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Abstract
Aim To determine the outcome following fasciectomy for chronic exertional compartment syndrome (CECS) in the UK military, and the association between presurgical intramuscular pressure (IMP) and outcome.
Methods All patients who underwent fasciectomy for anterior CECS were identified between 2007 and 2010. Presurgery and postsurgery military medical grading for leg function was extracted from the medical records system. The Wilcoxon signed-rank test compared grades before and after surgery. Spearman's rank correlation examined the relationship between IMP and outcome.
Results Presurgery and postsurgery grading was available for 63% of patients. These patients had significantly better leg function after surgery (Z=−3.63, p<0.001). Of these, 49% improved by at least one grade, 36% showed no improvement in grading and 15% had a poorer outcome. There were no significant correlations between IMP and outcome.
Conclusions A large proportion of patients do not return to full fitness following fasciectomy in the military population. This is in line with a recent study in the US military, but conflicts with most civilian reports. The reasons for these differences are not clear. Furthermore, the lack of a relationship between IMP and outcome questions the role of pressure in this condition. These results suggest that the role of postoperative rehabilitation protocols and other conservative options should be explored.
- REHABILITATION MEDICINE
- SPORTS MEDICINE
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Key messages
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Only a minority of chronic exertional compartment syndrome patients returned to a fully fit medical category.
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This is the second military study to show poor prognosis.
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Presurgery intramuscular pressure is not associated with outcome.
Introduction
Chronic exertional compartment syndrome (CECS) usually affects the lower leg and is a restrictive condition causing pain during exercise that subsides with rest. The anterior compartment of the lower leg is affected most frequently.1 Diagnosis is generally made using intramuscular pressure (IMP) measurements at various time points before, during and after exercise. Criteria have been proposed pre-exercise,2 during exercise3 ,4 and 12 ,4 or 52 min postexercise.
Conservative management has historically been unsuccessful.5 Massage combined with specific stretching has been shown to increase time to pain onset.6 However, recent studies have suggested gait re-education may play a potential role in treatment of CECS.7 This is in line with two previous studies that have shown decreases in IMP due to a change in running style or in-shoe orthotics8 ,9 due to a theorised decrease in activation of tibialis anterior.
Where conservative measures have failed, surgical intervention with either fasciotomy (longitudinal division of the compartment fascia) or fasciectomy (longitudinal division and excision of 1 cm strip of fascia) is used. It is hypothesised that these procedures reduce the pressure and therefore pain when exercising. Fasciectomy is thought to reduce recurrence by preventing scar tissue forming between the split fascial ends.10
Outcomes following surgery have been reported but often in self-reported studies. These studies have suggested good short-term outcomes. A rare study of long-term outcomes10 showed that 13 of 62 subjects still reported substantial pain in the long term or required repeated surgery. Although 60% of patients who underwent only primary surgery (n=50) reported an excellent or good outcome, 58% of all patients (n=60) were exercising at a lower level than before their injury, of which 36% reported that this was due to either recurrence of their compartment syndrome or symptoms in a different compartment. More recently, Waterman et al11 reported the largest outcome study to date of 611 US military patients with most having fasciotomy of the anterior and lateral compartments. By contrast with other civilian studies, this found that almost 45% of patients had recurrence of symptoms.
We carried out a service evaluation to determine the outcomes of UK military personnel treated for CECS by fasciectomy that had had previous IMP testing of the anterior compartment of the lower leg. A secondary aim was to determine the effect of presurgical IMP on outcome following surgery with a null hypothesies that surgery and presurgical IMP would have no effect on outcome.
Methods
All patients who underwent fasciectomy for lower leg anterior CECS were identified between 2007 and 2010 at a single rehabilitation facility. Surgery was performed by two surgeons who decompressed the anterior compartment at primary surgery, with an additional incision for those who also had posterior involvement.
Operative technique
Patients were placed supine and given preoperative antibiotics (flucloxacillin 1 g or Teicoplanin 600 mg plus gentamicin 120 mg). A pneumatic thigh tourniquet was inflated to 300 mm Hg, the skin prepared with alcoholic chlorhexidine (2%) and the leg draped. The anterolateral border of the tibia was marked and a longitudinal incision made 1–2 cm lateral to this line. The skin incision is made long enough to ensure that the fascia can be divided along its entire length. After division of the fascia of the anterior compartment longitudinally, a 1 cm strip was removed from the lateral edge.
After meticulous haemostasis, the wound was closed in layers with an absorbable deep dermal and then subcuticular suture. The wound is then dressed and wrapped with wool and crepe bandage and the wound kept dry for 1 week prior to a wound inspection. Rehabilitation under the physiotherapist began immediately and was reviewed 6 weeks postoperatively before being discharged to the care of the rehabilitation team.
