Manipulation under anesthesia (MUA) involves a series of noninvasive mobilization, stretching, and traction procedures while the individual receives anesthesia (e.g., conscious sedation, general anesthesia). Typically, reflex muscle guarding and pain limit the ability of a professional provider to appropriately break up joint and soft tissue adhesions. In addition to reducing the pain associated with treatment, anesthesia induces muscle relaxation and circumvents reflex spasms. This allows improved range of motion (ROM) in restricted axial and appendicular articulations.
Since the 1930s, spinal MUA (SMUA) has been performed by professional providers with the assistance of anesthesiologists. However, complications arising from general anesthesia and high-amplitude manipulation procedures resulted in the decreased use of SMUA. In the 1990s, the advent of safer anesthesia agents allowing for conscious sedation revived interest in MUA-associated procedures. In fact, its use has expanded to include treatment for arthrofibrosis of the knee, chronic adhesive capsulitis (AC; i.e., frozen shoulder), and temporomandibular joint (TMJ) disorders, among other conditions. MUA is typically performed by orthopedic and osteopathic professional providers in an outpatient setting in a hospital or ambulatory surgical center, with the assistance of anesthesiologists as needed. MUA of TMJ disorders may be performed by oral maxillofacial surgeons.
ACUTE OR TRAUMATIC DISLOCATIONS OR FRACTURES
Joints are susceptible to traumatic injury, which can be typically classified as a dislocation, subluxation, or diastasis. Dislocations involve a complete disruption of a joint with a total loss of contact between the joint's articular surfaces. Subluxations involve joint malalignment, where some of the opposing joint surfaces remain intact. Diastasis is a separation or dislocation between two bones that are attached but have no true joint. The use of MUA is noted as an integral part of the restoration of a fractured or dislocated pelvic ring. MUA has not been established as a treatment option for pelvic subluxation or diastasis.
In the clinical community, MUA is an established treatment option for the closed (i.e., nonsurgical) reduction of displaced fractures, as well as acute or traumatic dislocations. Reduction is the positioning of a bone or bones to their normal position after a fracture or dislocation. Reduction is accomplished by applying traction at or across the fracture to relax and lengthen the muscles. Bone fragments are thereby manipulated back into position and are held using a cast or splint. Pressure may be applied to guide the bones into correct position (i.e., manipulation reduction). However, muscle spasm is often difficult to overcome without pain control (e.g., analgesia) and/or sedation. Although many fractures are reduced using sedation or regional anesthesia, individuals may be given general anesthesia to provide pain control and muscle relaxation.
PEER-REVIEWED LITERATURE
In a retrospective study, Betham et al. (2011) compared the effectiveness of procedural sedation in the emergency room with general sedation in the operating room for the manipulation of simple pediatric forearm fractures. Outcome measurements included time from presentation to fracture manipulation, procedure room occupancy, rate of remanipulation, and length of stay. Of the 385 patients presenting with forearm fracture, 108 underwent procedural sedation and 66 underwent MUA under general anesthesia. Time to manipulation was shorter in the procedural sedation group when compared with the general anesthesia group (58 ± 38 minutes vs. 558 ± 368 minutes, respectively; P<0.0001), as was the length of stay (139 ± 70 minutes vs. 1452 ± 544 minutes, respectively; P<0.0001). There was no statistically significant difference observed in rates of remanipulation between the two groups (P=0.305). The authors concluded that MUA under procedural sedation for the treatment of simple closed pediatric forearm fractures was associated with shorter delays to reduction and shorter length of stay when compared with traditional MUA under general anesthesia. The study is limited by its retrospective study design.
In a retrospective study, McKenna et al. (2012) evaluated the effectiveness of pediatric fractures manipulated with conscious sedation (e.g., nitrous oxide) versus pediatric fractures manipulated under a general anesthetic. Twenty-eight angulated or displaced nonphyseal forearm fractures were manipulated using conscious sedation, and 27 forearm fractures were manipulated under general anesthesia. The quality of reduction and cast index (how well the cast is molded to the contours of the forearm) were similar between the two groups. There was a statistically significant difference between the need for remanipulation among the children in the conscious sedation group when compared to the need for remanipulation among the children in the general anesthesia group. The authors concluded that despite a higher rate of failure, manipulation of fractures using conscious sedation can achieve an adequate reduction and a high quality of cast. They noted that failures were caused by inherently more unstable fracture personalities. The study is limited by its small sample size and the potential heterogeneity of baseline fracture personalities.
