CHENNAI SEPTEMBER 2012

Transcription

1 1 A PROSPECTIVE STUDY OF FUNCTIONAL, CLINICAL, AND RADIOLOGICAL OUTCOME OF FRACTURE SHAFT OF HUMERUS MIDDLE & DISTAL ONE THIRD TREATED BY MIPPO TECHNIQUE Dissertation submitted to UNIVERSITY OF SEYCHELLES AMERICAN INSTITUTE OF MEDICINE USAIM S M.Ch. (ORTHOPAEDIC SURGERY) V.S.HOSPITAL AND RESEARCH CENTRE CHENNAI SEPTEMBER 2012

2 INTRODUCTION 2 Fractures of the humeral shaft account for roughly 3% to 5% of all fractures; generally they are the results of direct trauma. The treatment of these fractures has always been a much debated topic, as both the conservative and the surgical treatment offer advantages and disadvantages. In fact some humeral fractures can be successively managed conservatively. Good and excellent results have been reported because malunions with anterior angle of less than 20 deg or a varus of less than 30 deg are usually well tolerated both functionally and esthetically. Most can be treated nonoperatively. 1 Charnley stated that it is perhaps the easiest of the major long bones to treat by conservative methods. The ranges of motion afforded by the shoulder and elbow joints, with a tolerance for small amounts of shortening, allow radiographic imperfections that cause minimal functional deficit and are well tolerated by the patient. Historically, methods of conservative treatment have included skeletal traction, abduction casting and splinting, Velpeau dressing, and hanging arm cast, each with its own advantages and disadvantages. Functional cast bracing has essentially replaced all other conservative methods and has become the gold standard for non operative

3 treatment because of its ease of application, adjustability, allowance of shoulder and elbow motion, relatively low cost, and reproducible results. 2 3 The goal of operative treatment of shaft of humerus fractures is to reestablish length, alignment, and rotation with stable fixation that allows early motion and ideally early weight bearing on the fractured extremity. Various methods of treating middle and distal humeral shaft fractures have continued to evolve from closed methods, external fixation, antegrade and retrograde intramedullary nailing, and conventional plating to minimally invasive osteosynthesis. External fixation generally is reserved for high-energy gunshot wounds, fractures with severe softtissue injuries, and fractures with massive contamination. Plate osteosynthesis remains the gold standard of fixation for humeral shaft fractures. Plating can be used for fractures with proximal and distal extension and for open fractures. 3 The internal fixation of fractures has evolved in recent years with a change of emphasis from mechanical to biological priorities. One such biological internal fixation is MIPPO (Minimally Invasive Percutaneous Plate Osteosynthesis). MIPPO has been widely used to treat long bone shaft fractures in recent years because of its technical advantages and satisfactory clinical outcomes. The plate is inserted through a

4 4 percutaneous approach with separate proximal and distal incisions. This method causes less soft tissue disruption and preserves the fracture hematoma & blood supply to the bone fragments. 4 In general; there are four conventional surgical approaches to the humeral shaft: posterior, anterolateral, anterior, and anteromedial. Open plate fixation has generally used only the anterolateral and posterior approaches. The anterolateral approach is suitable for proximal and middle third fractures, whereas distal third fractures are best treated using the posterior approach. The anteromedial approach is less useful because of intervening neurovascular structures. The anterior approach is a safe and feasible method to use minimally invasive percutaneous plate osteosynthesis (MIPPO) in the treatment of humeral shaft fractures proven by Dr. T. Apivatthakakul et al. However, the anterior approach might only be suitable for proximal and middle third fractures. 4 we undertook a study to determine the safety of MIPPO technique and also to evaluate the clinical, radiological, and functional outcomes in the treatment of humeral shaft fractures (middle & distal third).

5 AIM OF STUDY 5 The aim of the cadaveric study was to observe the anatomical relationship between the radial nerve and plate during supination and pronation of forearm, so as to determine which position of forearm was the safest for radial nerve in distal humerus. The aim of the clinical study was to determine the safety of MIPPO technique and also to evaluate the clinical, radiological, and functional outcomes in the treatment of humeral shaft fractures (middle & distal one third).

6 SURGICAL ANATOMY 6 The humerus: The humerus is the largest bone in the upper limb. It articulates with the scapula at shoulder joint and the radius and ulna at the elbow joint. The ball shaped head of the humerus articulates with the glenoid cavity of the scapula. The body of the humerus has two prominent features, the deltoid tuberosity laterally for attachment of the deltoid muscle, and the oblique radial groove posteriorly, where the radial nerve and the profunda brachii artery lie as they pass around the humerus. It is generally accepted that a shaft of humerus fracture is one in which the main fracture line is distal to the surgical neck of the proximal humerus and proximal to the supracondylar ridge distally. 5 proximally the humerus is roughly cylindrical in cross section, tapering to a triangular shape distally. The medullary canal of the humerus tapers to an end above the supracondylar expansion. The humerus is well enveloped in muscle and soft tissue, hence its good prognosis for healing in the majority of uncomplicated fractures. There are two muscle compartments in the upper arm: the flexor and the extensor. The anterior flexor compartment consists of three muscles, which are the coracobrachialis, the biceps brachii, and the brachialis. The posterior extensor compartment contains

