Tendon disorders are a major problem in sports and occu- pational medicine. Tendons have a high tensile strength thanks to a high proportion of collagen in their fibers and a closely packed parallel arrangement in the direction of force [1]. The individual collagen fibrils are arranged into fascicles which contain blood vessels, nerve fibers and lymph. Specialized fibroblasts, tenocytes, lie within these fascicles, and exhibit high structural organization [2]. At histology, tenocytes appear as star shaped cells in cross sections. In longitudinal sections, they are arranged in rows following the direction of the tendon fibers. This specialized arrangement is related to their function, as tenocytes synthesize both fibrillar and nonfibrillar components of the extracellular matrix, and are able to reabsorb collagen fibrils [3]. The fascicles themselves are enclosed by epitenon, which is surrounded by the paratenon, and the potential space between them is filled by a thin, lubricating film of fluid which allows gliding of the tendon during motion.
The pathologic label “tendinosis” has been in use for more than 2 decades to describe collagen degeneration in tendinopathy [4]. Despite that, many clinicians still use the term “tendinitis,” thus implying that the fundamental problem is inflammatory [5]. We advocate the use of the term tendinopathy as a generic descriptor of the clinical conditions in and around tendons arising from overuse [6,7]. The terms tendinosis and tendinitis should be used after histopathological examination [8].
Tendinosis is defined [1] as intratendinous degenera- tion (i.e. hypoxic, mucoid or myxoid, hyaline, fatty, fibrinoid, calcific or some combination of these), due to a variety of causes (aging, microtrauma, vascular com- promise, etc.). Histologically, there is noninflammatory intratendinous collagen degeneration with fiber disorien- tation and thinning, hypercellularity, scattered vascular ingrowth, and increased interfibrillar glycosaminoglycans [1,6,9–11]. Tendinosis is a failure of cell matrix adaptation to trauma due to an imbalance between matrix degener- ation and synthesis [5,10]. Macroscopically, the affected
portions of the tendon lose their normal glistening white appearance and become gray and amorphous. The thick- ening can be diffuse, fusiform or nodular [12].
The paratenon can be involved in the early phases of tendinopathy, and may present as “peritendinitis crepi- tans” due to adhesion between the tendon and the paratenon. Histologically, tendinosis shows partial dis- ruption in tendon fibers. Tendinosis can be asymptomatic:
for example, most patients with an Achilles tendon rupture did not have a clinical picture of tendinopathy before the rupture, and only histology reveals the pro- found intra-tendinous changes. Tendinosis may also coexist with symptomatic paratendinopathy [5,13].
Pain in Tendinopathy
Four types of nerve endings can normally be identified in tendons. The Ruffini corpuscles, free nerve endings, Pacini corpuscles mainly at the tendon site and the Golgi tendon organs mainly at the muscular site [14]. The source of pain in tendinopathy is still under investigation.
Classically, pain was attributed to inflammatory pro- cesses, but, as it has become evident that tendin- opathies are degenerative, not inflammatory conditions, recently the combination of mechanical and biochemical causes has become more attractive [15,16]. Tendon degen- eration with mechanical breakdown of collagen could theoretically explain the pain mechanism, but clinical and surgical observations challenge this view [16]. The bio- chemical model has become appealing, as many chemical irritant and neurotransmitters may generate pain in tendinopathy. High concentrations of the neurotrans- mitter glutamate in patients with Achilles tendinopathy have recently been found [17]. The tendons in these pa- tients showed no signs of inflammation, as indicated by the normal prostaglandin E2 levels [17]. Substance P and chondroitin sulphate may also be involved in producing pain in tendinopathy [15].
