Comparison of digital and plain radiography preoperative templating in total knee arthroplasty

We present the results of prospective evaluation of digital compared to plain radiographic preoperative templating for primary total knee replacement. All consecutive patients undergoing primary knee replacement were eligible. Patients with previous knee replacement or without calibrated digital or plain radiographs were excluded. Plain radiographs were templated against acetate templates. Digital images were templated with the help of commercial software TraumaCad. A 25-mm spherical metal ball placed nearest to the affected knee joint acted as calibration object. The ICC value for intra-rater reliability was 0.846 for tibial templating and 0.840 for femoral templating. PFC sigma cruciate substituting components were implanted in all patients. Twenty-eight consecutive patients between April 2006 and June 2007 were included. Accurate digital templating score was 80% for tibial implant and 40% for femur. Accuracy of analog templating was 55% for tibial implant and 50% for femur. There was no mismatch of over one size. The differences between templated and implanted sizes were plotted against their mean in Bland–Altman plot. The 95% confidence interval of the differences between digital and actual sizes were: 0.78 to −0.75 sizes for tibial implant and 1.15 to −0.93 sizes for femoral implant. The 95% confidence interval of the differences between plain and actual sizes were: 0.38 to −0.99 size for tibial implant and 0.93 to −1.32 size for femoral implant. The two tailed P value for difference between digital and analog templating from a Wilcoxon matched pair signed rank test was 0.021 for tibia and 0.006 for femur. We found preoperative templating by the operating surgeon reliable and accurate but digital templating did not offer any additional advantage.     

Evaluation of the accuracy and use of x-ray markers in digital templating for total hip arthroplasty

Despite benefits of digital templating, digital image acquisition techniques often make image magnification unknown and variable. We assessed the accuracy of digital x-ray scaling devices based on position. Radiographs of 106 total hip arthroplasty (THA) patients were studied to determine the accuracy of 2 digital x-ray markers at 1 of 4 positions by comparing true to expected x-ray magnification. The Pearson r coefficient was calculated as an indicator of measurement correlation between investigators. Greater accuracy was obtained for markers placed at the greater trochanter without skin overlap than for markers placed with soft tissue or bone overlap on x-ray. Flexible positioning markers provided greater accuracy than adhesive markers. Based on our data, we suggest positioning at the greater trochanter without skin overlap on x-ray and suggest flexible positioning over adhesive marker use.     

Digital pre-operative templating is more accurate in total hip replacement compared to analogue templating

We prospectively evaluated the accuracy of digital compared to analogue pre-operative templating in 50 consecutive primary hip replacements between April 2006 and June 2007. The senior author pre-operatively templated implant size using TraumaCad (Orthocrat Limited, Israel). Thirty-one Exeter primary hip and 19 hybrid hip replacements were performed. Hips were templated using radiographs calibrated against a spherical metal ball. For each hip, an AP pelvis view was used. Acetabular implants used were either Trident PSL or Exeter contemporary cup (Stryker). Femoral stem was Exeter (Stryker). Predicted implant sizes were documented. Post-operatively, the predicted implant size was compared to the implanted components. All post-operative films showed good fit of components and there were no intraoperative or post-operative fractures. The intra-rater reliability (ICC) of analogue templating was 0.96 and digital templating was 0.90. Accurate templating score for acetabular cup was 46% (digital) 43% (analogue), femoral offset was 80% (digital) 70% (analogue), femoral stem was 76% (digital) 60% (analogue). The differences between templating and actual implant sizes were plotted in Bland–Altman plot. Digital templating produced narrower confidence interval compared to analogue templating. Digital templating proved to be statistically, significantly more accurate compared to analogue templating for acetabluar cup and femoral stem. Our data indicate that digital templating is more reliable in predicting actual implant sizes for total hip arthroplasty when performed by the operating surgeon.     

Scaling digital radiographs for templating in total hip arthroplasty using conventional acetate templates independent of calibration markers

We describe a scaling method for templating digital radiographs using conventional acetate templates independent of template magnification without the need for a calibration marker. The mean magnification factor for the radiology department was determined (119.8%; range, 117%-123.4%). This fixed magnification factor was used to scale the radiographs by the method described. Thirty-two femoral heads on postoperative total hip arthroplasty radiographs were then measured and compared with the actual size. The mean absolute accuracy was within 0.5% of actual head size (range, 0%-3%) with a mean absolute difference of 0.16 mm (range, 0-1 mm; SD, 0.26 mm). Intraclass correlation coefficient showed excellent reliability for both interobserver and intraobserver measurements with intraclass correlation coefficient scores of 0.993 (95% CI, 0.988-0.996) for interobserver measurements and intraobserver measurements ranging between 0.990 and 0.993 (95% CI, 0.980-0.997).     