7 7 one muscle, the triceps brachii. In the distal two thirds of the arm, the muscle compartments are separated by lateral and medial intermuscular septa. 3 Blood Supply: The blood supply of the upper arm arises from the brachial artery, which is the continuation of the axillary artery. The brachial artery begins at the inferior border of the teres major and ends at the cubital fossa opposite to the neck of the radius. At the bicipital aponeurosis, the brachial artery divides into the radial and ulnar arteries. The brachial artery is superficial and palpable throughout its course. It lies anterior to the triceps and brachialis muscles. It first passes medial to the humerus and then anterior to it. When it passes inferolaterally, the brachial artery accompanies the median nerve, which crosses anterior to the artery. There are many unnamed muscular branches and humeral nutrient arteries, which arise from the lateral aspect. The named arterial branches arising from the medial aspect are the deep artery of the arm and the superior and inferior ulnar collateral arteries. The collateral arteries help to form the arterial anastomoses of the elbow region. The nutrient humeral artery enters the humerus on the anteromedial surface and runs distally in the canal towards the elbow. The brachial artery can be easily damaged when

8 8 a fracture occurs. There are two sets of veins, superficial and deep. The two main superficial veins are the cephalic and basilic. The cephalic vein empties at the termination of the axillary vein. The basilic vein merges with the brachial vein to form the axillary vein. The deep veins (brachial veins) begin at the elbow by the union of the radial and ulnar veins and merge with the basilic vein. 6 Nerve Supply: There are four nerves in the arm; The musculocutaneous nerve in the anterior (flexor) compartment, the radial nerve supplies the muscles in the posterior (extensor) compartment. The radial nerve, which is a continuation of the brachial plexus, enters the arm posteriorly to the brachial artery, medial to the humerus and anterior to the long head of the triceps. It then passes inferolaterally with the deep brachial artery and passes around the humeral body in the radial groove. Before it enters the groove, it branches off to the lateral and long heads of the triceps. The branch to the medial head arises within the radial groove. The median nerve has no branches in the axilla and the arm. Likewise, the ulnar nerve has no branches in the arm. The ulnar nerve where it passes superficially posterior to the medial epicondyle is vulnerable to injury. 7, 8

9 HUMERAL SHAFT FRACTURES 1 GENERAL CONSIDERATIONS A fracture of the humeral shaft is a common event, and representing between 3% to 5% of all fractures. Most of fractures will heal with conservative treatment, although a small but majority will require surgery for better functional outcome. Given the extensive range of motion of the shoulder and elbow, and the minimal effect from minor degrees of shortening, a wide range of radiographic malunion can be accepted with little functional deficit. 3 EPIDEMIOLOGY A review by Tytherleigh-Strong et al 9 provided an excellent picture of the epidemiology of shaft of humerus fractures. They found that there was a bimodal distribution of fractures, with a peak, in young, primarily male patients in between 21 to 30 years old and a larger peak primarily in older females 60 to 80 years of age. They point out that high energy trauma was responsible for the majority of injuries in young patients, and that this is the population that most of the orthopedic literature focuses on. The fractures caused primarily by simple falls in

10 older women thus represent a population intrinsically different from that described in reports on surgical intervention for these fractures. 3 2 DIAGNOSIS History As with most fractures, a careful and detailed history and physical examination provide necessary information that serves as a starting point for treatment. The predominant causes of humeral shaft fractures include simple falls or rotational injuries in the older population and higherenergy mechanisms in the younger patient including motor vehicle accidents, assaults, falls from a height, and throwing injuries. A history of minimal trauma causing fracture in the older patient may be the first point to alert the surgeon that the fracture may involve pathological bone (may be it from metastatic disease or severe osteoporosis). 3 The mechanism of injury should match the fracture type: while exceptions do occur, the presence of a spiral fracture indicates a rotational force (such as that which occurs when the arm is forcibly wrenched behind the back). Discordance between history and fracture type is a hallmark of domestic abuse, and again this may represent an opportunity to intervene in a potentially lethal situation. 3

11 Physical Examination 3 In general, the treatment of fracture shaft of humerus is a relatively low priority in the resuscitation of a severely injured patient, which should proceed according to the guidelines of the Advanced Trauma Life Support (ATLS) protocol. Following stabilization of the patient, attention is focused to the affected arm. There is an increased incidence of open wounds, ipsilateral fractures, compartment syndromes and neurovascular injuries in polytraumatized patients, and a careful assessment needs to be performed. There is higher incidence of forearm compartment syndrome in patients, especially children, who have ipsilateral humeral and forearm fractures, the so-called floating elbow. Associated injuries (arterial ruptures, scapulothoracic dislocations, hemo/pneumothoraceses) may be life threatening. The presence or absence of a (usually radial) nerve injury is particularly important to document prior to any intervention. A careful search for open wounds is very important, as the presence of an open fracture accelerates the urgency of the situation. Examination of the shoulder and elbow joint is mandatory: associated injuries or preexisting joint pathology may be an indication for operative management as stiffness may transfer the stress to the fracture site and increase healing time. This will have implications for treatment and counseling of the patient with regards to prognosis. 3

