Kinematics of the human pelvis following open book injury.

The objective of this study is to determine the three dimensional kinematics of the human pelvis including both sacroiliac joints following a simulated open book injury induced on cadavers by applying anterior-posterior compressive loads to the pelvis. An electromagnetic digitizing and motion tracking system was utilized to measure the morphology of the pelvis and the relative movements of its bones during this simulated open book fracture. The screw displacement axis method was used to describe the relative motion between the sacrum and each hipbone. Morphologically, it was found that the articular surfaces forming the sacroiliac joints could be approximated with planar surfaces directed from proximal and lateral to distal and medial and from posteromedial to anterolateral. The kinematic data obtained from this study indicate that there is a direct correlation between the opening of the symphysis pubis and the opening of the sacroiliac joint (SIJ) during open book injury. This suggests that the extent of injury of the SIJ maybe estimated from the degree of opening of the symphysis pubis as demonstrated on anteroposterior (A-P) x-rays. The results obtained from this study also indicate that the motion of the hipbone with respect to the sacrum on the side of the sacroiliac joint opening is almost a pure rotation, which translates clinically on the A-P x-rays as pure opening of the SIJ without vertical displacement. The average axis of rotation was found to be almost parallel to the SIJ planar articular surface. Furthermore, the pubic bone on the side of SIJ opening was found to displace inferiorly and posteriorly. One can thus conclude that in open book pelvic injuries, the pubic bone on the side of injury displaces inferiorly on the outlet projection x-rays with no vertical displacement of the SIJ. This is important since the initial assessment of the open book injury in the emergency room includes outlet projection x-rays. From this study, the relative vertical positions of the pubic bones on these x-rays can help the surgeon in differentiating open book fracture injury from other pelvic injuries.

Management of metastatic tumors of the spine: strategies and operative indications.

The spinal column is the most frequent site of bone metastasis in the body. Spine surgeons are often involved in the care of these patients only after nonoperative management has failed. Because surgery has been viewed as no better than radiotherapy in the treatment of metastasis of the spine, it has only been used as a salvage approach. These views are based on a body of literature in which laminectomy combined with radiotherapy was compared with radiotherapy alone. Anterior approaches to the spine are now popular and familiar to most surgeons. These approaches allow direct access to the metastatic lesion, reconstruction of the anterior vertebral column, and the placement of anterior instrumentation. Outcomes are frequently much better when this combined treatment is used instead of radiotherapy alone. In selected patients, surgery may be desired as first-line therapy before radio- or chemotherapy has been initiated. The controversy surrounding surgery for metastatic spinal disease is reviewed. Treatment strategies, both operative and nonoperative, are presented. Indications and strategies for surgery are also presented, and the supporting literature is reviewed.

Axillary view of the glenoid articular surface.

The glenoid articular surface is best studied radiographically on a tangential projection with both true anteroposterior and axillary views. Forty-one dry scapulas were studied under fluoroscopy to define the axillary projection that would provide a true scapular lateral view. The superior and inferior articular margins were marked with radiopaque solder wires. A true axillary view was obtained when the projection of the wires superimposed. The projection of the cortical bone of the posterolateral surface of the coracoid was noted to be continuous with the projection of the subchondral cortical bone of the glenoid articular surface when the latter was viewed tangentially. An illustrative case is shown in which a screw was mistakenly seen violating the glenohumeral joint; however, with the defined true axillary view, the actual position of the screw was demonstrated. X-ray films taken of another 8 cadaver shoulders were used to study the position of screws inserted about the glenoid articular surface. The soft tissue shadow superimposition on the inferior glenoid margin can lead to a misinterpretation of the superior margin as the whole glenoid articular surface. Because soft tissue can interfere with the appreciation of the glenohumeral joint line on an axillary view, a projection that will show a continuous line of the coracoid and glenoid articular surface should be obtained, and it will indicate a tangential view of the joint.

External rotation-lateral view of the ankle in the assessment of the posterior malleolus.

Demonstration of a posterior malleolar fragment on a radiograph of an ankle fracture is important in the diagnosis and evaluation of posterior malleolus fractures. The size and extent of displacement of a posterior malleolar fragment can be evaluated. The diagnosis of non-union of the posterior malleolus is also important because it can lead to failure of reduction of ankle fractures. The authors present a case in which nonunion of the posterior malleolus was diagnosed by an external-rotation lateral view of the ankle. This could not be demonstrated on the AP or the lateral views. Thirteen cadaver feet were then used to study the external-rotation lateral view. A posterior malleolar fracture was created, and the borders of the fracture line were marked with solder wire. The average external rotation angle required to best demonstrate the posterior malleolar fracture was 50 degrees (range, 43 degrees -55 degrees). The actual size of the posterior malleolus fragment was measured and compared to the x-ray measurement. There was a 0.10 correction for the determination of the actual size of the fragment. The unmarked fragment could not be demonstrated on AP and lateral views.

