Mini External Fixator for Open Unstable Phalanx Fracture. Evaluation of Results

Master's Thesis, 2008

80 Pages




List of Figures

List of Appendices

List of Abbreviations

1. Introduction

2. Hypothesis

3. Objectives

4. Review of literature
4.1 Related works
4.2 Historical Review
4.3 External Fixation component Mechanics
4.4 Bio-Mechanics of External Fixator:
4.5 Mechanism of Fracture Healing following external fixation
4.6 Pathophysiology of Phalanx fracture
4.7 Fracture of Proximal and Middle phalanges
4.8 Classification of metacarpal and phalangeal bone Fracture
4.9 Principles of management of open fracture of hand
Goal of Treatment:
Initial Evaluation
Evaluation of the fracture on X-ray

5. Patients and Methods


7. Discussion









This is to certify that DR. Md. Rezwanul Bari has completed a thesis Titled “Evaluation of results of Mini External Fixator for open unstable phalanx fracture” as a partial fulfillment of the requirements for the degree of Master of Surgery in Orthopaedics under my guidance.

Professor DR. Ramdew Ram Kairy

MBBS, MS (Ortho.)


National Institute of Traumatology &

Orthopaedic Rehabilitation (NITOR)

Dhaka Bangladesh


Date of Approval



First of all I am highly obliged and grateful to the Almighty who created me and gives me knowledge to complete this thesis.

I am obliged to my teacher Professor Dr. Md. Siraj-ul-Islam MBBS, MS (Ortho.), Professor cum director, National Institute of Traumatology and Orthopaedic Rehabilitation (NITOR) Dhaka, for his valuable suggestions, teaching and encouragement to carry out his study on this subject at NITOR.

This is my humble pleasure to acknowledge Professor Dr. Ramdew Ram Kairy MBBS, MS (Ortho.), National Institute of Traumatology and Orthopaedic rehabilitation (NITOR), for his active inspiration, constant Supervision, valuable suggestion and guidance in conduction and preparing this thesis.

I express my sincere obligation and gratefulness to my teacher Professor Searjuddin Ahmmed, Professor cum Chairman of Orthopaedic Surgery Department, BSMMU for his valuable suggestions, teaching guidance and encouragement.

I am highly obliged to my respected teacher Professor Khan. A.A. Rizvi MBBS, MS (Ortho.) for his guidance, teaching and encouragement.

I express my gratefulness to my respected teacher Professor Md. Mozammel Hoque for his valuable suggestions and good guidance.

I express my sincere obligation and gratefulness to my teacher Dr. Nukul

Kumar Datta, Associate Professor of Orthopaedic Surgery, BSMMU for his valuable suggestions, teaching guidance and encouragement.

I am also highly obliged to my respected teacher Associate Professor Dr. Abul Kalam (FCPS-Surgery), Professor Dr. Sajjad Hossain Ms (ortho.), Professor Dr. SK Nurul Alam, D-Ortho, MS(Ortho.), for their valuable suggestions, guidance and encouragement.

I am grateful to Dr. A.S.M Monirul Alam, Assistant Professor of Orthopaedic Surgery (NITOR) for his valuable suggestions.

I express respect and gratitude to Dr. Faruque Quasem, Assistant Professor of Orthopaedic (NITOR), Dhaka who took the task of helping me and preparing the thesis.

I must extend my gratefulness to my beloved other teachers for their active help and co-operation.

I am very grateful to all the residents of NITOR who never missed to inform me of the cases.

I am grateful to my patients for their kind cooperation and allowing me to use their photographs.

Finally I am deeply indebted to my parents, my wife Dr. Rimon Afroz (Luna) for their active supports and encouragement during this work.

Dr. Md. Rezwanul Bari


I Distribution of patient in different groups

II Causes of fracture

III Side of hand affected

IV Fingers affected

V Phalanx affected

VI Type of open fracture

VII Fracture Configurations

VIII Effect of delay of treatment


X Complications

XI Duration of keeping immobilization

XII Fracture healing time

XIII Clinical results

XIV Overall results

List of Figures

Abbildung in dieser Leseprobe nicht enthalten

List of Appendices

Abbildung in dieser Leseprobe nicht enthalten

List of Abbreviations

Abbildung in dieser Leseprobe nicht enthalten

1. Introduction

Pretension, intelligence and erect posture distinguish human from the lower animal. Our hands are instrumental for our survival and welfare. We use them when we work, recreate and communicate (Freeland 2000).

