Displaced acetabular fractures: indications for operative and nonoperative management

Surgical management of posterior hip dislocations associated with posterior wall acetabular fracture: a study with a minimum follow-up of 15 years

OBJECTIVES

To evaluate the long-term outcome after surgical management of posterior hip dislocations associated with posterior wall acetabular fracture and to depict prognostic factors that may affect surgical results.

DESIGN

Retrospective review.

SETTING

Level I trauma center.

PATIENTS AND METHODS

Between 1983 and 1991, 19 patients with traumatic posterior hip dislocation associated with posterior wall fracture of the acetabulum were retrospectively reviewed. The clinical criteria proposed by Merle d'Aubigne were used for the evaluation of the patient's clinical status. Matta's radiologic scoring system was used for the analysis of the radiologic data. The Brooker scoring system was used to assess the extent of heterotopic ossification after acetabular fracture surgery.

RESULTS

There were 17 male patients and two female. The age range at the time of injury was 16 to 54 years with a mean age of 36 years. Follow-up ranged from 15 to 23 years (mean, 18.5 years). At final follow-up, radiographic outcomes were excellent in six patients (31.58%), good in 11 (57.89%), and fair in two (10.53%) patients. The mean clinical score was 15, ranging from 9 to 18. Clinical outcome was excellent in 10 cases (52.63%), good in six cases (31.58%), and fair in three cases (15.79%). When an anatomic reduction was achieved intraoperatively, excellent or good radiographic and clinical results were shown in 100% and 87.50% of the patients, respectively.

CONCLUSION

The adequacy of surgical reduction will determine the long-term outcome of surgically managed posterior hip dislocations associated with posterior wall acetabular fracture.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Operative treatment of acetabular fractures in an older population through a limited ilioinguinal approach

OBJECTIVES

To compare treatment of acetabular fractures in elderly patients through a limited approach versus a standard ilioinguinal approach and assess changes in outcome and morbidity.

DESIGN

Retrospective cohort comparison analysis.

SETTING

Tertiary referral center.

PATIENTS/PARTICIPANTS

Between January 1992 and January 2006, 143 patients 55 years of age or older were treated for acetabular fractures. Of these, 41 were treated through either a traditional or limited ilioinguinal approach. Patients with unilateral surgeries and a minimum follow-up of 2 years were included.

INTERVENTION

Open reduction and internal fixation of acetabular fractures through a limited (lateral two windows) approach versus traditional three window ilioinguinal approach.

OUTCOME MEASURES

Radiographic assessment of healing, reduction quality, progression to arthritis and total hip arthroplasty, operative time, length of stay, complications, SF-36, Musculoskeletal Functional Assessment, and the Short Musculoskeletal Functional Assessment.

RESULTS

The two groups were equivalent in terms of preinjury comorbidities, mechanism of injury, type and severity of fracture pattern, time to surgery, length of hospitalization, and incidence of postoperative complications. The overall rate of secondary total hip arthroplasty was 26.8% and was equivalent between the two groups. Functional outcome scores were comparable. The use of the lateral two windows was associated with a significant reduction in both blood loss and operative time.

CONCLUSIONS

The limited ilioinguinal approach to certain fracture patterns commonly seen in the elderly was associated with a decreased blood loss and surgical time. Moreover, there was no negative impact on outcomes in our cohort. The benefits of decreased blood loss and shorter operative time have a potential positive impact on management of these injuries.

LEVEL OF EVIDENCE

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

Conservatively treated acetabular fractures: A retrospective analysis

BACKGROUND

There are a few studies reporting the long term outcome of conservatively treated acetabular fractures. The present study aims to evaluate the quality of reduction, and radiological and functional outcome in displaced acetabular fractures treated conservatively.

MATERIALS AND METHODS

Sixty-nine patients (55 men and 14 women) with 71 displaced acetabular fractures (mean age 38.6 years) managed conservatively were retrospectively evaluated. There were 11 posterior wall, 5 posterior column, 6 anterior column, 13 transverse, 2 posterior column with posterior wall, 9 transverse with posterior wall, 6 T-shaped, 1 anterior column with posterior hemi-transverse, and 18 both-column fractures. The follow-up radiographs were graded according to the criteria developed by Matta J. Functional outcome was assessed using Harris hip score and Merle d'Aubigne and Postel score at final followup. Average follow-up was 4.34 years (range 2-11 years).