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Surgery for Chronic Overuse Tendon Problems in Athletes
Nicola Maffulli, Per Renström, and Wayne B. Leadbetter
Complete or modified rest from sport, non-steroidal anti-inflammatory drugs, cryotherapy, deep frictional massage, ultrasound therapy, pulsed electro-magnetic fields, laser therapy, orthoses, and eccentric exercises [18,19] have all been described in the management of tendinopathy, together with local peritendinous injec- tions of steroids or aprotinin [2]. If these measures fail, surgery is an option [15,16,20]. In the absence of frank tears, the traditional operation involves a longitudinal skin incision over the tendon [21,22], paratenon incision and stripping, multiple longitudinal tenotomies, and, if a definite area of degeneration is found, its excision [15,16,23]. Surgery aims to promote wound repair induced by a modulation of the tendon cell-matrix envi- ronment [20], but even in very experienced surgeons the rate of complications can be high [24,25], and success is not guaranteed [26].
Treatment of chronic tendinopathy aims to allow patients to return to normal level of physical activity [15,16,20]. Percutaneous needling of the tendon for such purpose has been recently reported, even though no results have been published [20], and open longitudinal tenotomy has been long established [15,16,23].
Biology of Tendon Healing
Tendon healing is classically considered to occur through extrinsic and intrinsic healing. The intrinsic model pro- duces obliteration of the tendon and its tendon sheath.
Healing of the defect involves 2 phases, an exudative and a formative phase which, on the whole, are very similar to those associated with skin wound healing [27]. Extrin- sic healing occurs through the migration of tenocytes into the defect from the ends of the tendon sheath [28].
This process classically occurs in 3 phases: inflammation, repair, and organization or remodeling. In the inflamma- tory phase, 3 to 7 days after the injury, cells migrate from the extrinsic peritendinous tissue such as the tendon sheath, periosteum, subcutaneous tissue and fascicles, as well as from the epitenon and endotenon [29]. Initially, the extrinsic response, which far outweighs the intrinsic one, results in rapid filling of the defect with granulation tissue, tissue debris and hematoma. The migrating teno- cytes play a phagocytic role, and are arranged in a radial fashion in relation to the direction of the fibers of the tendon [2]. Biomechanical stability is given by fibrin.
The migrated tenocytes begin to synthesize collagen around day 5. Initially, these collagen fibers are randomly orientated. Tenocytes become the main cell type, and over the next 5 weeks collagen is continuously synthe- sized. During the fourth week, a noticeable increase in proliferation of tenocytes of intrinsic origin, mainly from the endotenon, takes place.These cells take over the main role in the healing process, and both synthesize and re-
absorb collagen. The newly formed tissue starts to mature, and the collagen fibers are increasingly orientated along the direction of force through the tendon. This phase of repair continues for some 8 weeks after the initial injury.
Final stability is acquired during the remodeling induced by the normal physiological use of the tendon. This further orientates the fibers into the direction of force.
In addition, cross linking between the collagen fibrils increases the tendon tensile strength. During the repair phase, the mechanically stronger Type I collagen is pro- duced in preference to Type III collagen, thus slightly altering the initial ratio of these fibers to increase the strength of the repair.
Despite intensive remodeling over the following months, complete regeneration of the tendon is never achieved. The tissue replacing the defect remains hyper- cellular. The diameter of the collagen fibrils is altered, favoring thinner fibrils with reduction in the biomechan- ical strength of the tendon.
In tendinopathic and ruptured tendons, there is a reduction in the proportion of Type I collagen, and a sig- nificant increase in the amount of Type III collagen [30], responsible for the reduced tensile strength of the new tissue due to a reduced number of crosslinks compared to Type I collagen [31]. Recurring microinjuries lead to the development of hypertrophied biologically inferior tissue replacing the intact tendon.
Cytokines and Modulation of Tendon Healing
Growth factors and other cytokines play a key role in the embryonic differentiation of tissue and in the healing of tissues [32]. Growth factors stimulate cell proliferation and chemotaxis and aid angiogenesis, influencing cell differentiation. They regulate cellular synthetic and secretory activity of components of extracellular matrix.
Finally, growth factors influence the process of healing.
In the normal flexor tendon of the dog, the levels of basic fibroblast growth factor (bFGF) are higher than the levels of platelet derived growth factor (PDGF). In injured tendons, the converse is true [33]. Under the influ- ence of PDGF, chemotaxis and the rate of proliferation of fibroblasts and collagen synthesis are increased [34].
