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| ORIGINAL ARTICLE |
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| Year : 2015 | Volume
: 6
| Issue : 1 | Page : 49-53 |
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The effect of low-intensity pulsed ultrasound therapy on fracture healing
Jagannath B Kamath, Nikil Jayasheelan, Babul Reddy, Shafeekh Muhammed, Amaranth Savur
Department of Orthopaedics, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India
| Date of Web Publication | 8-Dec-2014 |
Correspondence Address:
Nikil Jayasheelan
Department of Orthopaedics, Kasturba Medical College, Mangalore - 575 001, Karnataka
India
 Source of Support: Family for fi nancial support, Conflict of Interest: None  | Check |
DOI: 10.4103/0975-9727.146426
Purpose: Multiple methods of accelerating fracture healing have been proposed and some are approved for use in the clinical settings. A low intensity (30 nW/cm 2 ) pulsed ultrasound (LIPUS) signal will promote fracture healing. This study is conducted to determine the effect of LIPUS on fresh fracture healing. Materials and Methods: Out of the 60 patients with diaphyseal fractures of the tibia and femur fixed with an interlocking nail, 33 received LIPUS and 27 were kept as control. Ultrasound treatment was started three days after surgery, 20 minute sessions each day, for 30 days. The rate of fracture healing in the LIPUS group was compared with that of the control group. Six orthopedic surgeons and two radiologists analyzed the follow-up x-rays. Results: Five out of the six surgeons interpreted that there was significantly more callus formation and union in the LIPUS group compared to the control group, especially in the initial stage of healing. The need for dynamization decreased by 50% in the LIPUS group. Both radiologists interpreted that there was significantly more callus in the case where ultrasound was administered, when they evaluated the same with an diagnostic ultrasound scan at the fracture site. Conclusion: The present study establishes the relation between low intensity pulsed ultrasound therapy and fresh fracture healing, especially in the early stages. We strongly recommend the use of LIPUS as an adjunct therapy where the surgeon anticipates delayed union of the fracture. Keywords: Fracture healing, low intensity pulsed ultrasound therapy (LIPUS)
How to cite this article:
Kamath JB, Jayasheelan N, Reddy B, Muhammed S, Savur A. The effect of low-intensity pulsed ultrasound therapy on fracture healing. Muller J Med Sci Res 2015;6:49-53 |
How to cite this URL:
Kamath JB, Jayasheelan N, Reddy B, Muhammed S, Savur A. The effect of low-intensity pulsed ultrasound therapy on fracture healing. Muller J Med Sci Res [serial online] 2015 [cited 2023 Mar 20];6:49-53. Available from: https://www.mjmsr.net/text.asp?2015/6/1/49/146426 |
| Introduction | |  |
The global burden of injury is staggering and injuries are predicted to be the leading cause of death and disability over the next few decades. With fractures accounting for the majority of trauma in developing nations, novel therapies are desperately needed to optimize patient outcome. New developments in the biology and biomechanics of the musculoskeletal system, fixation devices, and soft tissue management have greatly influenced our ability to treat musculoskeletal injuries. Despite advances in fracture fixation and treatment, difficulties in fracture healing persist. Fracture nonunion is a source of disability and caries with its significant socioeconomic costs. Multiple methods of accelerating fracture healing have been proposed and some are approved for use in the clinical settings. Among these, the low intensity pulsed ultrasound has shown promising results in animal data and clinical settings. [1],[2],[3] Historically, the ultrasound has been contraindicated in the setting of fractures. This is largely due to early animal studies, showing that ultrasound treatment delayed or even damaged the healing bone. However, recent studies have shown that the effect of therapeutic ultrasonography on the healing bone is dictated by the intensity used. [3],[4] A high intensity continuous wave ultrasound signal used in animals is harmful, but a low intensity (30 nW/cm 2 ) pulsed ultrasound signal promotes fracture healing. This notion has been reinforced by positive findings (i.e., a shorter time to fracture healing) in controlled animal trials and uncontrolled human trials. [4],[5],[6],[7] The Food and Drug Administration (FDA) has recently approved the use of a low intensity ultrasound for the accelerated healing of fresh fractures and for the treatment of established nonunion.
This study focuses on the effect of low intensity pulsed ultrasound (LIPUS) on fresh fracture healing, which is a noninvasive, cost-effective, and non-cumbersome method, used for fracture healing.
