PROMs in total knee replacement: analysis of negative outcomes

IntroductionNHS England uses the Oxford Knee Score (OKS) as part of patient-reported outcome measures (PROMs) to evaluate ‘health gains’ following total knee replacement. Policy makers use this to guide healthcare funding and resource allocation. Our study aims to undertake a qualitative and quantitative analysis of OKS among patients who experienced a negative outcome after a total knee replacement at our centre.Materials and methodsBetween April 2017-March 2018, 19 of 189 (10%) patients had a worsened OKS at our centre. We retrospectively and prospectively reviewed 14 of these patients. Structured telephone interviews with a repeat OKS were carried out in September 2019 (18–29 months post-operation).ResultsEight patients were female and the total age range was 57–95, mean average 75.6 (SD 9.9 years). Of 48 (higher scores meaning better outcomes), the average preoperative OKS was 24.2 and the average postoperative OKS at 6 months was 19.4 (decrease of 20%). The average postoperative OKS at 18–29 months was 35.6 (an increase of 83.5% from 6 months).DiscussionThe OKS was developed and validated over 20 years ago in Oxford. In our study, four patients asked for clarification of questions 4, 6 and 10 owing to ambiguous language. All 14 patients who had negative OKS outcomes had positive outcomes when retested after 18 months, depicting ‘health gains’ not conveyed in PROMs analysis.ConclusionThe OKS needs to be revalidated on current patient groups for accurate and reliable data. Further prospective studies should be undertaken on larger cohorts to understand the recovery course and whether PROMs should be carried out later.     

Patient perceptions regarding minimally invasive total knee replacement

Interest in minimally invasive total knee replacement has increased in recent years. This has occurred despite a lack of long-term data regarding complications and outcomes. The aim of this study was to explore patients’ opinions relating to this relatively new technique. A questionnaire-based study was performed using patients attending clinics of consultant orthopaedic surgeons with an interest in knee arthroplasty. Low complication rates and implant survival were the items of highest importance to patients followed by a shorter recovery period. The duration of hospital stay and length of scar were of less importance to patients. Forty percent of patients would wish to go ahead with the procedure despite the lack of long-term outcome data. Only a small proportion of patients appear to be willing to undergo the procedure despite a lack of long-term data. Before taking up newer treatment methods patients must be convinced of the potential benefits and should be made aware that no long-term outcomes are available, at present.     

Anterior knee pain following primary total knee arthroplasty

Despite improvements in technique and technology for total knee arthroplasty (TKA), anterior knee pain impacts patient outcomes and satisfaction. Addressing the prosthetic and surgical technique related causes of pain after TKA, specifically as it relates to anterior knee pain, can aid surgeons in addressing these issues with their patients. Design features of the femoral and patellar components which have been reported as pain generators include: Improper femoral as well as patellar component sizing or designs that result in patellofemoral stuffing; a shortened trochlear groove distance from the flange to the intercondylar box; and then surgical technique related issues resulting in: Lateral patellar facet syndrome; overstuffed patella/flange combination; asymmetric patellar resurfacing, improper transverse plane component rotation resulting in patellar subluxation/tilt. Any design consideration that allows impingement of extensor mechanism anatomical elements has the possibility of impacting outcome by becoming a pain generator. As the number of TKA procedures continues to increase, it is increasingly critical to develop improved, evidence based prostheses that maximize function and patient satisfaction while minimizing pain and other complications.     

Arthroscopy of the painful dysfunctional total knee replacement

Arthroscopy of the painful failed total knee arthroplasty has rarely been reported. The indications and results in terms of diagnosis and treatment of pathologic conditions in 13 knees after total knee arthroplasty are reviewed. Arthroscopy established the diagnosis for pain in 12 of 13 knees. Several problems were commonly encountered, including arthrofibrosis and fracture of the polyethylene button. Arthroscopic surgery for arthrofibrosis was successful in improving range of motion and knee-rating score.     

