Radial Head Fracture

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CASE SUMMARY 1 “RADIAL HEAD FRACTURE”

INTRODUCTION Radial head fracture may represent an isolated intra-articular fracture or combined complex injury involving the ulnar collateral, interosseous or the distal radioulnar ligament. Careful and thorough assessment is needed to differentiate these two forms of injuries. The main goal of its treatment is to maintain a good elbow function and thus to

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retain an adequate elbow motion and joint stability. With a proper choice of treatment and rehabilitation program, this type of fractures can be managed adequately with good functional outcome. CASE REPORT (RN 833864) L.K.W., a 21-year-old male was admitted on the 23 rd January 2002 with a history of fall from a flight of stairs approximately 10 feet high. His left elbow directly hit the ground at the end of the fall. The patient has no significant past medical or surgical histories. He works as an air-conditioner mechanic and is a right-handed person. Examination revealed a swollen left elbow with tenderness over the lateral side of the joint. No wounds were noted on the left elbow region. There was reduced range of motion in all directions. The pulses were palpable distally and there was no neurological deficits noted. The left elbow AP and lateral radiographs revealed fracture of the left radial head with displacement. The wrist radiographs showed that the distal radioulnar joint was intact. A diagnosis of fracture of the left radial head (Mason type II) was made and the patient was admitted for open reduction and screw fixation. On admission the elbow was put on a backslab in the functional position and analgesics were given. He underwent an open reduction and screw fixation of the fracture on the 30 th of January 2002. After given a supraclavicular block, the upper limb was cleaned and draped. Exsanguination was followed by torniquet inflation up to 250 mmHg. The Kocher’s approach was used and the interval between the anconeus and the extensor carpi ulnaris entered. The annular ligament was noted to be intact and partial resection was done for better exposure of the radial head. The radial head was noted to be fractured into three pieces and there was also a chondral fracture fragment involving the capitellar cartilage (~ 1 cm diameter) which was impacted into the radial head fracture site. The impacted cartilage was removed and the joint was washed and cleared from any debris. The radial head was then fixed with two 2.0 mm cortical screws inserted under lag screw principles. The screws were inserted in the non-articulating area of the radial head (see DISCUSSION on ‘The safe zone”). Post-screw fixation assessment for stability of the

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fixation as well as the elbow joint was performed and all the ligaments were noted to be intact. The area was again washed with saline. The annular ligament and fascia was repaired with Dexon 3/0. Skin was closed with Dafilon 4/0 sutures. Post-operatively the left upper limb was elevated on a drip stand to avoid excessive swelling and edema. Post-operatively, the check radiograph was acceptable with stable reduction of the fracture fragments and the patient was discharged well. At 2 weeks post-op, the wound was healing, sutures were removed and passive elbow range of motion exercise was started. At 6 weeks the patient had full extension, supination and pronation of the left elbow with a slightly limited flexion. Physiotherapy was continued further. At 11 weeks post-op, the elbow range of motion was full in all directions and radiographs showed that the screw fixation is stable and the fracture line disappearing. The patient was allowed to go back to work and was discharged from follow-up. DISCUSSION Radial head and neck fractures represent approximately 1.7 to 5.4 % of all fractures. Radial head fractures alone account for about 1/3 of all elbow fractures and are involved in approximately 20 % of elbow trauma cases (Caputo et al. 1998). Combined with olecranon fractures, they account for more than one-half of the fractures at this site (Morrey et al. 1995). 10% of cases of elbow dislocations had been found to be associated with radial head fractures (Kupersmith et al. 2001). The head of radius is cylindrical in shape and is covered by hyaline cartilage. This cartilage layer is somewhat wider, whitish glistening in the area which articulates with the radial notch of the ulna (Caputo et al. 1998), making it easier to identify intra-operatively in the process of recognizing ‘the safe zone’ – which is the non-articulating area of the head (a safe place to insert/place implants) that is more yellowish and has a thinner cartilaginous layer. The head is palpable in the depression behind the lateral side of the extended elbow, where it can be felt rotating in pronation-supination movements. The upper surface of the radial head is spherically concave to fit the capitulum.