Digital muscle balance, hand function, and performance depend upon skeletal integrity. Consequently, displaced fractures that interrupt his integrity may threaten both survival and lifestyle (Freeland 2000).

Hand injuries-the commonest of all injuries –are important out of all proportion of their apparent severity, because of need for near function (Solomon & Warwick 2001).

The incidence of metacarpal and phalanx fracture peaks between 10 and 40 years, a time when athletic and industrial exposure is the greatest (De Jonge et al 1494).

Hand is regularly exposed to all kinds of injuries and phalanges are very vulnerable to trauma and the most common site of fractures in the hand (Barton 1979).

Some of the common causes of hand injuries are crush/compression injuries, blunt trauma, fall, road traffic accident, machinery injuries, sports related activity and explosion/fire arms injuries (Barton 1984).

Most of the fractures are stable and managed conservatively. A fracture is considered unstable if acceptable reduction can not be maintained, if motion at adjoining joints can not be started without loss of reduction (Jobe MT 2003).

New diagnostic and technical refinements have altered treatment methods in the management of fractures and dislocation of hand and wrist but goals remain the same. these goals are function and restoration of motion, strength, and dexterity (Dobyns & Linscheid 1974).

Open hand fractures pose two problems: the wound and the fracture. Fracture alignment and stability are imperative to support wound cleansing, healing and repair of deep structures such as tendons, arteries and nerves(Duncan et al 1993)

Open hand fracture is much more complex in terms of healing, stabilization and consequently long term functional outcome of hand than that of a close one.

Too often these open fractures are treated as minor injuries and major disability results. (Lipscomb PR 1963)

Hand factures can be complicated by deformity from no treatment, stiffness form over treatment and both deformity and stiffness from poor treatment (Swanson 1970).

In Bangladesh most of the open fractures of phalanges are inadequately managed in emergency orthopaedic department in the form of surgical toileting and immobilization with splint or by improperly placed k-wires. This type of treatment leads to stiffness of the fingers and dystrophy of soft tissue due to long term immobilization of the involved fingers.

On these backgrounds, use of an external fixation system can allow certain advantages (Mccauley & Hasting 1999). These are a follows-

(1)It reduces further damage to delicate soft tissue and bone of traumatized hand (minimum disturbance of bone biology) (2) can be performed by closed or open reduction (3) maintenance of osseous length (4) correction to proper alignment (5) adequate accessibility for wound care and soft tissue care (6) early motion of adjacent joints afforded by substantial device rigidity (7) ease of application due to device and instrumental simplicity. (8) Reduces risk of deep seated infection and nonunion.

In the present study, result of unstable shaft fracture of middle and proximal phalanx of fingers and proximal phalanx of thumb by Mini External Fixation have been studied.

The distal phalangeal fracture is stabilized by fibrous septa radiating from base of the bone and inserting into the skin to form an internal splint (Gustilo 1993).

In the present thesis work, the anatomical consideration, fracture patterns and treatment modalities of open hand bone fracture and rehabilitation of the injured hand have been briefly reviewed. Then the prospective study of treatment of open phalanx fracture in presented.

Rationality of Study

Over 75% of work injuries affect he hands: inadequate treatment results in functional disability of the patient. Open hand fractures require prompt attention of surgeons than that of a close one. Unfortunately, most of the fracture is inadequately managed in emergency orthopaedic department.

Requisites of treatment include early adequate debridement, fixation, loose closure of the wounds, occasionally primary skin grafting, careful attention to prevent unnecessary swelling, secondary debridement of viable tissue as needed and early mobilization.

Various modalities of stabilization are available for these fractures. These are k-wire fixation, internal fixation according to AO Standard and Hoffman device for external fixation.

The Hoffman external fixator is very expensive and not always accessible. So the cheap, indigenous external fixator can be a good method for stabilizing these fractures in a poor country like Bangladesh.