This study was conducted to determine the effect of LIPUS on the fresh fracture healing of the femur and tibia and to determine whether stimulation with LIPUS reduces the radiological healing time of fresh diaphyseal fractures of the femur and tibia fixed with a reamed intramedullary nail.
| Materials and Methods | | |
The study was a prospective, randomized, short-term study, conducted in a medical college. Statistical significance was tested using student unpaired't' test. The study period was between October 2009 and April 2012. All patients between 20 and 60 years of age, who were treated for closed diaphyseal fracture of the tibia and femur with closed reduction and reamed intramedullary nail fixation were invited to participate in the study. Patients were excluded if the radiographs showed severe communition (Muller type B, C) at the fracture site and patients with segmental fractures, open fractures, pathological fractures, multiple fractures, as also patients with head injury. Fracture fixation was performed by reamed intramedullary nailing. The size of the nail was determined after reaming the canal until the reamer touched the cortical bone at the isthmus. A nail with diameter 1.0 mm smaller than the final reamer was inserted, the average nail diameter was 10 mm, with a range of 8-12 mm. The study was designed by allocating patients randomly to either of the two groups, in which one group received low intensity pulsed ultrasound therapy (LIPUS group) daily, for 20 minutes, for 30 days, and the other group treated as the control received no treatment other than surgical management. Once the patient was included in the study, a permanent marker was placed over the skin to indicate the exact fracture site by c-arm guidance during surgery. During the treatment sessions the transducer probe of the ultrasound machine was kept directly over the skin, which was marked earlier over the anteromedial side of the tibia and anterior aspect of the femur, after applying the ultrasonic coupling gel. Ultrasound treatment was started three days after surgery and consisted of 20-minute sessions each day, for 30 days. A timer in the Main Operating Unit monitored the treatment duration and made it possible to measure patient compliance. The machine used was BONE HEAL-100, developed by Technomed Electronics, Chennai, India. The treatment head module of the active device emitted an ultrasound signal that was composed of a burst width of 200 microseconds, containing a 1.5 MHz sine wave, with a repetition rate of 1 KHz and a spatial average temporal intensity of 30 milliwatts per square centimeter. The patients were followed up every fourth week for 16 weeks, for radiographic and sonographic evaluation. Standardized anteroposterior and lateral radiographs were obtained, to monitor fracture healing on each follow-up. Fracture healing was defined as the presence of a bridging callus of at least three cortices, on both views. The fracture union was assessed by six orthopedic consultants, by evaluating all femur and tibia radiographs taken at 4, 8, 12, and 16 weeks, for callus detection. All the surgeons were blinded about the study and they graded these x-rays from 0-10 points, according to the amount of callus and fracture union.
Ultrasound studies were obtained on each follow-up by using the 7.5 MHz and 10 MHz linear array transducers for the tibia and femur, respectively. Echogenicity of the soft tissue in the fracture gap was compared with the echogenicity of the tibialis anterior muscle for the tibia and vastus intermedius for the femur, and described as iso-, hypo-or hyperechoic. The other characteristic assessed was the visibility of the intramedullary nail in the fracture gap. Fracture healing was defined as progressive by the appearance of hyperechoic tissue filling the fracture gap, obscuring the view of the intramedullary nail in the fracture site. There was no attempt to quantify the quantity of the callus by sonological methods. These observations were made by two independent blinded radiologists, who were shown only the sonological pictures and not the patients. The time taken for fracture healing in the LIPUS group was compared with that of the control group by comparing the sonographic and radiographic images.
| Results | | |
Out of the 60 patients in the study, 33 patients received LIPUS and 27 were kept as control.
The demographic data of patients and type of the fractures are as given in the [Table 1], [Table 2], [Table 3] [Table 4] and [Table 5].
There was no significant difference between the two treatment groups with regard to any of the patient or fracture-related parameters.
