|
슬개건 병증의 통증성 원심성 트레이닝 논문
panic bird..
The patellar tendon
Anatomy
The patellar tendon is an elongation of the quadriceps tendon, which is the
tendon of the quadriceps muscle. The patellar tendon runs from the patellar
bone to the tendon insertion into the tuberositas tibiae (Fig. 6). The
quadriceps muscle is the largest muscle in the human body and is composed
of four muscle bellies. M. rectus femoris origins from spina iliaca anterior
inferior and inserts via the quadriceps tendon and patellar tendon into the
tuberositas tibiae. The vastus muscles (M. vastus medialis, M. vastus
lateralis and M. vastus intermedius) originate in different locations on the
femur, and insert at the patella and the patellar tendon at the tuberositas
tibiae. The quadriceps muscle is the strongest extensor muscle in the knee
joint. Besides extension in the knee joint, it assists in the hip flexion via M.
rectus femoris. According to Peers et al. the width of the patellar tendon is
approximately 30 mm (in the frontal plane) and the thickness is 4–5 mm (in
the sagittal plane) (Peers, et al. 2005). During its course, there are variations
in the width of the tendon from 31.9 mm at its attachment to the apex of
patella and 27.4 mm at its attachment to the tibial tubercle (Andrikoula, et
al. 2006).
Tendon structure
The structure of the patellar tendon is described previously (page 12).
Circulation
The arterial supply of the human patellar tendon was systematised by
Andrikoula et al. Three arterial pedicles were observed: superior, middle,
and inferior, placed on each side of the patellar tendon. Medial pedicles
originate in the descending and inferior medial genicular arteries. The lateral
pedicles originate in the lateral genicular arteries and the recurrent anterior
tibial artery. Two main vascular arches anastomose these pedicles: the
retropatellar and the supratubercular (Andrikoula, et al. 2006).
Innervation
Recently, the nervous system in the patellar tendon was clarified by
Danielson et al. (Danielson, et al. 2006a). In his thesis, Danielson presented
that the loose paratendinous connective tissue of the patellar tendon was
richly innervated by nerve structures. The paratendinous tissue was more
innervated than the tendon tissue. Parts of the nerve structures were related
to sensory afferents and parts to cholinergic and, especially, sympathetic
nerve fibres. There are limited innervations within the patellar tendon.
However, recently the tenocytes themselves were shown to produce signal
substances, normally associated with neurons (Danielson 2007).
Biomechanics
The patellar tendon is able to transmit high muscle forces to the bone during
movement. Particularly activities like running and jumping can put the
tendon under high stress. The parallel fibre arrangement allows the tendon
to tolerate high strains, but the tendon is not as good at tolerating shearing
forces (Kirkendall, et al. 1997). The highest load on tendons occurs during
eccentric muscle activation, up to three times higher than during concentric
activation (Komi 1984;Fyfe, et al. 1992). It has been estimated that the forces
within the patellar tendon can reach 0.5 kN during level walking, 8.0 kN
when landing from a jump, up to 9.0 kN during fast running, and 14.5 kN (17
times the bodyweight) during competitive weight lifting (Zernicke, et al.
1977).
Patellar tendinopathy
Definitions
Overuse of the patellar tendon has historically been called jumper’s knee
or patellar tendinitis. However, these terms are misnomers. The
condition is found in many patients who do not participate in jumping sports
(Khan, et al. 1996;Cook, et al. 1997;Lian, et al. 2005), and histopathological
studies have consistently shown the underlying pathology to be degenerative
(tendinosis) rather than inflammatory (tendinitis) (Khan, et al.
1996;Alfredson, et al. 2001;Maffulli, et al. 2004). Nowadays it is commonly
agreed that the term patellar tendinopathy should be used for chronic
pain symptoms in a tender area of the tendon (Maffulli, et al. 1998), and
combination of chronic pain in a tender part of the tendon and US, MRI or
biopsy evidence of corresponding changes in the tendon is commonly called
patellar tendinosis (Movin, et al. 1997;Khan, et al. 1999).