12 Imaging 4 Standard imaging for humeral shaft fracture includes two radiographs at 90 degrees to each other that include the shoulder and elbow joints in each view. For the typical humeral shaft fracture, it is rarely necessary to obtain further imaging. Exceptions to this would include shaft fractures with associated vascular injuries that should be investigated further with an angiogram or computed tomographic (CT) scans of associated intra-articular injuries proximally or distally. CT scanning may also be indicated in the rare situation where a significant rotational abnormality exists: rotational alignment is difficult to judge from plain radiographs of a diaphyseal long bone fracture and a CT scan through the humeral condyles distally and the humeral head proximally can provide exact rotational alignment, especially when compared to the normal side. Given the broad rotational range of the shoulder, fairly large degrees of rotational malalignment can be accepted. However, severe degrees of rotational deformity (>30 degrees) should be avoided as they have a deleterious effect on the functional outcome of the upper extremity. 3 In developing countries ultrasound may provide an attractive alternative to the expense, maintenance, safety issues and space required

13 for conventional radiography. The diagnostic accuracy of ultrasound for long bone fractures is excellent. 3 5 RADIAL NERVE INJURY A radial nerve injury may occur in association with humeral shaft fractures in upto 18% of cases. Most commonly this occurs with middle one third humeral shaft fractures. The Holstein-Lewis fracture, an oblique fracture in the distal one third, for its association with radial nerve injury. Management of the radial nerve injury is controversial. Most injuries are neurapraxias or axonotmesis, and 90% will recover with in 3 to 4 months. The problem is in diagnosing the remaining 10% that will not recover and deciding when surgical exploration is indicated. 10 3, 11, 12, 13 SURGICAL APPROACHES Although numerous surgical approaches to the shaft of humerus have been described, there are two standard techniques, are used most commonly clinically: the posterior approach and the antero-lateral approach. Other described approaches that are useful in specific situations are the direct lateral approach and the direct medial approach.

14 Anterolateral Approach 6 This approach is the preferred option for the majority of middle and proximal one third humeral shaft fractures that require plate fixation. The patient is positioned in the supine or semi sitting position, a pad is placed behind the scapula to elevate the limb and the arm is draped free to include access to the shoulder and elbow if necessary. The limb can be supported on an adjustable covered Mayo stand or an arm board. The skin incision is centered over the fracture site and is performed longitudinally along the palpable lateral border of the biceps brachii. The proximal landmark for extension of the skin incision is the coracoid process, and distally it is anterior to the lateral supracondylar ridge. Next, the subcutaneous tissue and fascia are divided. Proximally, if necessary, dissection is performed between the pectoralis major muscle medially and the deltoid laterally taking care to identify and protect the cephalic vein. If required, part of the broad deltoid insertion can be reflected posteriorly to gain access to the anterolateral shaft. In the middle shaft, the dissection plane is between the biceps and triceps, exposing the brachialis underneath which is split longitudinally along its lateral portion. This muscle has dual innervation (radial nerve laterally, musculocutaneous nerve medially) and correctly performed, this split is roughly in an internervous plane. Distally, dissection continues along the anterior

15 7 aspect of the lateral supracondylar ridge between the brachialis medially and brachioradialis laterally. It is at this point that the radial nerve, as it wraps around the lateral aspect of the distal humerus, is closest to the dissection, and should be identified and protected. It is in danger of being trapped underneath the distal, lateral corner of the plate: this corner should be checked to be free of any soft tissue prior to closing. The elbow range of motion should be examined to ensure there is no impingement from a very distal plate. The advantages of this approach include the favorable position of the patient (for polytrauma cases), the ability to extend the incision proximally to deal with associated shoulder pathology or a proximal extension of the fracture, and identification of the radial nerve distally. Disadvantages include technical difficulty in applying a plate distally along the (thin) lateral supracondylar ridge, the lack of access to any distal medial column pathology, and the noticeable scar that results. Posterior Approach The posterior approach is ideal for fractures that involve the distal third of the humerus, especially those that have an intra-articular extension, or those that require an exploration and repair of an associated radial nerve injury. The patient is typically positioned prone or in the

16 8 lateral decubitus position with the affected side up. The arm is draped free over a bolster and depending on the proximal extent of the dissection anticipated; a sterile tourniquet can be applied. A direct posterior skin incision is centered over the fracture site: it can extend from the tip of the olecranon distally to the posterolateral corner of the acromion proximally as required. After dissection of the subcutaneous tissue and superficial fascia, the triceps is sharply divided distally, taking care to identify and protect the radial nerve (and profunda brachi artery which runs with it) proximally. The radial nerve crosses the posterior aspect of the humerus in the spiral groove roughly equidistant between the tip of the olecranon and the edge of the acromion, and can be identified at the lateral edge of the attachment of the medial head of the triceps. Proximally, it is usually possible to identify an interval between the long and lateral heads of the triceps. The limit of proximal dissection is the overhanging cowl of the deltoid muscle posteriorly and the associated axillary nerve and posterior humeral circumflex artery. Distally, if fixation is anticipated on the medial column of the humerus, the ulnar nerve should be identified and protected. If required, the triceps can be split from the olecranon to gain access to the elbow joint. It should be firmly reattached through drill holes in the bone to prevent postoperative detachment. The advantages of the posterior approach are mainly the ability to access both lateral and