RESULTS

Patients with congruent reduction (n=45) had good or excellent functional outcome. Radiologic outcome in incongruent reduction (n=26) was good or excellent in 6 and fair or poor in 20 hips. The functional outcome in patients with incongruent reduction was good or excellent in 16 and satisfactory or poor in 10 hips. Good to excellent radiologic and functional outcome was achieved in all patients with posterior wall fractures including four having more than 50% of broken wall. Good to excellent functional outcome was observed in 88.8% of both-column fractures with secondary congruence despite medial subluxation.

CONCLUSIONS

Nonoperative treatment of acetabular fractures can give good radiological and functional outcome in congruent reduction. Posterior wall fractures with a congruous joint without subluxation on computed tomography axial section, posterior column, anterior column, infratectal transverse or T-shaped, and both-column fractures may be managed conservatively. Small osteochondral fragments in the cotyloid fossa or non-weight-bearing part of the hip with a congruous joint do not seem to adversely affect the functional outcome. Displaced transverse fractures with "V" sign may require operative treatment.

PROSPECTIVE STUDY ON SEVENTY-SIX CASES OF FRACTURED ACETABULUM WITH SURGICAL TREATMENT

OBJECTIVE

To conduct a prospective study on unstable and incongruent fractures of the acetabulum, in comparison with the literature, covering the type of access, fixation materials, degree of reduction, type of fracture and results after surgery.

METHODS

The authors evaluated 76 patients with unstable and incongruent fracture of the acetabulum between January 1999 and December 2009. The Marvin Tile classification was used, and all cases were treated surgically using the technique recommended by the AO-ASIF group.

RESULTS

The radiological evaluation was done in accordance with the Ruesch criteria, and good, excellent or perfect results were obtained for 64 patients (84.2%). The clinical evaluation was done in accordance with the Harris criteria, and good or excellent results were obtained for 62 patients (81.6%). The complications were assessed and, in comparison with the literature, were shown to be compatible with previous reports even after the statistical analysis.

CONCLUSION

It was concluded that anatomical reduction and stable fixation are important for good results.

Can computed tomography predict hip stability in posterior wall acetabular fractures?

BACKGROUND

In a pilot study, two-dimensional (2-D) CT assessment of posterior wall fracture fragments predicted hip stability with small fracture fragments and instability for large fracture fragments.

QUESTIONS/PURPOSES

To confirm the previous findings, we determined whether there is sufficient observer consistency and accuracy to predict hip stability in posterior wall acetabular fractures for this CT assessment method and assessed its ease of clinical use.

METHODS

We selected 10 fractures having variable characteristics with known clinical outcome and created three study participant groups, based on level of training, for evaluation. Each observer reviewed the CT scans from the 10 fractures and applied the method in two separate sessions, the second after at least a 1-month washout period.

RESULTS

Participants reported subjective ease in using the method, averaging 5 minutes (range, 3-11 minutes) for each assessment. Intraobserver and interobserver reliability were both greater than 0.80 regardless of the level of experience. Although sensitivity was 90%, specificity was only 61% after comparison with examination under anesthesia (EUA). Inappropriate nonoperative treatment would have occurred in 6% of cases and inappropriate operative treatment in 16%.

CONCLUSIONS

This method for assessing hip instability is reliable, reproducible, and easy to learn and use. However, as a diagnostic tool in the clinical setting, it is useful only for fractures involving greater than 50% of the posterior wall owing to limited accuracy. For fractures less than 50%, EUA should be performed to determine hip stability.

Acetabular fracture reductions in the obese patient

OBJECTIVES

To evaluate the radiographic and computed tomographic reduction qualities after acetabular fracture repair in obese and nonobese patients.

DESIGN

Retrospective review.

SETTING

University medical center.

PATIENTS/PARTICIPANTS

Two hundred forty-two patients were treated with open reduction internal fixation for displaced acetabular fractures. The nonobese group (Group 1) consisted of 149 patients and the obese group (Group 2) had 93 patients. A nonmorbidly obese group (Group 3 = 221 patients) and a morbidly obese group (Group 4 = 21 patients) were also created from the same patient population.

INTERVENTION

Operative repair of acetabular fractures.

