Erin L. Ruh

Are Patient-specific Cutting Blocks Cost-effective for Total Knee Arthroplasty?

BackgroundUsing patient-specific cutting blocks for TKA increases the cost to the hospital for these procedures, but it has been proposed they may reduce operative times and improve implant alignment, which could reduce the need for revision surgery.Questions/purposesWe compared TKAs performed with patient-specific cutting blocks with those performed with traditional instrumentation to determine whether there was improved operating room time management and component coronal alignment to support use of this technology.MethodsWe retrospectively reviewed 57 patients undergoing primary TKAs using patient-specific custom cutting blocks for osteoarthritis and compared them with 57 matched patients undergoing TKAs with traditional instrumentation during the same period (January 2009 to September 2010). At baseline, the groups were comparable with respect to age, sex, and BMI. We collected data on operative time (total in-room time and tourniquet time) and measured component alignment on plain radiographs.ResultsOn average, TKAs performed with patient-specific instrumentation had similar tourniquet times (61.0 versus 56.2 minutes) but patients were in the operating room 12.1 minutes less (137.2 versus 125.1 minutes) than those in the standard instrumentation group. We observed no difference in the femorotibial angle in the coronal plane between the two groups.ConclusionsPatient-specific instrumentation for TKA shows slight improvement in operating room time management but none in component alignment postoperatively. Therefore, routine use of this new technology may not be cost-effective in its current form.Level of EvidenceLevel III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Patient specific cutting blocks are currently of no proven value

Patient specific cutting guides generated by preoperative Magnetic Resonance Imaging (MRI) of the patients extremity have been proposed as a method of improving the consistency of Total Knee Arthroplasty (TKA) alignment and adding efficiency to the operative procedure. The cost of this option was evaluated by quantifying the savings from decreased operative time and instrument processing costs compared to the additional cost of the MRI and the guide. Coronal plane alignment was measured in an unselected consecutive series of 200 TKAs, 100 with standard instrumentation and 100 with custom cutting guides. While the cutting guides had significantly lower total operative time and instrument processing time, the estimated

Accuracy of acetabular component position in hip arthroplasty.

322 savings was overwhelmed by the

Do Patients Return to Work After Hip Arthroplasty Surgery

1,500 additional cost of the MRI and the cutting guide. All measures of coronal plane alignment were equivalent between the two groups. The data does not currently support the proposition that patient specific guides add value to TKA.

Does Standing Affect Acetabular Component Inclination and Version After THA

BACKGROUND Acetabular component malposition is linked to higher bearing surface wear and component instability. Outcomes following total hip arthroplasty and surface replacement arthroplasty depend on multiple surgeon and patient-dependent factors. The purpose of this study was to examine the frequency in which acetabular components are placed within a predetermined target range. METHODS We evaluated postoperative anteroposterior pelvic radiographs for every consecutive primary total hip arthroplasty and surface replacement arthroplasty completed from 2004 to 2009 at a single institution. Acetabular component abduction and anteversion angles were determined using Martell Hip Analysis Suite software. We defined target ranges for abduction and anteversion for both total hip arthroplasty (30° to 55° and 5° to 35°, respectively) and surface replacement arthroplasty (30° to 50° and 5° to 25°, respectively). Surgeon and patient-related factors were analyzed for risk associated with placing the acetabular component outside the target range. RESULTS Of the 1549 total hip arthroplasties, 1435 components (93%) met our abduction target, 1472 (95%) met our anteversion target, and 1363 (88%) simultaneously met both targets. Of the 263 surface replacement arthroplasties, 233 components (89%) met our abduction target, 247 (94%) met our anteversion target, and 220 (84%) simultaneously met both targets. When previously published target ranges of abduction (30° to 45°) and anteversion (5° to 25°) angles were used, only 665 total hip replacements (43%) met the abduction target, 1325 (86%) met the anteversion target, and 584 (38%) simultaneously met both targets. Of the surface replacement arthroplasties, 181 (69%) met the abduction target, 247 (94%) met the anteversion target, and 172 (65%) simultaneously met both targets. Low-volume surgeons were 2.16 times more likely to miss target component position compared with high-volume surgeons (p = 0.002). The odds of missing the target increased by ≥ 0.2 for every 5 kg/m2 increase in body mass index. Minimally invasive approaches, diagnosis, years of surgical experience, femoral head size, and age of the patient did not affect component position. CONCLUSIONS Increased odds of component malposition were found with lower-volume surgeons and higher body mass index. No other variables had a significant effect on component placement. LEVEL OF EVIDENCE Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Do Patient-specific Guides Improve Coronal Alignment in Total Knee Arthroplasty?

Improvements in total hip arthroplasty implant design and advances in bearing materials, including modern surface arthroplasty, have resulted in these procedures being performed in younger and more active patients. There is limited information in the literature to provide to patients, employers, and insurance companies about returning to work after hip arthroplasty surgery. We conducted a multicenter telephone survey on 943 patients younger than 60 years with a University of California, Los Angeles, activity score of 6 or higher (regularly participates in moderate activities) who underwent hip arthroplasty surgery between 2005 and 2007 at a minimum of 1 year after surgery. We found that most young, active patients employed before surgery can expect to return to work (90.4%), with the vast majority returning to their preoperative occupation, and very few (2.3%) were limited in their ability to return to work because of their operative hip.

High Level of Residual Symptoms in Young Patients After Total Knee Arthroplasty

BackgroundAvoiding complications after hip arthroplasty with hard-on-hard bearings, especially metal-on-metal, correlates with the position of the acetabular component. Supine imaging with conventional radiography has traditionally been utilized to assess component inclination (abduction), as well as anteversion, after THA and surface replacement arthroplasty (SRA). However, most adverse events with hard bearings (excessive wear and squeaking) have occurred with loading. Standing imaging, therefore, should provide more appropriate measurements.Questions/purposesWe determined whether standing changed standard measurements of acetabular component position using a novel biplanar imaging system compared to traditional supine imaging.MethodsWe performed simultaneous biplanar standing imaging of the lower extremity with a novel imaging system using low radiation collimated beam on 46 patients who underwent THA (23) or SRA (23). Patients who had previously undergone THA had standard CT scans performed. For patients who underwent SRA, we compared acetabular inclination in the supine versus double-limb and single-limb standing.ResultsStanding anteversion differed from supine anteversion by greater than 5° for 12 of 23 patients who underwent THA (range, 5°–16°). For patients who underwent SRA, 13 of 23 patients exhibited a difference of greater than 3° in inclination between supine and double-limb standing images, and six of 23 patients exhibited a difference of greater than 3° in inclination between supine and single-limb standing images.ConclusionsStanding changed the acetabular inclination and version in a substantial percentage of patients undergoing hip arthroplasty.