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Hamstring avulsion injuries
Hamstring Avulsion Injuries Angelo J. Colosimo, MD,* Heather M. Wyatt, PAC,† Kristy A. Frank, ATC/L,† and Robert E. Mangine, PT, MEd, ATC/L‡ In the athletic population, injuries to the hamstring muscle comprise one of the most common injuries reported in the literature. Because of the increased size, stress, and explosive ability of athletes today, these injuries have become relatively common. Over the last few years, complete hamstring avulsions from the ischial insertion have received greater attention because of advanced diagnostic capabilities. Conservative treatment for these pathologies may result in long-term dysfunction, secondary to the high-powered nature of the athlete today. When ineffective, nonoperative treatment results in continued complaints of pain, loss of explosive power, and an inability to return to previous level of function. It has been our experience that immediate and primary repair of the proximal hamstring avulsion from the ischial insertion yields a positive functional result with efficient return to activity. The mechanical force associated with this injury is forced hip flexion, with eccentric contraction of the hamstrings. The athlete perceives a “popping” or “snapping” sensation in the posterior buttocks, accompanied by immediate pain and asymmetrical gait. Diagnosis is based on the subjective history, which results in a high clinical suspicion. The clinical examination is consistent with a palpable defect in the hamstring insertion; ecchymosis over the posterior hamstring and definitive diagnosis is based on magnetic resonance imaging evaluation. Although traditional teachings assert that conservative treatment of tendon injuries is the standard, proximal hamstring tendon avulsion requires a completely different algorithm. Our current and more aggressive approach incorporates a surgical procedure, which leads to the best possible outcome for these athletes. Oper Tech Sports Med 13:80-88 © 2005 Elsevier Inc. All rights reserved. KEYWORDS hamstring, avulsion fracture, ischial tuberosity avulsion, hip
H
amstring muscle injuries are among the most frequently encountered injuries and result in long-term dysfunction experienced at all levels of athletic participation. Less frequent injuries resulting in greater long-term debilitation are complete proximal hamstring avulsions. Hamstring injuries stem from its design as a bijoint muscle that permits extreme excursion of range of motion, with high-tension forces.1,2 As with all musculoskeletal injuries, the healing response follows the staged progression of inflammation, fibroblast formation, and eventual collagen reorganization. A rehabilitative protocol in a majority of cases results in the athlete’s progressive return to participation. Although hamstring muscle tears in athletes are common, they can be complex and significant injuries. Typically, they *Department of Orthopaedic Surgery, University of Cincinnati, Cincinnati, OH. †University Orthopaedic Consultants of Cincinnati, Inc, Cincinnati, OH. ‡NovaCare Rehabilitation, Cincinnati, OH. Address reprint requests to Angelo J. Colosimo, MD, 231 Albert Sabin Way Cincinnati, OH 45267-0212.
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are partial tears that occur at the myotendinous junction; these are easily diagnosed based on mechanism of injury, localized pain, and resultant loss of function.3,4 Nonoperative treatment usually results in a normal functional outcome. Heiser and coworkers5 completed a retrospective review of 46 primary hamstring muscle injuries in collegiate football players, observing an average recovery period of 2 weeks before full return to activity. Preventive strengthening and flexibility training has a demonstrated influence on the incidence of injury to the hamstring muscles in addition to decreasing the likelihood of recurrence. Complete proximal hamstring tendon avulsions can result in a higher level of incapacitation. There is, however, a considerable delay in diagnosis, indicating that the severity of the injury is underappreciated. Diagnosis should be based on a complete history, including mechanism of injury, subjective complaints, clinical examination, and radiographic assessment. Accurate diagnosis of this injury requires a high level of suspicion and a keen level of awareness. Sallay and coworkers6 documented 12 proximal hamstring tendon injuries in a group of water skiers. All of the injuries occurred with a
Hamstring avulsion injuries
81 sistent with other studies that suggest an improperly assessed and rehabilitated athlete is at high risk of repeated injury after an early return to activities.5,11 We believe that in the recreational and active athletic population, a rupture of the hamstring tendons off of the ischial insertion occurs more than previously thought. Currently, we recommend full evaluation of these injuries so that appropriate intervention can be applied. Our protocol with complete ruptures prescribes an anatomic repair to the ischium to enhance the patient’s prognosis for functional recovery and normal mechanics.
