Therapeutic Outcomes of Low-level Laser Therapy for
Closed Bone Fracture in the Human Wrist and Hand
Running title: Closed Bone Fracture Treated by Low-level Laser
Abstract
Objective: The therapeutic outcomes of low-level laser therapy (LLLT) on closed
bone fractures (CBFs) in the wrist and hand were investigated in this controlled study.
Background Data: Animal research has confirmed that LLLT increases osteocyte
quantity; however, little research has been conducted to determine the effect of LLLT
on the treatment of human bone fractures. Methods: In this study, the therapeutic
outcomes of administering 830 nm LLLT to treat CBFs in the wrist or hand were
examined. Fifty patients with CBFs in the wrist and hand, who had not received
surgical treatment, were recruited and randomly assigned to two groups. The laser
group underwent a treatment program in which 830 nm LLLT (average power 60 mW,
peak power 8 W, 10 Hz, 600 s, and 9.7 J/cm2 per fracture site) was administered 5
times per week for 2 weeks. Participants in a placebo group received sham laser
treatment. The pain, functional disability, grip strength, and radiographic parameters
of the participants were evaluated before and after treatment and at a 2-week
follow-up. Results: After treatment and at the follow-up, the laser group exhibited
significant changes in all of the parameters compared with the baseline (p < 0.05).
The results of comparing the two groups after treatment and at the follow-up indicated
significant between-group differences among all of the parameters (p < 0.05).
Conclusion: LLLT can relieve pain and improve the healing process of CBFs in the
human wrist and hand.
Introduction
Wrist and hand fractures occur when an extrinsic factor, such as trauma, or an
intrinsic factor, such as osteoporosis causes a partial or total break in the integrity and
consistency of a bone.1 Surgeons typically diagnose the type and stability of the
fracture based on physical examinations and radiographic findings.2, 3 A displaced or
complicated fracture is managed using internal or external fixation.1 Non-displaced or
relatively stable types of fracture, e.g. closed bone fractures (CBFs), are managed
using splinting or conservative treatments to support the healing bone.2 To rehabilitate
patients with CBFs in the wrist or hand without using surgical fixation, treatment
focuses on maintaining the range of motion, reducing edema, promoting bone healing,
and decreasing pain.2 Conservative treatments for CBFs in the wrist or hand generally
involve providing patients with casts, splints, and medication.3 However, such
treatment does not actively involve the fracture site. Orthopedists have therefore
endeavored to develop other suitable treatment methods and tools.3
As a modality of rehabilitation, low-level laser therapy (LLLT) has been
suggested for clinical use.4 LLLT can improve the repair process of injury tissues, and
reduces inflammation and pain.4 Previous studies using cellular and animal
experiments have revealed that LLLT is associated with improved bone healing, and
that clinical trials in humans are warranted.5,6,7 Several cellular studies have reported
that LLLT positively affects bone cells,6,7 but to date studies on the clinical use of
LLLT are lacking. In an animal study, Lirani-Galvao et al. demonstrated that LLLT
increased osteoblast activity and bone density by boosting the activation of
osteoblasts in later stages of bone repair.8, 9 Base on these results, it is reasonable to
presume that LLLT can reduce the time required for a fracture to heal. The use of
LLLT may have bone healing utility for CFB patients.
The wavelengths range of LLLT from 600 to 1000 nm with power densities from
1 mW/cm2 to 5 W/cm2, and treatment times typically range from 10 s to 10 min,
although certain studies have introduced wavelengths and treatment times outside
these ranges.9,10 The outcomes of LLLT depend on irradiation parameters (wavelength,
power density, and pulses) and irradiation time, often referred to as the“dose”and
expressed as energy (J) or energy density (J/cm2). In a review study conducted by
Bjordal et al., no substantial effects of LLLT were reported because the energy
delivered was inappropriate; the dose was either too high or too low.10 LLLT at
wavelengths between 810 and 830 nm, and dosages between 6 and 10 J, was
recommended to induce anti-inflammatory effects to treat orthopedic diseases.11
Studies have suggested that a laser wavelength of 830 nm can deeply penetrate tissue
and that satisfactory absorption can be achieved, thereby inducing favorable clinical
results.10-11 However, based on our research, no studies investigating the effect of
LLLT on bone fractures in humans have been performed. Therefore, the therapeutic
outcomes of applying LLLT (830 nm; 9.7 J/cm2) to CBFs in the human wrist and hand
were examined in this study.
Methods
Patients diagnosed with wrist and hand fractures were recruited and referred to the
Division of Orthopedics at Da-Chien Hospital in Miaoli, Taiwan. The orthopedist
confirmed that no wounds had occurred over the fracture site, and then classified the
fractures as grade II trauma injuries based on the Abbreviated Injury Scale.12 This
clinical research proposal was confirmed and approved by the hospital. The inclusion
following criteria were used to select patients: (1) the patients had been diagnosed
with a CBF, but had not been treated by undergoing an operation or splinting; (2) the
fracture was discovered in the phalanges, or the metacarpal, carpal, distal ulna, or
distal radial bones; and (3) the patient had never received LLLT before. The Research
Ethics Committee of the Institutional Review Board for Human Subjects Research
approved all of the study protocols (No. DC-ETHICS-97090701). After being
informed of the study in detail, all of the participants gave informed consent for
treatment. The participants were recruited between July 2009 and August 2011, and
their injuries were classified according to the gradation of fractures defined by the
Orthopaedic Trauma Association.13 During the 4-week study, the participants were
instructed to cease taking all anti-inflammatory drugs, and other treatments, such as
undergoing physical therapy and taking Chinese medicine, were also disallowed.
