A biomechanical study of conventional acetabular internal fracture fixation versus locking plate fixation

Background

Conventional internal fixation entails the use of an interfragmentary lag screw along with a plate. Not all acetabular fractures are amenable to the placement of an interfragmentary lag screw, and the fracture may be displaced during tightening of the interfragmentary lag screw. Locking plates are a possible solution. We sought to determine whether a locking plate construct can provide stability equivalent to that provided with a conventional construct for transverse acetabular fractures.

Methods

We used 5 paired fresh-frozen cadaveric acetabula. We fixed one side with the conventional technique and the other side with a locking plate. We subjected each fixation to a cyclic compressive force up to 500 cycles, followed by compressive force until failure. We monitored 3-dimensional motion of the fracture.

Results

The average fracture gap at 50 N compressive force after 500 loading cycles was 0.41 (standard deviation [SD] 0.49) mm for the conventional plate and lag screw construct compared with 0.76 (SD 0.62) mm for the locked plate construct (p = 0.46). The force to failure, as defined by 2 mm of fracture gap, was 848 (SD 805) N for the conventional plate and lag screw construct compared with 506 (SD 277) N for the locked plate fixation (p = 0.34).

Conclusion

The locking plate construct is as strong as the conventional plate plus interfragmentary lag screw construct for fixing transverse acetabular fractures. Locking plates may improve management of acetabular fractures by eliminating the need for placement of an interfragmentary lag screw. Furthermore, they may be helpful in revision hip arthroplasty in patients with pelvic discontinuity.     

Tip apex distance,hip screw placement,and neck shaft angle as potential risk factors for cut-out failure of hip screws after surgical treatment of intertrochanteric fractures

Purpose

To describe the quality of osteosynthesis after intertrochanteric fractures evaluation of tip apex distance (TAD) and position of the hip screw have been established. Furthermore, a slightly valgus fracture reduction has been suggested to reduce the risk of cut-out failure. However, uniform recommendations for optimal screw positioning and fracture reduction are still missing. The purpose of our study was to confirm potential risk factors for cut-out of hip screws of intertrochanteric fractures and to provide recommendations for practical clinical use.

Methods

A retrospective analysis of all patients with intertrochanteric fractures treated with a DHS or a gamma nail between January of 2007 and May of 2010 was performed at a level I trauma center.

Results

Two hundred thirty-five patients with intertrochanteric fractures after intra- and extramedullary stabilization were analyzed. A TAD of more than 25 mm was demonstrated to be the most important factor for cut-out in stable and unstable fractures. Fracture reduction with a valgus NSA of 5–10° was associated with a trend towards a lower rate of screw cut-out while an anterior placement of the screw (Parker’s ratio index of <40) significantly increased cut-out incidence.

Conclusions

According to our results, the TAD should not exceed 25 mm in stable (AO/OTA A1) as well as unstable (AO/OTA A2) fractures. An increased anterior hip screw placement should be avoided while fracture reduction with a slight valgus Neck Shaft seems favorable.     

Caput valgum associated with developmental dysplasia of the hip: management by transphyseal screw fixation

Purpose

A late finding of some hips treated for developmental dysplasia of the hip (DDH) is a growth disturbance of the lateral proximal femoral physis, which results in caput valgum and possibly osteoarthritis. Current treatment options include complete epiphysiodesis of the proximal femoral physis or a corrective proximal femoral osteotomy. Alternatively, a transphyseal screw through the inferomedial proximal femoral physis that preserves superolateral growth might improve this deformity.

Methods

This study evaluates the effect of such a transphyseal screw on both femoral and acetabular development in patients with caput valgum following open treatment of DDH. These patients were followed clinically and radiographically until skeletal maturity. Preoperative and postoperative radiographs were assessed, measuring the proximal femoral physeal orientation (PFPO), the head–shaft angle (HSA), Sharp’s angle and the center edge angle of Wiberg (CE angle).

Results

Thirteen hips of 11 consecutive patients were followed prospectively. The age at the time of transphyseal screw placement was between 5 and 14 years. The mean improvement of the PFPO and HSA was 14° (p < 0.01) and 11° (p < 0.001), respectively. The mean improvement of Sharp’s angle and CE angle was 4.7° (p < 0.01) and 5.8° (p < 0.02), respectively. Five patients underwent screw revision.