Anatomy and Physiology
Figure 1 Conjoined hamstring tendon tear off of ischium.
common mechanism of forced hip flexion while maintaining knee extension. This mechanism, in conjunction with an eccentric hamstring contraction, resulted in avulsion of the hamstring tendon near its insertion. Ruptures usually involve the long head of the biceps femoris and occur at the myotendinous junction.7-9 When a complete rupture of the ischial origin of the hamstring muscle occurs in an athlete, poor functional outcomes have been reported. Typically, the hamstring pulls off the ischium with all 3 tendons as 1 mass, the semimembranosus detaching first (Fig. 1). In our experience, these athletes often experience persistent pain, inability to sit, weakness in full flexion, loss of speed and explosive power, repeat hamstring injury, and an inability to return to their previous level of function. There are published reports of neurologic involvement with avulsion of the proximal hamstring tendon. In a case report, Street and coworkers10 attributed the sequela of neurologic symptoms and eventual delayed foot drop to a complete proximal hamstring avulsion. This was theorized to have occurred secondary to probable sciatic nerve involvement. Sallay and coworkers6 have shown that 5 of 6 patients with complete ruptures reported poor leg control and were significantly limited and unable to run or participate in sports requiring agility. Their study recorded a low return rate to sports among nonoperatively treated patients with complete proximal hamstring tendon ruptures. In addition, this is con-
The hamstring group is composed of the biceps femoris, semimembranosus, and semitendinosus muscles and spans the posterior thigh. With the exception of the short head of the biceps femoris, all 3 muscles cross the hip and knee joints. The ischial tuberosity serves as the origin for the hamstring group on the pelvis, and their tibial insertions follow a specific pattern below the knee (Fig. 2). The short head of the biceps, however, originates from the linea aspera and posterior femur. Both the semitendinosus and the long head of the biceps femoris muscles arise from the lower and medial impression on the tuberosity of the ischium. The semitendinosus tendon forms the medial border of the popliteal space at the knee, curving around the medial condyle of the tibia and inserting as part of the pes anserine into the proximal border of the tibia’s medial surface. The semimembranosus muscle originates at the upper and outer impression on the tuberosity of the ischium. The belly of the muscle begins about halfway down the thigh, and the insertion at the knee is rather complex. It ends, mainly, in the horizontal groove on the posteromedial aspect of the medial condyle of the tibia, but a prominent reflection from here forms the oblique popliteal ligament of the knee joint. Other fibers extend from the tendon to the medial collateral ligament and onto the fascia of the popliteus muscle. The semimembranosus is a critical dynamic stabilizer, allowing the knee to withstand forces applied during functional activities. The biceps femoris muscle is a combination of one preaxial muscle, the long head, and 1 postaxial muscle, the short head. The long head arises in combination with the semitendinosus muscle from the lower and medial impression of the ischial tuberosity and the lower part of the sacrotuberal ligament. The short head originates on the lateral edge of the linea aspera of the femur, the proximal two thirds of the supracondylar line, and the lateral intermuscular septum. The muscle fibers of the short head join the tendon of the long head to form the thick round tendon that composes the lateral margin of the popliteal fossa. As it crosses at the knee, the tendon divides to surround the lateral collateral ligament and ends on the lateral aspect of the head of the fibula, the lateral condyle of the tibia, and in the deep fascia of the lateral aspect of the leg. The semitendinosus, semimembranosus, and long head of the biceps femoris are all innervated from the tibial branch of
Colosimo et al
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Figure 2 Hamstring muscle group and its insertion on ischium.
the sciatic nerve. The peroneal branch of the sciatic nerve innervates the short head of the biceps. The fourth and fifth lumbar and the first, second, and third sacral nerves supply the muscles of this region. The action of the hamstring muscles is multitasked because of its bijoint design. At the knee, its primary job is flexion and secondarily it is tibial rotation. Because of this, stress is placed on those muscles dependent on the position of the hip and knee joints. Because of the high stress position with function, along with its ability to maintain posture and control of the pelvis during ambulation, almost any portion of the muscle has the potential for injury.