Study design
The experiments were conducted on a double-blind basis, and the participants
were randomly assigned to one of two groups. The participants in the laser group
received LLLT. In this group, a laser device (Painless Light PL-830, Advanced Chips
& Products Corp., USA) was used to emit a laser beam focused on an area of 370
mm2 using two inbuilt laser diodes. The distance between the inbuilt laser diodes in
the output head was 2.5 cm. The device specifications are shown in Table 1. The
treatment dose, expressed as energy density, was 9.7 J/cm2. The laser device made
direct contact with and irradiated the skin of the fracture site, ensuring that the input
dose was stably sent into the unit area. The participants in the placebo group, in which
there was no laser output, received sham laser treatment emitted onto the fracture site.
The participants did not know whether they were receiving the laser or sham laser
treatments during the study.
Clinical assessments were performed by a physician. Based on X-ray images, a
physician palpated potential suitable sites for exposure to the treatment. A belt was
used to hold the output head of the laser device above the fracture site (Fig. 1), and
the area of each site was irradiated using a treatment dose of 9.7 J/cm2. The laser
device was equipped with a timer, which monitored and automatically turned off the
power after 600 s, after which an audible signal was issued to alert the participant that
the treatment session had ended. The treatment was administered to the wrists or
hands of the participants in both groups for 600 s per fracture site by a physical
therapist, once a day, 5 days a week. Each treatment course lasted 2 weeks. The only
difference between the treatments for the placebo and laser groups was that the
placebo treatment employed the laser device without generating a laser output. The
laser devices, which were provided by the study investigator to the physical therapist,
appeared identical. Although the physical therapist was informed which laser devices
were used to treat which groups, the physical therapist was not informed that the sham
laser device did not generate an energy output, to avoid psychological effects.
Assessments were conducted before and after LLLT, and at the 2-week follow-up. The
assessment devices included a digital prehension device and a digital imaging system,
calibrated using commercial agents (Good Line Corporation and General Electric
Company, Taiwan) at the beginning of the study. The physician and physical therapist
did not know whether the participants were members of the laser or placebo groups.
Assessments
Pain Measurement: The fracture site of each participant was identified based on
X-rays and physical examinations. Thereafter, the physician manually and gently
pressed the fracture site to measure the intensity of the participant’s pain, and the
participant was asked to assess his or her pain by using a visual analog scale (VAS).
Quick Questionnaire for Disabilities of the Arm, Shoulder, and Hand (Quick
DASH): Quick DASH is a standardized measure used to record the physical function
of and the symptoms exhibited in a patient’s upper extremies.14 It is a useful tool for
assessing the therapeutic outcome of patients with traumatic hand injuries, and has
strong reliability and validity for assessing the functional ability of wrists and hands.14,
15
The self-report questionnaire contains 11 items for evaluating the difficulty of
specific activities, of which 4 items address the patient’s ability to work, and 4 items
concern the patient’s ability to play sports. Each item is measured based on a 5-point
response scale. The total scores are calculated using [(the sum of n responses/n) – 1] 
25, where n is equal to the number of completed responses. The total scores range
from 0 (no disability) to 100 (most severe disability).
Hand and finger grip strength: The strength of each participant’s finger grip was
assessed based on the power of their tri-digital pinch, which was measured
individually, using the Jamar Hydraulic Pinch Gauge (Lafayette Instrument Company,
USA). Hand grip strength was measured using the Jamar Hydraulic Hand
Dynamometer (Lafayette Instrument Company, USA). Participants sat in a chair,
keeping their elbows flexed at 90° (approaching the chest).16 The mean scores of both
groups for these 5 separate measurements were recorded, with a rest interval of 5 min
between each measurement.
Radiographic Signs of Bone Healing: Anteroposterior and lateral views of the
injury were examined using X-rays. The X-ray image in Fig. 2 shows a participant’s
right wrist and hand before and after LLLT. To assess the progress of healing, the
fracture site of each participant was evaluated using a digital imaging system (Nu
Film Versions 4.05, Thinking System Corporation, USA). The radiographic signs
of bone healing were evaluated using two parameters.17 The first parameter was the
fracture line (FL), and healing had occurred if the FL present in the original fracture
was absent. The second parameter indicating healing was detectable cortical bridging
(CB), defined as the formation of calluses and the gradual disappearance of the
interruption of the cortex at the fracture site. The radiographic measures were
evaluated and recorded by the same physician in each case, and the same physician
calculated the differences between the measurements.