17 9 medial columns distally, the ease of fixing a shaft fracture with a distal extension, the flat posterior surface distally which is ideal for plate fixation, and the exposure of the radial nerve. Paradoxically, its main disadvantage is the proximity (and danger of injury to) the radial nerve. Lateral Approach The extended lateral approach, elucidated by Mills et al, consists of a lateral approach to the elbow that is extended proximally along the humeral shaft. It provides excellent exposure of the distal two thirds of the humerus and the radial nerve. It can be extended proximally into an anterolateral approach and distally along Kocher's interval to deal with lateral elbow pathology, and has the advantage of being performed in the supine position. The skin incision follows a line from the deltoid insertion to the lateral epicondyle. After an incision through the superficial fascia, the triceps is reflected posteriorly and the brachialis and mobile wad of Henry are reflected anteriorly; muscle splitting is not necessary. The radial nerve is identified proximally as it wraps around the lateral aspect of the humerus; it is protected, as is the posterior antebrachial cutaneous nerve branch. The drawbacks of this approach are that access to the medial column distally is not possible and proximally, posterior access to the humeral shaft is limited by the deltoid muscle. The ideal indication

18 for its use is a distal humeral shaft fracture that requires fixation and exploration of the radial nerve (e.g., a Holstein-Lewis fracture pattern). 10 Anteromedial Approach The anteromedial approach to the humerus provides exposure to the brachial artery and median and ulnar nerves. While it is rarely chosen for routine fracture fixation, it is an ideal approach in the rare instance where there is a concomitant brachial artery injury that requires repair. The surgical incision begins distally at the medial epicondyle and extends proximally along the posterior edge of the biceps brachi muscle. After dissection through the subcutaneous tissue and splitting of the superficial fascia, the ulnar nerve is identified and retracted posteromedially. The median nerve and brachial artery are identified and retracted anterolaterally. There are numerous small branches of the artery that require ligation. The medial intermuscular septum is then identified, and can be partially resected to improve exposure and plate application. The triceps is stripped from the shaft and reflected posteriorly as required, and the origin of the coracobrachialis is reflected anteriorly. The main advantages of this approach are the excellent exposure of the neurovascular structures medially (especially if vascular repair is required) and the fact that the scar is well hidden when the arm is against

19 11 the side, which makes it cosmetically appealing. However, neurovascular injury is a major concern, and also proximal extension is very difficult. 3, 11, 12, 13 NONOPERATIVE TREATMENT 3 Nonoperative treatment for fractures of the humeral shaft has a long and well-established history of success, with numerous authors reporting higher rates of union with various types of splints, casts and braces. While anatomic reduction is rarely achieved with nonoperative treatment of these injuries, it is rarely necessary due to the wide range of motion of the shoulder and elbow, such that angulatory, axial, or rotational malunion is easily accommodated and functional limitation is minimal. The humeral shaft is well enveloped in muscle, has a good blood supply, does not bear weight, and is easily splinted, leading Sir John Charnley to state, it is perhaps the easiest of the major long bones to treat by conservative methods. 3 Described techniques include hanging casts, or coaptation splints, sling and swathes, long-arm casts, shoulder spica casts, and olecranon pin traction. However, while good results have been described with most of these methods, functional bracing has become the gold standard for nonoperative treatment due to its ease of application, adjustability, low cost, allowance of shoulder and elbow

20 12 motion, and reproducible record of success. Functional cast bracing was first described by Sarmiento et al in 1977, and consisted of a custommade, circumferential orthosis that allowed elbow and shoulder motion. 14 Indications: 2, 3 1) Humeral shaft fracture which failed non operative treatment where acceptable nonoperative treatment requires maintenance of fracture reduction with less than 20 degrees of sagittal and 30 degrees of coronal angulation and less than 5 cm of shortening. 2) Open fracture of shaft of humerus. 3) Humeral shaft fracture associated with a vascular injury. 4) Humeral fracture in a polytrauma patient. 5) Humeral shaft fracture associated with a floating elbow. 6) Bilateral humeral shaft fractures. 7) Segmental humeral shaft fracture. 8) Humeral shaft fracture associated with an ipsilateral brachial plexus injury.

21 9) Humeral shaft fracture associated with pelvic or lower extremity injuries necessitating crutch ambulation 13 10) Pathologic humeral shaft fracture. 11) Humeral shaft fracture associated with secondary radial nerve palsy. 12) Nonunion or malunion after a humeral shaft fracture. Contraindications: 1) Acceptable fracture alignment in a closed isolated injury. 2) Gustillo grade III B or III C open fracture with extensive wound contamination. External Fixation External fixation of the humerus is a suboptimal form of fixation with a significant complication rate. It is mainly indicated in extensively contaminated or frankly infected fractures, fractures with poor soft tissues (such as burns), or where rapid stabilization with minimal physiologic perturbation or operative time is required. In general external fixation is cumbersome for the humerus and the complication rate is high. This is especially true for the pin sites, where a thick envelope of muscle and soft

22 14 tissue between the bone and the skin and constant motion of the elbow and shoulder accentuate the risk of delayed union and malunion, resulting in significant rates of pin tract irritation, infection, and pin breakage. 3 Plate Osteosynthesis 3 Plate osteosynthesis remains the gold standard for the fixation of humeral shaft fractures against which other methods must be compared. It is associated with a high union rate, low complication rate, and a rapid return to function. It can be used for fractures with both proximal and distal extension, is safe and effective in open fractures, has essentially no elbow or shoulder morbidity, and is stable enough to allow early upper extremity weight-bearing in the multiply injured patient. The surgical approaches, implants, and techniques are familiar to most orthopedic surgeons, and it remains the procedure of choice for humeral shaft fractures that require operative fixation. The union rate following open reduction and internal fixation of humeral shaft fractures averages 96% in a number of large series. Complications are infrequent, and include radial nerve palsy (2% to 5%, usually neuropraxic injuries which recover), infection (1% to 2% for closed fractures, 2% to 5% for open fractures) and refracture (1%).