Mechanism of Injury Avulsion of multiple tendons can result in complex injuries in the pelvic region, especially in the pediatric age group with open growth plates. Hamstring strains or tears from the ischium are usually acute and dramatic. Adolescents are more likely to have a portion of the bone avulsed from the ischium, which can be detected radiographically, secondary to the apophysis being a weak link in the bony structure of this age group.12,13 Avulsions of the hamstring originating from the ischial tuberosity in adults, by contrast, are not as common and usually do not present
radiographically with bony involvement. Steinbruck14 reported that less than 4% of athletic injuries are complete tendon or muscle ruptures. Orava and Ala-Ketola15 reported only 1 of 34 consecutive avulsion fractures involved the ischial tuberosity. These injuries are described as extremely disabling and require a long period of rest and rehabilitation. Although conservative management is often recommended, cases in which bony fragments are displaced greater than 3 cm in the adolescent age group should be repaired. Hamstring muscle strains commonly result from a wide variety of sporting activities, particularly those requiring rapid acceleration and deceleration. Avulsion injuries can occur from a forced hip flexion with simultaneous knee extension.6,16-18 Eccentric loading of the muscle can produce forces sufficient to rupture the hamstrings.7,19 The force generated is concentrated at the myotendinous junction, in which the majority of these injuries occur.1,7,19 Whether dealing with the pediatric age group and bony avulsion or the adult population, the mechanism remains the same.
Diagnosis Hamstring tendon avulsions are rare injuries and are often difficult to distinguish from simple muscle strains (Table 1).
Table 1 Grading of Hamstring Muscle Strains Degree
Musculotendinous Unit
Pain
Swelling
Strength
Motion
First Second Third
No disruption Partial disruption Complete disruption
Mild Moderate Severe
ⴙ ⴙⴙ ⴙⴙⴙ
0 ⴚ ⴚⴚ
0 ⴚ ⴚⴚ
Hamstring avulsion injuries
83 Table 2 Hamstring Conservative Treatment Protocol
Figure 3 MRI (coronal, T1-weighted image) revealing complete hamstring avulsion with evident hematoma.
Typically, the history consists of a sudden onset of pain in the medial posterior pelvis, gluteal, or thigh region while the muscle is undergoing a voluntary or involuntary eccentric contraction with hip flexion and knee extension. Patients may also report feeling or hearing a “pop” at the time of injury and have difficulty with sitting. Normally, the patient will report weak knee flexion, but true weakness may be difficult to distinguish from painful guarding with an acute injury. Oftentimes, secondary muscle spasm may influence the patient’s subjective complaints. They may also have a feeling of
Figure 4 MRI (axial, T1-weighted image) revealing complete hamstring avulsion with evident hematoma.
Phase I Use of assistive devices Cryrotherapy Compression Elevation Electrical currents Phase II Cryrotherapy Stretch hamstrings, quadriceps, and hip flexors NSAIDs (nonsteroidal anti-inflammatory drugs) Electrical modalities for inflammation control Isometrics for hamstrings in a painfree ROM Core stabilization Isotonics, short arc eccentric Closed chain training Phase III Cryrotherapy Stretch hamstrings, quadriceps, and hip flexors NSAIDs Electrical modalities for inflammation control Isotonics, short arc eccentric Closed chain, high performance training Phase IV Cryrotherapy Stretch Running, gradually increasing in distance and time Sport-specific training Phase V Return to activity
instability, with a chief complaint of giving way while descending stairs. A palpable defect on the tendon, just distal to the ischial tuberosity, is common, especially with the complete avulsion of a portion of the ischial tuberosity. In addition, a loss of normal contour of the posterior thigh and ecchymosis may be noticeable when compared with the unaffected leg.17 The senior author has established a position of testing in which he terms a positive finding to be the “Garrett sign.” One should look for this “Garrett sign” by testing for decreased strength with resisted knee flexion and passive knee extension with the hip flexed at 90°. Timely diagnosis and treatment of ischial tuberosity avulsions are essential, secondary to the residual loss of power, excessive scarring in the avulsion area, and potential for muscular retraction.20 Patients develop chronic complaints of pain in the lower extremity, weakness, and cramping with walking and running.2,10,21 These patients also describe a loss of proprioception to the lower extremity and poor leg control, especially walking downhill on uneven surfaces, and explosive power.2,10 During extension of the knee in the swing phase, the hamstring muscles function eccentrically to decelerate the forward progression of the tibia.22 Timing of surgical intervention is a critical factor of tendon/muscle retraction. In multiple studies, cases of hamstring avulsions treated acutely with surgical intervention within 6 to 10 weeks of the injury yielded good results. Attempts to repair chronic avulsions
84
Figure 5 S-shaped incision centered in gluteal crease used for surgical procedure.
