The modified Gibson approach to the acetabulum.

OBJECTIVE: Providing a surgical approach similar to the Kocher-Langenbeck but having improved anterosuperior access, less risk of injury to branches of the inferior gluteal nerve supplying the anterior portion of the gluteus maximus muscle, and improved cosmesis. INDICATIONS: Any surgery that would otherwise call for the Kocher-Langenbeck approach. CONTRAINDICATIONS: Fractures of the anterior column and/or wall; transtectal T-shaped fractures. Transverse fractures and infra/juxtatectal T-shaped fractures having the major displacement anteriorly at the pelvic brim with only minor posterior displacement. SURGICAL TECHNIQUE: Exposure of the acetabulum fracture through a straight skin incision, developing the plane between the anterior border of the gluteus maximus muscle and the tensor fasciae latae. The gluteus maximus is reflected posteriorly to reveal the underlying deep anatomic structures. POSTOPERATIVE MANAGEMENT: Thromboprophylaxis and prophylaxis as indicated for the prevention of heterotopic ossification are instituted. The patient is mobilized as quickly as the associated injuries will allow. Toe-touch weight-bearing is continued for 10-12 weeks. However, progression to full weight-bearing should be individualized. RESULTS: Between 1996 and 2000, 16 patients having a fracture of the acetabulum were operated on through the modified Gibson approach with 15 patients followed up for 1 year or more. Fracture types were posterior wall in eight patients, transverse in one, posterior column and wall in two, transverse and posterior wall in four, and T-shaped in one. There were no intraoperative or immediate postoperative complications. Clinical outcome was determined using a modification of the method developed by Merle d'Aubigné and Postel and was good-to-excellent in 14 patients and poor in one (a patient who developed osteonecrosis of the femoral head unrelated to the approach).

A finite element model of electrode placement during stimulus evoked electromyographic monitoring of iliosacral screw insertion.

Pelvic ring fractures that occur as a result of substantial orthopedic trauma are frequently repaired using iliosacral screws to stabilize the fracture. Stimulus evoked electromyography, using pulsed current stimuli provided through the drill bit cathode, has been advocated to prevent nerve root injury during iliosacral screw insertion. Our objective was to examine the effects of anode location, drill bit position, and anatomical structure on the nerve monitoring technique. A three-dimensional finite element model was constructed from computed tomography data to evaluate the effectiveness of five anode locations at four stations of drill bit insertion. Results indicate that the anode location should be at the midline or on the side contralateral to drill bit insertion. Locating the anode at other positions, such that the nerve root is outside of the primary electromagnetic field, leads to an attenuated electromyographic response that will ultimately lead to the failure of the monitoring technique.

Two-level reconstruction of comminuted posterior-wall fractures of the acetabulum.

Our aim was to evaluate the efficacy of a two-level reconstruction technique using subchondral miniscrews for the stabilisation of comminuted posterior-wall marginal acetabular fragments before applying lag screws and a buttress plate to the main overlying posterior fragment. Between 1995 and 2003, 29 consecutive patients with acute comminuted displaced posterior-wall fractures of the acetabulum were treated operatively using this technique. The quality of reduction measured from three standard plain radiographs was graded as anatomical in all 29 hips. The clinical outcome at a mean follow-up of 35 months (24 to 90) was considered to be excellent in five patients (17%), very good in 16 (55%), good in six (21%) and poor in two (7%). The use of the two-level reconstruction technique appears to provide stable fixation and is associated with favourable results in terms of the incidence of post-traumatic osteoarthritis and the clinical outcome. However, poor results may occur in patients over the age of 55 years.

Accuracy of detecting screw penetration of the acetabulum with intraoperative fluoroscopy and computed tomography.