MAIN OUTCOME MEASUREMENTS

Reductions on postoperative radiographs were classified as anatomic with less than 1 mm, imperfect with 2 to 3 mm, and poor with greater than 3 mm of residual displacement. On postoperative computed tomographic scans, reductions were considered nonanatomic with persistent gap or step displacements greater than or equal to 2 mm.

RESULTS

Anatomic radiographic reductions were achieved in 72% of the nonobese patients, 70% of the obese patients, 72% of the nonmorbidly obese patients, and 61% of the morbidly obese patients. (P = 0.379) On postoperative computed tomographic scans, an acceptable reduction was obtained in 47% of the nonobese patients, 44% of the obese patients, 47% of the nonmorbidly obese patients, and 31% of the morbidly obese patients. (P = 0.232).

CONCLUSIONS

Anatomic or satisfactory reductions can be similarly achieved in all classes of nonmorbidly obese patients who have sustained displaced acetabular fractures. In the morbidly obese, anatomic reductions may be more difficult to obtain.

Outcomes of posterior wall fractures of the acetabulum treated nonoperatively after diagnostic screening with dynamic stress examination under anesthesia

BACKGROUND

Dynamic stress fluoroscopy with the patient under general anesthesia has been advocated as a clinical measure of hip stability and congruity in patients with a posterior wall acetabular fracture. The purpose of this study was to establish the predictive value of the dynamic stress fluoroscopic examination for these fractures by evaluating clinical and radiographic outcomes after nonoperative treatment of fractures found to be stable with this examination.

METHODS

Twenty-one consecutive patients with an acute posterior wall fracture of the acetabulum who were shown to have a stable hip joint by dynamic stress fluoroscopy while they were under general anesthesia were treated nonoperatively. At the time of follow-up, the patients underwent clinical and/or radiographic evaluation.

RESULTS

Clinical follow-up was performed for eighteen patients at a minimum of two years after injury, at which time the average modified Merle d'Aubigné score was very good, with no one having less than a good clinical outcome. Fifteen of these eighteen patients had radiographic evaluation at a minimum of two years, and all were found to have a congruent joint with a normal joint space and no evidence of posttraumatic arthritis.

CONCLUSIONS

Hip joint stability determined with dynamic stress fluoroscopy with the patient under general anesthesia after a posterior wall acetabular fracture is predictive of hip joint congruity, an excellent radiographic outcome, and a good-to-excellent early clinical outcome after nonoperative treatment.

Treatment of acetabular fractures in an older population

OBJECTIVE

To identify factors predicting poor radiographic and functional outcome and delayed total hip arthroplasty in operatively managed acetabular fractures in patients 55 years of age and older.

DESIGN

Retrospective chart and radiographic review of a prospectively maintained database.

SETTING

Tertiary care hospital.

PATIENTS

Ninety-three with a mean age of 67 years met all inclusion criteria and had follow up averaging 5 years.

INTERVENTION

Open reduction and internal fixation and less commonly acute total hip arthroplasty for displaced acetabular fractures in an older cohort.

MAIN OUTCOME MEASUREMENT

Three validated patient self-assessment measures were used: the Musculoskeletal Functional Assessment, the Short Musculoskeletal Functional Assessment, and the SF-36.

RESULTS

The overall rate of hip replacement in our study was 30.95%. Poor fracture reduction (P < 0.02), development of avascular necrosis (P < 0.001), and previous contralateral hip arthroplasty (P = 0.02) were statistically associated with the need for secondary surgeries. Functional outcome scores in the current study compared favorably with functional outcome scores reported for acetabular fractures in younger populations and with age-matched "non-injured" norms published in recent literature.

CONCLUSIONS

There was an acceptably low rate of major complications in 93 operatively managed fractures in this population. Nearly 70% of patients achieved functional outcomes similar to age- and injury-matched control subjects without the need for secondary surgeries. Thirty percent of patients required secondary total hip arthroplasty for posttraumatic arthritis. These patients achieved outcomes similar to patients in the other outcome groups and to injury- and age-matched norms.

Biomechanical study of posterior wall acetabular fracture fixation using acetabular tridimensional memory alloy-fixation system

BACKGROUND

We developed the acetabular tridimensional memory alloy-fixation system (ATMFS), which is made of NiTi shape memory alloy, according to the specific mechanical properties of biological memory material, nitinol alloy and measured distribution of contact area and pressure between the acetabulum and the femoral head of cadaveric pelvis.

