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| IMC Wiki | Condylar neck fractures, treatment

Condylar neck fractures, treatment

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Indications for treatment

  • Clinical and/or radiological evidence of a fracture
  • Impaired occlusion
  • Functional disorders
  • Disturbed mandibular–maxillary relationship
  • Damage to the external auditory canal
  • Otorrhoea from the external auditory canal
  • Pain
Treatment of condylar fractures is controversial. A great many opinions and treatment options can be found in literature. Traditionally, these fractures have been treated using rigid or flexible intermaxillary fixation with subsequent physiotherapy. This is the treatment of choice for condylar neck fractures in children.
Numerous articles describe a satisfactory result achieved through a conservative (closed) treatment approach. Surgeons who prefer the closed treatment approach point out a reduced morbidity. Among the arguments for conservative treatment are the comparable clinical results, a simplified technique and avoidance of complications as a result of surgery. However, conservative treatment may give rise to sequelae, such as occlusal disorders, temporomandibular joint dysfunction, chin deviation, facial asymmetry and ankylosis.
Some indications for open reduction and internal fixation of extracapsular fractures in adults have been described (Schwimmer 1988) but there are but a few, probably due to the limited surgical accessability. A further limiting factor is the possible damage to neurovascular structures. Displacement of the proximal segment into the middle cranial fossa, lateral extra-articular displacement of the proximal segment, bilateral extracapsular fractures with occlusal disturbances as well as comminuted mandibular fractures associated with multiple craniofacial fractures with loss of vertical and transverse dimensions (Schimmer 1988, Zide and Kent 1983, Raveh et al. 1994) are absolute indications for open reduction.
In addition to those indications described there are numerous clinical situations where a definitive therapeutic approach based on sound scientific criteria does not exist.

Due to the improved options for surgery, there is a tendency towards open reduction. Indications for open reduction of condylar fractures have been extended (see below).
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Arguments for a surgical approach

Conservative treatment of adult patients resulted in a significant number of patients with post-operative functional disorders and limitations (Lindahl 1977, Zou et al. 1987, Oikarinen et al. 1991; Iuzuka et al. 1991).
Worsaae and Thorn (1994) described adult patients with extracapsular fractures managed conservatively having a higher frequency of complications than patients treated surgically using circumferential wiring. Complications included altered occlusion, mandibular asymmetry, impaired masticatory function, deficient healing of fractures or non-union of fractures, disk displacement, ankylosis and pain on the affected side. Neither the degree of dislocation of the proximal fragment nor a concomitant mandibular fracture or a absent posterior occlusion seemed to have an impact on the results (Worsaae and Thorn 1994).
Takenoshita et al. (1990) and Hidding et al. (1992) made a comparative study and came to the conclusion that supposedly good clinical results in the group with conservative treatment should not conceal the poor occlusal results observed from bite recordings and x-ray assessment. They emphasised that open reposition of dislocated condylar fractures resulted in excellent clinical and radiographic outcomes and recommend open reduction for the treatment of dislocated condylar neck fractures.
A retrospective study by Yang et al. (2002) compared functional results of unilateral condylar neck fractures treated either by surgery or conservatively. Patients treated with a conservative approach showed a significantly lower incidence of condylar pain and chin deviation than patients who had undergone surgery. Although subcondylar fractures were more complicated in the surgery group, there was no significant difference with regard to functional results of the two groups. However, the authors indicate the possible morbidity due to surgery as well as resulting longer periods of hospitalisation and higher costs.

Arguments for a conservative approach

In a retrospective study, Smets et al. (2003) recommend surgical reduction and rigid internal fixation only for patients with an ascending mandibular ramus shortened by more than 8mm and/or a significant displacement of the condylar fragment.
On the other hand, Iizuka et al. (1991) observed resorption of condylar fragments following mini-plate osteosynthesis, sometimes within 8 weeks following surgery. They determined that the risk of resorption and deviation are increased as a result of unsatisfactory reduction of the condylar fragment and rigid fixation in a non-physiological position, due to increased functional load.
Choi et al. (2001) evaluated the disk position following surgical treatment of unilateral condylar fractures using magnetic resonance imaging (MRI) and found that surgical repositioning will not always (20%) necessarily lead to anatomic normalisation of joint structures.

Parameters for the selection of treatment

Based on different post-treatment follow-ups, Kleinheinz et al. (1999) presented reliable clinical parameters for diagnosis.
The treatment method must be selected based on objective and reproducible criteria!
This was achieved using a mathematical model based on the trigonometric use of the hypothenuse formula.

The most disadvantageous consequence of extracapsular mandibular fractures seems to be the loss of vertical height of the ascending mandibular ramus possibly associated with pain, malocclusion, open bite and impaired masticatory function (Dahlström et al. 1989, Walker 1994).
In cases of longitudinal displacement with contraction but without transverse tilting of the proximal segment, the vertical shortening can be measured using X-rays. However, if the proximal segment has been tilted medially caused by the pull of the lateral pterygoid muscle, the estimation of vertical height is more of a problem.
A simplified mathematical model based on the hypothenuse rule was used in order to calculate the loss of vertical ramus height.

