Mechanisms of failure in total knee arthroplasty

The major mechanisms of failure in total knee arthroplasty are loosening, instability, sepsis, extensor mechanism power loss, poor range of motion, bone fractures, and prosthesis fracture. These are, for the most part, within the surgeon's control. Prosthetic alignment is the most important factor influencing postoperative loosening and instability.     

Early mechanical failure in total knee arthroplasty

Early mechanical dysfunction of a total knee arthroplasty (TKA) is a challenging problem in terms of causality and solutions. The current strategy in our department is to perform a complete TKA revision rather than the less invasive partial procedures when a clear mechanical cause of failure has been found. In this investigation, we assessed 21 patients who underwent complete TKA revision in 2003-2004 in our institution within the first two years following the index TKA. Various clinical presentations included pain, stiffness, instability, and femoro-patellar signs. These corresponded to implant size, position, and fixation issues. The IKS knee score/function significantly increased from 47/47 to 85/78 at follow-up (six months minimum). Compared to the data in the literature, this systematic full revision seems to be a reasonable approach. This attitude takes advantage of the modularity of the implants for allowing perioperative adjustments of position, fixation, and constraint. Based on the results of our study, we propose a list of six mechanical pitfalls to be evaluated in the case of early dysfunction: frontal misalignment, sagittal overstuffing or malpositioning, axial malrotation, poor bone fixation, inappropriate constraint or ligamentous balance, and inappropriate level of the joint space.     

Prodromes of failure in total knee arthroplasty.

A total of 102 revision total knee arthroplasties (TKAs) were reviewed to determine the prodromal symptoms and radiographic findings associated with failure. Presenting symptoms included pain (84%); swelling (76%); progressive varus or valgus deformity (19%); instability (17%); stiffness (17%); clicking or grinding (7%); catching (4%); and patellar pain, subluxation, or clicking (4%). Radiographs were diagnostic in 91% of cases, demonstrating complete radiolucencies (80%), polyethylene wear (43%), component breakage (5%), metallic debris (3%), patellar subluxation or dislocation (4%), and osteolysis (4%). Gross intraoperative findings included polyethylene wear (72%), osteolysis (22%), metal-wear synovitis (9%), component breakage (6%), patellar wear and dissociation (4%), and occult sepsis (5%). The average duration of symptoms was 13 months; the interval between orthopedic evaluations averaged 23 months. Based on this information, we recommend that an annual questionnaire and weight-bearing radiographs be used to ensure adequate surveillance of TKA patients and avoid complications associated with delay in diagnosis of polyethylene wear or implant loosening.     

Patellofemoral function in total condylar knee arthroplasty

Summary A series of 100 total condylar knee arthroplasties was studied to determine radiographic and clinical patellofemoral function. Before operation there was lateral patellar tilt in 31 cases and lateral displacement in 52. After operation tilt was present in 8 and displacement in 14. Only a few patients had medial patellar displacement. Dislocation or fracture of the patella was not encountered. Six patients had postoperative patellar pain. In one case there was a radiolucent zone at the bone-cement interface in the patella, without pain. Patellofemoral function before operation was good in 3, fair in 54, and poor in 43 cases. After operation it was good in 88 and fair in 12. Both tilt and displacement slightly reduced postoperative patellofemoral function. Patellar reconstruction with the total condylar prothesis shows reasonably good tolerance of moderate malpositioning of the patellar prosthesis, affords sufficient stability and usually painless patellofemoral function.

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Résumé Les auteurs ont étudié une série de 100 arthroplasties du genou de type »total condylar« afin d'apprécier cliniquement et radiologiquement la fonction fémoro-patellaire. Avant l'opération il existait une bascule externe de la rotule dans 31 cas et une subluxation externe dans 52. Après l'opération, la bascule a été retrouvée 8 fois et la subluxation 14 fois. Quelques malades seulement présentaient une subluxation interne. Il n'y avait ni luxation ni fracture de la rotule. Six opérés se plaignaient de douleurs rotuliennes. Dans un cas on notait sur la radiographie une zone claire entre l'os et le ciment, mais sans douleur. La fonction fémoro-patellaire avant l'opération était bonne dans 3 cas, passable dans 54 et mauvaise dans 43. Après l'opération, elle était bonne 88 fois et passable 12 fois. Aussi bien la bascule que la subluxation réduisent un peu la fonction post-opératoire de l'articulation fémoropatellaire. La reconstruction de la rotule lors de l'arthroplastie »total condylar« tolère une légère malposition de la prothèse rotulienne, assure une stabilité suffisante et, habituellement, une fonction indolore.