A presurgery and postsurgery (most recent) military medical grading for locomotion (L grade: PULHHEEMS assessment)12 was extracted manually from the medical records system. The L grade (Table 1) indicates an individual's ability to march/run with higher grades indicating greater limitations in locomotion ability and physical duties permitted. In addition to limb-specific outcomes, overall functional outcome is determined by the ability of the patient to return to military duty. Based on standardised military employment criteria, patients were assigned into four employment categories (fully fit, limited employability, sedentary duties only and unfit for military duty). To be fully fit, they must be able to pass standardised fitness tests involving running (2.4 km in a set time limit) and marching with weight (8 miles with up to 25 kg pack).
Functional Interpretation of L Grade
The IMP tests of these patients were reviewed. IMP was measured bilaterally before, during and up to 5 min after exercise. Pre-exercise and postexercise pressures were measured with the patient in a relaxed supine position. A fluid-filled slit catheter connected to a pressure transducer was inserted into the tibialis anterior muscle at an angle of 30°. This was connected to a computer and the data recorded. Exercise was continued until patients stopped due to pain. The start and end of exercise was determined visually from the pressure trace. A slit catheter with occasional flushing of the test system is considered suitable for continuous pressure testing.13 The flushing does, however, require the patient to stop exercising momentarily on occasion during the test. These periods were noted and excluded from further calculations. Of the fluid-filled devices, the slit catheter is considered one of the most accurate.14 The time that the patient was supine was also noted where this had been annotated.
Patients were considered for fasciectomy if they had a history consistent with CECS, had failed conservative measures and had an IMP consistent with the diagnosis. Only patients who underwent fasciectomy for anterior CECS by one of two surgeons were included in this study. Patients were not excluded if they also had symptoms/surgery in other compartments. Patients having primary surgery (and a subsequent revision surgery where necessary) were included. However, patients with only revision surgeries during the time period were excluded. Patients were also excluded if they did not have an IMP test of the anterior compartment of the lower leg prior to surgery.
Data processing and analysis
Raw data from the IMP tests was processed in Scilab V.5.3.2. The Wilcoxon signed-rank test compared outcome before and after surgery. Spearman's rank correlation was used to examine the relationship between IMP and outcome. Prior to analysis, the data was checked to confirm it met the assumptions of the proposed tests. All data analyses were undertaken in SPSS V.17.0. All means are presented as mean (sd) unless otherwise stated.
A second analysis was undertaken to check for bias due to catheter occlusion that typically reduces frequency response. All 3 s periods during exercise (to ensure at least one contraction-relaxation cycle had been completed), where the range of pressures was less than 50 mm Hg were excluded.
Results
Ninety-eight new patients (189 legs) were operated on during this time period, with eight patients (15 legs) having further revision surgery (8%). Revision surgery occurred at an average of 64 (41) weeks after the first operation (range: 9–119 weeks). In the group having primary surgery, 90% were male. The mean age was 28 (6) years.
During IMP testing, the mean duration of exercise before discontinuing due to pain was 540 s (272). An additional 40 s (25) was required from the end of exercise to the supine position. The mean pressures during and after exercise are presented in Table 2. IMP did not correlate with outcomes regardless of the time points used with no coefficients greater than 0.21.
Mean IMP (SD) during and after exercise
Almost all fasciectomies were bilateral (93%) with six patients also having posterior involvement. There were 6 (6%) reported complications after surgery other than recurrence of symptoms (four wound infections including one patient who needed admission, and two seromas).
Before surgery, 16% of patients were classed as L2 (fully fit), 37% L3 (limited employability) and 47% L7 (sedentary duties only). After surgery, 42% were classed as L2, 39% L3, 18% L7 and 2% L8 (unfit for military duty). This data was extracted 23 (9) months postsurgery. Presurgery and postsurgery medical gradings were available for 63% of patients. A significantly higher proportion of patients improved leg function (L grade) than regressed after surgery (Z=−3.63, p<0.001). Of these patients, 52% improved, 37% showed no improvement, and 11% deteriorated.
Discussion
This is one of the largest case series reported for this condition, and shows a statistically significant greater number of patients improve their medical grading than regress. However, 48% showed either no improvement or worsening of lower limb function using an occupational outcome measure. Importantly, less than 45% were graded as fully fit (L2) 2 years after surgery. Additionally, no correlation between IMP and outcome could be shown.
