| Abstract|| |
Background : The dynamic hip screw has appeared to be a reliable answer for intertrochanteric fractures. Intertrochanteric fractures are composed of different anatomic patterns that vary in their degree of stability. However insufficient impaction allowed by the implant may have an adverse effect on fracture healing.
Methods : One hundred and four patients were divided in two groups and followed up for one year, mean age was 78.2 years. The ninety patients in group I were fixed with short barrel plate and screws of 75mm or less while fourteen patients in group II were treated with standard barrel plate and screws of 80mm or more.
Results : In patients treated with short barrel DHS four out of 90 fractures in group 1 did not heal while in group 2 one out of fourteen did not heal due to failure of standard barrel plate to accommodate the collapse of the fracture fragments. We observed a healing rate of 100% at 3 months.
Conclusion : The DHS is reliable for intertrochanteric fractures.
However the results of our study support the use of short barrel plates rather than standard barrel plates in Indian population with shorter femoral head and neck length to allow sufficient slide when using dynamic screws of 75 mm or less.
Keywords: Intertrochanteric fractures; Dynamic hip screw.
|How to cite this article:|
Agrawala S, Kohli A, Bhagwat A. Short barrel DHS plates for the treatment of intertrochanteric hip fractures in Indian population. Indian J Orthop 2006;40:235-7
|How to cite this URL:|
Agrawala S, Kohli A, Bhagwat A. Short barrel DHS plates for the treatment of intertrochanteric hip fractures in Indian population. Indian J Orthop [serial online] 2006 [cited 2020 Mar 29];40:235-7. Available from: http://www.ijoonline.com/text.asp?2006/40/4/235/34502
| Introduction|| |
Hip fractures continue to be a major cause of death and disability among the elderly. Aside from considerable risk of morbidity and death, hip fractures cause loss of mobility and can significantly reduce patient's quality of life. Comminuted complex fractures of the trochanteric region of the femur pose a difficult situation to the surgeons in their management.
The implant of choice for the treatment of most intertrochanteric fractures is a sliding hip screw with a side plate (DHS). The DHS is indicated for stable and unstable fractures in which a stable medial buttress can be reconstructed. The DHS provides controlled collapse and compression of the fracture fragments. This results in stable fixation and prevents undue stress concentration on the implant. The DHS plates are available in a wide range of sizes and barrel angles, with standard (38 mm) or short barrels (25 mm) for varied clinical situation.
The DHS lag screw easily glides within the DHS plate barrel for controlled collapse and impaction of fragments,. The 25mm short barrel is indicated for specific clinical situations like;
a) Unusually small femurs.
b) Where long impaction distance is expected.
c) A medial displacement osteotomy.
Potential pitfalls encountered during DHS insertion include superior guide wire placement, guide wire breakage or penetration in the joint, loss of reduction, improper screwbarrel relationship and improper plate application,. The build, physique, habits and genetic make up vary markedly in different ethnic groups, it is possible that anthropometric dimensions described as normal for proximal end femur for Westerners might be quiet different from those encountered in Indians.
The aim of this prospective study was to assess the sliding of the screw in the short barrel plate and consequently impaction for the treatment of intertrochanteric fractures in Indian population to allow uneventful healing and early mobilization as the femoral head neck length is shorter.
| Material and Methods|| |
The retrospective study was done between January 2003 to January 2005. One hundred twenty four patients with AO/ OTA 31A intertrochanteric fractures were included in the study. Of these twenty patients were lost to follow up and five patients died due to medical related illnesses.
Of the available one hundred and four patients, ninety patients (86.5%) were treated with short barrel DHS (Group I) and fourteen patients (13.5%) were treated with standard barrel DHS (Group II). Mean age was 78.2 years with 74 female patients compared to 30 male patients. Of the 104 fractures studied sixty-six (63.5%) were stable fractures (type A-1) and thirty eight (36.5%) fractures were unstable (type A2 & A3). All fractures had been caused by a low energy injury most often a fall at home. We excluded patients with fractures associated with poly trauma, pre-existing femoral deformity, previous surgery on the ipsilateral hip or femur, pathological fracture.
Operative data included specific information on the type of barrel plate used, and length of sliding screw. Informed written consent was obtained from all the patients included in this study. The fracture pattern was classified by AO/OTA classification. Group I included patients with shorter femoral head neck lengths in whom we used screws of 75mm or less with short barrel plate. Group II had patients with anthropometrically larger femoral head neck lengths in whom we used screws of 80mm or more with standard barrel plate.
All procedures were performed with the patient in supine position on a fracture table; all fractures were reduced by external maneuvers on an orthopaedic table under fluoroscopic control. Intraoperative anteroposterior and lateral radiographs of the hip were used to evaluate adequacy of reduction and location of screw within the femoral head. A 1350 dynamic hip screw system was applied in all fractures; in group I hip screw of 75mm or less with 4 hole short barrel plates and group II screws of 80mm or more with standard barrel plates were used. Post operatively patients were mobilized out of bed on the 2nd post operative day and walking with partial weight bearing till complete collapse on X-ray was evident.