     

Revision total knee arthroplasty for aseptic failure

Twenty-four patients with 28 failed total knee arthroplasties replaced with porous-coated anatomic (PCA) primary or revision components were studied over a two- to four-year period. Overall, there were 68% good and excellent results and three failures. When evaluated according to mode of failure, 83% of the patients who had a definable mechanical problem achieved good or excellent results. Patients who had revision operations for incapacitating pain or in whom no clearly definable problem could be ascertained before operation were not significantly improved. Complications that led to poor results were deep sepsis, wound necrosis, and extensor mechanism abnormalities.     

Patellar component failure in cementless total knee arthroplasty

One hundred twenty-two total knee arthroplasties were performed with porous ingrowth fixation of the patellar component between February 1984 and February 1987. Twelve subsequently have experienced fatigue fracture of the patellar component at the peg-plate junction. All fractured patellar components demonstrated excellent ingrowth and fixation of the porous titanium fiber mesh-peg surfaces with no ingrowth into the porous plate underlying the polyethylene patellar surface. While the initial group of 122 arthroplasties was only slightly greater than one-third male, the preponderance of patellar fractures was in males (ten of 12). Patients with patellar component failure were on average younger and heavier and had a greater range of knee motion than the index group. The average time from implantation to recognition of fracture was 24 months. Biomechanical analysis of the force system about a domed patella demonstrated that loading of the patellofemoral joint results in eccentric loading of the dome surface. Peg fixation not accompanied by fixation of the overlying plate allows these high eccentric forces to load the peg-plate junction in shear with consequent fatigue at the peg-plate junction. These results indicate that the shear forces are sufficiently high to warrant caution in the use of peg-plate systems in which peg ingrowth without plate ingrowth occurs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tibial component failure mechanisms in total knee arthroplasty

The purpose of this study was to examine the failure mechanisms and factors associated with failure of a nonmodular metal backed cemented tibial component. Out of 3152 total knee replacements done for osteoarthritis, 41 tibial components had been revised (1.3%). Four distinct failure mechanisms were identified: 20 knees were revised for medial bone collapse, 13 for ligamentous imbalance, 6 for progressive radiolucencies, and 2 for pain. Factors associated with medial bone collapse were varus tibial component alignment more than 3.0 degrees , Body Mass Index higher than 33.7, and overall postoperative varus limb alignment. Ligamentous imbalance was more prevalent in knees with preoperative valgus deformity. There were no knees revised for tibial component polyethylene wear or osteolysis. We conclude that the dominant failure mechanisms for this component design are related to preoperative deformity, technical factors of component alignment, overall limb alignment, and ligamentous imbalance.     

Gross polyethylene failure in total knee arthroplasty.

A total of 12 total knee replacements in nine patients with evidence of gross polyethylene failure at the time of revision surgery were identified. There were nine tibial and three patellar component failures. The average time from index to revision arthroplasty was 6 years (range: 0.75 to 9.63). A retrospective cohort group was identified based on date of operation. The average patient weight of the initial group was 89.6 kg (range: 76 to 104 kg), compared with 74.8 kg (range: 47 to 108 kg) (P = .045) in the control group. There was a male sex preponderance in the failure group (P = .045). The average height of the study group was 176 cm, compared to 161 cm for the control group (P = .003). Using the modified OASDI scale, the failure group had a higher activity level (P = .023). Pre-revision limb alignment in patients with failed TKA was statistically different from controls and served as an indication of polyethylene failure (P = .04). The selection of modular prosthetic component systems that allow for easy polyethylene revision is indicated in the high risk patient group identified. Close follow up is needed to minimize the sequela of polyethylene failure.     

The effect of obesity on quality-of-life improvement after total knee arthroplasty

Obesity has been consistently implicated as a major risk factor in the development and progression of osteoarthritis (OA), and total joint arthroplasty (TJA) has emerged as one of the most efficacious and cost-effective OA treatments. The effectiveness of this treatment manifests itself in both clinical and quality of life (QOL) measures. Given the interrelatedness of obesity and OA, and given the success of TJA in improving QOL, we conducted a study to determine whether obesity would adversely affect QOL improvement in 50 patients who underwent primary total knee arthroplasty for primary knee OA. Our results show that, 6 months after surgery, QOL measures improved more for obese patients than for overweight patients and patients with ideal body weight.     

Polyethylene post failure in posterior stabilized total knee arthroplasty

Posterior-stabilized (PS) prostheses have been used extensively in total knee arthroplasty (TKA), with excellent long-term results. The key feature of these prostheses is the femoral cam and tibial post mechanism that limits posterior displacement and produces femoral rollback. Although articular-surface polyethylene wear of the tibial component has not been a significant clinical problem, tibial post wear has been reported. In distinction to chronic post wear, little information exists about catastrophic post failure. We present the case of a 56-year-old woman who presented 63 months after TKA with a PS prosthesis with acute fracture of the polyethylene post. The evaluation and treatment of this patient, including the previously unreported use of computed tomography arthrography to diagnose this rare problem, is reviewed.     

