Outcome measurements following acetabular fractures should be standardized using established outcome scores.

The goal of treating acetabular fractures is the restoration of a pain-free range of motion (ROM) of the hip joint under full weight bearing. This goal is achieved by different operative but also nonoperative treatment options.

The outcome is influenced by different factors like quality of fracture osteosynthesis and restoration of the joint surface. Other contributors to overall outcome during the postoperative course are heterotopic ossifications, necrosis of the femoral head, or thromboembolic complications.

In order to evaluate the long-term prognosis after acetabular fractures, uniform follow-up examination criteria are important, allowing comparison of outcomes after different treatment modalities.

A distinction between clinical and radiological assessment parameters is made. The different parameters are partially based on scores and are especially focused on the hip joint. Additional outcome measurement tools are available, which analyze the overall health of patients in relation to a standard healthy population. Additionally, a correlation between long-term outcome and specific peritraumatic parameters is useful in order to analyze their influence on long-term results.

23.2 Clinical Assessment of the Hip Joint

The mean follow-up time between trauma and follow-up is commonly given in months. The clinical follow-up should be conducted by the use of a standardized evaluation form.

23.2.1 Clinical Follow-up Examination

The assessment of the clinical long-term outcome concerning hip joint function is carried out using different evaluation instruments.

These commonly used evaluation instruments can be grouped into functional outcome scores that are purely focused on the hip joint (e.g., Harris Hip Score, Merle d’Aubigné score), and into outcome scores, which are related to the general health (e.g., SF-36, SF-12, EuroQol) and are not specific to disease or injury.

Additionally, the following parameters should be evaluated as proposed by the follow-up concept of the German Multicenter Group Pelvis I (Arbeitsgemeinschaft Becken I).¹

Pain

Periarticular hip pain and hip joint pain is evaluated by the examiner (objective pain estimation) and subjectively by the patient (subjective pain estimation).

Objective pain is distinguished into none, slight, moderate, and severe pain (▶ Table 23.1). The subjective pain is discriminated as non- or insignificant pain (VAS < 10%), moderate pain (VAS 10–74%), and severe pain (VAS ≥ 75%).

Additionally, the pain localization is differentiated. A distinction is made between pain sensation in the region of the hip joint and the groin, the posterior pelvic ring (iliac crest, sacroiliac [SI] joint, sacrum, gluteal region), or the anterior pelvic ring region (symphysis and pubis). In case of pain sensation at the pelvic ring, an additional evaluation of a concomitant pelvic ring fracture was performed.

Range of Motion of the Hip Joint

The range of motion of the hip joint is documented starting with the neutral position. Additionally, patients with explicit limitations of ROM are encompassed. An explicit limitation of ROM is defined as flexion < 90 degrees, extension < 0 degrees, as well as abduction, adduction, external rotation, and internal rotation < 10 degrees.

Furthermore, the functionality of the abductor muscles is evaluated by use of the Trendelenburg sign (▶ Table 23.2).

Neurological Deficiencies

All fracture-related permanent neurological deficiencies are included and graded according to severity:

• 
  

  Grade 1: subjective nonrecognized dysfunction of sensitivity

  
  
• 
  

  Grade 2: subjective dysfunction of sensitivity without loss of protection awareness and/or nondisturbing motor dysfunction without functional impairment

  
  
• 
  

  Grade 3: dysfunction of sensitivity with loss of protection awareness and/or motor dysfunction with loss of function

23.2.2 Merle d’Aubigné Score

The Merle d’Aubigné score is the most commonly used clinical and functional outcome score to evaluate long-term results after acetabular fractures.^{2,​3,​4,​5,​6,​7,​8,​9,​10,​11,​12,​13,​14} This score, which was primarily developed to evaluate the functional outcome after total hip replacement, contains three categories: pain, range of motion, and ability of walking.¹⁵

Each of the categories uses a six-point scale, where lower numbers equate to poor outcomes and higher numbers equal better outcomes (▶ Table 23.3). Thus, the maximum value is 18 points (excellent result) and the minimum value is 3 points (worst clinical/functional result).

Following the overall score, a classification into four result categories was established:

• 
  

  18 points: excellent clinical outcome (no functional impairments)

  
  
• 
  

  15–17 points: good clinical outcome (mild functional impairments)

  
  
• 
  

  13–14 points: moderate clinical outcome (relevant functional impairments)

  
  
• 
  

  < 13 points: bad clinical outcome (significant functional impairments)

23.2.3 Harris Hip Score

Additionally, the Harris Hip Score¹⁶ is used in some long-term outcome studies following acetabular fractures.^17,​18 This score is a clinical and functional outcome score with mainly subjective items and some objective items. This score is widely accepted for outcome evaluation after total hip replacement. It is characterized by high validity and high reliability.

The maximum score is 100 points. Five items are evaluated (▶ Fig. 23.1):

• 
  

  Pain

  
  
• 
  

  Walking pattern

  
  
• 
  

  Activities of daily living

  
  
• 
  

  Malposition/contracture

  
  
• 
  

  Range of motion

  
  
  
  

  

  
  

  Fig. 23.1 Harris Hip Score (original) for evaluation of long-term results after acetabular fractures.

  
  

  (Reproduced from Tschauner C. Becken, Hüfte. In: Wirth CJ, Zichner L, eds. Orthopädie und orthopädische Chirurgie. Stuttgart: Thieme; 2004.)

