A twenty six year old male triathlete presented with right sided lateral knee pain. Pain was reported on the VAS scale during activity at 9/10, which developed from an ache to a more sharp stinging pain since onset two months ago. No pain was reported at rest (VAS 0/10). On waking, the right knee feels tight especially the day after training but gets progressively better with gentle movement. Cycling and downhill running especially on uneven surfaces aggravates the symptoms; pain is now experienced at the onset of such activities. The condition has gradually worsened since changing the bike cleat set up to a toe in position three months ago. Contralateral hip tension has accompanied the lateral knee pain. The weekly training programme includes a 10 mile run six times per week at a 6 minute mile pace, cycling 40 miles three times per week and swims 1.5 miles three times per week
Observation revealed foot over pronation causing calcaneal eversion and increased internal tibial rotation. A boney prominence bilaterally at the base of the 3rd metatarsal was palpable and left an indent in the sole of the running shoes. Knee examination revealed right lower back tension on active knee extension. The patient is right handed and left footed which could alter biomechanics of the lower back, especially as rotational forces are required for swimming and running, two of the three disciplines in triathlon. There was no pain on palpation and no other abnormalities were detected with further examination of the knee. Ankle assessment revealed no abnormalities. The hip assessment showed cramping on active medial rotation possibly highlighting weakness of the gluteus medius or tensor facia lata (TFL). Gluteus medius and minimus were weak on the right side.
From the physical examination, special tests were used to elicit the most appropriate treatment and formulation of a working hypothesis, the probable causes of lateral knee pain can be seen in table 1. As the patient has high levels of strength and muscle endurance Trendelenberg’s test was negative before fatigue, however following 30 seconds of deep squats a positive test was observed on the symptomatic side. Obers test showed a twenty degree bilateral difference, with the right side having less range. Modified Thomas showed left side rectus femorus tension and right sided illio tibial band (ITB) tension. Thessaly test showed no positive sign.
|Common||Less common||Not to be missed|
|ITB Friction syndrome||Patellofemoral syndrome||Common peroneal nerve injury|
|cyst||Bicep femoris tendinopothy|
Table 1: Causes of lateral knee pain, diagnosis and probable diagnosis (adapted from Brukner and Khan, 2009).
From the subjective and objective assessment including the type of sport and aggravating and easing factors ITB friction syndrome is the preferred working hypothesis. The ITB passes over the lateral epicondyle between 20-30 degrees of knee flexion commonly used in cycling and running (Pettit and Dolski, 2000). The ITB moves from posterior to anterior over the lateral femoral epicondyle, where it can impinge, commonly on the foot strike in running (Orchard, 1996). This impingement zone increases during downhill running or with incorrect saddle or a toe in cleat set up on the bike (Fredericson and Wolf, 2005). Weak gluteus medius and minimus decrease the control of femoral abduction causing greater stress on the ITB in the stance phase of gait (Orchard, 2006). Due to the high levels of endurance required for triathlon, fatigue towards the closing stages of a race could contribute to the onset of symptoms. This will cause the injury to fluctuate between the repair and remodelling stage of healing (Fredericson and Wolf, 2005). As the patients has over foot pronation, this predisposes him to further internal tibial rotation. The current biomechanical set up for cycling and running could cause friction of the ITB as it passes over the lateral epicondyle of the knee (Williems et al. 2001, Noehren et al. 2007).
ITB friction syndrome is the most common cause of lateral knee pain and accounts for 1.6-12% of injuries in runners and 15% of all overuse injuries in cyclists, commonly treated clinically without the need for imaging or surgery (Lavine, 2010). There is some debate over the cause of the syndrome. The most common cause is friction of ITB over the lateral femoral epicondyle and irritation if the ITB (Frederickson and Wolf, 2005). Although Fairclough et al. (2007) claim that compression of the fat pad and connective tissue of the ITB is irritated through overuse. Despite the lack of congruency in the literature, ITB friction syndrome is typically treated within 6 weeks (Frederickson et al. 2005).
Short Term Goals
Rest from aggravating factors, (cycling and running) or a reduction in training load and intensity is required to reduce the symptoms (Nusman et al. 2010). The patient is advised to swim in order to maintain cardiovascular fitness. The RICE protocol should be used after any activity to reduce any inflammation (Frederickson et al. 2006).