Extensile approach to the anterolateral surface of the humerus and the radial nerve.

A proposed approach to the anterolateral surface of the humeral shaft that would allow for exploration of the radial nerve was studied in 30 cadaver arms. The incision starts proximally along the posterior border of the deltoid muscle and extends anteriorly and distally over the lateral border of the biceps muscle. A deep dissection is made in the internervous plane between the deltoid and the triceps muscles proximally and between the longitudinally split fibers of the brachialis muscle distally. The approach provides access to the anterolateral surface of the humerus up to the level of the axillary nerve and the posterior circumflex humeral vessels. The insertion of the deltoid muscle into the anterior border of the humerus is preserved and the radial nerve is protected by the triceps muscle proximally and by the retracted lateral portion of the brachialis muscle distally. The entire course of the radial nerve in the arm can be exposed. Proximally, the radial nerve can be exposed by elevating the lateral head of the triceps muscle from the humerus. Distally, the radial nerve can be exposed between the brachioradialis and the brachialis muscles. A plate can be applied on the anterolateral surface of the humerus without having to elevate the firmly attached anterior deltoid insertion.

Entry point of reconstruction nail.

If the femoral neck is involved in a pathological process, the surgeon may avoid a base neck entry for the reconstructive nail. If a trochanteric entry is selected, the surgeon must be aware that the nail has to be driven more distally in order to place the neck screws properly. Violation of the knee joint is a consideration, and so is varus malposition.

Radiographic and CT evaluation of tibiofibular syndesmotic diastasis: a cadaver study.

Twelve cadaver lower limbs were used for radiographic and CT assessment of the tibiofibular syndesmosis. Plastic spacers were placed in the distal tibiofibular intervals of each specimen in successive 1-mm increments until diastasis could be appreciated on the plain radiographs. All 2- and 3-mm diastases could be noted and clearly identified on CT scans, while the 1-, 2-mm, and half of the 3-mm syndesmotic diastases could not be appreciated with routine radiographs. CT scanning is more sensitive than radiography for detecting the minor degrees of syndesmotic injuries. Therefore, a CT scan can be performed in cases of syndesmotic instability after ankle injuries and for preoperative or postoperative evaluation of the integrity of the distal tibiofibular syndesmosis in cases of doubtful condition of the syndesmosis.

Operative technique for inside-out repair of the triangular fibrocartilage complex.

A technique for arthroscopic inside-out repair of peripheral traumatic (type 1B) tears of the triangular fibrocartilage complex is reported. The technique can be performed using zone-specific cannulas that are commonly used for repairing meniscal tears in the knee. Anatomic dissections were used to show the safe regions around the TFCC where tears are amenable to this type of repair.

Ankle fractures involving the fibula proximal to the distal tibiofibular syndesmosis.

Thirty-two cases of ankle fractures associated with fibular fractures above the distal tibiofibular syndesmosis were studied. All were treated with open reduction and internal fixation. The average follow-up was 25 months. The results of the postoperative evaluation were rated, based on subjective clinical criteria, as good, fair, and poor. According to the Lauge-Hansen classification, there were 17 (53%) cases of supination-external rotation injury (2 stage 2 and 15 stage 4), 9 (28%) cases of stage 3 pronation-abduction injury, and 6 (19%) cases of pronation-external rotation injury (3 stage 3 and 3 stage 4). All cases could be classified as Weber type C or as suprasyndesmotic, fibular diaphyseal fracture (44-C) according to the Orthopaedic Trauma Association classification. In 18 (56%) cases, the fracture was associated with ankle dislocation. There were seven (22%) open fractures, (two grade I, four grade II, and one grade IIIA). Syndesmotic screws were used in 23 (72%) cases (12 supination-external rotation injury, 6 pronation-external rotation injury, and 5 pronation-abduction injury). The syndesmotic screw was removed after an average of 9 weeks. Four (13%) nonunions and two (6%) delayed unions of the fibula were treated with bone grafting and/or hardware revision and eventually healed. Three of the nonunions had poor clinical results because of degenerative ankle joint arthritis in two (one of them ended in arthrodesis) and deep infection, which was eventually cured, in the third. The fourth nonunion had a fair result. One of the delayed unions had a fair result (an obese patient) and the other had a good result. Two patients developed deep infections; one ended in gangrene and amputation in a diabetic patient, and the other was a patient with fibular nonunion that eventually healed. Three patients had superficial infections that were treated successfully. Of the 32 cases, 23 (72%) showed good results, 4 (13%) showed fair results, and 5 (16%) showed poor results. The cases with poor results included three fibular nonunions, one deep infection, and one recurrent superficial infection and wound dehiscence after hardware removal. A syndesmotic screw is usually needed in cases of fracture-dislocations. Two patients with occult fibular nonunions developed diastasis of the syndesmosis after removal of the syndesmotic screw. It was found that reduction and temporary pinning of the distal tibiofibular joint helps achieve fibular length, which is crucial to restoring the biomechanics of the ankle joint. It seems advisable not to remove the syndesmotic screw until there are signs of healing of fibular fracture to avoid diastasis of the distal tibiofibular joint. Bone grafting should be considered in high energy fractures with comminution. These complex injuries are associated with higher rates of complications. Poor results can be attributed to fracture factors, e.g., open fractures, infections; patient factors, e.g., obesity, lowered immunity as in diabetes, and noncompliance; and iatrogenic factors, e.g., early removal of syndesmotic screws.

