Evaluation of painful total knee arthroplasty

Total knee arthroplasty MRI featuring slice-encoding for metal artifact correction: reduction of artifacts for STIR and proton density-weighted sequences

OBJECTIVE

The purpose of this article is to compare slice-encoding for metal artifact correction (SEMAC) sequences versus optimized standard MRI sequences in patients with total knee arthroplasty (TKA).

SUBJECTS AND METHODS

Forty-two patients with TKA underwent 1.5-T MRI. Sequences optimized for metal implant imaging (SEMAC) were compared with standard sequences optimized with high bandwidth for STIR and proton density (PD)-weighted images. In 29 patients, CT was available as reference standard. Signal void and insufficient fat saturation were quantified. Qualitative criteria (anatomy, distortion, blurring, and noise) were assessed on a 5-point scale (1, no artifacts; 5, severe artifacts) by two readers. Abnormal imaging findings were noted. A Student t test and a Wilcoxon signed rank test was used for statistics.

RESULTS

Signal void areas and insufficient fat saturation were smaller for the SEMAC sequences than for the optimized standard sequences (p ≤ 0.005 for all comparisons). Depiction of anatomic structures was better on STIR with SEMAC versus standard sequences optimized with high bandwidth (score range, 2.9-3.7 vs 4.2-4.9) and on PD-weighted imaging with SEMAC versus standard sequences optimized with high bandwidth (score range, 2.5-3.5 vs 3.1-3.8), which was statistically significant (p < 0.001 to p = 0.007 for different structures). Distortion and noise were lower for SEMAC than for the standard sequences (p ≤ 0.001), whereas no technique had a clear advantage for blurring. Detection of abnormal imaging findings was markedly increased for the SEMAC technique (p < 0.001) and was most pronounced for STIR images (98 and 74 findings for STIR with SEMAC for readers 1 and 2, respectively, vs 37 and 37 findings for readers 1 and 2, respectively, for STIR with standard sequences optimized with high bandwidth). Sensitivity for detection of periprosthetic osteolysis was improved for STIR with SEMAC (100% and 86% for readers 1 and 2, respectively) compared with STIR with standard sequences optimized with high bandwidth (14% and 29% for readers 1 and 2, respectively).

CONCLUSION

SEMAC sequences showed a statistically significant artifact reduction. The detection of clinically relevant findings such as periprosthetic osteolysis was markedly improved.

Increased shape and size offerings of femoral components improve fit during total knee arthroplasty

PURPOSE

Contemporary total knee arthroplasty femoral component designs offer various degrees of fit amongst the global population. The purpose of this study was to assess component fit of contemporary femoral component design families against multiple ethnicities.

METHODS

Using a multi-ethnic dataset including Caucasian, Indian, and Korean subjects, this study investigated component fit in six contemporary femoral component design families (A: Persona™, B: NexGen (®), C: Sigma (®), D: GENESIS™ II, E: Triathlon (®), F: Vanguard (®)). Component overhang/underhang was measured between the resected distal femur and its corresponding component size and compared across design families and ethnicities. The severity of overhang/underhang and propensity of downsizing due to clinically significant overhang were quantified for the overall dataset and each ethnicity.

RESULTS

In all the overhang cases, Designs A and B had significantly lower component overhang than the other designs (p < 0.02). In all the underhang cases, Designs C and E had significantly greater underhang than the other designs (p < 0.01). Component design influenced the occurrence (% bones) of component downsizing due to clinically significant overhang (>3 mm), with the highest incidence observed in Designs D (20.5%) and F (17.7%), and the lowest incidence observed in Designs A (0%) and B (0.4%). Variation in component fit was significantly impacted by designs (p < 0.01) but not ethnicities (n.s.).

CONCLUSIONS

The inclusion of multiple ML/AP shape offerings and the increased number of available sizes in Design A, as compared to other contemporary femoral component design families studied, result in improved femoral component fit across various ethnicities.

Multidisciplinary treatment in patients with persistent pain following total hip and knee arthroplasty

In a retrospective study, we evaluated the clinical outcome of multidisciplinary pain therapy (MPT) in a consecutive series of 40 patients with persistent unexplained pain following THA or TKA. Pain intensity, physical capability and psychological status were assessed before MPT (t1), after 3 weeks (t2) and at a mean follow-up of 32 months (t3). At t2, all scores demonstrated a significant improvement compared to the baseline value. At t3, pain intensity, physical capability, and depression levels deteriorated slightly but were still significantly better compared to baseline values. Anxiety scores deteriorated between t2 and t3 and showed no difference in the baseline value. The present study suggests that MPT has beneficial short-term and mid-term effects in this subgroup of patients and may avoid exploratory revision surgery.