Mathematical model for the calculation of height loss in relation to the angle of dislocation

#pic# #pic#

Parameter:
- Height of the fracture line
- Cause of dislocation
- Extent of the loss of height
- Calculation of remaining height

Each fracture should be assessed based on objective criteria obtained through the analysis of quantitative changes of condylar fragments. Each extracapsular fracture can be analysed mathematically using the results of the analysis. The most important factors that are to be assessed first are the fracture height (high or low), the dislocation and the loss of vertical height (Dahlström et al. 1989).

Indications for surgery

One criterion used for choosing either conservative management or a surgical approach is the degree of dislocation of the proximal fragments - where this is 37 degrees or more, with the vertical regenerative potential unable to compensate for a vertical shortening of the ascending mandibular ramus of more than 4 mm.

Two questions characterise this problem:
  1. How strong is the vertical regenerative potential of the shortened fragment if a non-surgical approach is used in treatment?
  2. How strong is the tendency of a tilted fragment to go back to an erect position if a conservative approach is used in treatment?
    Average reduction of the angle between the fragments by 6 degrees and vertical regeneration of approximately 4 mm were observed in quantitative measurements of the remodelling process in patients not operated on. Such results depend on functional treatment. These prospective data were based on data obtained from adults and cannot be transferred to children (Kleinheinz et al. 1999).

Absolute indications

  • Central luxation
  • Intrusion of a foreign body
  • Fracture types II and IV (Spiessl/Schroll) with an interfragmental angle > 37°
  • Fracture types II and IV (Spiessl/Schroll) with longitudinal dislocation with contraction exceeding 4 mm

Relative indications

  • Bilateral fractures in the edentulous jaw
  • Medical indications prohibiting intermaxillary fixation
  • Fractures combined with unstable midface fractures
  • Reduction only of the major dentate fragment
  • Earliest possible mobilisation of the mandible in order to prevent ankylosis
Bony consolidation of the condylar fracture is only of minor importance.

Procedure

  1. Immobilisation of the mandible using dental splints (intermaxillary immobilisation).
    In edentulous patients, immobilisation following prosthodontic treatment is achieved using a head-chin cap and the patient's own dentures fixed to each other in order to re-establish the vertical height of the mandibular ramus.
  2. Functional treatment either with partial mobilisation or through provision of functional-prosthodontic appliances, depending on the extent of functional disorder. This should enable straight and adequate opening movement of the mouth.
Depending on the location of the fracture and dislocation of fragments, immobilisation and functional treatment are combined.

Indications for the conservative treatment of fractures

  • Condylar neck fractures in children
    In children, approximately up to the age of 12, remodelling in the condylar region frequently occurs (Gundlach et al. 1991). Therefore, a conservative functional treatment approach is still preferred as relatively good anatomical normalisation may be achieved without the necessity for surgical intervention.
    This is not equivalent to active reduction of the condyle (Röthler et al. 1996)
  • With high and undislocated condylar neck fractures
  • If medical and/or anaesthesiological contra-indications for surgical treatment of fratures exist

General rules

Any additional fractures of the mandible should be actively treated as intensive and early functional follow-up treatment is absolutely essential in all forms of treatment (Upton, 1991).
The aim of surgery is to obtain sufficient stability of the fracture in order to allow immediate function (Lindqvist and Iizuka 1999).
Surgery is usually performed within the first 5-8 days; a conservative treatment approach is used if treatment is initiated later.

Additional measures

Pain management
Drainage of wound infection
Antibiotic treatment, if required

Follow-up

Any intra-articular fracture requires a functional follow-up treatment regardless of the treatment approach used in order to prevent late sequelae such as arthrosis or ankylosis.

Risk factors

  • Degree of fracture dislocation
  • Haemorrhage
  • Number of fractures (multiple fractures, segment fractures)
  • Foreign bodies
  • Wound contamination
  • Insufficient blood supply to fragments and overlying soft tissue
  • Malocclusion present prior to the accident
  • Infection
  • Concomitant injury in the maxillofacial region
  • Pre-trauma complaints and/or disorder of the temporomandibular joint
  • Time elapsing before treatment of the fracture
  • Pre-trauma bone damage (metabolism, irradation)
  • Ankylosis
  • Pseudoarthrosis
  • Arthrosis
  • Change of shape and position of the disk
  • Facial deformity
  • Skeletal deformity
  • Functional disorder (limited inter-incisal distance or mandibular excursion)
  • Impaired occlusion and/or masticatory function
  • Chronic pain
  • Chronic infection
  • Chronic neurological functional disorder (motor function and/or sensory function)

Recommendation

The decision for hospital or outpatient treatment must be based on the condition of the individual patient.