Vertical displacement of the symphysis pubis in unilateral open book pelvic injury.

Nineteen cases of external rotation (open book) injury of the pelvis were studies retrospectively. An apparent vertical displacement of the hemipelvis was detected on anteroposterior radiographic views in association with the separation of the symphysis pubis and opening of the sacroiliac joint. This could be confused with a vertically unstable situation; however, careful examination of the radiographs revealed that the public bone on the side of injury was displaced inferiorly. The articular portion of the corresponding sacroiliac joint on computed tomography was opened anteriorly, and the hemipelvis on the same side was externally rotated in all cases (indicating that the posterior sacroiliac ligaments were intact). An anatomic study was then performed on 10 cadaveric pelves. The symphysis pubis and the anterior sacroiliac ligament on one side were sharply disrupted, and the pelvis was gradually externally rotated. The pubic bone on the side of the sacroiliac disruption displaced inferiorly as the external rotation progressed. It is important to differentiate between the inferiorly displaced pubic bone on the side of injury in cases of external rotation injury and the superiorly displaced pubic bone on the side of injury in cases of vertically unstable pelvic injuries. This may eliminate unnecessary procedures such as skeletal traction or pinning of the sacroiliac joint.

Radial artery injury in association with fractures of the trapezium.

Three cases of trapezial fractures in which the radial artery was injured are reported. The injuries occurred during the initial trauma in one, when internal fixation was done in the second, and during hardware removal in the third. Six cadaveric wrists were dissected to study the relationship between the course of the artery and the trapezium.

Radiology of the sacroiliac joint.

STUDY DESIGN: Radiology of the sacroiliac joint was investigated by obtaining different and multiple radiographs of cadaveric pelves marked with solder metal wire and radiopaque paint. OBJECTIVES: To demonstrate the orientation of the sacroiliac joint on various, radiographic views. SUMMARY OF BACKGROUND DATA: Interpretation of the sacroiliac joint projection on plain radiography is difficult. It requires an understanding and appreciation of its components and their orientation. Emphasizing the definition of the orientation of the plane of the joint on the different projection views of the sacroiliac joints can aid the orthopaedic surgeon in obtaining the proper radiographs and in the proper interpretation of the different radiographic views. METHODS: Nineteen sacroiliac joints from 10 cadaveric pelves, 5 male and 5 females were studied. Each joint was found to be composed of three portions: anterosuperior, middle, and posteroinferior portions, each lying in a different plane. Each sacroiliac joint was marked with solder wires and radiopaque paint to define the orientation of each of the three portions of the joint on radiographs. The following radiographic projection views were taken for each joint anteroposterior, lateral, inlet, craniocaudal axial, outlet, lithotomy and oblique views. For the oblique views, the angulation of the x-ray tube needed to view each portion of the joint tangentially was recorded. RESULTS: There was a wide variation in the orientation of the planes of the joint portions between the right and the left sides as well as between different pelves. Although the twisting of the plane of the whole joint produced by the successive examination of the portions could be either internal or external, it was the same bilaterally in a given specimen. The outlet and lithotomy views provided the best tangential representation of the two sacroiliac joints on one film. CONCLUSION: The sacroiliac joint is composed of three portions oriented in different planes. To study the sacroiliac joints, it seems desirable to obtain an anteroposterior view of the pelvis with the patient in a lithotomy position; then, if needed, each joint can be radiographed separately by using oblique views. It is important to not that the plane of the articular portion of the joint can be directed from anterolateral to posteromedial, and therefore, the oblique views should be obtained accordingly.