Anatomic tibial component design can increase tibial coverage and rotational alignment accuracy: a comparison of six contemporary designs

PURPOSE

The aim of this study was to comprehensively evaluate contemporary tibial component designs against global tibial anatomy. We hypothesized that anatomically designed tibial components offer increased morphological fit to the resected proximal tibia with increased alignment accuracy compared to symmetric and asymmetric designs.

METHODS

Using a multi-ethnic bone dataset, six contemporary tibial component designs were investigated, including anatomic, asymmetric, and symmetric design types. Investigations included (1) measurement of component conformity to the resected tibia using a comprehensive set of size and shape metrics; (2) assessment of component coverage on the resected tibia while ensuring clinically acceptable levels of rotation and overhang; and (3) evaluation of the incidence and severity of component downsizing due to adherence to rotational alignment and overhang requirements, and the associated compromise in tibial coverage. Differences in coverage were statistically compared across designs and ethnicities, as well as between placements with or without enforcement of proper rotational alignment.

RESULTS

Compared to non-anatomic designs investigated, the anatomic design exhibited better conformity to resected tibial morphology in size and shape, higher tibial coverage (92% compared to 85-87%), more cortical support (posteromedial region), lower incidence of downsizing (3% compared to 39-60%), and less compromise of tibial coverage (0.5% compared to 4-6%) when enforcing proper rotational alignment.

CONCLUSIONS

The anatomic design demonstrated meaningful increase in tibial coverage with accurate rotational alignment compared to symmetric and asymmetric designs, suggesting its potential for less intra-operative compromises and improved performance.

LEVEL OF EVIDENCE

III.

Association between long-term quadriceps weakness and early walking muscle co-contraction after total knee arthroplasty

INTRODUCTION

Quadriceps weakness is one of the primary post-operative impairments that persist long term for patients after total knee arthroplasty (TKA). We hypothesized that early gait muscle recruitment patterns of the quadriceps and hamstrings with diminished knee performance at 3months after surgery would be related to long-term quadriceps strength at 1year after TKA.

METHODS

Twenty-one subjects who underwent primary unilateral TKA and 14 age-matched healthy controls were analyzed. At 3months after TKA, the maximum voluntary isometric contraction of the quadriceps and a comprehensive gait analysis were performed. Quadriceps strength was assessed again at 1year after surgery.

RESULTS

Quadriceps muscle recruitment of the operated limb was greater than the non-operated limb during the loading response of gait (p=0.03), but there were no significant differences in hamstring recruitment or co-contraction between limbs (p>0.05). There were significant differences in quadriceps muscle recruitment during gait between the non-operated limbs of the TKA group and the healthy control group (p<0.05). The TKA group showed a significant inverse relationship between one year quadriceps strength and co-contraction (r=-0.543) and hamstring muscle recruitment (r=-0.480) during loading response at 3months after TKA.

CONCLUSIONS

The results revealed a reverse relationship where stronger patients tended to demonstrate lower quadriceps recruitment at 3months post-surgery that was not observed in the healthy peer group. The altered neuromuscular patterns of the quadriceps and hamstrings during gait may influence chronic quadriceps strength in individuals after TKA.

LEVEL OF EVIDENCE

III.

Comprehensive assessment of tibial plateau morphology in total knee arthroplasty: Influence of shape and size on anthropometric variability

Better understanding of proximal tibia morphology can lead to improvements in total knee arthroplasty (TKA) through development of tibial tray families that adequately reflect the diversity of global anatomy using an appropriate number of components. We quantified variations in proximal tibial morphology at the TKA level and characterized differences attributable to gender and ethnicity. Virtual TKA was performed on digital models of 347 tibiae, spanning both genders and multiple ethnicities. The geometry of the resection profile was quantified using both a comprehensive set of morphological measurements (reflecting size and shape) and principal component analysis (PCA). The dominant statistical modes of variation were associated primarily with size (plateau dimensions, radii, and area), with lesser contributions associated with asymmetry and aspect ratios. Medial and lateral AP dimensions were strongly correlated with plateau ML width, with minimal differences in correlations due to gender or ethnicity. In conclusion, clinically relevant differences in proximal tibia morphology at the level of TKA resections across genders and multiple ethnicities can be attributed largely to variations in overall proximal tibial size, not gender- or ethnic-specific shape variations.

