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The aim of this prospective matched-pair (age, sex, fracture type, residential status, and walking ability at fracture) study was to analyse the short-term outcome after Gamma nail (GN) and dynamic hip screw (DHS) fixation, focusing especially on functional aspects (Standardised Audit of Hip Fractures in Europe [SAHFE] hip fracture follow-up forms), reoperations, and mortality. Both groups consisted of 134 patients. DHS and GN groups did not differ significantly with respect to location of residence at 4 months or returning to the prefracture dwelling (78% vs. 73%, P=0.224). The change in walking ability at 4 months compared to prefracture situation was better in the DHS group (p=0.042), although there was no difference in the change of use of walking aids. The frequency of reoperations during the first year was somewhat lower in the DHS group (8.2% vs. 12.7%, p=0.318). Mortality was lower in the DHS group both at 4 months (6.0% vs. 13.4%, p=0.061) and 12 months (14.9% vs. 23.9%, p=0.044). Although walking ability was better and mortality lower in the DHS group, both methods are useful in the treatment of trochanteric femoral fractures.
Le but de cette étude prospective est de comparer et d’analyser le devenir à long terme des fractures du col fémoral traitées par clou Gamma (GN) ou par le vis plaque (DHS), notamment en ce qui concerne leurs aspects fonctionnels, les réinterventions et la mortalité. Deux groupes de 134 patients ont été comparés. Il n’y a pas de différence significative entre ces deux groupes à 4 mois en ce qui concerne le retour aux activités pré-opératoires (78% vs. 73%, P=0.224) entre DHS et GN. Néanmoins, la marche à 4 mois est bien meilleure dans le groupe DHS (p=0.042), il n’y a pas de différence en ce qui concerne l’utilisation d’aide à la marche, moins de réinterventions dans le groupe DHS (8,2% vs. 12,7%, p=0.318), de même en ce qui concerne la mortalité (6,0% vs. 13,4%, p=0.061) et à 12 mois (14,9% vs 23,9%, p=0.044). Ces deux méthodes sont utiles dans le traitement des fractures cervico trochantériennes, néanmoins, l’amélioration de la marche et la mortalité sont bien meilleures dans le groupe GHS que dans le groupe clou gamma.
Internal fixation of trochanteric fractures was a significant innovation popularised by Jewett and others in 1941. It allowed early mobilisation of the patient and reduced deformity due to malunion . Fixation by the original single-piece implants, however, often failed due to collapse at the fracture site and nail penetration of the head . For this reason, the sliding nail plate was introduced by Pugh in 1955 .
During recent decades, dynamic hip screw (DHS) fixation has been thoroughly assessed, and randomised comparisons have shown it to be superior to fixed nail plates [2, 7], Enders nails , or the Küntscher nails . The dynamic hip screw has therefore become one of the standard treatments of trochanteric fractures.
About 15 years ago, intramedullary fixation with the Gamma nail, which is based on the idea of the Y-nail proposed by Gerhard Küntscher, was introduced for the treatment of trochanteric fractures . The Gamma nail consists of a dynamic sliding screw, which passes through a short intramedullary nail. The design allows sliding between the two parts to produce impaction, as in the sliding screw. The proposed theoretical advantages of the Gamma nail are reduced blood loss due to the percutaneous technique, minimal tissue damage, and shorter operation time [4, 11, 21, 23]. In addition, the possible mechanical advantage over plate fixation is that the nail is closer to the axis of weight bearing through the femoral head, and leverage is therefore reduced [4, 11, 19, 23, 24].
Several studies comparing the Gamma nail and DHS have shown DHS to be a better method in the treatment of trochanteric fractures [4, 23, 24], and some studies have failed to establish any significant differences between these two methods [9, 19, 25], whereas one study concluded that GN was more effective than the DHS . Most of these studies have focused on fracture healing, but the functional outcome has been given less attention .