Fibroblasts of the patellar tendon show increased prolif- eration in vitro after the administration of bFGF [35]. In addition, an angiogenic effect is evident [36]. During the embryogenesis of tendon, bone morphogenic proteins (BMP), especially BMP 12 and 13, cause increased expres- sion of elastin and collagen Type I. Also, BMP 12 exerts a positive effect on tendon healing [37].
The growth factors of the transforming growth factor beta superfamily induce an increase in mRNA expression of Type I collagen and fibronectin in cell culture experi- ments [38]. High expression of Type I collagen seems essential to achieve faster healing of tendons. Conse-
quently, there should be a shift from the initial produc- tion of collagen Type III to Type I early in the healing process. The aforementioned growth factors could poten- tially be used to influence the processes of regeneration of tendons therapeutically. However, it is unlikely that a single growth factor will give a positive result. The inter- action of many factors present in the right concentration at the right time will be necessary.
Operative Management of Tendinopathy
Each tendon has peculiarities in terms of clinical presen- tation, specific aspects of conservative and surgical man- agement, recovery etc. The discussion that follows will focus on the Achilles tendon, as it is the most studied and commonly encountered in clinical practice. Also, many of the technical and biological considerations applied to the Achilles tendon can be extrapolated to other tendons.
The natural history of Achilles tendinopathy is still unclear: 24%– 45.5% of the patients with Achilles tendinopathy fail to respond to conservative manage- ment and will undergo surgery [39,40]. In an 8-year lon- gitudinal study of conservative management of Achilles tendinopathy patients, 24 of the 83 patients (29%) were operated. Seventy patients (84%) had full recovery of their activity level. At 8 years, 78 patients (94%) were asymptomatic or had only mild pain with strenuous exer- cise. However, 34 patients (41%) started to suffer from Achilles tendinopathy in the initially uninvolved con- tralateral tendon [24,25].
Surgery is recommended after exhausting conservative methods of management, often tried for at least 6 months.
However, long-standing Achilles tendinopathy is associ- ated with poor postoperative results, with a greater rate of re-operation before reaching an acceptable outcome [26]. In general, surgical procedures can be broadly grouped in 4 categories, namely open tenotomy with removal of abnormal tissue without stripping the paratenon; open tenotomy with removal of abnormal tissue and stripping of the paratenon; open tenotomy with longitudinal tenotomy and removal of abnormal tissue with or without paratenon stripping; and percuta- neous longitudinal tenotomy [41– 47]. The technical objective of surgery is to excise fibrotic adhesions, remove degenerated nodules and make multiple longitu- dinal incisions in the tendon to detect and excise intra- tendinous lesions. The biological objective of surgery is to restore vascularity and possibly stimulate the remain- ing viable cells to initiate cell matrix response and heal- ing [41,43,48–50]. The reasons why multiple longitudinal tenotomies work are still unclear. Recent investigations show that procedure triggers neoangiogenesis in the
tendon, with increased blood flow [51]. This would result in improved nutrition and a more favorable environment for healing.
At surgery, the crural fascia is released on both sides of the tendon. Adhesions around the tendon are then trimmed, the hypertrophied paratenon is excised [39]. In addition, longitudinal splits are made in the tendon to identify the abnormal tendon tissues and excise the areas of degeneration. Reconstruction procedures may be required if large lesions are excised [52].
Open Operative Technique
We perform the operation on an outpatient day case basis. The patient is examined immediately pre-opera- tively to correctly identify and mark the area of maximum tenderness and swelling. We normally do not use a tourniquet but lift the end of the operating table 15 to 20 degrees [53]. The patient lies with the ankles resting on a sandbag or a pillow and the feet dependant over the end of the operating table. A longitudinal slightly curved incision is centered over the abnormal part of the tendon and placed medially, with the concave part toward the tendon. If a lateral approach is used, one should avoid the sural nerve and the short saphenous vein [54,55].
