Brent A. Lanting

Effect of Taper Design on Trunnionosis in Metal on Polyethylene Total Hip Arthroplasty.

This study examines how taper design affects corrosion and fretting at the head trunnion surface. All hip prostheses retrieved between 1999 and 2013 with 28mm/+0 heads were selected, resulting in 44 cobalt-chrome-on-polyethylene implants, representing six taper designs. Mean implantation time: 8.9±3.7years. The femoral head tapers were scored for fretting and corrosion using the Goldberg scale as both a combined score and by three zones (apex, central and base). There was no difference in age (P=0.34), BMI (P=0.29), or implantation time (P=0.19) between taper groups. The 11/13 taper had the highest combined corrosion and fretting score, but no difference (P=0.22) between groups for combined scores (P=0.22 for corrosion, P=0.19 for fretting). In a zone-specific analysis, the 11/13 taper had highest corrosion score at base zone (P=0.02). Taper design had a significant effect on corrosion at base of trunnion.

In-Hospital Cost Analysis of Total Hip Arthroplasty: Does Surgical Approach Matter?

The purposes of this study were to determine the impact of surgical approach on costs of total hip arthroplasty (THA) from a hospital perspective and to provide an updated cost estimation of THA. A prospective, microcosting analysis was performed on 118 patients undergoing a THA through an anterior, lateral, or posterior approach. We determined that overall costs (intraoperative costs and hospital stay) were significantly less for the anterior (

Incidence of Perioperative Events in Single Setting Bilateral Direct Anterior Approach Total Hip Arthroplasty

7300.22; 95% confidence interval [CI], 7064.49-7535.95) vs lateral (

The effect of radial head implant length on radiocapitellar articular properties and load transfer within the forearm.

7853.10; 95% CI, 7577.29-8128.91; P = .031) and anterior vs posterior approach (

Radiostereometric analysis using clinical radiographic views: Validation measuring total hip replacement wear.

8287.46; 95% CI, 7906.42-8668.51; P < .001). A reduction in hospital length of stay when THA was performed through an anterior approach contributed significantly to an overall reduction in costs from a hospital perspective.

Knee manipulation under anaesthetic following total knee arthroplasty

The peri-operative complication rates of a single setting bilateral direct anterior approach (DAA) total hip arthroplasty (THA) are not well known. All single setting (90) bilateral DAA THA patients were reviewed. Blood loss was 632 mL for single setting bilateral DAA procedures. Intra-operative and post-operative complication rates for single setting bilateral DAA THA were low.

Clinical Impact of Trunnion Wear After Total Hip Arthroplasty

Background: The effect of radial head implant length on forearm biomechanics is not well understood. This study examined the influence of an increase or a decrease in radial head implant length on forearm load transfer as measured by interosseous membrane (IOM) tension and changes in radiocapitellar joint contact properties. Methods: An upper extremity simulator was used to examine 6 cadaveric specimens with 5 different radial head implant lengths (−4 mm, −2 mm, anatomically correct, +2 mm, and +4 mm). A load-sensing device was woven into the fibers of IOM to quantify its tension. An interpositional pressure measurement sensor was used to determine radiocapitellar joint contact area and pressure. Axial loads of 160 N were applied to the forearm through active pronation and supination with the elbow fixed at 90 degrees of flexion. Results: Increasing radial head implant length by 4 mm unloaded the IOM in all cases. Decreasing implant length by 4 mm significantly increased the IOM tension (P = 0.005). No significant differences were found in IOM tension between the correct head implant length and the −2 mm implant (P = 0.29). Contact pressure significantly increased with increasing radial head implant length (P = 0.021) and contact area diminished with both an increase and a decrease in radial head implant length, but this was not statistically significant (P = 0.051). Conclusions: Increasing radial head implant length decreased IOM tension and increased radiocapitellar joint contact pressure. Clinical Relevance: These findings illustrate the importance of precise restoration of radial length when performing a radial head replacement. If the native radial head length is difficult to accurately assess, avoid increasing the length of the radial head to prevent detrimental changes in the biomechanics of the forearm and the potential for clinically important radiocapitellar joint pathology.