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The head is held on to the radial notch of the ulna by the annular ligament, which tapers at its lower end to hold the neck of radius. The superior radioulnar joint is a uniaxial synovial pivot joint between the radial head and the annular ligament. The elbow joint capsule and the triangular lateral collateral ligament are attached to the annular ligament and both the elbow and the superior radioulnar joint share the same synovial membrane. The non-articulating portion of the radial head is the most common area to be fractured as it lacks strong subchondral osseous support (Morrey et al. 1995). This is beneficial in the sense that it allows easier fracture fixation within the safe zone of the radial head. Elbow joint stability is maintained by the ligaments (mainly the medial and lateral collateral ligaments), the bones and the muscles which traverse the joint. The medial collateral ligament consists of the anterior band (the anterior medial collateral ligament, AMCL), the posterior band (PMCL) and the transverse band. Out of these three, the AMCL is the main ligament contributing to the strength of the medial collateral ligament. The lateral collateral ligament is also triangular in shape with its apex attached to the lateral humeral epicondyle and the base fused to the annular ligament. Morrey et al. (1991) found out that the MCL acts as the primary constraint of the elbow joint with the radial head as the secondary constraint of the elbow joint. They found out that absence of the radial head does not significantly alter the three dimensional characteristics of motion in the elbow joint, provided that the MCL is intact. The most common mechanism of injury is fall onto an outstretched hand with the elbow extended and the forearm pronated. This causes transmission of axial load across the radiocapitellar joint and fracture of the radial head. Clinically the patient will have local swelling and tenderness over the head of radius. There is reduced movement of the elbow. Presence of echymosis along the medial elbow in a patient with radial head fracture (without ulnar bone injury) is pathognomonic for a medial collateral injury (Kupersmith et al. 2001) as the radial head is anatomically isolated from the medial side by muscle planes and fascia.

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It is necessary to assess the elbow function when examining the patient. Morrey et al. 1995 advocate the use of local anaesthetics that is injected into the elbow joint before examination is performed. This is preceded by joint aspiration, allowing 2 benefits: (i) Aspiration of the joint relieves the pressure-increase due to haemarthrosis. (ii) Infiltration of local anaesthetics provides temporary pain relief to allow proper examination of the elbow joint. Examination is performed to assess the ligaments (in particular the medial collateral and the distal radioulnar joint); and the range of motion of the elbow to exclude bony block to full movement. Standard AP and lateral radiographs of the elbow should be obtained upon suspicion of a radial head fracture. A valgus-stress view usually helps in the diagnosis of medial collateral ligament involvement (medial joint space widening). The radial headcapitellum view may also be helpful (Kupersmith et al. 2001) Treatment of radial head fractures was first described by Thomas in 1905. Operative management at the time was limited to simple excision. Carstam first mentioned regarding open reduction and internal fixation in 1950 and since his published result, ORIF has become more popular for certain type of fractures of the radial head (quoted from Furry et al. 1998). Currently, treatment of radial head fractures remains controversial and frequently guided by the severity of the fracture as classified by Mason.

Mason’s Classification of radial head fracture is the most widely used and accepted classification system. Table 1 : Modified Mason’s Classification for Radial Head Fractures ( Chapman’s Textbook of Orthopedic Surgery)

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TYPE

CHARACTERISTICS

I II

Undisplaced fracture Marginal fracture with displacement; involvement of more than 30%

III

of the head Comminuted fracture involving the entire radial head

IV

Fracture of radial head with associated elbow dislocation (Modified by Johnston 1962)

