Abstract
Objectives
To compare the effects of initiating physical therapy (PT) immediately versus resting before starting PT on pain and dysfunction over 12 months in adolescent athletes (10–19 years) with active lumbar spondylolysis.
Methods
This prospective multicentre trial randomised participants to immediate PT or rest before PT. The immediate PT group began PT within 7 days and progressed based on pain and function. The rest before PT group started PT once symptoms resolved and progressed based on time. The primary outcome was pain and disability (Micheli Functional Scale) between groups over time, measured at baseline, 1 (primary end point), 3 and 12 months. Time to return to sport and the recurrence rate of low back pain (LBP) were also assessed. Outcomes were analysed using an intention-to-treat approach.
Results
Sixty-four participants (median age 14.2 years; 40% female) were randomised to immediate PT (n=30) and rest before PT (n=34). At 1 month, the immediate PT group showed significant improvements in pain and disability (mean difference on Micheli Functional Scale of 21.3, 95% CI 28.7 to 13.9; p<0.001). They also returned to sport 38 days sooner (p<0.001), with fewer recurrences of LBP over 12 months (3% vs 29%; p=0.01). There were no adverse events.
Conclusions
Clinicians may consider prescribing PT immediately after diagnosing active lumbar spondylolysis instead of rest. Immediate PT showed greater initial improvements in pain and dysfunction, a quicker return to sport and a lower recurrence of LBP compared with rest before PT among adolescent athletes with spondylolysis.
Trial registration number
Keywords: adolescent, athletes, spine
WHAT IS ALREADY KNOWN ON THIS TOPIC
Lumbar spondylolysis is common among adolescent athletes with low back pain (LBP).
The standard treatment for lumbar spondylolysis varies due to the lack of controlled trials.
WHAT THIS STUDY ADDS
Starting physical therapy immediately after a lumbar spondylolysis diagnosis in adolescent athletes is more effective than prescribing rest, as it reduces recovery time to return to sport and results in fewer recurrences of LBP.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
The implications of this study could alter the standard treatment for lumbar spondylolysis, by highlighting the benefits of immediate physical therapy over prescribed rest.
Introduction
Spondylolysis, a bone stress injury in the lumbar spine, is the most common identifiable cause of low back pain (LBP) in young athletes, with a prevalence of 14%–30%.1,4 Spondylolysis can lead to severe LBP and dysfunction during activity and sports. To manage pain, disability and promote bone healing, a typical treatment approach for young athletes involves prolonged rest from physical activity and sports before starting physical therapy (PT).5,8 However, only limited low-level evidence has assessed the effectiveness of prolonged rest for spondylolysis, and the outcomes of this treatment approach prompt us to reconsider its use.69,11 With care involving prolonged rest, most young athletes return to their sport in roughly 4–7 months, a duration that patients and families often find distressingly long.5,8 Although rest is prescribed to promote bony healing of spondylolysis,12 13 only 68%–82% of these injuries achieve bony healing.5 14 Furthermore, prolonged rest from activity may lead to atrophy of spinal muscles, weight gain, fear of movement and depression,15,17 all predictors of chronic LBP.18 19 In addition, long-term outcomes are concerning: 42%–45% of young athletes experience chronic or recurrent LBP within 1–8 years after injury, with 37% seeking more medical care for LBP and 18%–21% reducing physical activity specifically due to LBP.10 11 These outcomes and negative consequences raise questions about the necessity and benefits of prolonged rest before starting PT when treating lumbar spondylolysis in young athletes. Preliminary evidence suggests that early PT may reduce time to recovery in this population.9 20
The purpose of this study is to compare the effects of initiating PT immediately versus resting before starting PT on pain and dysfunction over 12 months in adolescent athletes (10–19 years) with active lumbar spondylolysis. Based on preliminary studies,9 20 we hypothesised that athletes with active spondylolysis who started PT right away would experience faster improvements in pain and dysfunction, return to sport sooner and have fewer recurrences of LBP compared with athletes who rest before starting PT.
