Preoperative Templating Research Articles

Lessons from aviation safety: "plan your operation - and operate your plan!".

Lessons from aviation safety: "plan your operation - and operate your plan!".

Accuracy of an adjustable patient-specific guide for acetabular alignment in hip replacement surgery (Optihip).

Implant malalignment in hip arthroplasty increases the risk of revision surgery due to problems such as hip instability, wear, and impingement. Traditional instrumentation lacks accuracy and does not individualize the goal. Computer-assisted surgery (CAS) and patient-specific solutions improve accuracy but add considerably to the cost, amongst other drawbacks. We developed an adjustable mechanical device, called Optihip, which is set to a patient-specific goal preoperatively and is independent of pelvis position intraoperatively. The purpose of the present study was to evaluate Optihip's accuracy ex vivo. Acetabular components were implanted into six cadaveric specimens, 12 hips, by two surgeons, with the device individually adjusted according to preoperative templating on computed tomography (CT) images relative to defined acetabular rim landmarks; options also exist for templating on single or biplanar X-rays. Intraoperatively, the device was positioned on the corresponding anatomical landmarks allowing the insertion of a guide pin, which then defined the desired orientation of the acetabular cup during impaction. Mean absolute difference between the preoperatively planned cup alignment and final acetabular cup orientation, measured from postoperative CT images, was 2.5±1.2° for inclination and 2.5±2.2° for version with maximum values of 4.7° and 6.8°, respectively. Compared with previous in vivo reports, Optihip guided the acetabular cup orientation more accurately than conventional hip arthroplasty, and comparably to CAS or patient-specific systems, while fitting into the normal surgical workflow. Although clinical testing is required to confirm these experimental results, the positive ex vivo accuracy suggests good potential for improving revision rates and patient functional outcome.

3D templating and patient-specific cutting guides (Knee-Plan®) in total knee arthroplasty: Postoperative CT-based assessment of implant positioning

IntroductionThe precision of bone cuts and the positioning of components influence the functionality and longevity of total knee arthroplasty (TKA). The objective of this study was to evaluate the results of TKA, performed after 3D preoperative templating, with the prosthesis implanted using custom cutting guides (Knee-Plan® system, Symbios Orthopédie SA). Material and methodsThis prospective study investigated 107 TKAs. Three-dimensional preoperative templating was carried out on the surface views and CT views to analyze the deformation of the lower limb and plan the implantation. The components were positioned in an individualized manner to realign the lower limb and provide ligament balance based on bone landmarks. Final component positioning was analyzed in the three planes with a postoperative CT scan. The preoperative and 1 year follow-up IKS and WOMAC scores were collected and compared. ResultsAll the cutting guides were stable and functional. Femoral component planning was reproduced with 0±2 precision in the frontal plane (94%±3), 2±3 in the sagittal plane, and 0±2 in the transverse plane. The precision of the tibial component was reproduced with 0±2 precision in the frontal plane (93%±3) and 0±4 in the sagittal plane. The HKA angle increased from 177±7 preoperatively to 180±3 at 1 year of follow-up. The IKS and WOMAC scores were significantly improved at 1 year (P<0.0001). ConclusionThe Knee-Plan® system can be a realistic, simple, and reliable alternative to conventional cutting guides and to computer-assisted surgery for TKA implantation. Level of evidenceIV; prospective cohort study.

Continued good results with modular trabecular metal augments for acetabular defects in hip arthroplasty at 7 to 11 years.