Influence of landmark and surgical variability on virtual assessment of total knee arthroplasty

Given advances in recent years in imaging modalities and computational hardware/software, virtual analyses are increasingly valuable and practical for evaluating total knee arthroplasty (TKA). However, the influence of variabilities at each step in computational analyses on predictions of TKA performance for a population has not yet been thoroughly investigated, nor the relationship between these variabilities and expected variations in surgical practice. Understanding these influences is nevertheless essential for ensuring the clinical relevance of theoretical predictions. Here, a morphological analysis of proximal tibial resections within TKA is proposed and investigated. The goals of this analysis are to quantify the influence of variability in landmark detection on resection parameters and to evaluate this sensitivity relative to expected clinical variability in TKA resections. Results here are directly applicable to population-level computational analyses of morphological and functional TKA performance.

The correctness of fit of current total knee prostheses compared with intra-operative anthropometric measurements in Korean knees

We aimed to obtain anthropometric data on Korean knees and to compare these with data on commonly available total knee arthroplasties (TKAs). The dimensions of the femora and tibiae of 1168 knees were measured intra-operatively. The femoral components were found to show a tendency toward mediolateral (ML) under-coverage in small femurs and ML overhang in the large femurs. The ML under-coverage was most prominent for the small prostheses. The ML/anteroposterior (ML/AP) ratio of Korean tibiae was greater than that of tibial components. This study shows that, for different reasons, current TKAs do not provide a reasonable fit for small or large Korean knees, and that the 'gender-specific' and 'stature-specific' components help for large Korean femurs but offer less satisfactory fits for small femurs. Specific modifications of prostheses are needed for Asian knees.

Causes of a painful total knee arthroplasty. Are patients still receiving total knee arthroplasty for extrinsic pathologies?

PURPOSE

Whilst patients undergoing total knee replacements generally have good relief of their symptoms, up to 20% complain of persisting pain. Revision rates have therefore been rising, particularly so for unexplained pain. We reviewed the causes of painful total knee replacements including extrinsic causes.

METHODS

Forty-five consecutive patients referred to our department with painful total knee replacement were reviewed with our standard protocol, including history and examination, inflammatory markers and radiological studies including radiographs of the hip and knee and computed tomography scan of the knee joint.

RESULTS

Of the 45 patients, 15 patients had degenerative hip and lumbar spine disease which resolved after injections of the relevant joints. Nine patients had unexplained pain.

CONCLUSIONS

Patients may still be undergoing knee arthroplasty for degenerative lumbar spine and hip osteoarthritis. We suggest heightened awareness at pre- and post-operative assessment and thorough history and examination with the use of diagnostic injections to identify the cause of pain if there is doubt.

Causes of failure and etiology of painful primary total knee arthroplasty

The review provides an overview of the causes of failure and the many different aetiologies of a painful primary total knee arthroplasty (TKA). They can be classified into extra- and intraarticular disorders, the latter being divided into biological and mechanical origins. Whereas biological aetiologies like infections have remained stable over time, other causes of failure have changed. In the early times of knee arthroplasty, they were mainly related to technical insufficiencies. A better understanding of knee arthroplasty, patients' increasing functional demands as well as a continuous development of TKA techniques generated newer problems, which are increasingly related to the functioning of the soft-tissue envelope of the knee. From a therapeutic point of view, three situations can be considered: functional problems not needing reoperations, causes of reoperations not needing an exchange of prosthetic components as well as reoperations with exchange of at least one prosthetic component.

The value of magnetic resonance imaging in investigating a painful total knee arthroplasty

This case describes a rare cause of pain around a total knee arthroplasty and highlights the importance of a structured approach to the investigation of these patients. Magnetic resonance imaging provided detailed information about the cause of pain despite the presence of a prosthetic joint, and the pathology, primary non-Hodgkin lymphoma, was treated without the need for further surgical intervention.

