Evolution of the internal fixation of long bone fractures. The scientific basis of biological internal fixation: choosing a new balance between stability and biology

The advent of 'biological internal fixation' is an important development in the surgical management of fractures. Locked nailing has demonstrated that flexible fixation without precise reduction results in reliable healing. While external fixators are mainly used today to provide temporary fixation in fractures after severe injury, the internal fixator offers flexible fixation, maintaining the advantages of the external fixator but allowing long-term treatment. The internal fixator resembles a plate but functions differently. It is based on pure splinting rather than compression. The resulting flexible stabilisation induces the formation of callus. With the use of locked threaded bolts, the application of the internal fixator foregoes the need of adaptation of the shape of the splint to that of the bone during surgery. Thus, it is possible to apply the internal fixator as a minimally invasive percutaneous osteosynthesis (MIPO). Minimal surgical trauma and flexible fixation allow prompt healing when the blood supply to bone is maintained or can be restored early. The scientific basis of the fixation and function of these new implants has been reviewed. The biomechanical aspects principally address the degree of instability which may be tolerated by fracture healing under different biological conditions. Fractures may heal spontaneously in spite of gross instability while minimal, even non-visible, instability may be deleterious for rigidly fixed small fracture gaps. The theory of strain offers an explanation for the maximum instability which will be tolerated and the minimal degree required for induction of callus formation. The biological aspects of damage to the blood supply, necrosis and temporary porosity explain the importance of avoiding extensive contact of the implant with bone. The phenomenon of bone loss and stress protection has a biological rather than a mechanical explanation. The same mechanism of necrosis-induced internal remodelling may explain the basic process of direct healing.

Complications following internal fixation of unstable distal radius fracture with a palmar locking-plate

OBJECTIVES

The increasing number of fixed-angle plate systems used to treat distal radius fractures carries with it the problem of determining the optimal fixation for unstable fractures. Our goal was to analyze the clinical and radiological outcomes of patients with displaced, unstable distal radius fractures treated with a palmar fixed-angle plate.

DESIGN

Prospective protocol; multicenter clinical study; retrospective analysis.

SETTING

Level 1 university trauma centers.

PATIENTS

Over a mean 15-month period (range, 12 to 27 months), 141 consecutive patients were treated for an unstable dorsally displaced distal radius fracture of which 114 or 81% were followed for 1 year or longer.

INTERVENTION

Open reduction and palmar internal fixation with a fixed-angle plate (2.4 mm LCP Distal Radius Plates; Synthes, Salzburg, Austria). Indication for surgical treatment was the inability to obtain or maintain fracture or articular alignment after initial closed reduction.

MAIN OUTCOME MEASURES

In a follow-up period, which had to be longer than 12 months, objective and subjective functional results (active range of motion; strength; Disabilities of the Arm, Shoulder, and Hand (DASH) score; visual analog scale (VAS); Green and O'Brien Score) and radiographic assessment (palmar tilt, radial inclination, ulnar variance, fracture union) were assessed. Potentials for complications were given special attention.

RESULTS

In the 114 patients followed for a minimum of 12 months, there were 21 men and 93 women with a mean age of 57 years (17 to 79 years). Fractures were classified according to the AO/ASIF classification system as type A2 (n = 39), A3 (n = 16), C1 (n = 24), C2 (n = 30), or C3 (n = 5). The modified Green and O'Brien Score revealed 31 excellent, 54 good, 23 fair, and 6 poor results. Active wrist motion averaged 54 degrees extension (82% as compared with the uninjured side) and 46 degrees flexion (72% as compared with the uninjured side). The average pronation was 81 degrees (95% as compared with the uninjured side), and the average supination was 82 degrees (95% as compared with the uninjured side). Mean grip strength at final follow-up was 70% of the uninjured side. Low residual pain values in the wrist were demonstrated: 81 patients (71%) were pain free, 17 patients (15%) had mild pain, 10 patients (9%) had moderate pain, and 6 patients (5%) had severe pain. The DASH score averaged 13 points (range, 0 to 39 points). Fracture union was achieved in all patients. A mean loss of palmar tilt of 3.4 degrees (range, 0 to 8 degrees), radial inclination of 0.4 degrees (range 0 to 2 degrees), and of the ulnar variance of 1.2 mm (range, 0 to 6 mm) was measured. The overall complication rate was 27% (31/114). The most frequent problems were flexor and extensor tendon irritation (57% of the total number of complications), including 2 ruptures of the flexor pollicis longus tendon, 2 ruptures of the extensor pollicis longus tendon, 4 cases of extensor tendon tenosynovitis, and 9 cases of flexor tendon tenosynovitis. Carpal tunnel syndrome was observed in 3 patients, and complex regional pain syndrome occurred in 5 patients. In 2 cases, loosening of a single screw was seen. Delayed fracture union occurred in 3 patients, and intraoperative intraarticular screw displacement was recognized in 1 patient. Neither clinical outcome nor complication rate were dependent on fracture type (intraarticular versus extraarticular).