Physical activity after total knee arthroplasty: A critical review

Total knee arthroplasty (TKA) is the most commonly performed elective surgery in the United States. TKA typically improves functional performance and reduces pain associated with knee osteoarthritis. Little is known about the influence of TKA on overall physical activity levels. Physical activity, defined as “any bodily movement produced by skeletal muscles that results in energy expenditure”, confers many health benefits but typically decreases with endstage osteoarthritis. The purpose of this review is to describe the potential benefits (metabolic, functional, and orthopedic) of physical activity to patients undergoing TKA, present results from recent studies aimed to determine the effect of TKA on physical activity, and discuss potential sources of variability and conflicting results for physical activity outcomes. Several studies utilizing self-reported outcomes indicate that patients perceive themselves to be more physically active after TKA than they were before surgery. Accelerometry-based outcomes indicate that physical activity for patients after TKA remains at or below pre-surgical levels. Several different factors likely contributed to these variable results, including the use of different instruments, duration of follow-up, and characteristics of the subjects studied. Comparison to norms, however, suggests that daily physical activity for patients following TKA may fall short of healthy age-matched controls. We propose that further study of the relationship between TKA and physical activity needs to be performed using accelerometry-based outcome measures at multiple post-surgical time points.     

膝表面置换术在类风湿性膝关节炎和骨性膝关节炎的应用和比较

目的探讨膝关节表面置换术治疗类膝关节风湿性关节炎(RA)和膝关节骨性关节炎(OA)的临床疗效、安全性差异。方法自2010-01—2012-04采用膝关节表面置换术治疗68例(84膝)膝关节疾患,按照疾病类型分为OA组和RA组,对比分析2组手术时间、术中出血量、VAS评分、切口愈合时间、HSS单项评分及总分等。结果术后68例(84膝)获得平均47个月随访,随访期间无人工膝关节假体脱位。OA组手术时间、术中失血量、术后引流量及VAS评分显著低于RA组,差异有统计学意义(P0.05)。OA组术后1个月疼痛和HSS总分显著高于RA组,差异有统计学意义(P0.05),OA组术后1年和3年疼痛、功能、活动范围单项评分和HSS总分均显著高于RA组,差异有统计学意义(P0.05)。结论OA及RA人工全膝置换术后功能均有一定改善,与OA相比,RA患者术后近中期疗效相对较差,但远期疗效差异有待进一步研究。     

The painful total knee arthroplasty: Keys to diagnosis

As the prevalance of patients living with total knee replacements continues to rise we continue to see a significant portion of patients living with pain following their primary total knee arthroplasty. For some patients, the etiology of their pain following knee replacement is obvious, yet in many cases the cause of pain remains elusive and thus creates a significant burden for the patient and treating physician. In this review article we focus on common sources of pain following knee replacement and discuss keys to diagnosis. We also propose a unique clinical pathway algorithm to guide diagnostic work up and treatment options.     

Arthroscopy of symptomatic total knee replacements

Between December 1983 and August 1992, 21 knees in 19 patients with symptomatic total knee replacements were arthroscopically diagnosed. The average time between total knee replacement and arthroscopy was 20 months (ranging from 4 to 84 months). All patients were primary total knee replacements. Metal bars, 5 and 8 mm in diameter and 40 cm in length, were made for arthroscopic treatment of fibroarthrosis. Thirteen knees of 11 patients with a diagnosis of arthrofibrosis had an average improvement of 42° arc of motion 1 year after arthroscopic surgery. Three knees with an average of 15° increase of motion were determined to be failures. Another two patients had arthroscopic resection of fibrous bands with complete relief of patella pain. Among six patients who had revision of total knee replacements after arthroscopic diagnosis, four had wear in the metal backed patella components, and two had wear in the tibial insert and loosening of cementless patella component. An early diagnosis of implant failure under arthroscopic control was made, which easily allowed revision of the metal-backed patellar button before the development of metallosis and massive osteolysis caused by the marked wear of polyethylene. With the use of our specially made metal bars for treating arthrofibrosis, we could release the adhesion more easily and avoid damage of valuable arthroscopic instruments.     

