure wound therapy, used prophylactically in clean surgical incisions, reduces surgical site infection, hematoma, and seroma after total joint replacement.

METHODS

A single center, open-label study with a prospective cohort of patients undergoing primary total knee arthroplasty or total hip arthroplasty treated with closed incision negative pressure therapy (ciNPT) of clean surgical wounds was conducted. One hundred ninety-six incisions treated with ciNPT in 192 patients were compared with a historical control group of 400 patients treated with traditional gauze dressing. The rates of clinically significant hematoma, seroma, dehiscence, surgical site infection, and complication were compared using univariate analyses and multiple logistic regression.

RESULTS

The rate of deep infection was unchanged in the ciNPT group compared with control (1.0% vs 1.25%); however, the overall rate of infection (including superficial wound infection) decreased significantly (3.5% vs 1.0%, P = .04). Overall complication rate was lower in the ciNPT group than controls (1.5% vs 5.5%, P = .02). Upon logistic regression, only treatment group was associated with complication; patients treated with ciNPT were about 4 times less likely to experience a surgical site complication compared with control (P = .0277, odds ratio 4.251, 95% confidence interval 1.172-15.414).

CONCLUSION

ciNPT for total knee arthroplasty and total hip arthroplasty in a comprehensive patient population reduced overall incidence of complication, but did not significantly impact the rate of deep infection. Further research to determine clinical and economic advantages of routine use of ciNPT in total joint arthroplasty is warranted.

[Anterior knee pain after total knee arthroplasty : Causes, diagnosis and treatment]

BACKGROUND

Anterior knee pain is one of the most common complications after total knee arthroplasty. An incidence of up to 30 % has been reported in peer-reviewed studies.

TARGET

The purpose of this study was to systematically review the literature and to identify determinants that have been analyzed with regard to anterior knee pain.

CAUSES

Patient- and knee-specific characteristics, prosthetic designs and operative techniques are addressed as well as functional and neurologic determinants. Instability, increased contact pressure in the patellofemoral joint and patella maltracking due to malrotation of components, offset errors, ligament insufficiencies or patella baja are mechanical reasons for anterior knee pain. Functional causes include pathologic gait patterns, quadriceps imbalance and dynamic valgus. They have to be differentiated from infectious and inflammatory causes as well as soft tissue impingement, arthrofibrosis and neurologic diseases.

TREATMENT

A differentiated treatment algorithm is recommended. Often conservative treatment options exist, however, particularly with most mechanical causes revision surgery is necessary.

Contemporary failure aetiologies of the primary, posterior-stabilised total knee arthroplasty

Aims

The number of revision total knee arthroplasties (TKA) that are performed is expected to increase. However, previous reports of the causes of failure after TKA are limited in that they report the causes at specific institutions, which are often dependent on referral patterns. Our aim was to report the most common indications for re-operations and revisions in a large series of posterior-stabilised TKAs undertaken at a single institution, excluding referrals from elsewhere, which may bias the causes of failure.

Patients and Methods

A total of 5098 TKAs which were undertaken between 2000 and 2012 were included in the study. Re-operations, revisions with modular component exchange, and revisions with non-modular component replacement or removal were identified from the medical records. The mean follow-up was five years (two to 12).

Results

The Kaplan-Meier ten-year survival without a re-operation, modular component revision and non-modular component revision was 95.7%, 99.3% and 95.3%, respectively. The most common indications for a re-operation were: post-operative stiffness (58%), delayed wound healing (21%), and patellar clunk (11%). The indications for isolated modular component revision were acute periprosthetic joint infection (PJI) (64%) and instability (36%). The most common indications for non-modular component revision were chronic PJI (52%), aseptic loosening (17%), periprosthetic fracture (10%), and instability (10%).

Conclusion

Post-operative stiffness remains the most common indication for re-operation after TKA. Infection is the most common indication for modular and non-modular component revision. Aseptic loosening was not an uncommon cause of failure, however, it was much less common than in national registry and non-registry data. Focusing on posterior-stabilised TKAs initially performed at our institution allowed for an accurate assessment of the causes of failure in a contemporary specialty practice. Cite this article: Bone Joint J 2017;99-B:647–52.