Morrey et al. (1995) practically classified this fracture into simple and complex fractures. Simple fractures are those without an associated injury. These fractures include those of type I, II and III of the Mason’s classification. Mason’s type IV injury is included into the complex group. Conservative treatment remains the choice of treatment for most type I and some type II fractures of the radial head. Treatment consists of early motion, usually within several days or as early as pain allows. This has been shown to prevent stiffness and loss of terminal extension (Kuppersmith et al. 2001). Early motion in type I fractures was associated with 90 percent chance of a good outcome, even though complications can still occur, the most common being non-union (Morrey et al. 1995). Morrey et al. (1995) also suggested that type II fractures that show at least 20 to 140 degrees of flexion and 70 degrees of forearm rotation in both directions (supination and pronation) are amenable for non-operative treatment. However, in these cases immobilization should be carried out longer (for 2 to 3 weeks) before active range of motion can be started. Indications for open reduction and internal fixation include mechanical block of motion, fracture where greater than 1/3 of the articular surface is involved, displacement of more than 2 to 3 mm of the fracture fragment and more than 2 to 3 mm of articular depression. Other indications are lesions involving the capitellar cartilage, an associated proximal ulnar fracture, injury to the medial collateral ligament or to the distal radio-ulnar joint (Essex-Lopresti injury). In this particular patient, the indications to perform ORIF are involvement of more than 1/3 of the articular surface and also capitellar cartilage

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lesion. Contraindications to ORIF include older age patient, an underlying osteoarthritis and injury to the bony capitellum. Studies have shown that ORIF is the treatment of choice for Mason type II fractures. King et al. (1991) treated 14 elbows with type II injury and revealed that all patients showed good or excellent results after an average of 32 months of follow-up. Khalfayan et al. (1992) reviewed 29 cases of Mason type II fractures (10 were treated by ORIF, 19 conservatively) and found out that patients treated conservatively have higher incidence of pain, functional limitations, loss of strength and radiographic evidence of arthritis. The same group also showed higher incidence of articular depression, displacement and joint narrowing radiographically. The use of fibrin adhesive seal was advocated by Arce et al. (1995) when they fixed 15 type II fractures with the Fibrin Adhesive System (FAS). After operation, the elbows were immobilized for a mean of 2.3 weeks. On follow-up (ranged from 20 to 48 months), no patient had any pain, 4 patients showed limitation of full extension while one patient showed limitation of supination. The reconstruction was, in all cases, practically anatomical by radiographic evaluation. However, they advised against the use of FAS for comminuted radial head fractures of more than two fragments. Boulas and Morrey (1998) studied 36 fractures (type not mentioned) treated in 4 different ways - ORIF, excision, silastic head replacement and conservative. They found out that the grip strength of patients treated with ORIF was significantly better compared to other groups even though all groups showed comparative results in Clinical Performance Index and elbow motions. Furry et al. (1998) concluded that fractures of the radial head which were treated by ORIF had a low reported incidence of avascular necrosis and non-union. He suggested that the radial head should be preserved when technically feasible and replaced if otherwise. O’Driscoll et al. (2000) suggested that small fragments not suitable for screw fixation can be fixed with threaded Kirschner wires as an alternative. Smooth K-wires should be avoided as they have a tendency to migrate post-operatively.

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In this patient, the fracture was a three part fracture and was noted to be displaced with involvement of more than 30% of the circumference of the head which puts it into the Mason type II fracture. The fragments were noted to be reducible and stable to be fixed with 2 screws inserted under lag screw principles. As suggested by Furry et al. (1998), fractures noted intra-operatively to be feasible for ORIF should be treated as such. It was also noted during operation that the ligaments were not involved in the injury. This carries a good prognosis in the context of union of the fracture as studied by Ring and Jupiter (2000). The main danger in exposure and fixation of radial head fractures is possibility of the posterior interosseus nerve (PIN) injury. The close proximity of this nerve to the operative field makes it vulnerable to iatrogenic injury and the resultant paralysis of the muscles of the extensor compartment is one of the dreaded complications in this type of surgery. In the classical Kocher’s approach, the plane between the anconeus and the extensor carpi ulnaris, ECU is utilized. Incision is made starting from the posterior surface of the lateral humeral epicondyle and this is continued longitudinally about 5 cm down to the level of the lower aspect of the radial head. The interval between the anconeus (supplied by the radial nerve) and the extensor carpi ulnaris, ECU (supplied by the PIN) is identified and separated using a retractor. The forearm is fully pronated to move the PIN away from the operative field. Morrey et al. (1993) suggested that the capsule should be divided anterior to the lateral ligamentous complex that attaches to the ulna. Witt and Kamineni (1998) studied 21 cadaver-elbows and observed that the first branches of the PIN at risk (in the posterolateral approach) were situated about 6 cm from the articular surface of the radial head. This corresponds to the distal aspect of the bicipital tuberosity on the radius. Diliberti et al. (2000) found out that for the posterolateral approach of the lateral aspect of the radial head, the PIN is safest with the forearm in pronation. Placement of implant on the non-articulating portion of the radial head (the safe zone) is crucial as it prevents hardware impingement during pronation and supination. This zone can be recognized by the:-

