Early Experience with Low Profi le Plate Osteosynthesis for Metacarpal Fractures

Methods: This was a hospital based prospective study. Unstable and irreducible fractures were managed by open reduction and internal fixation with low profile miniplate and were followed up for 6 months. The functional outcome after fracture treatment was assessed by ability to perform acts of daily life and calculating American Society for Surgery of the Hand Total Active Flexion (ASSH TAF) score.


INTRODUCTION
][7][8][9][10] Biomechanical studies have consistently shown that a dorsally applied plate provides the greatest rigidity; therefore this fi xation technique has become the most common method of open reduction and internal fi xation for displaced, unstable metacarpal fractures. 11,12Suffi cient rigidity helps to ensure timely fracture healing and to allow earlier and more intensive digital rehabilitation, which is the mainstay of good functional outcome.
The majority of papers looking at this subject have included both metacarpal and phalangeal fractures and reported higher complication rate. 4,13,14Most of these complications were associated with thick plates and was more pronounced in phalangeal rather than metacarpal fractures.The aim of our study was to evaluate the functional results after closed and extra-articular metacarpal fractures treated by low profi le plates and screws.

METHODS
A prospective hospital based study was conducted at Shree Birendra Hospital, Nepal, for a period of two years (July 2006 to August 2008).Only unstable, irreducible and displaced fractures were enrolled, excluding open fractures, intraarticular fractures, younger patients (less than 14 years), and diabetics.The ethical approval and informed written consent was taken.Total 17 patients with 19 metacarpal fractures (two patients had two metacarpal fractures each) were treated at our institution by open reduction and internal fi xation (ORIF) with miniplate and screws.The characteristics of plate and screws are given in box 1.
All operations were performed with a pneumatic tourniquet bandage in upper arm.A dorsal approach was used and access to the bone was achieved by retracting the extensor tendons ulnarly or radially.The periosteal sleeve was also opened longitudinally and the bone exposed subperiosteally to visualize the fracture.The fracture was then reduced by longitudinal traction on the digit, and the reduction was held in compression by a towel clip.Fixation was achieved with plate and screws according to the standard AO technique with minimum of four cortices in each side of fracture (see fi gure 4 a,b,c).The periosteal sleeve was closed over the plate and wound closed in layers.Postoperatively, elastic bandage was applied and exercises were started after 2-3 days by the patient him/herself following a physiotherapist's instructions.
The patients were followed up at 2 weeks, 4 weeks, 8 weeks, 3 months and fi nally at 6 months for clinical and functional evaluation.The functional outcome after fracture treatment was assessed by ability to perform acts of daily life (writing, drinking, shaking hands, combing, opening cap of a bottle, button own shirt, brushing and washing face) and calculating ASSH TAF (American Society for Surgery of the Hand Total Active Flexion) score at each follow up. 15tients were requested to perform above mentioned acts of daily life (ADL) at the time of follow up.TAF (Total Active Flexion) was calculated by adding the active fl exion at metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints (See fi gure 4 d,e,f,g).Patients with ≤ 120 0 of ASSH TAF score are classifi ed as poor: 121 0 -220 0 as good; and ≥ 221 as excellent.
Radiographs were taken to evaluate bony union at 1 and 3 months and as per requirement if there is delayed union.Data were analyzed using statistical packages for social sciences (SPSS) version 11.5 for windows.Chi-square and t-test were applied for testing statistical signifi cance wherever applicable and the level of signifi cance was set as p<0.05.

RESULTS
Initially we had 17 patients with 19 metacarpal fractures (two patients had double metacarpal fractures) operated.One patient with double (IV th and V th ) Metacarpal fracture (Figure 1), sustained re injury of the same hand and bend his plates.This patient refused to participate further in the study, so for fi nal analysis we had 16 patients with 17 metacarpal fractures.
The mean age of the patient was 31.50±9.02years (range 20-54 years).Fourteen (87.5%) patients out of 16 fell in age group of 20-40 years.Majority of our patients were male (87.5%) with male female ratio of 7:1.The IV th Metacarpal was most commonly involved (47.1%), followed by III rd (29.4%),V th (17.6%) and II nd (5.9%).Oblique fracture was the most commonly observed fracture in 8 (47.1%) patients followed by spiral in 6 (35.3%) and transverse in 3(17.6%).The demographic and clinical data are presented in table 1.
Eight (50%) patients were able to perform ADL at two weeks which increased to 87.5% (14/16) at 1 month follow up.Two patients who had developed Refl ex sympathetic dystrophy (RSD) could perform their complete ADL at 3 months follow up.
The TAF improved in successive follow-up, it was 240.59±36.82 at 3 month and 261.76±24.87 at the end of 6 months.At three months, mean TAF was signifi cantly lower in comparison to the normal ray (p=0.002),although ASSG TAF was excellent (>220 0 ).The mean TAF of operated ray improved to 261.76±24.87 at 6 month, which was not signifi cantly different (p=0.06)from that of normal ray (272.94±4.69).According to ASSH TAF scoring system, 13 (81.25%)patients had excellent, 12.5% Good and 6.25% poor outcome at three months follow-up which improved to 87.5% (14) excellent, 6.25% (1) good and 6.25% (1) poor outcome at the end of 6 months.Three (18.75%) patient developed complications, 12.5% (2) had Refl ex sympathetic dystrophy and 6.25% (1) had hypertrophied surgical scar.We had one case of implant failure, bend implant after re injury, which was excluded from our study, as he refused to participate further.