Each of these items is assessed differently. The pain item includes 44% of the overall score and thus is relatively heavily weighted in this questionnaire. The achieved points of all five items are added up and divided into four categories (excellent outcome, good outcome, moderate outcome, bad outcome). The following values are categorized:

• 
  

  90–100 points: excellent outcome

  
  
• 
  

  80–89 points: good outcome

  
  
• 
  

  70–79 points: moderate outcome

  
  
• 
  

  < 70 points: bad outcome

23.3 Relevant Peritraumatic Parameters for Documentation

In order to correlate the results from the above-mentioned scores with individual injury-related parameters, certain factors potentially influencing the long-term outcome have to be documented during the peritraumatic course.

For example, an exact correlation between the initial quality of reduction and the development of secondary joint degeneration is often missing from long-term analyses. Often, it is only stated that after nonanatomical joint reconstruction the risk for degenerative joint alterations is increased. In order to analyze further factors that influence the long-term outcome, it can be useful to compare only exact fracture types or only anatomically reconstructed joints with regard to the influence of other parameters like presence of marginal impactions or additional injury to the femoral head.

The following parameters are recommended by the German Multicenter Study Group Pelvis I of the German Trauma Society. Outcome evaluation after acetabular fractures should include the following additional parameters.

23.3.1 Age and Gender

Patients’ ages should be reported in years in order to allow analysis of age-dependent results. Patients’ genders should be assessed as nominal scaled data.

23.3.2 Type of Accident

In general, it can be useful to distinguish different accident types. Thus, a correlation between type of accident and observed fracture pattern is possible.

Discrimination is performed between car accidents, truck accidents, motorcycle accidents, bicycle accidents and motor vehicle accidents injuring pedestrians, simple falls (in sense of tumbling), falls from height (by chance or suicidal), and other accidents. Additionally, high energy trauma (e.g., road traffic accidents and falls from height) can be summarized and compared to low-energy trauma. The types of accidents are usually evaluated on a nominal scale.

23.3.3 Injury Mechanism

General and specific injury mechanisms should be distinguished. General trauma mechanisms are divided into direct impact trauma and long-lasting force impact, such as, entrapment or rollover with alternating force impaction from different directions.

The specific trauma mechanisms are divided into anteroposterior (AP)-directed forces against the hip joint/pelvis, lateral force impacts, axial impactions, and complex force mechanisms, in which multiple force vectors act on the pelvis.

The trauma mechanisms are usually evaluated on a nominal scale.

23.3.4 Mode of Admission

The rate of primary and secondary admitted patients is determined.

23.3.5 Injury Severity

The evaluation of injury severity is conducted—classifying the general type of trauma—and allows for international comparability using the Injury Severity Score (ISS).

The type of trauma is differentiated between patients with isolated acetabular fractures and patients with combined acetabular and pelvic ring fractures. Typically, a wide range of variability exists in an accompanied pelvic ring fracture—the majority of analyses should consider isolated acetabular fractures.

In additional pelvic ring fractures, the classification should at least include the pelvic ring fracture type (A, B, C according to the AO classification).

In order to analyze the influence of accompanying injuries (e.g., multiple injuries, polytrauma), the additional injuries should be documented and the ISS should be determined.

23.3.6 Classification

Acetabular fractures should be classified according to Letournel.⁶

23.3.7 Additional Injuries

The type of additional injuries can influence the overall quality of health (e.g., SF-36, SF-12, EuroQol; see ▶ Table 23.5) and therefore can be an influencing factor regarding long-term outcome.

Additional injuries of the head (traumatic brain injury [TBI]), the chest, the abdomen, the spine, and the extremities can be analyzed according to established criteria. A detailed evaluation of additional injuries is only recommended for larger studies including more than 200 patients. In smaller patient groups, at least the general localization of additional injuries should be documented.

23.3.8 Radiological Diagnostics

A differentiation between conventional X-rays and multislice imaging has to be made. For radiological measurements the AP pelvis, Judet views (obturator oblique view [OOV] and iliac oblique view [IOV]), and Pennal views (pelvic inlet and pelvic outlet) can be considered. Multislice imaging CT scans with/without multidirectional reconstructions as well as three-dimensional (3D) reconstructions with/without subtraction of the femoral head are used.

23.3.9 Fracture Morphology and Fracture Characteristics¹

Depending on the fracture type, additional specific fracture parameters should be documented. These have been highlighted in the former chapters on fracture patterns.

In fractures with a transverse fracture component, the exact course of this fracture line (e.g., infratectal, juxtatectal, transtectal) should be evaluated. In acetabular fractures with a posterior wall fragment, the level of the posterior wall lesion (e.g., superior, dorsal, inferior) should be evaluated.

Accompanying dislocations of the femoral head are described according to the direction of dislocation. Directions of femoral head dislocations are distinguished between posterior, central, anterior, cranial, and dorsocranial dislocations. The timing of reduction is documented in hours after trauma. A distinction between reduction within 6 hours after trauma and after 6 hours can be drawn.

Additional fractures of the posterior wall of the acetabulum are noted on a nominal scale as these fractures are of prognostic relevance. Fractures of the posterior wall are classified into nondisplaced and displaced fractures.

The primary maximum displacement on the joint level is measured on a CT scan in millimeters. Displacements of less than 5 mm and more than 5 mm or other distinctions can be made.

For evaluation of the involvement of the weight-bearing roof fragment of the acetabulum, the roof arc according to Matta et al, is also determined¹⁹ (▶ Fig. 23.2).

Related posts:

Epidemiology Indications and Planning Associated Posterior Column and Posterior Wall Fractures Pure Transverse Fractures Approaches Radiological Diagnostics

Stay updated, free articles. Join our Telegram channel

Join