Twenty-Year Experience with Rigid Intramedullary Nailing of Femoral Shaft Fractures in Skeletally Immature Patients.

BACKGROUND: Debate exists over the safety of rigid intramedullary nailing of femoral shaft fractures in skeletally immature patients. The goal of this study was to describe functional outcomes and complication rates of rigid intramedullary nailing in pediatric patients. METHODS: A retrospective review was performed of femoral shaft fractures in skeletally immature patients treated with trochanteric rigid intramedullary nailing from 1987 to 2009. Radiographs made at initial injury, immediately postoperatively, and at the latest follow-up were reviewed. Patients were administered the Nonarthritic Hip Score and a survey. RESULTS: The study population of 241 patients with 246 fractures was primarily male (75%) with a mean age of 12.9 years (range, eight to seventeen years). The majority of fractures were closed (92%) and associated injuries were common (45%). The mean operative time was 119 minutes, and the mean estimated blood loss was 202 mL. The mean clinical follow-up time was 16.2 months (range, three to seventy-nine months), and there were ninety-three patients with a minimum two-year clinical and radiographic follow-up. An increase of articulotrochanteric distance of >5 mm was noted in 15.1% (fourteen of ninety-three patients) at a minimum two-year follow-up; however, clinically relevant growth disturbance was only observed in two patients (2.2%) with the development of asymptomatic coxa valga. There was no femoral head osteonecrosis. Among the 246 fractures, twenty-four complications (9.8%) occurred. At the time of the latest follow-up, 1.7% (four of 241 patients) reported pain. The average Nonarthritic Hip Score was 92.4 points (range, 51 to 100 points), and 100% of patients reported satisfaction with their treatment. CONCLUSIONS: Rigid intramedullary nailing is an effective technique for treatment of femoral shaft fractures in pediatric patients with an acceptable rate of complications. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Closed suction irrigation for the treatment of postoperative wound infections following posterior spinal fusion and instrumentation.

STUDY DESIGN: Retrospective review of clinical cases. OBJECTIVE: This study describes the success rate of closed suction irrigation system (CSIS) in the treatment of post operative spinal infections. SUMMARY OF BACKGROUND DATA: Given the widening use of spinal instrumentation, the management of related postoperative deep wound infections has become increasingly important. In the literature, there have been reports of several treatment methods yet no firmly established protocol for management of postoperative deep wound infections exists. The goal of this study was to determine the effectiveness of our protocol employing (CSIS) in the treatment of postoperative deep wound infections. METHODS: A retrospective record review of 500 posterior instrumented fusions between 1990 and 2002. Twenty-eight consecutive infections (5%) were diagnosed and treated by a standardized treatment protocol of Incision and Drainage, and CSIS. Cultures were obtained, wounds closed primarily, and appropriate intravenous antibiotic treatments initiated. For statistical evaluation, patients were assigned a risk factor (RF) described by Levi et al (J Neurosurg. 1997;86:975-980). Point values were assigned to medical comorbidities that may contribute to postoperative infection risk; higher RF values indicate an increased risk. RESULTS: Twenty-one acute and 7 late (>6 months) infections were followed for 22.3 months (1-86 months), post-CSIS treatment. Twenty-one (75%) resolved without recurrence with one CSIS treatment. Seven acute infections (25%) required a second course of treatment. Hospitalization for the index procedure averaged 15.4 days; 28.9 days for reinfections. No patient with an acute infection required implant removal. The reinfection group had higher blood loss, more levels fused, and longer hospitalization. The reinfection group was comprised entirely of pediatric patients. CONCLUSION: No correlation was found between RF values and greater risk of recurrent infection. Removal of implants is unnecessary in acute infections, provided the infection does not return. CSIS is an effective method for treatment of postoperative wound infections following instrumented spinal fusion avoiding the need for secondary closure.

Correlation of scoliosis curve correction with the number and type of fixation anchors.