The accuracy of preoperative templating in cementless total hip arthroplasty

We evaluated the accuracy and clinical usefulness of preoperative templating in 109 cementless total hip arthroplasties. The size of the prosthesis was exactly predicted in 46 (42.2%) acetabular and 75 (68.8%) femoral components. The accuracy increased to greater than 90% if the prosthesis size was within 1 or 2 sizes (above or below) for femoral component and acetabular components, respectively. Having a contralateral total hip arthroplasty as a guide for preoperative templating was associated with greater accuracy in predicting the femoral component size only. Eighty-eight percent of the acetabular components were oriented inside the presumed safe range for inclination; 42% of the acetabular components were in the presumed safe range of anteversion. The mean postoperative leg length discrepancy was 0.9 +/- 6.8 mm; 93.5% had a discrepancy within 10 mm.     

Patient-specific instruments in total knee arthroplasty

Purpose

In recent years, patient-specific instruments (PSI) has been introduced with the aim of reducing the overall costs of the implants, minimising the size and number of instruments required, and also reducing surgery time. The purpose of this study was to perform a review of the current literature, as well as to report about our personal experience, to assess reliability of patient specific instrument system in total knee arthroplasty (TKA).

Methods

A literature review was conducted of PSI system reviewing articles related to coronal alignment, clinical knee and function scores, cost, patient satisfaction and complications.

Results

Studies have reported incidences of coronal alignment ≥3° from neutral in TKAs performed with patient-specific cutting guides ranging from 6 % to 31 %.

Conclusions

PSI seem not to be able to result in the same degree of accuracy as the CAS system, while comparing well with standard manual technique with respect to component positioning and overall lower axis, in particular in the sagittal plane. In cases in which custom-made cutting jigs were used, we recommend performing an accurate control of the alignment before and after any cuts and in any further step of the procedure, in order to avoid possible outliers.     

Digital templating in total hip arthroplasty with the Mayo stem

Patients  In 40 patients undergoing total hip arthroplasty with the Mayo femoral stem we studied how preoperative digital templating corresponded to the actual intraoperative choice of implant size, position, offset and restoration of leg length. Results  The preoperatively planned sizes of the components showed a high rate of coincidence with the sizes used intraoperatively [Intraclass Correlation Coefficient (ICC) 0.661–0.810]. However, the agreements in offset and CCD correction were poor (ICC 0.476, 0.253). This could be statistically attributed to the change in the distance from the medial margin of the stem to the medial margin of the medial femoral cortex and the height of osteotomy. The agreement in leg length correction was moderate (ICC 0.583), which was attributed to the change in the hip rotation center and the height of osteotomy. Conclusion  Careful preoperative planning was useful for accurate size choice of the Mayo prosthesis. Factors such as the height of osteotomy and the distance from the medial margin of the stem to the medial margin of the medial femoral cortex in relation to the position of the Mayo stem should be taken into account in order to restore ideal offset and leg length.     

Design and kinematics in total knee arthroplasty

Purpose

Posterior stabilised (PS) total knee arthroplasty (TKA) design development that focused on restoring normal knee kinematics was followed by the introduction of reason-guided motion designs. Although all PS fixed-bearing knee designs were thought to have similar kinematics, reports show they have differing incidences and magnitudes of posterior femoral rollback and axial rotation. In this retrospective comparative study between two guided-motion total knee systems, we hypothesised that kinematic pattern has an influence on clinical and functional outcomes.

Methods

This study represents the continuation of a previously reported clinical and kinematics analysis. We retrospectively reviewed 347 patients treated with two different TKA designs: Scorpio NRG (Stryker Orthopedics) and Journey Bi-Cruciate Stabilised (BCS) knee system (Smith & Nephew). Two hundred and eighty-one patients were assessed clinically. Patients were divided into groups according to implanted TKA. Clinical evaluation with the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire was performed. Fifteen Scorpio NRG and 16 Journey BCS patients underwent video fluoroscopy during stair climbing, chair rising/sitting and step up/down at six months of follow-up.

Results

At an average 29 months of clinical follow-up, patients with Journey BCS TKAs reported better clinical results. Stiffness was more frequently reported in the Journey group (5.2 % vs 1.2 %), whereas anterior knee pain was observed in the Scorpio NRG group (1.9 %) only. Both prosthetic models reported different posterior translation of the medial and lateral contact points (CP) in all analysed motor tasks during knee flexion (BCS 10–18 mm; NRG Scorpio 2–3 mm). Both designs produced progressive external rotation of the femoral component relative to the tibia during flexion.