23 15 A long narrow or broad 4.5mm dynamic compression or limited contact compression (LCC) plate helps to prevent longitudinal fracture or fissuring of the humerus because the screw holes in these plates are staggered. In physically small individuals with thin humerus, a narrow 4.5mm plate may be used. Inserted screws can be angled medially and laterally so they exit staggered on the opposite cortex, minimizing longitudinal stress. In the transition zone distally between the shaft and the supracondylar ridges, as the medial and lateral columns diverge, fixation can be achieved with two 3.5-mm compression plates along with each column, avoiding plate impingement in the olecranon fossa. 3 Intramedullary Nailing Locking, large-diameter humeral nails were introduced with the hope that the results from their use would parallel the clinical success seen with similar devices used for femoral and tibial fractures. Previously available intramedullary implants for the humerus such as Rush pins or Enders nails, while effective in many cases with simple fracture patterns, had significant drawbacks such as poor or nonexistent axial or rotational stability. Henley reported a series of 49 patients with humeral shaft fractures treated with Ender nailing and had only one nonunion, and Brumback reported a 94% union rate with Rush pins and Enders nails,

24 16 although there was a significant rate of insertion site morbidity and backing out of the nails. However, especially when used for comminuted or unstable fracture patterns, some form of additional stabilization was required, either internal (cerclage wire at the fracture site) or external (prolonged splinting). The construct that resulted was often not stable enough to allow early motion or upper extremity weight-bearing in the case of the multiply injured patient with concomitant lower extremity injuries. Problems such as insertion site morbidity, iatrogenic fracture comminution (especially in small diameter canals), and nonunion have been reported. 3

25 REVIEW OF LITERATURE 17 Classic intramedullary osteosynthesis do not provide a stable fixation (Wiss et al., 1986), while open reduction and rigid fixation by classic plates (recommended in the 60s-70s) is requiring large incisions with significant periosteal stripping. Potential complications such as infections, consolidation delays and construct damage due to nonunion undergo frequently (Bucholz et al., 1996). At that time, standard operative procedures considered that in epiphyseal-metaphyseal fractures, each fragment either from the articular or metaphyseal area should be subject for anatomical reduction and stabilization. They were obtained superior biomechanical results (absolute stability) but poor long-term biological effects (Baumgaertel et al., 1998). The main disadvantages of the anatomic reduction and rigid fixation by plates lead to the development of the biological plate osteosynthesis concept. By the development of new plates (bridging plates, Limited Contact-Dynamic Compression Plate, Point-Contact fixator, plates with angular stability) and newer surgical techniques (indirect reduction and Minimally Invasive Plate Osteosynthesis), biological plate osteosynthesis is important to preserve bone vascularity, also to improve consolidation, to reduce the infection rate, to avoid bone grafting. MIPO techniques avoid direct

26 exposure of the fracture site and transform the implants in an internal extramedullary splint More flexible fixation should encourage the formation of callus while less precise indirect reduction will reduce operative trauma. This approach called as biological internal fixation involves the use of locked internal fixators which have minimal implant to bone contact, long span bridging and fewer screws for fixation. 16, 17 MIPO special characteristics are represented by: The treatment purpose in minimally invasive plate osteosynthesis consists of anatomic reconstruction of the articular area, axis, rotation and length reestablishment for the Metaphyseal-diaphyseal area, long plate s osteosynthesis with screws fixed only distally and proximally from the fracture, bridging the comminution and with early functional rehabilitation. 2. MIPO have undeniable advantages over classic techniques: fast healing, reduced complication rate, reduced primary or secondary grafting requirements, and reduced operative time.

27 19 3. Good results obtained by minimally invasive plate osteosynthesis are due to a fast healing by vascularization protection and also to an increased resilience to mechanical stress. 4. Fixation with long plates only distally and proximally from the fracture site maintains a certain instability degree that is useful for an accurate and fast healing (relative instability). 5. Minimally invasive plate osteosynthesis is a demanding technique, requiring a cautious intraoperative clinical and fluoroscopic control in order to reestablish limb axis, rotation and length. 15 Apivatthakakul et al verified in an anatomic study, for the safety of minimally invasive plate osteosynthesis (MIPO) for treating middle-distal one third of shaft of humerus fractures and reported satisfactory 18, 19 results. Pospula et al successfully treated 11 comminuted shafts of humerus fractures with this technique. 20 Apivatthakakul T et al 18 studied on ten arms from five fresh cadavers. Two separate incisions were made in each arm, one proximal and one distal, with the forearm in full supination. A 9-holed narrow DCP was inserted using an anterior approach and fixed with 2 screws each on

28 20 the proximal and distal humerus. Then the tunnel was explored to identify the relationship between the radial nerve and the plate. There was no radial nerve compression or entrapment by the plate. The distance measured from the closest part of the plate to the radial nerve was mm (average 3.2 mm). When the forearm was pronated, the radial nerve moved closer to the plate by 0-3 mm. The results of this study showed that it is possible to treat shaft of humerus fractures by the MIPO method using an anterior approach. Zhiquan An et al 21 analyzed thirty-three patients retrospectively and divided into two groups. Group A patients were treated by MIPO and group B by conventional plating. When compared to the conventional plating, MIPO offers advantages of reduced incidence of iatrogenic radial nerve palsies and accelerated fracture union and a similar functional outcome with respect to shoulder and elbow function. Livani et al 22 studied postoperative ultrasonographic measurement of the distance between the radial nerve and the plate using the MIPO technique. The ultrasound findings reveal that the radial nerve is quite close to the implant, especially in the transition between the third and fourth quarters of the shaft of humerus.