BACKGROUND: The purpose of this study was to determine the accuracy of computed tomography and fluoroscopy in assessing joint penetration by periacetabular screws. METHODS: A 3.5-mm acetabular periarticular screw was inserted in each of thirty-nine cadaveric hemipelves. Twenty screws were intentionally directed to violate the articular surface, whereas nineteen screws were positioned to avoid the articular surface. Using two fluoroscopic views (tangential and axial) in a manner simulating the clinical setting, an examiner blinded to the actual screw location determined whether each screw was violating the articular surface. In addition, each hemipelvis was examined with computed tomography with use of two different techniques: (1) a 1-mm slice thickness at 1-mm intervals, and (2) a 4-mm slice thickness at 3-mm intervals. Each scan was evaluated by another examiner who was blinded to the actual screw location. Sensitivity, specificity, and percent correct interpretations were then calculated for each method. RESULTS: The sensitivity, specificity, and percent correct interpretations were 95%, 84%, and 90%, respectively, for axial fluoroscopy; 85%, 89%, and 87% for tangential fluoroscopy; 100%, 84%, and 92% for the computed tomography scans with a 1-mm slice thickness at 1-mm intervals; and 100%, 58%, and 79% for the computed tomography scans with a 4-mm slice thickness at 3-mm intervals. Tangential fluoroscopy was found to be more specific than the computed tomography scans with a 4-mm slice thickness at 3-mm intervals (p = 0.02). No other significant differences were found. CONCLUSIONS: Fluoroscopy and computed tomography are equally accurate for determining intra-articular screw penetration. Computed tomography scans with thick slices (4 mm at 3-mm intervals) have a low specificity. Their use postoperatively may lead to a false-positive interpretation of the scan and unnecessary exploration of a hip for screw penetration.

Fractures of the greater trochanter: intertrochanteric extension shown by MR imaging.

OBJECTIVE: To demonstrate the MR depiction of the intertrochanteric or femoral neck extension of fractures of the greater trochanter, when standard radiographs show only a fracture of the greater trochanter. DESIGN AND PATIENTS: A retrospective review was performed of the MR and radiographic findings in 13 consecutive patients (10 men, 3 women; ages 24-86 years) with radiographic evidence of fracture of the greater trochanter who were examined with MR imaging. RESULTS: The MR study displayed the fracture of the greater trochanter in all cases. In all but three patients, MR examinations displayed an extension of the fracture into the intertrochanteric region, and in one, also an extension into the femoral neck, although the cortex at this level was not interrupted. CONCLUSION: When there is radiographic evidence of an isolated fracture of the greater trochanter, MR often shows an intertrochanteric or femoral neck extension of the fracture in both young and older adults. This finding may be a factor in determining the need for surgical intervention.

Open reduction and internal fixation of posterior wall fractures of the acetabulum.

The results of 94 patients with posterior wall fractures of the acetabulum associated with hip instability treated within 3 weeks of injury by open reduction and internal fixation were reviewed. Patients were followed up for an average of 3.5 years (range, 1-13 years). Fracture reductions were graded as anatomic (0-1 mm displacement) in 92 patients and imperfect (2-3 mm displacement) in two patients, as determined by plain radiography. However, postoperative computed tomography scans obtained in 59 patients revealed incongruency of more than 2 mm in six patients and fracture gaps of 2 mm or more in 44 patients. Complications included deep wound infection (one patient), deep vein thrombosis, (seven patients), and revision surgery to redirect an errant screw (one patient). Clinical outcome was graded as excellent in 34 patients (36%), good in 49 (52%), fair in two (2%), and poor in nine (10%). Radiographic results were excellent in 79 hips (84%), good in four (4%), fair in two (2%), and poor in nine (10%). There was a strong association between clinical outcome and radiographic grade. Variables identified as risk factors for an unsatisfactory result included age greater than 55 years, a delay greater than 24 hours from the time of injury for reduction of a hip dislocation, a residual fracture gap greater than 1 cm, and severe intraarticular comminution. The apparent disparity between the accuracy of surgical fracture reduction, as determined by plain radiographs obtained postoperatively, and clinical outcome is explained only partially by the limitations of plain radiography. Other variables are involved, many of which are under the surgeon's control but some are not. As is the case with other acetabular fracture types, the best results are predicated on anatomic fracture reduction.

Pilon fractures. Treatment protocol based on severity of soft tissue injury.

