Recent studies1,2,3 have demonstrated that manipulation of the sacroiliac joint and lumbopelvic region (SMT) can result in a reduction of quadriceps inhibition1,2, or increased quadriceps strength3 in patients with PFPS. However, all three studies did not include measures of symptomatic response, and overall, this literature must be considered preliminary.
This study aimed to build on these previous studies to determine the value of certain clinical examination procedures for predicting which patients with PFPS, if any, would experience a positive immediate response to lumbopelvic manipulation. This type of prospective cohort/predictive validity study is the first step in developing a Clinical Prediction Rule for SMT/PFPS, a tool designed to assist clinicians to choose appropriate interventions based on a group of symptoms and/or examination findings.
Fifty subjects between the ages of 18-50 years old with a diagnosis of PFPS were included in this study. PFPS was diagnosed based on the presence of anterior knee pain provoked by two or more of the following: squatting, prolonged sitting, stair ascent, stair descent, kneeling, or isometric quadriceps contraction. Subjects were excluded if they were pregnant, had signs of nerve root compromise, had any positive knee ligament or meniscus test, palpatory tenderness of the tibiofemoral joint line or patellar tendon, prior surgery to the spine or symptomatic knee, osteoporosis or systemic disease, or were receiving any treatment for their knee pain.
Each subject made one clinical visit, where they underwent a standardized physical examination, followed by three functional tests: 20cm step-up, 20cm step-down, and squatting. Patients then completed two outcome measures – a Numeric Pain Rating Score (NPRS) and a Global Rating of Change questionnaire (GROC) for each task. Each subject then received a supine lumbopelvic manipulation -similar to that used by Childs, Fritz et al. in the development of the LBP Clinical Prediction Rule -– before repeating the functional tests and NPRS/GROC outcome measures. Subjects were then classified as a treatment success or non-success based on a 50 per cent improvement on the NPRS or a score of at least +4 – i.e., moderately better – on the GROC. A binary logistic regression model was used to attempt development of a CPR for predicting success with SMT.
Pertinent findings of this study include:
• 22 of 49 subjects (1 was not included in the analysis) were considered to be a treatment success – all 22 were a success based on a 50 per cent NPRS improvement while 17 of 22 scored minimum 4+ on the GROC – that is, 45 per cent of subjects had symptomatic relief with SMT
• NPRS improvement in the treatment success group was roughly 80 per cent, while in the non-success group it was only 12 per cent
• based on the regression model, five characteristics were identified as a diagnostic test item cluster that could potentially for a CPR:
difference in hip internal
rotation side to side > 14° (*)
ankle dorsiflexion with knee
flexed > 16°
navicular drop > 3mm
no stiffness with sitting > 20 minutes
squatting is the most painful
* the most robust predictor of success was a side-to-side difference in hip internal rotation > 14° (positive likelihood ratio 4.9) – if this factor was present, probability of treatment success increased to 80 per cent
• the presence of three of the five predictors raised probability of treatment success to 94 per cent.
Conclusions and Practical Application:
This study establishes a starting point for developing a CPR for spinal manipulation in those with PFPS. The results must be expanded and replicated before concrete recommendations can be made. However, the authors suggest that clinicians could, with some confidence, utilize SMT in those patients with a difference in hip internal rotation > 14°. This is the take home, potentially applicable message, from this study.
Further studies will provide further clarity on this issue, as this study was underpowered to detect a cause and effect relation between SMT and symptom improvement.
Anecdotally, chiropractors claim success in treating PFPS with lumbopelvic manipulation. This study represents an important step in establishing a base of evidence to support this practice.
1) Suter E, McMorland G, Herzog W, Bray R. Conservative lower back treatment reduces inhibition in knee-extensor muscles: a randomized controlled trial. Journal of Manipulative and Physiological Therapeutics 2000; 23: 76-80.
2) Suter E, McMorland G, Herzog W, Bray R. Decrease in quadriceps inhibition after sacroiliac joint manipulation in patients with anterior knee pain. Journal of Manipulative and Physiological Therapeutics 1999; 22: 149-153.
3) Hillerman B, Gomes AN, Korporaal C, Jackson D. A pilot study comparing the effects of spinal manipulative therapy with those of extra-spinal manipulative therapy on quadriceps muscle strength. Journal of Manipulative and Physiological Therapeutics 2006; 29: 145-149.•