2. Hypothesis

External fixation by mini-external fixator is a good method for the management of open unstable phalanx fracture.

3. Objectives

A. General objectives :

Evaluation of effectiveness of mini-external fixator for open unstable phalanx fracture.

B. Specific Objectives :

1) To determine the effect of mini external fixator on hand function in open unstable facture of phalanx.
2) To determine range of motion of fingers.
3) To determine the time required for fracture healing.

4. Review of literature

4.1 Related works

For the management of most forearm and hand fractures, internal fixation with screws and plates is preferable to the use of external fixator. However the small external fixator is now popular among hand surgeons for lesions such as open fractures involving the distal forearm and hand skeleton as well as for certain wrist fracture.

Technique of external fixation in the hand evolved from a variety of homemade devise to commercially available fixators. Percutaneous K-wires protruding through skin and bonding them with methy1 methacrylate (MMA) or with a longitudinal inter connecting K-wire strut (Diclzson type) has been used. Makeshift external fixation devices were developed as a logical extension of the transverse pinning method. Other authors have used similar home made fixators with cement and rigid plastic tubes (Mccauley & Hasting 1999).

Shehadi (1991) further refined his technique by forming the meth1 methacrylate rods inside clear plastic tubes still open on one side applied over the protruding K-Wires. Bending the wire at right angles before applying the plastic tubes allows the fixator to be positioned out of the way.

Eyres and coworkers used a charley compression clamp attached to transverse 2mm K-wires for treating various combinations of metacarpal fractures. Homemade external fixtors are not re-adjustable.

Jaquet in 1976 developed the Mini external fixator which is applicable to fractures in the hand (Riggs & Cooney 1983). Commercially available Mini external fixators include Anderson, AO/ASIF, and Mini Hoffman devices Cziffra of Hungary developed disposable mini-external fixator that is both versatile and inexpensive (Hochberg & Ardenghy 1994).

Stuchin and Kummer’s laboratory comparison of various methods have showed that commercial systems have clearly superior pin but later rigidity was achieved with certain configuration of reinforced bone cement (Solinas & Affanni 1989).

At present AO Switzerland have 5 different designs of Mini hand fixators (Texhmmar & Colton 1996)

But most of these commercially available external fixator are very expensive and not always accessible at the time of need.

4.2 Historical Review

External Fixation is a method of immobilization that uses percutaneous pins placed in bone and linked with external connectors to maintain the fracture segments in a desired spatial relationship (Pacheco & Saleh 1999).

The origin of external fixation go back to Malgaigne, who, in nineteenth century, developed strapped-on metal points and “Claws” to stabilize displaced fractures (Malgalgne & Connassance 1853). As discussed by Peltier (1939) Hippocrates described a method of external skeletal fixation that served his need for a way to immobilize a fracture of the tibia, while at the same time permitting an associated wound or soft tissue injury to be inspected and treated. Parkhill (1898) of Denver and Lambotte (1907) of Brussels built the first cilinically useful external fixators around the turn of century. Codivilla (1905) and Putti (1918) Combined pins and plasters for leg lengthening. However numerous problems such as pin tract infection, insufficient stability, and misalignment of fracture led to decline in the use of external fixation. External fixation devices quickly became popular with young military surgeons at the outset of the world war II (Hoffmann 1938). in November 1943, the use of this technique was restricted to carefully selected cases, only in special indications and only by surgeons trained and experienced in its application.

Since World War II external fixator have developed in two directions. In the west, most surgeons favor simple, steady, unilateral constructs with Low profiles and easy limb access. Whereas in Eastern Europe ring fixators that are highly adjustable but that often encase the whole extremety prevail (Burney 1984). Illizarov (Illizarov et al. 1972) developed highly complex but versatile, ring fixators which appeared to be well suited to correction of limb length discrepancies, misalignments and segmental transport after corticotomy. The AO instrumentalism has successively included five external fixtors: a small compression and distraction device for use in phalanges and metacarpals; the small external fixator for wrist, hand and foot; the wagner (1972) apparatus for bone lengthening; the fixator with threaded rods popularized by Weber (Weber & Magrerl 1985) and tubular external fixator. Since the introduction of dynamic axial fixator in 1979, a number of unilateral dynamizable fixators have been developed, each designed to permit some degree of micro motion at the fracture or osteotomy site.