Conclusions

A transphyseal screw across the proximal femoral physis improved the proximal femur and acetabular geometry.     

Acetabular fracture types vary with different acetabular version

Purpose

Acetabular fractures typically occur in high energy trauma. Understanding of the various contributing biomechanical factors and trauma mechanisms is still limited. While several investigations figured out what role femoral position during impact plays in distinct fracture patterns, no data exists on the influence of acetabular version on the fracture type. Our study was carried out to clarify this issue.

Methods

Radiological data sets of 192 patients (145 male, 47 female, age 14–90 years) sustaining acetabular fractures were assessed retrospectively. The crossover ratio of the crossover sign and presence or absence of the posterior wall sign and ischial spine sign were used to determine acetabular retroversion on conventional radiographs. Acetabular version in the axial plane was measured on a computed tomography (CT) scan. Statistics were then performed to analyse the relationship between the acetabular fracture type according to the Letournel classification and acetabular version.

Results

A significant difference (p = 0.029) in acetabular version was found between fractures of the anterior [mean equatorial edge (EE) angle 19.93°] and posterior (mean EE angle 17.53°) acetabulum in the CT scan. No difference was shown on the measurements on conventional radiographs.

Conclusions

Acetabular version in the axial plane has an influence on the acetabular fracture pattern. While more anteverted acetabula were frequently associated with anterior fracture types according to the Letournel classification, retroversion of the acetabulum was associated with posterior fracture types.     

Are Custom Triflange Acetabular Components Effective for Reconstruction of Catastrophic Bone Loss?

Background

Although the introduction of ultraporous metals in the forms of acetabular components and augments has increased the orthopaedic surgeon’s ability to reconstruct severely compromised acetabuli, there remain some that cannot be managed readily using cups, augments, or cages. In such situations, allograft-prosthetic composites or custom acetabular components may be called for. However, few studies have reported on the results of these components.

Questions/purposes

The purposes of this study were to determine the (1) frequency of repeat revision, (2) complications and radiographic findings, and (3) Harris hip scores in patients who underwent complex acetabular revision surgery with custom acetabular components.

Methods

Between August 2003 and February 2012, 26 patients (28 hips) have undergone acetabular reconstruction with custom triflange components. During this time, the general indications for using these implants included (1) failed prior salvage reconstruction with cage or porous metal construct augments, (2) large contained defects with possible discontinuity, (3) known pelvic discontinuity, and (4) complex multiply surgically treated hips with insufficient bone stock to reconstruct using other means. This approach was used in a cohort of patients with Paprosky Type 3B acetabular defects, which represented 3% (30 of 955) of the acetabular revisions we performed during the study period. Minimum followup was 2 years (mean, 57 months; range, 28–108 months). Seven patients (eight hips) died during the study period, and three (11%) of these patients (four hips; 14%) were lost to followup before 2 years, leaving 23 patients (24 hips) with minimum 2-year followup. Sixteen patients were women. The mean age of the patients was 67 years (range, 47–85 years) and mean BMI was 28 kg/m² (range, 23–39 kg/m²). Revisions and complications were identified by chart review; hip scores were registered in our institution’s longitudinal database. Pre- and postoperative radiographs were analyzed by the patient’s surgeon to determine whether migration, fracture of fixation screws, or continued bone loss had occurred.

Results

There have been four subsequent surgical interventions: two failures secondary to sepsis, and one stem revision and one open reduction internal fixation for periprosthetic femoral fracture. There were two minor complications managed nonoperatively, but all of the components were noted to be well-fixed with no obvious migration or loosening observed on the most recent radiographs. Harris hip scores improved from a mean of 42 (SD, ± 16) before surgery to 65 (SD, ± 18) at latest followup (p < 0.001).

Conclusions

Custom acetabular triflange components represent yet another tool in the reconstructive surgeon’s armamentarium. These devices can be helpful in situations of catastrophic bone loss.

Level of Evidence

Level IV, therapeutic study.     

External fixation versus volar locking plate for displaced intra-articular distal radius fractures: a prospective randomized comparative study of the functional outcomes

Background

The objective of the study was to compare the efficacy of external fixation and volar plating on the functional parameter of displaced intra-articular (Cooney’s type IV) distal end radius fractures using the Green and O’Brien scoring system.

