The effect of an attachable lateral support plate on the stability of intertrochanteric fracture fixation with a sliding hip screw

BACKGROUND: Use of a sliding hip screw (SHS) alone for some unstable intertrochanteric femur fractures can allow excessive medial shaft displacement during impaction. This study evaluated the effect of an attachable lateral support plate on these fractures after loading. METHODS: Unstable, three-part intertrochanteric fractures were created in 10 matched pairs of embalmed femurs that were instrumented with 135-degree SHSs with or without an attachable lateral support plate. Under physiologic loading, inferior and lateral head displacements and lag screw sliding distances were measured. RESULTS: After 10,000 cycles at 750 N, all measurements for femurs with the lateral support plate were significantly less than for the femurs with the SHS alone: mean lateral difference was 1.7 mm (34%) (p < 0.05), mean inferior difference was 3.0 mm (38%) (p < 0.05), and mean lag screw sliding difference was 4.5 mm (58%) (p < 0.05). CONCLUSION: The addition of an attachable lateral support plate to an SHS significantly decreased displacement of the femoral head after cyclic loading.     

Intramedullary fixation of unstable intertrochanteric hip fractures: one or two lag screws

OBJECTIVE: To compare the screw sliding characteristics and biomechanical stability of four-part intertrochanteric hip fractures stabilized with an intramedullary nail using either one large-diameter lag screw (intramedullary hip screw [IMHS]; Smith & Nephew, Memphis, TN) or two small-diameter lag screws (trochanteric antegrade nail [TAN]; Smith & Nephew, Memphis, TN). DESIGN: Laboratory investigation using eight matched pairs of cadaveric human femurs with simulated, unstable intertrochanteric hip fractures. INTERVENTION: One femur of each matched pair was stabilized with an IMHS intramedullary nail, and the other was stabilized with a TAN intramedullary nail. Femurs were statically, then cyclically loaded on a servohydraulic materials testing machine. Finally, all specimens were loaded to failure. MAIN OUTCOME MEASURES: Screw sliding and inferior and lateral head displacements were measured for applied static loads from 500N to 1250N. The same measurements were obtained before and after cyclically loading the specimens at 1250N. Ultimate failure strength of the implant constructs also was determined. RESULTS: There was no significant difference between the TAN and IMHS in static or cyclical loading with respect to screw sliding or inferior and lateral head displacements. There was a statistically significant difference (P < 0.02) in failure strength, with the IMHS construct failing at an average of 2162N and the TAN construct failing at an average of 3238N. CONCLUSION: The two constructs showed equivalent rigidity and stability in all parameters assessed in elastic and cyclical tests. The TAN had a greater ultimate failure load.     

A biomechanical analysis of the sliding hip screw: the question of plate angle

There is general agreement that the implant of choice for intertrochanteric fractures is the sliding hip screw (SHS). However, considerable differences of opinion exist as to which plate angle--varying from 130 to 150 degrees--is preferred. Thus far there has been no cadaver-based biomechanical analysis of this problem. To examine these questions, we determined the effect of plate angle on plate strain and proximal medial femoral strain distribution in cadaver femurs fixed with 130, 135, 140, 145, and 150 degrees SHS after experimentally produced stable and unstable intertrochanteric fractures. Twenty-four fresh adult cadaver femurs were assigned randomly to either the 130, 135, 140, 145, or 150 degrees SHS group. Each femur was radiographed and bone mineral density was determined by dual-photon absorptiometry. Multiple-strain gauges were affixed to the femur, with specific focus on the proximal femur and plate. Femurs were loaded at 25 degrees adduction in increments of 70 N from 0 to 1,800 N in a servohydraulic testing machine. Femurs were tested in a progressive manner: (a) intact femur; (b) intact femur with SHS inserted; (c) a stable two-part intertrochanteric fracture reduced with SHS; (d) a four-part fracture with the posteromedial fragment (PMF) reduced anatomically by a lag screw; (e) the same fracture with the PMF rotated 180 degrees and held in place by a lag screw to approximate a "near-anatomic" reduction; and (f) the same fracture with the PMF discarded. Screw sliding measurements were determined at regular intervals throughout each test.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of a modified IMHS for unstable intertrochanteric fractures