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(1) Color and thickness of the cartilage (2) Smith-Hotchkiss technique (3) Caputo technique Smith and Hotchkiss (1996) described a method for localizing this safe zone by marking the side of the radial head in various positions of rotation of the forearm. The limitation of this method is that it is only applicable for lateral approach and requires full forearm rotation (Andrew et al. 1998). Caputo et al. (1998) studied 24 elbows in 12 cadavers and described that the arc of the safe zone encompassed the 90 o angle between the radial styloid and Lister’s tubercle, and this findings are constant in all three surgical approaches (anterior, lateral and posterolateral). Treatment of type III fractures remain a challenge to surgeons. Decision has to be made whether to perform an open reduction and internal fixation or to remove the head completely with or without radial head prosthetic replacement. King et. al. (1991) internally fixed six type III radial head fractures in a study comparing type II and III fractures. Type II showed 100% good to excellent results while type III only showed 33% good to excellent results. They suggested that the degree of comminution should be evaluated radiographically and intra-operatively, and the decision whether to reconstruct or excise the radial head depends on whether anatomic reduction is achievable or not. Morrey et al. (1995) did not recommend ORIF for type III fractures, as it is a difficult procedure to perform. Furthermore, approximately 10% of type III fractures are associated with an elbow dislocation, a combination that constitutes one of the most difficult management problems. Ring and Jupiter (2000), in a retrospective review of 73 patients, found out that ORIF of complex, comminuted fractures of the radial head may lead to nonunion in upwards of 13% of patients. On the contrary, Esser et al. (1995) had seven excellent and two good results out of nine type III fractures fixed with using AO screws, Herbert screws and / or mini AO T-plates. However the number of patients in this study is quite small. The controversial issue on the best treatment option for non-reconstructable radial

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head fractures remains. First comes the question of stability following radial head excision. It has been shown that, with excision alone (with the ligaments intact), the radius migrates proximally 2.6 times farther than an intact radius under a given mechanical load (Furry et al. 1998). Studies demonstrated that with removal of the radial head alone, proximal radial migration is 0.4 mm. Combined with interosseous membrane injury, the migration increased to 4.4 mm. Radial head resection with TFCC division causes 2.2 mm of proximal radial migration. Combining all three, the migration increased to 16.8 mm (quoted from Bernstein et al. 2000). Morrey et al. (1991) found out that the radial head plays an important stabilizing role in resisting valgus stress only when the medial collateral ligament is disrupted. Therefore radial head excision alone in these circumstances will not suffice with regards to the stability of the elbow to valgus force and replacement of the head should be done. Shepard et al. (2001) in a cadaveric study of the effects of radial head excision on the load-sharing capacity of the radius and ulna found out that radial shortening causes slackening of the interosseous membrane, thereby negating its ability to transmit load across the forearm. The resultant ulnar-positive wrist created a shift of applied load from the distal radius to the distal ulna and thus increased distal ulnar loading (load is increased approximately 10% with every millimeter of radial shortening). His study also concluded that damage of the interosseous membrane will shift nearly the entire applied wrist force to the ulna. Next comes the issue of whether to remove the head completely or to replace it with prosthesis. Furry et al. (1998) concluded that excision with radial head replacement is useful for those fractures with associated ligamentous injury as it provides temporary or permanent lateral stability (for associated MCL injury) and axial stability (for interosseous or distal radioulnar joint injury). He also suggested that multi-fragmentary fractures not amenable for ORIF should be replaced with prosthesis, especially in young patients. Furthermore, elderly patients and those patients who are very ill or polytraumatized that could not tolerate prolonged anaesthesia should benefit from radial head replacement which can often be performed with less operative time compared to ORIF.