The paratenon and crural fascia are incised and dis- sected from the underlying tendon. If necessary, the tendon is freed from adhesions on the posterior, medial and lateral aspects. The paratenon should be excised obliquely, as transverse excision may produce a constric- tion ring that may require further surgery [56]. The fatty tissue anterior to the tendon should be left intact, as the mesotenon contained within it is an important source of vascular supply to the tendon. Areas of thickened, fibrotic and inflamed paratenon are excised. Inspection for areas lacking normal luster and careful palpation for thicken- ing, softening or defects will reveal local sections corre- sponding to areas of tendinosis within the tendon. These zones can be explored with longitudinal tenotomies. The pathology is identified by the change in texture and color of the tendon. The lesions are then excised, and the defect can either be sutured in a side-to-side fashion or left open: we normally leave it open. Occasionally, if exten- sive debridement is required, and a major defect in the tendon (>50%) is produced, a tendon transfer may be required [57]. In most cases, the lesions will be well local- ized, with normal tendon in between.
If used, the tourniquet can be deflated, and hemostasis achieved by diathermy. A below knee lightweight cast is applied with the foot plantigrade, and postoperative immobilization is continued for 2 weeks. Patients are encouraged to bear weight as soon as possible. Greater protection is recommended in patients needing tendon reconstruction. At 2 weeks, the cast is removed and stretching exercises are started. Sport specific training
is started at 3 months and competition is resumed at 6 months.
Complications of Open Surgery
It is remarkable how, for a condition which is relatively common, most studies did not report their assessment procedure, which makes it difficult to compare the results [58,59]. Most authors report excellent or good result in up to 85% of cases, and most articles reporting surgical success rates have over 70% of successful results [58,59].
Schepsis and Leach report good results in patients with paratendinitis and mucoid degeneration [45]. Kvist [13]
reports good and excellent results of both paratendinitis and tendinosis. However, this is not always observed in clinical practice [26]. In a recent systematic review of the published postoperative results of surgery for Achilles tendinopathy, we found an inverse relationship between reported success rates and the quality of the scientific methodology used in the study [58,59]. The most com- mon complication following operative management of Achilles tendinopathy is skin breakdown, but deep vein thrombosis and lesions to the sural nerve have been reported.
Outcome of Open Surgery
In the most comprehensive study to date, 432 consecutive patients were followed up longitudinally for 5 months after the surgery. If a complication arose, the patient was followed up clinically for at least 1 year. There were 46 (11%) complications in the 432 patients, and 14 patients with a complication had a re-operation. However, the majority of patients with a complication healed and returned to their pre-injury levels of activity [24].
The long-term effects of operative management are still not fully clarified. The relative underuse of the affected lower limb following surgery results in pro- longed calcaneal bone loss despite early weightbearing loading in patients surgically treated for chronic tendinopathy of the main body of the Achilles tendon.
The bone loss had not recovered 1 year postoperatively, but in a comparison group there were no significant side- to-side differences 39.5 months postoperatively [60].
Also, calf muscle strength deficit seen on the injured side preoperatively in this group of patients remains despite pain-free and active in sports or at recreational level 5 years after the operation. However, the percentage side- to-side difference is relatively low, and might not have any clinical relevance [61].
Peroneus Brevis Tendon Transfer
We use tendon transfer procedures when the tendino- pathic process has required debulking of at least 50% of the main body of the Achilles tendon. We normally use
the tendon of peroneus brevis for such procedure [62].
Other authors have used flexor hallucis longus [63].
Operative Technique of Peroneus Tendon Transfer A 10- to 12-cm longitudinal skin incision is made just medial to the medial border of the Achilles tendon and sharp dissection is carried out through the subcutaneous fat layer. A longitudinal slightly curved incision is cen- tered over the abnormal part of the tendon and placed medially, with the concave part toward the tendon (see above).