29 21 Jiang Chao-lai 23 studied six fresh-frozen cadaveric specimens of upper extremity were used to verify the safety and feasibility of self designed anatomical anterior locking plate for minimally invasive treatment of fracture shaft of humerus middle and distal one third. He suggested anatomical anterior locking plate is theoretically safe for the minimally invasive treatment of middle-distal third humeral shaft fractures. An Zhiquan 1 studied thirteen patients from May 2004 to October 2005 with an average age of 38.1 years (range, 25 to 60 years). The middle and the distal third shaft of humerus fractures were reduced by closed means and fixed with long narrow 4.5mm dynamic compression plates introduced through 2 separate small incisions away from the fracture sites and placed on the anterior surface of the humerus. Fracture healing time and functional assessments were assessed at an average follow-up of 12.5 months (range, 7 to 19 months) for the affected shoulders and elbows using the UCLA and Mayo elbow performance scoring systems, respectively. All the humeral shaft fractures united with a mean healing time of 16.2 weeks (range, 12 to 32 years). There were no nonunion, radial nerve dysfunction, or implant failures. The UCLA scoring system showed excellent results in 7 cases (53.8%) and good results in 6 cases (46.2%). 1

30 22 Sang-Jin Shin et al 24 studied thirty-one patients with the proximal, middle or distal third humeral fractures underwent MIPO. Fracture union was obtained in all patients at an average of 18.4 weeks. According to the UCLA scores, 9 were excellent and 3 were good for the proximal humeral fractures. For the middle and distal third of humerus fractures, UCLA scoring system showed excellent results in 15 cases and good results in 4 cases. The average KSS scores of proximal and shaft fracture were 92.5 and 98.6, respectively. Complications developed in 3 patients: one patient had radial nerve palsy, one had a fracture just distal to the plate, and one had a rotational deformity.

31 CLASSIFICATION 2, 3, A1 Simple fracture, spiral 1. proximal zone 2. middle zone 3. distal zone A2 Simple fracture, oblique (> or = 30 ) 1. proximal zone 2. middle zone 3. distal zone A3 Simple fracture, transverse (< 30 :) 1. proximal zones 2. middle zone 3. distal zone B1 Wedge fracture, spiral wedge 1. proximal zone 2. middle zone 3. distal zone

32 B2 Wedge fracture, bending wedge proximal zones 2. middle zones 3. distal zone B3 Wedge fracture, fragmented wedge 1. proximal zone 2. middle zone 3. distal zone C1 Complex fracture, spiral 1. with two intermediate fragments 2. with three intermediate fragments 3. with more than three intermediate fragments C2 Complex fracture, segmental 1. with one intermediate segmental fragment 2. with one intermediate segmental and additional wedge fragment(s) 3. with two intermediate segmental fragments C3 Complex fracture, irregular 1. with two or three intermediate fragments 2. with limited shattering (< 4 cm) 3. with extensive shattering (> or = 4 cm)

33 25

34 4, 18, 26 CADAVERIC STUDY 26 The study was performed on eight arms from four fresh cadavers. Two separate incisions, one proximal and one distal, were made in each arm with the forearm in full supination. A 10 to 12 holed long narrow DCP was inserted into a tunnel and fixed with 2 screws each on the proximal and distal humerus. Then the tunnel was explored to identify the relationship between the radial nerve and the plate. There was no radial nerve compression or entrapment by the plate. The distance measured from the closest part of the plate and radial nerve was mm (average 3.6 mm) with forearm in full supination. When the forearm was pronated, the radial nerve moved closer to the plate by a distance of 0 3 mm. To reduce the risk of radial nerve injury, the forearm must be kept in full supination during plate insertion, and excessive force should be avoided during retraction of the lateral half of the brachialis muscle together with the radial nerve in the distal incision. Proximal window - deep dissection was made between the lateral border of biceps muscle and medial border of deltoid muscle. Distal window dissection made between the biceps muscle, medial portion of brachialis muscle and musculocutaneous nerve were retracted by the medial retractor. The lateral portion of brachialis muscle

35 served as a cushion for the radial nerve that was retracted by the lateral retractor. 27 The tunneling instrument was beneath the brachialis muscle toward the proximal incision. The intimately blended fibers of the brachialis and deltoid muscles were incised to allow the passage of the tunneling instrument through to the proximal incision. Joining the both proximal and distal windows and dissecting deeply to the plate in order to identify the radial nerve. The relationship between the radial nerve and the plate with the forearm in supination was mm (average 3.6mm) The relationship between the radial nerve and the plate with the forearm in pronation and radial nerve moves close to the plate by 0-3mm.

