Reply to reviewer comments 1
Line 112 – The flexor retinaculum is found over the carpal tunnel and should not be
incised during distal radius exposure.
Reply: Agree! Omitted already.
Line 113-114 – Can you elaborate what structures you may need to go through
or retract before you expose the pronator quadratus fully?
Reply: The FCR approach was used in this study. Namely, a longitudinal incision about
5 cm was made over the tendon of flexor carpi radialis (FCR). As the palmar
cutaneous branch of the median nerve is almost always ulnar to the FCR tendon, the
FCR tendon is then exposed by releasing its superficial sheath sharply.
In addition, when releasing the sheath, one must be careful distally near the proximal
wrist crease as the superficial branch of the radial artery crosses superficial to the
sheath and runs from ulnar to radial. Upon releasing the FCR sheath, the FCR tendon
is retracted radially. The deeper sheath and fascia under the FCR
tendon are then released. At this point, dissection is done between the radial fascia
and the FPL (flexor pollicis longus) muscle that runs deep to the fascia. The radial
artery runs radial to the FCR tendon and superior to this fascia. Thus, when the radial
fascia is retracted, the radial artery is protected. The FPL muscle must then be bluntly
dissected and ulnar retraction be performed. The bed of the FCR tendon sheath was
incised in line with the skin incision. Blunt dissection was then preformed to expose
PQ.
Line 116 – Do you perform brachioradialise muscle insertion release?
Reply: For most of the cases it is not necessary to release brachioradialise muscle
insertion.The flexor carpi radialis tendon is again retracted ulnarly, its gliding floor is
divided longitudinally, and the brachioradialis tendon is retracted radially.
Line 116 – Can you please describe how the volar capsulotomy is performed?
This is important because of the risk of injury to the radioscaphocapitate
ligaments and the radiolunate ligaments.
Reply: Usually, a 21 gauge needle was used to check the distal border of the scaphoid
and lunate fossa of radius. A minimal capsulotomy was performed to make sure the
position as the reference point of measurement.
Line 119 – Can you elaborate how the 2 K wires are positioned for temporary
stabilization?
Reply: The fracture is distracted and the achieved closed reduction is checked by
fluoroscopy. When a good reduction has been achieved it is temporarily stabilized
with two 1.8 mm Kirschner wires driven into the radial styloid in a distal to proximal
direction .
Line 122-126 – I think it would be of great benefit if you can diagrammatically
illustrate how the measurements are made in a drawing or in a photo. Also, could
you elaborate whether the measurements are projectional or along the surface of
the bone?
Reply: A vernier caliper was used to measure the distance along the surface of the
bone. A diagram(Fig. 1) illustrates the measurements in this study.
Fig. 1. A diagram demonstrates the relationship of distal radius and measurement of
pronator quadratu, distance from distal edge of pronator quadratus to lunate or
scaphoid fossa. Likewise, the distance from fracture site to lunate or scaphoid fossa
could also be measured. PQ:pronator quadratus muscle. P-L:distance from pronator
quadratus to lunate fossa, P-S: distance from pronator quadratus to scaphoid fossa
Line 128 – 129 – Can you tell us if there is any tips that you use to help to align
the longitudinal limb of the plate?
Reply: The longitudinal limb of the plate was lined up with the radial shaft, and the
position of the plate was adjusted under fluoroscopy. The more perfect alignment
will be achieved then.
Line 131-133 – How did you manage to retract the distal edge of the PQ? Was
there a need to incise the soft tissue along the distal edge of the PQ to allow you to
retract the muscle?
Reply s: It is important to note that the fracture site is usually near distal edge of PQ
or slightly covered by the pronator quadratus so that it is not necessary to divide this
muscle. Gentle traction of PQ is enough.
Line 158-164 – I think a diagram to illustrate your results would be of great
benefit. Numbers like these may not give people much of an impression.
Reply: Thanks.
Table 1. The width of pronator quadratus and distances between pronator quadratus
or fracture site to the distal radial edge. PQ: pronator quadratus; PQ-lunate:distance
from pronator quadratus to lunate fossa; PQ-scaphoid: distance from pronator
quadratus to scaphoid fossa; Fracture-lunate: distance from fracture site to lunate
fossa; Fracture-scaphoid: distance from fracture site to scaphoid fossa.
Mean(mm)
Range(mm)
PQ width
37.2
30-49
PQ-lunate
16.2
12-19
PQ-scaphoid
17.6
11-29
Fracture-lunate
12.2
7.3-17
Fracture-scaphoid
13.2
9.4-18.8
Line 186-189 – Did you manage to see the deep and superficial head of the PQ during
your clinical study?
Reply :Although Stuart reported that the superficial head of the PQ muscle is the
prime mover in forearm pronation and the deep head is a dynamic stabilizer of the
distal radioulnar joint. In this study, we did not try to identify these two portions.
Others –
I think it would be good to briefly report on union rate and time to union as one of
the approaches of the PQ sparing technique is to preserve periosteal blood supply.
Reply :Union was achieved in all fractures. The PQ vascularity was preserved in this
technique. There is no statistical significance on union rate and time between PQ
sparing technique and PQ incision technique.
2. Please also report on the operative time and comment whether it took longer
to perform PQ sparing approach.
Reply: Although it could save time to repair PQ, checked the plate alignment took
some time. Totally, the operation time did not take shorter.
3. Functional outcome in terms of range of motion would also be good although it is
not an objective of the study.
Reply :Yes, I would like to demonstrate the functional outcome in another
manuscript.
4. Also, we would like to know what the post op rehabilitation regime is like and
whether it is different between the traditional approach versus the PQ sparing
approach.
Reply: Active motion of fingers and wrist are started at next day after surgery or 5
days after removal of temporary splint immobilization in some cases.
5. Can you tell us if you routinely use a drain and if this PQ approach makes a
difference in drain use.
Reply :We do not routinely use a drain in distal radiu s fracture. The PQ approach
should make no difference in drain use.
6. Finally, could you show some x-rays of the results and also comment on plate
position in your cases and whether plate alignment is likely to be better or worse in
the PQ sparing approach.
Reply :We did not compare plate alignment in the PQ sparing approach or PQ
repairing approach, but we believe there will be no apparent difference.