The aim of this study was to compare the short-term outcomes after GN and DHS fixation of trochanteric fractures, concentrating especially on the functional aspects.
During the years 1991–1999, all hip fractures treated in Oulu University Hospital were prospectively registered on specific Standardised Audit of Hip Fractures in Europe (SAHFE) hip fracture follow-up forms [16, 22]. Functional parameters, i.e. location of residence, ADL functions (ability to dress and undress), walking ability, and use of walking aids were recorded at fracture (Table 2). Reoperations were recorded on a separate form. Trochanteric fractures were classified according to a modified Jensen classification as two-fragment or multi-fragment fractures [16, 17].
There were a total of 575 trochanteric femoral fractures in 563 patients aged over 49 years. Of these, 372 were treated with GN fixation (mean age 78.6 years, range 51–96; 100 males and 272 females), and 203 were treated with DHS fixation (mean age 79.9 years, range 51–101; 50 males and 153 females). The patients treated with GN fixation were cross-matched with the patients treated with DHS fixation for age, sex, location of residence at fracture, walking ability at fracture, and fracture type. Cross-matching was performed by a statistician, and 134 pairs were found. The cross-matching data are presented in Tables 1 and and22.
Follow-up was continued for 4 months by recording the same functional parameters that were recorded on admission. The changes in residential status and walking ability with respect to the situation at fracture were also considered (worse, same, better) (Table 3). Mortality and reoperation rate were recorded for up to 1 year after the fracture.
All operations were on a traction table under spinal anaesthesia. Low-molecular heparin as thromboembolic prophylaxis and preoperative single-shot antibiotic prophylaxis (1.5-g cefuroxime i.v.) were used in all cases. Dynamic hip screws and Gamma nails were inserted by using the previously presented standard techniques in line with the recommendations of the manufacturers of the Gamma nail (Howmedica Ltd., London, UK) and the DHS implant (Stratec Medical, Oberdorf, Switzerland). For both implants, we tried to get the sliding screw into the lowest third of the neck in A-P projection, into the middle part of the neck in latereral projection, and as close as 5 mm to the subchondral bone, as recommended in earlier studies . The selection between these two methods was done by the surgeon according to his preference. The patients were mobilised after an X-ray examination on the first postoperative day in both groups.
Statistical analysis was performed by a statistician. The material was processed and analysed using the SPSS for Windows 12.0.1 software (SPSS Inc., USA). Chi-square test with Yates correction, Fischer’s exact test, and nonparametric Mann-Whitney-U test were used to evaluate the significance of the differences. A difference was considered to be statistically significant when p<0.05.
DHS and GN groups did not differ significantly with respect to delay from admission to operation (1.2 days vs. 1.3 days, p=0.64) and length of hospital stay (8.8 days vs. 7.1 days, p=0.28).
DHS and GN groups also did not differ significantly with respect to living in their own homes at 4 months (56% vs. 50%, p=0.35, Table 2) or returning to the prefracture dwelling (78% vs. 73%, p=0.224, Table 3).
DHS and GN groups did not differ with respect to walking ability at 4 months (p=0.18, Table 2). However, the change in walking ability at 4 months compared to prefracture situation was significantly better in the DHS group (p=0.042 ), although there was no significant difference in the change of use of walking aids (p=0.09, Table 3). The groups also did not differ in the ability to dress and undress at 4 months (p=0.40).
In the GN group, pain on weight bearing was somewhat more common (p=0.108), as well as consumption of analgetics (p=0.111).
In the DHS group, mortality was lower both at 4 months (6.0% vs. 13.4%, p=0.061) and 12 months (14.9% vs. 23.9%, p=0.044, Table 3).
