PFNA Asian Size (PFNA II)

Fig 1: PFNA Asia (PFNA II)

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 design of the PFNA was developed based on the anatomy of the Caucasian population. For the average Asian patient, the fit of these implants is not optimal. Therefore, cadaver studies using CT scans were performed to adapt the design of the PFNA to the anatomy of the Japanese and other Asian population.

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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.

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 better fit to the smaller trochanteric area and narrower intramedullary canal of the Asian population. It features a lateral flat surface which makes insertion easier and lowers the pressure on the lateral cortex. The bend has been reduced to 5° versus 6° compared to the PFNA. The proximal diameter has been reduced to 16.5 mm (versus 17.0 mm). Furthermore, the spiral blade diameter has been reduced to 10.3 mm.

The PFNA Asian size comes in four different distal diameters from 9–12 mm, each in three lengths (170, 200, and 240 mm*). The long PFNA Asian size (260–340 mm, with 20 mm increments) is available in two distal diameters of 9 and 10 mm. Additional lengths of 340–420 mm in 40 mm increments are available with a distal diameter of 10 mm. The blade is available in lengths of 75–120 mm in steps of 5 mm. Two versions of Caput Collum Diaphyseal (CCD) angles of 125° or 130° are available. The nail is made out of titanium aluminum niobium (TAN) and sterile packaged.

In addition, some selected instruments have also been specifically designed for the smaller stature of the population and to the needs of the Asian surgeons.

The PFNA Asian size is indicated for pertrochanteric fractures (Müller AO Classification 31-A1 and 31-A2), intertrochanteric fractures (31-A3), and high subtrochanteric fractures (32-A1). The long version is indicated for low and extended subtrochanteric fractures, ipsilateral trochanteric fractures, combination fractures in the proximal femur, and pathological fractures.

*The 240 mm nail comes in two different distal diameters 9 and 10 mm only.

Fig 2

Fig 3: The PFNA range.

Fig 4: Representations of a fitted PFNA (left) and PFNA Asia (right).

PFNA/PFNA-II Blade Extraction Set

The PFNA/PFNA-II blade extraction set is a special set containing instruments for the extraction of the PFNA/PFNA-II blade and received its AO TC approval in November 2009. Usually, the blade is removed by the extraction screw for PFNA blade. But in certain cases, especially in younger patients with good bone quality, the PFNA/PFNA-II blade may not be removable with the standard surgical technique and instrumentation. The new extraction set offers special instrumentation for potential issues such as damaged recess of blade, extracted end cap of blade, broken screw, extracted sleeve of blade, and parts of broken instruments in end part of blade.

Proximal Femoral Nail Removal Set

The proximal femoral nail removal set is a comprehensive set containing instruments for the removal of all proximal femoral nails as the trochanteric fixation nail (TFN short, standard, and long), the proximal femoral nail (PFN extra small, small, standard, and long), the proximal femoral nail antirotation (PFNA extra small, small, standard, and long), and PFNA-II (extra small, small, standard, and long). It received AO TC approval in November 2009.

The proximal femoral nail removal set contains general instruments for implant removal as well as all system-specific extraction instruments for the different proximal femoral nails. This prevents abort of surgery due to wrong set order or wrong identification of nailing system and avoids delays caused by missing or incorrect instruments.

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 5).

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 6a). 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 6b).

Fig 5: pre-op image

Fig 6a-b: post-op images

Case 2: Elderly patient with fall injury

Case provided by Takeshi Sawaguchi, Toyama, JP

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.

Fig 7a-f: various stages of the operation

Case 3: 90-year-old male, injured by fall down.

Case provided by Toru Sato, Okayana, JP

Fig 8a-b: Preoperative radiographs.

Fig 9a-b: Radiographs 2 weeks after surgery; patient could stand and walk with one cane.

Fig 10a-b: Radiographs 6 months postoperative.

Case 4: 77-year-old male.

Case provided by Takeshi Sawaguchi, Toyama, JP

Fig 11a-b: Preoperative radiographs.

Fig 12a-c: Postoperative radiographs.

Fig 13a-c: Radiographs 3 months postoperative.

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