Materials and methods

This prospective randomized study comprised 68 patients treated with external fixation and 42 patients treated with volar locking plates. The patients were followed up at 6 months and 1 year after surgery. The assessment of pain, range of motion, grip strength and activity were assessed at each follow-up visit and scored according to the Green and O’Brien scoring system.

Results

At 1 year after surgery, we observed that external fixation showed significantly better results than volar locking plates using the Green and O’Brien scores for range of motion (22.0 ± 4.77 vs 19.89 ± 5.05), grip strength (19.91 ± 5.4 vs 16.89 ± 4.4) and final outcome (87.36 ± 11.62 vs 81.55 ± 11.32). No difference was found in pain and activity between these two groups of patients. Patients aged <50 years treated with external fixation showed excellent results (final score (91.57 ± 9.01) at 1 year follow-up.

Conclusion

External fixation showed superiority over volar locked plating after 1 year of surgery.

Level of evidence

IV.     

Does Cup-cage Reconstruction With Oversized Cups Provide Initial Stability in THA for Osteoporotic Acetabular Fractures?

Background

The incidence of acetabular fractures in osteoporotic patients is increasing. Immediate total hip arthroplasty (THA) has potential advantages, but achieving acetabular component stability is challenging and, at early followup, reported revision rates for loosening are high.

Questions/purposes

This study measured acetabular component stability and the initial surface contact achieved between the acetabular component and unfractured region of the pelvis after THA using an oversized acetabular component and cup-cage reconstruction.

Methods

Between November 2011 and November 2013, we treated 40 acute acetabular fractures in patients older than 70 years of age. Of these, 12 (30%) underwent immediate THA using an oversized acetabular component with screws inserted only into the ilium and a cup-cage construct. Postoperatively all patients were mobilized without weightbearing restrictions. Indications for immediate THA after acetabular fractures were displaced articular comminution deemed unreducible. Eleven of the 12 were prospectively studied to evaluate the initial stability of the reconstructions using radiostereometric analysis. One of the patients died of a pulmonary embolism after surgery, and the remaining 10 (median age, 81 years; range, 72–86 years) were studied. Of these, five were analyzed at 1 year and five were analyzed at 2 years. Acetabular component migration was defined as acceptable if less than the limits for primary THA that predict later loosening (1.76 mm of proximal migration and 2.53° of sagittal rotation). The contact surface between the acetabular component and ilium in direct continuity with the sacroiliac joint, and the ischium and pubis in direct continuity with the symphysis pubis, was measured on postoperative CT scans.

Results

At 1 year the median proximal migration was 0.83 mm (range, 0.09–5.13 mm) and sagittal rotation was 1.3° (range, 0.1°–7.4°). Three of the 10 components had migration above the suggested limits for primary THA at 1 year postoperatively. The contact surface achieved at surgery between the acetabular component and pelvis ranged from 11 to 17 cm² (15%–27% of each component).

Conclusions

The majority of acetabular components in this cohort were stable despite the small contact surface achieved between the component and pelvic bone. Three of 10 migrated in excess of the limits that predict later loosening in primary THA but it remains to be seen whether these limits apply to this selected group of frail osteoporotic patients. We continue to use this technique routinely to treat patients with the same indications, but since the analysis of these data we have added screw fixation of the acetabular component to the ischial tuberosity and the superior pubic ramus.

Level of Evidence

Level IV, therapeutic study.     

The acetabulum in Perthes’ disease: a prospective study of 123 children

Purpose

We assessed the radiographic changes of the acetabulum during the course of Perthes’ disease and investigated whether they were associated with femoral head sphericity 5 years after diagnosis.

Methods

We studied 123 children with unilateral Perthes’ disease, femoral head necrosis more than 50 % and age at diagnosis 6 years or older. Pelvic radiographs were taken at onset, 1 year and 5 years after diagnosis. Sharp’s angle, acetabular depth-to-width ratio (ADR) and lateral acetabular inclination were measured.