Five out of the six surgeons interpreted that there was significantly more callus formation and union in the LIPUS group compared to the control group, especially in the initial stages of fracture healing, even though the final outcome of fracture was found to be same in the time taken to fracture healing. The average score in LIPUS the group was 6.5 in contrast to 3.5 in the control group, which was statistically significant. The effect of LIPUS on the femur fracture was more than in the tibial fractures, probably because of the good biological sleeve around the femur. Even though we conducted ultrasound detection of the calluses we could not quantify the calluses at the fracture site, so we could comment on fracture union only in terms of the ultrasound. However, it was observed that the ultrasound picked the early visible callus at the end of four weeks in the LIPUS group [Figure 1] compared to the control group [Figure 2], and the rate of healing, seen as the progressive appearance of hyperechoic tissue filling in the fracture gap obscuring the view of intramedullary nail was more enhanced in the LIPUS group [Figure 3] than in the control group [Figure 4] at the end of 12 weeks.
There was no significant difference between the two groups with respect to the type and rate of complications during the course of treatment. Two patients, one in each group, developed superficial wound infection, which was treated with drainage and antibiotics with the nail left in place, and it healed without sequelae. The need for dynamization in the LIPUS group (one patient) was 50% less when compared to the control group (two patients).
| Discussion | | |
We conducted this study because of several reports on the non-thermal effects of pulsed low intensity ultrasound on the normal fracture repair process. Another reason was that even though there were several in vitro cell model systems and animal studies [5],[7],[8] related to the effect of ultrasound on bone healing, only a small number of studies were available in the clinical setting related to the effect of ultrasound on fracture healing. [5],[7],[8],[9],[10],[11],[12],[13],[14] The patient and fracture characteristics in the two treatment groups were very similar, as shown with comparability analysis, except that the LIPUS group was under observation in the hospital for the initial four weeks, as inpatients, but not the control group. The portable treatment unit (Bone Heal-1000) was easy to use, including application of the coupling gel to the transducer, securing the treatment module, and the automatic stopping and buzzer alarm when the treatment time counted to zero. There were no complications or adverse reactions attributable to any aspects of treatment. Comparison of the results demonstrated that there was significantly more callus formation and a faster rate of union in the LIPUS group compared to the control group, especially in the initial stages of fracture healing, even though the final outcome of the fracture was found to be same in terms of time taken for fracture union. However, there was no difference in the fracture healing time in both study groups. In both groups, the fracture united radiologically by the end of 16 weeks except in three patients (one in the LIPUS group and two in the control group). We have for the first time included the assessment of callus formation using diagnostic ultrasound and proved that there was better callus formation in patients who underwent LIPUS compared to the control. This was confirmed by two consultant radiologists, who were completely blinded to the two methods [Figure 5].
The results of this study were comparable with the study conducted by Heckman et al. [9] and Kristiansen et al.,[10] where they reported a significant 38% decrease in time of fracture healing. The duration of fracture stimulation was more and the fracture was treated with a cast in contrast to our study, where the duration of stimulation was less and the fracture was internally fixed.
The present study contradicts the study conducted by Emami et al., [11] in which tibial fractures with a reamed intramedullary nail received active ultrasound (15 patients) and placebo (17 patients). They concluded that there was no difference in the fracture healing time between the two groups. The patient, fracture, and ultrasound characteristics were comparable in both studies. The sample size was more in our study (33 patients) and the duration of ultrasound therapy in our study was less (four weeks), when compared to the study by Emami et al., in which treatment continued for 10 weeks. However, we found that LIPUS was more useful in fractures surrounded by soft tissue vascular sleeve, as in case of the femur. If the same reason is extrapolated, LIPUS should also have a beneficial advantage in fractures involving the humerus, radius, and ulna.
| Conclusion | | |
The present study establishes the relation between low intensity pulsed ultrasound therapy and fresh fracture healing in the early stages of fracture healing and supports several randomized, controlled trials in the medical literature on the effects of fracture healing by LIPUS. It has been found that there is significantly more callus formation in the LIPUS group compared to the control group, especially in the initial stages of fracture healing. The effect of LIPUS on the femur fracture is more compared to that on the tibial fractures, probably because of the good biological sleeve surrounding the femur. In about 4-10% of the fresh fractures, impairment of the healing process may lead to delayed union or nonunion, requiring further surgical procedures. Therefore, we strongly recommend the use of LIPUS as an adjunct therapy, where the surgeon anticipates delayed union of the fracture. The need for dynamization has been decreased by 50% in the LIPUS group.
Furthermore, increasing the duration of therapy may decrease the time required for the union.
| Acknowledgment | | |
We acknowledge Technomed Electronics, Chennai, India, for providing the LIPUS machine for our study.
| References | | |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]
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