The paratenon and crural fascia are incised and dis- sected from the underlying tendon. If necessary, the tendon is freed from adhesions on the posterior, medial and lateral aspects. The paratenon should be excised obliquely, as transverse excision may produce a constric- tion ring that may require further surgery [56]. The fatty tissue anterior to the tendon should be left intact, as the mesotenon contained within it is an important source of vascular supply to the tendon. Through longitudinal teno- tomies, the pathology is identified. The lesions are then excised, and if the debridement involved 50% or more of the main body of the Achilles tendon, we proceed to perform a peroneus brevis tendon transfer. Through the base of the wound, the deep fascia overlying the deep flexor compartment and the compartment containing the peronei muscles can be seen. The internervous plane lies between peroneus brevis (supplied by the superficial per- oneal nerve) and the flexor hallucis longus (supplied by the tibial nerve). The peroneus brevis tendon can be iden- tified towards the medial side. The muscle belly of per- oneus brevis passes from the midline medially and under the tendon of peroneus longus to lie anterior to it and adjacent to the posterior aspect of the lateral malleolus.
The tendons of peroneus longus and brevis can be dis- tinguished from each other at this level by the fact that, although both tendinous in the distal third of the lower leg, peroneus brevis is muscular more distally than peroneus longus. The deep fascia overlying the peroneal tendons is incised and the peroneal tendons are mobilized.
Peroneus brevis passes around the posterior aspect of the lateral malleolus and above the peroneal trochlea to insert onto the styloid process of the base of the fifth metatarsal. The peroneal tendons are bound down both at the level of the lateral malleolus and at the level of the peroneal trochlea by the superior peroneal retinaculum and the inferior peroneal retinaculum, respectively.A 2.5- cm longitudinal incision is made over the base of the fifth metatarsal. The peroneus brevis tendon is identified, a stay suture is placed in the distal end of the peroneus brevis tendon, the tendon is detached from its insertion and mobilized proximally. The tendon is then delivered through the posteromedial wound using gentle continu-
ous traction as it is pulled through the inferior peroneal retinaculum. In this fashion, the tendon of peroneus brevis retains its blood supply from the intermuscular septum.
The peroneus brevis tendon is then weaved through the Achilles tendon starting from lateral to medial in a distal to proximal direction via coronal incisions medially and laterally in the Achilles tendon. The edges of the coronal incisions in the Achilles tendon are sutured to the peroneus brevis tendon to prevent progression of the incision that would lead to the peroneal tendon cutting out. The tendon is then passed through the Achilles tendon with the foot in physiological plantar flexion to maintain the correct tension. At times, the tendon of plantaris can be harvested to reinforce the reconstruction.
Postoperative Management
The limb is elevated on a Braun frame and, following review by a physiotherapist, the patient is generally dis- charged the day following surgery. A full below knee cast is applied with the ankle in natural equinus and retained for 2 weeks until outpatient review. Patients are allowed to bear weight on tip toes of the operated leg as toler- ated, but are told to keep the leg elevated as much as pos- sible until seen in the clinic, when the cast is removed.
The lower limb is left free, and patients are encouraged to bear weight on the operated limb as soon as they felt comfortable, and to gradually progress to full weight- bearing. The patients are taught to perform gentle mobi- lization exercises of the ankle, isometric contraction of the gastroc-soleus complex, and gentle concentric con- traction of the calf muscles. Patients are encouraged to perform mobilization of the involved ankle several times per day. Patients are given an appointment 6 weeks from the operation, when they are referred for more intensive physiotherapy. They are allowed to begin gentle exercise such as swimming and cycling at 8 weeks following surgery.
Experimental Operative Procedures
Percutaneous Longitudinal Tenotomy
In patients with isolated Achilles tendinopathy with no paratendinous involvement and a well defined nodular lesion less that 2.5 cm long, we have used multiple percu- taneous longitudinal tenotomies when conservative man- agement has failed. An ultrasound (US) scan is used to confirm the precise location of the area of tendinopathy.
Patient are mobilized as soon as able [46,47,55]. If the multiple percutaneous tenotomies are performed in the absence of chronic paratendinopathy, the outcome is comparable to that of open procedures. In addition, the
procedure is simple and can be performed under local anesthesia without a tourniquet, but attention to details is necessary, as complications occur even in minimally invasive procedures.