METHODS

Six formalin-preserved cadaveric pelvis were used for this investigation. Pressure-sensitive film was used to measure contact area and pressure within the anterior, superior, and posterior regions of the acetabulum. The pelvis were loaded under the following four conditions: (1) intact; (2) following a creation posterior wall fracture defect; (3) following reduction and standard internal fixation with reconstruction plate; (4) following reduction and internal fixation with a new shape memory alloy device named ATMFS. A posterior wall fracture was created along an arc of 40-90 degrees about the acetabular rim.

FINDINGS

Creation of a posterior wall defect resulted in increased load in the superior acetabulum (1422N) as compared to the intact condition (762N, P=0.007). Following reduction and internal fixation, the load distributed to the superior acetabulum (1486N) was not statistically different from the defect condition. Following the fixation with ATMFS, the load seen at the superior region of the actabulum (936N) was less than fixation with reconstruction plate and was not different from intact state (P=0.4).

INTERPRETATION

These data indicate that the use of ATMFS as a fracture internal fixation device resulted a partial restoration of joint loading parameters toward the intact state. ATMFS fixation may result in a clinical benefit.

Evaluation of computed tomography for determining the diagnosis of acetabular fractures

OBJECTIVE

We assessed whether, in contrast to reports in the literature, computed tomographic (CT) scans improve the ability to classify acetabular fractures in comparison with plain radiographs.

DESIGN

Prospective.

SETTING

Level I trauma center.

PATIENTS

Seventy-five patients with 75 acetabular fractures treated between June 2005 and May 2006.

INTERVENTION

Four different image sets for each patient were evaluated: image set A, Judet view plain radiographs plus axial view CT scans; image set B, Judet view plain radiographs alone; image set C, three-dimensional CT reconstructions; and image set D, CT-simulated anteroposterior and Judet views of the pelvis. The 300 image sets were viewed in random order by four orthopaedic trauma fellowship-trained surgeons who independently recorded a diagnosis. A gold standard diagnosis was determined by group consensus.

MAIN OUTCOME MEASUREMENTS

Agreement among four imaging methods was evaluated by using kappa statistics for multiple raters and nominal data.

RESULTS

Comparing the gold standard diagnosis with the four image sets, Judet view plain radiographs had a worse kappa value than CT scans (P < 0.05). The adjusted kappa values for all three image sets that included CT scans averaged greater than 0.62, showing substantial agreement, whereas the image set with plain radiographs alone (image set B) had a lower kappa value of only 0.48 (P < 0.05).

CONCLUSIONS

In contrast to previous reports in the literature, the accuracy of plain radiographs alone was less than the accuracy of CT scans in terms of diagnosis. The interobserver reliability was also worse for plain radiographs alone.

The radiological evaluation of acetabular fractures in the elderly

We have examined the accuracy of reduction and the functional outcomes in elderly patients with surgically treated acetabular fractures, based on assessment of plain radiographs and CT scans. There were 45 patients with such a fracture with a mean age of 67 years (59 to 82) at the time of surgery. All patients completed SF-36 questionnaires to determine the functional outcome at a mean follow-up of 72.4 months (24 to 188). All had radiographs and a CT scan within one week of surgery. The reduction was categorised as 'anatomical', 'imperfect', or 'poor'. Radiographs classified 26 patients (58%) as anatomical,13 (29%) as imperfect and six (13%) as poor. The maximum displacement on CT showed none as anatomical, 23 (51%) as imperfect and 22 (49%) as poor, but this was not always at the weight-bearing dome. SF-36 scores showed functional outcomes comparable with those of the general elderly population, with no correlation with the radiological reduction. Perfect anatomical reduction is not necessary to attain a good functional outcome in acetabular fractures in the elderly.

