Total hip arthroplasty requires proper sizing and placing of implants to ensure excellent outcomes and reduce complications. Calculation of femoral offset is an important consideration for optimal reconstruction of the hip biomechanics. Femoral offset can be measured on plain films or with flouroscopy if the x-ray beam is perpendicular to the plane determined by the angle between the neck axis and femoral shaft axis. This distance is evident only with the femur in the correct degree of rotation. Though pre-operative templating for femoral component size and offset is a regular accepted practice, a consistent method for assessing correct femoral rotation on the AP x-ray view has not been established. The purpose of the current study was to establish and validate a method for identifying radiographic landmarks on the proximal femur that would reliably indicate that the femur was in the proper degree of rotation to represent the true offset from the head center to shaft center.Background
Purpose/Hypthesis
Over the past 15 years Anterior Approach (AA) THA has shown a dramatic increase in adoption by surgeons (over 30%) and choice by patients with a corresponding decrease in the percentage of hips performed with traditional posterior and lateral approaches. I began AA in 1996 in order to solve the classic problems of potential dislocation associated with posterior approach and potential abductor weakness associated with the lateral (Harding) approach. Surgeon education on AA began in 2013 and has accelerated since. AA is usually performed with the aid of an orthopaedic table which facilitates exposure though many cases are also performed on a standard operating table. Intraoperative image intensification has provided real-time feedback and accuracy for cup position leg length and offset and is facilitated by the supine position and a radiolucent orthopaedic table, however, AA can be performed without it. Earlier functional recovery with decreased post-operative pain is the best documented benefit of AA as well as decreased dislocation rate. My own point of view is to take advantage of a switch to AA to improve more than your surgical approach. Improve also hip biomechanics, cup position, ease of surgery, bone preparation, and soft tissue handling. A proven and repeatable technique and use of available technologies will facilitate this.
For learning any new technique the main principle to follow is: learn the technique thoroughly from start to finish and adopt it as taught, without attempting to modify it until you are very familiar with it. Orthopaedic table enhanced anterior approach THA (ATHA) is at this point a well-established teachable and repeatable technique though its safety and efficacy depends on adherence to details. These technical details have evolved to become part of the technique since I first taught it at a course in 2003. The technical details and innovations have utilised the invaluable input from high volume expert surgeons as well as from less experienced surgeons taking on the challenges of learning. Considering anterior approach (AA), three technical aspects can be a “mental block” for the uninitiated surgeon: 1) supine position, 2) the orthopaedic table, 3) checking cup position, leg length and offset with the image intensifier/C-arm. Keep in mind that though you may have been initially trained and experienced with lateral position, a flat table and no x-ray checks, these three technical aspects greatly facilitate Anterior Approach and enhance its repeatability, safety, accuracy and overall “ease of use”. Anterior approach technical instruction is available at a number of venues and the preceding is consistent with the surgeon developed technique taught at courses. Visiting a surgeon who is expert in AA can also provide an effective supplemental educational experience.
The ultimate goal of surgery for acetabular fractures is hip joint preservation for the rest of the patient’s life. However, besides Letournel’s series, long term survi-vorship in this predominantly young patient group has never been published in a very large series. The aim of this study was to determine the cumulative 20-year sur-vivorship of the hip after fixation of acetabular fractures and to identify factors predicting the need for total hip arthroplasty. A Kaplan-Meier survivorship analysis of 1218 consecutive surgically treated acetabular fractures was carried out. 816 fractures were available for analysis with a mean follow up of 10.3 years (range 2–29 years). All the surgeries were performed by a single surgeon in accordance to an established treatment protocol based on Letournel’s principles. Inclusion criteria were a minimum follow-up of two years or failure at any time. Failure was defined as conversion to total hip arthroplasty of hip arthrodesis. A Cox-regression analysis identified significant risk factors predicting the need for total hip arthroplasty. Analyzed parameters comprised data on patient history, preoperative clinical examination, associated injuries, fracture pattern, radiographic and intra-operative features, and the accuracy of reduction. The cumulative 20-years survivorship was 79% (95% CI, 76–81%). Statistically significant factors influencing the need for artificial hip replacement/arthrodesis were: age over 40 years (Hazard ratio [HR] 2.4), femoral head damage (HR 2.6), acetabular impaction (HR 1.5), postoperative incongruence of the acetabular roof (2.9), involvement of the posterior wall (HR 1.6), anterior dislocation (5.9), initial displacement >
20mm (HR 1.6), and a malreduction with residual displacement >
1mm (HR 3.0). There was a significantly different survivorship of the individual fracture types. The worst survivorship occurred in anterior wall fractures (34% at 20 years) and the best survivorship in both column fractures (87% at 20 years). The accuracy of reduction improved significantly over time. In summary, the hip joint can be successfully preserved and prosthetic replacement avoided in 79% of displaced acetabular fractures at 20 years. Many of the factors influencing the long term prognosis are already determined at the time of injury. The factors that can be influenced by the surgeon are anatomic reduction, achievement of congruency of the acetabular roof and correction of marginal impaction. The presented unique results even exceed Letournel’s series in size and follow up. Therefore, they provide benchmark data for any type of comparative evaluation studies dealing with surgical treatment of acetabular fractures in future.
There has been considerable debate regarding the factors that predict clinical and radiographic outcomes in patients with acetabular fractures and associated posterior hip dislocations. To identify variables associated with clinical and radiographic outcomes. Utilizing a prospective database of acetabular fractures, we identified patients with posterior hip dislocations operatively managed within three weeks of injury and having a minimum of two years of follow up. Demographic information, operative findings, and outcomes were recorded. We conducted a series of uni-variable analyses to determine whether any independent variables were significantly associated with the dependent variable. Among one hundred and nine eligible patients with posterior hip dislocations, the most common fracture types included the posterior wall and transverse with associated posterior wall fractures. An anatomic reduction of the fracture was achieved in ninety-six patients. At their most recent follow up, the majority of patient maintained a good to excellent radiographic grade. Of those who underwent clinical outcome grading (ninety-four patients), 83% achieved good or excellent outcomes. Overall radiographic grade correlated with each domain of the clinical grade including ambulation, range of motion, and pain. Quality of fracture reduction was identified as the only significant predictor of radiographic grade, clinical function, and development of post-traumatic arthritis. All patients with poor reductions and imperfect reductions, respectively, had developed arthritis compared to 24% of patients with anatomic reductions. Our findings support Letournel’s report that quality of the fracture reduction remains the most important factor associated with outcome in patients with acetabular fractures and concomitant posterior hip dislocations. Funding: This study was funded by a research grant from Stryker Orthopaedics, Los Angeles, California. Dr. Bhandari was funded, in part, by a fellowship from AO International, Davos, Switzerland and AO North America, Paoli, Pennsylvania.
We aimed to identify variables associated with clinical and radiological outcome following fractures of the acetabulum associated with posterior dislocation of the hip. Using a prospective database of 1076 such fractures, we identified 109 patients with this combined injury managed operatively within three weeks and followed up for two or more years. The patients had a mean age of 42 years (15 to 79), 78 (72%) were male, and 84 (77%) had been involved in motor vehicle accidents. Using multivariate analysis the quality of reduction of the fracture was identified as the only significant predictor of radiological grade, clinical function and the development of post-traumatic arthritis (p <
0.001). All patients lacking anatomical reduction developed arthritis whereas only 25.5% (24 patients) with an anatomical reduction did so (p = 0.05). The quality of the reduction of the fracture is the most important variable in forecasting the outcome for patients with this injury. The interval to reduction of the dislocation of the hip may be less important than previously described.