Reconstruction of large acetabular defects remains a substantial challenge in hip arthroplasty. There remains a paucity of data on the long-term results of acetabular trabecular metal augments. The purpose of this study was to assess the survivorship, clinical outcomes, restoration of center of rotation of the hip, and radiological signs of component fixation of trabecular metal augments in the context of reconstruction of acetabular defects. Between 2002 and 2005, we performed 56 revision (n=53) and primary (n=3) THAs using trabecular metal augments in combination with a trabecular metal acetabular component. Of the 56 patients, 16 (29%) died during followup. Of the 40 surviving patients, 37 (93%) had complete radiological followup, 23 (58%) had complete outcome questionnaire followup, and 17 (42%) provided partial questionnaire responses in the clinic or over the telephone. Median followup was 110 months (range, 88-128 months). During that period, we used these implants when preoperative templating indicated that an augment would be required to achieve acetabular implant stability with restoration of the hip center of rotation. We also chose during surgery to use an augment when we could not achieve a stable acetabular trial component without one. The combination of trabecular metal augments and trabecular metal shells was used in 18% (53 of 292) of our acetabular revisions during that time. Survivorship, functional outcome (WOMAC and Oxford hip score), health status (SF-12), and osseointegration according to the criteria of Moore and presence of radiolucencies were determined. Survivorship of the augments at 10 years was 92% (95% confidence interval, 81%-97%). Four patients underwent cup revision, one for infection and three for loosening. The mean WOMAC global score was 79 (SD 17), the mean Oxford hip score 76 (SD 18), the mean physical component SF-12 score was 39 (SD 11), and the mean mental component SF-12 score was 52 (SD 9). The center of rotation was corrected from more than 35 mm above the inter-teardrop line in 48 of 56 patients preoperatively to only five of 46 postoperatively. One patient had radiographic findings suggestive of loosening, but this patient was asymptomatic. The results of the acetabular trabecular metal augments continue to be encouraging in the medium to long term with low rates of revision or loosening in this complex group of patients. We continue to recommend the use of these augments in the reconstruction of complex acetabular defects. Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Accuracy of preoperative templating in total hip arthroplasty.

To assess the accuracy of templating in total hip arthroplasty (THA). Anteroposterior pelvic radiographs of 20 men and 33 women aged 17 to 80 (mean, 60) years who underwent uncemented THA of the right (n=24) and left (n=29) sides using a single prosthesis were reviewed. A 30-mm-diameter scaling ball was placed between the patient's legs for calculating the magnification factor (MF) of the radiographs. The planned THA was templated using computer software. The positioning of the scaling ball was measured. The preoperative MF was calculated as the size of the ball on radiograph divided by the true size of the ball times 100. The true MF was calculated as the size of the cup on radiograph divided by the true size of the cup times 100. The accuracy of the preoperative MF was calculated as the preoperative MF divided by the true MF times 100. The cup size and stem size were predicted correctly (within one size error) in 87% and 92% of the patients, respectively; no template size was greater than 3 size errors. The overall mean pre- and post-operative MFs differed significantly (122% vs. 127%, p<0.001), as did the mean postoperative MFs between males and females (126% vs. 128%, p=0.006). Assuming the MF was constant, and the postoperative measurement was the most accurate, the mean accuracy of preoperative MF was 96% (range, 89.6-99.9%), whereas the relative mean height of the scaling ball was 30 (range, 1-90) mm away from the correct height. The accuracy of the preoperative MF did not correlate with body mass index, the scaling ball position, and the accuracy of cup and stem templates. If the MF of 127% is constant across different patients, using a MF of 127% is more accurate than using the scaling ball technique.

The accuracy and reliability of pre-operative templating in revision total knee arthroplasty. A comparison of analogue and digital methods

AimsTo determine whether the size of the prostheses used in revision knee arthroplasty may be accurately and reproducibly predicted using analogue or digital pre-operative templating techniques. MethodsPre-operative radiographs were templated using analogue radiographs and acetate templates, digital radiographs and acetate templates and digital radiographs and digital templating software. ResultsOverall accuracy of predicting the size of implant used at surgery was 44%. There was no significant difference in the accuracy of the various templating techniques (p = 0.098). ConclusionsTemplating in revision knee arthroplasty is neither of suitable accuracy nor reliability enough to safely recommend its use for implant size prediction.