ADHESIVE CAPSULITIS (FROZEN SHOULDER)
The joint capsule of the shoulder has ligaments that hold the shoulder bones together. AC is a condition associated with loss of shoulder motion and pain. This condition is typically caused by the inflammation of the joint capsule, which prevents the shoulder bones from moving freely in the joint. AC occurs in about 2% to 5% of the general population and typically affects individuals between the ages of 40 and 60 years. It occurs more frequently in women than men.
Risk factors may include shoulder injury or surgery, cervical disk disease of the neck, diabetes, and hyperthyroidism. Idiopathic (i.e., resulting from no known cause) AC typically starts with pain, which prevents movement of the arm. This lack of movement may lead to stiffness, further decreased ROM, and persistent pain.
Conservative treatment typically includes nonsteroidal anti-inflammatory medications (NSAIDs) and steroid injections. Combined with physical therapy, ROM may improve in a few weeks, but may take as long as 6 to 9 months for complete recovery. Physical therapy is typically performed on a daily basis. Without treatment, AC can improve by itself within 3 years, with minimal loss of motion, if any.
Individuals who have had little or no improvement after 6 to 12 weeks of conservative treatment and have intractable, persistent pain may consider MUA, which involves humeral manipulation to disrupt adhesions. The procedure is not recommended in individuals who have had previous MUA with subsequent recurrence or in individuals with osteoporosis or significant osteopenia.
PEER-REVIEWED LITERATURE
In a retrospective study, Flannery et al. (2007) evaluated the influence of the timing of MUA for AC of the shoulder in 180 consecutive patients. Of these patients, 145 were available for follow-up after a mean of 62 months (12–125). All patients underwent MUA with intra-articular steroid injection. Statistically significant increases in ROM, function, and visual analogue score (VAS) were obtained. Ninety percent of these patients were satisfied with the procedure. Eighty-three percent of the patients had MUA performed less than 9 months from symptom onset, whereas the remainder had MUA performed after 9 to 40 months. The authors concluded that early intervention patients had a significantly better shoulder function score, although ROM and VAS pain scores did not indicate a statistically significant difference. The study is limited by its retrospective study design and lack of a comparative group control group.
In a retrospective study, Wang et al. (2007) evaluated the effectiveness of MUA for the treatment of idiopathic, posttrauma, and postsurgery AC. Fifty-one frozen shoulders in 47 patients were evaluated with an adjusted Constant score to assess shoulder function. The Constant score was determined pre-manipulation, at a 3-week follow-up, and at an average of 82-month follow-up. The adjusted pre-manipulation Constant score was a mean of 22.8 ± 4.9 (10–31). The score at 3-week follow-up was 52.6 ± 9.2 (31–67) and at a mean of 82 months was 70.1 ± 6.2 (54–75). Twenty-three shoulders scored for a maximum point number of 75 (25 points allocated for muscle strength assessment were excluded from the Constant score scaling). There was a statistically significant difference between the scores at the early and late follow-up end points in the postsurgery group when compared with the idiopathic and posttraumatic groups (P<0.001). The authors concluded that MUA is a noninvasive procedure that can shorten the course of a self-limiting disease, while improving shoulder function and symptoms within a short period of time. They did note that they found less improvement in postsurgery AC, especially with respect to residual pain and limited ROM. The study is limited by its retrospective study design and lack of a comparative control group.
In a prospective study, Ng et al. (2009) evaluated the effectiveness of MUA followed by physiotherapy in treating AC in 86 patients. Of these patients, 58.1% (n=50) completed follow-up. The average age of these patients was 54.5 years, and the mean duration of symptoms until MUA was 13 months. The mean VAS pain scores decreased from 6.07 to 1.88 (P<0.0005), flexion scores improved from 104.18 to 157.56 (P<0.0005), abduction scores improved from 70.48 to 150.00 (P<0.0005), and external rotation scores improved from 13.88 to 45.62 (P<0.0005). The authors concluded that MUA combined with physiotherapy alleviates pain and facilitates recovery for function in patients with AC. The study is limited by its small sample size, high loss to follow-up, and a lack of a comparative control group.