Results

Compared to the unaffected hips, the Perthes’ hips developed significantly higher Sharp’s angles (p < 0.001) and a higher proportion with an upward-sloping lateral acetabular margin (Perthes’ hips: 49 %, unaffected hips 1 %). The mean ADR values were significantly lower on the affected side at all stages (p < 0.001). ADR values at diagnosis were associated with a more spherical femoral head at the 5-year follow-up [odds ratio (OR) 1.012, 95 % confidence interval (CI) 1.002–1.022, p = 0.016]. None of the other acetabular parameters were significantly associated with the femoral head shape 5 years after diagnosis.

Conclusion

The acetabulum developed an increasingly dysplastic shape in the course of Perthes’ disease. Early dysplastic changes of the acetabulum were not associated with a poor radiological outcome 5 years after diagnosis. Routine measurement and monitoring of acetabular changes in plain radiographs were of little prognostic value and can, therefore, hardly be recommended in clinical practice.     

Acetabular fractures labelled poor surgical choices: Analysis of operative outcome

Purpose

We report the surgical outcome in 52 patients with acetabular otherwise considered as poor surgical choices.

Methods

43 male and 9 female patients were operated at a mean age of 43 years and followed up for a mean duration of 60.3 months. There were 22 elementary fractures and 31 associated ones according to Letournal and Judet classification. Osteosynthesis was attempted in 48 patients whereas a primary total hip arthroplasty was performed in 4 patients. Outcome was assessed radiologically and functionally employing Harris Hip Score (HHS).

Results

Average HHS in osteosynthesis group was 82.56 ± 12.4 with excellent to good results in 59.6% of the cases. Symptomatic osteoarthritis occurred in 13.5% of cases, avascular necrosis and severe heterotopic ossification in 7.7% each, infection and nerve palsy in 11.5% each.

Conclusion

Although the complication rates in this series is marginally more than that reported in literature, we recommend that the indications of surgical fixation in acetabular fractures need to be extended to those which were considered poor surgical choices.     

Long term results after surgical management of posterior wall acetabular fractures

Background

Posterior wall fractures are the most common of all acetabular fractures, and there is universal consensus that displaced fractures are best treated with anatomical reduction and stable internal fixation. Though early and mid term results for such studies are available, few shed light on long term results. This study was performed to evaluate long term functional and radiological outcomes in patients with posterior wall acetabular fractures and to determine factors that may contribute adversely to a satisfactory final outcome.

Materials and methods

We retrospectively analysed the hospital records for patients who underwent open reduction and internal fixation (ORIF) for posterior wall acetabular fractures. Twenty-five patients (20 men, five women), including one with bilateral posterior wall fracture, with a mean age of 41.28 ± 7.16 years (range 25–60 years) and a mean follow-up of 12.92 ± 6.36 years (range 5–22 years) who met the inclusion criteria formed the study cohort. Matta’s criteria were used to grade postoperative reduction and final radiological outcome. Functional outcome at final follow-up was assessed according to d’Aubigné and Postel score.

Results

Anatomic reduction was achieved in 22 hips, imperfect in four and poor in none. Radiological outcome at final follow-up revealed excellent results in ten hips, good in eight, fair in five and poor in three. The final d’Aubigné and Postel scores were excellent in 14 hips, good in six and fair and poor in three each. Patients with anatomical reduction had a favourable functional and radiological long term outcome. However, the presence of associated injuries in lower limbs and a body mass index (BMI) >25 adversely affected the final functional outcome. Osteonecrosis was seen in three patients, heterotopic ossification in two and Morel Lavallee lesion in one. One patient had postoperative sciatic nerve palsy, which recovered 6 weeks after surgery.

Conclusion

Anatomic postoperative reduction leads to optimal functional and radiological outcome on long term follow-up; however, the presence of associated lower-limb injuries and BMI >25 adversely affects a satisfactory final outcome in patients with posterior wall acetabular fractures.

Level of evidence

(Level 4) Retrospective case series.     

Double tension band osteosynthesis in transverse supracondylar distal humerus fractures and nonunions

Purpose

The purpose of this study was to evaluate the objective and subjective results achieved after double tension band fixation in transverse extra-articular intracapsular supracondylar distal humerus fractures and nonunions in adults.