Improved Survival of Computer-Assisted Unicompartmental Knee Arthroplasty: 252 Cases With a Minimum Follow-Up of 5 Years

BACKGROUND

Unicompartmental knee arthroplasty (UKA) is an underutilized implant for medial tibiofemoral arthritis despite proven benefits in performance and reduced complications. This is likely related to registry recorded higher revision rates compared with total knee arthroplasty. It is our feeling that better component alignment resulting from the usage of computer-assisted surgery should improve longer-term functional results and survival of UKAs.

METHODS

Between August 2003 and June 2007, 265 medial UKAs were performed in 264 consecutive patients using navigation.

RESULTS

Eighty-eight women and 176 men with an average age of 51.7 (±4.63) years were assessed for function and survival over a follow-up period of 92.6 (63-120) months (7.7 years). The final survival rate over 5 years for this cohort was 97.6% at 5 years.

CONCLUSION

We conclude that computer-assisted UKA, to treat medial tibiofemoral joint arthritis, produces 5-year survival rates that are comparable with total knee arthroplasty.

Diagnostic Algorithm for Residual Pain After Total Knee Arthroplasty

Although total knee arthroplasty is a successful and cost-effective procedure, patient dissatisfaction remains as high as 50%. Postoperative residual knee pain after total knee arthroplasty, with or without crepitation, is a major factor that contributes to patient dissatisfaction. The most common location for residual pain after total knee arthroplasty is anteriorly. Because residual pain has been associated with an un-resurfaced patella, this review includes only registry data and total knee arthroplasty with patella replacement. Some suggest that the pathogenesis of residual knee pain may be related to mechanical stimuli that activate free nerve endings around the patellofemoral joint. Various etiologies have been implicated in residual pain, including (1) low-grade infection, (2) midflexion instability, and (3) component malalignment with patellar maltracking. Less common causes include (4) crepitation and patellar clunk syndrome; (5) patellofemoral symptoms, including overstuffing and avascular necrosis of the patella; (6) early aseptic loosening; (7) hypersensitivity to metal or cement; (8) complex regional pain syndrome; and (9) pseudoaneurysm. Because all of these conditions can lead to residual pain, identifying the etiology can be a difficult diagnostic challenge. Often, patients with persistent pain and normal findings on radiographs and laboratory workup may benefit from a diagnostic injection or further imaging. However, up to 10% to 15% of patients with residual pain may have unexplained pain. This literature review summarizes the findings on the causes of residual pain and presents a diagnostic algorithm to facilitate an accurate diagnosis for residual pain after total knee arthroplasty.

Does a new implant design with more physiological kinematics provide better results after knee arthroplasty?

BACKGROUND

Improved knee kinematics is one of the major goals to obtain better satisfaction after total knee arthroplasty. This study examined whether a guided motion knee design improves functional outcome and satisfaction as compared to a conventional design.

METHODS

In a retrospective manner, from January 2005 to December 2008, patients with two different kinematic TKA designs were enrolled. The 150 patients were divided into two groups: guided motion group (77) with kinematic design (Journey) and control group (73) with no kinematic design (LCS). All the patients had the same surgical technique and postoperative protocols. The functional and radiographic results were interpreted with the Hospital for Special Surgery (HSS) knee score and WOMAC score.

RESULTS

After a mean follow-up of 84.2months, the guided motion group had higher mean postoperative range of motion (p=0.022), functional status in the WOMAC function subscale (p=0.002), but had higher residual pain in the WOMAC pain subscale (p=0.018 and p=0.013) and higher iliotibial band syndrome incidence (6.6% vs 0%; p=0.02). There were no significant differences in HSS score between the two groups. No differences were seen between groups in patient satisfaction in the WOMAC total score (p=0.46) and survival rate.

CONCLUSION

The guided motion design can improve functional status according to WOMAC but not to HSS knee scores. Poorer pain scores and no higher patient satisfaction were observed with this kinematic design.

The epidemiology of failure in total knee arthroplasty

Total knee arthroplasty (TKA) is a cost effective and extremely successful operation. As longevity increases, the demand for primary TKA will continue to rise. The success and survivorship of TKAs are dependent on the demographics of the patient, surgical technique and implant-related factors.

Currently the risk of failure of a TKA requiring revision surgery ten years post-operatively is 5%.

The most common indications for revision include aseptic loosening (29.8%), infection (14.8%), and pain (9.5%). Revision surgery poses considerable clinical burdens on patients and financial burdens on healthcare systems.