One hundred seven pilon fractures in 107 patients were treated according to a staged prospective protocol. All pilon fractures were stabilized immediately by the application of calcaneal traction. Open fractures or fractures in patients with multiple injuries were stabilized with traveling traction that was applied in the operating room. A distraction computed tomography scan was obtained before definitive treatment. Treatment groups were based on the degree of soft tissue compromise. Forty-one patients with Tscherne Grade 0 or Grade I injuries underwent open reduction and internal fixation (open plating) using contemporary techniques and low-profile implants. Sixty-four patients with Tscherne Grade II and Grade III closed injuries and all patients with open fractures underwent definitive treatment with limited open reduction and stabilization using small wire circular external fixators. Clinical and radiographic evaluations were performed at an average 4.9 years after injury. For all fracture types (AO classification), 81% of the patients who were treated with external fixation and 75% of the patients who were treated with open plating had good or excellent results. For severe fracture patterns (Type C), patients in both groups had significantly poorer results than patients with Types A and B fractures. The patients in the open plating group had a significantly higher rate of nonunion, malunion, and severe wound complications compared with the patients who received external fixation for Type C fracture patterns. Because of the increased incidence of bony and soft tissue complications when treating open or closed Type C fractures, use of limited exposures and stabilization with small wire circular external fixators is recommended.

Evaluation of intraoperative nerve-monitoring during insertion of an iliosacral implant in an animal model.

BACKGROUND: The use of continuous electromyographic and somatosensory-evoked-potential monitoring systems has been advocated to assist in avoiding nerve-root injury during operations on the pelvic ring. More recently, it was suggested that stimulus-evoked electromyographic monitoring may further decrease the risk of iatrogenic nerve-root injury during posterior pelvic fixation by enabling the surgeon to determine the actual distance of an implant from a nerve root. The purpose of the current study was to evaluate the relative efficacy of these three methods of monitoring for minimizing the risk of neural injury during the placement of iliosacral implants. METHODS: While the function of the first sacral nerve root was monitored with the use of stimulus-evoked electromyographic, continuous electromyographic, and somatosensory-evoked-potential monitoring techniques, a 2.0-millimeter stainless-steel Kirschner wire was progressively inserted, guided by a high-speed computerized tomographic scanner, into the first sacral body of seventeen hemipelves in nine dogs. The end point was contact with the nerve as demonstrated by the computerized tomographic images. It was expected that this end point would be heralded by a burst of spontaneous electromyographic activity and an abnormal somatosensory-evoked-potential signal. Anatomical dissection at the completion of the study documented the final position of the Kirschner wire. RESULTS: Anatomical dissection demonstrated compression or penetration of the nerve root in sixteen of the seventeen specimens. A spontaneous burst of electromyographic activity was not recorded for any specimen on continuous electromyographic monitoring; this finding was significantly different from what had been expected (p<0.001). Because of technical problems, somatosensory evoked potentials could be recorded for only twelve hemipelves that had nerve-root compression or penetration, and abnormal somatosensory evoked potentials were recorded for only one of the twelve; this finding was significantly different from what had been expected (p<0.001). A total of 113 stimulus-evoked electromyographic data points were obtained. The correlation coefficient for the relationship between the current threshold recorded with stimulus-evoked electromyographic monitoring and the distance of the wire from the nerve was 0.801 (p<0.001). The actual measured current thresholds were of an observed proportion not different from what had been expected (p = 0.48). CONCLUSIONS: Continuous electromyographic and somatosensory-evoked-potential monitoring techniques failed to indicate contact with the nerve root reliably in this animal model. However, stimulus-evoked electromyographic monitoring consistently provided reliable information indicating the proximity of the implant to the nerve root.

Retrograde nailing of the femoral shaft.