CONCLUSION

Fixation of unstable dorsally displaced distal radius fractures with a fixed angle plate provides sufficient stability with minimal loss of reduction. Nevertheless, very distal palmar plate position can interfere with the flexor tendon system, too long screws can penetrate the extensor compartments, and distal screws in comminuted fracture patterns can cut through the subchondral bone and penetrate into the radiocarpal joint. Mindful of these problems, we consider that the complex fracture pattern of an unstable distal radius fracture cannot be treated by a single plate system and approach.

Evolution of the internal fixation of long bone fractures. The scientific basis of biological internal fixation: choosing a new balance between stability and biology

The advent of 'biological internal fixation' is an important development in the surgical management of fractures. Locked nailing has demonstrated that flexible fixation without precise reduction results in reliable healing. While external fixators are mainly used today to provide temporary fixation in fractures after severe injury, the internal fixator offers flexible fixation, maintaining the advantages of the external fixator but allowing long-term treatment. The internal fixator resembles a plate but functions differently. It is based on pure splinting rather than compression. The resulting flexible stabilisation induces the formation of callus. With the use of locked threaded bolts, the application of the internal fixator foregoes the need of adaptation of the shape of the splint to that of the bone during surgery. Thus, it is possible to apply the internal fixator as a minimally invasive percutaneous osteosynthesis (MIPO). Minimal surgical trauma and flexible fixation allow prompt healing when the blood supply to bone is maintained or can be restored early. The scientific basis of the fixation and function of these new implants has been reviewed. The biomechanical aspects principally address the degree of instability which may be tolerated by fracture healing under different biological conditions. Fractures may heal spontaneously in spite of gross instability while minimal, even non-visible, instability may be deleterious for rigidly fixed small fracture gaps. The theory of strain offers an explanation for the maximum instability which will be tolerated and the minimal degree required for induction of callus formation. The biological aspects of damage to the blood supply, necrosis and temporary porosity explain the importance of avoiding extensive contact of the implant with bone. The phenomenon of bone loss and stress protection has a biological rather than a mechanical explanation. The same mechanism of necrosis-induced internal remodelling may explain the basic process of direct healing.

Volar fixation for dorsally displaced fractures of the distal radius: a preliminary report

Using a volar approach to avoid the soft tissue problems associated with dorsal plating, we treated a consecutive series of 29 patients with 31 dorsally displaced, unstable distal radial fractures with a new fixed-angle internal fixation device. At a minimal follow-up time of 12 months the fractures had healed with highly satisfactory radiographic and functional results. The final volar tilt averaged 5 degrees; radial inclination, 21 degrees; radial shortening, 1 mm; and articular incongruity, 0 mm. Wrist motion at final follow-up examination averaged 59 degrees extension, 57 degrees flexion, 27 degrees ulnar deviation, 17 degrees radial deviation, 80 degrees pronation, and 78 degrees supination. Grip strength was 79% of the contralateral side. The overall outcome according to the Gartland and Werley scales showed 19 excellent and 12 good results. Our experience indicates that most dorsally displaced distal radius fractures can be anatomically reduced and fixed through a volar approach. The combination of stable internal fixation with the preservation of the dorsal soft tissues resulted in rapid fracture healing, reduced need for bone grafting, and low incidence of tendon problems in our study.

Responsiveness of the short form-36, disability of the arm, shoulder, and hand questionnaire, patient-rated wrist evaluation, and physical impairment measurements in evaluating recovery after a distal radius fracture

We evaluated the responsiveness of patient questionnaires and physical testing in the assessment of recovery after distal radius fracture. Patients (n = 59) were assessed at their baseline clinic visit and again 3 and 6 months after injury. At each visit patients completed a short form-36, Disability of the Arm, Shoulder, and Hand questionnaire, and patient-rated wrist evaluation (PRWE). At 3 and 6 months grip strength, range of motion, and dexterity were analyzed. Standardized response means (SRM) and effects sizes were calculated to indicate responsiveness. The PRWE was the most responsive. Both the PRWE (SRM = 2.27) and the Disability of the Arm, Shoulder, and Hand (SRM = 2.01) questionnaire were more responsive than the short form-36 (SRM = 0.92). The physical component summary score of the short form-36 was similar to that of the physical component subscales. Questionnaires were highly responsive during the 0- to 3-month time period when physical testing could not be performed. Of the physical tests, grip strength was most responsive, followed by range of motion. Responsive patient-rating scales and physical performance evaluations can assist with outcome evaluation of patients with distal radius fracture.