The treatment of unstable intertrochanteric fractures in elderly osteopenic patients, especially those who cannot follow limited weight bearing instructions, is controversial. Recent publications indicate concern with excessive sliding of telescoping nail or sliding screw devices when used in these unstable intertrochanteric fractures. In our experience with the use of intramedullary hip screw (IMHS) in these fracture patterns, we have observed excessive sliding and collapse of the fracture in some patients. We modified the keyed centering sleeve by threading its internal distal third and substituted the compression screw with a custom bolt to obtain restricted sliding or rigid fixation depending on the gap between the lag screw and custom bolt. We used this modified system in static configuration to treat five patients who had an unstable intertrochanteric fracture of the femur. The length of the involved limb measured at the time of consolidation showed no shortening. In view of these results, intertrochanteric hip fractures that are unstable in patients with poor bone-stock can be fixed using the modified IMHS in a static or controlled sliding configuration. Received: 4 February 2002/Accepted: 18 March 2002     

Biomechanical analysis of the percutaneous compression plate and sliding hip screw in intracapsular hip fractures: experimental assessment using synthetic and cadaver bones

We compared the mechanical behaviour of osteosynthesis with the percutaneous compression plate (PCCP) compared with the standard osteosynthesis sliding hip screw (SHS) in intracapsular hip fractures. We created 10 stable and 10 unstable intracapsular hip fractures in 20 synthetic femurs. Each fracture was fixed with either the SHS or PCCP. In six pairs of cadaver femurs, we created unstable intracapsular hip fractures and fixed them with the SHS or PCCP, at random on the left or right side. All femoral heads were exposed to a cyclic, combined axial and torque load until failure. In each group, the PCCP resisted a significantly higher load than the SHS. Clinical prospective studies are needed to confirm these in vitro findings that the PCCP is more stable than the SHS.     

Intramedullary hip screw versus sliding hip screw for unstable intertrochanteric femoral fractures in the elderly

We report a randomised, prospective study comparing a standard sliding hip screw and the intramedullary hip screw for the treatment of unstable intertrochanteric fractures in the elderly. One hundred and two patients were randomised on admission to two treatment groups. Fifty-two patients were treated with a compression hip screw (CHS), and fifty had intramedullary fixation with an intramedullary hip screw (IMHS). Patients were followed for 1 year and had a clinical and radiological review at 3, 6 and 12 months. The mean duration of operation and fluoroscopy screening time was significantly greater for insertion of the intramedullary hip screw. There was no difference between the groups with regard to transfusion requirements or time to mobilise after surgery. There were two technical complications in the CHS group and three in the IMHS group. There was no significant difference between the two groups in radiological or functional outcome at 12 months. It remains to be shown whether the theoretical advantages of intramedullary fixation of extracapsular hip fractures bring a significant improvement in eventual outcome.     

Clinical results of unstable intertrochanteric fracture treated by dynamic hip screw with tension band wire reinforcement

Although intertrochanteric fractures of the proximal femur are commonly seen in geriatric patients, their treatments remain challenging for most orthopedic surgeons. Dynamic hip screws (DHSs) with slide plating have become the golden standard for treating these difficult fractures. The goals of lateral wall buttress reconstruction and stable fixation are to promote early ambulation and partial weight bearing, which in turn minimizes possible morbidity. Intertrochanteric fractures, especially those that are unstable, when fixed with DHSs alone will often result in significant medial displacement of the shaft, secondary to excessive sliding of lag screws within the barrel and a higher incidence of lag screw cut-out. Fixation with an additional trochanter stabilizing plate (TSP) superimposed on the regular DHSs has recently gained wide advocacy among authors. However, TSP is expensive. To overcome problems with medial displacement of the shaft, excessive head-neck fragment collapse, and excessive sliding of lag screws within the barrel and lag screw cut-out, and to reduce the cost of TSP as well, we treated 2 patients with unstable intertrochanteric fractures by fixing the fractures with dynamic hip screws reinforced by tension band wiring. Both patients had good results without complications. The final outcomes were comparable to those of fractures fixed with DHSs and supported by TSP, but the cost was markedly lower. Additionally, complications from lateralization of the greater trochanter were significantly prevented. Our method of DHS fixation with tension band wiring reinforcement may be beneficial for patients with unstable osteoporotic intertrochanteric fractures.     