Open reduction and internal fixation with bone grafting of clavicular nonunion.

BACKGROUND: Although clavicular fractures are common, nonunion of the clavicle is a rare complication. However, it can be disabling, presenting mainly with pain, limitation of shoulder movement, and/or compression of the brachial plexus. The technical difficulty in securing adequate skeletal stabilization and the unique anatomic features of the clavicle pose a challenge for the orthopedic surgeon. METHODS: Sixteen patients with symptomatic nonunion of the clavicle were studied. They were nine men and seven women with a median age of 34 years (range, 15-52 years). The average follow-up was 12.9 months (range, 9-24 months). The nonunion was hypertrophic in 11 cases, atrophic in five cases, and showed pseudoarthrosis in one case. The primary indication for performing the operation was pain in all cases. Five of the 16 cases had previous operations. All cases were treated with open reduction and internal fixation using a reconstruction plate or a dynamic compression plate. Double plating was used in three cases. Autogenous bone grafting was applied in 14 cases and corraline hydroxyapatite in one case. RESULTS: Fifteen of the 16 fractures eventually healed with complete resolution of the preoperative pain, except in two cases who had persistent mild pain. The hardware was removed after union in one case. One hardware failure required revision and eventually went on to heal. Another hardware failure required removal because of pain. The pain subsided despite the persistent nonunion. The same patient had hematoma at the site of the bone graft and continued to have pain until the last follow-up. CONCLUSION: Plating and bone grafting of the clavicle is an effective method of management of painful nonunion, and it has minimal complications.

The infrapatellar branch of the saphenous nerve: an anatomic study.

OBJECTIVES: To describe the course of the infrapatellar branch of saphenous nerve (IPBSN) and define a risk zone in which the nerve would probably be located. DESIGN AND MATERIALS: The course of the IPBSN was studied in twenty-eight cadaver specimens (fifteen male and thirteen female) chosen haphazardly. SETTING AND MAIN OUTCOME MEASUREMENTS: The adductor tubercle and the junction between the inferior pole of the patella and the medial (point A) and lateral (point B) borders of the patellar tendon were taken as reference points. The level of the joint line as well as the point of crossing of the IPBSN at the joint line were measured in relation to point A. RESULTS: The IPBSN was located at 7.7 +/- 16.8 mm posterior to the adductor tubercle at the level of point A; at 0.8 +/- 20.5 mm anterior to the adductor tubercle at the level of joint line; and at 12.1 +/- 18.8 mm anterior to the adductor tubercle at 30 degrees from point A. The IPBSN crossed to the lateral border of the patellar tendon in 10 of the 28 specimens (36%). The vertical distance between point B and the nerve was 37.8 +/- 23.5 mm. Three zones are defined in relation to point A: a safe zone, a gray zone, and a risk zone. The limits of the safe zone could be represented by a curved line that crosses the following points: 31.0 mm medial to point A and at the same level; 17.2 mm from point A at the joint line; 13.2 mm infromedial to point A at an angle of 30 degrees; 9.6 mm at an angle of 60 degrees; and 5.8 mm inferior to point A. CONCLUSION: Avoiding the risk zone in which the nerve would probably be located and performing a blind puncture or an arthrotomy within the safety zone may decrease the incidence of IPBSN injury.

Anatomic considerations for a modified posterior approach to the scapula.

A modified posterior approach to the scapula was tested on 20 cadavers. The approach also was used in 2 cases with fractures involving the scapular neck and glenoid fossa. The incision is C shaped, with the convexity directed toward the lateral angle of the scapula. The posterior muscle fibers of the deltoid are reflected laterally after detaching them from their origin. The infraspinatus is mobilized without division to expose the posterior surface of the scapular neck and glenoid. Access to the rest of the posterior and the superior surfaces of the glenoid can be achieved by osteotomizing the acromion. The suprascapular neurovascular bundle is identified and protected at an average of 1.4 +/- 0.1 cm from the glenoid rim, where it is adherent to the spinoglenoid angle of the scapula. The circumflex scapular artery is protected at the lateral border of the scapula at an average of 2.8 +/- 0.5 cm from the inferior glenoid margin. The axillary nerve is protected inferior to the teres minor. However, care should be taken not to excessively retract the teres minor because the nerve lies in close proximity to the shoulder joint capsule.