Retrograde intramedullary nailing of fractures of the femoral shaft with use of a distal intercondylar intra-articular entry portal is a relatively new surgical technique. This method of nailing represents a modification of the previously described procedure in which an extra-articular entry portal in the medial femoral condyle was used. The earlier procedure was plagued by technical difficulties, which limited its use; these problems were mainly related to the fact that the entry portal was not in line with the intramedullary canal, as well as to the fact that purpose-specific implants and instrumentation were not available. Modification of this technique, by using the intercondylar entry portal and a nail designed for retrograde insertion, has proved very effective in clinical studies. There have been theoretical concerns regarding postoperative knee function and intraoperative injury to important anatomic structures, such as branches of the femoral nerve; however, laboratory and clinical findings have dispelled many of these concerns and have provided firm support for continued use of the technique. Nonetheless, further study is required to delineate the long-term outcome of knee joint function. Current indications for use of this technique include multisystem injuries, multiple fractures (including ipsilateral lower-limb combination injuries), ipsilateral vascular injuries, periprosthetic fractures, and morbid obesity.

Ultrasound of fracture and bone healing.

This article reviews the ultrasound appearance of common fractures that may mimic other pathologies. Recent works suggest a role for ultrasound in the assessment of callus formation in delayed union of fractures and following the Ilizarov reconstructive procedures.

Unreamed retrograde intramedullary nailing of fractures of the femoral shaft.

OBJECTIVE: To evaluate the efficacy of unreamed retrograde intramedullary (IM) nailing of fractures of the femoral shaft in a second series of patients using modifications suggested from our initial study. DESIGN: Prospective. SETTING: Level I trauma center. METHODS: Based on the findings of a previous study, we began a clinical series incorporating changes consisting of (a) inclusion of any patient with a femoral shaft fracture amenable to IM nailing (i.e., closed physes), (b) primary use of a split patellar tendon intercondylar distal femoral entry portal, and (c) the use of a full-length femoral implant having variable size availability and dynamization capability. Over a twelve-month period, thirty-four patients with thirty-five femoral shaft fractures were treated. The protocol called for planned dynamization in statically locked stable fractures and unstable fractures showing minimal healing at six to twelve weeks. Functional outcome was assessed by using the Knee Society clinical rating system. RESULTS: Incorporating the concepts of canal fill and early dynamization, there were only two nonunions (6 percent) in this series as compared with 14 percent in the previously reported series with an overall shorter time to union (12.6 versus 15 weeks). There were no infections or malunions. Postoperative complaints of knee pain were minimal (knee score average: 98 points) and knee function was excellent (knee score average: 97 points). CONCLUSIONS: Although not advocated as a replacement for other techniques, unreamed retrograde nailing is presented as a safe and beneficial fracture fixation method that should be added to the orthopaedic surgeon's treatment armamentarium. The operative technique is quick and simple, and blood loss is minimal. Early nail dynamization and early weight-bearing are important in minimizing the risk of nonunion.

Heterotopic bone formation in male and female rabbits.

We performed mechanical induction of heterotopic ossification in the quadriceps of the right hind limb of six male and six female sexually mature New Zealand white rabbits of similar size. The effect of sex difference on heterotopic bone was assessed by analyzing plain radiographs of the femur. The results indicate that a male/female sex difference in heterotopic bone formation cannot be demonstrated.

Outcomes following repair of quadriceps tendon ruptures.

OBJECTIVES: The purpose of this study was to examine critically the outcomes of patients sustaining a quadriceps tendon rupture and to compare outcomes in patients with bilateral simultaneous ruptures versus a unilateral rupture. DESIGN: Retrospective review. SETTING: Patients were treated at a Level I trauma center. PATIENTS/PARTICIPANTS: Fifty-one quadriceps tendon ruptures in thirty-nine patients were evaluated. A mean four-year follow-up (range 13 to 204 months) was available for forty-eight tendon ruptures. INTERVENTIONS: All patients except one were treated with operative repair of the quadriceps tendon rupture(s). MAIN OUTCOME MEASUREMENTS: Patients were assessed by physical examination, Lysholm and Tegner scores, a functional questionnaire, quadriceps isokinetic testing, and radiographs. RESULTS: A statistically greater number of patients in the bilateral simultaneous rupture group had a systemic illness associated with tendon rupture (p = 0.014). This result did not adversely affect outcome as compared with patients with unilateral ruptures. Mean range of motion was 123 degrees in injured knees. Eighty-four percent of working patients returned to their previous occupations. More than half the patients, however, in general the most active, could no longer participate in their preinjury recreational activities. Fifty-three percent of unilateral rupture patients had persistent quadriceps strength deficits (>20 percent) in the injured extremity. Both quadriceps and hamstring isokinetic testing correlated significantly with Lysholm and Tegner scores. CONCLUSIONS: Most patients with bilateral simultaneous and unilateral tendon repairs can expect a good range of motion and return to their previous occupation, but many have persistent weakness and difficulty returning to higher level sporting activities.