The trochanteric nail versus the sliding hip screw for intertrochanteric hip fractures: a review of 93 cases

BACKGROUND: The trochanteric nail, a redesigned short gamma nail, (Howmedica, Rutherford, NJ) was introduced in the United States during 1998 for the treatment of intertrochanteric fractures. METHODS: We retrospectively reviewed 93 patients who were treated for an intertrochanteric fracture with either a sliding hip screw (SHS) or the short trochanteric nail (TN). RESULTS: In all, 94% of the patients in the sliding hip screw group healed without complication. There was one case of femoral head necrosis, one lag screw cutout, and one hardware removal for pain. Eighty-nine percent of the patients in the trochanteric nail group healed without complication. There was one late fracture at the tip of the nail, three cases of lag screw cutout, and one nonunion. CONCLUSIONS: This study suggests that the trochanteric nail is a reasonable alternative to the sliding hip screw when used for intertrochanteric fractures, although it may be associated with higher complication rates.     

Technical pitfalls in the use of the sliding hip screw for fixation of intertrochanteric hip fractures

Two hundred fifty consecutive intertrochanteric fractures treated with a sliding hip screw (SHS) over a three year period were reviewed and specific types of technical pitfalls identified. Most pitfalls were technique dependent and potentially preventable with proper attention to the principles of fracture reduction and insertion of the device. Pitfalls encountered with the use of the SHS occurred as a result of either poor fracture reduction or implant insertion. Problems related to fracture reduction included poor radiographic visualization, posterior sag, varus angulation, and internal rotation of the femoral shaft in relation to the femoral neck. Potential pitfalls encountered during SHS insertion included superior guide wire placement, guide wire breakage or penetration into the hip joint or pelvis, loss of reduction during lag screw insertion, improper screw-barrel relationship, and improper plate application. Finally, the SHS may not be the implant of choice for all extracapsular hip fractures (i.e., the reverse obliquity fracture). This paper identifies the various pitfalls that may occur with the use of the SHS for the fixation of intertrochanteric hip fractures. Illustrative cases are provided and guidelines for avoiding these surgical pitfalls suggested.     

Sliding hip screw in pelvis: a rare intra-operative complication

We are presenting an unusual intra-operative complication of penetration of sliding hip screw (SHS) into the pelvis during fixation of an intertrochanteric fracture neck of femur in a 78-year-old man along with the technique of retrieving it.     

The Medoff sliding plate and a standard sliding hip screw for unstable intertrochanteric fractures: A mechanical comparison in cadaver femurs

The Medoff sliding plate has a dual side capability along both the femoral shaft and neck to increase theoretically interfragmentary compression and load-sharing in hip fractures. We studied intertrochanteric fracture fixation in cadaveric bone to determine whether this device has a mechanical advantage over a standard sliding hip screw.

2-part and 4-part fractures were created in 12 cadaver femurs. The fractures were fixated and sequentially destabilized; bone and plate strains and fragment displacements were determined during testing, as a function of applied physiological loads before and after short-term cycling.

The Medoff sliding plate imposed a higher mean medial cortex strain than the sliding hip screw in all fracture models and at all loading levels, and the difference was statistically significant in the 2-part and in the unstable 4-part fracture models. The loading of the medial cortex region after cycling was approximately 50% higher in the Medoff samples than in the sliding hip screw samples. There were no significant differences in plate strains, fracture displacements or load to failure between the 2 devices.