Factors determining quality of life and level of sporting activity after internal fixation of an isolated acetabular fracture

We investigated whether patients who underwent internal fixation for an isolated acetabular fracture were able to return to their previous sporting activities. We studied 52 consecutive patients with an isolated acetabular fracture who were operated on between January 2001 and December 2002. Their demographic details, fracture type, rehabilitation regime, outcome and complications were documented prospectively as was their level and frequency of participation in sport both before and after surgery. Quality of life was measured using the EuroQol-5D health outcome tool (EQ-5D). There was a significant reduction in level of activity, frequency of participation in sport (both p < 0.001) and EQ-5D scores in patients of all age groups compared to a normal English population (p = 0.001). A total of 22 (42%) were able to return to their previous level of activities: 35 (67%) were able to take part in sport at some level. Of all the parameters analysed, the Matta radiological follow-up criteria were the single best predictor for resumption of sporting activity and frequency of participation.

Sciatic nerve injury associated with acetabular fractures

Sciatic nerve injuries associated with acetabular fractures may be a result of the initial trauma or injury at the time of surgical reconstruction. Patients may present with a broad range of symptoms ranging from radiculopathy to foot drop. There are several posttraumatic, perioperative, and postoperative causes for sciatic nerve palsy including fracture-dislocation of the hip joint, excessive tension or inappropriate placement of retractors, instrument- or implant-related complications, heterotopic ossification, hematoma, and scarring. Natural history studies suggest that nerve recovery depends on several factors. Prevention requires attention to intraoperative limb positioning, retractor placement, and instrumentation. Somatosensory evoked potentials and spontaneous electromyography may help minimize iatrogenic nerve injury. Heterotopic ossification prophylaxis can help reduce delayed sciatic nerve entrapment. Reports on sciatic nerve decompression are not uniformly consistent but appear to have better outcomes for sensory than motor neuropathy.

Computed tomography as a predictor of hip stability status in posterior wall fractures of the acetabulum

OBJECTIVES

Studies using 2-dimensional computed tomography-derived criteria indicate that, in general, posterior wall fractures involving less than 20% of the posterior wall are stable and able to withstand physiologic loads, whereas those involving greater than 40%-50% are unstable, leaving a wide range of posterior wall fractures classified as indeterminate. The purpose of this study was to assess the ability of static measurement of posterior acetabular wall fragment size using computed tomography to predict hip stability status, as determined by dynamic stress examination under anesthesia.

DESIGN

Diagnostic level I. Retrospective analysis with testing of previously developed diagnostic criteria in a series of consecutive patients (with universally applied reference "gold" standard).

SETTING

Level I trauma center.

PATIENTS

Thirty-three consecutive patients with isolated unilateral posterior wall (OTA 62-A1) acetabular fractures were evaluated by dynamic fluoroscopic stress testing under general anesthesia (examination under anesthesia) to determine hip stability status and subsequent clinical treatment.

INTERVENTION

Three methods were used in a blinded fashion to calculate posterior wall fracture fragment size using 2-dimensional computed tomograms. These methods include those previously described by Calkins et al, which measures the smallest amount of intact acetabular arc, and Keith et al, which measures fragment size at the level of the fovea, and an alternative modification of that of Keith et al using the level of largest posterior wall deficit. Each method classifies hip instability into 3 groups: (1) stable, (2) indeterminate, and (3) unstable. The examination under anesthesia served as the gold standard.

MAIN OUTCOME MEASUREMENT

Examination under anesthesia

RESULTS

Examination under anesthesia determined 15 hips to be unstable and 18 hips to be stable. The analyses showed that the methods of Calkins et al and Keith et al had a substantial percentage of incorrect predictions, especially in the critical group 1 patients (those predicted to be stable but were actually unstable). The percent incorrectly predicted for these group 1 patients was 33.3% (positive predictive value 66.7%) for the data derived form Calkins et al and 14.3% (positive predictive value 85.7%) for the data derived form Keith et al. In contradistinction, for the alternative method, specificity, sensitivity, and positive predictive value were all 100% with a 0% incorrectly predicted. However, with this alternative method, there was an increase in the number of group 2 fractures (23), as compared with the group 2 numbers for Calkins et al (n = 7) and Keith et al (n = 18). Reanalysis of the data for better potential cut points indicated that none of the methods could be improved in this way.

CONCLUSIONS

The alternative method is the only reliable technique that is predictive of hip stability for small fracture fragments while also being predictive of instability for large fracture fragments. However, these findings are based on small patient numbers, and there remain a substantial number of fractures involving 20% or more of the posterior wall that are both stable and unstable by examination under anesthesia. Therefore, given the low risk of the stress examination and the inherent problems making the computed tomography measurements, dynamic fluoroscopic stress testing under general anesthesia should be the preferred method for the determination of hip stability status after posterior wall fractures of the acetabulum.