DISCUSSION
Hand and upper extremity injuries are one of the most common injuries treated in emergency departments. 16ractures of the phalanges and metacarpals account for 10% of all fractures and it account for at least 41% of all fractures of the upper extremity. 17Early techniques of splint immobilization worked well for simple hand fractures, but fell short in more complex injuries.The list of techniques described for treatment of these fracture is exhaustive.Whatever technique is used, principles of fracture management remain the same, with goal to Early Experience with Low Profile Plate Osteosynthesis for Metacarpal Fractures restore full hand function.As a general rule, this can be accomplished through anatomic reduction, obtaining adequate stability to allow early range of motion.The use of percutaneously inserted wires has remained a mainstay of the treatment of hand fracture till date.In the developing world like Nepal, where intraoperative image intensifi er is not readily available to guide wire placement, this procedure is diffi cult to perform. 18late fi xation has advantage of rigid fi xation which allows earlier rehabilitation and return to work, and since open reduction is performed it does not require image intensifi cation.Interest in plate fi xation of hand fractures stems from the biomechanical studies of Fyfe and Mason and Massengill et al. 8,10 Their study showed that plates and screws provided rigid stabilization that would permit early motion, which hopefully would minimize the stiffness and tendon adhesions that result from immobilization. 3,19Biomechanical studies have consistently shown that a dorsally applied plate provides the greatest rigidity in apex dorsal bending (for most fracture types); this fi xation technique has therefore become the most common method of open reduction internal fi xation for displaced, unstable metacarpal fractures. 11,12though our sample size is very small to come to a conclusion regarding demographic results, they are very much similar to many studies published earlier.1][22][23] The male predominance in our series is because this study was performed at military hospital, and in Nepalese army females are very few in numbers.Almost 90% of our patients fell in age group of 20-40 years.Higher incidence in this age group have economic impact which is directly proportional to time of immobilization.Speedy recovery and early return to work becomes doubly important in military population, as they have to undergo many trainings for their future career.Higher incidence in this age group was also reported by Onselen and Stanton. 20,23though fracture of the Vth metacarpal is the commonest at any age group, they have higher tolerance to displacement and angulations, so most of them are managed conservatively.This is the reason why only 18% of this study had fracture of Vth metacarpal.In our study fracture of IVth and IIIrd metacarpals were the commonest, which was similar to Trevisan's series. 21t many authors have evaluated ADL in their studies, which we think is an important parameter of functional outcome.ADL is even more important as majority of metacarpal fractures occurs in the dominant hand.Fourteen (87.5%) patients could perform ADL at 4 weeks, was similar to that of Travesian's series (29.6 days). 21welve (75%) patients were able to do demanding work (at preinjury level) at 8 weeks and 94% were able to do so by 3 months.
In our study 87.5% ( 14) had excellent, 6.25% (1) good and 6.25% (1) poor outcome at the end of 6 months, these results were comparable to similar studies (Table 2).Although the ASSH TAF score was excellent (>220 0 ) from 8 weeks onwards, the mean TAF was signifi cantly lower (p=0.002)till 3 months follow up.But, there was no signifi cant difference in mean TAF of injured and normal ray at 6 months.
We have lower complication rates in comparison to many studies (Table 3).Most of the complications in previous studies were related to thickness of implant and severity of soft tissue injury.Although our study had very small sample size to compare with these studies, lower complication rates may be because of low profi le of the plate and careful handling of the tissue and closure of periosteum over the plate.One another aspect is that, majority of these studies have included phalangeal fractures along with metacarpal.We agree to the fact that plate fi xation for phalangeal fracture causes more tissue damage leading to poor outcome, but plate osteosynthesis for metacarpal fractures has better scope and its excellent outcome should not be undermined by the poor outcome of phalangeal fractures.Two of our patients have developed refl ex sympathetic dystrophy (RSD), which has compromised the TAF and functional outcome.It is diffi cult to explain RSD occurred because of surgery or it would have been there even if managed conservatively.The incidence of RSD followed by hand injury is higher than that we had in this series.
One of our patients had bent his plate when he fell down on the fractured hand 4 weeks after surgery (Figure 1).Only Trevisan has mentioned one case of asymptomatic hardware breakage, other wise no such complication has been mentioned in reviewed literatures. 21Bend plate may be because of its low profi le with low bending rigidity.Protection after surgery in less compliant patients can be considered.

CONCLUSION
Although closed reduction and percutaneous pinning with K-wires holds theoretical advantages over open reduction and internal fi xation, favorable outcomes can be expected by low profi le plate osteosynthesis in lowseverity metacarpal fractures.Box 1. Characteristics of plate and screw

Figure 1 .
Figure 1.Bent implant after re injury a. Preoperative X-Ray.b. immediate postoperative X-Ray c. Bending of plate after re injury.

Figure 2 .
Figure 2. Illustration of case 4 a. fracture of IV th Metacarpal.b.Fixed with low profi le miniplate with four cortices each side.c. fracture united at 3 month followup.d. implant removed after 6 months.e,f,g,h: TAF calculation.

Table 1 .
Early Experience with Low Profile Plate Osteosynthesis for Metacarpal Fractures Demographic and clinical data.

Table 2 .
Comparisons with similar studies