Assessment of Accuracy of Marker Ball Placement in Pre-operative Templating for Total Hip Arthroplasty

We report the accuracy of positioning of the calibration ball in the process of pre-operative templating for total hip arthroplasty (THA). The ball should be placed in the coronal plane of the hip to provide suitable accuracy. We reviewed 112 post-operative THA radiographs where a calibration ball had been placed. We templated the femoral head size of the implant after calibrating the templating system from the ball. The calibrated femoral head diameter was compared to the known prosthetic head size. A percentage error was calculated. Overall, incorrect placement of the calibration ball resulted in a mean percentage error in templating of 6.8% (median 5.7%; range 0–26%). Such error carries implications with the templating process and may result in incorrect component sizes, leg lengths and offset.

Do we need intraoperative radiographs for positioning the femoral component in total hip arthroplasty?

Poor long-term results of total hip arthroplasty (THA) can result from femoral component misalignment. There are few reports that discuss the effectiveness of intraoperative radiographs for placing femoral components. This study is a retrospective review to find out the usefulness of intraoperative radiographs in detecting and improving the femoral component misalignment in posterior-approached primary THA. The study group included 150 primary THAs performed between September 2009 and April 2012. After the trial component insertion in lateral decubitus position, intraoperative radiography was performed. The surgeon assessed the femoral component position in three aspects: alignment, leg length, and offset. If it is not following the preoperative template, the surgeon makes the intraoperative adjustments to change the femoral component position. After the operation, postoperative radiograph was taken; the same parameters were measured and were compared to intraoperative findings. The changes in each parameter were classified into three categories: satisfactory, no change, and unsatisfactory. Among the three parameters, if one is satisfactory and the others are not unsatisfactory, we defined it as accurate positioning of the femoral component. Intraoperative adjustments were made in 122 cases (81.3%). The adjustments included changes in the component size (35.3%), component alignment (38.6%), femoral offset (14.0%), and additional femoral neck cuts (56.0%). As a result, accurate positioning was successfully achieved in 112 cases (91.8%) by taking intraoperative radiographs. Our data suggest that intraoperative radiography is a useful method for detecting the errors of placing the femoral components, and the success of a surgeon to correct those errors after detecting them intraoperatively.

Predicting the Underestimation of the Femoral Offset in Anteroposterior Radiographs of the Pelvis Using ‘Lesser Trochanter Index’: A 3D CT Derived Simulated Radiographic Analysis

We developed ‘lesser trochanter index’ (LTI) and estimated its accuracy in predicting the underestimation of offset in the anteroposterior (AP) pelvic radiographs. We reconstructed 320 simulated radiographs from the CT scans of 40 adult hips at different rotational projections of 10° increments from 30° internal rotation to 40° external rotation. Underestimation of femoral offset as a percentage was derived from the neck profile angle for all radiographs. Radiographs with an LTI value above 35 were 94% (95% CI, 89%–97%) likely to underestimate femoral offset by more than 5%. Radiographs with LTI between 0 and 30 demonstrated femoral offset within 5% of the true offset (predictive value 100%, CI 87%–100%). LTI could be a useful guide in preoperative templating of hip arthroplasty.