In patients with diffuse or multinodular tendinopathy or with pantendinopathy, a formal surgical exploration with stripping of the paratenon and multiple longitudinal tenotomies may be preferable [47].
Operative Technique for Percutaneous Longitudinal Tenotomy
Patients are operated as day cases. The patient lies prone on the operating table with the feet protruding beyond the edge, and the ankles resting on a sandbag. A blood- less field is not necessary. The tendon is accurately palpated, and the area of maximum swelling and/or tenderness marked, and checked again by US scanning.
The skin and the subcutaneous tissues over the Achilles tendon are infiltrated with 10 to 15 mL of plain 1% lig- nocaine (Lignocaine Hydrochloride, Evans Medical Ltd, Leatherhead, England).
A number 11 surgical scalpel blade is inserted parallel to the long axis of the tendon fibers in the marked area(s) with the cutting edge pointing cranially. Keeping the blade still, a full passive ankle dorsi-flexion movement is produced. After reversing the position of the blade, a full passive ankle plantar-flexion movement is produced. A variable, but probably in the region of 2.8 cm long, area of tenolysis is thus obtained through a stab wound. The procedure is repeated 2 cm medial and proximally, medial and distally, lateral and proximally and lateral and dis- tally to the site of the first stab wound. The 5 wounds are closed with Steri-Strips, dressed with cotton swabs, and a few layers of cotton wool and a crepe bandage are applied.
Operative Technique of Ultrasound-Guided Percutaneous Longitudinal Tenotomy
Patients are operated as outpatients. The patient lies prone on the examination couch with the feet protruding beyond the edge, and the ankles resting on a sandbag. A bloodless field is not necessary. The tendon is accurately palpated, and the area of maximum swelling and/or ten- derness marked, and checked by US scanning. The skin is prepped with an antiseptic solution, and a sterile lon- gitudinal 7.5 MHz probe is used to image again the area of tendinopathy. Before infiltrating the skin and the subcutaneous tissues over the Achilles tendon with 10 ml of 1% lignocaine (Lignocaine Hydrochloride, Evans Medical Ltd, Leatherhead, England), 7 ml of 0.5% ligno- caine (Lignocaine Hydrochloride, Evans Medical Ltd, Leatherhead, England) are used to infiltrate the space
between the tendon and the paratenon, to try and distend the paratenon and break the adherences that may be present between the tendon and the paratenon.
Under US control, a number 11 surgical scalpel blade (Swann-Morton, England) is inserted parallel to the long axis of the tendon fibers in the centre of the area of tendinopathy, as assessed by high resolution US imaging.
The cutting edge of the blade points caudally, and pene- trates the whole thickness of the tendon. Keeping the blade still, a full passive ankle plantar-flexion is produced.
The scalpel blade is then retracted to the surface of the tendon, and inclined 45 degrees on the sagittal axis, and the blade is inserted medially through the original teno- tomy. Keeping the blade still, a full passive ankle plantar- flexion is produced. The whole procedure is repeated inclining the blade 45° laterally to the original tenotomy, inserting it laterally through the original tenotomy.
Keeping the blade still, a full passive ankle plantar-flexion is produced. The blade is then partially retracted to the posterior surface of the Achilles tendon, reversed 180 degrees, so that its cutting edge now points caudally, and the whole procedure repeated, dorsiflexing the ankle pas- sively. Preliminary cadaveric studies showed that a teno- tomy 2.8 cm long on average is thus obtained through a stab wound in the main body of the tendon [55]. A Steri- Strip (3M United Kingdom PLC, Bracknell, Berkshire, England) can be applied on the stab wound, or the stab wound can be left open [64]. The wound is dressed with cotton swabs, and a few layers of cotton wool and a crepe bandage are applied.
Postoperative Management
On admission, patients are taught to perform isometric contractions of their triceps surae [65]. Patients are instructed to perform the isometric strength training at 3 different angles, namely at maximum dorsi-flexion, maximum plantar flexion and at a point midway between the two.