These observations favor the dual sliding principle as regards providing fracture compression and load-sharing, which may explain low failure rates in clinical series of unstable intertrochanteric fractures, treated with the Medoff sliding plate.     

Comparison of accuracy of lag screw placement in cephalocondylic nails and sliding hip screw plate fixation for extracapsular fractures of the neck of femur

This study compared the accuracy of lag screw placement between extracapsular femoral fractures fixed with sliding hip screw plate systems and those fixed with cephalocondylic nails. It involved 75 retrospective radiographs of fractures fixed with either a cephalocondylic nail (32) or a sliding hip screw plate system (43). Postoperative anteroposterior and lateral radiographs of the hip were scanned using a digital X-ray scanner and measured using computer software. Measurements were conducted by two independent observers, and the radiographs were calibrated to correct for magnification. Accuracy of lag screw placement was determined by "tip apex distance," described by Baumgaertner et al., and by the ratio method described by Parker. The mean tip apex distance was 24.0 mm in sliding hip screw plate systems and 21.1 mm in cephalocondylic nails. This was found to be statistically significant. Lag screw placement through cephalocondylic nails is more accurate and therefore has less chance of cut-out compared with sliding hip screw plate systems. There was no statistically significant difference using Parker's ratio method because this method quantifies the direction of the screw rather than the depth of penetration.     

Helical blade vs telescoping lag screw for intertrochanteric fracture fixation

The purpose of this study was to compare fixation stability and lag screw sliding characteristics between 2 different hip-nail lag screw designs, a telescoping screwbarrel and a solid helical blade. Simulated, unstable, 4-part intertrochanteric hip fractures were created in 6 pairs of cadaveric femurs. Each nail type was randomly assigned within each femur pair. Lag screw sliding and inferior and lateral head displacements were measured following an applied static load of 750 N. Measurements were obtained before, during, and after cyclical loading with 750 N for 105 cycles. Ultimate failure strength was determined. After considering inferior head displacements, no significant differences between the 2 screw designs were found. Mean head displacement for the helical screw was 2.18 mm, compared with 1.87 mm for the telescoping screw (P = .731). A significant difference in the amount of lateral movement of the lag screws was found, however. The helical lag screws had mean lateral sliding of 2.68 mm, compared with 0.25 mm for the telescoping screws (P = .007). Neither of the lag screw constructs failed by screw cutout from the head. Both screw designs provide similar fixation strength for stabilization of 4-part intertrochanteric fractures. Both the telescoping lag screw and the helical blade facilitate fracture collapse, but the telescoping lag screw also minimizes lateral projection of the screw from the nail. This advantage may help minimize postoperative lateral soft-tissue impingement.     

Helical blade versus sliding hip screw for treatment of unstable intertrochanteric hip fractures: a biomechanical evaluation

OBJECTIVE: To compare the fixation stability in the femoral head with sliding hip screw versus helical blade designs for unstable, intertrochanteric hip fractures. METHODS: A simulated, unstable intertrochanteric hip fracture was created in six pairs of cadaveric femurs. One of each pair was treated using an intramedullary nail with a sliding hip screw (ITST) for femoral head fixation and the other was treated with a nail with a helical blade (TFN). Each specimen was cyclically loaded with 750N vertical loads applied for 10, 100, 1000 and 10,000 cycles. Measurements for femoral head displacement, fracture fragment opening and sliding were made. Specimens were then loaded to failure. RESULTS: There was significantly more permanent inferior femoral head displacement in the ITST samples compared to the TFN samples after each cyclic loading (all p values<0.05). There was significantly more permanent fracture site opening and inferior displacement in the ITST group compared with the TFN group at 1000 and 10,000 cycles (p<0.05). Final loads to failure were not significantly different (p=0.51) between the two treatment groups. Nine specimens demonstrated fracture extension into the anteromedial cortex and subtrochanteric region and three specimens, which had an ITST implant, demonstrated a splitting fracture of the femoral head. CONCLUSION: This study demonstrated that fixation of the femoral head with a helical blade was biomechanically superior to fixation with a standard sliding hip screw in a cadaveric, unstable intertrochanteric hip fracture model.     