Bone cement product and failure in total knee arthroplasty

Background and purpose — The bone cement market for total knee arthroplasty (TKA) in Norway has been dominated by a few products and distributors. Palacos with gentamicin had a market share exceeding 90% before 2005, but it was then withdrawn from the market and replaced by new slightly altered products. We have compared the survival of TKAs fixated with Palacos with gentamicin with the survival of TKAs fixated with the bone cements that took over the market.

Patients and methods — Using data from the Norwegian Arthroplasty Register for the period 1997–2013, we included 26,147 primary TKAs in the study. The inclusion criteria were TKAs fixated with the 5 most used bone cements and the 5 most common total knee prostheses for that time period. 6-year Kaplan-Meier survival probabilities were established for each cement product. The Cox proportional hazards regression model was used to assess the association between bone cement product and revision risk. Separate analyses were performed with revision for any reason and revision due to deep infection within 1 year postoperatively as endpoints. Adjustments were made for age, sex, diagnosis, and prosthesis brand.

Results — Survival was similar for the prostheses in the follow-up period, between the 5 bone cements included: Palacos with gentamicin, Refobacin Palacos R, Refobacin Bone Cement R (Refobacin BCR), Optipac Refobacin Bone Cement R (Optipac Refobacin BCR), and Palacos R?+?G.

Interpretation — According to our findings, the use of the new bone cements led to a survival rate that was as good as with the old bone cement (Palacos with gentamicin).     

The effect of obesity on quality-of-life improvement after total knee arthroplasty.

Obesity has been consistently implicated as a major risk factor in the development and progression of osteoarthritis (OA), and total joint arthroplasty (TJA) has emerged as one of the most efficacious and cost-effective OA treatments. The effectiveness of this treatment manifests itself in both clinical and quality of life (QOL) measures. Given the interrelatedness of obesity and OA, and given the success of TJA in improving QOL, we conducted a study to determine whether obesity would adversely affect QOL improvement in 50 patients who underwent primary total knee arthroplasty for primary knee OA. Our results show that, 6 months after surgery, QOL measures improved more for obese patients than for overweight patients and patients with ideal body weight.     

The kinematic total knee arthroplasty

In 86 patients 102 consecutive cemented Kinematic total knee arthroplasties were reviewed 10-15 years after surgery to determine the clinical and radiographic results and to assess the survival rate. The average age of the 65 female and 21 male patients at the time of surgery was 63 years. Forty-six knees were affected by rheumatoid arthritis (RA), 46 by osteoarthritis (OA), 7 by haemophilic arthropathy and 3 by osteonecrosis. One patient (1 knee) was lost to follow-up, and 31 patients (38 knees) died. Eleven knees had been revised for deep infection (4), wear (4), malposition (2) or persistent pain (1). Fifty-two knees were examined at an average follow-up period of 12 years. The mean Knee Society Score of 89 points was the same for RA and AO knees. Also, 92% of the knees caused no pain or only occasional mild pain. There were no cases of aseptic loosening of any component. Progressive radiolucent lines were not seen on the follow-up radiographs (43 knees, mean follow-up 12 years) The 10- and 14-year survival rates with revision as the end-point were 90% (confidence interval, CI: 81%-95%) and 82% (CI: 67%-92%), respectively. In the worst case scenario, with knees lost to follow-up and knees with moderate pain considered as failures, the 10- and 14-year survival rates were 80% (CI: 69%-88%) and 62% (CI: 46%-77%), respectively. The Kinematic total knee arthroplasty yields equally good long-term results in patients with RA and those with OA. Deep infection and wear were the main reasons for revision.     

Delayed failure of meniscal bearing elements in total knee arthroplasty

Dislocation and early fracture of meniscal bearing elements have been reported after New Jersey low-contact-stress (DePuy, Warsaw, IN) total knee arthroplasty. Delayed wear and subsequent failure of meniscal bearing elements in two cases, 8 and 9 years after surgery, are reported.     