The painful knee after TKA: a diagnostic algorithm for failure analysis

Pain after total knee arthroplasty (TKA) represents a common observation in about 20% of the patients after surgery. Some of these painful knees require early revision surgery within 5 years. Obvious causes of failure might be identified with clinical examinations and standard radiographs only, whereas the unexplained painful TKA still remains a challenge for the surgeon. It is generally accepted that a clear understanding of the failure mechanism in each case is required prior considering revision surgery. A practical 10-step diagnostic algorithm is described for failure analysis in more detail. The evaluation of a painful TKA includes an extended history, analysis of the type of pain, psychological exploration, thorough clinical examination including spine, hip and ankle, laboratory tests, joint aspiration and test infiltration, radiographic analysis and special imaging techniques. It is also important to enquire about the length and type of conservative therapy. Using this diagnostic algorithm, a sufficient failure analysis is possible in almost all patients with painful TKA.

The position and orientation of total knee replacement components: a comparison of conventional radiographs, transverse 2D-CT slices and 3D-CT reconstruction

We studied the intra- and interobserver reliability of measurements of the position of the components after total knee replacement (TKR) using a combination of radiographs and axial two-dimensional (2D) and three-dimensional (3D) reconstructed CT images to identify which method is best for this purpose. A total of 30 knees after primary TKR were assessed by two independent observers (an orthopaedic surgeon and a radiologist) using radiographs and CT scans. Plain radiographs were highly reliable at measuring the tibial slope, but showed wide variability for all other measurements; 2D-CT also showed wide variability. 3D-CT was highly reliable, even when measuring rotation of the femoral components, and significantly better than 2D-CT. Interobserver variability in the measurements on radiographs were good (intraclass correlation coefficient (ICC) 0.65 to 0.82), but rotational measurements on 2D-CT were poor (ICC 0.29). On 3D-CT they were near perfect (ICC 0.89 to 0.99), and significantly more reliable than 2D-CT (p < 0.001). 3D-reconstructed images are sufficiently reliable to enable reporting of the position and orientation of the components. Rotational measurements in particular should be performed on 3D-reconstructed CT images. When faced with a poorly functioning TKR with concerns over component positioning, we recommend 3D-CT as the investigation of choice.

Catastrophic polyethylene failure diagnosed with magnetic resonance imaging in a painful total knee arthroplasty

Determining the etiology of a painful knee after arthroplasty can be extremely challenging. Traditionally, orthopedists relied mainly on physical examination, laboratory results, serial radiographs, and 3-phase bone or indium-labeled white blood cell scans; however, recent advances in magnetic resonance imaging (MRI) software have given orthopedists another powerful tool in their diagnostic armamentarium. We provide the MRI software modification technique for metallic artifact reduction as well as present a novel case in which MRI was used to diagnose catastrophic polyethylene postfailure in a posterior cruciate ligament substituting knee. Although the role for MRI in the postarthroplasty knee has yet to be clearly defined, its utility in working up a painful arthroplasty when history, physical examination, and other diagnostic utilities fail to provide answers is clearly demonstrated in this case.

Clinical value of SPECT/CT for evaluation of patients with painful knees after total knee arthroplasty--a new dimension of diagnostics?

BACKGROUND

The purpose of our study was to evaluate the clinical value of hybrid SPECT/CT for the assessment of patients with painful total knee arthroplasty (TKA).

METHODS

Twenty-three painful knees in patients following primary TKA were assessed using Tc-99m-HDP-SPECT/CT. Rotational, sagittal and coronal position of the TKA was assessed on 3D-CT reconstructions. The level of the SPECT-tracer uptake (0-10) and its anatomical distribution was mapped using a validated localization scheme. Univariate analysis (Wilcoxon-Mann-Whitney, Spearmean's-rho test, p < 0.05) was performed to identify any correlations between component position, tracer uptake and diagnosis.

RESULTS

SPECT/CT imaging changed the suspected diagnosis and the proposed treatment in 19/23 (83%) knees. Progression of patellofemoral OA (n = 11), loosening of the tibial (n = 3) and loosening of the femoral component (n = 2) were identified as the leading causes of pain after TKA.Patients with externally rotated tibial trays showed higher tracer uptake in the medial patellar facet (p = 0.049) and in the femur (p = 0.051). Patients with knee pain due to patellofemoral OA showed significantly higher tracer uptake in the patella than others (p < 0.001).

CONCLUSIONS

SPECT/CT was very helpful in establishing the diagnosis and guiding subsequent management in patients with painful knees after TKA, particularly in patients with patellofemoral problems and malpositioned or loose TKA.

