Treatment of Unstable Trochanteric Femur Fractures: Proximal Femur Nail Versus Proximal Femur Locking Compression Plate

The American Journal of Orthopedics. 2017 March;46(2):E116-E123

April 11, 2017|The American Journal of Orthopedics

Ashutosh Kumar Singh, MBBS, MS;Nidhi Narsaria, MBBS, MD;Arun G. R., MBBS, MS;Vivek Srivastava, MBBS, MS

Unstable trochanteric femur fractures are common fractures that are difficult to manage. We conducted a prospective study to compare functional outcomes and complications of 2 different implant designs, proximal femur nail (PFN) and proximal femur locking compression plate (PFLCP), used in internal fixation of unstable trochanteric femur fractures. On hospital admission, 48 patients with unstable trochanteric fractures were randomly assigned (using a sealed envelope method) to treatment with either PFN (24 patients) or PFLCP (24 patients). Perioperative data and complications were recorded. All cases were followed up for 2 years. The groups did not differ significantly (P > .05) in operative time, reduction quality, complications, hospital length of stay, union rate, or time to union. Compared with the PFLCP group, the PFN group had shorter incisions and less blood loss. Regarding functional outcomes, there was no significant difference in mean Harris Hip Score (P = .48) or Palmer and Parker mobility score (P = .58). Both PFN and PFLCP are effective in internal fixation of unstable trochanteric femur fractures.

Take-Home Points

Both PFN and PFLCP are effective treatments for unstable trochanteric femur fractures.
PFN is superior to PFLCP only in terms of shorter incisions and shorter time to full weight-bearing.
Both devices have good long-term functional outcomes.
Complication rates in unstable trochanteric fractures treated with both implants are comparable.
Larger randomized controlled multicenter studies are needed to further evaluate and compare both implants in displaced unstable trochanteric femur fractures.

Trochanteric fractures are among the most widely treated orthopedic injuries, occurring mainly as low-energy injuries in elderly patients and high-energy injuries in younger patients.^1,2 About half of these injuries are unstable.³ According to the AO/OTA (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association) system, trochanteric fractures can be classified stable (AO/OTA 31.A1-1 to 31.A2-1) or unstable (AO/OTA 31.A2-2 to 31.A3.3).^4,5 For surgical fixation of trochanteric femur fractures, various internal fixation devices have been used, either extramedullary (EM) or intramedullary (IM).⁶ The dynamic hip screw (DHS) is the implant of choice in the treatment of stable trochanteric femur fractures (AO/OTA 31-A1), as it provides secure fixation and controlled impaction.⁷ Mechanical and technical failures continue to occur in up to 6% to 18% of cases of unstable trochanteric fractures treated with DHS.⁸ Excessive sliding of the lag screw within the plate barrel results in limb shortening and distal fragment medialization, which are the main causes of these failures.^9,10 Dissatisfaction with DHS use in unstable fractures led to the use of IM nails. The various IM devices available are condylocephalic (Ender) nails and cephalomedullary nails, such as gamma nails; IM hip screws; trochanteric antegrade nails; proximal femoral nails (PFNs); and trochanteric fixation nails.^11,12 Unstable trochanteric fractures treated with these IM fixation devices have had good results.^12-14Because of their central location and shorter lever arm, IM nails decrease the tensile strain on the implant and thereby reduce the risk of implant failure and provide more efficient load transfer while maintaining the advantage of controlled fracture impaction, as in DHS.^15,16 According to some authors, IM nail insertion theoretically requires less operative time and less soft-tissue dissection, potentially resulting in decreased overall morbidity.^15,16 PFN is one of the most effective fixation methods used to treat unstable trochanteric femur fractures.¹⁷ However, it is associated with various technical problems and failures, such as anterior femoral cortex penetration (caused by mismatch of nail curvature and intact femur), lag screw prominence in the lateral thigh, creation of a large hole in the greater trochanter (leading to abductors weakness), and potential for the Z-effect.^18,19 Studies have compared PFN with the Less Invasive Stabilization System-Distal Femur (LISS-DF) in the treatment of proximal femur fracture, and the clinical results are encouraging.^20,21Recently, the proximal femoral locking compression plate (PFLCP) was introduced as a new implant that allows for angular-stable plating in the treatment of complex comminuted and osteoporotic intertrochanteric fractures.^22,23

To our knowledge, our study is the first to compare functional outcomes and complications of unstable trochanteric fractures treated with PFN and those treated with PFLCP. We hypothesized that both PFN and PFLCP would provide good functional outcomes with acceptable and comparable complications in the treatment of unstable trochanteric fractures.