Comparison of custom to standard TKA instrumentation with computed tomography

There is conflicting evidence whether custom instrumentation for total knee arthroplasty (TKA) improves component position compared to standard instrumentation. Studies have relied on long-limb radiographs limited to two-dimensional (2D) analysis and subjected to rotational inaccuracy. We used postoperative computed tomography (CT) to evaluate preoperative three-dimensional templating and CI to facilitate accurate and efficient implantation of TKA femoral and tibial components. We prospectively evaluated a single-surgeon cohort of 78 TKA patients (51 custom, 27 standard) with postoperative CT scans using 3D reconstruction and contour-matching technology to preoperative imaging. Component alignment was measured in coronal, sagittal and axial planes. Preoperative templating for custom instrumentation was 87 and 79 % accurate for femoral and tibial component size. All custom components were within 1 size except for the tibial component in one patient (2 sizes). Tourniquet time was 5 min longer for custom (30 min) than standard (25 min). In no case was custom instrumentation aborted in favour of standard instrumentation nor was original alignment of custom instrumentation required to be adjusted intraoperatively. There were more outliers greater than 2° from intended alignment with standard instrumentation than custom for both components in all three planes. Custom instrumentation was more accurate in component position for tibial coronal alignment (custom: 1.5° ± 1.2°; standard: 3° ± 1.9°; p = 0.0001) and both tibial (custom: 1.4° ± 1.1°; standard: 16.9° ± 6.8°; p < 0.0001) and femoral (custom: 1.2° ± 0.9°; standard: 3.1° ± 2.1°; p < 0.0001) rotational alignment, and was similar to standard instrumentation in other measurements. When evaluated with CT, custom instrumentation performs similar or better to standard instrumentation in component alignment and accurately templates component size. Tourniquet time was mildly increased for custom compared to standard.

Improvement of femoral component size prediction using a C-arm intensifier guide and our established algorithm in unicompartmental knee arthroplasty: A report from a Chinese population

BackgroundUnicompartmental knee arthroplasty (UKA) is becoming more widely used with the recent increase in popularity of the use of minimally invasive techniques. However, it is difficult to judge about the femoral component size in UKA using preoperative templating digitally or otherwise. Even when using navigation it is impossible to control the femoral component size. The aim of this study is to develop a better pre- or intra-operative measure that will predict femoral component size. MethodsNinety-two UKA cases were studied from June 2007 to December 2011 with a mean 26-month follow-up. We developed an intra-operative C-arm intensifier guide (CAIG) method for determining femoral size instead of pre-operative templating. The accuracy of prediction of both methods was compared from a review of post-operative radiographs. In addition, we summarized all cases and developed a Chinese algorithm to determine the femoral component size pre-operatively. ResultsThere was a significant difference between templating (59%) and CAIG (92%) method (P=0.0001). In the Chinese algorithm, height based on gender and tibial size both have greater accuracy of prediction (88% and 70.7%) than the Oxford algorithm (51.1% and 59.8%). Component size distribution and optimal tibial/femoral pairing differed from those in the Oxford report. ConclusionsWe conclude that the Chinese algorithm can greatly improve the accuracy of prediction of femoral component size. In addition, CAIG-assisted implantation of a UKR is a reliable intra-operative tool and can aid size selection of the femoral component. Level of EvidenceLevel III.

A multimodal approach in total hip arthroplasty preoperative templating

Accurate preoperative planning is mandatory for a successful total hip arthroplasty (THA). Templating helps to achieve multiple technical goals, including offset restoration, leg-length equality, and components positioning. This study aims to measure how successful a new stepwise method for preoperative radiographic templating is in achieving postoperative restoration of anatomy. We measured the relationship of several radiographic landmarks on the affected limb in comparison to the unaffected limb to define the appropriate position of the components. One hundred consecutive patients with unilateral disease undergoing THA were retrospectively analyzed. The preoperative templates were compared with the postoperative radiographs. Accuracy in achieving the desired offset, leg-length discrepancy within 5mm, was 93% and 100% respectively. Acetabular component positioning within 2° was replicated in 92%. We conclude that this technique can help the surgeon to accurately reproduce the anatomy of the contralateral unaffected hip.