Kinematics of medial osteoarthritic knees before and after posterior cruciate ligament retaining total knee arthroplasty

Total knee arthroplasty (TKA) is a widely accepted surgical procedure for the treatment of patients with end-stage osteoarthritis (OA). However, the function of the knee is not always fully recovered after TKA. We used a dual fluoroscopic imaging system to evaluate the in vivo kinematics of the knee with medial compartment OA before and after a posterior cruciate ligament-retaining TKA (PCR-TKA) during weight-bearing knee flexion, and compared the results to those of normal knees. The OA knees displayed similar internal/external tibial rotation to normal knees. However, the OA knees had less overall posterior femoral translation relative to the tibia between 0° and 105° flexion and more varus knee rotation between 0° and 45° flexion, than in the normal knees. Additionally, in the OA knees the femur was located more medially than in the normal knees, particularly between 30° and 60° flexion. After PCR-TKA, the knee kinematics were not restored to normal. The overall internal tibial rotation and posterior femoral translation between 0° and 105° knee flexion were dramatically reduced. Additionally, PCR-TKA introduced an abnormal anterior femoral translation during early knee flexion, and the femur was located lateral to the tibia throughout weight-bearing flexion. The data help understand the biomechanical functions of the knee with medial compartment OA before and after contemporary PCR-TKA. They may also be useful for improvement of future prostheses designs and surgical techniques in treatment of knees with end-stage OA.

Internal rotational error of the tibial component is a major cause of pain after total knee replacement

This study used CT analysis to determine the rotational alignment of 39 painful and 26 painless fixed-bearing total knee replacements (TKRs) from a cohort of 740 NexGen Legacy posterior-stabilised and cruciate-retaining prostheses implanted between May 1996 and August 2003. The mean rotation of the tibial component was 4.3 degrees of internal rotation (25.4 degrees internal to 13.9 degrees external rotation) in the painful group and 2.2 degrees of external rotation (8.5 degrees internal to 18.2 degrees external rotation) in the painfree group (p = 0.024). In the painful group 17 tibial components were internally rotated more than 9 degrees compared with none in the painfree group (p < 0.001). Additionally, six femoral components in the painful group were internally rotated more than 6 degrees compared with none in the painfree group (p = 0.017). External rotational errors were not found to be associated with pain. Overall, 22 (56.4%) of the painful TKRs had internal rotational errors involving the femoral, the tibial or both components. It is estimated that at least 4.6% of all our TKRs have been implanted with significant internal rotational errors.

Comparison of pain perception between open and minimally invasive surgery in total knee arthroplasty

Total knee arthroplasty (TKA) was a well-established procedure that had shown excellent long-term results in terms of reduced pain and increased mobility. Pain was one of the most important outcome measures that contributed to patient dissatisfaction after TKA. After a computerized search of the Medline and Embase databases, we considered articles from January 1st, 1997 to October 31st, 2009 that underlined the impact on patient pain perception of either standard open total knee arthroplasty or minimally invasive total knee arthroplasty. We included articles that used the visual analog scale (VAS), Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC), Knee Score, Hospital for Special Surgery Score (HSS), Oxford Knee Score (OKS) as postoperative pain indicators, and we included studies with a minimum follow-up period of two months. We excluded studies that monitored only functional postoperative knee activities. It was shown that TKA with the open technique was a better treatment for knees with a positive effect on pain and function than the minimally invasive technique.

Arthroscopic treatment of patellar clunk and synovial hyperplasia after total knee arthroplasty

Patellofemoral pain, crepitus, and locking are infrequent symptoms after total knee arthroplasty (TKA). We performed a retrospective review of 25 patients who underwent arthroscopic debridement after primary TKA to treat the patellar clunk syndrome (15 knees) or patellofemoral synovial hyperplasia (10 knees). After surgery, patient-reported knee pain and crepitus as well as Knee Society knee and function scores improved in both groups. Postoperative knee range of motion remained unchanged. Arthroscopic debridement of symptomatic patellofemoral synovium after TKA is a safe and effective procedure.

