Activity Modification and Load Management of Adolescents With Patellofemoral Pain
4 supervised sessions were enough to achieve a high success rate in young patients with patellofemoral pain
These subjective improvements were supported by improvements in hip and knee torque
This program may help to avoid pain flare-ups while gradually increasing the capacity of the knee
Introduction
Patellofemoral pain is a condition by which young active athletes are often affected. It is known that exercise therapy forms the cornerstone of treatment, but often poor long-term outcomes are seen, with many relapsing individuals. One of the reasons therefore may be that activity modification and proper load management are often overlooked. High repetitive loading of the knee during the transition to adolescence with insufficient recovery is thought to be one of the main drivers for the development of patellofemoral pain. Exercise is good as it helps build capacity but exercise alone neglects the impact of the frequent bouts of repetitive loading on the knee. To overcome this, this study aimed to investigate the effects of a treatment strategy for adolescents that focuses on activity modification and load management for patellofemoral pain.
Methods
A prospective cohort study included adolescents with patellofemoral pain from 10 to 14 years. The diagnosis was made a trained physiotherapist according to the following criteria:
- Insidious onset of anterior or retropatellar knee pain for >6 weeks and
- Pain provoked by at least 2 of the following positions or functions
- prolonged sitting or kneeling, squatting, running, hopping, or stair walking; tenderness on palpation of the patella or pain with stepping down or double-legged squatting;
- And worst pain experienced during the previous week reported as >30 mm on a 100-mm visual analog scale.
They underwent a 12-week intervention focussing on activity modification and gradual re-exposure to increasing knee joint loads. This program consisted of a reduction in sports participation and avoidance of pain-aggravating activities in the first 4 weeks with strengthening supine bridges and static knee extensions against a wall. This was followed by side-lying hip abduction, seated knee extension, clams and semi squats and this phase also contained the gradual return to activity using an activity ladder. The procedures were explained to the participants and their parents and they both needed to attend 4 supervised visits over the 12-week course.
The activity ladder guided a gradual return to a specific activity, beginning with a warm-up and followed by 15 minutes of performing the activity. Every week, 5 minutes could be added, if pain did not exceed the “OK-zone”.
Progressions could be made when a specific activity of the ladder could be performed within the “OK zone”, without a pain flare-up. The OK zone was defined as a numeric rating scale from 0 – meaning no pain to 10 – corresponding to the worst pain imaginable. When pain during the activity was between 0 and 2, this was considered OK
In the phase before returning to sport (weeks 9 to 12), exercises like standing hip abduction, lunges, squats, and standing hip extensions were performed. Return to training was allowed when level 6 on the activity ladder with no pain flare-up and no pain exceeding the “OK-zone” was reached. When the athlete was able to participate in the full training for 2 weeks without pain, full return to sports was possible. Together with the pain monitoring and activity ladder, educational material was used to increase the participant’s understanding of the why and how.
The primary outcome measure was the self-reported recovery on a 7-point global rating of change (GROC) scale ranging from “much improved” to “much worse” at 12 weeks. Next to some patient-reported outcome measures, isometric knee extension, hip abduction, and hip extension torque were measured.
Results
151 adolescents were included to research this program focusing on load management for patellofemoral pain. They had pain for about 18 months and nearly one third already sought treatment for their injury before.
After 12 weeks, 86% reported a successful subjective outcome, defined as “having improved” or “having much improved”. This was somewhat lower at 6 months and at 12 months where respectively 77% and 81% reported successful outcomes. Yet, this is an important achievement, knowing that in earlier trials, often a successful outcome is only observed in a minority of adolescents, while much greater benefit is seen in adults. Satisfaction at 12 weeks was high; 74% of participants reported being very satisfied with the result of treatment.
Adolescents reported large improvements in knee pain and function and a 20% to 33% increase in hip and knee torque.
Adherence was not spectacular; In block 1, 51%-59% of adolescents with available follow-up data were categorized as adherent (they performed >80% of the isometric quadriceps activation and double-limb bridges). In block 2, 57% performed >80% of the exercises, and 44% performed >80% of the exercises during block 3.
Questions and thoughts
In this study, adherence was quite low, and despite this good outcomes were seen. Especially when comparing these results with other trials which defined a successful outcome in the same way. Therefore the modification of the sports and activities together with the gradual reintroduction of aggravating activities seems a crucial step. “This could avoid the ‘‘all or nothing’’ approach that some patients take if not guided”. The authors also point at the young sample, in contrast to older samples in other studies. It may be possible that younger individuals have a better natural history, or they are more supervised by their parents for example.
The improvements measured on the KOOS scale (secondary outcome) stagnated after 12 weeks, and after 12 months the mean KOOS– Sport/Recreation was 83 points, which is still lower than the mean 100 points for controls with a similar age. Despite the reported improvement in the GROC, the sustained impairments in sports function and participation indicate that this is a long-term condition that needs ongoing management.
The self-reported weekly sports participation was overall increased from inclusion to 12 months. This suggests that quite a large proportion were able to return and even increase their activity levels after the intervention.
Talk nerdy to me
No control group was included in this study, so these results should be carefully interpreted. However, given the present study exceeds previous trials in terms of successful outcomes, it can be concluded that this pain monitoring and activity modifying approach contains a lot of clinical value and can guide these interventions right away. Also in light of the longstanding complaints (at baseline it became clear that these patients suffered from their patellofemoral pain for a long time and most of them for more than 1 year), these results are encouraging. And also surprising! As only 4 supervised sessions were held…
A strong plus of this study is the fact that it used an objective measure to quantify the extent of activity modification. Rather than the “easy method” to ask patients whether or not they reduced their activities (which can be biased), this study used actigraphs for at least 1 week. Therefore we can assume that the reported adherence to refraining from sports participation in block 1 was respected by most (almost 80%).
Take home messages
This prospective study showed that important improvements in patellofemoral complaints can be obtained with a 12-week program focussing on activity modification. Over 12 weeks besides strengthening of hip and knee joint muscles, athletes were gradually reintroduced to their activities with the help of an activity ladder and a pain monitoring model. At 12 months still, 81% of athletes achieved a successful outcome, which demonstrates the power of the progressive increase of loads using a gradual loading protocol together with a pain monitoring model. This way, pain flare-ups can be avoided, and gradually the capacity of the knee can be increased.
Reference
Additional references
In this video I took a look at a quick provocation test for patellofemoral pain you can use right away in practice:
In the following video, we discussed a 6-week intervention program by Greaves et al.
And last but not least, in this video Max discusses the patellofemoral pain consensus statement:
THE ROLE OF THE VMO & QUADS IN PFP
Watch this FREE 2-PART VIDEO LECTURE by knee pain expert Claire Robertson who dissects the literature on the topic and how it impacts clinical practice.