Impact of timing of pelvic fixation on functional outcome

Pelvic fractures are the third most common cause of death in motor vehicle accidents. Recent improvements in mortality can be attributed to the progress made in modern critical care medicine, multidetector CT, ATLS principles, multidisciplinary protocols and early fracture stabilisation. Currently, the timing of pelvic fixation is often based on the haemodynamic status and response of the patient to resuscitation, the fracture pattern, the presence of associated injuries and the immuno-inflammatory status of the patient. The purpose of this review is to focus on the impact of timing of reconstruction of pelvic fractures on the functional outcome of the patients. Thirty seven scientific studies on the outcome of pelvic and acetabular injuries were reviewed. Four on pelvic ring fractures, and one study on pelvic and acetabular fractures met our second inclusion criterion of prospective or retrospective studies investigating the outcome after early or late pelvic and acetabular fixation. These five studies suggested early pelvic and acetabular fixation for optimal outcome but their main difference was the definition of the length in time of that early period. In polytrauma patients, the "damage control orthopaedics" principle should be applied for haemodynamic and skeletal stabilisation (and faecal diversion, if indicated in cases of open fractures of the pelvis). The definitive fixation should be performed after the fourth post-injury day, when the physiological state of the patient is conducive to surgery.

Determinants of functional outcome after simple and complex acetabular fractures involving the posterior wall

We have evaluated the functional, clinical and radiological outcome of patients with simple and complex acetabular fractures involving the posterior wall, and identified factors associated with an adverse outcome. We reviewed 128 patients treated operatively for a fracture involving the posterior wall of the acetabulum between 1982 and 1999. The Musculoskeletal Functional Assessment and Short-Form 36 scores, the presence of radiological arthritis and complications were assessed as a function of injury, treatment and clinical variables. The patients had profound functional deficits compared with the normal population. Anatomical reduction alone was not sufficient to restore function. The fracture pattern, marginal impaction and residual displacement of > 2 mm were associated with the development of arthritis, which related to poor function and the need for hip replacement. It may be appropriate to consider immediate total hip replacement for patients aged > 50 years with marginal impaction and comminution of the wall, since 7 of 13 (54%) of these required early hip replacement.

The "Gull Sign": a harbinger of failure for internal fixation of geriatric acetabular fractures

OBJECTIVES

To identify factors affecting the outcomes of surgery for acetabular fracture in patients over the age of 60 years.

DESIGN

Retrospective review of records and radiographs; current examination, radiographs and outcome surveys when possible.

SETTING

Academic, Level 1 trauma center.

PATIENTS/PARTICIPANTS

Forty-eight patients over age 60 with displaced acetabulum fractures.

INTERVENTION

Surgical reduction and fixation.

MAIN OUTCOME MEASUREMENTS

Clinical ratings and radiographic evaluations, Short Musculoskeletal Functional Assessment survey (SMFA), SF-36, and hip-specific questions. Radiographs were evaluated using the criteria of Matta.

RESULTS

Ten patients died since surgery. Four were lost to follow-up. Seven had >12 months of follow-up information in the chart. Twenty-seven had current evaluations for the study. Average follow-up was 37 months, range 1-114 months. The average age at surgery was 71.6 years (range 61-88). No perioperative deaths occurred. Initial reductions achieved: 61% anatomic, 34% imperfect, and 5% poor. A specific radiographic finding (superomedial dome impaction) predictive of failure was identified. This was designated the "Gull Sign." These patients had inadequate reduction, early fixation failure, or medial/superior joint narrowing and subluxation. Functional outcomes in patients with current examination were similar to age-matched controls. Radiographic outcomes: 30% excellent, 30% good, 9% fair, 23% poor, and 7% arthroplasty. Anatomic reduction was closely related to good or excellent radiographic result.

CONCLUSIONS

While some patients over sixty years of age can have satisfactory functional outcomes after acetabular fracture fixation, a significant number will have failure of the procedure. Osteopenic patients with superomedial dome impaction (the Gull Sign) did not benefit from attempted open reduction and internal fixation in this series.