Determining "true" leukocytosis in bloody joint aspiration

This study intends to determine the diagnostic value of implementing a corrective formula that can adjust for serum leukocytes in bloody joint fluid. Our cohort included 91 infected and 37 aseptic total knee arthroplasties. Joint fluid leukocyte count (>1760/microL) and neutrophil percentage (>73%) were the cutoff values for deep infection. The adjusted fluid leukocyte counts were calculated using the following simple formula: WBCadjusted=WBCobserved-[(WBCblood x RBCfluid/RBCblood)]predicted. Adjusted fluid cell counts of only 5 infected patients dropped below the cutoff value, whereas the remaining 86 maintained a high cell count. Ten noninfected patients had false-positive cell counts, 6 of which were successfully corrected to levels below the designated thresholds. The aspirates that were corrected had a greater number of introduced white blood cells. This study suggests that our corrective formula can detect false-positive joint aspirations without jeopardizing the diagnosis of periprosthetic infection.

Postoperative Imaging of the Knee

The knee is a frequently injured joint and, thus, a common focus of operative intervention. As operative techniques and imaging modalities evolve, radiologists must be aware of the expected postoperative appearance after knee surgeries that are performed commonly and also must be comfortable recognizing complications encountered commonly in the immediate and delayed postoperative period. Drawing on the large amount of attention this subject has received of late in the radiologic and orthopedic literature, this article reviews the knee surgeries performed most commonly and the expected normal and most frequently encountered abnormal postoperative imaging findings with an emphasis on MR imaging.

Postarthroplasty ???Palsy??? and Systemic Neuropathy

Postarthroplasty palsy, occurrence of dysfunction of the sciatic or peroneal nerve after total joint replacement of the hip or knee, is a complication that remains poorly understood. Characteristics of a series of 24 patients with postarthroplasty palsy are reviewed, with the finding that, overall, 58.4% of the patients had an underlying peripheral neuropathy. The role of this neuropathy predisposing the arthroplasty patient to stretch/traction injury is discussed and should be emphasized as a risk factor prior to surgery and should influence the surgeon's intraoperative use of force during the arthroplasty procedure. This clinical problem is addressed from the perspective of peripheral nerve surgery, with an algorithm suggested for its management. The algorithm suggests that if a peroneal palsy is still present at 3 months after an arthroplasty and neurosensory testing fails to demonstrate a sensory reinnervation pattern in the territories of the deep or superficial peroneal nerve, then surgical neurolysis of the common peroneal nerve is indicated.

Bilateral simultaneous extensor mechanism disruption following simultaneous bilateral total knee replacement

Extensor disruptions of the knee following the total knee replacements are uncommon. We describe a case of postoperative bilateral simultaneous extensor mechanism disruption following simultaneous bilateral total knee replacement. On both sides, the patient sustained open wounds. The extensor mechanism was successfully repaired on both sides, but the outcome is less than satisfactory.

Imaging of knee arthroplasty

Knee replacement surgery, either with unicompartmental or total systems, is common. The purpose of this manuscript is to review the appearance of normal knee arthroplasty and the appearances of complications such as infection, polyethylene wear, aseptic loosening and particle-induced osteolysis, patellofemoral abnormalities, axial instability, and periprosthetic and component fracture. Knowledge of the potential complications and their imaging appearances will help the radiologist in the diagnostic evaluation of the patient with a painful knee arthroplasty.

Comparison of subtraction arthrography, radionuclide arthrography and conventional plain radiography to assess loosening of total knee arthroplasty / Vergleich von Subtraktionsarthrographie, Radionuklidarthrographie und konventionellem Röntgen zur Erfassung von Prothesenlockerungen in der Knierevisionschirurgie

The value of plain radiographs, digital subtraction arthrography and radionuclide arthrography was analysed in 23 cases of failed total knee arthroplasty. The preoperative diagnosis was compared with the intraoperative assessment. Sensitivity, specificity and the positive and negative predictive value for assessing a loose component were determined separately for the femoral and tibial components. At revision we found 13 loose femoral and 12 loose tibial implants. In eight cases both components were unstable. Plain radiography had a sensitivity of 77% for loosening of the femoral and 83% for the tibial component; digital subtraction arthrography 77% for the femoral and 8% for the tibial component and radionuclide arthrography 31% and 8%. The specificity for plain radiography was 90% for the femoral and 72% for the tibial implant. For subtraction arthrography it was 50% and 82% and for subtraction arthrography 70% and 82%. Radiography had the highest positive and negative predictive values for both components compared with the other two techniques. As a diagnostic tool to detect implant loosening, plain radiography is the most effective in this study. Subtraction arthrography and radionuclide arthrography are not suitable for use as routine methods for detection of total knee arthroplasty loosening.