Conclusions

Journey BCS showed statistically significant better KOOS results. The higher posterior femoral rollback observed in the kinematic assessment of this design, associated with a better patellofemoral design, may be the reason for better clinical outcome. The reported cases of stiffness and anterolateral joint pain could be attributed to excessive medial and lateral tibiofemoral posterior translation. The NRG group demonstrated good axial rotation, but this was not coupled with physiological kinematic patterns. Patellofemoral pain can be explained by a less friendly femoral-groove design. TKA clinical–functional outcome and complications were highly influenced by the bearing geometry and kinematic pattern of prosthetic designs.     

Failure of a metal-reinforced tibial post in total knee arthroplasty

Failures of the polyethylene tibial post in posterior stabilized total knee arthroplasty are usually associated with pain and knee instability. We report an unusual presentation of a tibial post failure that occurred after the polyethylene insert was revised in a posterior-stabilized total knee. The tibial post on the revised insert broke off, exposing a metal reinforcing pin. During the resulting posterior subluxations of the tibia, the metal pin articulated against the cam on the femoral component, resulting in the generation of metallic debris in the knee joint.     

全膝关节置换术中关节周围局部注药镇痛效果的研究

[目的]围手术期使用鸦片类药物或椎管内麻醉镇痛会带来很多副作用。良好的围手术期镇痛有利于康复,增加患者对医院的满意度,减少住院时间。作者做全膝关节假体周围注药疗效的研究。[方法]38名全膝关节置换患者随机分为2组:一组接受吗啡、布比卡因、甲强龙、肾上腺素,而另外一组不接受注药。围手术期镇痛方案标准化。所有的患者术后48h接受患者自控式的镇痛,随访采用标准化镇痛方案。可视模拟的疼痛评分,记录患者在术前、术后和术后6周的疼痛评分。并衡量术后特定时间点的自控镇痛消耗量,全面的镇痛要求。[结果]接受注药的患者术后24h注药组为(28.26±8.14)mg,对照组为(40.16±9.17)mg,t=4.229,P=0.00,注药组对镇痛的需求量显著降低;术后48h注药组为(48.79±11.43)mg,对照组为(66.58±10.93)mg,t=4.904,P=0.00,注药组对镇痛的要求显著降低。在术后24、48h使用的自控镇痛明显减少。术后复苏、术后4h、术后1d时的疼痛评分降低。未发现心脏和中枢神经系统的毒性。[结论]全膝关节置换术中注射多种药物显著的降低了患者自控镇痛,提高了患者满意度,并且未见明显副作用。     

Revision knee arthroplasty with a rotating-hinge design in elderly patients with instability following total knee arthroplasty

Background

Revision knee arthroplasty with a rotating-hinge design could be an option for the treatment of instability following total knee arthroplasty (TKA) in elderly patients.

Purpose

To evaluate the clinical and radiographic results of revision arthroplasties in TKAs with instability using a rotating-hinge design in elderly patients.

Methods

We retrospectively reviewed 96 rotating-hinge arthroplasties. The average age of the patients was 79 years (range, 75–86 years); the minimum follow-up was 5 years (mean, 7.3 years; range, 5–10 years). Patients were evaluated clinically (Knee Society score) and radiographically (position of prosthetic components, signs of loosening, bone loss).

Results

At a minimum followup of 5 years (mean, 7.3 years; range, 5–10 years), Knee Society pain scores improved from 37 preoperatively to 79 postoperatively, and function scores improved from 34 to 53. ROM improved on average from −15° of extension and 80° of flexion before surgery to −5° of extension and 120° of flexion at the last followup (p = 0.03). No loosening of implants was observed. Nonprogressive radiolucent lines were identified around the femoral and tibial components in 2 knees. One patient required reoperation because of a periprosthetic infection.

Conclusions

Revision arthroplasty with a rotating-hinge design provided substantial improvement in function and a reduction in pain in elderly patients with instability following TKA.

Level of evidence

Level IV, therapeutic study.     

