Effects of Lower extremity proprioception training on basketball athletes with patellofemoral pain syndrome
Congke Sun
Abstract
Background
  The ability of one leg stability is associated with knee discomfort and patella pain (PFPS). But little research was done on whether Lower extremity proprioception training would be more effective than physical therapy on the Rehabilitation of patella pain.
 
Methods
  We will conduct a prospective, single blind, randomized controlled trial on 60 patients with patellofemoral pain. Individuals will be assigned indiscriminately to an intervention group and a physical therapy group.
  Lower extremity proprioception training includes muscle strength training, balance training, and knee joint proprioception training, and the physical therapy group will be given the therapy for the same amount of time as Lower extremity proprioception training group.
  The main outcome measures include adverse events, pain visual analogue scale, and knee anterior pain scale index, a knee joint function self-reported questionnaire used to evaluate knee joint function, especially in PFPS patients. Secondary outcome indicators are muscle strength and endurance of the knee flexors and extensors, proprioceptive sensation of the knee, muscle thickness of the quadriceps femoris, and one-year follow-up. We will conduct intention to treat analysis on individuals who withdrew from this study.
 
Discussion
  According to previous research, only physical therapy is a common treatment method for PFPS patients. In this study, we will conduct lower limb proprioception training for PFPS patients. We believe that this study can demonstrate the effectiveness of lower limb proprioception training on PFPS.
 
Keywords
  Patellofemoral pain syndrome, lower limb proprioception training, physical therapy
 
Background
  patellofemoral pain syndrome (PFPS) is a common cause for “anterior knee pain” and mainly affects young women without any structural changes such as increased Q-angle or significant pathological changes in articular cartilage. The incidence of “anterior knee pain” is high and is located at 22/1,000 persons per year. Women are affected about more than twice as often as men. The causes for anterior knee pain are multifactorial. These include overuse injuries of the extensor apparatus (tendonitis, insertional tendinosis), patellar instability, chondral and osteochondral damage. The Therefore, PFPS is a diagnosis of exclusion.
 
  The most common treatment for PFPS is Physical therapy: Suitable for patients with mild or early patellar pain. Physical therapy includes hot compress, cold compress, massage, physical therapy, etc. Hot compress can promote blood circulation, relieve pain and muscle tension; Cold compress can reduce inflammation and swelling; Massage and physical therapy can alleviate muscle spasms and improve muscle strength. The use of physical therapy equipment (such as ultrasonic therapy equipment, electric therapy equipment, etc.) suitable for patients with symptoms such as muscle spasms and muscle relaxation. Drug treatment and surgery are also considered when conservative treatments weren’t working.
 
  Among these therapies, physical therapy is currently the most concerned, but currently there is not much focus on training methods for knee stability and proprioception in PFPS research. Therefore, our paper will explore how a set of self-designed Lower limb proprioception training would help the recovering process of PFPS.
 
 
 
Hypothesis
  1, Both single leg stability training and traditional physical therapy have a positive impact on the treatment of patella pain among basketball athletes.
 
  2, Single leg stability training will have a more significant help on the rehabilitation of patella pain among basketball athletes.
 
 
 
Methods
Sample size estimation
  According to the previous studies, the effect size of Kujala Patellofemoral Scale is in the range of 0.34–0.54. Pain intensity effect size is in the range of 0.45–0.56. In this study, we used G-Power Software: F-test, ANOVA: one-way repeated measures (version 3.1.9.2) with the following parameters: effect size = 0.3; test level = 0.05; test efficacy = 0.95; group numbers = 3, number of measurements = 3. The total sample size of this study should be a minimum of 60 participants in the three groups, or 20 participants in each group.
 
Purpose of the study:
  This study will give patients with patella pain treatments including physical therapy and single leg stability training to determine the following:
 
  1, Whether Lower limb proprioception training is effective for treating patella pain
 
  2, whether Lower limb proprioception training exercise has more advantageous effects than physical therapy (ultrasonic) for basketball athletes with patella pain.
 
  3, The adverse effects of Lower limb proprioception training exercise.
 
Study design
  We will design a single blind randomized controlled trial to compare Lower limb proprioception training with regular physical therapy(ultrasonic and Electrical stimulation) (Figure 1). We will recruit and investigate 120 PFPS patients from various student basketball teams in Shanghai, China, including high school teams participating in Nike elite League and JR NBA, as well as university basketball teams participating in Cuba division 1.
Before starting the study, everyone will fill out a questionnaire that includes basic personal information such as age, educational background, and injury history& BMI. The questionnaire will also include sections on pain intensity (Visual Analog Scale [VAS]) and knee joint function (Anterior Knee Pain Scale [AKPS]). Prior to being selected, written consent from all participants will be obtained.
  All individuals eligible for the study will be randomly assigned by the computer in a 1:1 ratio. After the ward, PFPS patients were divided into a control group (physical therapy group) and an intervention group (Single leg stability training). The entire study will last for six months, including three months of intervention and an additional three months of non intervention follow-up period.
  The assessment will be conducted before intervention, six weeks, three months, and six months.
 