Methods
Study design
This study was a prospective, multicentre, two-arm, parallel, randomised controlled trial. Participants were evaluated at baseline, 1, 3 and 12 months after enrolment. This report follows the Consolidated Standards of Reporting Trials extension for non-pharmacological treatments guideline and the Template for Intervention Description and Replication checklist for intervention description.21 22 This study was prospectively registered at www.ClinicalTrials.gov on 22 August 2022 (identifier number NCT05505981) (online supplemental file 1) .
Participants
Participants were recruited from September 2022 to June 2024 from the sports medicine departments of two paediatric hospitals in the USA: Nationwide Children’s Hospital (NCH) in Columbus, Ohio and Children’s Hospital Colorado (CHCO) in Aurora, Colorado. Patients were not directly involved in the design, conduct or reporting of this trial.
Adolescents (aged 10–19 years) were eligible if they met the following inclusion criteria: (1) diagnosed with active spondylolysis using MRI. Active spondylolysis was defined as oedema in the posterior elements of the lumbar vertebrae at the pars interarticularis with or without a fracture and (2) participation in organised sports at least twice per week at the time of diagnosis or onset of LBP. The exclusion criteria included (1) previously rested from activity for >4 weeks due to LBP; (2) reported numbness or tingling in any lumbar dermatome; (3) previous lumbar spine surgery or (4) a prior injury or condition that affected the plan of care for spondylolysis (eg, pregnancy, ACL tear in the knee or concussion).
Interventions
Following enrolment, participants were randomised into one of two treatment groups: the immediate PT group and the rest before PT group. Group assignment determined when participants started PT and how they progressed through the programme. Participants in both groups rested from all sports activities, were not braced and received personalised PT for two 1-hour sessions per week until they met the return-to-sport criteria. Licensed physical therapists specialising in treating youth athletes and trained in the protocols provided PT for both groups. Treatment fidelity and adherence was monitored through chart review and rated on a 0–9 scale (0–3=low, 4–6=moderate and 7–9=high) (online supplemental 2.3).
Immediate PT group (online supplemental 2.1): participants in the immediate PT group began PT within 1 week of diagnosis and followed the immediate functional progression programme20 (figure 1). This programme is a structured, three-phase rehabilitation plan that allows adolescent athletes with active spondylolysis to begin exercise immediately without exacerbating symptoms. Progression through the phases is based on meeting specific function and pain criteria.
Figure 1. Physical therapy (PT) treatment progression programmes.
Rest Before PT group (online supplemental 2.2): participants in the rest before PT group rested, performing no physical activity or exercise beyond activities of daily living, until their lumbar pain resolved for two consecutive days. They contacted the study staff once their symptoms resolved, and PT began within 1 week. Participants in the rest before PT group followed the same PT treatment programme, progressing based on a set timeline since their pain had already resolved (figure 1).
Return-to-sport criteria: athletes in both groups were cleared to return to sport and discharged from care after completing their PT protocol and meeting the following criteria:
Pain-free repetitive motion to end-range in all cardinal lumbar directions.
Completion of 2 weeks of return-to-sport activity in PT without pain.
No reported pain or disability (0% score on the Micheli Functional Scale (MFS)).
Outcomes
All patient-reported measures were entered into Research Electronic Data Capture (REDCap), an electronic data capture tool,23 24 at baseline, 1 (primary end point), 3 and 12 months.
Pain and function (primary outcome): changes in participants’ pain and function over time were assessed using the MFS, a self-report measure specifically designed for adolescent athletes with LBP. The MFS measures pain and functional ability on a scale from 0 to 100, where 0 indicates no pain or disability and 100 indicates the maximum. The MFS has demonstrated validity (α=0.90) and reliability (α=0.79 and 0.90) for this population,25 26 whereas other common measures for LBP, such as the Oswestry Disability Index, have limited applicability in this population.27,29
Secondary outcomes
Time out of sport: the number of days from the diagnosis of spondylolysis, when they were removed from sport, until participants met the return-to-sport criteria.