Treatment of stable extra-capsular hip fractures with a sliding screw versus short gamma nail: a retrospective study of 102 patients

This is a retrospective study of 102 patients with intertrochanteric hip fractures comparing the operative results of short gamma nail? fixation with the sliding hip screw. The average patient age in the study is 83 years (range 52–94 years) with 87% females. The transfusion requirements between the two groups did not differ but a slightly larger decrease in hemoglobin levels was seen at 48 h in the gamma nail group. In neither group were there any intra-operative fractures or infections which led to a return to the operating room. The average length of stay for both groups was identical at 6.9 days. Twenty-seven short gamma nail patients and 18 compression hip screw patients were followed for 6 months. There were no instances of cut-out in either group but the short gamma nail group had middle/middle lag screw placement on the AP and lateral views more often than the compression hip screw (50%) group at 6 months. We conclude that the short gamma nail can be used effectively for the fixation of intertrochanteric hip fractures without the occurrence of potentially devastating complications such as intraoperative femur fracture, periprosthetic fracture or lag screw cut-out.     

Migration of the lag screw within the femoral head: a comparison of the intramedullary hip screw and the Gamma Asia-Pacific nail

OBJECTIVES: To study the functional difference in the performances of sliding femoral head screws by comparing the displacement of the screw in relation to the femoral head in hips treated with the Gamma Asia-Pacific nail (GN) and hips treated with the intramedullary hip screw (IMHS). STUDY DESIGN: Retrospective review of prospectively collected data. METHODS: Displacement of the femoral head screw in relation to the femoral head was measured in fifty-six elderly patients with intertrochanteric fractures who were treated with an IMHS or GN. Displacement of the femoral head screw was determined by comparing screw position in the immediate postoperative radiograph with a film taken 3 months after surgery. RESULTS: In the GN group, significant displacement of the screw was observed with 3.8 +/- 3.8 percent translation in the horizontal axis (P < 0.005) and 4.3 +/- 5.1 percent displacement in the vertical axis (P < 0.05) in comparison with the diameter of the femoral head. In comparison, displacement of the femoral head screw was not observed with the IMHS (P = 0.48 for horizontal, P = 0.18 for vertical). Total displacement of the femoral head screw in relation to the femoral head in the GN was twice that observed in the IMHS (P < 0.001). CONCLUSION: These results indicate that the displacement of the femoral head screw of the IMHS was less than the lag screw of the GN. However, it is still unknown whether this smaller displacement of the IMHS is clinically significant for reducing the rate of screw cut-out after surgery.     

Intertrochanteric hip fractures treated with the trochanteric fixation nail and sliding hip screw

The primary treatment options for intertrochanteric hip fractures are a sliding hip screw (SHS) and an intramedullary device, with each having its own advantages and disadvantages. The authors retrospectively compared all intertrochanteric hip fractures between 2003 and 2005 using a cephalomedullary nail--the trochanteric fixation nail (TFN)--to those using a SHS. Outcome measures included the following parameters: age, gender, fracture classification, operation time, blood loss, transfusions, complications, follow-up, length of stay, and hospital cost. A total of 95 patients were included in the study (51 SHS and 44 TFN). The two groups were similar in age (p = .52), blood loss (p = .20), follow-up (p = .13), length of stay (p = .63), and hospital costs (p = .70). The TFN procedure required shorter operative times (56.5 min, p < .004) and was used in more complex fracture patterns (p < .03). The SHS group had fewer blood transfusions (1.2 units, p < .0008). The SHS group had a higher complication rate of 19.6%, versus the TFN group's 11.4% rate (p = .13). The TFN is an appropriate and acceptable treatment method for intertrochanteric hip fractures.     