Intraoperative monitoring with stimulus-evoked electromyography during placement of iliosacral screws. An initial clinical study.

A consecutive series of twenty-seven patients who had thirty acute unstable (type-C) fractures of the pelvic ring was studied prospectively to evaluate the use of stimulus-evoked electromyography to decrease the risk of iatrogenic nerve-root injury during the insertion of iliosacral screws. A prerequisite for inclusion in the study was a normal neurological status preoperatively; somatosensory evoked potentials were monitored to further document the neurological status both before and after insertion of the screw or screws. A total of fifty-one iliosacral screws were inserted, and a current threshold of more than eight milliamperes was selected as the level that indicated that the drill-bit was a safe distance from the nerve root. Four of the fifty-one screws were redirected because of information obtained with stimulus-evoked electromyography. Postoperatively, all patients had a normal neurological status. Computerized tomography, although not accurate for detailed measurements, demonstrated that all of the screws were in a safe, intraosseous position. Monitoring with stimulus-evoked electromyography appears to provide reliable data and may decrease the risk of iatrogenic injury to the nerve roots during operations on the pelvic ring.

Reharvest of iliac crest donor site cancellous bone.

Patients requiring cancellous bone grafting of an extensive deficit or multiple bone grafting procedures often lack a sufficient quantity of autogenous cancellous bone. Canine studies have indicated that a potential exists for reharvesting autogenous cancellous bone from an iliac crest donor site using a trapdoor harvesting technique. However, significant human experience with this procedure has been lacking. This report describes four patients who underwent successful reharvesting of an iliac crest donor site that provided clinically sufficient autogenous cancellous bone graft material to treat an ongoing or a new skeletal problem. These patients all met specific criteria regarding use of the trapdoor method of bone graft harvest and a minimum 24-month interval between bone grafting procedures. Preoperative computed tomography scanning of the iliac crest was useful in documenting that sufficient cancellous bone was available for reharvest. It appears that iliac crest donor site reharvesting is a specific advantage of the trapdoor technique and is a possible alternative to multiple site grafting or the use of allograft or bone substitute materials.

Ultrasound for the early diagnosis of tibial fracture healing after static interlocked nailing without reaming: histologic correlation using a canine model.

OBJECTIVE: Ultrasound is thought to be clinically useful in evaluating bone formation through its presumed identification of fracture callus. However, documentation of the actual histology of the tissue identified by ultrasound has been lacking. The purpose of this study was to determine the histologic composition of the hyperechoic tissue "seen" by ultrasound. STUDY DESIGN: Unilateral fractures were created in eight canine tibias and then fixed by using locked intramedullary nailing without reaming. The limbs were studied at two, three, four, six, and eight weeks postoperatively with plain radiographs, ultrasound, and ultrasound-directed needle biopsy. RESULTS: The presence of a hyperechoic ultrasound signal was found to have a 100 percent correlation with the presence of hard fracture callus biopsy tissue. In addition, fracture union by ultrasound criteria significantly predated radiographic fracture union (5.6 vs. 7.3 weeks, p = 0.05). CONCLUSIONS: These results support and provide a scientific basis for the clinical use of ultrasound to assess tibial fracture healing following static interlocked nailing without reaming.

Ultrasound for the early diagnosis of tibial fracture healing after static interlocked nailing without reaming: clinical results.