Volar fixed-angle plate fixation for unstable distal radius fractures in the elderly patient

PURPOSE

Increased incidence of falls and osteoporosis combine to make distal radius fractures a major cause of morbidity for the elderly patient. This report presents our experience treating distal radius fractures in the elderly population using a volar fixed-angle internal fixation plate.

METHODS

We reviewed retrospectively all patients older than 75 years treated during a period of 4 years and 7 months at our centers for unstable distal radius fractures using a volar fixed-angle plate. Postoperative management included immediate finger motion, early functional use of the hand, and a wrist splint used for an average of 3 weeks. Standard radiographic fracture parameters were measured and final functional results where assessed by measuring finger motion, wrist motion, and grip strength.

RESULTS

Of 26 patients that fit the inclusion criteria, we were able to evaluate 23 patients with 24 unstable distal radius fractures for an average of 63 weeks. Final volar tilt averaged 6 degrees and radial tilt 20 degrees, and radial shortening averaged less than 1 mm. The average final dorsiflexion was 58 degrees, volar flexion 55 degrees, pronation 80 degrees, and supination 76 degrees. Grip strength was 77% of the contralateral side. There were no plate failures or significant loss of reduction, although there was settling of the distal fragment in 3 patients (1-3 mm).

CONCLUSIONS

The treatment of unstable distal radius fractures in the elderly patient with a volar fixed-angle plate provided stable internal fixation and allowed early function. This technique minimized morbidity in the elderly population by successfully handling osteopenic bone, allowed early return to function, provided good final results, and was associated with a low complication rate.

Functional outcome and complications after volar plating for dorsally displaced, unstable fractures of the distal radius

PURPOSE

Despite the recent popularity of volar plating for dorsally displaced distal radius fractures there is a paucity of data documenting the results of this treatment method. The purpose of this study was to determine the functional outcome of patients treated with volar fixed-angle plating for dorsally displaced, unstable distal radius fractures.

METHODS

We reviewed the records of all patients treated at our institution with internal fixation using volar plates for dorsally displaced, comminuted distal radius fractures. Patients with follow-up periods shorter than 12 months were excluded from the study. Outcomes were evaluated at the latest follow-up examination with the Disabilities of the Arm, Shoulder, and Hand and the Gartland and Werley scoring systems.

RESULTS

We studied 41 patients with a mean age of 53 years. The average follow-up period was 17 months. All fractures were stabilized with volar locking plates. Radiographs in the immediate postoperative period showed a mean radial height of 11 mm, mean radial inclination of 21 degrees , and mean volar tilt of 4 degrees. At fracture healing the mean radial height was 11 mm, mean radial inclination was 21 degrees, and mean volar tilt was 5 degrees. The average score on the Disabilities of the Arm, Shoulder, and Hand questionnaire was 14 and all patients achieved excellent and good results on the Gartland and Werley scoring system, indicating minimal impairment in activities of daily living. Nine patients experienced postoperative complications. There were 4 instances of loss of reduction with fracture collapse, 3 patients required hardware removal for tendon irritation, 1 patient developed a wound dehiscence, and 1 patient had metacarpophalangeal joint stiffness.

CONCLUSIONS

Patients with unstable, dorsally displaced fractures of the distal radius treated with volar fixed-angle devices have good or excellent functional outcomes despite a high complication rate. When compared with previous reports on dorsal plating volar plates appear to have a higher incidence of fracture collapse but a lower rate of hardware-related complications. Complex fracture patterns thus mandate a careful and individualized approach.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic, Level III.

Open reduction and internal fixation of fractures of the radial head

BACKGROUND

The purpose of this retrospective study was to analyze the functional results following open reduction and internal fixation of fractures of the radial head and to determine which fracture patterns are most amenable to this treatment.