Administrative error meant that 10 patients were reported in the medical records system to be fully fit prior to surgery which is not in line with their requirement for surgery; we were unable to ascertain the true grading for these patients. Excluding these patients did not significantly alter the outcomes
In a military context, the purpose of this operation is to return personnel back to full duties. These results demonstrate that surgery carries risks of complications and does not reliably return patients to full fitness. Previous studies with athletic populations often report ‘return to full activity’, although the level of activity actually achieved is often unknown. However, these findings are more consistent with Waterman et al11 who report symptom recurrence in 45% of patients.
Detmer et al15 report that 73% of all involved compartments (40% were anterior) were completely cured of their symptoms after fasciotomy, whereas Howard et al16 report a mean improvement in pain scores of 68% where 85% of compartments were anterior. In a study of 16 patients, Schepsis et al17 stated that 4 years after surgery, all patients could return to full activity and could run an unlimited amount with no recurrence of symptoms; although they then go on to report that one patient had only slightly improved, and 96% of anterior compartment patients had excellent results. The same group then report further results in a second paper of which less than 50% were classed as ‘excellent’.18
In comparison, less than 45% of our patients were classified as fully fit (L2) after surgery. Data from Styf and Korner19 also suggests that surgery had unpredictable outcomes. They reported that physical activity was unlimited in only 5/19 patients 8 months after fasciotomy and in 6/19 patients after 25 months.
Most studies report the use of fasciotomy as a first-line procedure,20 However, the only study comparing fasciotomy and fasciectomy demonstrated lower complications and fewer recurrences with fasciectomy.21 We, therefore, do not feel that we should attribute our results to this slight difference in technique.
The reasons for the apparent discrepancy between military and civilian outcomes are unknown although various theories for this discrepancy have been made.22 For example, military personnel may have different physical demands than civilian athletes. It must be noted that none of these papers performed functional testing or lower limb scoring of their patients before or after treatment. Therefore, direct comparisons cannot be made. Nonetheless, our finding, in combination with that of the US military, warrants further investigation into these reasons and into alternatives to surgery. The impact of postoperative rehabilitation protocols must also be examined.
Greater IMP at all time points was not associated with improved surgical outcomes. This echoes the results of Gershuni et al23 and Detmer et al,15 although contrasts with a more recent study24 which focused on the deep posterior compartment. This finding further questions the role of intracompartmental pressure in this condition. We used IMP testing to aid diagnosis as it was the best available test at the time. However, two systematic reviews have since identified methodological flaws in the formation of the diagnostic criteria.25 ,26 If the aetiology of CECS is higher compartmental pressure, IMP should be expected to be associated with outcome. The lack of association in this study, further undermines our current understanding of this condition.
The main technical problems with fluid-filled testing systems are due to catheter occlusion. This can lead to a drop in the frequency response which could lead to erroneous results. This phenomenon was seen in several tests and often led to flushing of the system. We found that the filtering of test periods that exhibited signs of catheter occlusion did not affect the statistical significance. A detailed discussion of dynamic pressure measurement within our military population has already been reported along with the description of a subset of data.27
Similar to Waterman et al,11 this study is limited by its retrospective evaluation of prospectively collected data and reliance on the medical record. However, in this study, the surgical technique is better controlled with only two surgeons at a single centre compared to 32 different centres. Waterman et al's study excluded more than a quarter of medical records. We were similarly restricted by the availability of premedical and postmedical gradings. The reasons for this are unclear, and could be a source of bias in the results.
This series is the second to show relatively poor occupational prognosis after surgery for CECS in a population which requires a high level of functional ability. Although demonstrating that patients generally improve lower limb function following surgery, only a minority returned to a fully fit medical category. We suggest that our results demonstrate the true efficacy of surgery when trying to return individuals back to activities requiring high levels of function and load-carrying abilities.
The reported poor outcomes following surgery have led us to develop new conservative methods to treat military personnel with exertional leg pain, however, the evidence for this approach is currently lacking. The biomechanical factors that may influence IMP are currently a subject of ongoing research and may ultimately reduce the number of cases referred for surgery and target those who will benefit most from it. Validated outcome tools that can measure these changes are also needed for this condition.
References
Footnotes
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Contributors AJR planned the whole study, collated the pressure data, analysed the data, drafted and revised the paper and is the overall guarantor. JMQ collected outcome data and revised the paper. PK helped plan the study, collected outcome data and revised the paper. JH helped plan the study and revised the paper.
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Competing interests None.
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Funding The work was sponsored by the Ministry of Defence as part of the authors' employment.
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Ethics approval This study was approved by the local DMRC service evaluation committee.
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Provenance and peer review Not commissioned; externally peer reviewed.