We present a current concepts review on the epidemiology of failed TKAs using data from worldwide National Joint Registries.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):105–12.

Knee arthroplasty and lawsuits: the experience in France

PURPOSE

Data regarding knee arthroplasty and lawsuit are scarce. With the expected increase in knee arthroplasty over the next 25 years, the number of claims might follow the same trend. Therefore, the most frequent causes of litigation after knee arthroplasty in France, and what is considered as malpractice by the expert, were determined.

METHODS

Over 8-year period, data gathered from a French private insurance company specializing in malpractice for private practitioners were analyzed. Demographics, type of knee arthroplasty, reason for claim, details of the legal procedure and the expert's decision were reviewed.

RESULTS

One hundred and five claims were processed by four jurisdictions. Most of the cases concerned primary total knee arthroplasty. Surgeons and anesthesiologists were charged in 84 and 16 % of claims, respectively. The most frequent causes of litigation were infection, neurological deficit and unsatisfactory result, whereas the most common reasons for the surgeon's liability, as stated by the expert, were delay in diagnosis or treatment of a complication, infection and technical error.

CONCLUSION

Our findings show that frequent complications are not those which raise most of the claims. Patients sue the surgeon when the outcome of the surgery is different from what they were expecting. An unsatisfactory result, according to the patient's point of view, is the second most frequent cause of claim.

LEVEL OF EVIDENCE

IV, Economic and Decision Analysis. See the Guidelines for Authors for a complete description of levels of evidence.

Risk Factors for Recurrence of Periprosthetic Knee Infection

We retrospectively reviewed 110 patients who underwent two-stage revision surgery in order to identify potential risk factors for recurrence of periprosthetic infection. We found that patients with inflammatory arthritis (P=0.0125), perioperative hematoma formation (P=0.0422), wound dehiscence (P=0.042), and those who are chronic Staphylococcus carriers (P=0.0177) were associated with an increased incidence of re-infection. The duration of intravenous antibiotic therapy less than 6 weeks was associated with a reduced risk of reinfection to greater than 6 weeks (P=0.03). Multivariate analysis indicated that wound dehiscence (odds ratio [OR], 5.119; 95% confidence interval [CI], 1.367-19.17), and Staphylococcus carriers (OR, 11.419; 95% CI, 1.376-94.727) are significant predictors of recurrence (P=0.0153 and 0.0241, respectively).

Does patellar denervation reduce post-operative anterior knee pain after total knee arthroplasty?

PURPOSE

The effectiveness of patellar denervation in reducing anterior knee pain and improving patient satisfaction and quality of life after total knee arthroplasty (TKA) is still controversial. A meta-analysis was conducted to try to settle the controversy.

METHODS

The electronic databases PubMed, Web of Science, Embase, and Cochrane Library were systematically searched. Of 374 papers identified, seven randomised controlled trials involving 898 patients (983 knees) were eligible for data extraction and meta-analysis.

RESULTS

Analysis showed that patellar denervation can significantly improve clinical outcomes for the first 12 months of follow-up after TKA, including anterior knee pain incidence (P = 0.008), visual analogue scale score (P < 0.001), patellar score (P < 0.001), Knee Society Score (P = 0.03), Knee Society Score function score (P = 0.03), and knee range of motion (P = 0.008). However, no statistical significance in outcomes was found between the patellar denervation group and no-denervation group for any of those parameters after 12 months of follow-up.

CONCLUSION

The best currently available evidence suggests that patellar denervation can significantly reduce anterior knee pain incidence and improve early clinical outcomes after TKA. However, after a prolonged period of follow-up, this advantage seems to disappear. Even so, the use of patellar denervation in primary TKA is recommended because it is safe and produces good early clinical outcomes.

LEVEL OF EVIDENCE

Therapeutic study, Level II.

The role of hinges in primary total knee replacement

The use of hinged implants in primary total knee replacement (TKR) should be restricted to selected indications and mainly for elderly patients. Potential indications for a rotating hinge or pure hinge implant in primary TKR include: collateral ligament insufficiency, severe varus or valgus deformity (>20°) with necessary relevant soft-tissue release, relevant bone loss including insertions of collateral ligaments, gross flexion-extension gap imbalance, ankylosis, or hyperlaxity. Although data reported in the literature are inconsistent, clinical results depend on implant design, proper technical use, and adequate indications. We present our experience with a specific implant type that we have used for over 30 years and which has given our elderly patients good mid-term results. Because revision of implants with long cemented stems can be very challenging, an effort should be made in the future to use shorter stems in modular versions of hinged implants.