METHODS

Fifty-six patients in whom an intra-articular fracture of the radial head had been treated with open reduction and internal fixation were evaluated at an average of forty-eight months after injury. Thirty patients had a Mason Type-2 (partial articular) fracture, and twenty-six had a Mason Type-3 (complete articular) fracture. Twenty-seven of the fifty-six fractures were associated with a fracture-dislocation of the forearm or elbow or an injury of the medial collateral ligament. Fifteen of the thirty Type-2 fractures were comminuted. Fourteen of the twenty-six Type-3 fractures consisted of more than three fragments, and twelve consisted of two or three fragments. The result at the final evaluation was judged to be unsatisfactory when there was early failure of fixation or nonunion requiring a second operation to excise the radial head, <100 degrees of forearm rotation, or a fair or poor rating according to the system of Broberg and Morrey.

RESULTS

The result was unsatisfactory for four of the fifteen patients with a comminuted Mason Type-2 fracture of the radial head; all four fractures had been associated with a fracture-dislocation of the forearm or elbow, and all four patients recovered <100 degrees of forearm rotation. Thirteen of the fourteen patients with a Mason Type-3 comminuted fracture with more than three articular fragments had an unsatisfactory result. In contrast, all fifteen patients with an isolated, noncomminuted Type-2 fracture had a satisfactory result. Of the twelve patients with a Type-3 fracture that split the radial head into two or three simple fragments, none had early failure, one had nonunion, and all had an arc of forearm rotation of > or =100 degrees.

CONCLUSIONS

Although current implants and techniques for internal fixation of small articular fractures have made it possible to repair most fractures of the radial head, our data suggest that open reduction and internal fixation is best reserved for minimally comminuted fractures with three or fewer articular fragments. Associated fracture-dislocation of the elbow or forearm may also compromise the long-term result of radial head repair, especially with regard to restoration of forearm rotation.

Standard surgical protocol to treat elbow dislocations with radial head and coronoid fractures

BACKGROUND

The results of elbow dislocations with associated radial head and coronoid fractures are often poor because of recurrent instability and stiffness from prolonged immobilization. We managed these injuries with a standard surgical protocol, postulating that early intervention, stable fixation, and repair would provide sufficient stability to allow motion at seven to ten days postoperatively and enhance functional outcome.

METHODS

We retrospectively reviewed the results of this treatment performed, at two university-affiliated teaching hospitals, in thirty-six consecutive patients (thirty-six elbows) with an elbow dislocation and an associated fracture of both the radial head and the coronoid process. Our surgical protocol included fixation or replacement of the radial head, fixation of the coronoid fracture if possible, repair of associated capsular and lateral ligamentous injuries, and in selected cases repair of the medial collateral ligament and/or adjuvant hinged external fixation. Patients were evaluated both radiographically and with a clinical examination at the time of the latest follow-up.

RESULTS

At a mean of thirty-four months postoperatively, the flexion-extension arc of the elbow averaged 112 degrees +/- 11 degrees and forearm rotation averaged 136 degrees +/- 16 degrees. The mean Mayo Elbow Performance Score was 88 points (range, 45 to 100 points), which corresponded to fifteen excellent results, thirteen good results, seven fair results, and one poor result. Concentric stability was restored to thirty-four elbows. Eight patients had complications requiring a reoperation: two had a synostosis; one, recurrent instability; four, hardware removal and elbow release; and one, a wound infection.

CONCLUSIONS

Use of our surgical protocol for elbow dislocations with associated radial head and coronoid fractures restored sufficient elbow stability to allow early motion postoperatively, enhancing the functional outcome. We recommend early operative repair with a standard protocol for these injuries.

Osteosynthesis of distal radial fractures with a volar locking screw plate system

We developed a locking screw plate system for the stabilisation of distal radial fractures, which can be inserted through a standard volar approach and in which the locking mechanism allows early post-operative mobilisation. Forty-nine patients with 50 fractures underwent surgical treatment; 66% were type C fractures. The mean follow-up was 26 months. According to the scores of Gartland and Werley and Green and O'Brien, 92% and 68% respectively had an excellent or good outcome; 46% were radiologically identical to the uninjured side and in 42% the reduction remained unchanged after 2 years. The most frequent complication was rupture of the flexor pollicis longus tendon, which occurred in six cases (12%) at a mean of 10 months after operation.

Arthroplasty with a metal radial head for unreconstructible fractures of the radial head

BACKGROUND

Treatment of unreconstructible comminuted fractures of the radial head remains controversial. There is limited information on the outcome of management of these injuries with arthroplasty with a metal radial head implant.

METHODS

The functional outcomes of arthroplasties with a metal radial head implant for the treatment of twenty-five displaced, unreconstructible fractures of the radial head in twenty-four consecutive patients (mean age, fifty-four years) were evaluated at a mean of thirty-nine months (minimum, two years). There were ten Mason type-III and fifteen Mason-Johnston type-IV injuries. Two of these injuries were isolated, and twenty-three were associated with other elbow fractures and/or ligamentous injuries.