In a retrospective study, Sun et al. (2011) evaluated the effectiveness of MUA combined with arthroscopy for the treatment of primary AC in 34 patients. The average age of the patients was 56 ± 3.6 years [43–62], and the course of the disease had a mean time of 11.3 months (9–13). After concurrent arthroscopy and MUA was performed, all patients had postoperative rehabilitation and were followed for an average of 18.9 months (13–32). ROM and pain score outcomes were obtained. At 12-month follow-up, patients had a statistically significant decrease in pain (P<0.01) and an increase in their ROM (P<0.05). The authors concluded that MUA combined with arthroscopy is an effective and minimally invasive treatment for primary AC. The study is limited by its retrospective study design, small sample size, and lack of a comparative control group.
In a comparative study, Vastamäki et al. (2012) evaluated the natural history of idiopathic AC. Eighty-four shoulders in 83 patients, with a mean age of 53 years, were treated for a mean follow-up of 9 years (2–27). Fifty-one patients were untreated, 32 received nonoperative treatments (e.g., NSAIDs), and 20 underwent MUA. The mean age of MUA patients was 49 years, and the mean follow-up was 14 years (2–24). Outcome measurements included duration of disease, pain levels, and ROM. The duration of disease was an average of 15 months (4–36) in the untreated group and 20 months (6–60) in the nonoperative group. At last follow-up, ROM improved to 94% in the untreated group, 91% in the nonoperative group, and 91% in the MUA group. Fifty-one percent of patients in the untreated group, 44% in the nonoperative group, and 30% in the MUA group were completely pain-free at rest, during the night, and with exertion. The authors’ primary conclusions indicated that a high majority of patients with spontaneous AC recovered to normal levels of function without treatment. The study is limited by its retrospective study design, small sample size, and heterogeneity in comparison groups.
In a systematic review, Maund et al. (2012) evaluated the clinical effectiveness of treatments for primary AC. Thirty-one clinical effectiveness studies were included in their evaluation. In addition to MUA, steroid injection, sodium hyaluronate, supervised neglect, physical therapy, acupuncture, distention, and capsular release treatments were evaluated. Specific to MUA, the authors identified four randomized controlled trials (RCTs) for the treatment of primary AC. Each of these four RCTs had different comparison designs, which ranged from comparing the effectiveness of MUA to physical therapy alone to comparing the effectiveness of two different MUA techniques. The authors concluded that there was limited clinical evidence on the effectiveness of MUA for primary AC and that further high-quality research was required. The authors noted that these conclusions were because of the nature of its included and available studies, which primarily consisted of retrospective case series.
In a 2020 cohort study of thirty individuals, Kim et al. studied early clinical outcomes of MUA compared with 30 individuals with arthroscopic capsular release (ACR) among individuals
with refractory AC. The same professional provider
injected a steroid mixture into the shoulder capsule along with performing
internal and external rotations. The other group of individuals had an ACR performed with intra-articular steroid injection
performed upon surgery completion. Both groups received the same postoperative
rehabilitation protocol. Evaluation at 12 months showed that both groups
had significant improvement in ROM, but the MUA group
achieved restoration of ROM earlier in the postoperative period. The authors concluded
that MUA can be considered as a useful treatment option before pursuing ACR.
ARTHROFIBROSIS
Arthrofibrosis is a condition that can afflict joints that have been recently injured or received surgery. A traumatic stimulus leads the joint to form extensive, internal scar tissue, which is followed by shrinkage and tightening of the joint capsule. This tightening process may continue to the point where ROM is restricted, and afflicted individuals may lose the ability to straighten or bend the joints.
Conservative treatment for arthrofibrotic joints includes aggressive stretching, physical therapy exercises, and NSAIDS. For patients with refractory persistent and intractable pain, MUA is considered as a treatment option so that the restrictive, internal scar tissue is torn by forcing the joints to fully bend and straighten under anesthesia.
ELBOW
Peer-Reviewed Literature
In a retrospective study, Tan et al. (2006) evaluated the outcome of elbow release for the treatment of 52 patients with posttraumatic elbow stiffness. The mean age of the group was 35.1 years, and follow-up was a mean of 18.7 months. Specific to MUA, 27% of the patients (n=14) underwent closed manipulation in the early postoperative period. Complications to elbow release included wound infection (n=3), cubital tunnel syndrome (n=3), and reflex dystrophy (n=1). The authors concluded that the recurrence of elbow stiffness in the postoperative period is common, but MUA and repeat releases may be effective. The study is limited by its retrospective study design, small sample size, and lack of a comparative control group. Furthermore, due to the design of this study, the authors’ conclusions cannot be generalizable to patients undergoing MUA for the treatment of posttraumatic elbow stiffness.