OBJECTIVE: Based on the results of a pilot study indicating the potential value of ultrasound (US) as a diagnostic tool for the early assessment of fracture healing and the related need for secondary operative procedures in patients treated by statically locked intramedullary (IM) nailing without reaming, a protocol was established for a larger scale prospective trial. The purpose of this study was to evaluate the outcome of this follow-up trial. DESIGN/METHODS: All skeletally mature patients admitted to the Henry Ford Hospital (Detroit, Michigan) from January 1993 to August 1994 who had sustained an acute fracture of the tibial shaft and who were treated by statically locked IM nailing, without reaming, were candidates for study. Forty-seven patients with fifty fractures that could be evaluated by US were included. The adopted determinants for fracture healing were complete disappearance of the IM nail on US examination performed at six weeks postoperatively, or progressive disappearance of the nail noted between the initial six-week study and a second nine-week US examination, both in conjunction with periosteal callus formation. Radiographs were obtained to monitor maintenance of reduction and to further evaluate fracture healing. RESULTS: Of thirty-eight fractures with a positive US (thirty-two at six weeks, six at nine weeks), thirty-seven healed uneventfully, a positive predictive value of 97 percent. Radiographic fracture healing was not evident until, on average, nineteen weeks after injury. The single false-positive fracture progressed to nonunion. Of the twelve fractures with negative US studies, ten underwent secondary procedures (nine dynamization, one bone graft), with four progressing to nonunion. Two patients refused secondary surgery; screw failure occurred in both. Otherwise, there were no hardware failures in this series. CONCLUSIONS: The results of this study indicate that US may provide important prognostic information concerning fracture healing after unreamed tibial nailing, upon which subsequent treatment can be based.

Comparison of the compression hip screw with the Medoff sliding plate for intertrochanteric fractures.

The Medoff sliding plate was designed to achieve compression along the femoral neck and the longitudinal axis of the femoral shaft theoretically to improve the treatment of intertrochanteric hip fractures. The Medoff sliding plate was compared with a standard compression hip screw in a randomized, prospective study for the fixation of 160 stable and unstable intertrochanteric fractures with an average followup of 9.5 months (range, 6-26 months). Overall, 91 fractures were treated using the compression hip screw and 69 were treated with the Medoff sliding plate. Stable fracture patterns (46) united without complication in both treatment groups. Unstable fractures (114) had an overall failure rate of 9.6%, 14% (nine patients) with the compression hip screw and 3% (two patients) with the Medoff plate; this difference was significantly different. The time to union for the 114 unstable fractures was not significantly different between the two devices. For all patients, no differences in lengths of hospitalization, return to ambulatory status before fracture, postoperative living status, or postoperative pain was observed between the two device groups. Use of the Medoff plate for all fracture types was associated with a significantly higher amount of blood loss and operating time.

Intraoperative stimulus-evoked electromyographic monitoring for placement of iliosacral implants: an animal model.

OBJECTIVE: A canine model was designed to evaluate the feasibility of stimulus-evoked electromyographic (EMG) monitoring of the lumbosacral nerve roots during the insertion of iliosacral implants. STUDY DESIGN/METHODS: Four 2.5-millimeter Kirschner wires (K-wires) were percutaneously inserted under general anesthesia into the S1 body of each of five dog hemipelves using C-arm fluoroscopy image-intensifier control in an actual attempt to compromise the S1 canal and the S1 nerve root. A searching current of twenty milliamperes was initially applied to the K-wire with monitoring electrodes placed in the gastrocnemius muscle. Current thresholds required to evoke an EMG response were recorded for each K-wire. Actual K-wire location was determined by anatomical dissection. RESULTS: Evaluation of these twenty wires revealed that current threshold was directly related to the proximity of the K-wire to the nerve root, with a correlation coefficient of 0.94 (p < 0.001). CONCLUSIONS: Stimulus-evoked EMG monitoring provided reliable data indicating the proximity of the iliosacral implants to the sacral nerve root. This method of intraoperative nerve monitoring could potentially decrease the risk of iatrogenic nerve root injury during pelvic ring surgery. Further study is warranted.