RESULTS

At the time of follow-up, Short Form-36 (SF-36) summary scores suggested that overall health-related quality of life was within the normal range (physical component = 47 +/- 10, and mental component = 49 +/- 13). Other outcome scales indicated mild disability of the upper extremity (Disabilities of the Arm, Shoulder and Hand score = 17 +/- 19), wrist (Patient-Rated Wrist Evaluation score = 17 +/- 21 and Wrist Outcome Score = 60 +/- 10), and elbow (Mayo Elbow Performance Index = 80 +/- 16). According to the Mayo Elbow Performance Index, three results were graded as poor; five, as fair; and seventeen, as good or excellent. The poor and fair outcomes were associated with concomitant injury in two patients, a history of a psychiatric disorder in three, comorbidity in two, a Workers' Compensation claim in two, and litigation in one. Subjective patient satisfaction averaged 9.2 on a scale of 1 to 10. Elbow flexion of the injured extremity averaged 140 degrees +/- 9 degrees; extension, -8 degrees +/- 7 degrees; pronation, 78 degrees +/- 9 degrees; and supination, 68 degrees +/- 10 degrees. A significant loss of elbow flexion and extension and of forearm supination occurred in the affected extremity, which also had significantly less strength of isometric forearm pronation (17%) and supination (18%) as well as significantly less grip strength (p < 0.05). Asymptomatic bone lucencies surrounded the stem of the implant in seventeen of the twenty-five elbows. Valgus stability was restored, and proximal radial migration did not occur. Complications, all of which resolved, included one complex regional pain syndrome, one ulnar neuropathy, one posterior interosseous nerve palsy, one episode of elbow stiffness, and one wound infection.

CONCLUSIONS

Patients treated with a metal radial head implant for a severely comminuted radial head fracture will have mild-to-moderate impairment of the physical capability of the elbow and wrist. At the time of short-term follow-up, arthroplasty with a metal radial head implant was found to have been a safe and effective treatment option for patients with an unreconstructible radial head fracture; however, long-term follow-up is still needed.

Use of injectable calcium phosphate cement for fracture fixation: a review

Injectable osteoconductive calcium phosphate cements have been introduced as an adjunct to internal fixation for treating selected fractures. These cements harden without producing much heat, develop compressive strength, and are remodeled slowly in vivo. The main purpose of the cement is to fill voids in metaphyseal bone, thereby reducing the need for bone graft, but cements also may improve the holding strength around metal devices in osteoporotic bone. Several bioactive cements are being developed. One of these cements, Skeletal Repair System, is available in Europe and has been approved by the United States Food and Drug Administration for use in selected distal radius fractures. Cadaveric studies have shown that using Skeletal Repair System cement with conventional metal fixation in certain fractures of the distal radius, tibial plateau, proximal femur, and calcaneus can produce better stability, stiffness, and strength than metal fixation alone. Early clinical results have shown reduced time to full weightbearing when cement has been used for augmentation of tibial plateau and calcaneal fractures, more rapid gain of strength and range of motion when used in distal radius fractures, and improved stability in certain hip fractures. Bioactive cements in general also may prove useful in vertebroplasty.

An anatomic and mechanical study of the interosseous membrane of the forearm: pathomechanics of proximal migration of the radius

The interosseous membrane of the forearm of 12 fresh cadaver specimens was studied anatomically and mechanically to better understand its role in stabilization of the radius after radial head excision. A central band of ligamentous tissue, approximately twice the thickness of the membrane on either side was identified in all specimens. Mechanical studies determined the relative contribution to longitudinal stiffness of the forearm. The central band was responsible for 71% of the longitudinal stiffness of the interosseous membrane after radial head excision. The contribution of the triangular fibrocartilage complex was 8%. Silicone radial head implants were much less stiff than the intact interosseous membrane. Injury to the central band of the interosseous membrane may be crucial to the development of proximal migration of the radius after radial head excision.

Prospective multicenter trial of a plate for dorsal fixation of distal radius fractures

A new plate designed specifically to address complex wrist pathology was used for the internal fixation of 22 complex fractures of the distal radius in 22 patients in a prospective multicenter trial. The majority of fractures were group C2- and C3-type fractures according to the Comprehensive Classification of Fractures. No plate failures, loss of reduction, nonunions, or infections occurred. Within the average follow-up time of 14 months, the functional results (including an average motion of 76% and an average grip strength of 56% of the contralateral side) were comparable to those reported for similar fractures in previous investigations. Five patients had irritation of the tendons in the second dorsal compartment. This trial serves both as a verification of the safety and efficacy of this distal radius plate as well as a demonstration of its utility in the treatment of complex fractures of the distal radius.