Prediction of three-dimensional femoral offset from AP pelvis radiographs in primary hip osteoarthritis

BackgroundIn pre-operative planning for total hip arthroplasty (THA), femoral offset (FO) is frequently underestimated on AP pelvis radiographs as a result of inaccurate patient positioning, imprecise magnification, and radiographic beam divergence. The aim of the present study was to evaluate the accuracy and reliability of predicting three-dimensional (3-D) FO from standardised AP pelvis radiographs. MethodsIn a retrospective cohort study, pre-operative AP pelvis radiographs, AP hip radiographs and CT scans of a consecutive series of 345 patients (345 hips, 146 males, 199 females, mean age 60 (range: 40–79) years, mean body-mass-index 27 (range: 19–57)kg/m2) with primary end-stage hip OA were reviewed. Patients were positioned according to a standardised protocol and all images were calibrated. Using validated custom programmes, FO was measured on corresponding radiographs and CT scans. Measurement reliability was evaluated using intra-class-correlation-coefficients. To predict 3-D FO from AP pelvis measurements and to assess the accuracy compared to CT, the entire cohort was randomly split into subgroups A and B. Gender specific regression equations were derived from group A (245 patients) and the accuracy of prediction was evaluated in group B (100 patients) using Bland–Altman plots. ResultsIn the entire cohort, mean FO was 39.2mm (95%CI: 38.5–40.0mm) on AP pelvis radiographs, 44.1mm (95%CI: 43.4–44.9mm) on AP hip radiographs and 44.6mm (95%CI: 44.0–45.2mm) on CT scans. In group B, we observed no significant difference between gender specific predicted FO (males: 48.0mm, 95%CI: 47.1–48.8mm; females: 42.0mm, 95%CI: 41.1–42.8mm) and FO as measured on CT (males: 47.7mm, 95%CI: 46.1–49.4mm, p=0.689; females: 41.6mm, 95%CI: 40.3–43.0mm, p=0.607). ConclusionsThe present study suggests that FO can be accurately and reliably predicted from AP pelvis radiographs in patients with primary end-stage hip osteoarthritis. Our findings support the surgeon in pre-operative templating on AP-pelvis radiographs and may improve offset and limb length restoration in THA without the routine performance of additional radiographs or CT.

Preoperative Templating and Computer-Assisted Total Knee Arthroplasty for Arthritic Valgus Knee

We reported the functional outcomes, component alignment and optimal thickness of the tibial inserts and joint line changes of 21 arthritic valgus knee deformities using preoperative templating and computer-assisted total knee arthroplasty(TKA). The osseous cut was modified using a novel preoperative templating technique. Soft tissue balance and component implantation were implemented with the aid of a computed tomography-free navigation system. The arthritic valgus knees had clinical, and functional improvement of the knee Society scores and Lysholm scores postoperatively, at an average of 37.8 ± 7.2 months. The mean anatomic axis (15.2° ± 4.5° vs. 6.1° ± 1.4°) and mechanical axis (8.3° ± 5.2° vs. 0.28° ± 1.6°) were also significantly improved postoperatively. The mean thickness of tibial inserts and joint line changes was 10.7 ± 1.46 mm and 0.1 ± 1.4 mm. This computer-assisted technique with preoperative radiographic templating is an alternative strategy to improve TKA results in arthritic valgus knees.

Double dome osteotomy for the treatment of cubitus varus in children

The purpose of this study was to report double dome osteotomy used to correct paediatric cubitus varus and to avoid lateral prominence after correction. Eighteen children with cubitus varus underwent double dome osteotomy. Preoperative templating created from radiographs was used to determine the bone cuts. Double dome osteotomy created a proximal and distal cut, then varus deformity and sagittal alignment were corrected. The osteotomies were fixed with K-wires and immobilised in a long-arm cast. Radiographics and clinical histories were evaluated. Ulno-humeral angle pre and postoperative, range of motion and lateral prominent index were evaluated. The osteotomy was performed in 18 patients, with an average age of 7.5 years. All patients ended up with flexion of 130° or greater with full and symmetrical pronation and supination. The average ulno-humeral angle difference compared to the uninjured side was 3.27°. The mean of the lateral prominent index was -0.91. The mean follow up was 50.3 months (30-115 months). All of the patients had excellent clinical and radiographic alignment. No revisions were made in this series. One transient radial nerve palsy and one superficial infection occurred. This series demonstrates that double dome osteotomy can provide reliable correction of varus deformity and prevent lateral prominence with a minimal complication rate.