STUDY DESIGN: Clinical and radiologic assessment derived from a prospective multicenter data base of adolescent idiopathic scoliosis (AIS) patients. OBJECTIVE: We investigated if "implant density" or the number of screws correlated with the major curve (thoracic or lumbar) correction at 2 years in patients with AIS. We also investigated the effect of implant density on the change in sagittal contour before surgery to after surgery. SUMMARY OF BACKGROUND DATA: Controversy exists regarding number and type of spinal anchors and the number of implant sites used that result in improved correction in AIS. METHODS: A prospective database of patients with AIS treated by posterior instrumentation between 1995 and 2004 was analyzed. The major curve correction expressed as % correction (from preoperative to 2 years postoperative) was correlated with the percentage of implants relative to the number of available implant sites within the measured Cobb angle. Correlation of % correction to the number of hooks, wires, and screws was also performed. We also analyzed the change in sagittal contour T2-T12, T5-T12, and T10-L2 before surgery and after surgery. This absolute change was then correlated with implant density, as was the number of hooks, wires, and screws. RESULTS: There were 292 patients included with all 6 Lenke curve types represented (250 with major thoracic curves and 42 with major lumbar curves). The overall % coronal Cobb correction was 64% (range: 11%-98%). The implant density within the major curve averaged 61% (range: 6%-100%). There was a significant correlation between implant density and % curve correction (r = 0.31, P < 0.001). The number of each implant type (hooks, wires, and screws) in the construct did not correlate with the % correction; however, the average % correction of the major curve was greater when the Cobb levels were instrumented only with screws (64%) compared to hooks alone (55%), P < 0.01. The greatest % correction 78% was achieved when bilateral segmental screws were used (100% screw density). The higher the implant density within the major thoracic curve, the greater the postoperative loss of kyphosis at T2-T12 (r = -0.13, P < 0.01) and T5-T12 (r = -0.16, P < 0.001). At T10-L2, increasing screw implant density correlated with decreasing kyphosis (r = -0.40, P < 0.001), whereas increasing hook implant density correlated with increasing kyphosis (r = 0.33, P < 0.001). CONCLUSION: Major curve correction at 2 years correlates most with the implant density that is correction increases with the number of implants used within the measured Cobb levels. Although the absolute number of screws used did not correlate with correction, there was an advantage in lumbar and thoracic curves to using screws compared to hooks. Sagittal contour in the thoracic spine became less kyphotic than the higher the implant density.

Biomechanical stability of single-screw versus two-screw fixation of an unstable slipped capital femoral epiphysis model: effect of screw position in the femoral neck.

PURPOSE: To biomechanically evaluate single screw and varying 2 screw fixations for an unstable slipped capital femoral epiphysis (SCFE) model using physiologically relevant loading. STUDY DESIGN: In vitro biomechanical study. METHODS: Twenty-four immature porcine proximal femurs were prepared to simulate a mild-to-moderate unstable SCFE. The femurs were randomized into 4 fixation groups: single screw, 2 screws horizontally placed, 2 screws vertically placed, and 2 oblique screws. Biomechanical testing determined maximum load to failure (N), load (N) at 2, 4, 6, and 8 mm of femoral head displacement, and stiffness (newtons per millimeter) for each group. RESULTS: No significant differences were found among the 3 different 2 screw configurations. The 2 screw constructs were 66% stiffer and 66% stronger than the single screw construct. In addition, whereas there was no difference at 2 mm of femoral head displacement, each subsequent displacement (4, 6, and 8 mm) demonstrated significantly higher failure loads when 2 screws were used for stabilization. CONCLUSIONS: Slipped capital femoral epiphysis stabilization with 2 screws leads to increased stability over single screw fixation; however, none of the 3 configurations/placement patterns of the 2 screw constructs seemed to be superior in fixation stability. CLINICAL RELEVANCE: These data support the use of a 2 screw construct in acute/unstable SCFE fixation. The biomechanical benefit of 2 screws needs to be considered in the face of greater potential for inadvertent penetration into the joint with an increased number of screws.

Biomechanical analysis of single screw fixation for slipped capital femoral epiphysis: are more threads across the physis necessary for stability?