 
 
 
Participants
Inclusion and exclusion criteria
  The participants should meet the following requirements: (1) aged 16-22; (2) patella pain lasting longer than a month; (3) Being a basketball student athlete at any level; (4) anterior or retropatellar knee pain from at least two of the following: prolonged sitting; climbing stairs; squatting; running; kneeling; and hopping/jumping; (5) The pain should be caused by exercise (during basketball trainings or games); (6) BMI should be in the range of 18.5-24.99 kg/m^2; (7) no injuries to the knee other than patella pain (such as torn meniscus) or history of other knee injuries; (8) the patellofemoral joint extrusion test is positive. The exclusion criteria are as follows: (1) meniscus injury; (2) laxity of articular ligament; (3) pressure pain on the tibial tract, the goose foot tendon, and patellar ligament; (4) effusion of knee joint; (5) history of patellar dislocation; (6) severe cardiovascular or osteoporosis, progressive neurological deficits; (7) pregnancy women or lactating women; (8) VAS score (in the range of 1–10) > 8; and (9) VAS score (in the range of 1–10) < 3.
 
Withdrawal criteria and management
  Patella pain patients will be asked or be allowed to quit the study if:
1, they have such a demand;
2, they are diagnosed with a severe disease, such as cardiovascular disease;
3, they obtain a side effect because of treatment;
 
Interventions
  All groups will receive basic information and intervention details separately before entering the study. Individuals will be required to fill out a form to record the duration and times of the intervention. Patients need to maintain a normal lifestyle and avoid receiving any other rehabilitation treatment.
 
Single leg stability training exercise group
  Athletes assigned to this group will undergo a three-week single leg stability training, which includes strengthening the quadriceps muscle strength of the single leg, strengthening the hamstring and buttocks muscles, and maintaining core stability while standing on one leg. This set of actions includes a total of four actions:
 
Training moves introduction
  1，Start with a slight bend in the knee, then perform a single leg squat, with healthy legs extending forward, backward, left, right, and four directions in the air. Each of these four movements is considered a group, repeat them for five times as a group. Rest for 30 seconds between groups, and do a total of three groups.
 
 
 
  2，Single Leg Hip Bridge: Lie on the ground, slightly bend the injured leg and place it on the ground, with the other foot in the air. Slowly use the foot on the ground to support your body, doing 10 times as a group. Rest for 30 seconds between groups, and do a total of three groups.
 
 
 
  3，The starting position is a lunge, with the affected foot in front, holding a dumbbell (five kilograms, depending on the patient's condition, within a painless range) in your hand. Use the front foot to push yourself up and do the movements as slowly as possible. After pushing yourself up, hold it steady for one second as shown in Figure 2, and then slowly continue. Count 8 movements into one group, do three groups, and rest for one minute between groups
 
 
  4，The starting position is to slightly bend and support the affected foot on one leg, with both arms facing forward to maintain body balance. You can hold a basketball or yoga ball in your hand, and the trainer needs to apply external force to this ball from top to bottom, left to right. The patient's core should exert force, with one leg supported to prevent severe body shaking and maintain balance. 30 second group, do three groups, and rest between groups for 30 seconds
 
 
Training plan
  In the first month, only perform actions 1 and 4, both of which have relatively low knee joint strength and pressure and are suitable for early recovery. Each of these four movements in move 1 is considered as one action, repeat them for five times as a group. Rest for 30 seconds between groups, and do a total of three groups. For move number 4, 30 second group, do three groups, and rest between groups for 30 seconds. After completing the training movements, relax the muscles of the whole lower limbs. First, use the foam shaft to relax the lower legs, hamstring, front thigh and gluteus muscles, and then carry out static stretching
 
  For the second month, we will add Action 2 and Action 3. For move 3, we will use a 5kg weight, count 8 movements into one group, do three groups, and rest for one minute between groups. For action 2, we will do 10 times as a group. Rest for 30 seconds between groups, and do a total of three groups.
 
  For the last month, we will add some intensity to the training, we will cut down each rest time by 15 seconds and do 3-5 more times in one raps, we will also increase the weight the patient is holding by 2-5 kg.
 
  warning! All intensity increases need to be within a painless range. If the patient feels pain, the training intensity needs to be reduced and immediately stopped. And the intensity of the increase is also determined by the different rehabilitation situations of each patient
 
 
 
Physical therapy group
  In this group, doctors will perform ultrasound physical therapy on patients three times a week, while also helping them relax related muscle groups. But this group of patients will not receive single leg stability training, and doctors will only verbally tell them that they should do some strength training.
 