Dislocated Polyethylene Inserts in Fixed-Bearing Total Knee Arthroplasty

Radiostereometric analysis (RSA) is a stereo X‐ray technique used in clinical research studies to evaluate micro‐motion and wear of orthopaedic implants within bone. While highly accurate and precise, its adoption has been limited due to technical requirements such as the need for implanted marker beads and radiograph view angles determined by a calibration cage. We propose a new technique that separates the calibration procedure from the patient examination, enabling clinical radiograph views to be used for RSA measurements. The concept of a reference plate was adapted to establish the link between calibration procedure and patient examination procedure for cassette radiography, which may not be necessary for digital radiography. A hip wear phantom was used to validate this technique by comparing the error and repeatability of the novel procedure with that of conventional RSA. Femoral head penetration was measured versus the acetabular cup (head/cup) and marker beads in the acetabular liner (head/liner). Conventional RSA had lower inferior–superior average error (p = 0.03 for head/cup) while the modified RSA had lower anterior–posterior average error (p = 0.01). Average error was greater but not significantly so for the medial–lateral (p = 0.06) and 3D (p = 0.97) measurements. The head/liner method had lower average errors (p < 0.0001) for both procedures, but did not affect repeatability, which was similar between techniques. The novel procedures average error and repeatability was therefore, similar to conventional RSA. This new technique could be applied to any joint with two clinical radiograph view angles pending further validation in subjects.

A marker-based technique for visualizing radiolucent implant components in radiographic imaging†

The purpose of this study was to compare clinical outcomes of total knee arthroplasty (TKA) after manipulation under anaesthesia (MUA) for post-operative stiffness with a matched cohort of TKA patients who did not requre MUA. In total 72 patients (mean age 59.8 years, 42 to 83) who underwent MUA following TKA were identified from our prospective database and compared with a matched cohort of patients who had undergone TKA without subsequent MUA. Patients were evaluated for range of movement (ROM) and clinical outcome scores (Western Ontario and McMaster Universities Arthritis Index, Short-Form Health Survey, and Knee Society Clinical Rating System) at a mean follow-up of 36.4 months (12 to 120). MUA took place at a mean of nine weeks (5 to 18) after TKA. In patients who required MUA, mean flexion deformity improved from 10° (0° to 25°) to 4.4° (0° to 15°) (p < 0.001), and mean range of flexion improved from 79.8° (65° to 95°) to 116° (80° to 130°) (p < 0.001). There were no statistically significant differences in ROM or functional outcome scores at three months, one year, or two years between those who required MUA and those who did not. There were no complications associated with manipulation. At most recent follow-up, patients requiring MUA achieved equivalent ROM and clinical outcome scores when compared with a matched control group. While other studies have focused on ROM after manipulation, the current study adds to current literature by supplementing this with functional outcome scores.

Do Changes in Patellofemoral Joint Offset Lead to Adverse Outcomes in Total Knee Arthroplasty With Patellar Resurfacing? A Radiographic Review

Trunnionosis, characterized by corrosion and fretting of the taper, is a well-known entity commonly demonstrated in retrieval specimens. While there have been a number of recent reports regarding the potential for adverse local tissue reactions related to trunnionosis, it remains a relatively infrequent cause for failure of total hip replacement implants.A number of factors, including both biomechanical and bioelectrochemical factors, have a known impact on the development and severity of trunnionosis. Furthermore, specific implant design and material-related factors have been shown to influence the risk of trunnionosis leading to adverse local tissue reactions.Retention of a well-fixed femoral stem, in spite of corrosion of the male taper junction, is acceptable in the majority of cases.A ceramic head, often in combination with a titanium adaptor sleeve, is the most common replacement reported in the current literature to treat trunnionosis.In patients with modular-neck total hip replacements, revision of the femoral stem is likely required if corrosion at the modular neck-stem junction is encountered.