Proximal Femoral Nail Asia (PFNA)
Unstable trochanteric fractures, mainly due to osteoporosis, are a surgical challenge worldwide. However, significant regional variations are apparent in both the size and the characteristics of the problem. For example, it is known that East-Asians have different geometric proportions to Caucasians, resulting in complications due to a mismatch when using standard implants.
The Proximal Femoral Nail Antirotation (PFNA) Asia
To help cope with the differences described above, an Asian version of the existing Proximal Femoral Nail Antirotation (PFNA) was developed and introduced into the market. The PFNA Asia (also known as PFNA II) (Fig 1) has a proximal diameter of 16.5 mm, Caput Collum Diaphyseal (CCD) angles of 125 or 130, a range of lengths (short: 170 mm, 200 mm; long: 300 mm420 mm) and distal diameters (9 mm12 mm) with an adapted geometry, i.e., a flat lateral side, a straighter tip point, and medial-lateral bending of 5.
Study Rationale and Aims
While few previous studies have been conducted to compare the standard PFNA with other implants in the treatment of trochanteric fractures in Asians, no prospective study had focused on the effect of the PFNA Asia in the Asian population with respect to a detailed complication analysis.
The primary focus of the AOTrauma Japan multicenter case series study was safety, examined by assessing the 1-year local bone/fracture and implant/surgery complication rates in patients treated with the PFNA Asia. In addition, secondary outcomes focused on assessing function and quality of life-related patient outcomes, operative handling by the surgeon, potential mismatches between the femur and implant, anatomical restoration, and prognostic factors associated with the occurrence of complications.
The clinical investigation was performed in 20 Japanese hospitals over a three year period. The study population was 176 patients aged 65 years and older with a radiologically-confirmed, unstable, closed trochanteric fracture, sustained seven days or less before primary fixation treatment with the PFNA Asia.
Preliminary results and conclusion
Patient functional outcomes and health-related quality of life were similar between the pre-injury and final follow-up evaluations, and surgeons were highly satisfied with the implant and its handling. There is also a large societal benefit to enabling patients of advanced age that have sustained an unstable trochanteric fracture to return to their preinjury residential status.
The preliminary results from this study highlight the importance of having implants designed for older Asian patients available to surgeons in the region.
A manuscript on the study is currently in preparation. More information on the study methodology is available from www.ClinicalTrials.gov under the identifying number: NCT00873548.
Features of the Proximal Femoral Nail Antirotation (PFNA ) Asia
The Proximal Femoral Nail Antirotation (PFNA), with its helical blade concept, is a state-of-the-art treatment method for proximal femoral fractures, providing rotational and angular stability with one single element. The intramedullary nail acts as an internal splint that controls but does not prevent micromovements of the bone fragments. The PFNA provides relative stability, leading to indirect healing through callus formation.
With the PFNA Asia, the proximal-lateral portion of the nail has been narrowed to prevent jamming with the lateral cortex, and to facilitate smooth insertion of the nail.
The bending point was shifted by 5 mm proximally, compared to the standard PFNA, also helping with smoother nail insertion. The valgus angle is 5 with PFNA Asia, compared to the standard PFNA 6.
Case 1: Woman with fall injury
Cases provided by Takeshi Sawaguchi, Toyama, Japan.
A 78-year-old Japanese patient fell while at her home and sustained an AO 31-A2.1 injury (see Fig. 1).
She was operated on the next day and fixed with a PFNA Asia (size: extra small, angle 130 degrees, distal diameter: 9 mm, blade length 100 mm) (Fig 2a). Good reduction and stable fixation were obtained.
Full weight-bearing gait was allowed on the second postoperative day. There was an uneventful postoperative course, and good union was obtained at three months after surgery (Fig 2b).
Case 2: Elderly patient with fall injury
An 85-year-old Japanese woman fell down at her home. She sustained an AO 31-A2.1 fracture. The images indicate various stages of the operation, using the PFNA Asia.
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