Do bisphosphonates reduce early micromotion and Periprosthetic bone loss in total knee arthroplasty? A review of the evidence

Early micromotion of implant components and periprosthetic bone loss in patients undergoing total knee arthroplasty are thought to contribute to late aseptic loosening. In the pursuit of longer implant survival, the administration of bisphosphonates may be advocated as a means to buffer implants against microinstability and periprosthetic bone loss. A bibliographic search identified one metaanalysis and two randomised controlled trials dealing with this topic. Current evidence supports the hypothesis that the inhibiting effects of bisphosphonates on bone resorption reduce implant micromotion and periprosthetic bone loss at the one-year follow-up. Tested bisphosphonates include clodronate, pamidronate and alendronate. However, a decline in periprosthetic BMD is observed at the three-year follow-up following a sixmonth course of bisphosphonate administration. Length of follow-up in available studies is currently too short to determine whether bisphosphonates increase the longevity of implants. Furthermore, the optimal dose, modality and length of bisphosphonate administration have yet to be determined.     

全膝关节置换术后严重异位骨化与关节僵硬

[目的]探讨全膝关节置换术后严重异位骨化与关节僵硬的关系。[方法]对420例接受全膝关节置换术的患者随访,其中9例出现了Ⅲ级异位骨化,分别测量并记录该9例患者术后2周、12个月的疼痛评分和膝关节活动度,拍摄X线片,测量异位骨的大小。随机抽取9例无异位骨化的关节置换术后患者作为对照组,并测量疼痛评分及活动度。分别将异位骨化组和对照组的结果进行对比。[结果]关节置换术后Ⅲ级异位骨化的发病率为2.1%,X线片显示异位骨>5 cm,侵及股四头肌,引起关节疼痛。异位骨化组术后2周疼痛评分平均25.6分,关节最大伸直角度平均1.1°,最大屈曲角度119.1°,与对照组比较差异均无统计学意义(P>0.05)。异位骨化组术后12个月疼痛评分平均15.56分,低于术后2周(P<0.01),与对照组术后12个月(25分)比较有显著差异(P<0.01)。关节活动度:伸直6.1°,屈曲91.7°与术后2周和对照组术后12个月比较均有显著差异(P<0.01)。[结论]全膝关节置换术后Ⅲ级异位骨化可以导致关节疼痛和活动度受限,是术后关节僵硬的原因之一,严重影响置换术后临床效果。     

Surgical factors for total knee arthroplasty in younger patients

With improvements in implant modularity and polyethylene, it is important to assess the contemporary performance of cement vs. cementless fixation in total knee arthroplasty (TKA). Aseptic loosening is the most common indication for revision. Registry data indicates that the type of fixation (cemented, cementless, or hybrid) makes little difference in revision rates for younger patients (<55 years old). Regardless of the type of fixation, there is an opportunity for improvement. Attention to surgical factors, such as coronal alignment and cementing technique, can improve the survivorship of TKA.     

Minimum twelve-year follow-up of fixed- vs mobile-bearing total knee arthroplasty: Double blinded randomized trial

BackgroundTotal knee arthroplasty (TKA) with fixed-bearing (FB) implants have demonstrated impressive functional results and survival rates. Meanwhile, rotating-platform (RP) constructs have biomechanically shown to reduce polyethylene wear, lower the risk of component loosening, and better replicate anatomic knee motion. There is growing question of the clinical impact these design changes have long-term.Questions/purposes: The aim of this double-blinded prospective randomized trial was to compare function and implant survival in patients who received either FB or RP press-fit condylar Sigma (PFC Sigma, DePuy, Warsaw, IN) total knee replacements at a minimum follow-up of twelve years.Patients and methodsPatient reported outcome measures used included the functional Knee Society Score, Western Ontario and McMaster University Osteoarthritis Index (WOMAC) scores, Medical Outcomes Short Form-36 (SF-36) score, and satisfaction assessment on a four-point Likert scale. The data was collected from times preoperative, two-years, and final encounter (mean 13.95 years). A total of 28 RP and 19 FB knees (58.8%) were analyzed at the final follow-up.ResultsAmong all patients, KSS and WOMAC scores statistically improved from pre-op to 2-year, while KSS statistically worsened from 2-year to final follow-up. The RP group averaged better follow-up scores in all assessments at the final follow-up with exception of overall satisfaction. There was no statistically significant difference in the functional Knee Society Score, Short Form-36, WOMAC scores, patient satisfaction or implant survival between the two groups at any measured period.ConclusionsThe use of a fixed-bearing or rotating-platform design does not convey significant superiority in terms of function or implant longevity at a minimum twelve years after total knee arthroplasty.Level of evidenceLevel I, Experimental study, randomized controlled trial (RCT).     