The foot is kept elevated on the first postoperative day, and oral analgesia is administered as requested for pain control. Early active dorsi- and plantar flexion of the ankle are encouraged [66]. Patient are allowed to walk using elbow crutches weight-bearing as able. Full weight- bearing is encouraged after the second postoperative day, when the bandage is reduced to a simple adhesive plaster over the wounds and an elasticated compressive sock, to be removed at night. Stationary bicycling, and iso- metric, concentric and eccentric strengthening of the calf muscles is started at that stage under physiotherapist guidance.
Gentle jogging on an elastic trampoline is permitted after 2 weeks, when the sock and the adhesive plaster are removed. Swimming and water running are encouraged
from the second week. Gentle running is started 4 to 6 weeks after the procedure, and mileage gradually increased. Hill workouts or interval-training are allowed after a further 6 weeks, when return to normal training is allowed.
Ultrasound-guided percutaneous longitudinal teno- tomy is simple, requires only local anesthesia, is per- formed without a tourniquet, and allowed the return to high sporting levels of the majority of the athletes with a tendinopathy of the main body of the tendon. Early post- operative mobilization probably prevents the formation of adhesions, and a single skin wound most likely limits morbidity. In most instances, the affected tendon remained thicker than the healthy one, and the clinical results are comparable with those reported using more extensive procedures [15,16].
Arthroscopic Procedures
Arthroscopy is now in the armamentarium of orthopedic surgeon for the routine management of rotator cuff disorders [67].
“Tendoscopy” has been used by several authors to approach in a minimally invasive fashion a variety of tendinopathic tendons, including tibialis anterior [68], Achilles tendon, where the surgical endoscopic technique includes peritenon release and debridement, and longi- tudinal tenotomies [69,70]; patellar tendon [71]; peroneal tendons [72]; tibialis posterior [73]; tennis elbow [74] with encouraging results. Some authors have used arthro- scopic techniques for biceps tenodeses [75]. Given the limited field of vision that there techniques involve, care must be taken to avoid iatrogenic lesion of the surrounding tissues.
To our knowledge, only one study has compared arthroscopic techniques with classical open techniques [76]. In that study, which focussed on the patellar tendon, arthroscopic patellar tenotomy was as successful as the traditional open procedure, and both procedures pro- vided virtually all subjects with symptomatic benefit.
However, only about half the subjects who underwent either open or arthroscopic patellar tenotomy were able to compete at their former sporting level at follow-up.
Muscle Transfer to the Body of the Tendon
Longitudinal tenotomies increase the blood supply of the degenerated area [51]. Recently, in a rabbit model, following longitudinal tenotomy we have performed a soleus pedicle graft within the operated tendon, and shown that the transplanted muscle was viable and had integrated well within the tendon tissue 3 months after
the transplant, without transforming into connective tissue. Hypervascularization of the graft tissue, probably due to the operation, was also observed, together with neoangiogenesis up to 3 months after the operation [77].
A Difficult Problem: Calcific Insertional Tendinopathy
Some patients may present with tendinopathy at the insertion of the Achilles tendon on the calcaneus [78].
Occasionally, a digitation of bone from the calcaneus to the Achilles tendon is radiographically evident, and is associated with retrocalcaneal bursitis [79]. In these patients, following failure of conservative manage- ment [18,80], surgery includes bursectomy, excision of the diseased tendon, and resection of the calcific deposit [81,82].