Displaced intra-articular fractures of the distal aspect of the radius. Long-term results in young adults after open reduction and internal fixation

The purpose of this retrospective study was to determine the long-term functional and radiographic outcomes in a series of young adults (less than forty-five years old) in whom an acute displaced intra-articular fracture of the distal aspect of the radius had been treated with operative reduction and stabilization. Twenty-six fractures in twenty-six patients met the initial inclusion criteria for the study. Twenty-one patients returned for a physical examination, imaging (plain radiographs and computerized tomography scans), and completion of a validated musculoskeletal function assessment questionnaire at a minimum of 5.5 years. The physical examinations were performed by the same observer, who was not involved in the initial care of the patients. The plain radiographs and computerized tomography scans were assessed in a blinded fashion by two independent observers who measured the radiographic parameters with standardized methods. At an average of 7.1 years, osteoarthrosis of the radiocarpal joint was evident on the plain radiographs and computerized tomography scans of sixteen (76 per cent) of the twenty-one wrists. A strong association was found between the development of osteoarthrosis of the radiocarpal joint and residual displacement of articular fragments at the time of osseous union (p < 0.01). However, the functional status at the time of the most recent follow-up, as determined by physical examination and on the basis of the responses on the questionnaire, did not correlate with the magnitude of the residual step and gap displacement at the time of fracture-healing. All patients had a good or excellent functional outcome irrespective of radiographic evidence of osteoarthrosis of the radiocarpal or the distal radio-ulnar joint or non-union of the ulnar styloid process. It appears prudent therefore to base the indications for salvage operative procedures on the presence of severe symptoms or a loss of function rather than on radiographic evidence of osteoarthrosis of the radiocarpal joint.

Coronoid process and radial head as posterolateral rotatory stabilizers of the elbow

BACKGROUND

The purpose of this study was to evaluate the role of the radial head and the coronoid process as posterolateral rotatory stabilizers of the elbow and to determine the stabilizing effect of radial head replacement and coronoid reconstruction.

METHODS

The posterolateral rotatory displacement of the ulna was measured after application of a valgus and supinating torque (1). in seven intact elbows, (2). after radial head excision, (3). after sequential resection of the coronoid process, (4). after subsequent insertion of each of two different types of metal radial head prostheses (a rigid implant and a bipolar implant with a floating cup), and (5). after subsequent reconstruction of the coronoid with each of two different techniques in the same cadaveric elbow.

RESULTS

The posterolateral rotatory laxity averaged 5.4 degrees in the intact elbows. The surgical approach used in this study insignificantly increased the mean laxity to 9 degrees. Excision of the radial head in an elbow with intact collateral ligaments caused a mean posterolateral rotatory laxity of 18.6 degrees (p < 0.0001). Additional removal of 30% of the height of the coronoid fully destabilized the elbows, always resulting in ulnohumeral dislocation despite intact ligaments. Implantation of a rigid radial head prosthesis stabilized the elbows. However, a mean laxity of 16.9 degrees persisted after insertion of a floating prosthesis (p < 0.0001). The elbows with a defect of 50% or 70% of the coronoid, loss of the radial head, and intact ligaments could not be stabilized by radial head replacement alone, but additional coronoid reconstruction restored stability.

CONCLUSIONS

The results of this study suggest that the coronoid and the radial head contribute significantly to posterolateral rotatory stability.

Forearm and distal radius fractures in children

Pediatric forearm and distal radius fractures are common injuries. Resultant deformities are usually a product of indirect trauma involving angular loading combined with rotational displacement. Fractures are classified by location, completeness, angular and rotational deformity, and fragment displacement. Successful outcomes are based on restoration of adequate pronation and supination and, to a lesser degree, acceptable cosmesis. When several important concepts are kept in mind, these goals are usually met with conservative treatment by reduction and immobilization. Greenstick fractures are reduced by rotating the forearm such that the palm is directed toward the fracture apex. Complete fractures are manipulated and reduced with traction and rotation; extremities are then immobilized in well-molded plaster casts until healing, which usually takes about 6 weeks. Radiographs should be obtained between 1 and 2 weeks after initial reduction to detect early angulation. In fractures in any level in children less than 9 years of age, complete displacement, 15 degrees of angulation, and 45 degrees of malrotation are acceptable. In children 9 years of age or older, 30 degrees of malrotation is acceptable, with 10 degrees of angulation for proximal fractures and 15 degrees for more distal fractures. Complete bayonet apposition is acceptable, especially for distal radius fractures, as long as angulation does not exceed 20 degrees and 2 years of growth remains. Operative intervention is used when the fracture is open and when acceptable alignment cannot be achieved or maintained. Single-bone intramedullary fixation has proven useful.