36 OPERATIVE TECHNIQUE 1, 4 28 The patients were placed supine on the radiolucent table with the injured side in the position of 90-degree abduction and full forearm supination to reduce the risk of radial nerve injury by increasing the distance between the radial nerve and distal portion of plate. The position of surgeon was on the lateral or cephalic side of the affected arm with the C-arm positioned on the contralateral side to the surgeon. The proximal window is 4cm in length and it is made at the interval between the proximal part of biceps brachialis muscle medially and deltoid muscle laterally. Dissection is then carried down to the humerus, where the anterior border of humerus distal to the crest of greater tubercle is identified. The anterior border of humerus of the humeral shaft runs from the greater tubercle proximally and to the coronoid fosse distally. The line is almost straight so that the straight plate can be placed on it without precontouring. Distally, a 4cm incision is made along the lateral border of biceps muscle approximately 1cm proximal to the elbow flexion crease. The lateral quarter of the brachialiis muscle is then split longitudinally to expose the anterior cortex of the distal humerus.

37 29 A sub muscular extraperiosteal tunnel is prepared between the brachialis muscle and the underlying periosteum with a narrow periosteal elevator or cobbs elevator inserted first from proximal incision distally and then from distal incision proximally. Through this tunnel noncontoured long narrow 4.5mm dynamic compression plate (DCP, 10 to 12 holes) or locking compression plate is inserted from proximal incision, passing over the fracture site and down to the distal incision. Special care should be taken to introduce the implant delicately, in the subperiosteal region, from proximal to distal in middle one third of humeral shaft fractures, always with the elbow joint in semi-flexion. Soft tissue handling should be as gentle and atraumatic as possible. Retractors should be very carefully handled to avoid injury to the radial nerve, by stretching or contusion. Retractors of the Hohmann type should be avoided. The implant should be accurately positioned, fixed and set on the anterior surface of the humeral shaft. One assistant should maintain the elbow in nearly 80 flexion and the forearm in supination while keeping traction on the arm to prevent the fragments from shortening. A 2.0 mm K- wire is then inserted both proximally and distally through a screw hole of the plate to temporarily fix the plate. There are usually 2 screw holes exposed with each incision.

38 30 The displacement of the fractures and the length and the position of the plate are then identified under the C-arm. The proximal end of the plate is located on the anterior portion of the humerus distal to the crest of the greater tubercle. The distal end of the plate is positioned on the anterior middle line of the distal fragment just proximal to the coronoid fossa.care is taken to not extend the distal end of the plate to the coronoid fossa; screw placement can be precarious in that location. When the length of the humerus is approximately restored and both the ends of the plate are in the correct positions mentioned above, the proximal and distal portions of the plate are then fixed to the proximal and distal main fragments, respectively. This is accomplished by placing one screw through the incision into the screw hole not occupied by the K- wire. The screws are then inserted in neutral mode and are not tightened temporarily. The K-wires are then removed, the apposition and the alignment of the fragments are then checked again with C-arm, and significant valgus or varus if any, is corrected by manual manipulation. As long as a straight plate has been fixed exactly on the anterior border of the humerus, there will be no significant rotation or angulation.

39 31 Any significant malalignment is compensated for by shoulder range of motion, as in the closed treatment of these fractures. The anatomical alignment is believed to be restored when the skin crease of the arm is normal in appearance and the longitudinal axes of the main fragments and the plate are parallel to each other when visualized with the C-arm. When the anatomical alignment has been achieved, the previously placed screws are then tightened definitively, and further fixation of the plate is accomplished by inserting screws either percutaneously or under direct vision, with atleast 3 screws proximal and distal to the fracture site. The insertion of the screws can be done either through the skin incisions or additional stab incisions. The radial nerve is not exposed during this procedure.

40 POST OPERATIVE PROTOCOL 1, 4 32 Passive mobilisation of shoulder & elbow in the first week Active mobilisation from second week onwards Wound inspection on second day Suture removal on 12 th day Progressive increase in weight lifting Serial x rays in monthly interval to look for the fracture union. After wound dressing Radial nerve function

41 INSTRUMENTS & IMPLANTS 33 The following implants were used: 4.5mm long narrow DCP (10 to 12 holes) Locking Compression Plates 4.5 mm cortical screws Locking screws

42 The following instruments were used during the surgical procedures: 34 Homann s retractor Bone holding forceps Cobbs elevator Periosteal elevator 3.2 drill bits Drill machine 4.5 Screw driver 2 mm K wires C-Arm imaging

43 MATERIALS AND METHODS 35 An anatomical (cadaveric) study was performed to evaluate the feasibility and safety of MIPPO for the fracture shaft of humerus, and to study the relationship between the radial nerve and the plate with the forearm in full pronation and in supination. The study was performed on eight arms from four fresh cadavers that were obtained from 72hrs to 120 hrs after death from the department of Anatomy and Forensic Medicine; after that, we have done a prospective study of twenty cases of fracture shaft of humerus middle and distal one third treated with minimally invasive percutaneous plate osteosynthesis from January 2010 to June Clinical, radiological and functional outcomes were carried out in all cases. INCLUSION CRITERIA Age above 20 years Fracture shaft of humerus (middle & distal third) Closed displaced unstable fractures

44 EXCLUSION CRITERIA 36 Open fractures Neurovascular injury Distal humerus fracture with intra articular extension Fracture of proximal third of humerus Pathological fractures Skeletally immature patients Patients in which time lag between injury and surgical intervention exceeded three weeks