Components of the posterior calcaneal facet: anatomic and radiologic evaluation.

The calcaneal facet of the posterior subtalar joint can be divided into two portions: an anterolateral portion and a posteromedial portion. The importance of this consideration is that the two portions of the facet do not lie in the same plane. This should be taken into consideration when interpreting radiographs of the subtalar joint. Measurements from 50 dry-bone specimens and radiographs of 10 cadaver specimens were taken. The radiographs were obtained after marking the posterior subtalar joint to demonstrate the corresponding site of each facet portion on radiographs. The posteromedial portion lies almost in the transverse plane, making an angle of approximately 40 degrees with the anterolateral portion. Each radiographic projection was explained by demonstrating the orientation of markings applied to the specimens and correlated to the data derived from the angular measurements. A protocol of sequential radiographs that can be used to evaluate the posterior subtalar joint is proposed.

Anatomic considerations for safe placement of calcaneal pins.

Placement of a Steinmann pin in the calcaneus is indicated in various orthopaedic conditions. Planning the point of entry and the direction of transcalcaneal pin insertion is crucial for avoidance of neurovascular injury, tendon injury, and subtalar joint violation. Fifteen cadaveric feet were studied in which transfixing calcaneal pins were inserted in posteromedial and anteromedial sites. The posteromedial site was at a point 3/4 the distance between the palpable tip of the medial malleolus and the heel, with the pin inserted transversely. The anteromedial site was at the sustentaculum tali with the pin inserted transversely angled 25 degrees to 30 degrees inferolaterally. Radiographs were then taken and the specimens were dissected to determine the path of each pin and the safe and danger zones for transcalcaneal pin placement. It was concluded that the posteromedial calcaneal pin site is safer and easier to determine.

Anatomic considerations for the anterior exposure of the proximal portion of the radius.

The rate of posterior interosseous nerve injury is still of major concern during surgical exposure of the proximal portion of the radius. The objective of this study was to find the best way to protect the important neurovascular structures during anterior exposure of the proximal radius and to define the safest anatomic orientation for plate and screw placement during open reduction and internal fixation of the proximal radius. In 30 cadaveric upper limbs, the proximal portion of the radius was exposed through a modified anterior Henry approach. The important anatomic structures were localized and demonstrated on radiographs. Plates and screws were applied anterolaterally (in five specimens) and laterally (in another five specimens), and the locations of the safe and danger zones were noted. Lateral placement of the plate is preferred over the more commonly used anterolateral plating, because it carries less risk of injuring the posterior interosseous nerve during screw application and it does not impinge on the biceps tendon and block pronation.

Talar neck fractures: anatomic considerations for posterior screw application.

The bony window available for posterior screw placement in the talus and the morphology of the talar neck were studied in 50 dry tali. In addition, 12 cadaver specimens were used to study the posterolateral approach. The bony window was bounded medially by the lateral tubercle of the posterior process of the talus, laterally by the fibular facet, superiorly by the trochlear articular surface, and inferiorly by the posterior calcaneal facet. The average vertical thickness at 2-mm increments was recorded across the talar neck to define the bony mass available for screw insertion. The smallest thickness of the talar neck was at a point 2 mm medial to the lateral border. The thickness progressively increased in a medial direction. The superior talar neck surface was found to have an average width of 18.4 +/- 1.6 mm. The angle formed between the superior and lateral surfaces of the talar neck averaged 29.3 degrees, which would account for the better delineation of the lateral border of the neck under fluoroscopy of the talus with the foot in pronation. The diameter of the screw in relation to the window height should be considered.

Anatomic and X-ray film studies of the distal articular surface of the radius.

Knowledge of the surgical and topographic anatomy of the distal articular surface of the radius is valuable during diagnostic and operative procedures involving the distal radius. The aim of this study is to assist the surgeon in determining the location, displacement, and angulation of acute or healed distal radius articular fractures. Measurements were taken of the distal articular surface of 50 dry radii. Also, the margins and surfaces of the distal articular surface of 12 adult cadaver radii were marked by solder and radiopaque dye, respectively. X-ray films were then taken to define the margins and bony landmarks. The lunate facet surface area (53%) was found to be slightly larger than the scaphoid facet surface area (47%). Both the palmar tilt and the radial inclination were demonstrated on the marked x-ray films. Using the 30 degrees cephalad angled anteroposterior projection of the distal radius can help assess the dorsomedial fragment of the lunate fossa in a die-punch fracture.