Materials and Methods

The protocol for this prospective comparative study was approved by the Institutional Review Board at Mayo Institute of Medical Sciences. Informed consent was provided by all patients. A power analysis with power of 90% to detect a Harris Hip Score (HHS) difference of 10 as being significant at the 5% level, and with a 10% to 15% dropout rate, determined that a sample size of 50 patients was needed. Each group (PFN, PFLCP) required at least 25 participants. From April 2009 to June 2011, 74 patients with unilateral closed unstable trochanteric fractures were admitted to our hospital. Of these patients, 48 met our inclusion criteria and were included in the study. A sealed envelope method was used to randomly assign 24 of these patients to PFN treatment and the other 24 to PFLCP treatment. One patient died of causes unrelated to an implant during the study, and 2 were lost to follow-up (telephone numbers changed). The remaining 45 patients (23 PFN, 22 PFLCP) reached 2-year follow-up.

Inclusion criteria were unilateral, closed unstable trochanteric fractures, and age over 18 years. Exclusion criteria were bilateral fractures, polytrauma, pathologic fractures, open fractures (American Society of Anesthesiologists [ASA] grade 4 or 5),²⁴ and associated hip osteoarthritis (Kellgren-Lawrence grade 3 or 4).²⁵ We collected data on demographics, operative time, incision length, intraoperative blood loss (measured by gravimetric method), hospital length of stay (LOS), and time to full weight-bearing. Mean (SD) age was 58.3 (9.3) years for the PFN group (range, 19-82 years) and 60.5 (8.1) years for the PFLCP group (range, 20-84 years).

The groups were similar in terms of sex proportion (P = .42), fracture side (P = .82), fracture type (P = .15), time from injury to surgery (P = .24), and Palmer and Parker mobility (PPM) score (P = .26). The Singh index was used to evaluate osteoporosis grading; there was no significant difference between groups (P = .48). The AO/OTA system was used to classify fractures. Only AO type 31.A2 and 31.A3 fractures (unstable trochanteric fractures) were included in the study (Table 1).

Before surgery, each patient’s standard plain radiographs (1 anteroposterior [AP], 1 lateral) were evaluated. Patients underwent surgery as soon as their general medical condition allowed. Surgery was performed through a lateral approach with the patient supine and in traction on a fracture table. PFN patients received 2 femoral neck screws (DePuy Synthes) (Figures A-D), and PFLCP patients received PFLCP (DePuy Synthes) in a fashion similar to that described in AO internal fixation manuals.

Intraoperative reduction was assessed and graded good, acceptable (5°-10° varus/valgus and/or anteversion/retroversion), or poor (>10° varus/valgus and/or anteversion/retroversion).²⁶A standard postoperative protocol was followed. Knee and ankle exercises were started on postoperative day 1. Non-weight-bearing walking with bilateral axillary crutches was started after surgery, usually on postoperative day 3 to 5, as tolerated. Follow-up was monthly the first 3 months, then every 3 months until 2 years. At each follow-up, patients were assessed clinicoradiologically; functional outcome scores and complications were assessed and reported; and AP and lateral radiographs were examined for implant position and signs of fracture union. Progressive weight-bearing was started after 6 weeks, initially with 25% of the patient’s weight. Walking with gradually increasing weight-bearing was allowed, provided that reduced and stabilized fracture position remained unchanged, and there were clinicoradiological signs of bone healing (no pain, swelling, or tenderness at fracture site clinically; invisible fracture lines on radiographs). Walking ability was assessed with a PPM score (maximum, 9 points), which covered 3 items, ability to walk indoors (1 item) and ability to walk outdoors (2 items).²⁷Overall patient outcomes were summarized using the HHS system (excellent, 90-100 points; good, 80-89 points; fair, 70-79 points; poor, <70 points).²⁸Evaluated complications included superficial wound infection (positive bacterial culture from above fascia), deep wound infection (positive bacterial culture from below deep fascia), nonunion, fixation failure (lag-screw penetration in joint, back-out or cut-out of femoral head, breakage of implant, nonunion of fracture, secondary loss of reduction), and complications unrelated to implant (deep vein thrombosis, bed sore, chest infection).

Absolute values of differences were used for statistical analysis. For categorical outcome variables (eg, reoperation reason and type), Pearson χ² test was used; for continuous variables (eg, pain, HHS), Student t test was used. Statistical significance was set at P = .05 (2-sided).

References

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