Colosimo et al process results in a positive outcome in most, its success in complete structural disruption is questionable. At the other end of the spectrum is the now well-described avulsion pathology of the hamstrings, which requires 3 to 4 months for complete functional return if nonsurgical intervention is elected. Initially, these injuries are treated with rest, icing, compression, analgesic medications, and protective weight bearing. A short period of immobilization is beneficial in limiting the extent of connective tissue proliferation, thus decreasing the occurrence and the amount of scar formation. In addition to being an analgesic, ice has been shown to limit inflammation and edema and slow metabolism. Compression wraps assist in controlling edema and limit the inflammatory response. Elevation is beneficial in controlling the vascular response. Crutches are recommended to allow the patient to ambulate without excessive pain or stresses on the injured site; they also facilitate normal gait patterns. Once acute symptoms abate, active exercise can be implemented. Initially, the resistance should be submaximal, using straight-leg raises and range of motion exercises. Isolated knee flexion exercises are slowly initiated using eccentric resistance at first and advancing to concentric loading.
after 12 weeks resulted in poor functional outcome, secondary to muscle/tendon retraction.1,6,16-18,21,23,24 In determining the extent of the injury, radiographic evaluation is helpful in all populations but especially in the pediatric age group. Ultrasonography and computer tomography (CT) scans have also proven valuable in evaluating these types of injuries. Positive findings on CT scans show the region of injury as an area of low density, associated with the presence of inflammation and edema or bleeding. CT scans, for diagnostic purposes of ischial tuberosity avulsions, are seemingly more useful in the subacute phase, approximately 1 to 3 weeks after the injury.25 Differential diagnosis for hamstring avulsions is critical, as the timing for surgical correction is best performed in the acute post injury phase. To facilitate this, magnetic resonance imaging (MRI) has evolved as the technique of choice due to enhanced visualization capability in evaluating the tendon during all phases of healing.1,23,25,26 MRI is also better at evaluating the location, extent, and severity of the injury, facilitating the correct diagnosis and rehabilitation for the patient (Figs 3 and 4). The amount of tendon retraction and the tendon edge morphology are important elements for preoperative assessment. Koulouris and Connell reported on the sensitivity and accuracy of MRI in verifying avulsion occurrence correctly in 16 of 16 patients compared with ultrasonography, which only identified 7 of 12.27
Treatment Standard intervention of partial muscle/tendon pathology incorporates a conservative program of stretching, use of nonsteroidal medication, modalities to control inflammation and pain, and strengthening (Table 2). Although this
Figure 6 S-shaped incision marked on patient showing ecchymosis from injury.
Hamstring avulsion injuries
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Figure 8 Fluoro-image after corrective procedure has been completed.
Figure 7 Hamstring repair technique using suture anchors.
