Research Review By Dr. Kent Stuber©

Date Posted:

September 2009

Study Title:

Predicting short-term response to thrust and nonthrust manipulation and exercise in patients post ankle inversion sprain

Authors:

Whitman JM, Cleland JA, Mintken P et al.

Author's Affiliations:

School of Physical Therapy, Regis University, Denver, Colorado.

Publication Information:

Journal of Orthopaedic & Sports Physical Therapy 2009; 39(3): 188-200.

Background Information:

Inversion ankle sprains are common injuries that tend to heal well on their own, generally resolving with only residual symptoms after one month. Unfortunately these injuries have a nearly 80% recurrence rate. Further, depending on the activity level of the patient, it may be critical to speed this regular recovery interval.

According to some reports, these injuries are known to respond well to conservative treatments including manual therapy. Early active ankle mobility exercises are well studied and generally quite successful in the treatment and rehabilitation of inversion ankle sprains.

The authors contend that combining manual therapy and active ankle mobility exercises could have additional benefits to those who have encountered an acute ankle sprain. Thus they sought to develop a clinical prediction rule to identify those patients with inversion ankle sprains who might benefit the most from these combined interventions.

Pertinent Results:

75% of patients in the study had a successful outcome using the study protocol (see Study Methods below for definition of a successful outcome), 55% of those with treatment success had it at the time of their 2nd visit, with the remainder having success at their 3rd visit. There were no adverse events. Scores on the ankle specific functional and mobility outcome measures employed found that the group that had successful outcome from treatment had a significantly greater degree of improvement than the group that did not have success with the treatment, although this was not the case for pain scores.

Four variables were identified – if a patient had 3 of them in place the probability of successful outcome using those treatment methods was 95%.These variables were:
  1. Symptom worse with standing
  2. Symptoms worse in the evening
  3. Navicular drop greater than or equal to 5.0mm
  4. Distal tibiofibular joint hypomobility
The accuracy of the clinical prediction rule was highest with 3 of these factors were in place and lower with 2 variables (78% probability of success) or 4 variables (56% probability of success) present.

Clinical Application & Conclusions:

It is of great importance to formulate clinical prediction rules to arm clinicians with the knowledge of which patients are most likely to respond to certain treatments. This study provided the foundation for a potential clinical prediction rule for manual therapy and early general mobility exercises for ankle sprains indicating that if patients had at least 3 of the following 4 variables they have a 95% likelihood of success:
  1. Symptom worse with standing
  2. Symptoms worse in the evening
  3. Navicular drop greater than or equal to 5.0mm
  4. Distal tibiofibular joint hypomobility
If readers have patients with all 4 or 2 or fewer of these variables in place, it may be advisable to consider other treatment methods. Knowing the importance of the above mentioned variables is also of importance in directing items in the patient history (symptoms worse with standing or in the evening) and physical examination (using the navicular drop test and evaluating for distal tibiofibular joint hypomobility).

Study Methods:

85 consecutive patients were admitted to the study. Inclusion criteria included:
  • age 16-60 years
  • ankle pain consisting of a grade 1 or 2 ankle inversion sprain in the past year
  • pain rated at least 3/10
  • patients did not require x-rays as per the Ottawa Ankle Rules
Patients saw 1 of 9 physical therapists (at 1 of 4 different sites) who used a standardized (and extremely thorough) patient history and physical examination. Patients completed several baseline outcome measures including the Numerical Pain Rating Scale (NPRS), Foot and Ankle Ability Measure (FAAM), the Lower Extremity Functional Scale (LEFS), and the Beck anxiety index (BAI). These outcome measures were also completed at a final examination. Just before the second treatment session patients completed a Global Rating of Change (GROC) scale to see if they had clinically meaningful improvement (this occurred at the 3rd visit in necessary as well).

If patients were at least “quite a bit better” according to the GROC after the first treatment they were considered a treatment “success” and their participation in the study was complete. The rest had a second treatment session and then attended a follow-up visit where they completed a second GROC. If patients were again at least “quite a bit better” on the GROC their treatment was a “success” and the remaining patients were considered “nonsuccess” outcomes. 23 of the patients underwent a second clinical examination due to availability of a second examiner.

A standardized treatment was given in the first 2 sessions. There were 4 components to the treatment:
  1. Ankle/foot thrust (rearfoot distraction, proximal tib-fib posterior to anterior with a maximum of 2 attempts) and nonthrust manipulation (anterior to posterior talocrural, lateral glide/eversion rearfoot for 5x30-second bouts of grade III or IV joint manipulations)
  2. General mobility exercises (general ROM exercises including Achilles tendon stretching, alphabet exercises, and ankle eversion and dorsiflexion self mobilizations) - these were done in the clinic and were also to be done daily at home)
  3. Advice to maintain usual activity within pain limits
  4. Instruction regarding ice and elevation
Of note in the data analysis is that a significance level of P < 0.10 was employed (not the standard P < 0.05) for variables with the potential to be included as prediction variables.

Study Strengths / Weaknesses:

The methods of this study would be aided if a randomized controlled or randomized clinical trial design had been employed. As it stands the response to the treatment by the subjects cannot be strictly attributed to the treatment and the effects of simple natural history cannot be ruled out. It would be useful if the authors conducted a future RCT with a control group, a group that only received manual therapy, a group that only did exercises, and the combined therapy group to really determine which treatment(s) were most effective. However, as the intent of this study was to formulate a clinical prediction rule the methods were actually quite robust.

Additional concerns include the lack of long term follow-up, which is particularly important given the high recurrence rate of ankle sprains. It would be interesting to see if this intervention has any long term preventive effects that could aid in the prevention of recurrent ankle sprains or the development of chronic symptoms, but again an RCT would be preferable to ascertain this.

Most of the subjects had acute ankle sprains (only 16% had been injured for over 90 days) and thus it is difficult to determine how successful this treatment is for those with chronic injuries. The authors note the rather wide confidence interval surrounding the 95% success rate for patients with 3 out of 4 variables present and thus this success rate may not be completely accurate. The use of a significance level of P < 0.10 for including variables in the prediction rule may also reduce the validity of the rule.

The authors also comment on the navicular drop variable noting that a 7mm navicular drop is considered average, thus the 5mm drop in their variable is actually within a normal range.

One notable strength of this study is that reliability of the examination was assessed by having a second researchers examine the patient in 23 cases.

Additional References:

  1. Van Rijn RM, van Os AG, Bernsen RM, et al. What is the clinical course of acute ankle sprains? A systematic literature review. Am J Med 2008; 121(4): 324-331.e6.
  2. Kerkhoffs GM, Handoll HH, de Bie R, et al. Surgical versus conservative treatment for acute injuries of the lateral ligament complex of the ankle in adults. Cochrane Database Syst Rev 2007; Apr 18;(2): CD000380.
  3. Bleakley CM, McDonough SM, MacAuley DC. Some conservative strategies are effective when added to controlled mobilisation with external support after acute ankle sprain: a systematic review. Aust J Physiother 2008; 54(1): 7-20.