Epidemiology
Patellar tendinopathy is most commonly seen in sports with high demands
on speed and power from the leg extensors (Lian, et al. 2005). The highest
prevalence (40–50%) has been reported among male volleyball players
(Ferretti, et al. 1983;Ferretti, et al. 1990;Lian, et al. 1996). Other sports
where the condition is seen include basketball, soccer, football, and track
and field (Blazina, et al. 1973). Overuse of the patellar tendon is also
common among army recruits, constituting 15% of all soft-tissue injuries
(Linenger, et al. 1992). In one of the few epidemiological studies on elite
athletes in different sports, the overall prevalence of patellar tendinopathy
was reported to be 14%. The prevalence was lower in women (5.6%)
compared to men (13.5%) (Lian, et al. 2005). Other clinical studies have also
shown that the condition is more common in men (Myllymaki, et al. 1990).
In junior basketball players the prevalence was shown to be 7% (Cook, et al.
2000a), and in Swedish elite junior volleyball players the prevalence was 11%
(Gisslen, et al. 2005b). The long-term prognosis for male athletes has been
shown to be poor, and 53% of athletes abandoned their sports career due to
pain symptoms (Kettunen, et al. 2002).
Aetiology
The aetiology to patellar tendinopathy is unclear. The condition is associated
with a variety of both intrinsic and extrinsic risk factors, and some
individuals seem more prone to develop tendinopathy than others, despite
participating at similar activity levels. Also, it is more common among younger individuals, in contrast to Achilles tendinopathy, that often is seen
in the middle-aged group (Lian, et al. 2005;Magra, et al. 2008).
Intrinsic risk factors
Poor flexibility in the ankle joint increases the ground reaction forces
during landing, and is associated with patellar tendinopathy (Malliaras
2000). Further, poor flexibility of the hamstrings and quadriceps muscles is
related to the development of patellar tendinopathy (Cook, et al. 2004a).
Weakness/imbalance of the quadriceps and gastrocnemius muscles could
have a role in the development of tendinopathy according to (Gleim, et al.
1997), however, Witvrouw et al. didn’t find any relationship between
weakness in the thigh muscles and patellar tendinopathy (Witvrouw, et al.
2001).
Gender . There are a few studies that show that men are more prone to
sustain patellar tendinopathy than women (Cook, et al. 1998;Lian, et al.
2005). This has been challenged by Witvrouw et al. who found no significant
gender-based differences among patients with patellar tendinopathy
(Witvrouw, et al. 2001).
Bodyweight . A few studies have highlighted high body mass as an
important intrinsic risk factor for the development of patellar tendinopathy
(Gaida, et al. 2004). A high waist-to-hip ratio (WHR) has been found in
volleyball players with patellar tendinopathy (Malliaras, et al. 2007;Gaida, et
al. 2008).
Extrinsic risk factors
Training errors such as increased frequency and duration of training
sessions have been shown to be associated with patellar tendinopathy
(Ferretti 1986;Gisslen, et al. 2007).
Overuse due to repetitive tendon loading during running and jumping is a
strong aetiological factor associated with patellar tendinopathy (Jozsa, et al.
1997). Reports have shown that volleyball players who participated in more
than three training sessions per week were more prone to sustain patellar
tendinopathy than those who participated in less than three sessions per
week (Ferretti 1984). This was supported by Gaida et al. who found a
correlation between training hours per week and the development of patellar
tendinopathy in volleyball players (Gaida, et al. 2004). Underuse. Almekinders et al. investigated the strain in the inferior pole of
the patellar tendon during range of motion while the tendon was loaded
(Almekinders, et al. 2002). The authors reported that the highest tensile
strain was distal to the inferior pole of the patella on the ventral side of the
tendon. The lowest tensile strain was on the dorsal side of the tendon.
Tendinopathy is commonly found on the dorsal side of the proximal tendon.
Investigating the strain in the whole length of the tendon, Basso et al. found
that the highest strain was at the dorsal aspect of the tendon (Basso, et al.
2002). However, this may not reflect what actually occurs at the insertion
into the tip of the patella. It seems that the strain within the tendon is not
uniform, and that there could be an alternative biomechanical explanation
for the pathology found at the enthesis (Maganaris, et al. 2004).
Pathogenesis
Patellar tendinopathy is believed to be a degenerative condition caused by
high loads on the patellar tendon (Cook, et al. 2000a). As in Achilles
tendinopathy, three major causative theories have been suggested, i.e. a
mechanical, a vascular, and a failed healing theory (Curwin 1998;Cook, et al.