Significant recurrence of LBP (yes/no): any participant who received medical treatment for LBP after discharge during the 12-month follow-up was regarded as having experienced a significant recurrence of LBP.
Healing on MRI: participants underwent MRI of the lumbar spine at baseline for diagnosis and at 3 months. The image acquisition consisted of sagittal and axial T1-weighted and T2-weighted spin echo sequences, followed by Sagittal Fast Spin Echo Inversion Recovery and a Sagittal 3D Multiple Echo Recombined Gradient Echo. A single paediatric spine radiologist, blinded to group allocation, analysed all images. The radiologist compared changes in the lesion and oedema between baseline and 3-month MRIs to determine whether the lesion was healing, showed no change or had worsened.
Patient-reported outcome measures: questionnaires evaluated the intervention effects on participants’ depressive symptoms, fear of movement and quality of life. Depressive symptoms were measured with the Patient-Reported Outcomes Measurement Information System paediatric depressive symptoms short form. Fear of movement was evaluated using Fear Avoidance Beliefs Questionnaire-physical activity subscale. Quality of life was assessed with Paediatric Quality of Life Inventory.
Atrophy of lumbar multifidus muscle: changes in the functional cross-sectional area (total cross-sectional area minus fatty infiltrate) of the lumbar multifidus muscles were analysed using MRI (baseline to 3 months) at the L4/L5 level to assess atrophy. The cross-sectional area and fatty infiltrate were measured using OsiriX software.30,32
Randomisation and blinding
An independent statistician created a computer-generated block randomisation list. The block randomisation ensured an approximately 1:1 allocation ratio between the immediate PT and rest before PT groups at each hospital. The randomisation list was uploaded to REDCap, which enabled concealed allocation and ensured participants were randomised only after providing consent and completing the baseline questionnaire. Due to the nature of the interventions, participants and treating clinicians were not blinded; however, the radiologist reading the MRIs and assessing healing was blinded.
Sample size estimation
Sample size estimates based on previous research were calculated beforehand using anticipated differences necessary to detect clinically meaningful change on the MFS. A sample size of 60 participants (with recruitment continuing until a minimum of 30 per group was obtained) was considered sufficient to detect a clinically meaningful difference of 20 units at any time point with 80% power, a two-sided alpha level of 0.05 and a group SD of 21.2, assuming a 10% dropout rate.20 25 33
Data analysis
Summary statistics were calculated using medians (IQR) for continuous variables, and n (%) for categorical variables, to assess baseline between-group balance after randomisation. Linear mixed-effects models with random intercepts and slopes, time as a categorical variable and an unstructured covariance matrix using restricted maximum likelihood were fit for the primary outcome of interest. For the MFS (primary outcome), the group-by-time interaction was analysed for difference between groups over time with an intention-to-treat approach. Model assumptions of normality and homogeneity of variance were visually assessed and satisfied. Post hoc analyses of each individual time point were also conducted to determine if any met our criteria for a clinically significant difference of 20 points, with 1 month (primary end point) hypothesised as having the largest between-group difference. Time until return to sport from diagnosis was analysed with a Kaplan-Meier curve and log-rank test, with diagnosis as the start and return to sport as the end. All patients returned to sport, so no censoring was necessary. Ninety-five per cent CIs were constructed for Kaplan-Meier median return-to-sport times using 1000 bootstraps. Fisher’s exact test compared recurrence of LBP between groups. Additional patient-reported outcomes in online supplemental 2.3 are shown with means (95% CI) at each time point and were not model-based. All p values and 95% CIs are reported at nominal levels, and all analyses were performed in R V.4.4 and Stata V.18.0.
Equity, diversity and inclusion statement
The study included adolescents with lumbar spondylolysis referred from primary care sports medicine physicians. The study population included participants from a broad range of ethnic/racial and socioeconomic backgrounds. The author team included one junior scholar (woman), four senior clinician/academics (one man and three women) and two senior academics (one woman, one man).