In a retrospective study, Araghi et al. (2010) evaluated MUA for the treatment of 44 patients with limited articulation in the elbow. Follow-up occurred at a minimum of 12 months and revealed an improvement to 73º from a baseline arc of 33º. Three patients had no appreciable change (<10º) in the total arc, and one patient lost motion. Four patients underwent a second manipulation at a mean of 119 days after the first manipulation. Complications included worsening of the ulnar paresthesias in three patients, with two patients resolving their complications spontaneously, and one patient requiring anterior ulnar nerve transposition. The authors concluded that MUA for the elbow could be a valuable adjunctive procedure to help regain motion. However, they noted that additional studies should be conducted. The study is limited by its retrospective study design, small sample size, and lack of a comparative control group.
KNEE
Peer-Reviewed Literature
In a retrospective study, Keating et al. (2007) evaluated the effectiveness of MUA for patients who failed to achieve greater than 90º of flexion following total knee arthroplasty (TKA). A total of 113 knees in 90 patients underwent MUA and were followed at 6 months, and at 1, 3, and 5 years postoperatively. Ninety percent of the 90 patients (n=81) achieved improvement of knee flexion following MUA. The average flexion was 102º prior to TKA, 111º following skin closure, and 70º before MUA. The average improvement in flexion from the measurement made before MUA was 35º at 5-year follow-up (P<0.0001). There was no statistically significant difference in the mean improvement in flexion among patients who had MUA within 12 weeks postoperatively when compared with those who had MUA more than 12 weeks postoperatively. The authors concluded that MUA generally increases flexion following TKA and those patients with severe preoperative pain are more likely to require MUA. The study is limited by its retrospective study design, small sample size, and lack of a comparative control group.
In a retrospective study, Mohammed et al. (2009) evaluated the effectiveness of MUA for 21 patients with knee stiffness following partial or TKA. The average age of the patients was 62 years (56–80). The mean duration between knee arthroplasty was 13.2 weeks (6–32). ROM was analyzed pre- and post-MUA and at a subsequent follow-up. ROM improved from a mean of 60.2º [40–80] pre-MUA to 91.9º [45–120] post-MUA. The mean improvement was 31.6º (P<0.0001). At an average follow-up of 3 months (6 weeks–8 months), the mean arc of motion was 90.4º (40–120). The authors concluded that MUA has a role in the treatment of early stiffness following knee arthroplasty and results in immediate outcomes. The study is limited by its retrospective study design, small sample size, and lack of a comparative control group.
In a systematic review, Fitzsimmons et al. (2010) evaluated the outcome of three treatment modalities for arthrofibrosis that developed subsequent to a TKA. These treatment modalities included MUA, arthroscopy, and open arthrolysis. The authors included 14,421 studies, of which 23 were deemed relevant. ROM was the main outcome measurement. The gains in ROM after MUA and arthroscopy (with or without MUA) were similar, although open arthrolysis appeared to have inferior gains in ROM. The number of clinically important complications after MUA and arthroscopy (with or without MUA) were similar. The authors concluded that TKA can be improved with MUA and/or arthroscopy, with few complications. The study is limited by the included heterogeneous studies, which were retrospective in design.
In a systematic review, Ghani et al. (2012) evaluated the outcome of four main modalities of treatment for arthrofibrosis that developed subsequent to a TKA. These treatment modalities included MUA, arthroscopic debridement, open surgical release, and revision TKA. Twenty-five studies were selected, representing 798 patients. Two studies were prospective in design, while the remainder was retrospective in nature. The primary outcome measures assessed were ROM and knee scores. MUA had a mean increase of 38.4º, arthroscopic release had a mean increase of 36.2º, open surgical release had a mean increase of 43.4º, and revision TKA had a mean increase of 24.7º. Analysis indicated that there were no statistically significant differences between the four treatment modalities. The authors concluded that open surgical release would be the most beneficial option for patients who are fit to undergo secondary surgery subsequent to TKA. The study is limited by its included heterogeneous studies, which were mainly retrospective in design.