Methods

Nine patients presenting six fractures and three nonunions of the distal humerus, treated with double tension band wiring between 1998 and 2011, were retrospectively evaluated. Two fractures were type A2 and four type A3, and the nonunions were oligotrophic; all nine lesions had a supracondylar intracapsular transverse orientation, that passed through the olecranon fossa, in a direction parallel to the joint line, and they compromised both columns of the distal humerus. Patient’s age averaged 70 years (range, 56–82).

Results

Follow-up averaged 24.6 months (range, 12–53). All fractures and nonunions united; there were no infections, elbow stiffness or heterotopic bone formations. DASH score at final follow-up averaged 14.2 points (range, 4–22). The analog scale of pain averaged 1.1 points (range, 0–3). Elbow range of motion averaged 100° (range, 100–120°). Flexion averaged 123° (range, 115–130°) and elbow extension loss averaged 15.5° (range, 10–25°).

Conclusions

The results achieved with double tension band fixation in transverse extra-articular intracapsular supracondylar distal humerus fractures and nonunions are comparable to the results that can be expected when using other available fixation methods; this technique is faster, less demanding and cheaper, and surgeons should have it in mind when leading with these particular types of distal humerus fractures and nonunions.     

Non-operative treatment versus percutaneous fixation for minimally displaced scaphoid waist fractures in high demand young manual workers

Background

Managing minimally displaced scaphoid fractures in young individuals doing physically demanding work remains an issue of debate due to duration of immobilisation and time required off work. Therefore, early diagnosis and appropriate treatment are important to avoid short- and long-term consequences. The literature lacks the exact definition of minimally displaced scaphoid waist fractures. The objective of this review article was to discuss nonoperative and minimally invasive treatment (percutaneous screw fixation) for minimally displaced scaphoid waist fractures and to systematically review the literature, focussing on young workers with physically demanding employment.

Materials and methods

We searched for articles through the most commonly used portals using appropriate terminologies to identify the most relevant articles in the English language comparing nonoperative and percutaneous fixation methods for these fractures in patients between 16 and 40 years of age. Strict inclusion and exclusion criteria were observed.

Results

Sixty relevant published articles were found. Twenty-one of these were considered valid for inclusion and comprised five randomised controlled trials, three prospective studies, four systematic reviews, three meta-analyses, and six retrospective studies. These studies provided a reasonable account of information on the managing undisplaced and minimally displaced scaphoid waist fractures, with satisfactory clinical and statistical analysis. However, it was difficult to assess the outcomes of minimally displaced fractures in isolation. Furthermore, few of these studies relied on plain radiographs for assessing union and did not report on patients’ work status.

Conclusion

Cast treatment has the disadvantages of longer immobilisation time, joint stiffness, reduced grip strength, and longer time to return to manual work. Percutaneous fixation is aimed at reducing damage to the blood supply and soft tissues, allowing early mobilisation of the wrist and early return to manual work. The best available evidence for percutaneous screw fixation versus cast treatment suggests that percutaneous fixation allows a faster time to union by 5 weeks and an earlier return to manual work by 7 weeks, with similar union rates. This systematic review indicates a potential requirement for a prospective randomised controlled trial to compare these two treatment modalities for minimally displaced scaphoid waist fractures in workers with physically demanding jobs in order to objectively assess functional outcomes, time to union and time to return to work.

Level of evidence

Level 3.     

Miniarthrotomy assisted percutaneous screw fixation for displaced medial malleolus fractures – A novel technique

Aim

To describe here a technique of miniarthrotomy assisted percutaneous screw insertion for displaced Herscovici type B and C medial malleolar fractures.

Method

Incision was made centred over the superomedial angle of the ankle mortise, about half a cm medial to tibialis anterior. Arthrotomy was done and reduction obtained. Percuntaneously, two 4 mm cancellous cannulated screws were inserted through medial malleolus.

Results and conclusion

This approach allows direct visualization of reduction, removal of entrapped soft tissue and preservation of saphenous vein and nerve.     

Intramedullary fixation of distal fibular fractures: a systematic review of clinical and functional outcomes

Background

Ankle fractures are extremely common and represent nearly one quarter of all lower-limb fractures. In the majority of patients, fractures involve the distal fibula. The current standard in treating unstable fractures is through open reduction and internal fixation (ORIF) with plates and screws. Due to concerns with potentially devastating wound complications, minimally invasive strategies such as intramedullary fixation have been introduced. This systematic review was performed to evaluate the clinical and functional outcomes of intramedullary fixation of distal fibular fractures using either compression screws or nails.