Closed chain training is also incorporated into the program with advancement to full activity in 6 months. Surgical repair is indicated for either failed conservative treatment or for displacement of the bone greater than 2.5 cm.1,24,28-30 Advancement for advocating surgical repair has evolved because of recent studies reporting the persistent weakness in patients treated conservatively.1,20 Sallay and coworkers6 described acute repair of hamstring avulsions as a technically feasible procedure with good results. Moreover, they warned that delay in the repair increases the risk of poor results, secondary to chronic fibrosis, retraction, and muscle atrophy. Our experience with surgical indications, although similar, is also currently evolving. They include a positive “Garrett sign,” definitive MRI documentation, level of occupation or athletic participation, and failure of conservative treatment.
is taken not to place undue tension on the sciatic nerve, which is protected by retractors. Subsequently, the gluteus maximus is freed circumferentially and later retracted superiorly. Through this muscle, we can usually palpate the hamstring tendon avulsion, as the scar tissue is balled up and retracted from its original attachment site. The fascia over the hamstring is incised longitudinally, exposing the hematoma as well as the torn ends of the hamstring. The ischium is palpated, and the ischial tuberosity is then exposed. Using a bovie and a periosteal elevator, the periosteum is elevated from the ischium and the bone freshened. Two to 4 suture anchors with double strands are inserted into the ischium and can then be applied to the hamstring tendons; they are separated and tagged for later use.
Surgical Procedure The surgical procedure places the patient in a prone position with the knee flexed. The hamstring muscles are palpated, and a transverse S-type incision, made in the gluteal crease (Figs. 5 and 6), is carried down through the skin and subcutaneous tissues. Surgical dissection continues through the fascia of the inferior border of the gluteus maximus and exposes the gluteus maximus muscle. After it is identified, care
Figure 9 Radiograph after corrective procedure has been completed.
Colosimo et al
86 Table 3 Hamstring Repair Rehabilitation Protocol Phase I (week 1 to 4) TTWB approximately 10–14 days 25% WB at 14 days and increasing 25% per week until off crutches at week 5 PROM as tolerated, starting in week 2, with hip and knee ROM Initiate gentle AROM around week 3 or 4 Discontinue brace post-op around day 21 to 28 Phase II (week 4 to 8) FWB is permitted if the patient demonstrates normal gait patterns Aquatic walking and ROM Closed chain emphasis with limited ROM Isotonics in limited range of motion, avoid terminal range of extension PROM knee extension and hip flexion Initiate core pelvic strength training Phase III (week 8 to 12) Progress isotonic strength training Advanced dynamic training Concentrate on core pelvic training Strength evaluation at 10 weeks-isometric mode only at 60° of knee flexion Phase IV (week 10 to 24) Begin dry land jogging/running Full isokinetic evaluation at 60°, 120°, and 180°/s, bilateral comparison Functional hop testing Sport specific activities Return to sporting activities
maintain this position until the initial visit to the physician’s office.
Postoperative Protocol Review of the current literature for postsurgical management of avulsions to the proximal hamstring has limited documentation providing a standard pathway. Klingele and coworkers22 recommended a period of limited range of motion and weight bearing but no specific exercise pathway or functional progression to full return to activity. Clanton and Coupe,1 in 1998, recommended a specific rehabilitation protocol for hamstring injuries in athletes, but this is a nonsurgical conservative approach with no mention of surgical pathway. The literature, therefore, lacks a pathway that minimizes risk of complication and provides insight to a safe exercise regime. The protocol we currently recommend is based on our experience in 9 consecutive cases over a 2-year period (Table 3). The pathway is designed to reestablish range of motion of both the hip and knee, regain proximal limb strength, facilitate a gradual relengthening of the hamstring, and progress function without repair disruption. The program is titrated over a 3- to 4-month period until resumption of function, based on achieving objective return to normal. In the immediate postsurgical period of 4 weeks, the patient is placed in a bijoint brace, which restricts hip and pelvic
Abbreviations: TTWB, toe-touch weight bearing; WB, weight bearing; ROM, range of motion; PROM, passive range of motion; AROM, active range of motion; FWB, full weight bearing.