In 2022, Fackler et al. systematically reviewed the literature assessing the efficacy and complications of arthroscopic lysis of adhesions (LOA) and MUA for postoperative arthrofibrosis of the knee and evaluated whether any relevant subgroups are associated with different clinical presentations and outcomes. The included studies consisted of pre- and postoperative ROM measurements for the treated individuals, with the studies that reported outcomes for those with isolated cyclops lesions after anterior cruciate ligament reconstruction excluded. The studies showed a significant improvement in the arc of motion after arthroscopic LOA. Significant improvements in outcome measures, including the International Knee Documentation Committee, Western Ontario and McMaster Universities Osteoarthritis Index, and Knee Injury and Osteoarthritis Outcome Score were reported after arthroscopic LOA across all applicable studies. Of 240 individuals, a single complication (synovial fistula) occurred after LOA and MUA, which resolved without intervention. The limitations of the study included the nonrandomized nature of the included studies, which increases the risk of selection bias and confounding, and the lack of assessment of the publications for bias of outcomes of interest because less than 10 studies were synthesized for each outcome, and, lastly, significant heterogeneity for the study due to the wide range of definitions for arthrofibrosis. The authors concluded that a significant challenge continues to be knee arthrofibrosis postoperatively; however, when extensive nonoperative treatment fails, arthroscopic LOA and MUA may be a safe and efficacious treatment for arthrofibrosis in the postoperative knee.
In 2022, Grace et al. studied the impact of early MUA on cementless fixation by comparing functional outcomes and survivorship of cementless and cemented TKA through a multicenter study. A consecutive series of individuals who underwent MUA for postoperative stiffness within 90 days of primary unilateral TKA were found, and cases involving extensive hardware removal were excluded. TKAs undergoing MUA and cemented TKAs undergoing MUA were propensity-matched 1:1 using age, gender, body mass index, and year of surgery. At baseline, both groups had comparable baseline Knee Injury and Osteoarthritis Outcome Scores (KOOS), Short Form (SF)-12 physical, and SF-12 Mental scores. The study resulted in both groups showing MUA-related complications as equivalently low, with one patella component dissociation in the cementless group. In the perioperative period, no tibial or femoral components acutely loosened. The postoperative KOOS and SF-12 mental scores were similar between groups, demonstrating P=0.101 and P=0.380, respectively. There was a 98.0% 6-year survivorship free from any revision after MUA in both groups (P=1.000). The limitations of the study include the overall rate of aseptic loosening after TKA is low, which could demonstrate an underpowering of the difference in such aseptic loosening rates. Also, the study did not include the outcome variables that could further characterize how cementless TKA individuals do after early MUA. The authors concluded that in the early postoperative MUA after cementless TKA, there is no association with increased MUA-related complications or worse outcomes for individuals compared to cemented TKA. The SF survivorship remained comparable between groups, suggesting the bone implant interface's high durability. Future studies with the inclusion of additional variables in addition to a higher number of individuals would better characterize this population and could be particularly suited for implantation using robotic technology would be beneficial.
Haffar et al. in 2022 conducted a systematic review comparing outcomes of MUA, aLOA, and revision total knee arthroplasty (rTKA) for treatment of arthrofibrosis and stiffness after TKA. The primary endpoint was reported outcome measures and secondary outcomes were ROM and percentage of those who pursued further treatment for stiffness. There were 40 studies included in the review; 17 applied to MUA. For MUA, the authors noted some increase in ROM postoperatively. The authors also noted that all studies that reported preoperative and postoperative Knee Society Scoring (KSS) clinical and functional scores showed improvement at final follow-up following MUA. Additionally, only 17% of individuals who received MUA required further care. Limitations included poor quality of evidence for many studies included in this review.
CHRONIC SPINAL PAIN
Pain-related conditions involving the spine are typically treated over the course of several weeks with chiropractic care, physical therapy, or steroid injections. SMUA is a proposed treatment to manage persistent, intractable pain that is refractory to conservative treatment. After sedation is achieved, a series of mobilization, stretching, and traction procedures are performed on the spine and lower extremities. This may include passive stretching of the gluteal and hamstring muscles with straight-leg raises and hip capsule stretching. After the stretching and traction procedures, spinal manipulative therapy (SMT) is delivered with high-velocity, short-amplitude thrusts applied to the spinous process by hand, while the upper torso and lower extremities are stabilized. SMT may also be applied to the thoracolumbar or cervical area to address lower back pain.