Materials and methods

Numerous databases (MEDLINE, PubMed, Embase, Google Scholar) were searched, 17 studies consisting of 1,008 patients with distal fibular fractures treated with intramedullary fixation were found.

Results

Mean rate of union was 98.5 %, with functional outcome reported as being good or excellent in up to 91.3 % of patients. Regarding unlocked intramedullary nailing, the mean rate of union was 100 %, with up to 92 % of patients reporting good or excellent functional outcomes. Considering locked intramedullary nailing, the mean rate of union was 98 %, with the majority of patients reporting good or excellent functional outcomes. The mean complication rate across studies was 10.3 %, with issues such as implant-related problems requiring metalwork removal, fibular shortening and metalwork failure predominating.

Conclusion

Overall, intramedullary fixation of unstable distal fibular fractures can give excellent results that are comparable with modern plating techniques. However, as yet, there is unconvincing evidence that it is superior to standard techniques with regards to clinical and functional outcome.

Level of evidence

Level IV evidence.     

Minimal invasive para-rectus approach for limited open reduction and percutaneous fixation of displaced acetabular fractures

Introduction

Minimal invasive fixation has been reported as an alternative option for treatment of acetabular fractures to avoid blood loss and complications of extensive approaches. Closed reduction and percutaneous lag screw fixation can be done in minimally displaced acetabular fractures. Open reduction is indicated, if there is wide displacement. In this study, we report the use of a mini-open anterior approach to manipulate and reduce anteriorly displaced transverse acetabular fractures combined with percutaneous lag screw fixation.

Methods

This report included eight patients. All had anterior displaced simple transverse acetabular fractures. An oblique mini-incision was made above and medial to the mid-inguinal point, and lateral to the lateral border of rectus abdominis muscle. The external abdominal oblique aponeurosis was incised along its fibres. The arched fibres of internal abdominal oblique were displaced medially above the inguinal ligament to expose and incise the fascia transversalis. Care was taken to avoid injury of ilioinguinal nerve, inferior epigastric vessels, and spermatic cord. The external iliac vessels were palpated and protected laterally. A blunt long bone impactor was introduced through this small incision to manipulate and reduce the fracture under fluoroscopic control. Fluoroscopic guided percutaneous lag screw fixation was done in all patients.

Results

The average time to operation was 4 days. Average blood loss was 110 mL. Operative time averaged 95 min. Maximum fracture displacement averaged 10 mm preoperatively and 1.3 mm postoperatively. According to Matta score, anatomical reduction of the fracture was achieved in five patients and imperfect in three. Follow up averaged 27 months. Wound healing occurred without complications and fracture union was achieved without secondary displacement in all patients. Average time to fracture healing was 14 weeks. According to the modified Merle d’Aubigné score, functional outcome was good to excellent in all patients.

Discussion and conclusion

Limited open reduction can solve the problem of fracture reduction, which is the main concern in minimal invasive fixation of acetabular fractures. It may help the inclusion of displaced acetabular fractures for percutaneous lag screw fixation. This mini-para-rectus approach has the advantages of minimal soft tissue dissection with the possible anatomical reduction of simple transverse displaced acetabular fractures.     

Acetabular roof arc angles and anatomic biomechanical superior acetabular weight bearing area

Background:

Acetabular fracture involves whether superior articular weight bearing area and stability of the hip are assessed by acetabular roof arc angles comprising medial, anterior and posterior. Many previous studies, based on clinical, biomechanics and anatomic superior articular surface of acetabulum showed different degrees of the angles. Anatomic biomechanical superior acetabular weight bearing area (ABSAWBA) of the femoral head can be identified as radiographic subchondral bone density at superior acetabular dome. The fracture passes through ABSAWBA creating traumatic hip arthritis. Therefore, acetabular roof arc angles of ABSAWBA were studied in order to find out that the most appropriate degrees of recommended acetabular roof arc angles in the previous studies had no ABSAWBA involvement.

