Radiographic Determinants of Early Failure After Posterior Wall Acetabular Fracture Fixation

Frequency and Characteristics of Posterior Labral Injuries in Operative Acetabular Fractures Treated Through a Posterior Approach: A Prospective Observational Study

OBJECTIVES

The association between labral injuries and acetabular fractures is unknown. This study aimed to identify the frequency and characteristics of labral injuries in operatively treated acetabular fractures that cannot be identified on preoperative imaging.

METHODS

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DESIGN

Prospective observational cohort.

SETTING

Level I trauma center.

PATIENT SELECTION CRITERIA

Adult patients with an acetabular fracture operatively treated through a posterior approach.

OUTCOME MEASURES AND COMPARISONS

The frequency and characteristics of labral injuries.

RESULTS

Fifty-three of 71 acetabular fractures (75%; 95% confidence interval, 63%-83%) demonstrated a labral injury visible via the posterior approach. Posterior labral injuries occurred in 89% of operative acetabular fracture patterns involving the posterior wall and most commonly represent a detachment of the posteroinferior labrum (n = 39, 75%). Fractures with a labral injury were more likely to have gluteus minimus damage (93% vs. 61%, P = 0.02), femoral head lesions (38% vs. 17%, P = 0.03), joint capsule detachment (60% vs. 33%, P = 0.05), and fracture patterns involving the posterior wall (89% vs. 50%, P = 0.05).

CONCLUSIONS

This study describes the high rate (89%) of posterior labral injuries in posterior wall fractures, the most common injury pattern being a detachment of the posteroinferior labrum. Labral injuries in acetabular fractures may have important clinical implications and this study is the first to identify the frequency and characteristics of these injuries. Further studies should assess the relationship between labral injuries, treatment strategies, and the progression to post-traumatic osteoarthritis.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Influence of associated femoral head fractures on surgical outcomes following osteosynthesis in posterior wall acetabular fractures

Background

To date, no study has compared the surgical outcomes between posterior wall acetabular fractures with and without associated femoral head fractures. Therefore, we evaluated whether an associated femoral head fracture increases the incidence of fracture sequelae, including post-traumatic osteoarthritis (PTOA) and osteonecrosis of the femoral head (ONFH), following osteosynthesis for posterior wall acetabular fractures.

Methods

This retrospective clinical study enrolled 183 patients who underwent osteosynthesis for posterior wall acetabular fractures between 2009 and 2019 at a level-1 trauma center. The incidence of PTOA, ONFH, and conversion to total hip arthroplasty (THA) was reviewed.

Results

The incidence of PTOA, ONFH, and conversion to THA following osteosynthesis were 20.2%, 15.9%, and 17.5%, respectively. The average time for conversion to THA was 18.76 ± 20.15 months (range, 1–82). The results for the comparison of patients with associated femoral head fractures and isolated posterior wall acetabular fractures were insignificant (PTOA: 27.3% vs. 15.7%, p = 0.13; ONFH: 18.2% vs. 14.3%, p = 0.58; conversion to THA: 20.4% vs. 15.7%, p = 0.52). Upon evaluating other variables, only marginal impaction negatively affected ONFH incidence (odds ratio: 2.90).

Conclusions

Our methods failed to demonstrate a significant difference in the rate of PTOA, ONFH, or conversion to THA in posterior wall acetabular fractures with and without an associated femoral head fracture. Beyond femoral head fractures, the marginal impaction of the acetabulum could have led to early sequelae.

Level of evidence

Level III

Morphological Characteristics of the Posterior Wall Associated with Complex Acetabular Fractures: A Radiological Study Using 3D Software and Fracture Mapping Technique

Background

The aim of the study was to compare the morphological distinctions of the posterior wall (PW) in different complex acetabular fractures using 3D software and fracture mapping technique and ultimately to provide for improved clinical treatment.

Methods

One hundred and fourteen patients with complex acetabular fracture associated with PW were recruited. All patients were divided into two groups according to the injury mechanism of the PW: Group A (both-column and PW) and Group B (including posterior column and PW; T shape and PW; and transverse and PW). Fracture mapping was generated on the intra- and extrasurface of a standard template. The radiological parameters including spatial displacement, articular surface area, articular range, marginal impaction, and multifragments of the two groups were compared.

Results

The spatial displacement, intra-/extra-articular surface area, and start and end point in Group A were 10.9 mm (IQR, 8.4-15.2), 8.2 ± 2.6 cm², 17.9 ± 5.3 cm², 0.8° (IQR, -6.0-16.2), and 107.5° (IQR, 97.2-116.9), respectively. The results in Group B were 30.4 mm (IQR, 16.8-48.7), 4.1 ± 2.0 cm², 10.6 ± 4.4 cm², 29.5° (IQR, 19.2-38.0), and 117.5° (IQR, 98.2-127.2), respectively. Marginal impaction was defined by Letournel et al. All the differences between two groups were significant (P < 0.05). The fracture map in Group A showed an “L”-shaped pattern and a “cusp” on the ilium, and the PW was located at 1/5 to 1/4 of the posterosuperior part of the acetabulum. The fracture maps in Group B were scattered and lacked consistency, and the PWs were confined to 1/10 to 1/8 of the posterior acetabulum.