SMUA typically takes 15 to 20 minutes and, after recovery from anesthesia, individuals are discharged with instructions to remain active, while using heat or ice for short-term analgesic control. Care after SMUA may include 4 to 8 weeks of active rehabilitation, which may involve additional SMT. SMUA has also been performed after injection of local anesthetic into the lumbar zygapophyseal and/or sacroiliac joints under fluoroscopic guidance and after epidural injection of corticosteroids.
PEER-REVIEWED LITERATURE
In a literature review, Kohlbeck and Haldeman (2002) indicate that there has been an increase in utilization of spinal manipulation as a method to treat select patients with spinal pain. The authors identified four categories of medication-assisted manipulation, including MUA under epidural anesthesia or sedation, under epidural anesthesia with or without epidural steroid injection, under joint anesthesia/analgesia, and with injections such as steroids or proliferant agents. The literature consisted primarily of case reports or series, two RCTs, and one cohort study. The authors concluded that despite a relatively long history of clinical use that spans over 70 years, the evidence to support the effectiveness of SMUA remains largely anecdotal. However, they noted that there was sufficient theoretical basis and positive results from some case series to warrant further controlled trials.
In a prospective comparative study, Palmieri and Smoyak (2002) evaluated the efficacy of using self-reported questionnaires to study MUA for 87 patients with chronic lower back pain. The intervention group consisted of 38 patients and the nonintervention group consisted of 49 patients. Patient selection was determined from a convenience sample. Outcome measurements included a numeric pain scale and a disability score. The average numeric pain scale scores in the MUA group decreased by 50% and the average disability scores decreased by 51%, while the nonintervention group had decreases of 26% and 38%, respectively. The authors concluded that self-reported outcomes improved after the procedure and that those patients in the MUA group had better improvements. They noted that larger scale studies were needed to support the effectiveness of SMUA for the treatment of chronic lower back pain. The study is limited by its small sample size and design, particularly as it utilized a convenience sample and its primary purpose was to evaluate the effectiveness of using self-reported questionnaires. Furthermore, there were no statistically significant or clinically meaningful differences between the MUA and nonintervention groups.
In a prospective cohort study, Kohlbeck et al. (2005) evaluated the effectiveness of MUA for the treatment of chronic lower back pain when compared to SMT alone. Sixty-eight patients with chronic lower back pain received an initial 4- to 6-week trial of SMT, after which 42 patients received supplemental MUA, while the remaining 26 patients continued with SMT. Outcome measurements included changes in pain and disability. At 3-month follow-up, lower back pain and disability scores favored the MUA group over the SMT-only group (mean difference of 4.4 points; 95% confidence interval [CI], −2.2–11.0). The difference attenuated at 1-year follow-up (mean difference of 0.3 points; 95% CI, −8.6–9.2). The relative odds of experiencing a 10-point improvement in pain and disability scores favored the MUA group at 3-month follow-up (odds ratio [OR], 4.1; 95% CI, 1.3–13.6) and at 1-year follow-up (1.9; 95% CI, 0.6–6.5). The authors concluded that MUA appears to offer some patients increased improvement in lower back pain and disability. They noted that further investigation of these benefits should be conducted in an RCT. The study is limited by its small sample size. Moreover, the results indicate that mean differences in lower back pain and disability scores are not statistically significant. In addition, from 3-month to 1-year follow-up, any discerned differences are attenuated and their statistical significance may be in question.
TEMPOROMANDIBULAR JOINT DISORDERS
The TMJ connects the temporal bone of the skull with the mandible (jaw) by an articulating condyloid process. The joint is cushioned by a layer of cartilage and by a disc that lies between the articulating surfaces. The disc adds stability and acts as a shock absorber. TMJ disorders typically arise from traumatic injuries, internal derangements, dislocations, ankylosis (joint stiffness due to abnormal adhesion), arthritis, neoplasms, and congenital and developmental abnormalities.