4.3 External Fixation component Mechanics

Basic elements of external fixators: External fixator comprises of four basic element. These are as follows-

a) Schanz screw as the principal implant.
b) The adjustable clump.
c) The stainless steel tube or carbon fiber rods as frame fomponent.

External fixator varies greatly in appearance, all fixators frame have a small number of components with similar purposes, namely to anchor the frames in the mail bony fragments, to provide longitudinal support and to connect anchoring the supporting elements. Anchorage of bone is done with the help of pins or wires which are generally made of stainless steel. K-Wires used in hand bone very from 0.7mm to 1.6mm. One-half pins or wires may be plane or threaded. Trans-fixation wires pierce the whole thickness of finger or digit and are supported on both side by longitudinal rods (Hehrens F1989) made of stainless steel which are strongest and stiffest element in the fixator frame. In hand, AO fixator may have V-Y quadrangular and fork shaped configuration connecting bars. Simple pin-rod articulations connect a pin independently to a longitudinal rod; clamps or universal pin-rod joints hold two or more aligend pins and connect them, generally over a Universal joint, to a longitudinal rod (Final et al 1987). Rod-rod articulations allow ambulatory, rotator, possibly length correction in the longitudinal support system.

4.4 Bio-Mechanics of External Fixator:

Cliinical and experimental evidence has shown that with the use of AO tubular components, one or two plane unilateral fixator can be made stiff enough to accommodate most injury condition (Behrens & Johnson 1985).

Small bone external fixator comply to the same rigidity principles as large bone systems, their stiffness depending on the number of pins/ segment pin spacing, pin direction, wire diameter, thread characteristics, wire length, type of pin/ rod fixation and connection bar-configuration. Currently there are numerous commercially available external hand fixators. Unfortunately, the bio-mechanical requirement during various application in hand surgery have not been clearly established, and therefore, the selection of a particular model and a specific configuration is often a matter of personal preference. An “ideal” degree of osseous stability for managing each clinical situation treated with external fixation is ill defined. Any fixation technique should attempt to match the bio-mechanical requirement of the clinical situation with stability of the overall construct. The following characteristics have been shown to increase the stiffness of an applied frame and to determine motion at the fracture site (Behrens & Serial 1986).

(1) Increasing the diameter of the implant (Screw, wire, pin)
(2) Increasing the number of implants.
(3) Increasing implant spread.
(4) Using multi-planer fixation.
(5) Reducing distance between fixator frame and bone.
(6) Pre-drilling all half-pin screw sites whenever possible and irrigation drills and implants on insertion with a cool saline solution to avoid thermal necrosis and associate premature loosening.
(7) Applying redial pre-load techniques to half pins or screw fixation.
(8) Improving fastener frame fixation with improved clamp technology or double stacking.
(9) Reducing fractures with fragment contact improving stability and permitting “off loading” of implants (without use of adjunctive lag screw)
(10) Dynamizing frames when possible to allow for bone end contact, a reduction in frame/ pin, screw, wire, stress and a decrease in the tendency to loosen.

In the vast majority of cases, simple unilateral fixator configuration is sufficient, thus avoiding patient’s discomfort and the functional impairment characteristic of bilateral or circular assemblies.

4.5 Mechanism of Fracture Healing following external fixation

Most fractures which have been stabilized with an external fixator consolidate secondary bone union. In fractures with bone loss, an early bone graft or fragment transport may be necessary to assure bone healing and maintain length.

In the light of contemporary inter-fragmentary strain theories about fracture healing, current external fixators have been designed to allow micro motion at the fracture site to promote callus formation. Stable yet less rigid systems of external fixation maintains alignment and length while allowing and actually encouraging beneficial micro-motion. By incorporating the concept of dynamization to gradually increase loading and micro-motion at the fracture site without hampering reduction, new external fixators have met with encouraging results (Weber & Megerl 1985).