Materials and Methods:

ABSAWBA of femoral head was identified 68 acetabular fractures and 13 isolated pelvic fractures without unstable pelvic ring injury were enrolled. Acetabular roof arc angle was measured on anteroposterior, obturator and iliac oblique view radiographs of normal contralateral acetabulum using programmatic automation controller digital system and measurement tools.

Results:

Average medial, anterior and posterior acetabular roof arc angles of the ABSAWBA of 94 normal acetabulum were 39.09 (7.41), 42.49 (8.15) and 55.26 (10.08) degrees, respectively.

Conclusions:

Less than 39°, 42° and 55° of medial, anterior and posterior acetabular roof arc angles involve ABSAWBA of the femoral head. Application of the study results showed that 45°, 45° and 62° from the previous studies are the most appropriate medial, anterior and posterior acetabular roof arc angles without involvement of the ABSAWBA respectively.     

One-screw fixation provides similar stability to that of two-screw fixation for type II dens fractures

Background

Anterior screw fixation has been widely adopted for the treatment of Type II dens fractures. However, there is still controversy regarding whether one- or two-screw fixation is more appropriate.

Questions/Purposes

We addressed three questions: (1) Do one- and two-screw fixation techniques differ regarding shear stiffness and rotational stiffness? (2) Can shear stiffness and rotational stiffness after screw fixation be restored to normal? (3) Does stiffness after screw fixation correlate with bone mineral density (BMD)?

Methods

We randomly assigned 14 fresh axes into two groups (seven axes each): one receiving one-screw fixation and another receiving two-screw fixation. Shear and torsional stiffness were measured using a nondestructive low-load test in six directions. A transverse osteotomy then was created at the base of the dens and fixed using one or two screws. Shear and torsional stiffness were tested again under the same testing conditions.

Results

Mean stiffness in all directions after screw fixation was similar in both groups. The stiffness after one- and two-screw fixation was not restored to normal: the mean shear stiffness restored ratio was less than 50% and the mean torsional stiffness restored ratio was less than 6% in both groups. BMD did not correlate with mean stiffness after screw fixation in both groups.

Conclusions

One- and two-screw fixation for Type II dens fractures provide similar stability but neither restores normal shear or torsional stiffness.

Clinical Relevance

One-screw fixation might be used as an alternative to two-screw fixation. Assumed BMD should not influence surgical decision making.     

Compression screw fixation without bone grafting for scaphoid fibrous nonunion

Purpose

Bone graft is often recommended as an adjuvant for treatment of scaphoid nonunions. However, recent literature has suggested that fibrous nonunion may be suited to treatment with rigid fixation without bone grafting. This work reported on outcomes of compression screw fixation for established scaphoid fibrous nonunions without bone graft.

Methods

Fourteen patients underwent surgical compression screw fixation without bone grafting of scaphoid fibrous nonunion between January 1, 2000, and December 31, 2012, with minimum follow-up until the time of clinical and radiographic healing. Fibrous nonunion of the scaphoid was defined as a scaphoid fracture with all of the following features: (1) persistent tenderness, (2) incomplete trabecular bridging on three X-ray views, (3) injury that had occurred at a minimum of 6 months prior to surgery, and (4) identification of fibrous union at the time of surgery. Outcomes were assessed with range of motion assessment, Disability of the Arm, Shoulder and Hand (DASH) scores, and plain radiographs.

Results

Twelve of the 14 patients healed successfully, while two patients required secondary vascularized bone grafting. Both unhealed patients sustained proximal pole fractures and had a duration of ≥1 year from injury to surgery. Average time to healing was 4.4 ± 2.0 months. Average flexion was 73 ± 22° and average extension was 66 ± 22° postoperatively. Average grip strength was 90 ± 25 lbs on the operative side. Mean postoperative pain score was 1.4 (range, 0 to 7). Mean postoperative DASH score was 10.2 (range, 0 to 52). Increasing age and an interval from injury to surgery of >1 year correlated with worse DASH and pain scores.

Conclusions

Patients with fibrous scaphoid nonunion demonstrated good results with rigid fixation without bone grafting. Increasing age and >1-year interval between injury and surgery resulted in lower self-assessed outcomes.

Level of Evidence

Therapeutic Level IV, retrospective case series