Comparison of Six Radiographic Projections to Assess Femoral Head/Neck Asphericity

Self Cite

Femoroacetabular impingement is considered a cause of hip osteoarthrosis. In cam impingement, an aspherical head-neck junction is squeezed into the joint and causes acetabular cartilage damage. The anterior offset angle a, observed on a lateral crosstable radiograph, reflects the location where the femoral head becomes aspheric. Previous studies reported a mean angle a of 42°i n asymptomatic patients. Currently, it is believed an angle a of 50°to 55°is normal. The aim of this study was to identify that angle a which allows impingement-free motion. In 45 patients who underwent surgical treatment for femoroacetabular impingement, we measured the angle a preoperatively, immediately postoperatively, and 1 year postoperatively. All hips underwent femoral correction and, if necessary, acetabular correction. The correction was considered sufficient when, in 90°hip flexion, an internal rotation of 20°to 25°was possible. The angle a was corrected from a preoperative mean of 66°(range, 45°-79°) to 43°(range, 34°-60°) postoperatively. Because the acetabulum is corrected to normal first, the femoral correction is tested against a normal acetabulum. We therefore concluded an angle a of 43°achieved surgically and with impingement-free motion, represents the normal angle a, an angle lower than that currently considered sufficient.

Section: Discussionmentioning

confidence: 99%

Impingement-free Hip Motion: The ‘Normal’ Angle Alpha after Osteochondroplasty

Neumann

Cui

Siebenrock

et al. 2009

Self Cite

“…For evaluating acetabular version, an appropriate anteroposterior pelvic radiograph is needed since an AP of a hip alone does not allow the viewing of bony landmarks required to control for pelvic position (rotation and/or tilt). While the typical pistol grip deformity is usually visible on an AP pelvis view, the majority of nonspherical extensions of the head are located more anterior and are better visible with a cross-table lateral or a Dunn view [40]. Nonetheless, there are anterosuperiorly located sectorial abnormalities that escape detection on conventional radiographs.…”

Section: Radiographic/mrmentioning

confidence: 98%

“…Bony abnormalities causing FAI are sufficiently welldepicted on correctly imaged radiographs in two planes [40]. For evaluating acetabular version, an appropriate anteroposterior pelvic radiograph is needed since an AP of a hip alone does not allow the viewing of bony landmarks required to control for pelvic position (rotation and/or tilt).…”

Section: Radiographic/mrmentioning

confidence: 99%

The Concept of Femoroacetabular Impingement: Current Status and Future Perspectives

Leunig

Beaulé

Ganz³

2009

Self Cite

386

269

Femoroacetabular impingement (FAI) is a recently proposed mechanism causing abnormal contact stresses and potential joint damage around the hip. In the majority of cases, a bony deformity or spatial malorientation of the femoral head or head/neck junction, acetabulum, or both cause FAI. Supraphysiologic motion or high impact might cause FAI even with very mild bony alterations. FAI became of interest to the medical field when (1) evidence began to emerge suggesting that FAI may initiate osteoarthritis of the hip and when (2) adolescents and active adults with groin pain and imaging evidence of FAI were successfully treated addressing the causes of FAI. With an increased recognition and acceptance of FAI as a damage mechanism of the hip, defined standards of assessment and treatment need to be developed and established to provide high accuracy and precision in diagnosis. Early recognition of FAI followed by subsequent behavioral modification (profession, sports, etc) or even surgery may reduce the rate of OA due to FAI.

“…An independent observer (CD) performed radiographic measurements using standard AP, false profile, and Dunn views obtained during clinical follow up [17]. These included Tönnis angle (median, 15.3°; range, 0°-55°), minimum joint space width (median, 5 mm; range, 1-45 mm), center-edge angle [30] (median, 16.5°; range, 224°to 28°), presence of crossover sign (32.4%), and alpha angle [21,25] (median, 52.8°; range, 29°-82°), with 57% of hips (41 of 72) having an alpha angle greater than 50.5°.…”

Section: Participants/study Subjectsmentioning

confidence: 99%

What Factors Predict Improvements in Outcomes Scores and Reoperations After the Bernese Periacetabular Osteotomy?

Beaulé

Dowding

Parker

et al. 2015

Background The Bernese periacetabular osteotomy (PAO) has entered its fourth decade and is frequently used for corrective osteotomy in patients with acetabular dysplasia. Although our capacity to preserve the joint after corrective osteotomy is excellent, gaining a better understanding on how well patients function after this surgery is important as well. Questions/purposes (1) What changes in patient-reported outcomes scores occur in patients treated with PAO for hip dysplasia in the setting of a single-surgeon practice? (2) What are the predictors of clinical function and survivorship? Methods All 67 patients presenting to a single surgeon's clinic with hip dysplasia treated with PAO between October 2005 and January 2013 were prospectively followed. Baseline demographic data as well as pre-and postoperative radiographic and functional measurements were obtained with a minimum of 1-year followup. Radiographic criteria included Tönnis grade, Tönnis angle, minimum joint space width, center-edge angle, presence of crossover sign, medial translation of the hip center, and alpha angle. We also used validated outcome measures including the WOMAC, the UCLA Activity Scale, and the SF-12. Multiple regression analysis was used to determine predictors of functional outcome scores. Results There were increases in WOMAC, UCLA, and SF-12 Physical scores. Higher preoperative alpha angle was associated with a lower postoperative WOMAC score (b = À0.47; 95% confidence interval [CI], À0.92 to À0.02; R 2 = 0.08; p = 0.04). The 5-year Kaplan-Meier survivorship was 94.1% (95% CI, 90.7-97.5) with reoperation (ie, hip arthroscopy and/or total hip arthroplasty) used as the endpoint for failure. With the limited numbers available, we could not identify any demographic or radiographic factors associated with reoperation. Conclusions Overall survivorship for the PAO at our center at 5 years is comparable to other clinical series with overall functional scores improving. A greater alpha angle preoperatively was associated with poorer patient-reported outcome scores. Further research is needed to determine how and when intraarticular cartilage damage associated with dysplasia needs to be addressed. Level of Evidence Level IV, therapeutic study.