Next, attention is turned to the hamstring avulsion. The mass of tendons is identified. They are brought together using a no. 5 Tycron stitch for temporary purposes. Once this is established, both the anterior and posterior ends of the hamstring musculature are freed from the soft tissue and scar tissue until they can be freely pulled to the level of the ischial tuberosity (Figs. 7-9). Once this is ensured, the suture anchors of no. 2 ethibond are then subsequently placed in Kessler-type (horizontal mattress type fashion) stitches through the proximal end of the hamstring muscles to secure the remainder of the hamstring tendon. It is then pulled forward to the ischium using the pulling stitch, and the sutures are subsequently tied in sequential fashion. This secures a very strong reattachment of the hamstring back to the ischial tuberosity, shown with flexion and extension of the knee. The sutures are tied with the knee flexed approximately to 30° and the hip in approximately 20° of extension. The repair does allow the knee to become completely straight; it is then brought back to 30° and held there for the remainder of the procedure. After this, the wounds are copiously irrigated and suctioned dry, and then the incision is closed. The patient postoperatively is placed in a brace with the hips in approximately 20° to 25° of extension and instructed to
Figure 10 Brace used postoperatively to prevent forward hip flexion (front view).
Hamstring avulsion injuries
87 single-leg balance, and proximal stabilization utilizing a coretraining program are keys to establishing normalized patterns of movement. Aerobic reconditioning must be undertaken in a low-load environment with advancement in time, which is as critical as stress application. Early initiation of retro training or backward ambulation in a pool, treadmill, or Stairmaster is beneficial to regain coordination and balance control.
Return to Activity/Play
Figure 11 Brace used postoperatively to prevent forward hip flexion (side view).
mobility. The brace is custom fabricated and maintains the hip in a neutral 0° position; maintaining the hip in this position limits stress at the reattachment site (Figs. 10 and 11). Also during this time period, the patient is restricted to toetouch non–weight-bearing gait pattern by using assistive devices such as crutches or a walker. The patient starts to come out of the brace after the first week for passive range of motion at the knee, while the hip remains in a nontensioned position. Starting at the fourth postoperative week, the brace is discontinued, and range of motion is reestablished, progressing through nonpainful ranges. Patients often are able to achieve 45° of hip flexion by this point. A full stretching program is only permitted after 6 weeks to gradually gain normal length to the hamstring muscle. Also, in the early phase, soft-tissue mobilization at both the insertion site and along the upper length of the hamstring muscle may be helpful in regaining motion and reducing scar development and pain. Toe touch weight bearing is initially permitted, and, after the second postoperative week, progression is made to partial weight bearing. The patient is then advanced an additional 25% of their body weight per week thereafter. Progression is made to 1 crutch at 5 weeks and the crutches are discontinued at the end of 5 weeks. For this progression to occur, advancement of a closed chain training program is recommended as well as reestablishing proprioception control of the limb. Inclusive exercises consisting of squats, leg press,
Return to recreational or competitive sports is recommended at a 4- to 5-month time period. Functional progression is based on sports-specific activity and emphasis on hamstring stretching before and after activity. Evaluation for return to sports involves both isokinetic dynamometer and functional testing. Isokinetic evaluation is done at 60°, 120°, and 180° per second velocity, with bilateral comparison recommended. Testing is done both at the knee and hip and bilateral comparisons are recommended to be within 15% of normal at slow and fast speeds. Furthermore, evaluation of the hamstring to quadriceps ratio should be 50% to 60% in the affected extremity at 60° per second, and the strength of the injured limb should be at least 85% of the opposite limb. Other criteria include equal restoration of flexibility, endurance, and single-limb position testing. Also validated in the literature is clinical evaluation by hop testing. The 2 tests we find most beneficial are the single-leg hop for distance and the single leg hop for time. Again, 85% symmetry is required for return to function. Functional evaluation, such as on-field testing, is critical and must be performed without symptoms before return to full activity.
Complications After open reduction and internal fixation of an ischial tuberosity fragment, the primary concern is fragment loosening. If fixation security is compromised, reattachment may be needed. In our experience, this has occurred 1 time, secondary to patient noncompliance in the acute phase of rehabilitation. On reattachment and proper progression through the pathway, the patient resumed full activity without complaints. As in all surgical procedures, other complications include infection, loss of motion, and chronic pain patterns, which can influence the rehabilitation period. We have not experienced this in our population, and other authors have not addressed this.