Radiographic evaluation of osseous displacement following intra-articular fractures of the distal radius: reliability of plain radiography versus computed tomography

This study evaluated the reliability of plain radiography versus computed tomography (CT) for the measurement of small (< 5 mm) intra-articular displacements of distal radius fracture fragments. The plain radiographs and CT scans of 19 acute intra-articular distal radius fractures were used by 5 independent observers, using 2 standardized techniques, to quantify incongruity of the articular surface in a blinded and randomized fashion. Repeat measurements were performed by the same observers 2-4 weeks later, allowing determination of intraclass correlation coefficients (ICC) as a measure of intraobserver and interobserver agreement. The average maximum gap displacement on plain radiographs was 2.1 mm (range, 0.0-15.0 mm, lateral view) and on CT images was 4.9 mm (range, 0.7-17.3 mm, axial view). The average maximum step displacement on plain radiographs was 0.9 mm (range, 0.0-6.4 mm, lateral view) and on CT images was 1.2 mm (range, 0.0-6.0 mm, sagittal view). More reproducible values determining step and gap displacement were obtained when the arc method of measurement was used on CT scans (ICC values, .69-.97) as compared to the longitudinal axis method for plain radiographs (ICC values, .30-.50). For measured displacements of 2 mm or more, our data demonstrated poor correlation between measurements made on CT images and those made on plain radiographs (gap or step displacement > 2 mm, K = 0.21; step displacement > 2 mm, K = 0.21). Thirty percent of measurements from plain radiographs significantly underestimated or overestimated displacement compared to CT scan measurements. From these data, we conclude that CT scanning data, using the arc method of measurement, are more reliable for quantifying articular surface incongruities of the distal radius than are plain radiography measurements.

The functional outcome with metallic radial head implants in the treatment of unstable elbow fractures: a long-term review

BACKGROUND

A long-term review of metal prosthetic radial head replacement in patients with radial head fractures associated with gross instability of the elbow has been performed.

METHOD

Twenty patients were reviewed using a modified Mayo Clinic functional rating index system. The mean follow-up was 12.1 years, with a range from 6 to 29 years.

RESULTS

Results were excellent in 12 patients, good in 4 patients, fair in 2 patients, and poor in 2 patients. A metal radial head replacement restored elbow stability when fracture of the radial head occurred in combination with dislocation of the elbow, rupture of the medial collateral ligament, fracture of the proximal ulna, and/or fracture of the coronoid process.

CONCLUSION

We conclude that a metal radial head prosthesis has select indications. We advocate its use when the radial head cannot be reconstructed in the setting of a clinically unstable elbow. Results suggest that it functions well on a long-term basis.

Current concepts in volar fixed-angle fixation of unstable distal radius fractures

We present new developments in the volar treatment of unstable distal radius fractures in adults. New perspectives on the anatomy of the wrist, the watershed line on the volar radius and the usefulness of the pronator fossa are presented and these help to avoid flexor and extensor tendon disturbance when using a volar approach. Other new insights on the bony anatomy of the distal end of the radius are discussed, which are important in improving the quality of fracture fixation, including the benefits of constructing a precise fixed-angle scaffold underneath the articular surface in order to stabilize it. A volar fixed-angle plate must support the dorsal, central and volar aspects of the subchondral bone in order to stabilize the most complex fractures. Awareness of the anatomy of blood supply to the distal radius: the dorsal retinaculum that feeds the distal fragments and the blood supply to the diaphysis through branches of the anterior interosseous artery is necessary to maximize healing potential and avoid complications. Volar fixed-angle plates need to withstand very high forces during rehabilitation, the magnitude of these forces are up to five times the loads applied on the hand.

LEVEL OF EVIDENCE

Level V (expert opinion).

The effect of time to definitive treatment on the rate of nonunion and infection in open fractures

OBJECTIVES

To determine the association between time to definitive surgical management and the rates of nonunion and infection in open fractures resulting from blunt trauma. To determine the association of other clinical determinants with these same adverse events.

DESIGN

Retrospective review of a consecutive series of open long bone fractures.