Do various factors affect the frequency of manipulation under anesthesia after primary total knee arthroplasty?

BACKGROUND

One of the most important goals of primary total knee arthroplasty (TKA) is to achieve a functional range of motion (ROM). However, up to 20% of patients fail to do so, which can impair activities of daily living.

QUESTIONS/PURPOSES

The purpose of this study was to evaluate the effect of various (1) demographic factors; (2) comorbidities; and (3) knee-specific factors on the frequency of manipulation under anesthesia, which was used as an indicator of knee stiffness after a primary TKA.

METHODS

We evaluated the registries of two high-volume centers and reviewed all 3182 TKAs that were performed between 2005 and 2011 to identify all patients who had undergone manipulation under anesthesia (MUA). A total of 156 knees in 133 patients underwent MUA after an index arthroplasty. These patients were compared in a one-to-four ratio with a group of patients with satisfactory ROM drawn from the same database who met prespecified criteria and who had not undergone MUA. Effects of various factors, including age, sex, body mass index, race, comorbidities, and the underlying cause of knee arthritis, were compared between these two cohorts using multivariable logistic regressions.

RESULTS

After controlling for various confounding, nonwhite race was associated with an increase (odds ratio [OR], 2.01; p=0.03), and age≥65 years (OR, 0.17; 95% confidence interval [CI], 0.04-0.74; p=0.0179) was associated with a reduction in the incidence of MUA. In comorbidities, diabetes (OR, 1.72; 95% CI, 1.02-2.32; p=0.03), high cholesterol levels (OR, 2.70; p=0.03), and tobacco smoking (OR, 1.59; 95% CI, 1.03-2.47; p=0.03) were associated with an increase in frequency of MUA. In knee-specific factors, preoperative knee ROM of less than 100° (OR, 0.80; p<0.0001) and knee osteonecrosis (p=3.61; 95% CI, 1.29-10.1; p=0.014) were associated with increased frequency of MUA.

CONCLUSIONS

We identified several demographic, medical, and knee-specific factors that were associated with poor postoperative ROM in our patients undergoing TKA. Patients who have multiple risk factors may benefit from preoperative counseling to set realistic ROM expectations.

LEVEL OF EVIDENCE

Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Return to theatre for elective hip and knee replacements

The aim of this study was to define return to theatre (RTT) rates for elective hip and knee replacement (HR and KR), to describe the predictors and to show the variations in risk-adjusted rates by surgical team and hospital using national English hospital administrative data.

We examined information on 260 206 HRs and 315 249 KRs undertaken between April 2007 and March 2012. The 90-day RTT rates were 2.1% for HR and 1.8% for KR. Male gender, obesity, diabetes and several other comorbidities were associated with higher odds for both index procedures. For HR, hip resurfacing had half the odds of cement fixation (OR = 0.58, 95% confidence intervals (CI) 0.47 to 0.71). For KR, unicondylar KR had half the odds of total replacement (OR = 0.49, 95% CI 0.42 to 0.56), and younger ages had higher odds (OR = 2.23, 95% CI 1.65 to 3.01) for ages < 40 years compared with ages 60 to 69 years). There were more funnel plot outliers at three standard deviations than would be expected if variation occurred on a random basis.

Hierarchical modelling showed that three-quarters of the variation between surgeons for HR and over half the variation between surgeons for KR are not explained by the hospital they operated at or by available patient factors. We conclude that 90-day RTT rate may be a useful quality indicator for orthopaedics.

Cite this article: Bone Joint J 2014; 96-B:1663–8.

Adverse outcomes after total and unicompartmental knee replacement in 101,330 matched patients: a study of data from the National Joint Registry for England and Wales

BACKGROUND

Total knee replacement (TKR) or unicompartmental knee replacement (UKR) are options for end-stage osteoarthritis. However, comparisons between the two procedures are confounded by differences in baseline characteristics of patients undergoing either procedure and by insufficient reporting of endpoints other than revision. We aimed to compare adverse outcomes for each procedure in matched patients.