Results
Sixty-four adolescent athletes with active spondylolysis enrolled in the study from two hospital systems (NCH=48, CHCO=16). Participants were randomised into one of two treatment groups (immediate PT=30, rest before PT n=34) (figure 2). Baseline demographics are presented in table 1. Participants in the immediate PT group started PT 6 (IQR 4, 7) days from spondylolysis diagnosis, and participants in the rest before PT group started PT 28 (IQR 21, 39) days following diagnosis. Treatment fidelity and adherence was high overall online supplemental 2.3, with a median score of 9 out of 9 (immediate PT=9/9, Rest before PT 9/9), scores ranged from moderate (5/9) to high (9/9). The treatment fidelity and adherence to the assigned interventions was considered high in 92% of participants.
Figure 2. Participant flow diagram. CHCO, Columbus, Ohio and Children’s Hospital Colorado; CONSORT, Consolidated Standards of Reporting Trials; NCH, Nationwide Children’s Hospital.
Table 1. Participant demographics at baseline.
| Variable | Patients (n=64) |
Immediate PT group (n=30) |
Rest before PT group (n=34) |
|---|---|---|---|
| Age (years) | 14 (13, 15) | 14 (13, 15) | 14 (13, 15) |
| Sex (% female) | 21 (40%) | 9 (36%) | 12 (43%) |
| BMI (kg/m2) | 21.3 (19.6, 24.0) | 21.1 (20.3, 25.7) | 21.5 (19.5, 23.9) |
| Duration of symptoms before initial evaluation (weeks) | 7 (4.5, 12) | 7 (4, 12) | 6.5 (5, 12) |
| Spondylolysis at L5 | 45 (70%) | 21 (70%) | 24 (71%) |
| Type of lesion (bilateral) | 40 (62%) | 22 (73%) | 18 (53%) |
| Stage of lesion (lysis) | 44 (69%) | 23 (77%) | 21 (61%) |
Data are medians (IQR) or numbers (%).
BMI, body mass index; PT, physical therapy.
Primary outcomes
The MFS of participants randomised to the immediate PT group was significantly better than those in the rest before PT group over time (p<0.001). Post hoc testing revealed a significant difference between groups on the MFS at 1 month, exceeding our predefined clinically meaningful difference of >20 points at any time point. Immediate PT scored 21.3 points (95% CI –28.7 to –13.9) lower than rest before PT participants at 1 month (p<0.001) (figure 3, table 2).
Table 2. Micheli Functional Scale differences over time.
| Micheli Functional Scale time point* | Rest before PT group (n=34) | Immediate PT group (n=30) | Difference between groups† |
|---|---|---|---|
| Baseline | 52 (46, 57) | 47 (41, 53) | −5 (−3 to 12) |
| 1 Month‡ | 37 (31, 43) | 15 (8, 22) | −21 (−30 to –12) |
| 3 Months | 10 (5, 14) | 5 (0, 9) | −5 (−11 to 1) |
| 12 Months | 7 (4, 11) | 5 (1, 9) | −2 (−8 to 3) |
Missing data: none missing at baseline; two missing in each group at 1 month; one missing in rest before PT group at 3 months; three missing in rest before PT group and four missing in immediate PT group at 12 months.
Presented as mean (95% CI) based on a linear mixed-effects model that includes terms for treatment group and categorical time, as well as their interaction. A random intercept for each individual and random effects for time as a categorical variable were incorporated.
Primary end point of interest.
PT, physical therapy.
Figure 3. Change in pain and function over time. Group means and 95% CIs are shown. PT, physical therapy.
Secondary outcomes
Participants assigned to the immediate PT group met the return-to-sport criteria 38 days sooner than those in the rest before PT group (95% CI 17 to 50; p<0.001). The immediate PT group met the return-to-sport criteria after a median of 74 days (95% CI 64 to 85), whereas the rest before PT group did so at a median of 112 days (95% CI 92 to 132) (figure 4). Participants in the immediate PT group experienced fewer recurrences of LBP during the 12-month follow-up period, with one (3%) participant in the immediate PT group and 10 athletes (29%) in the rest before PT group seeking further medical treatment (p=0.01).