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Radial head excision alone can be performed to treat non-reconstructable radial head fractures, provided that the ligaments responsible for elbow stability are intact. Wallenbock and Potsch (1997) retrospectively studied 23 patients with radial head resection without implant insertion (average 17 years follow-up) and found out that all patients had very good to satisfactory outcome without a single case of poor outcome. However it was not mentioned whether these patients had associated ligamentous injury or not. Furry et al. (1998) and Moro et al. (2001) mentioned that radial head excision may lead to complications such as pain, instability, new-bone formation around the resection site, proximal radial migration and cubitus valgus. Prevention of these complications can be achieved by replacing the head with prosthesis. Different prosthetic materials have been used and studied. Acrylic, siliconerubber, Vitallium, cobalt-chromium and titanium had been used and described in literatures. Vitallium prosthesis was studied by Knight et al. (1993) and they found out that the metal’s rigidity improves elbow stability when there has been gross soft tissue tearing. This implant also has a low incidence of symptomatic loosening and erosion. The use of this metal avoids some disadvantages experienced with silicone-rubber heads (sensitivity reactions, implant fractures and capitellar osteopenia from reduced load transfer). It also helps to share and balance the forces acting across the elbow and allows earlier mobilization. Morrey (1995) seemed to agree with Knight et al. (1993) when he mentioned that a metal implant is a viable solution when radial head resection is indicated and the elbow is unstable. Silicone-rubber implants had been all but abandoned in the United States (Morrey 1995). This is due to complications associated with this implant. Other than those already mentioned above, mechanical studies had shown that silicone-rubber allows proximal radial migration 2.3 times farther than an intact radial head. Morrey (1995) found out that silicone-rubber implants had no functional advantage over other types of prostheses in the context of inhibiting proximal radial migration after radial head excision.

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Judet et al. (1996) reported a series of patients who received articulating cobaltchromium prosthesis with cemented stem and polyethylene articulation with the head component (the so-called ‘floating prosthesis’) and found out that all patients rated their outcome as fair (2), good (7) or excellent (3) using the Broberg and Morrey (1986) elbow functional scoring system (Table 2). They concluded that this implant can overcome the complications of silicone-rubber implants. Furthermore, they found out that there was no radiographic evidence of lucency surrounding the cemented stems. Their report also suggested indications for immediate insertion of this implant were Mason type III fractures with ligamentous instability or associated destabilizing fractures such as coronoid process fractures. Kupersmith et al. (2001) suggested that the choice of implant to be used may depend on the mechanism of injury of the radial head. He mentioned that for EssexLopresti injury, where the instability is mainly in the longitudinal and axial direction, a metallic implant should be used to counteract the resultant supra-physiologic loads on the proximal radius. If the injury has been caused by a valgus stress, silastic implant insertion (which is easier) can be carried out along with the more important reconstruction of the MCL. If the MCL reconstruction cannot be done, then a metallic implant is a better choice as it resists excessive valgus force on the elbow better while allowing the MCL to heal.

Table 2 : Modified Functional Scoring System by Broberg and Morrey (1986) (JBJS-78B 1996 : p 248)

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Range of movements (): Flexion contracture Flexion Supination Grade

Pain

Strength (%)

Pronation

Stability

Excellent

-

Normal

Full

Normal

Good

Mild

80 - 100

<20

Normal

>90 >45 >50 Fair

Moderate

80

20

Normal or

90

slight

45

instability

50 Poor

Disabling

<80

>20

Unstable

<90 <45 <50

Surgical timing for radial head excision is another debated issue. Knight et al. (1993) suggested that early radial head excision for unstable fractures should be protected by means of spacer insertion, the most suitable being the metal radial head. This allows soft tissue healing and earlier mobilization. Morrey (1995) stated that type III fractures are best treated with complete excision within 48 hours after injury; the reason being late excision in type III injuries has been less successful in outcome as compared to that for

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the persistently symptomatic elbow after a type II injury. He recommended that delayed excision can be carried out for persistent residual symptomatic elbow after ORIF. Delayed excision can also follow failed conservative management of radial head fractures with 76% reduction of pain and 81% of improvement in strength. CONCLUSION Radial head fractures should be treated accordingly to ensure a good functional outcome. Reconstruction (if possible) should be performed in order to restore the articular surface and to enable satisfactory range of motion of the elbow post-operatively. The important supporting ligaments (especially the MCL) should be managed as well in order to maintain a stable elbow joint. Excision of the radial head with or without arthroplasty is indicated for non-reconstructable fractures of the radial head.