METHODS

With propensity score techniques, we compared matched patients undergoing TKR and UKR in the National Joint Registry for England and Wales. The National Joint Registry started collecting data in April 1, 2003, and is continuing. The last operation date in the extract of data used in our study was Aug 28, 2012. We linked data for multiple potential confounders from the National Health Service Hospital Episode Statistics database. We used regression models to compare outcomes including rates of revision, revision/reoperation, complications, readmission, mortality, and length of stay.

FINDINGS

25,334 UKRs were matched to 75,996 TKRs on the basis of propensity score. UKRs had worse implant survival both for revision (subhazard ratio [SHR] 2·12, 95% CI 1·99–2·26) and for revision/reoperation (1·38, 1·31–1·44) than TKRs at 8 years. Mortality was significantly higher for TKR at all timepoints than for UKR (30 day: hazard ratio 0·23, 95% CI 0·11–0·50; 8 year: 0·85, 0·79–0·92). Length of stay, complications (including thromboembolism, myocardial infarction, and stroke), and rate of readmission were all higher for TKR than for UKR.

INTERPRETATION

In decisions about which procedure to offer, the higher revision/reoperation rate of UKR than of TKR should be balanced against a lower occurrence of complications, readmission, and mortality, together with known benefits for UKR in terms of postoperative function. If 100 patients receiving TKR received UKR instead, the result would be around one fewer death and three more reoperations in the first 4 years after surgery.

FUNDING

Royal College of Surgeons of England and Arthritis Research UK.

Incidence of patellar clunk syndrome in fixed versus high-flex mobile bearing posterior-stabilized total knee arthroplasty

The geometry of the intercondylar box plays a significant role in the development of patellar clunk syndrome. We reviewed the incidence of patella clunk at mid-to-long-term follow-up of a rotating high-flex versus fixed bearing posterior stabilized TKA design. 188-mobile and 223-fixed bearing TKAs were reviewed for complications, incidence of patellar clunk, treatment, recurrence rates, range of motion, and patient satisfaction. Patellar clunk developed in 22 knees in the mobile (11.7%) and in 4 (1.8%) in the fixed bearing group (P<0.001). 23 out of 26 cases resolved with a single arthroscopic treatment and 2 resolved with a second procedure. The mean postoperative range of motion was 122.4°. All but one patient reported overall satisfaction with the index procedure. In contrast with other recent studies we found a significant incidence of patellar clunk in high-flex mobile bearings. Despite the high rate of patellar clunk syndrome, overall patients did well and were satisfied with their outcomes.

Effect of immediate postoperative portable radiographs on reoperation in primary total knee arthroplasty

Cost-containment strategies are of increasing importance in total knee arthroplasty (TKA). Obtaining immediate postoperative radiographs following primary TKA is common practice, but their usefulness is controversial. The goal of this study was to evaluate the effect of immediate postoperative radiographs on reoperation within 60 days, assess film quality, and determine the cost associated with these radiographs. Using a billing registry at the authors' institution, the number of TKAs performed from 2000 to 2011 was determined. Of those, the authors determined which had undergone reoperation within 60 days. They evaluated those who had immediate postoperative radiographs following their primary TKA, and determined those who had been reoperated on as a result of information obtained from these radiographs. Of 6603 patients who underwent primary TKA from 2000 to 2011, 136 (2%) underwent reoperation within the first 60 days. The causes leading to reoperation were arthrofibrosis, infection, wound-healing complications, and hematoma. Of the 136 who underwent reoperation, 76 had immediate postoperative radiographs. None of them underwent reoperation as a result of findings noted in the radiographs. Of the radiographs reviewed, only 43% were deemed adequate by predetermined criteria. The results of the current study demonstrate that these radiographs do not affect the decision for reoperations that occur within 60 days of the index procedure. Although there may be a benefit to immediate postoperative radiographs in selected clinical situations, the decision for routine use needs to be weighed in light of significant cost and limited clinical usefulness.

Patellar clunk syndrome after total knee arthroplasty; risk factors and functional outcomes of arthroscopic treatment

This study reports the incidence, risk factors, and functional outcomes of the largest reported series of patients treated arthroscopically for patella clunk syndrome (PCS). All patients treated arthroscopically for PCS were identified. Patients were matched with controls by sex and date of surgery. Follow-up was conducted using SF-12 and WOMAC questionnaires. Operative notes and preoperative and postoperative radiographs were reviewed. Seventy-five knees in 68 patients were treated arthroscopically for PCS. Average follow-up was 4.2 years. Functional scores demonstrated no statistical difference. PCS patients had a significantly more valgus preoperative alignment, greater change in posterior femoral offset and smaller patellar component size. PCS is a relatively common complication following TKA. Arthroscopy yields functional results comparable to controls. Radiographic and technical factors are associated with PCS.