Figure 4. Kaplan-Meier plot for time to return to sport from injury. PT, physical therapy.
Imaging—of the 64 enrolled athletes, 53 (83%) obtained their 3-month MRI (immediate PT group=25, rest before PT group=28). By 3 months, 41 (77%) of all imaged participants demonstrated significant healing on MRI (immediate PT=84%, rest before PT=71%), five (9%) demonstrated no change (immediate PT=8%, rest before PT=10%) and seven (13%) had worsened (immediate PT=8%, rest before PT=18%). Bony healing on MRI demonstrated no significant differences between groups (p=0.30). However, the difference in multifidus muscle functional cross-sectional area between groups was significant. Although there is no established clinically meaningful difference for functional cross-sectional area, we found that the combined functional cross-sectional area of the multifidi increased by 7.0% (1.5 cm2) in the immediate PT group, whereas the rest before PT group demonstrated a slight 1.4% decrease (0.20 cm2), resulting in a between-group difference of 1.7 cm2 (95% CI 0.2 to 3.2; p=0.03). Half of the participants (50%) in the rest before PT group and 20% in the immediate PT group had multifidus atrophy.
Depression, fear of movement, quality of life
Overall, participants in both groups reported low levels of depressive symptoms, with no significant difference between groups (online supplemental 2.4). The assigned treatment group did not significantly affect fear-avoidance beliefs. Participants in the immediate PT group had slightly lower PedsQL scores at baseline, and they remained lower throughout, with the assigned treatment group having no effect.
Discussion
This prospective trial is the first to evaluate the impact of prescribing immediate PT instead of rest for adolescents with active lumbar spondylolysis. The results of this multicentre randomised controlled trial support our hypothesis that adolescent athletes with lumbar spondylolysis who begin PT immediately have greater initial improvement in pain and dysfunction. At 1 month, participants in the immediate PT group had clinically and statistically significantly better pain and function on the MFS compared with rest before PT. At 3 and 12 months, both groups had achieved similarly low MFS scores. Additionally, patients who begin PT immediately return to sports sooner and have fewer recurrences of LBP compared with injured athletes who rested before starting PT. Participants in the immediate PT group started PT a median of 21 days earlier and returned to sport 38 days sooner than those in the rest before PT group, despite completing a similar number of PT sessions. Additionally, the recurrence of LBP after treatment was significantly lower with immediate PT compared with those who rested. Finally, there were no reportable adverse events and no differences in spondylolysis healing on the 3-month MRI, suggesting that starting PT immediately does not impair healing potential.
Young athletes with lumbar spondylolysis want to return to sports quickly. However, their desire to return swiftly to their sport must be balanced with their long-term health.34 This study found that starting PT immediately helps participants to recover from lumbar spondylolysis, allowing a full return to sport without pain or dysfunction after a median of 2.5 months, without compromising long-term outcomes. This recovery timeline is significantly shorter than earlier studies of 4–7 months for adolescent athletes with spondylolysis.5,8 Ultimately, 94% of participants in both groups and 100% of participants who adhered to the study protocol made a full return to sport, aligning with previous conservative care findings.35 36
Our results indicate that starting PT immediately may improve outcomes in adolescents with lumbar spondylolysis over 12 months. Prior research in this population demonstrated a high recurrence of LBP—with 37% seeking care—when rest was prescribed.11 In this study, the rest before PT group saw a similarly high recurrence rate of 27%, while the immediate PT group had a recurrence rate of only 3%. We theorise the lower recurrence rate in the immediate PT group may be due to less disuse and muscle atrophy compared with the rest before PT group, which are linked with chronic or recurrent LBP.18 19
This study assessed the healing of spondylolysis stress injuries by investigating changes on follow-up MRI to ensure that immediate PT did not compromise healing. We found that initiating PT immediately did not significantly impede bony healing potential as seen by worsening oedema and/or fracture line on MRI. At 3 months, 84% in the immediate PT group and 71% in the rest before PT group demonstrated significant healing, consistent with previous literature reports.5 14 37 38