It describes the conversion of an external fixator or any fracture import from a statically locked device to a more load-sharing one to promote micro-motion at the fracture site. It is two types. (a) Controlled cyclic dynamization during early

Phase of fracture healing to promote callus. This would be followed by (b) closure type dynamization which allows the approximation of fractured bone ends, elimination gaps that can be created by initial over distraction and resorption at the fracture site. Closure type avoids the chronic over distraction which has given rise to the misnomer “nonunion machine”. Controlled load sharing helps to harden the fracture callus and accelerate the remodeling. As with a hypertrophic non-union, once the early callus has been established, compression and stability at the fracture site promote maturation of the union.


Many researchers have studies the salutary effects of Micro-strain or micro motion on fracture healing. In 1979, Burney (1984) advocated the concept of flexible external fixation to promote callus formation and enhance fracture healing (Halliwell 1998) and experimentally showed 0.5mm/day, at relatively physiological loads for 1 hour a day. Degree of micro-motion is affected accordingly by the wire diameter, number and tension. There are basically two types of fracture healing –through external periosteal callus and primary bone healing. Fracture callus forms in response to the disruption of the periostium and endostium combined with the interfragmentary stain of motion associated with a bone injury. Callus bridges the fracture fragments and acts as both way-stabilizing structural frame work and the biological substrate that provide the cellular material for union and remodeling. Rigid external fixation is associated with absence of callus and requires the fractures to be supported and protected until the bone achieves sufficient strength to prevent re-fracture or angulations when it is once again subjected to functional stresses.

Progressive force transmission across the healing fracture site appears to stimulate hone formation. After healing of soft tissues, patients are encouraged to partial load bearing and then full load bearing once the patients have progressed to full load bearing, a further increase in force transmission can be achieved through dynamization or gradual build down of the fixator frame. Depending on the complexity of the initial frame, the build-down occurs sequentially.

1) Reducing a complex frame down to a one-tube configuration.
2) Moving the longitudinal tube away from the bone.
3) Sequential loosening of the clamps either to further decreases the stiffness of the frame or to allow for sliding of the clamps along the longitudinal tubes: simple fractures need a high stability with the external frame as all displacements take places at one fracture gap and excessive instability leads to high strain situation at the only plane inhibiting fracture healing. Multi-fragmentary fractures are less susceptible to a certain degree of instability as the displacement is shared between several fracture gaps. However, both fracture types can be treated with an external fixator alone.

4.6 Pathophysiology of Phalanx fracture

Stability of phalange fracture depends on location, fracture orientation, and degree of initial displacement. Distal tuft fractures are usually stable despite comminution. Unicondylar and bicondylar fractures involving the interphalangeal joints are inherently unstable. (Divilbiss JB1999). Displaced fractures involving the diaphysis of proximal and middle phalanges are also unstable secondary to the pull of intrinsic and flexor tendons. Fracture with an intact periosteal sleeve and no initial displacement are usually stable.

4.7 Fracture of Proximal and Middle phalanges

Displacement and angulations in fracture of phalanges are influenced by two factors: the mechanism of injury and muscle acting as deforming forces on the fractured bone. Direct blow is more likely to cause a transverse or comminuted fracture, whereas a twisting injury most often results in an oblique or spiral fracture. Usually characteristic deformities develop in displaced fracture of phalanx. Unstable fracture of proximal phalanx typically presents with volar angulations. Proximal fragment is flexed with bony insertion of interosseous into the base of proximal phalanx; once the stability of the proximal phalanx is lost; there is an accordion like collapse at the fracture site, aggravated by further pull of extensor hood by extrinsic muscle.


Excerpt out of 80 pages


Mini External Fixator for Open Unstable Phalanx Fracture. Evaluation of Results
Master In Orthopaedic Surgery (MS-Ortho)
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ISBN (Book)
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The author of this text is not a native speaker of English. Grammatical errors might occur in this text.
mini, external, fixator, open, unstable, phalanx, fracture, evaluation, results
Quote paper
Dr. Rezwanul Bari (Author), 2008, Mini External Fixator for Open Unstable Phalanx Fracture. Evaluation of Results, Munich, GRIN Verlag,


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