Effect of training level on accuracy of digital templating in primary total hip and knee arthroplasty

The use of digital radiography and templating software continues to become more prevalent in orthopedics as the number of total hip arthroplasty (THA) and total knee arthroplasty (TKA) procedures increases every year. The purpose of this study was to evaluate the effect of training level on the accuracy of digital templating for primary THA and TKA. Digital radiographs of 97 patients undergoing primary THA (49 cases) and TKA (48 cases) were retrospectively templated using OrthoView digital planning software (OrthoView LLC, Jacksonville, Florida). Anteroposterior hip and lateral knee radiographs were digitally templated and compared with the actual size of the implants used intraoperatively. An implant sales representative, physician assistant, medical student (J.D.K.), resident (A.R.H.), and fellowship-trained arthroplasty surgeon (B.R.L.) templated all cases independently after a standardized orientation and were blinded to the actual component sizes used for surgery. The medical student, resident, and arthroplasty surgeon retemplated the same 97 cases 1 month later to determine intraobserver reliability. Digital templating was accurate in predicting the correct implant size in 33% of THAs and 54% of TKAs. In 73% of THAs and 92% of TKAs, digital templating was within 1 size of the actual implant used, and in 88% of THAs and 99% of TKAs, templating was within 2 sizes of the final components. In no cases did the templated implant size vary by >3 sizes from the final components. Interobserver reliability for templating THAs and TKAs showed good reliability as measured by intraclass correlation coefficient (ICC) (ICC(THA)=.70; ICC(TKA)=.86). Intraobserver reliability for templating THAs had excellent reliability for the resident and arthroplasty surgeon, with a kappa coefficient (κ) of 0.92, and good reliability for the medical student (κ=0.78). Intraobserver reliability for templating TKAs showed excellent reliability among all examiners (κ=0.90).     

15-year experience with soft tissue expansion in total knee arthroplasty

Preoperative identification of a knee at risk for wound healing after total knee arthroplasty (TKA) allows the surgeon to apply a soft tissue expansion technique to expand the available tissue for closure and healing after TKA. A consecutive series of 64 soft tissue expansions were performed for 59 cases of conflicting incisions and 5 cases of severe angular deformity, with a mean of 3.5 previous surgeries. An average 2.1 expanders were used for a total volume of 359 mL. Expansion took a mean of 70 days during which 14 minor and 7 major complications occurred. There were 8 post-TKA complications, 5 of which required a return to the operating room. Soft tissue expansion is a safe, prophylactic technique that provides adequate coverage in this complex subset of patients.     

Changes in lower extremity 3-dimensional load-bearing axes before and after mobile-bearing total knee arthroplasty

This study evaluated changes in the lower extremity 3-dimensional load-bearing mechanical axes in the anteroposterior and mediolateral directions before and at 3 weeks after mobile-bearing total knee arthroplasty. The effects of the degrees of anteroposterior constraint of the designs on the location of the load-bearing mechanical axis at the knee joint level were also assessed. We evaluated 151 knees from 134 patients with 74 knees receiving meniscal bearing-type and 77 knees receiving rotating platform-type prostheses. In the mediolateral direction, both designs showed significant improvements, whereas in the anteroposterior direction, they revealed no improvements postoperatively and were worsened significantly in meniscal bearing type. Differences in the degree of bone and soft tissue involvement for the correction of alignment may explain the findings.     

Preoperative risk factors for deep vein thrombosis in knee osteoarthritis patients undergoing total knee arthroplasty

BackgroundTo analyze the risk factors for preoperative deep vein thrombosis (DVT) in knee osteoarthritis (OA) patients undergoing total knee arthroplasty (TKA).MethodsIn this retrospective study, a total of 584 knee OA patients undergoing TKA were enrolled. General information, medical records and preoperative laboratory examination results of the patients were collected. According to the results of Doppler ultrasonography for the lower extremities, the patients were divided into DVT group and non-DVT group. Univariate and multivariate logistic regression were used to identify independent risk factors for preoperative DVT in knee OA patients undergoing TKA.ResultsThe incidence of DVT before TKA was 6.85% (40 cases). The increase of ESR (Erythrocyte Sedimentation Rate), platelet crit, IL-6 (Interleukin-6), and PCT (Procalcitonin) were associated with the development of DVT before TKA. Factors as coronary heart disease (CHD), diabetes mellitus (DM), Chronic Kidney Disease (CKD), NLR (ratio of neutrophils to lymphocytes), lower limb venous blood stasis, the time from onset to admission, RBC, PLT were identified by multivariate logistic regression to be the independent risk factors for preoperative DVT in knee OA patients undergoing TKA.ConclusionsDM, CKD, CHD, increased in ESR, IL-6 and PCT, blood stasis of the lower extremities, increased in PLT, platelet crit and the time from onset to admission, decreased in RBC, were high risk factors for preoperative DVT in knee OA patients undergoing TKA.     