Failed unicompartmental knee replacement to total knee replacement conversion: Can you achieve a primary outcome?

This review provides an overview of aetiology, diagnosis and management of failed UKRs and highlights key aspects of the decision making process and operative technique to ensure satisfactory outcome after UKR revision surgery.With correct diagnosis and management, in the majority of revision UKR cases outcome similar to primary TKR can be achieved. Unexplained pain, aseptic loosening, infection, progression of arthritis and bearing dislocation are the commonest reasons needing further intervention after UKR. Key messages are about how to reduce the revision risk, methods to critically analyze a painful UKR and when and how to revise a UKR.     

Unicompartmental knee replacement – Current perspectives

Unicompartmental knee replacement (UKR) is an effective treatment for end-stage, symptomatic unicompartmental osteoarthritis of the knee. However, certain aspects of the procedure are still debated. These areas of discussion include patient selection criteria, implant design and the discrepancy in survival rates between national registries and independent case series. These may contribute in limiting the more widespread acceptance of unicompartmental knee replacement.The aim of this paper is to review the up-to-date evidence on UKR and discuss the most relevant controversies regarding this procedure.     

Medial knee osteophytes have little influence on the medial collateral laxity during total knee replacement

Introduction  To get balanced ligaments is generally accepted as a relevant prognostic factor after total knee replacement (TKR). The exact influence of the medial osteophytes on the medial collateral laxity has never been investigated. We hypothesized that the resection of the medial femoral and tibial osteophytes would increase the medial laxity during TKR. Materials and methods  We studied 20 cases of varus gonarthrosis operated on for TKR under navigation control. Medial laxity before and after osteophyte resection were measured with the navigation system. The thickness of the resected osteophytes from the femur and the tibia was measured by comparing the pre-operative and post-operative coronal plain X-rays. Medial laxity before and after osteophyte resection were compared with a Spearman test at a 0.05 level of significance. Correlation between the difference in medial laxity and the thickness of the resected osteophytes was studied with the calculation of the Spearman correlation test at a 0.05 level of significance. Results  The mean paired difference between pre-resection and post-resection laxity was 0.5° ± 1.0°; this difference was statistically significant but of little clinical relevance. There was no difference between pre- and post-resection medial laxity by 10 patients, a 1° difference in 9 patients, and a 2° difference in one patient. There was no correlation between the thickness of the resected osteophytes (femur, tibia and total) and the difference between pre- and post-resection medial laxity. Conclusion  We demonstrated that the medial osteophytes had no clinically significant influence on the medial laxity during TKR. There is no need for routine medial osteophytes resection only for the purpose of ligamentous balancing during TKR.     

Effect of body mass index on functional outcome in primary total knee arthroplasty——a single institution analysis of 2180 primary total knee replacements

AIM To evaluate the effect of body mass index(BMI) on short-term functional outcome and complications in primary total knee arthroplasty. METHODS All patients undergoing primary total knee arthroplasty at a single institution between 2007 and 2013 were identified from a prospective arthroplasty database. 2180 patients were included in the study. Age, gender, BMI, pre- and post-operative functional scores [Western Ontario and Mc Master University Arthritis Index(WOMAC) and SF-36], complications and revision rate were recorded. Patients were grouped according to the WHO BMI classification. The functional outcome of the normal weight cohort(BMI 25) was compared to the overweight and obese(BMI ≥ 25) cohort. A separate sub-group analysis was performed comparing all five WHO BMI groups; Normal weight, overweight, class 1 obese, class 2 obese and class 3 obese.RESULTS With a mean age of 67.89(28-92), 2180 primary total knee replacements were included. 64.36%(1403) were female. The mean BMI was 31.86(18-52). Ninty-three percent of patients were either overweight or obese. Mean follow-up 19.33 mo(6-60 mo). There was no significant difference in pre or post-operative WOMAC score in the normal weight(BMI 25) cohort compared to patients with a BMI ≥ 25(P 0.05). Sub-group analysis revealed significantly worse WOMAC scores in class 2 obese 30.80 compared to overweight 25.80(P 0.01) and class 1 obese 25.50(P 0.01). Similarly, there were significantly worse SF-36 scores in class 2 obese 58.16 compared to overweight 63.93(P 0.01) and class 1 obese 63.65(P 0.01) There were 32(1.47%) superficial infections, 9(0.41%) deep infections and 19(0.87%) revisions overall with no complications or revisions in the normal weight cohort(BMI 25).CONCLUSION Post-operative functional outcome was not influenced by BMI comparing normal weight individuals with BMI 25. Patients should not be denied total knee arthroplasty based solely on weight alone.     