PEER-REVIEWED LITERATURE
In a prospective study, Foster et al. (2000) evaluated the effectiveness of MUA under general anesthesia for the treatment of TMJ disorder. Fifty-five patients were invited to participate in the study, with only 65% (n=36) participating. Of these, 15 patients improved, 15 did not, and six showed partial improvement. The median pretreatment opening of the mandible was 20 mm (13–27). Among those who improved after manipulation, the median posttreatment opening of the mandible was 38 mm (35–56). Some patients who improved posttreatment experienced a return of TMJ clicking, but not of joint or muscle tenderness. The authors concluded that MUA under general anesthesia may help some patients. The study is limited by its small sample size and short-term follow-up period. Poor study design may limit the generalizability of the results, which are hindered by low participation rates and primary outcome conclusions, which compared two distinct stratifications (median pretreatment opening of the entire cohort vs. median posttreatment opening of only patients who improved).
GUIDELINES
Initially in 2002 and updated again in 2015, the National Academy of Manipulation Under Anesthesia Physicians published guidelines to provide the recommendations for MUA. They indicated that MUA is clinically justified for individuals who respond favorably to conservative treatment for a 2- to 6-week period, but continue to experience intractable pain or biomechanical dysfunction. Diagnosed conditions must fall within recognized categories of conditions that are responsive to MUA. Serial MUA (more than one treatment session) was recommended when conservative care has been rendered, the injury is recurrent, and fibrotic tissue and articulator fixation prevents a single MUA session from being effective.
In 2002 and in a subsequent 2017 update, the International Chiropractors Association indicated that anesthesia is inappropriate and unnecessary to the delivery of a chiropractic adjustment.
In 2006, the American Chiropractic Association (ACA) indicated that MUA procedures are appropriate in a select patient population. In an ACA article, it was noted that MUA should be limited to individuals with specific neuromusculoskeletal conditions who have failed to respond to conservative management, are chronic and recurrent, cause disability that has been shown to respond to MUA, or have severe symptoms that could be temporarily relieved by MUA. In addition, the individual should be medically cleared for toleration to sedation. Noted adverse events include vascular, muscular, ligamentous, and osseous damage, anaphylaxis, respiratory and cardiac failure, coma, and death.
In 2008 and 2020, the American College of Occupational and Environmental Medicine (ACOEM) published guidelines that addressed the evaluation and management of common disorders among workers, including chronic lower back pain. They indicated that based on an insufficiency of evidence, SMUA was not recommended for the treatment of acute, subacute, or chronic low back pain because of the high potential for harm to the patient. With respect to knee disorders, the ACOEM recommended MUA for select postoperative patients with significantly reduced ROM because the intervention had limited potential for harm and constitutes best practices to treat and restore knee function. They did note that the current literature is too limited to support an evidence-based recommendation.
In 2016, the ACOEM, in a recommendation regarding MUA, concluded that MUA and medication-assisted spinal manipulation (MASM) are not recommended due to the lack of quality studies that solely evaluate MUA or MASM for treatment of acute, subacute, or chronic cervicothoracic and lower back pain.
SUMMARY
The evidence in the available published peer-reviewed literature indicates that MUA is safe and effective for a select patient population with specific indications, including the reduction of acute or traumatic dislocations and displaced fractures. When an individual has intractable, persistent pain refractory to conservative treatment (e.g., medical management, physical therapy), MUA may be indicated for individuals with arthrofibrosis of the knee following trauma or knee surgery (e.g., TKA) and AC of the shoulder.
There is a lack of adequate evidence in the published peer-reviewed literature and a lack of consensus among professional societies to support the effectiveness of SMUA for the treatment of spine-related chronic pain or MUA for the treatment of arthrofibrosis of any joint other than the knee (e.g., elbow). The available studies are limited in their design and small sample size. Specific to SMUA, many of the reported conclusions indicate that there were no statistically significant or clinically meaningful differences in pain or disability between SMUA and conservative treatment. Additionally, the most common serious adverse events associated with SMUA include disk herniation, cauda equine syndrome, and vertebrobasilar accidents, which may not resolve despite subsequent treatment.
There is limited evidence, if any, to support the effectiveness of MUA for the treatment of AC of any joint other than the shoulder (e.g., hip), TMJ disorders, or acute or chronic conditions related to, but not limited to, the ankle, elbow, finger, hip, toe, or wrist. Additionally, the use of MUA in treating multiple body joints or in serial treatment sessions has not been established due to the paucity of published peer-reviewed literature and a lack of consensus from professional society guidelines.