Why are total knee arthroplasties failing today--has anything changed after 10 years?

The purpose of this study was to determine the frequency and cause of failure after total knee arthroplasty and compare the results with those reported by our similar investigation conducted 10 years ago. A total of 781 revision TKAs performed at our institution over the past 10 years were identified. The most common failure mechanisms were: loosening (39.9%), infection (27.4%), instability (7.5%), periprosthetic fracture (4.7%), and arthrofibrosis (4.5%). Infection was the most common failure mechanism for early revision (<2 years from primary) and aseptic loosening was the most common reason for late revision. Polyethylene (PE) wear was no longer the major cause of failure. Compared to our previous report, the percentage of revisions performed for polyethylene wear, instability, arthrofibrosis, malalignment and extensor mechanism deficiency has decreased.

Can TKA design affect the clinical outcome? Comparison between two guided-motion systems

PURPOSE

In a retrospective comparative analysis in patients undergoing primary guided-motion total knee arthroplasty (TKA), the authors have evaluated whether different TKA implant design would influence the clinical and functional outcomes.

METHODS

Between 2007 and 2009, 227 computer-assisted primary TKAs were performed in 219 consecutive patients. Patients received one of the two different fixed-bearing guided-motion TKA designs assisted by navigation surgery: the Scorpio Non-Restrictive Geometry (NRG) knee system and the Journey Bi-Cruciate Stabilized (BCS) knee systems.

RESULTS

Data were available for 180 patients (187 knees). No significant differences were observed between the two groups with respect to preoperative demographic characteristics, range of motion (ROM) and radiographic knee alignment. At a mean follow-up of 29 months, the Journey BCS group had higher mean Knee Injury and Osteoarthritis Outcome Score (KOOS) in all subscales and a greater ROM than the Scorpio NRG group. This difference was statistically significant for the KOOS subscales of pain (p = 0.007) and knee-related quality of life (p = 0.045), as well as for postoperative ROM (p = 0.018). Considering the overall complications, 1 patient of Scorpio NRG group (0.5%) and 5 in Journey BCS (2.7%) had stiffness. Anterior knee pain was reported in 4 cases of Scorpio NRG group (2.1%). In the Journey BCS group were observed 2 cases (1.1%) of frontal plane instability and 1 case (0.5%) of synovitis pain.

CONCLUSIONS

The bearing geometry and kinematic pattern of different guided-motion prosthetic designs can affect the clinical-functional outcome and complications type in primary TKA.

LEVEL OF EVIDENCE

Clinical study, Level III.

Patellofemoral crepitation and clunk following modern, fixed-bearing total knee arthroplasty

Patellar crepitation and clunk (PCC) is an important and modifiable complication of total knee arthroplasty (TKA). We calculated the incidence of PCC using a modern fixed-bearing TKA prosthesis, assessed whether PCC is associated with knee range of motion, and determined if there were any radiographic variables associated with the development of PCC in this prosthetic design. Five hundred seventy primary TKAs were evaluated after a mean follow-up of 24 months (range 12-81). Thirty-four knees developed PCC (6%); 6 required arthroscopic debridement. With each degree increase in the flexion angle, the likelihood of developing PCC increased by 4.2%. The incidence of PCC was low but increased with postoperative flexion ≥ 110°. No radiographic parameters were associated with the development of PCC.

Unplanned readmission after total joint arthroplasty: rates, reasons, and risk factors

BACKGROUND

There has been a major and alarming increase in readmission rates following total joint arthroplasty. With proposed changes in reimbursement policy, increased rates of unplanned readmission following arthroplasty will penalize providers. In particular, it has been proposed that specific complications--so-called "zero-tolerance" complications--are unacceptable and that their treatment will not qualify for reimbursement. The purpose of this study was to identify the incidence, causes, and risk factors for readmission following total joint arthroplasty.

