Arthroscopic appearance and treatment of impingement cysts at femoral head-neck junction.

PURPOSE: To study the arthroscopic appearance and treatment of impingement cysts and to propose their potential intraoperative value for correct femoral osteochondroplasty in femoroacetabular impingement (FAI). METHODS: We performed a single-surgeon, retrospective study of 152 consecutive hip arthroscopies in 141 patients treated for FAI due to cam, localized pincer, or mixed FAI. Radiographic (conventional radiographs and magnetic resonance arthrography) cyst sizes and locations as well as the arthroscopic appearance were recorded. RESULTS: On the preoperative radiographs, impingement cysts were radiographically visible in 18% of treated FAI patients (26 of 141); 15% of these patients (4 of 26) had more than 1 cyst. Age was the only independent predictor of cysts, with a 7-year shift to a mean age of 42 years. The majority of cysts were located in the anterosuperior quadrant of the femoral head-neck junction (93%), the mean diameter of cysts was 7.0 mm, with a range from 3.7 to 15.1 mm. During surgery, only a few were arthroscopically identifiable, with a pit-like (3 of 26) or crater-like appearance (3 of 26) (i.e., surface alterations) for the larger cysts. The majority of cysts (20 of 26) became evident, however, after unroofing of the area of cam FAI. Cysts were associated with labral (25 of 26) and/or chondral lesions (23 of 26). Small cysts were completely removed during femoral osteochondroplasty, whereas larger cysts were only resected until impingement-free range of motion was reached. No neck fractures occurred in this series. CONCLUSIONS: Impingement cysts were present on 1 in 6 radiographs in patients undergoing hip arthroscopy for FAI and were found most commonly in older patients. The cysts predictably occur within the epicenter of the femoral-induced impingement. Whereas surface alterations are rare (6 of 26), the content and base of the unroofed cyst are consistent. Most cysts are completely excised as part of the femoral impingement correction and may be used as a confirmation that arthroscopic cam resection has been performed at the correct site. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Reliability and agreement of measures used in radiographic evaluation of the adult hip.

BACKGROUND: Several mechanical derangements reportedly contribute to the development of noninflammatory arthritis of the hip. Diagnosis of these derangements involves the use of specific radiographic measures (eg, alpha angle, lateral center edge angle, cross-over sign). The reliability of some of these measures is not known, whereas others have not been confirmed. QUESTIONS/PURPOSES: We examined the reproducibility of 20 radiographic parameters of the hip used in clinical practice. METHODS: Twenty radiographic parameters on standardized digital AP and cross-table lateral radiographs were evaluated by two observers on two different occasions. The parameters were evaluated from the standpoint of reproducibility (reliability and agreement). The intraclass correlation coefficient (ICC), kappa coefficient, and standard error of measurement were calculated. The minimal detectable change was calculated where possible. RESULTS: Interrater reliability ranged from 0.45 to 0.90 for ICC depending on the measure. Intrarater reliability ranged from 0.55 to 0.99. Measurements that could be measured directly (femoral head diameter) were more reliable than measurements requiring estimation on the part of the observer (Tönnis angle, neck-shaft angle). Categorical parameters had interrater and intrarater reliability kappa values greater than 0.90 for all parameters measured. Agreement between repeated measurements, as given by the minimal detectable change, showed many parameters with low absolute reliability have clinical use in the context of the large changes seen in clinical practice. CONCLUSION: Radiographic hip measures show clinical utility when evaluated from the perspective of agreement and reliability. CLINICAL RELEVANCE: All measures investigated show clinical utility when evaluated from the perspective of reliability and agreement. LEVEL OF EVIDENCE: Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Potential contribution of femoroacetabular impingement to recurrent traumatic hip dislocation.

A 16-year-old boy sustained a traumatic posterior dislocation of the right hip. After initial closed reduction, the hip spontaneously redislocated within 2 days. Four days after the initial dislocation, the patient was transferred to the authors' institution, where a radiographic workup showed a severe capsular and labral disruption from the posterior aspect of the acetabulum. Subsequently, the patient underwent operative treatment using the technique of surgical hip dislocation through a digastric osteotomy as described by Ganz. Using this approach, the avulsed capsulolabral complex as well as the pathological head-neck junction, which is suspected to be a lever for the femoral head, could be fully addressed. The authors recommend further radiographic studies to evaluate the underlying pathology in traumatic dislocation of the hip as well as the described surgical approach, which leads to successful treatment of the entire pathology.

Revision total hip arthroplasty performed through the Hueter interval.

Revision total hip arthroplasty through the direct anterior approach is technically challenging but offers some advantages in exposure of the acetabulum. This study presents a retrospectively reviewed consecutive series of fifty-one patients who underwent revision total hip arthroplasty through the anterior approach utilizing various extensions of this technique. The anatomic approach is discussed as well as problems as encountered in our series.

Simultaneous bilateral supine anterior approach total hip arthroplasty: evaluation of early complications and short-term rehabilitation.

Simultaneous bilateral anterior approach total hip arthroplasty has been a successful procedure with high patient demand and good short-term clinical results. Complication rates are acceptable and compare favorably with previously published series. The anterior approach takes advantage of supine positioning, allowing improved intraoperative monitoring and anesthesia care. Short-term rehabilitation goals are met early with this technique. Despite these advantages, providing this simultaneous approach imposes a large financial burden on the hospital and surgeon.