The Human Knee: Gross, Microscopic, Surgical, and Radiological Anatomy

The Human Knee: Gross, Microscopic, Surgical, and Radiological Anatomy

Preoperative Templating Before Spinal Fusion Using a Fluoroscopic Multiplanar Imaging System is as Accurate as CT Scan and Uses Substantially Less Radiation

Many surgeons utilize preoperative multiplanar imaging for surgical planning before fusion surgery using pedicle screw instrumentation. Computed tomographic (CT) scan is often used but limited by non-weight-bearing images and high-ionizing radiation. The purpose of this study was to compare pedicle length and width measurements using a multiplanar fluoroscopic imaging system and CT with gross measurements to validate the accuracy of multiplanar fluoroscopic imaging and compare relative radiation exposure between techniques. Thirteen intact cadaveric lumbar spine segments were imaged using multiplanar fluoroscopic imaging and conventional CT scan using a low-dose pediatric protocol. At each level and each imaging modality, the 26 pedicles were measured digitally for width and pedicle screw length in accordance with typical presurgical planning procedures. All images were independently measured by 3 observers. After measurement, the specimens were sectioned using a microsurgical saw to facilitate anatomic measurements using calipers. Measurements of the multiplanar fluoroscopic imaging and CT were compared with direct anatomic measurements to quantitate and compare measurement accuracy of CT and fluoroscopic imaging. At the time of image acquisition, radiation exposure from each modality was quantified to allow for comparison of radiation exposures. CT and multiplanar fluoroscopy had similar agreement with gross measurements with respect to pedicle width and length, with κ values for comparison of CT and fluoroscopy with gross measurements falling between 0.61 and 0.73. Both modalities underestimated pedicle width (by 1.9 mm for both modalities) and length (5.5 mm for CT, 6.6 mm for fluoroscopy). Interobserver reliability was higher for fluoroscopy versus CT. High-dose fluoroscopic imaging used 31% of the radiation exposure for CT. Multiplanar fluoroscopic imaging provides comparable diagnostic preoperative planning to CT scan in an experimental cadaveric model. The use of multiplanar fluoroscopic imaging resulted in between 69% and 85% less radiation exposure than conventional CT scan using pediatric settings. This study demonstrates similar results from simulated preoperative templating using fluoroscopic imaging compared with CT scan but with less radiation exposure.

Are the Left and Right Proximal Femurs Symmetric?

The contralateral femur frequently is used for preoperative templating for THA or hemiarthroplasty when the proximal femur is deformed by degenerative changes or fracture. Although femoral symmetry is assumed in these situations, it is unclear to what degree the contralateral femur is symmetrical. We therefore defined the degree of asymmetry between left and right proximal femurs and determined whether it was affected by demographics and proximal femoral anatomy. We obtained 160 paired femurs from individuals (20-40 years old), evenly distributed for gender and ethnicity (African-American and Caucasian). The height and weight of the individuals were recorded. We measured the femoral head diameter, minimal femoral neck diameter in the AP and cephalocaudal (CC) planes, and the AP femoral diaphyseal diameter. The absolute and percent differences were determined. All femoral measurements showed an absolute difference less than 2 mm and a percent asymmetry and difference less than 2% for the femoral head, less than 4% for the femoral neck, and less than 3.5% for the femoral shaft. We found no correlation or predictive value between absolute differences and asymmetry and age, ethnicity, gender, or weight. Height was negatively associated with femoral head differences and thus increased symmetry of the femoral head. Our data support assumptions of substantial symmetry of the proximal femur and highlights that asymmetry is not affected by demographics or the size of the proximal femur. Asymmetry tends not to occur in isolated segments of the femur.