45 Age distribution: 37 Age No. of patients Above above 60

46 Sex Distribution: 38 Sex Frequency Percent Valid Female Male Total GENDER DISTRIBUTION 5 Female Male 15

47 Side of Injury: 39 Side Frequency Percent Left Right Total SIDE OF INJURY Left Right

48 Mode of Injury: 40 Mode of injury Frequency Percent Fall RTA Total MODE OF INJURY Fall RTA

49 AO/OTA Classification System: 41 AO Classification Frequency Percent A A B Total

50 Associated injuries: 42 Associated injuries Frequency Percentage Distal radius fracture Distal radius fracture right Fracture both bone forearm Fracture both bone right leg mid 1/ None Subtrochateric fracture right with both bone fracture left Total ASSOCIATED INJURIES Distal radius fracture Distal radius fracture right Fracture both bone forearm Fracture both bone right leg mid 1/3 None Subtrochateric fracture right with both bone fracture left

51 Number of patients 43 Time interval 1-5 days days days days 6-10 days days 1-5 days 6-10 days days

52 MAYO ELBOW PERFORMANCE SCORE Elbow Function Pain (max., 45 points) None (45 points) Mild (30 points) Moderate (15 points) Severe (0 points) Range of motion (max., 20 points) Arc > 100 degrees (20 points) Arc 50 to 100 degrees (15 points) Arc < 50 degrees (5 points) Stability (max., 10 points) Stable (10 points) Moderately unstable (5 points) Grossly unstable (0 points) Function (max., 25 points) Able to comb hair (5 points)

53 Able to feed oneself (5 points) 45 Able to perform personal hygiene tasks (5 points) Able to on shirt (5 points) Able to put on shoes (5 points) Mean total (max., 100 points) Excellent - > 90 points Good Fair Poor - 75 to 89 points - 60 to 74 points - < 59 points UCLA SHOULDER RATING SCALE 28 Section 1 - Pain Present always and unbearable; strong medication frequently Present always but bearable' strong medication occasionally None or little at rest' present during light activities; salicylates used frequently Present during heavy or particular activities only; salicylates used occasionally Occasional and slight None.

54 Section 2 Function 46 Unable to use limb Only light activities possible Able to do light housework or most activities of daily living Most housework, shopping, and driving possible; able to do hair and to dress and undress, including fastening bra Slight restriction only; able to work above shoulder level Normal activities. Section 3 - Active forward flexion <30 Section 4-Strength of forward flexion (manual muscle testing) Grade 5 (normal) Grade 4 (good) Grade 3 (fair)

55 Grade 2 (poor) 47 Grade 1 (muscle concentration) Grade 0 (nothing) Section5 - Satisfaction of patient Satisfied and better Not satisfied and worse The maximum score is 35 points. Excellent - 34 to 35 points Good Fair Poor - 29 to 33 points - 21 to 28 points - 0 to 20 points

56 CASE 1 48 Name Age /Sex Mode of Injury Side of injury Open / Closed injury AO Classification Associated Injuries Interval between injury & surgery Post-op period Complications Union / malunion / non union Secondary Procedures: : Dhamodharan : 55/ M : RTA : Right : Closed : A-3.2 : Subtrochateric fracture : 11 days : Uneventful : Nil : Union in alignment : Nil Bone grafting Revision UCLA Score 34 MEPS Score 95 Functional outcome : Excellent CASE II

57 Name : Saleem 49 Age /Sex : 21 / M Mode of Injury : Fall Side of injury : Left Open / Closed injury : Closed AO Classification : A-3.2 Associated Injuries : Nil Interval between injury & surgery : 5 days Post-op period : Uneventful Complications : Nil Union / malunion / non union : Union in alignment Secondary Procedures : Bone grafting : Nil Revision Nil UCLA Score 34

58 MEPS Score Functional outcome : Excellent Pre op x ray AP After U slab

59 51 Immed post op AP Lateral view 6 weeks post op AP Lateral view

60 12 weeks post op AP Lateral view 52

61 53 Active shoulder function CASE III

62 54 Name : Meena Age /Sex : 38 / F Mode of Injury : RTA Side of injury : Right Open / Closed injury : Closed AO Classification : A-2.2 Associated Injuries : Nil Interval between injury & surgery : 10 days Post-op period : Uneventful Complications : Transient neuropraxia Union / malunion / non union : Union in misalignment Secondary Procedures : Yes Bone grafting : Nil Revision : nerve exploration

63 UCLA Score MEPS Score 90 Pre op x rays AP Lateral view Immed post op AP Lateral view

64 Radial nerve Exploration 56

65 Radial nerve function recovered 57 CASE IV Name : Sulochana Age /Sex : 54 / F Mode of Injury : Fall Open / Closed injury : Closed Side of injury : Left AO Classification : A-2.2 Associated Injuries : colles fracture Interval between injury & surgery : 9days Post-op period : Uneventful Complications : radian nerve neuropraxia

66 Union / malunion / non union : Union in alignment 58 Secondary Procedures : Bone grafting : Nil Revision UCLA Score 30 MEPS Score 75 Pre op x- rays AP Lateral

67 59 Immed post op AP Lateral view 6 weeks post op AP Lateral view

68 60 12 weeks post op AP Lateral view CASE V Name : Mathan Age /Sex : 34 / M Mode of Injury : RTA Open / Closed injury : Closed

69 Side of injury : Right 61 AO Classification : A-2.2 Associated Injuries : # both bones forearm Interval between injury & surgery : 10 days Post-op period : Uneventful Complications : Non union Union / malunion / non union : varus-valgus angulation Secondary Procedures : Bone grafting : Yes Revision UCLA Score 26 MEPS Score 90

70 62 Pre op x-rays AP Lateral view Immed post op AP Lateral view

71 12 weeks post op AP Lateral view 63