PURPOSE: To evaluate single screw fixation stability, in the treatment of slipped capital femoral epiphysis, as a function of screw thread distribution across the physis. STUDY DESIGN: In vitro biomechanical study. METHODS: Thirty porcine proximal femurs were sectioned through the physeal line and stabilized with a cannulated 7.3-mm stainless steel AO screw. The distal 16 mm of each screw was threaded (5 threads). The femurs were randomized into 5 groups (1, 2, 3, 4, or 5 threads across the physis) and biomechanically tested to determine failure load (N) and stiffness (N/mm). RESULTS: Femurs with 2 or 3 threads across the physis had a significantly greater load to failure and stiffness compared with femurs with 1, 4, or 5 threads across the physis (P < 0.05). CONCLUSIONS: Thread distribution across the physis seems to be important. When using screws with a 16-mm thread, greatest strength and stiffness are achieved when 40%-60% of threads engage the epiphysis, with a significant decrease when greater than 80% of threads cross the physis. Too few threads in the epiphysis as well as too few in the metaphysis both lead to decreased stability. CLINICAL RELEVANCE: This study challenges the belief that compression across the physis maximizes slipped capital femoral epiphysis fixation stability. We recommend equal distribution of threads across the physis when using 16-mm thread screws, and we postulate that screws with a greater thread length (32 mm or fully threaded) would increase fixation stability even further. Optimizing purchase may decrease the incidence of slip progression, especially as the prevalence of obesity increases in the adolescent population.

Salter-Harris I and II fractures of the distal tibia: does mechanism of injury relate to premature physeal closure?

INTRODUCTION: The distal tibial physis is the second most commonly injured physis in long bones. Recent reports demonstrate a high rate of premature physeal closure (PPC) in Salter-Harris (SH) type I or II fractures of the distal tibia. METHODS: At our institution, 137 distal tibial SH type I or II fractures were treated from 1994 to 2002. Reviews were performed on all patients and 91 fractures met inclusion criteria. Patients were categorized according to treatment. RESULTS: We report a PPC rate of 39.6% in SH type I or II fractures of the distal tibial physis. We found a difference in PPC based on injury mechanism. The rate of PPC in patients with a supination-external-rotation-type injury was 35%, whereas patients with pronation-abduction-type injuries developed PPC in 54% of cases. Type of treatment may prevent PPC in some fractures. The most important determinant of PPC is the fracture displacement following reduction. DISCUSSION AND CONCLUSION: PPC is a common problem following SH type I or II fractures of the distal tibia. Operative treatment may decrease the frequency of PPC in some fractures. Regardless of treatment method, we recommend anatomic reduction to decrease the risk of PPC.

The reverse sural neurocutaneous flap for hindfoot and ankle coverage: experience and review of the literature.

Soft-tissue defects about the ankle are common in orthopedic surgery. The wounds usually involve exposed bone or hardware, making skin grafting a poor option. Free tissue transfer remains a mainstay of treatment. Recently, the reverse sural neurocutaneous flap has gained popularity. At our institution, 11 fasciocutaneous flaps have been performed for defects averaging 53cm2. All flaps achieved stable coverage. One patient required repeat skin grafting. Given its reliability, easy dissection, and outpatient capability, this flap should be considered for coverage in this region.

A simple, accurate method to confirm placement of intra-articular knee injection.

BACKGROUND: Intra-articular knee injections are routinely performed in clinical practice without documenting intra-articular placement. HYPOTHESIS: A small amount of air to an intra-articular knee injection produces an audible "squishing" sound with range of motion. STUDY DESIGN: Prospective nonrandomized clinical trial. METHODS: The study group (20 knees from 20 patients) received an intra-articular injection with a mixture of local anesthetic, corticosteroid, contrast dye, and 1 to 2 cc of air. The control group (10 knees from 5 patients) received extra-articular injections of a mixture of local anesthetic, contrast dye, and 2 cc of air. All knees were examined immediately after injection for a squishing sound with range of motion. Postinjection arthrographic radiographs were taken to verify the actual placement. RESULT: All study group knees and no control group knees had intra-articular contrast by radiograph. Clearly audible squishing sounds were heard in 17 of 20 study knees (sensitivity of 85%). Squishing sounds were audible in none of the control knees (specificity of 100%). CONCLUSION: Adding 1 to 2 cc of air to knee injections provides a no-cost, reliable, sensitive, and specific method of confirming accurate placement. CLINICAL RELEVANCE: This simple method is easily reproduced, can confirm accurate placement, and can eliminate extra-articular injection as the reason for clinical response failure.