Locking plates increase the strength of dynamic hip screws

INTRODUCTION: Failure of a dynamic hip screw (DHS) fixation leads to decreased mobility of the patient and frequently to a decrease in general health. The most common mode of failure of a DHS is cut out of the lag screw from the femoral head. The second most common mode of failure is lift-off of the plate from the femur. The aim of this laboratory-based experimental study was to determine whether a DHS secured to an osteoporotic femur with a locking screw plate would provide a stronger construct than the standard DHS plate. METHOD: The standard DHS design was compared to a DHS with fixed angle locking screws holding the DHS plate to the femur. Standard dynamic compression plates (DCP) and locking compression plates (LCP) were attached to synthetic, osteoporotic bone. A load was applied to replicate the forces occurring following the fixation of unstable, intertrochanteric hip fractures. A bracket on the proximal end of the plate replicated the lag screw in the femoral head. The constructs were cyclically loaded by a screw-driven material-testing machine and the number of cycles before failure occurred was determined. RESULTS: The mean number of cycles to failure for the locking plate construct was 2.6 times greater than for the standard screw construct (285 versus 108 cycles, respectively p=0.016). CONCLUSION: A dynamic hip screw with fixed angle locking screws would reduce the risk of DHS failure. A locking screw DHS would be particularly useful in patients with osteoporotic bone, and in patients with less stable fracture configurations.     

Single screw type of lag screw results higher reoperation rate in the osteosynthesis of basicervical hip fracture

BackgroundBasicervical hip fractures are relatively rare with greater biomechanical instability compared to the other types of hip fractures. Several studies have reported ambivalent surgical outcomes of basicervical hip fractures. The purpose of this multicenter study was to analyze surgical outcomes of basicervical hip fractures according to the fixation type of proximal femur and lag screw type.MethodsAmong 3220 hip fractures, 145 were classified as basicervical hip fractures. Of those, 106 patients treated with osteosynthesis were included to analyze the surgical complications according to fixation type of proximal femur: sliding hip screw(SHS) and cephalomedullary nail (CMN) groups. Surgical complications including the excessive displacement of fracture and the occurrence of reoperation were evaluated at the final follow up. We further evaluated surgical complications according to lag screw type with subgroup analysis in CMN group: single screw type, blade type and two integrated screw type.ResultsTen patients (9.4%) sustained surgical complications (5 excessive displacements and 5 reoperations). For fixation type of proximal femur, SHS group showed higher tendency of excessive displacement despite no statistical difference between the two groups (p = 0.060). For lag screw type with subgroup analysis in CMN group, single screw type showed statistically high rates of reoperation compared to the other types of lag screw (p = 0.022).ConclusionBasicervical hip fractures treated with osteosynthesis resulted to high rates of surgical complications in this study. However, they could be drastically reduced if CMN with blade type or two integrated screw type were used in the osteosynthesis of basicervical hip fractures.     

Basicervical versus intertrochanteric fractures: an analysis of radiographic and functional outcomes

This retrospective study compared the long-term stability and functional outcomes of basicervical versus intertrochanteric fractures, and evaluated the use of an additional derotational screw in the treatment of basicervical fractures. Sixty-six patients (28 with basicervical fractures and 38 treated for stable and unstable intertrochanteric fractures) were identified. All intertrochanteric fractures were treated with a sliding hip screw. Basicervical fractures were treated with a sliding hip screw with or without a derotational screw. Radiographically measured fracture collapse and tip-apex distance were measured at least 6 weeks after surgery; SF-36 score and Functional Recovery Score data was collected at least 1 year after surgery. The proportion of fractures with > 10% collapse was significantly greater in the basicervical group than the subset of stable intertrochanteric fractures (P = .009), but not than the subset of unstable intertrochanteric fractures. The mean SF-36 bodily pain section domain was greater (less pain) in the basicervical group than the unstable intertrochanteric group (P = .02). No other significant differences in SF-36 scores were noted between the basicervical and either intertrochanteric group. Basicervical fractures collapse more than stable intertrochanteric fractures, suggesting that they may have greater biomechanical instability. This instability, however, does not translate into clinically significant decreases in functional outcome. Using a derotational screw with a sliding hip screw does not affect fracture stability or clinical outcome.