SETTING

Referral trauma center with transport times often extending beyond eight hours from the time of injury.

PATIENTS

A total of 227 skeletally mature patients with 241 open long bone fractures were treated between January 1996 and December 1998; 215 fractures were available for review at a minimum of twelve months postinjury.

INTERVENTION

Medical charts of all patients were reviewed using a standardized data collection form. All available records and radiograph reports were inspected. All cases were followed to clinical and radiographic union of the fracture or until a definitive procedure for nonunion or deep infection was carried out.

MAIN OUTCOME MEASURES

Occurrence of deep infections or nonunions after fracture treatment.

RESULTS

The mean time to definitive treatment was eight hours and twenty-five minutes (range 1 hour 35 minutes to 30 hours 40 minutes). Forty patients went on to nonunion, and twenty developed a deep infection. In the final multivariate regression model, time was not a significant factor in predicting either nonunion or infection (p > 0.05). The strongest determinants for nonunion were found to be presence of infection and grade of injury (p < 0.05). The strongest predictors for the development of a deep infection were fracture grade and a lower extremity fracture (p < 0.05).

CONCLUSIONS

The risk of developing an adverse outcome was not increased by aggressive debridement/lavage and definitive fixation up to thirteen hours from the time of injury when early prophylactic antibiotic administration and open fracture first aid were instituted.

Arthroscopic diagnosis of intra-articular soft tissue injuries associated with distal radial fractures

Arthroscopy was used to assess the soft tissue injuries associated with distal radial fractures in 118 acute intra- and extra-articular fractures. The triangular fibrocartilage complex (TFCC) was torn in 46 of 118 patients--in 35% of intra-articular fractures and in 53% of extra-articular fractures. No correlation between ulnar styloid fractures and TFCC injuries could be found. Scapholunate (SL) ligament injuries with instability were present in 21.5% of intra-articular fractures and in 6.7% of extra-articular fractures. Lunotriquetral (LT) ligament injuries with instability were present in 6.7% of intra-articular fractures. and in 13.3% of extra-articular fractures. Combined SL and LT injuries were present in 5.6% of intra-articular fracture. Preoperative radiographs correlated with TFCC injury. Patients with TFCC tears had greater shortening and dorsal angulation on the preoperative radiographs. Preoperative radiographs had no predictive value for interosseous ligament injury. Ligamentous injuries are commonly associated with both intra-articular and extra-articular distal radial fractures.

The treatment of unstable distal radius fractures with volar fixation

Stable internal fixation and early motion has not been routinely available for distal radius fractures. Difficulties with the dorsal approach discourage surgeons from internally fixing the most common fracture types. The introduction of a new volar plate with subchondral support fixation allows the treatment of most distal radius fractures with stable internal fixation and early motion while avoiding the complications inherent in the dorsal approach.

Peripheral tears of the triangular fibrocartilage complex cause distal radioulnar joint instability after distal radial fractures

The aim of this prospective study was to determine whether peripheral tears of the triangular fibrocartilage complex (TFCC) in patients younger than the osteoporotic age (males,<60 years; females, <50 years) were related to chronic distal radioulnar joint (DRUJ) instability. Fifty-one patients (27 women) with displaced distal radial fractures were included in the study. The median age was 41 years (range, 20-57 years). Arthroscopy at the time of fracture showed complete or partial TFCC tears in 43 patients (24 had only peripheral tears, 10 had only central perforations, and 9 had combined tears). The 1-year (range, 11-27 months) follow-up period included an interview, physical examination, and radiographic evaluation. Ten of the 11 patients with complete peripheral TFCC tears had DRUJ instability at the follow-up examination compared with 7 of the 32 patients with only partial or no peripheral tears. Patients with instability of the DRUJ had a worse Gartland and Werley wrist score. Instability was not associated with any radiographic finding either at the time of fracture or at the follow-up examination. Initial fracture or nonunion of the styloid was even slightly more common in stable patients.

Treatment of displaced articular fractures of the radius

Forty patients with articular fractures of the distal radius in which anatomic reduction of the joint surface could not be obtained by closed manipulation or by ligamentotaxis with external fixators had a combination of percutaneous and/or open reduction techniques to restore articular congruity. X-ray films taken after treatment with an average follow-up of 4 years showed satisfactory extraarticular alignment in 85% of the cases, and 37 (92.5%) patients demonstrated an articular step-off of 1 mm or less at late follow-up examination. Radiographic evidence of radiocarpal arthritis was present in 5% of the cases at follow-up examination.