The GSB total knee arthroplasty

From 1981 to 1987, 77 GSB-II total knee arthroplasties were implanted in 65 patients. There were 23 men and 42 women aged on average 60 years old (range 30–85 years). The diagnosis was osteoarthritis (OA) in 21 knees, rheumatoid arthritis (RA) in 44 knees, and other in 12 knees. A clinical and radiological follow-up was performed in two stages after a mean of 6.7 years (61 knees) and 14.8 years (22 knees) to assess the medium- and long-term results and to determine if deterioration had occurred after mid-term follow-up. A survival analysis was done with two endpoints: (1) revision, and (2) revision, moderate or severe pain and lost to follow-up (worst-case scenario). At the last follow-up 36 patients (44 knees) had died, 2 patients (2 knees) refused examination, and 3 patients (3 knees) were lost to follow-up. Six knees had been revised for malposition (1.3%), septic (3.9%) and aseptic (2.6%) loosening. The mean Knee Society score after 6.7 and 14.8 years was 85 points (OA 82 points, RA 87 points). Lateralisation, subluxation or dislocation of the patella was present in 8 of 17 knees at the last follow-up. The 6- and 15-year survival rates with revision as the endpoint were 95% (CI 89%–100%) and 87% (CI 65%– 100%), respectively. For the worst-case scenario, the 6- and 15-year survival rates were 95% (CI 89%–100%) and 56% (CI 0%–100%), respectively. The medium- and long-term results of the GSB-II total knee arthroplasty were good, and a decline in the knee score did not occur beyond the mid-term follow-up. Patella complications were abundant, and a marked decrease in implant survival was noted when moderate or severe pain and lost to follow-up were included as endpoints. Received: 23 August 1999     

The octogenarian total knee arthroplasty

Sixty-five patients aged > 80 years were compared to 65 patients aged between 60 and 70 years to assess total knee arthroplasty (TKA) outcome using the octogenarian postoperative Knee Society knee and function scores. Knee Society knee scores showed excellent outcomes with no statistically significant difference in the younger cohort (preoperative score, P = .7156; 5-year score, P = -.0677). Knee Society function scores also showed good outcomes with no statistically significant difference between the groups (preoperative score, P = .1147; 5-year score, P = .1348). Average length of stay increased by 3 days for octogenarians. Octogenarians had more pre-existing medical conditions and suffered more postoperative confusion. All but 1 patient rated the result as good/excellent. Patients maintained their independence for approximately 3.5 years before requiring more social input. With careful preoperative planning and counseling, TKA is recommended for the octogenarian.     

影响骨关节炎患者全膝关节置换术后关节功能的相关因素分析

[目的]探讨影响骨关节炎患者全膝关节置换术后关节功能的相关因素.[方法]对41例43膝骨关节炎终末期行全膝关节置换术(total knee arthroplasty,TKA)患者术前、术后半年的膝关节功能进行HSS评分,应用Pearson相关分析及多重线性回归对术后膝关节HSS评分与患者年龄、体重指数、疼痛评分、术前膝关节活动度(ROM)、内翻畸形程度、手术前后股骨前髁偏距(ACO)变化情况,术后胫骨平台后倾角(PSA)等因素进行统计分析;并分析手术前后股骨前髁偏距(ACO)变化情况,术后胫骨平台后倾角(PSA)与术后膝关节ROM之间的关系.[结果]Pearson相关分析结果可以看出术前疼痛评分、术前膝关节ROM、术后胫骨平台PSA、手术前后股骨ACO变化与术后膝关节功能HSS评分呈正相关;体重指数、膝内翻畸形程度与术后膝关节功能HSS评分呈负相关.逐步回归分析经筛选后纳入方程的变量只有术后胫骨平台PSA (P＜0.01)、术前疼痛功能评分(P＜0.01)、体重指数(P＜0.05),根据标准回归系数的绝对值大小排序,对应变量的作用排序为术后胫骨平台PSA (0.555)＞术前疼痛评分(0.357)＞体重指数(0.187).ACO术前大于术后组的患者术后膝关节ROM明显好于ACO术前小于术后组(P＜0.05).术后胫骨平台PSA 7°～9°组术后膝关节活动度最好.[结论](1)术前疼痛评分、术前膝关节ROM、术后胫骨平台PSA、术前术后股骨ACO变化与术后膝关节HSS评分呈正相关,体重指数、膝关节内翻畸形与术后膝关节功能HSS评分呈负相关;(2)术后胫骨平台PSA、术前疼痛评分、体重指数对术后半年膝关节HSS评分影响显著;(3)股骨ACO变化对术后膝关节活动度有影响,术后胫骨平台PSA7°～9°膝关节活动度好.     

Mobility and perceived function after total knee arthroplasty

Mobility using the timed up and go (TUG) and perceived pain, stiffness, and physical function (Western Ontario McMaster Universities Osteoarthritis Index) were documented after total knee arthroplasty (TKA). The relationships between mobility and perceived function are limited post-TKA. The first purpose of this study was to determine and compare the TUG test between individuals (n = 11) post-TKA and age-sex-related controls (n = 11). The second purpose of this study was to explore the relationships between mobility and self-reported function post-TKA. The TKA group was 28% (P < .05) slower in completing the TUG compared with controls and reported difficulty in attempting challenging tasks. The TUG was moderately related to the physical function (0.63) dimension of the Western Ontario and McMaster Universities Osteoarthritis Index, as well as the aggregate Western Ontario and McMaster Universities Osteoarthritis Index score (0.59).