Patients undergo surgery as day cases. With the patient prone under general anesthesia with a thigh tourniquet inflated to 250 mmHg to provide hemostasis after the limb had been exsanguinated, the Achilles tendon is exposed through a longitudinal incision 1 cm medial to the medial border of the tendon. The incision is extended from the lower one-third of the tendon to up to 2 cm distal to its calcaneal insertion. At times, it is necessary to curve the incision transversely and laterally in a hockey stick fashion. Sharp dissection is continued to the paratenon, which is dissected from the tendon and excised, taking care to preserve the anterior fat in Kager’s triangle and not to injure the mesotenon. The retrocal- caneal bursa is excised. The tendon is inspected for areas which have lost their normal shining appearance, and pal- pated for areas of softening or thickening. The areas which have lost their normal shining appearance, and the areas which are softer or thicker areas are explored via 1 to 3 longitudinal tenotomies, and areas of degeneration are excised. The longitudinal tenotomies are not repaired [8]. The area of calcific tendinopathy is identified, and its proximal, medial and lateral edges defined using the tip of a syringe needle. The calcific area is then exposed start- ing from its proximal and medial aspect. If necessary, the Achilles tendon surrounding the area of calcific tendinopathy is detached by sharp dissection. The area of calcific tendinopathy is excised from the calcaneus. The area of hyaline cartilage at the postero-superior corner of the calcaneus is excised using an osteotome, and, if needed, its base paired off with bone nibblers. The tendon is re-inserted in the calcaneus using 2 to 5 bone anchors [Mitek GII, Ethicon Ltd., Edinburgh, Scotland). Three bone anchors are used if 50% to 75% of the Achilles tendon had been dis-inserted. Four bone anchors are used if 75% or more of the Achilles tendon had been dis-
inserted, and 5 bone anchors are used if the Achilles tendon has been totally dis-inserted. The Achilles tendon is advanced in a proximal to distal fashion, and reinserted in the calcaneum. A tendon augmentation or a tendon transfer is rarely necessary.
After release of the tourniquet, hemostasis is achieved by diathermy. The wound was closed in layers using absorbable sutures.
Postoperative Management
The skin wound is dressed with gauze, and sterile plaster wool applied. A synthetic below knee cast with the ankle plantigrade is applied. Patients are discharged the day of surgery within 8 hours of the operation. Patients are asked to mobilize with crutches under the guidance of a physiotherapist in the immediate postoperative period.
Patients are allowed to bear weight on the operated leg as tolerated, but were told to keep the leg elevated as much as possible for the first 2 postoperative weeks. The cast is removed 2 weeks after the operation. A synthetic anterior below knee slab is applied, with the ankle in neutral. The synthetic slab is secured to the leg with 3 or 4 removable Velcro (Velcro USA Inc., Manchester, NH, USA) straps for 4 weeks. The patients are encouraged to continue to bear weight on the operated limb, and to gradually progress to full weightbearing, if they are not already doing so. The patients are taught gentle mobilization exercises of the ankle, isometric contraction of the gastroc-soleus complex, and gentle concentric contraction of the calf muscles. Patients are encouraged to perform mobilization of the involved ankle several times per day after unstrapping of the relevant Velcro strap(s). The anterior slab is removed 6 weeks from the operation.
Stationary cycling and swimming was recommended from the second week after removal of the cast. We allow return to gentle training 6 weeks after removal of the cast. Gradual progression to full sports activity at 20 to 24 weeks from the operation is planned according to the patients’ progress. Resumption of competition depends on the patients’ plans, but we do not recommended before 6 months after surgery.
Methods of Evaluation
Several quantitative tests of ankle function [83] have been used to measure outcome in Achilles tendinopathy.
However, condition-specific numerical scales generally have greater sensitivity and specificity than do general- purpose scales [84]. A specific scale for patients with patellar tendinopathy [83] has recently been published, and we have recently devised a self-administered ques-
tionnaire-based instrument to measure the severity of Achilles tendinopathy, the VISA-A [84]. There is a need for a quantitative index of pain and function in patients with Achilles tendinopathy. The VISA-A questionnaire appears a valid, reliable and easy-to-administer measure of the severity of Achilles tendinopathy, and seems suitable for both clinical rating and quantitative research.
Conclusions
Surgery for chronic overuse tendon conditions, even when successful, does not reconstitute a normal tendon.
Mostly, the result is functionally satisfactory despite mor- phological differences and biomechanical weakness com- pared to a normal tendon. The therapeutic use of growth factors by gene transfer, it seems, may produce a tendon which is biologically, biomechanically, biochemically, and physiologically more “normal.”
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