Clavicular Bone Tunnel Malposition Leads to Early Failures in Coracoclavicular Ligament Reconstructions

Background: Modern techniques for the treatment of acromioclavicular (AC) joint dislocations have largely centered on free tendon graft reconstructions. Recent biomechanical studies have demonstrated that an anatomic reconstruction with 2 clavicular bone tunnels more closely matches the properties of native coracoclavicular (CC) ligaments than more traditional techniques. No study has analyzed tunnel position in regard to risk of early failure. Purpose: To evaluate the effect of clavicular tunnel position in CC ligament reconstruction as a risk of early failure. Study Design: Case series; Level of evidence, 4. Methods: A retrospective review was performed of a consecutive series of CC ligament reconstructions performed with 2 clavicular bone tunnels and a free tendon graft. The population was largely a young, active-duty military group of patients. Radiographs were analyzed for the maintenance of reduction and location of clavicular bone tunnels using a picture archiving and communication system. The distance from the lateral border of the clavicle to the center of each bone tunnel was divided by the total clavicular length to establish a ratio. Medical records were reviewed for operative details and functional outcome. Failure was defined as loss of intraoperative reduction. Results: The overall failure rate was 28.6% (8/28) at an average of 7.4 weeks postoperatively. Comparison of bone tunnel position showed that medialized bone tunnels were a significant predictor for early loss of reduction for the conoid (a ratio of 0.292 vs 0.248; P = .012) and trapezoid bone tunnels (a ratio of 0.171 vs 0.128; P = .004); this correlated to an average of 7 to 9 mm more medial in the reconstructions that failed. Reconstructions performed with a conoid ratio of ≥0.30 were significantly more likely to fail (5/5, 100%) than were those performed lateral to a ratio of 0.30 (3/23, 13.0%) (P < .01). There were no failures when the conoid ratio was <0.25 (0/10, 0%). Conoid tunnel placement was also statistically significant for predicting return to duty in our active-duty population. Conclusion: Medial tunnel placement is a significant factor in risk for early failures when performing anatomic CC ligament reconstructions. Preoperative templating is recommended to evaluate optimal placement of the clavicular bone tunnels. Placement of the conoid tunnel at 25% of the clavicular length from the lateral border of the clavicle is associated with a lower rate of lost reduction and a higher rate of return to military duty.

Template-directed Instrumentation in Total Knee Arthroplasty: Cost Savings Analysis

The use of digital radiography and templating software in total knee arthroplasty (TKA) continues to become more prevalent as the number of procedures performed increases every year. Template-directed instrumentation (TDI) is a novel approach to surgical planning that combines digital templating with limited intraoperative instruments. The purpose of this study was to evaluate the financial implications and radiographic outcomes of using TDI to direct instrumentation during primary TKA. Over a 1-year period, 82 consecutive TKAs using TDI were retrospectively reviewed. Patient demographics and preoperative templated sizes of predicted components were recorded, and OrthoView digital planning software (OrthoView LLC, Jacksonville, Florida was used to determine the 2 most likely tibial and femoral component sizes for each case. This sizing information was used to direct component vendors to prepare 3 lightweight instrument trays based on these sizes. The sizes of implanted components and the number of total trays required were documented. A cost savings analysis was performed to compare TDI and non-TDI surgical expenses for TKA. In 80 (97%) of 82 cases, the prepared sizes determined by TDI using 3 instrument trays were sufficient. Preoperative templating correctly predicted the size of the tibial and femoral component sizes in 90% and 83% of cases, respectively. The average number of trays used with TDI was 3.0 (range, 3-5 trays) compared with 7.5 (range, 6-9 trays) used in 82 preceding non-TDI TKAs. Based on standard fees to sterilize and package implant trays (approximately $26 based on a survey of 10 orthopedic hospitals performing TKA), approximately $9612 was saved by using TDI over the 1-year study period. Overall, digital templating and TDI were a simple and cost-effective approach when performing primary TKA.