METHODS

An institutional arthroplasty database was utilized to identify those patients undergoing total knee or hip arthroplasty from January 2004 through December 2008. A total of 10,633 admissions for primary arthroplasty (5207 knees and 5426 hips) were identified. The same database was used to identify patients requiring an unplanned readmission within ninety days of discharge. Multivariate logistic regression was utilized to determine the independent predictors of readmission within ninety days.

RESULTS

There were 591 unplanned readmissions within ninety days of discharge following 564 (5.3%) of the 10,633 admissions for total joint arthroplasty. The most common cause of readmission was joint-related infection, followed by stiffness. Black race, male sex, discharge to inpatient rehabilitation, increased duration of hospital stay, unilateral replacement, decreased age, decreased distance between home and the hospital, and total knee replacement were independent predictors of readmission within ninety days.

CONCLUSIONS

The high incidence of readmissions secondary to potential "zero-tolerance" events suggests that these are not easily preventable complications. In addition, longer hospitalization and discharge to an inpatient continued-care facility increased the risk of readmission.

Medial mobile bearing unicompartmental knee arthroplasty: early survivorship and analysis of failures in 1000 consecutive cases

Unicompartmental knee arthroplasty (UKA) is a less invasive treatment for medial gonarthrosis. However, registry data have demonstrated higher revision and early failure rates. The purpose of this study is to report the early survivorship and failure modes in a series of 1000 consecutive medial mobile bearing UKA. UKA patients with a minimum of 2 year follow-up or those meeting the study endpoint (UKA failure or death) were included. Demographic variables, pre and post-operative clinical variables, and mode of failure were analyzed. Eight hundred and thirty-nine knees were included in the analysis. Forty revisions were performed at an average of 23.1 months (range, 2.3-74.2) following UKA for a survivorship of 95.2%. Indications for revision were aseptic loosening (15), tibial collapse (7), mobile bearing dislocation (2), persistent pain (12), progression of disease (2), infection (1), and tibiofemoral instability (1). These results are from a single center and may not be comparable to those of larger reports such as national registries.

Anterior knee pain after total knee arthroplasty: a narrative review

Anterior knee pain is one of the most common causes of persistent problems after implantation of a total knee replacement. It can occur in patients with or without patellar resurfacing. As a result of the surgical procedure itself many changes can occur which may affect the delicate interplay of the joint partners in the patello-femoral joint. Functional causes of anterior knee pain can be distinguished from mechanical causes. The functional causes concern disorders of inter- and intramuscular coordination, which can be attributed to preoperative osteoarthritis. Research about anterior knee pain has shown that not only the thigh muscles but also the hip and trunk stabilising muscles may be responsible for the development of a dynamic valgus malalignment. Dynamic valgus may be a causative factor for patellar maltracking. The mechanical causes of patello-femoral problems after knee replacement can be distinguished according to whether they increase instability in the joint, increase joint pressure or whether they affect the muscular lever arms. These causes include offset errors, oversizing, rotational errors of femoral or tibial component, instability, maltracking and chondrolysis, patella baja and aseptic loosening. In these cases, reoperation or revision is often necessary.

Mortality and perioperative complications after unicompartmental knee arthroplasty

AIM OF STUDY

Unicompartmental knee arthroplasty (UKA) has been increasingly utilized over the past decade secondary to favorable reports of better range of motion, higher activity levels, and increased patient satisfaction compared with total knee arthroplasty (TKA). The aim of this study was to determine the 90-day incidence of perioperative complications and mortality of patients undergoing UKA.

METHODS

One thousand consecutive UKA in 828 patients were retrospectively reviewed. A retrospective review was performed to evaluate 90-day perioperative complication and mortality rates.

RESULTS

There were zero deaths during the study period. Twelve percent of surgeries were complicated by variances within the 90-day postoperative period. There was one deep venous thrombosis (0.1%) and no pulmonary emboli. Cardiovascular complications were infrequent. Three patients had a myocardial infarction (0.31%), one developed congestive heart failure (0.1%), one angina (0.1%), and three had arrhythmias (0.31%). Secondary procedures were performed in 15 patients during the follow-up period: seven were manipulations under anesthesia for arthrofibrosis, one was an arthroscopic removal of retained cement, one arthroscopic removal of a drain, one repeat wound closure after a dehiscence secondary to a fall, one open reduction internal fixation for a supracondylar femur fracture, three irrigation and debridement procedures for an aseptic hematoma, and one radical debridement with later successful conversion to a total knee arthroplasty for a periprosthetic infection.