Conclusions Avulsion of the adult hamstring origin is an uncommon injury that occurs in less than 4% of all hamstring injuries.14 A comprehensive evaluation with complete physical examination, along with radiographic evaluation and the use of MRI, is essential for timely diagnosis. Complete ischial tubercle avulsion can compromise hamstring function. This has resulted in a change of treatment approach, necessitating surgical intervention. This aggressive approach is supported by
88 the literature for reattachment of the tendon to the pelvis in the acute phase of injury. Our experience, as with others, has shown better outcome results with surgical intervention compared with conservative treatment. Nonoperative treatment may result in weakness that is poorly tolerated in active patients. Current literature supports the ability to return to a recreational level of athletics after surgical repair. A consensus exists for acute primary repair to restore hamstring function. However, questions remain concerning the results of a professional level athlete requiring explosive ability of the hamstring muscle group for “normal” athletic function.
References 1. Clanton T, Coupe K: Hamstring strains in athletes: Diagnosis and treatment. J Am Acad Orthop Surg 6:237-247, 1998 2. Worrell T: Factors associated with hamstring injuries: An approach to treatment and preventative measures. Sports Med 17:338-345, 1994 3. Garrett WE Jr: Muscle strain injuries: Clinical and basic aspects. Med Sci Sports Exerc 22:436-443, 1990 4. Garrett WE Jr, Rich FR, Nikolaou PK, et al: Computer tomography of hamstring muscle strains. Med Sci Sports Exerc 21:506-514, 1989 5. Heiser TM, Weber J, Sullivan G, et al: Prophylaxis and management of hamstring muscle injuries in intercollegiate football players. Am J Sports Med 12:368-370, 1984 6. Sallay P, Friedman R, Coogan P, et al: Hamstring muscle injuries among water skiers: Functional outcome and prevention. Am J Sports Med 24:130-136, 1996 7. Garrett W: Injuries to the muscle-tendon unit. Instr Course Lect 37: 275-282, 1988 8. DeSmet AA, Best TM: MR imaging of the distribution and location of acute hamstring injuries in athletes. Am J Roentgenol 174:393-399, 2000 9. Speer KP, Lohnes J, Garrett WE Jr: Radiographic imaging of muscle strain injury. Am J Sports Med 21:89-95, 1993 10. Street C, Burks R: Chronic complete hamstring avulsion causing drop foot: A case report. Am J Sports Med 28:574-576, 2000 11. Pomeranz SJ, Heidt RS: MR imaging in the prognostication of hamstring injury: Work in progress. Radiology 189:897-900, 1993 12. Gill DR, Clark WB: Avulsion of the ischial apophysis. Austr N Z J Surg 66:564-565, 1996
Colosimo et al 13. Wootton JR, Cross MJ, Holt KW: Avulsion of the ischial apophysis. The case for open reduction and internal fixation. J Bone Joint Surg 72B: 625-627, 1990 14. Steinbruck K: Epidemiologic von sportverlezungen: 15-Jahres-analyse einer sportmedizinischen ambulanz. Sportsverletz Sportsch 1:2-12, 1987 15. Orava S, Ala-Ketola L: Avulsion fractures in athletes. Br J Sports Med 11:65-71, 1977 16. Orava S, Kujala U: Rupture of the ischial origin of the hamstring muscles. Am J Sports Med 23:702-705, 1995 17. Ishikawa K, Kai K, Mizuta H: Avulsion of the hamstring muscles from ischial tuberosity. Clin Orthop 232:153-155, 1988 18. Kujala U, Orava S, Jarvinen M: Hamstring injuries: Current trends in treatment and prevention. Sports Med 23:397-404, 1997 19. Bassewitz H, Mount J, Shapiro M: Speed trap: Hamstring injuries in athletes. Biomechanics 5:16-22, 1998 20. Brewer B: Athletic injuries: Musculotendinous unit. Clin Orthop 23: 30-38, 1962 21. Cross M, Vandersluis R, Wood D: Surgical repair of chronic complete hamstring tendon rupture in the adult patient. Am J Orthop 26:785-788, 1998 22. Klingele KE, Sallay PI: Surgical repair of complete proximal hamstring tendon rupture. Am J Sports Med 30:742-747, 2002 23. Kurosawa H, Nakasita K, Nakasita H, et al: Complete avulsion of the hamstring tendons from the ischial tuberosity: A report of two cases sustained in judo. Br J Sports Med 30:72-74, 1996 24. Servant C, Jones