Biomechanical superiority of plate fixation for proximal tibial osteotomy.

Proximal tibial osteotomies require secure and durable fixation to allow early range of motion; however, biomechanical data comparing commonly used fixation methods are lacking. The current study was done to quantify the dynamic biomechanical performance of blade staple fixation and plate fixation of simulated proximal tibial osteotomies. A 15 degrees proximal tibial osteotomy was done on each of 18 synthetic adult composite tibias. Blade staples were used as the means of fixation in nine tibias; plate fixation was used in the remaining nine tibias. The specimens were stressed cyclically in sinusoidal loading whose peak compression and tension loads imitate those measured during normal gait. Device performance was quantified by measuring displacement at the osteotomy site and the number of cycles to failure. Plate fixation had a greater fatigue life than staples (eight plates surviving past 200,000 cycles versus one blade staple) and showed a trend toward less displacement (0.69 mm versus 0.97 mm). Plate fixation of proximal tibial osteotomies offers better fixation and dynamic mechanical performance than blade staples.

Evaluation of calcium sulfate paste for augmentation of lumbar pedicle screw pullout strength.

BACKGROUND CONTEXT: Many authors have evaluated the components responsible for ultimate pullout strength of pedicle screws. In these studies, one important variable has been the screw fixation. Because pedicle screw fixation has increased in popularity over recent years, so has the need for augmentation in difficult situations. Polymethylmethacrylate (PMMA) has been established as the gold standard in terms of strength of fixation but has the potential for severe complications when applied in spine surgery. Calcium sulfate is an alternative to PMMA, because it lacks the exothermic reaction, is potentially osteoconductive and is resorbed by the body in 30 to 60 days. PURPOSE: To determine the strength of a new calcium sulfate cement in terms of pedicle screw augmentation. The purpose was to evaluate calcium sulfate versus PMMA in terms of pullout strength. PMMA was considered the gold standard in terms of strength for this experiment. STUDY DESIGN: Lumbar vertebrae implanted with pedicle screws were subjected to axial pullout tests. The force required to cause implant failure was measured and compared for three methods of fixation. OUTCOME MEASURES: Force to failure (Newtons) for each pedicle test was recorded and analyzed with results from similarly augmented pedicles. METHODS: Lumbar vertebrae were harvested from four cadavers and implanted with pedicle screws. These screws were either placed in native bone or augmented with either calcium sulfate paste or PMMA. In those pedicles that had augmentation, the material was permitted to set for a minimum of 24 hours. Axial pullout tests were then performed using an MTS (Materials Testing System Corporation, Minneapolis, MN) testing machine. The screws were pulled out over a distance of up to 6 mm at 0.25 mm/sec. This rate and distance ensured failure in each case. The load to failure was recorded for each pedicle. RESULTS: Calcium sulfate augmentation improved pedicle screw pullout strength significantly when compared with native bone (p=.0003). This represented an average increase of 167% over the native bone. Likewise, PMMA improved the pullout strength significantly over native bone (p<.0001) for an average increase of 199%. There were no significant differences between the calcium sulfate and PMMA augmentation (p=.0791), although the PMMA averaged 119% of the strength of calcium sulfate. CONCLUSIONS: Although PMMA is considered the gold standard in terms of fixation strength, its use around the spine has been limited because of concern over complications. The calcium sulfate bone paste tested in this study demonstrated strength similar to PMMA without the major risks to the spinal cord. In addition, the calcium sulfate paste allows for possible osteoconduction to aid in spinal fusion. Further study is needed to determine the applicability of this calcium sulfate paste in the clinical setting of spine surgery.