CONCLUSION

This study supports the notion that UKA is a safe procedure that is associated with a low rate of mortality and serious post-operative complications.

The evolving incidence and reasons for re-operation after fixed-bearing PCL retaining total knee arthroplasty

PCL retaining fixed-bearing TKA is a highly successful operation with the need for more surgery occurring at the rate of approximately 0.4% per year over the first 27 years. The most common cause for revision surgery is related to polyethylene insert failure and accounts for approximately 50% of re-operations. Late metastatic infection is the next most frequent cause followed by patellar problems, late instability and component loosening in decreasing frequency. A myriad of rare miscellaneous problems can also occur.

The 2012 Chitranjan Ranawat award: intraarticular analgesia after TKA reduces pain: a randomized, double-blinded, placebo-controlled, prospective study

BACKGROUND

Postoperative pain after total knee arthroplasty remains one of the most important challenges facing patients undergoing this surgery. Providing a balance of adequate analgesia while limiting the functional impact of regional anesthesia and minimizing opioid side effects is critical to minimize adverse events and improve patient satisfaction.

QUESTIONS/PURPOSES

We asked whether bupivacaine delivered through an elastomeric device decreases the (1) patients' perception of pain after TKA; (2) narcotic consumption; and (3) narcotic-related side effects as compared with a placebo.

METHODS

In this prospective, double-blind, placebo-controlled study, all patients received standardized regional anesthesia, a preemptive and multimodal analgesic protocol, and a continuous intraarticular infusion at 5 mL/hour through an elastomeric infusion pump. The patients were randomized to receive either an infusion pump filled with (1) 300 mL of 0.5% bupivacaine, the experimental group (n = 75); or (2) 300 mL of 0.9% normal saline solution, the control group (n = 75). Data concerning postoperative pain levels through a visual analog scale, postoperative opioid consumption, opioid-related side effects, and complications were collected and analyzed.

RESULTS

Patients in the experimental group receiving the bupivacaine reported a reduction in pain levels in highest, lowest, and current visual analog scale scores compared with the placebo group on the first postoperative day and highest visual analog scale score on postoperative Day 2 along with a 33% reduction in opioid consumption on postoperative Day 2 and a 54% reduction on postoperative Day 3.

CONCLUSION

In patients undergoing TKA, continuous intraarticular analgesia provided an effective adjunct for pain relief in the immediate postoperative period without the disadvantages encountered with other analgesic methods.

Review article: Risk factors of infection following total knee arthroplasty

22 PubMed articles in English were identified using the key words: 'risk factors', 'infection', and 'primary total knee arthroplasty (TKA)'. The 10 most relevant articles were reviewed. In one study, obesity and diabetes were considered risk factors for infection following TKA. In another study, postoperative infection correlated with a history of open reduction and internal fixation, male gender, remnants of previous internal fixation material, and body mass index. In yet another study, the risk factors were (in decreasing order of significance): congestive heart failure, chronic pulmonary disease, preoperative anaemia, diabetes, depression, renal disease, pulmonary circulation disorders, obesity, rheumatologic disease, psychoses, metastatic tumour, peripheral vascular disease, and valvular disease.

Complications in total knee arthroplasty after high tibial osteotomy

The outcome of total knee arthroplasty (TKA) after high tibial osteotomy remains uncertain. Compared with primary TKA, the results in some studies are not significantly different. Others report adverse effects on the outcome. The purpose of this study was to determine (1) the middle- and long-term survival of TKA performed after high tibial osteotomy, (2) their clinical and radiographic results, and (3) what complications could be expected in this group of patients.The study group comprised 31 patients (34 knees) undergoing cemented TKA after high tibial osteotomy. Average follow-up was 8 years (range, 6-213 months). Survival of the TKA was estimated using the Kaplan-Meier method. Outcomes were documented using the Hospital for the Special Surgery score. The results showed that the Kaplan-Meier survival rate was 82% at 5 years and 76% at 10 years. Excellent and good clinical results were obtained in 67% of patients. Complications occurred in 12 (35%) knees: stiffness in 4, aseptic loosening in 2, patellofemoral subluxation in 1, instability in 1, inexplicable pain in 1, and deep infection in 3.Great care with technical details is necessary when high tibial osteotomy is indicated because a future conversion to TKA may occur.