Osteolysis after unidirectional and multidirectional mobile-bearing total knee arthroplasty in young patients

We questioned whether a difference exists between multidirectional and unidirectional mobile-bearing total knee arthroplasties in terms of clinical results and the prevalence of polyethylene wear and periprosthetic osteolysis. We studied 62 patients who underwent simultaneous bilateral total knee arthroplasties, with a unidirectional prosthesis implanted in 1 knee and a multidirectional one in the other. Of the patients, 9 were men and 53 were women, with a mean age of 57.6 years (35-60 years). The minimum follow-up was 11 years (mean, 11.8 years; range, 11-13 years). Preoperative and postoperative knee and functional scores were not different between the 2 groups. No knee in either group had detectable tibial polyethylene liner wear or osteolysis on radiographs or on computed tomography scans. Two (3%) knees in each group were revised.     

Magnetic resonance angiography in the management of recurrent hemarthrosis after total knee arthroplasty

Spontaneous hemarthrosis is an infrequent but disabling complication after total knee arthroplasty. The purpose of this case series is to demonstrate the utility of magnetic resonance angiography (MRA) in the evaluation of hemarthrosis after total knee arthroplasty. Patients presenting with hemarthrosis unexplained by trauma, anticoagulation, or a bleeding diathesis were retrospectively identified. Eighteen patients were referred for MRA to evaluate recurrent hemarthrosis after failing conservative therapy (n = 16) or synovectomy (n = 2). Despite artifact caused by the metallic components, diagnostic evaluation of regional vessels was made. In 12 of 13 cases that underwent embolization or synovectomy, a hypertrophic feeding artery (or arteries) was visualized on MRA. One case of negative MRA did not have subsequent surgery, and we are unable to comment on the rate of false-positives because all patients in this case series had evidence of bleeding. By characterizing the vascular anatomy and identifying a dominant artery (or arteries) supplying the hypervascular synovium, MRA can serve as a guide for subsequent embolization or synovectomy, as indicated.     

Range of motion during the perioperative period in total knee arthroplasty

INTRODUCTION: This study focused on the change in the range of motion (ROM) during the perioperative period, i.e., the preoperative and intraoperative ROM, and that on discharge, and compared the difference between posterior cruciate ligament-retaining (PCLR) and -sacrificing (PCLS) prostheses. MATERIALS AND METHODS: In this prospectively randomized study, we compared the changes in the ROM in PCLR (n = 50) and PCLS (n = 50) total knee arthroplasties. RESULTS: The mean flexion in PCLR prostheses was 130.0 degrees preoperatively, 120.0 degrees intraoperatively, and 105.0 degrees at discharge, and 125.0 degrees , 120.0 degrees , and 100.0 degrees , respectively, in PCLS. The designs did not differ statistically in each period (P > 0.05). Both designs showed significant correlations between the preoperative and intraoperative ROM, and between the preoperative and discharge ROM. Only the PCLS showed a significant correlation between the intraoperative and discharge ROM, and a significant difference was observed in correlation of rank coefficient between the two prostheses (P < 0.001). CONCLUSIONS: The PCLS design has an advantage in rehabilitation planning because of the predictable changes in the ROM during the perioperative period, although the acquired average ROM at discharge did not differ statistically.     

Asymptomatic peripheral vascular disease in total knee arthroplasty: preoperative prevalence and risk factors

Background

Although vascular disease is commonly accepted as a risk factor for wound complications and prosthetic joint infections, little is known about the preoperative prevalence of lower-extremity peripheral vascular disease in patients undergoing total knee arthroplasty (TKA). In this study, we investigated the prevalence of asymptomatic vascular disease and its risk factors.

Materials and methods

A total of 1,000 knees of 692 patients who underwent primary TKA due to osteoarthritis were preoperatively evaluated by experienced musculoskeletal radiologists using Doppler ultrasonography of the lower extremity vessels. The mean age of the patients was 74.1 years (range 65–81). Risk factors for development of peripheral vascular disease were investigated.

Results

Abnormal findings were identified in 38 knees of 32 patients (4.6 %); atherosclerotic changes in 31 knees of 25 patients (3.6 %), deep vein thrombosis (DVT) in two knees, and anomalous vessels in five knees. Three out of 31 knees with atherosclerotic changes showed severe luminal stenosis. Two knees were moderate and 26 knees showed mild changes according to our institutional criteria. Multivariate logistic regression analysis showed that age and diabetes mellitus were positively associated with vascular pathology.

Conclusion

The prevalence of incidentally detected peripheral vascular disease was significant. Three of 31 knees had severe arterial stenosis and two knees had DVT. All patients with vascular pathologies had one or more risk factors related to vascular disease. Out of those patients, age was the most important risk factor. Understanding the prevalence of vascular pathology and related risk factors in TKA candidates may be important for successful TKA.

Level of Evidence

Level III.