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B : 422-4. 2. Bernstein A.D., Jazwari L.M., Rokito A.S., et al. Elbow joint biomechanics basic science and clinical applications. Orthop. 2000; 23 : 1293-303. 3. Boulas H.J., Morrey B.F.. Biomechanical evaluation of the elbow following radial head fracture - Comparison of open reduction and internal fixation vs. excision, silastic replacement, and non-operative management. Chirurgie de la Main. 1998 ; 17 : 314-20 (Section description). 4. Caputo A.E., Mazzocca A.D., Santoro V.M. The non-articulating portion of the radial head - anatomical and clinical correlations for internal fixation. J. Hand Surg. 1998; 23-A : 1082-90. 5. Diliberti T., Botte M.D., Abrams R.A. Anatomical considerations regarding the posterior interosseous nerve during posterolateral approaches to the proximal part of the radius. J. Bone Joint Surg. 2000; 82-A : 809-13. 6. Esser R.D., Davis S., Taavao T. Fractures of the radial head treated by internal fixation - late results in 26 cases. J. Orthop. Trauma. 1995; 9 : 318-23. 7. Furry K.L., Clinkscales C.M. Comminuted fractures of the radial head arthroplasty versus internal fixation. Clin. Orthop. 1998; 353 : 40-52. 8. Judet T., Garreau D.L., Piriou P., et al. A floating prosthesis for radial head fractures. J. Bone Joint Surg. 1996 ; 78-B : 244-9. 9. Khalfayan E.E., Culp R.W., Alexander A.H. Mason type II radial head fractures - operative versus non-operative treatment. J. Orthop. Trauma. 1992; 6 : 283-9. 10. King G.J., Evans D.C., Kellam J.F. Open reduction and internal fixation of

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radial head fractures. J. Orthop. Trauma. 1991; 5 : 21-8. 11. Knight D.J., Rymaszewski L.A., Amis A.A. Primary replacement of the fractured radial head with a metal prosthesis. J. Bone Joint Surg.1993; 75-B : 5726. 12. Kupersmith L.M., Hausman M.R. Fracture-dislocations of the elbow. Curr. Opin. Orthop. 2001; 12 : 356-63. 13. Moro J.K., Werier J., MacDermid J.C., et al. Arthroplasty with a metal radial head for unreconstructible fractures of the radial head. J. Bone Joint Surg. 2001; 83-A : 1201-11. 14. Morrey B.F. Instructional Course Lectures, The American Academy of Orthopaedic Surgeons - current concepts in the treatment of fractures of the radial head, the olecranon and the coronoid. J. Bone Joint Surg. 1995; 77-A : 316-27. 15. Morrey B.F., Tanaka S., An K.N. Valgus stability of the elbow - A definition of primary and secondary constraints. Clin. Orthop. Rel. Research. 1991; 265 : 18795. 16. O’Driscoll S.W. The unstable elbow. J. Bone Joint Surg. 2000 ; 82-A : 724-38. 17. Ring D., Jupiter J.B. Nonunion following ORIF of radial head fractures. J. Orthop. Trauma. 2000; 14 : 119-20. 18. Shepard J. Effects of radial head excision and distal radial shortening on loadsharing in cadaver forearms. J. Bone Joint Surg. 2001; 83-A : 92-100. 19. Smith G.R., Hotchkiss R.N. Radial head and neck fractures - anatomic guidelines for proper placement of internal fixation. J. Shoulder Elbow Surg.

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1996; 5 : 113-7. 20. Wallenbock E., Potsch F. Resection of the radial head - an alternative to use of a prosthesis? J. Trauma. 1997; 43: 959-61. 21. Witt JD., Kamineni S. The posterior interosseous nerve and the poster lateral approach to the proximal radius. J. Bone Joint Surg. 1998; 80-B : 240-2.