Preoperative knee stiffness and total knee arthroplasty outcomes

A retrospective case-control study was conducted to evaluate 1-year total knee arthroplasty (TKA) outcomes among preoperative stiff knees, range of motion (ROM) 80° or less, compared with nonstiff preoperative knees, ROM 100° or greater. A total of 134 stiff knee cases were compared with a matched cohort of 134 non-stiff knee controls. Knee Society Score and Oxford Knee Score change scores from baseline to 1 year were similar between the groups. Stiff knees experienced a significantly greater mean improvement in ROM from baseline to 1 year (30.8° ± 18.8°) as compared with nonstiff knees (1.1° ± 12.8°) (P < .0001). Although ultimate ROM of a TKA can be restricted secondary to preoperative stiffness, improvements in outcomes and ROM are not affected. We conclude that progression of stiffness should not in and of itself lead to earlier intervention of TKA in most cases.     

Regional five-year clinical outcomes of 289 consecutive cementless oxford uni-compartmental knee replacements at a non-inventor centre

IntroductionUncemented unicompartmental knee replacement offers a minimally invasive approach, faster rehabilitation and good levels of function, supported by evidence reporting low intra-operative fracture rate and mid-term stability with no implant migration at 5-years. Our aim was to examine the clinical outcomes in 289 consecutive Oxford unicompartmental knee arthroplasties (257 patients), five years post-operatively.MethodsA retrospective study of patients treated between 2008 and 2014 in a non-inventor centre by a single surgeon was performed. Patients with anteromedial bone on bone uni-compartmental arthritis were included. Oxford Knee Scores (OKSs) at last follow-up were recorded, intra-operative complications reported with commentary on revision cases.ResultsMean age of patients was 66 years (SD 9.6, 45–88 years). 122 (42%) patients were female and 135 (58%) were male. Patient in our study were ASA 1 (36%), ASA 2 (62%) and ASA 3 (01%). There were no intra-operative complications, particularly tibia fractures during impaction. The average oxford knee score was 40.1 (n = 232, Range 06 to 48, SD 8.46) at an average 6 years and 3 months from surgery, including revised patients. Six patients had their prosthesis revised within five-years of the index surgery. Five-year cumulative implant survival rate was 97.8% (95% CI 97.62 to 97.98, SE 0.09). Indications for revision were: lateral side wear (n = 1); dislocated spacer (n = 4); instability and spacer subluxation (n = 1). Thirteen patients died within five years of surgery Five-year cumulative survival rate was 94.9% (95% CI 94.87 to 94.925, SE 0.013).ConclusionThe proportion of patients requiring revision at five-years is lower than that generally reported for UKR. These findings add support for the use of the cementless oxford UKR outside the design centre.     

膝关节置换时股骨髓内定位对假体排列的影响

目的 :探讨膝关节置换时股骨髓内定位杆进针点的位置对下肢力线造成的误差及其相关的影响殷素。方法 :选取行TACK膝关节置换的骨关节病患者 40例。术中股骨截骨髓内定位杆的进针点为股骨滑车中心。术前术后于 14英寸× 17英寸X线片测量膝关节的股胫角 (FTA)、股骨外侧角。并根据数学模型计算TACK置换后可能造成的最大误差。结果 :股骨解剖轴线一般与股骨内侧髁相交 ,距滑车中心平均 7mm ( 0～ 11mm) ,膝外翻者股骨解剖轴线偏离滑车中心更多。术后测量股骨假体外侧角为 80～ 90° ,内外翻误差 2°以内者占 70 % ,理论计算如果进针点位于滑车中心 ,会导致外翻误差增加。结论 :真正的髓内定位杆进针点应位于股骨解剖轴线上 ,进针点外移会导致股骨假体过度外翻。术前应在全长或 14英寸× 17英寸站立正位X线画出股骨解剖轴线 ,根据股骨轴线与股骨髁交点的实际位置进行髓内定位 ,可减小误差