Stretching the ITB (appendix 2) is a common treatment for ITB friction syndrome (Frederickson et al. 2002). Tightness of the TFL can cause the ITB to reduce in length causing irritation the lateral knee. Stretching will produce plastic deformation of the collagen cross bridges which will reform in a striated formation and increase the length of the TFL and in turn the ITB (Prentice, 2011). The effectiveness is questionable due to the ITB being a band of connective tissue that has a lesser ability to respond to stretching and its length can be improved by 3-5% (Frederickson et al. 2002) and results vary from individual to individual (Falvey et al. 2009). Stretching the TFL due to its muscular nature will respond normally to stretching, thus increase in length allowing the ITB.
Firing patterns and strengthening
Weakness of gluteus medius and minimus often causes a lack of muscle balance and firing patterns at the hip. To correct imbalance, muscle firing patterns of the gluteus maximus and hamstrings were tested bilaterally (appendix 3). The hamstrings were overactive on hip extension, whereas the more powerful gluteus maximus should be used in linear movement for cycling and running (Prentice, 2011). If the correct firing pattern is corrected the subsequent muscle strengthening programme will be more effective (Pettit and Dolski, 2000). Eccentric strengthening exercises (appendix 4) are best for improving pelvic control and improves biomechanics during cycling and running (Lavine 2010).
Massage and trigger pointing
Massage and trigger pointing using a foam roller (appendix 5) are effective treatments for ITB friction syndrome (Wanich et al. 2007). Massage was applied to the quadriceps, TFL, ITB and hamstrings (overuse) to break down adhesions and realigning muscle fibres in a striated formation to restore muscle tensile strength and function (Fritz, 2005). Trigger points in the gluteus medius and maximus can cause referred pain which could exacerbate the symptoms at the knee. Analgesic effects from massage by inhibition of pain reception via the pain gate theory could also be beneficial (Melzack and Wall, 1965).
Short term Correction of biomechanics to achieve long term goals
To address the cause of the problem biomechanical analysis of the running gait cycle and bike set up is important. The patient has a preferred running style on his toes due to the boney prominance at the base of 3rd. This will increase knee flexion at ground strike and thus put the ITB in the impingement zone more frequently over an endurance race. A heel strike is important to spread the load on the ground and decrease knee flexion out of the impingement zone (Farrell et al. 2003). More cushioning in the running shoes could also improve running kinematics and reduce discomfort for the patient (Bruckner and Khan, 2009).
A saddle height which is too high will put the patient in the impingement zone at the bottom of the cycle phase and increase lateral movement of the pelvis. This lateral movement will increase the tension of the TFL and fatigue the gluteal muscles as the distances increase causing overworked hamstrings and quadriceps. Lowering the seat height is recommended to decrease lateral movement at the hip and ITB impingement. As the athlete may lose power in this position, a saddle forward position will increase the recruitment of quadriceps, hamstrings and gluteus maximus to address the power loss (Bruckner and Khan, 2009). A toe in cleat set up on the bike will also increase the friction of the ITB (Farrell et al. 2003) as it passes over the lateral epicondyle, due to its anatomical insertion onto gerdys tubercle. A more neutral position (appendix 6) will decrease shear forces at the knee and subsequently address the cause of the problem (Wanich et al. 2007). Practice in this position to retrain the neuromuscular system by gradually increasing distances will encourage the correct muscle recruitment pattern through the kinetic chain (REF).
It is unclear of the actual causes of ITB friction syndrome. Clinical treatment will not differ but of symptoms do not subside after six weeks surgical treatment could be considered. Triathlon requires repetitive movement for sustained periods of time which induces fatigue. Incorrect biomechanics due to poor running gait and bike set up can contribute to imbalances at the hip. Avoidance of aggravating factors, RICE during the inflammation phase and firing patterns stretching and strengthening should commence in the sub acute phase. Once imbalances have been addressed a gradual return to activity will improve integration of recruitment patterns in the kinetic chain. Running mechanics and cycling position will need to be corrected prevent relapse of the ITB friction syndrome. Treatment typically takes six weeks.