The frequency of reoperations within 1 year was somewhat lower in the DHS group (11 vs. 17, p=0.318). Twenty five of 28 reoperations occurred within the first 4 months, and the reasons (DHS group/GN group) included: 11 fracture displacements (4/7), six loss of position of the nail (2/4), three infections (2/1), three femoral head collapses (1/2), and two refractures (0/2). The reoperation types were revision of fixation in 14 of the cases, arthroplasty in five, Girdlestone in one, and other procedures in the remaining four. Three reoperations were performed after the first 4 months and included one removal of osteosynthesis in the GN group and one arthroplasty and one revision of fixation in the DHS group. Nonunion was the reason for two reoperations.
The incidence of hip fractures has been predicted to increase because of the ageing of the population [18, 19]. It is thus important to strive to improve treatment and to develop better surgical devices, of which the introduction of the Gamma nail is one example. The new treatment modalities must prove their usefulness and superiority over the old methods, even in terms of functional outcome, which is an aspect lacking from most of the earlier comparisons between Gamma nails and other fixation materials.
Our study was a prospective matched-pair study comparing gamma nail fixation and DHS fixation in trochanteric fractures by focusing on functional recovery, reoperation rate, and mortality. Functional outcome was assessed at 4 months, by which time ADL, walking ability, and household activities have been shown to have reached a constant level [3, 12].
DHS fixation required a slightly but not significantly longer hospital stay than GN fixation. This has been stated in many earlier reports [4, 19, 25]. The average lengths of hospital stay in this study were definitely shorter in both groups than those reported in the meta-analysis of 10 trials on Gamma versus DHS nailing by Parker and Pryor in 1996, where the means ranged from 12 to 39 days for DHS and from 12 to 37 days for Gamma nail . The explanation for this difference is the Finnish system of elderly care; the catchment area of our hospital has an extensive network of health centre hospitals capable of providing rehabilitation at a very early postoperative phase.
The facts that the GN is said to be more rigid and to allow full weight bearing earlier than the DHS even in cases of very complex fractures, and that DHS fixation requires more extensive surgery than GN fixation did not have any marked effects on the functional outcome. On the contrary, walking ability evaluated as the change compared to the preoperative situation was better in the DHS group. Similar results have also been reported by Hoffman and Lynskey , whereas Goldhagen et al. , Sabharwal et al. , and Park et al.  observed no significant differences. The greater impairment of walking ability after GN fixation than after DHS fixation in this study may be at least partly due to the higher rate of complications in the GN group.
The cutting-out from the femoral head is regarded as a typical complication of DHS fixation [4, 10, 19], but in our study such cutting-out occurred more often with gamma nails. Our findings are in agreement with some earlier reports [9, 14, 25], whereas Hoffman and Lynskey , Fornander et al. , and Park et al.  reported roughly similar cutting-out rates for both methods. We agree with Bridle et al.  in that cutting-out from the femoral head is usually due to a technical error rather than implant dysfunction.
Complications specific to GN are fractures around the greater trochanter, fracture displacement by nail insertion, and fractures of the shaft of the femur . Fracture of the femoral shaft at the distal end of the intramedullary part of the implant is considered the most serious complication of GN fixation [4, 19, 23, 24]. Both of the two fractures of the femoral shaft that occurred in our GN group were associated with a fall. The fracture rate of the femoral shaft, which was 1.5% in our study, was similar to those published in earlier reports [11, 20].
Most studies have failed to reveal any difference in postoperative mortality between GN and DHS fixation [10, 14, 19, 24]. Some studies, however, have reported higher mortality after GN fixation [13, 25] and some after DHS fixation [4, 8]. Our findings of higher mortality after GN fixation are in line with the earlier results, and we think that the difference was at least partly due to the higher number of complications requiring reoperations associated with the GN fixation.
It is concluded that both methods are useful in the treatment of trochanteric femoral fractures, although the results were slightly in favour of DHS fixation with respect to walking ability and mortality.
This study was financially supported by the Oulu University Hospital Board. We thank research nurse Eila Haapakoski for help in data collection and Mr. Hannu Vähänikkilä for help with the statistical analysis.