This study also assessed changes in the functional cross-sectional area of the multifidus on MRI, since muscle atrophy can result from prolonged rest.15 We found significant differences between groups in the change of the functional cross-sectional area of the lumbar multifidus from diagnosis to the 3-month MRI. The immediate PT group increased functional cross-sectional area in the lumbar multifidus, while the rest before PT group demonstrated an overall decrease, with 50% of the participants in this group showing signs of multifidus atrophy. Previous systematic reviews of other populations with LBP revealed that the cross-sectional area of the lumbar multifidus negatively correlates with 12-month LBP and predicts its occurrence.39 40 Among adolescent athletes with LBP, including spondylolysis, reduced functional cross-sectional area was associated with a longer time to return to play.41
We found no significant differences between groups in depressive symptoms, fear avoidance beliefs or quality of life across the study. Our hypothesis that the immediate PT group would have fewer depressive symptoms was unsupported. Low rates of depression in both groups suggest that injury and sport removal may not cause as much depression in this population as we thought. However, two athletes with moderate depressive symptoms were identified in this study, a rate similar to the general population, so clinicians should remain vigilant about depression.42
Limitations
This study has several limitations, including a small sample size (n=64), limiting analysis of individual characteristics (ie, sex, age, sport played and lesion type) and their effects on the intervention. The dropout rate over 1 year was 14%, with an 86% completion rate overall. Retention rate differed substantially between sites, with one (NCH) retaining 45 out of 48 participants (94%) and the other (CHCO) retaining just 10 of 16 (63%), potentially reflecting geographical differences in available resources or participant outcomes. To enhance future research, alternative strategies should be employed to minimise dropout and improve geographical diversity. Additionally, because participants were drawn only from US states (Ohio and Colorado), our findings may not be generalisable to other regions where the treatment of spondylolysis may differ.
Conclusion
We found that adolescent athletes diagnosed with an active lumbar spondylolysis who began PT immediately achieved greater improvement in pain and disability compared with those who rested before PT, with clinically significant difference seen at 1 month. Clinicians may consider prescribing PT immediately after diagnosing active lumbar spondylolysis. Athletes who begin PT immediately may also return to sport sooner and have fewer recurrences of LBP compared with injured athletes who rested before starting PT.
Supplementary material
Acknowledgements
We thank the participants who volunteered for the study and the physiotherapists at Nationwide Children’s Hospital and Children’s Hospital Colorado who delivered treatments.
Footnotes
Funding: This study was funded by the American Medical Society for Sports Medicine Clinical Research Network.
Provenance and peer review: Not commissioned; externally peer reviewed.
Patient consent for publication: Not applicable.
Ethics approval: This study was approved by Nationwide Children’s Hospital and Children’s Hospital Colorado (IRB approval number STUDY00002285). All participants and guardians provided written informed consent before participating.
Data availability free text: We will make the data and associated documentation available to users only under a data-sharing agreement that provides for (1) a commitment to using the data only for research purposes and not to identify any individual participant, (2) a commitment to securing the data using appropriate computer technology and (3) a commitment to destroying or returning the data after analyses are completed. Email requests for data-sharing agreements to Mitchell.Selhorst@Nationwidechildrens.org.
Collaborators: Spondylolysis Physician Group: Aubrey Armento, Steven Cuff, Drew Duerson, Megan Liberty, James MacDonald, Jonathan Napolitano, Thomas Pommering, Amy Valesek, Gregory Walker, Kristina Wilson.
Patient and public involvement: Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Correction notice: This article has been corrected since it published Online First. Figures 3 and 4 have been replaced.
Contributor Information
Spondylolysis Physician Group:
Aubrey Armento, Steven Cuff, Drew Duerson, Megan Liberty, James MacDonald, Jonathan Napolitano, Thomas Pommering, Amy Valesek, Gregory Walker, and Kristina Wilson
Data availability statement
Data are available on reasonable request.
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Data Availability Statement
Data are available on reasonable request.