All patients were given one dose of preoperative antibiotic (Reflin 2gm), prophylactic intravenous, followed by two doses of intravenous antibiotics post operatively. In addition all patients were treated with low molecular weight heparin (Fragmin 5000 I.U.) given subcutaneously one every 24 hours beginning on the day of surgery till the fifth post operative day for prophylactic anticoagulation unless there was a medical contraindication to such treatment. We also recorded the type of anesthesia, the duration of operation and the total duration of fluoroscopy.
A follow up evaluation was performed at 1½, 3, 6 and 12 months. We recorded the presence or absence of limp, mobility and the level of pain. Radiographs of the affected hips were made at each follow up visit, any change in position of implant and extent of fracture union were noted. Migration of the sliding screw was then compared to the first operative radiographs to determine the impaction of the fracture fragments.
| Results|| |
The ninety patients (86.5%) i.e. Group I who were treated with short barrel DHS and fourteen patients (13.5%) Group II who were treated with standard barrel DHS were comparable with regards to all of the pre fracture variables including age, gender, place of residence, mobility score.
All of the patients sustained fractures during a low energy injury most often a fall at home. Surgery lasted for an average 45 minutes for stable fractures and 75 minutes for unstable fractures. The type of anesthesia (general or regional) was similar in both groups. However, there were no significant differences between the two groups with regards to intra operative details like duration of fluoroscopy, the ease or difficulty of insertion of implants. The patients with stable fractures were allowed immediate partial weight bearing post operatively; this being delayed for unstable fractures.
The follow up was done from 3 to 9 months postoperatively; in no case infection was observed. The stable fractures healed without complication in both groups. Almost all screw sliding occurred within thirty days post-operation.
There were five cases of mechanical failures. Four of them occurred in group I which included one case in which the components dismounted in highly comminuted fractures, 2 in which the screw had penetrated the joint and one case with superior cut through the neck, these failures could be reasoned out due to severe osteoporosis and improper screw placement. Other one occurred in group 2 when the device had lost its sliding action, the reason for this included jamming, insufficient glide being available.
| Discussion|| |
Intertrochanteric fractures occur in elderly people with poor bone quality and most are comminuted and unstable. Since early mobilization is mandatory the methods of fixation chosen must allow immediate weight bearing. Stability and sliding are closely related phenomenon. Dynamic hip screws have improved the treatment of intertrochanteric fractures due to sharing of load between the implant and fracture fragments.
Sliding is crucial for femoral stabilization, can prevent non unions. Immediate weight bearing is an advantage of DHS fixation. Immediate weight bearing was allowed in 70% of our patients in both groups with stable fracture pattern. Weight bearing is possible with DHS because of the sliding, which allows permanent bone contact reducing stress on the implant and favoring bone healing. The DHS although has little effect on mortality helps reduce morbidity by allowing patients to return to the pre fracture status, facilitating nursing care and shortening hospital stay.
Group I patients treated with short barrel plate had no complications with regards to sliding. Group II patients treated with long barrel plate had 7.2 % complications due to loss of fixation related to failure to allow sufficient slide within the plate to accommodate the post operative axial collapse of the fracture fragments. Thus Group II demonstrated complications, which were due to failure of sliding mechanism of the implant.
The anthropometric measurement of femoral head-neck length in Indian population is lesser than the average Western values by as much as 5mm, so a shorter head- neck length implies we use screws with shorter thread lengths in the posterior-inferior quadrant of head. In Indian population with smaller heads and shorter neck lengths we must use screws with shorter lengths and hence short barrel plates to provide compression and to allow sufficient impaction to accommodate the postoperative collapse of the fracture fragments.
Simpson et al recommend that the 25mm short barrel be used with lag screws where the length is 80mm or less. This allows for a 20mm slide. Studies by Nakata et al suggest that 15mm of dynamisation would be sufficient so it would definitely not be recommended to use a screw below 75mm with the 38mm barrel.
We conclude that the sliding screw plate allows controlled collapse of the major fragments increasing stability by allowing the sliding screw to accommodate the complete post fixation axial collapse. The telescopic sliding of the screw enables a compulsory sintering of the fracture without leading to penetration of the femoral head or breakage of implant. It is calculated here to allow sufficient slide when employing this technique it is essential to use a short barrel plate when using dynamic hip screw of 75mm or less.
According to this study majority of patients in Indian population had shorter femoral head neck length i.e. group I (86.5 %), so this study demonstrates that as the Indian femoral head neck length is anthropometrically smaller a sliding screw of 75mm or less with a short barrel plate would be recommended as it would have a greater sliding capacity compared to a long barrel plate.
Thus most important factor affecting the load borne by the fracture fragments was the amount of slide available within the device. For patients with short femoral necks as in Indians a short barreled version of the device should be used as would have a greater available sliding capacity.
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Head Of Orthopaedics & Traumatology, PD Hinduja National Hospital, Veer Savarkar Marg, Mahim, Mumbai – 400016
Source of Support: None, Conflict of Interest: None