2002;Fenwick, et al. 2002). Hamilton and Purdam have presented a new
theory, where the authors proposed a histological adaption of the proximal
patellar tendon, due to compressive loads, possibly leading to a weakness of
the tensile properties of the dorsal aspects of the tendon. The remaining
tensile properties of the tendon and surrounding tissue might be overloaded
and nociceptors activated (Hamilton, et al. 2004). An impingement theory
was presented by Johnson et al. suggesting that impingement between the
inferior pole of the patella and the tendon occurs during knee flexion
(Johnson, et al. 1996). This theory has been criticised by Schmid et al. who
found that during knee flexion in both asymptomatic and symptomatic
individuals, the angle between the patella and the patellar tendon was
decreased. They concluded that the patellar tendon could not be impinged
(Schmid, et al. 2002).
Histology
The histology in the chronic painful patellar tendon is the same as for the
chronic painful Achilles tendon described previously (page 24).
Pain mechanisms
The source of pain in patellar tendinopathy is still unknown. Although
histopathology is present within the tendon, some tendons are painful and
some are not (Cook, et al. 1998;Cook, et al. 2000b). Recent research has
shown that neovascularisation is present in painful patellar tendinopathy, but rarely in the normal tendon. This has given new insight into the source of
pain (Gisslen, et al. 2005a). More pain and deteriorated function is closely
related to the presence of neovascularisation; this has been shown in a study
using US and CD (Cook, et al. 2004b). Substance P (SP) positive nerve fibres,
seen as free nerve endings, have been observed interspersed between
collagen fibres in chronic painful patellar tendons in athletes with pain
symptoms indicating patellar tendinopathy (Lian, et al. 2006). Recently,
acetylcholine (ACh) and catecholamines, which are ordinarily found in the
nervous system, were found to be produced by tendon cells in tendons with
tendinopathy (Danielson, et al. 2006b). This highlights the fact that the
tendon cells themselves could have a key role in the production of pain
substances. This possibly supports the ’biochemical’ hypothesis presented by
Khan et al. (Khan, et al. 2000).
Clinical symptoms
The clinical diagnosis of patellar tendinopathy is based on the patients
subjective reports of pain related to activity. The pain is often localised in the
tendon insertion into the inferior pole of the patella, but pain can also be
located at the tibial attachment of the tendon (Blazina, et al. 1973).
Symptoms often start gradually, and relate to changes in sports activity (e.g.
duration, intensity or frequency). Most often, patients complain of pain after
strenuous activity, leading to impaired performance. In the early stages,
patients only experience pain after activity. As the symptoms progress,
patients may also report pain before and during sport activity. In severe
cases, the patient may complain of pain during daily activity (e.g. ascending
and descending stairs) (Cook, et al. 1998;Cook, et al. 2000b;Peers, et al.
2005).
Clinical examination
The medical history and clinical examination of patients with patellar tendon
injuries are in most cases straight forward. The objective diagnostic tests for
tendinopathy may however not be as valid and reliable as earlier believed
(Cook 2001). Pain during loading and tenderness are always present in
patients with patellar tendinopathy. However, a study by Cook et al. showed
that a tendon may be tender even though no injury exists. During palpation
of the tendon, the knee should be fully extended and the quadriceps muscles
relaxed (Cook, et al. 2001). When the knee is flexed to 900 , the tension in the
tendon increases and tenderness often decreases. A frequently occurring
clinical finding is atrophy of the quadriceps muscles, resulting in weakness
and pain during knee loading activities such as jumping and squatting. The
decline squat is a valuable clinical tool, which increases the load on the
patellar tendon during squats. Pain during squats could be estimated on a visual analogue scale (VAS). The angles of knee flexion were pain occurs
should also be established.