Outcome measures
Primary outcome measures
  1, We will use VAS scores to evaluate pain intensity. Typically, VAS includes a horizontal line with a length of 100 mm and a pain level of 0-10, where "0" represents no pain and "10" represents unbearable pain. We will first have the patient perform a series of movements, such as going up and down stairs, running, squatting, and jumping. And press the patient's affected knee, and after completing these movements, we will have the patient describe their pain response to these movements using the vas system. The intensity of pain is described by the patient, who points to a number in the line
 
  2, A knee joint function self-report questionnaire survey will be conducted. AKPS will be used to evaluate the results. The Chinese translation of AKPS is a reliable and effective questionnaire for PFPS patients. This is a 13 item self-reported questionnaire for the knee, used to record patients' reactions to six different activities that may be particularly related to PFPS syndrome. AKPS is used to record the duration of symptoms and affected limbs. The highest score is 100 points, with the lower score indicating severe pain or severe knee joint function.
  3, The adverse events, which have correlations with one leg stability training, will be recorded.
 
Secondary outcome measures
  1, The strength and endurance indicators of the quadriceps femoris will be tested using the CON-TREX multi joint isokinetic testing and training machine (CMV AG, D ü bendorf, Switzerland). The maximum concentric contraction of individual knee flexors and extensors will be recorded at different angular velocities of 60 °/s, 120 °/s, and 180 °/s. The muscle endurance index will be calculated based on the ratio of the workload completed during the last five contractions to the workload completed during the first five contractions. The parameters will be recorded as peak torque (Newton meters), peak torque/weight, and power
Output (power) is in watts, and work (work) is in joules
 
  2, The proprioceptive ability of the knee joint will also be evaluated using CON-TREX multi joint isokinetic testing and training machines. These people will be required to move to a random position, hold this position for 3 seconds, and then repeat from the starting position to the reference position. Next, participants will find the position they believe is closest to just now and maintain it. The assessor will measure the position and angle. The proprioception test of the knee joint will be repeated three times, and the final result will be taken as the average. High absolute error means poor proprioception
 
  3, The muscle thickness of the quadriceps femoris will be determined. We will use a portable musculoskeletal ultrasound instrument (M7 Super Series, Mindray, USA) to evaluate four different types of muscles: rectus femoris, medial femoris, lateral femoris, and medial femoris. The method we will follow is based on Giles' research
 
  4, For a basketball player, there is a high possibility of getting injured again after recovery, and the second injury after recovery will also become one of the indicators for us to evaluate the recovery situation. All athletes participating in the experiment will receive our one-year tracking and follow-up to record their knee injuries. We will record the number of secondary injuries in each group and compare which group is less likely to be injured again, indicating better rehabilitation outcomes
 
statistical analysis
  Statistical analysis will be conducted using SPSS 22.0 and Microsoft Excel 2012 software. The data will be represented as mean ± standard deviation. We will use two-way repeated measurement analysis of variance (group × Compare the effectiveness of the neuromuscular training exercise group with the tape and control group, including primary and secondary outcomes. If an individual is lost during follow-up, an intention to treat analysis will be conducted. A t-test will be conducted to compare the changes in measured values within each group. When the P-value is less than 0.05, statistical significance will be considered
 
 
 
Discussion
  Doing lower extremity proprioception training could improve the patients’ overall strength and stability ability. On the other hand, traditional physical therapies could only cure the injury itself. As a basketball athlete, we expect lower extremity proprioception training could help them get back to court faster and minimize the possibility of second time injury. Combining all these aspects, lower limb proprioception training will likely to have an advantage comparing to physical therapies. Various research had found out that one of the main causes of PFPS is not enough muscle strength.
“The current evidence indicates based on few prospective and clinical trials that much more research is needed to clarify, more robustly, the possible causal factors of PFPS. For this reason, other variables, such as structural factors of the knee, weakness of the quadriceps, dysfunction of distal segment, task dependency, neurophysiological factors, such as cognitive and behavioral factors and patient education should be considered both at the moment of evaluation and when recommending preventive and therapeutic approaches to patients.”
  A research done by Rabelo concluded that hip strength and neurophysiological as well as quadriceps can all cause PFPS to occur. For muscle strength is a contributing causation of PFPS, lower limb proprioception training would definitely help the rehabilitation process.
“Up to 78% of PFPS patients report chronic pain 5–20 years after
rehabilitation” (Kasitinon et al., 2021)
  What’s more, recent study had showed that 78% of the patient suffered from knee pain even after rehabilitation. The advantage of doing lower limb proprioception training would show in preventing second time injury comparing to physical therapy.
 
 
 
Strength and limitation
1. Advantages (it is an intervention study lasting for six months)
2. Separated the participants into two groups
3. Unique and self-designed training plan and movements
4. Disadvantages: Didn’t follow-up the patients, no survey of the general healthy population. Since we focused on only athletes, the result can be generalized.
 
 
 
 
 
 
Reference list
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