Conclusions

Quantitative measurements and fracture mapping represented the differences in morphological characteristics of PWs associated with complex acetabular fractures.

Morphological Characteristics of Posterior Wall Fragments Associated with Acetabular Both-column Fracture

Treatment of both-column fractures with posterior wall involvement is still a controversial topic. This type of posterior wall fracture is different from isolated acetabular posterior wall fracture (AO/OTA62-A1). The aim of this study is to compare the morphology of the posterior wall fragments of these two fracture patterns using computed tomography (CT) scans. All measured data were compared, and the differences between the groups (acetabular both-column fractures with posterior wall involvement were included in group A, and acetabular isolated posterior wall fractures were included in group B) were significant (P ≤ 0.05), including the direction angle, displacement, articular surface-posterior cortex ratio and articular surface area of the fracture fragment. The intraclass correlation coefficient of the measurements included inter-observer (ICC = 0.860) and intra-observer (ICC = 0.853). The morphology of the posterior wall fragments associated with both-column fractures is significantly different from that in isolated acetabular posterior wall fractures, and the treatment of the posterior wall fragment involved in both-column fractures of the acetabulum should be different from that of isolated acetabular posterior wall fractures.

Risk Factors for Early Reoperation After Operative Treatment of Acetabular Fractures

OBJECTIVES

To identify the risk factors for early reoperation after operative fixation of acetabular fractures.

DESIGN

Retrospective evaluation.

SETTING

Level I Trauma Center.

PATIENTS

Seven hundred ninety-one patients with displaced acetabular fractures treated with open reduction and internal fixation (ORIF) from 2006 to 2015. Average follow-up was 52 weeks.

MAIN OUTCOME MEASURES

Early reoperation after acetabular ORIF, defined as secondary procedure for infection or revision within 3 years of initial operation.

RESULTS

Fifty-six (7%) patients underwent irrigation and debridement for infection and wound complications. Four associated risk factors identified were length of stay in the intensive care unit, pelvic embolization, operative time, and time delay between injury and surgical fixation. Sixty-two (8%) patients underwent early revision, including 45 conversions to total hip arthroplasty, 10 revision ORIF, 6 fixation device removals because of concern for joint penetration (2 acutely and 4 > 6 months after surgery), and 1 stabilization procedure. Three risk factors associated with early revision were hip dislocation, articular comminution, and concomitant femoral head or neck injury. Combined injuries to the pelvic ring and acetabulum, fracture pattern, marginal impaction, and body mass index had no significant effect on early revision surgery.

CONCLUSIONS

Risk factors for early reoperation after operative fixation of acetabular fractures differed based on the reason for return to the operating room. Infection was more likely to occur in patients who had prolonged stays in the intensive care unit, had prolonged operative times, were embolized, or experienced delay in time to fixation. Revision was more likely with hip dislocation, articular comminution, femoral head or neck fracture, and advancing age.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effects of the acetabular fracture index and other factors of posterior wall acetabular fracture on functional outcome

Objective To analyze the effects of the acetabular fracture index (AFI) and other factors on the functional outcome of patients with acetabular fractures involving the posterior wall. Methods Forty-eight patients who underwent surgery in our department were reviewed. According to the AFI, which indicates the percentage of remaining intact posterior acetabular arc, the patients were divided into Group A (AFI ≤ 25%, 11 patients), Group B (25% < AFI ≤ 50%, 23 patients), Group C (50% < AFI ≤ 75%, 7 patients), and Group D (75% < AFI ≤ 100%, 7 patients). The AFI was measured with a computed tomography picture archiving and communication system or calculated with the cosine theorem. A nonparametric test and ordinal regression were used to determine the role of the AFI and other factors on the functional outcome. Perioperative information, including demographic and fracture-related data, reduction quality, physical therapy duration, association with a lower limb fracture and avascular necrosis of the femoral head were prospectively gathered. Results The mean AFIs of A, B, C, and D groups were 14.3%, 35.9%, 59.5%, and 81.2%, respectively. No statistically significant differences were observed among the groups for demographic and fracture-related data. A better reduction quality (OR = 4.21, 95%CI 1.42 ∼ 12.43, χ2 = 6.781, P = 0.009) and a larger value of AFI (OR = 2.56, 95%CI 1.18 ∼ 5.55, χ2 = 5.648, P = 0.017) result in a higher functional score. The functional outcome of a physical therapy duration of more than 12 months (OR = 0.15, 95%CI 0.02 ∼ 0.90, χ2 = 4.324, P = 0.038) was better than that of less than 12 months. Lower limb fracture (OR = 0.13, 95%CI 0.02 ∼ 0.74, χ2 = 5.235, P = 0.022) and avascular necrosis of femoral head (OR = 0.02, 95%CI 0.00 ∼ 0.87, χ2 = 4.127, P = 0.042) were found to correlate with a lower functional score. Conclusion With a greater of AFI, the functional outcome score would be better. Other factors, including reduction quality, physical therapy duration, association with a lower limb fracture, and avascular necrosis of the femoral head, most likely also affect hip functional recovery.