Differential diagnoses
There are several different anatomical structures close to the patellar tendon,
and hence it is sometimes difficult to make a correct diagnosis. Tendon pain
is often well localised in tendinopathy, but if the patient has diffuse pain
symptoms, other diagnoses should be suspected. Pain from the
patellofemoral joint should be excluded. Clinically, it is difficult to
differentiate ch[안내]태그제한으로등록되지않습니다-ondropathology originating in the inferior pole of the patella
from tendon pain (Cook, et al. 2001;Alfredson 2005). Plica formations may
cause symptoms like pain, snapping or popping related to the patellofemoral
joint. This has also been associated with chondral lesions of the patella
(Dupont 1997). Impingement of the infrapatellar fat pad (Hoffa’s disease) is
unusual, but could occur at full knee extension (Kumar, et al. 2007).
Patellofemoral pain syndrome (PFPS) usually goes with pain in the anteromedial
aspect of the patella (Witvrouw, et al. 2005). A partial patellar tendon
rupture can be difficult to differentiate from patellar tendinopathy, but often
appear in relation to high impact activities in athletes, or after a sudden blow
to the tendon. The Osgood-Schlatter syndrome is an inflammation in the
bone and/or cartilage where the patellar tendon attaches to the tibia. The
condition is commonly seen in adolescents during growth spurt, usually in
combination with high activity levels (Medlar, et al. 1978). The Sinding-
Larsen-Johansson disease is also found in adolescents and is believed to be
caused by traction from the patellar tendon in the region of the growth plate
where the proximal patellar tendon attaches (Medlar, et al. 1978).
Treatment
The goal for the treatment of patients with patellar tendinopathy is the same
as for other tendinopathies: to decrease pain and improve physical activity.
Different treatment methods have been recommended, but there is sparse
scientific evidence for most methods used. Corrections of intrinsic and
extrinsic risk factors like training errors, flexibility, biomechanical
abnormalities, and muscle weakness are often initiated.
Rest and NSAIDs are often recommended, however rest is detrimental to
the tendon causing weakness and impaired tendon properties (Kannus, et al.
1997a). Furthermore, there is strong evidence to suggest that there is no
inflammation inside the tendon, at least not in the chronic stage (Alfredson,
et al. 2001). Therefore the use of NSAIDs is considered inappropriate.
Cryotherapy. Besides the analgetic effect, cryotherapy is used to reduce the
metabolic rate in the tendon and decrease the extravasation of blood and
protein from new capillaries found in tendon injuries (Rivenburgh 1992).
Ultrasound that often is used clinically has proven to have no effect in the
treatment of tendinopathies (Stasinopoulos, et al. 2004). Warden et al.
found low-intensity US no better than placebo treatment in a double-blind,
placebo-controlled trial (Warden, et al. 2008).
ESWT has become a popular treatment option for patellar tendinopathy.
However, there are few studies showing clinical effects. Peers et al.
concluded that ESWT contributed to improvement with less pain and better
function in the short-term perspective (Peers, et al. 2003).
Transverse friction massage. Manual therapy techniques are commonly
employed. To our knowledge only one study has evaluated transverse friction
massage in patients with patellar tendinopathy, and no effects on pain and
function were found (Stasinopoulos, et al. 2004).
Strength training. A similar eccentric training protocol as described by
Curwin for Achilles tendinopathy has also been used for patellar
tendinopathy with encouraging results (Curwin 1984). As for Achilles
tendinopathy, eccentric training is considered the cornerstone in a
rehabilitation program for patellar tendinopathy (Peers, et al. 2005).
Different groups have previously studied the effects of an eccentric training
regimen, with varying results (Jensen, et al. 1989;Cannell, et al. 2001).
Injections of sclerosing polidocanol outside of the tendon, where the
vessels enter the tendon, have shown promising results with decreased pain
and return to previous physical activity levels (Alfredson, et al. 2005a).
Surgical treatment methods are similar to those used to treat Achilles
tendinopathies, i.e. most often a longitudinal tendon incision and excision of
abnormal tendon tissue, followed by a period of immobilisation, is used. The
outcomes of surgery for patellar tendinopathy are unpredictable. In a review
of 23 studies, Coleman et al. evaluated the success rate of surgical outcome,
showing varying results (46–100% good results). Interestingly, clinical
results were better in studies of poor scientific design, and less good in
studies with a good scientific design (Coleman, et al. 2000). In a randomised
study by Bahr et al. comparing the results of intra-tendinous surgery with
painful eccentric quadriceps training, there were 45% good results after
surgery and 55% good results after eccentric training (Bahr, et al. 2006).