C: Displaced avulsion of the ischial apophysis: A hamstring injury requiring internal fixation. Br J Sports Med 32:255-257, 1998 25. Blasier RB, Morawa LG: Complete rupture of the hamstring origin from a water skiing injury. Am J Sports Med 18:435-437, 1990 26. Brandser E, El-Khouri G, Kathol M, et al: Hamstring injuries: Radiographic: Conventional tomographic, CT, and MR imaging characteristics. Musculoskeletal Radiol 197:257-262, 1995 27. Koulouris G, Connell D: Evaluation of the hamstring muscle complex following acute injury. Skeletal Radiol 32:582-589, 2003 28. Kujala U, Orava S: Ischial apophysis injuries in athletes. Sports Med 16:290-294, 1993 29. Milch H: Ischial apophysiolysis: A new syndrome. Clin Orthop 2:184193, 1953 30. Takayanagi H, Watanaba H, Shinozaki T, et al: Overgrowth of the ischial tuberosity complicating femoral bone and muscle atrophy: Implications for a delayed complication of malunited apophyseal avulsion fracture. Am J Orthop 27:308-312, 1998
H
amstring muscle injuries are among the most frequently encountered injuries and result in long-term dysfunction experienced at all levels of athletic participation. Less frequent injuries resulting in greater long-term debilitation are complete proximal hamstring avulsions. Hamstring injuries stem from its design as a bijoint muscle that permits extreme excursion of range of motion, with high-tension forces.1,2 As with all musculoskeletal injuries, the healing response follows the staged progression of inflammation, fibroblast formation, and eventual collagen reorganization. A rehabilitative protocol in a majority of cases results in the athlete’s progressive return to participation. Although hamstring muscle tears in athletes are common, they can be complex and significant injuries. Typically, they *Department of Orthopaedic Surgery, University of Cincinnati, Cincinnati, OH. †University Orthopaedic Consultants of Cincinnati, Inc, Cincinnati, OH. ‡NovaCare Rehabilitation, Cincinnati, OH. Address reprint requests to Angelo J. Colosimo, MD, 231 Albert Sabin Way Cincinnati, OH 45267-0212.
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1060-1872/05/$-see front matter © 2005 Elsevier Inc. All rights reserved. doi:10.1053/j.otsm.2004.09.005
are partial tears that occur at the myotendinous junction; these are easily diagnosed based on mechanism of injury, localized pain, and resultant loss of function.3,4 Nonoperative treatment usually results in a normal functional outcome. Heiser and coworkers5 completed a retrospective review of 46 primary hamstring muscle injuries in collegiate football players, observing an average recovery period of 2 weeks before full return to activity. Preventive strengthening and flexibility training has a demonstrated influence on the incidence of injury to the hamstring muscles in addition to decreasing the likelihood of recurrence. Complete proximal hamstring tendon avulsions can result in a higher level of incapacitation. There is, however, a considerable delay in diagnosis, indicating that the severity of the injury is underappreciated. Diagnosis should be based on a complete history, including mechanism of injury, subjective complaints, clinical examination, and radiographic assessment. Accurate diagnosis of this injury requires a high level of suspicion and a keen level of awareness. Sallay and coworkers6 documented 12 proximal hamstring tendon injuries in a group of water skiers. All of the injuries occurred with a
Hamstring avulsion injuries
81 sistent with other studies that suggest an improperly assessed and rehabilitated athlete is at high risk of repeated injury after an early return to activities.5,11 We believe that in the recreational and active athletic population, a rupture of the hamstring tendons off of the ischial insertion occurs more than previously thought. Currently, we recommend full evaluation of these injuries so that appropriate intervention can be applied. Our protocol with complete ruptures prescribes an anatomic repair to the ischium to enhance the patient’s prognosis for functional recovery and normal mechanics.
Anatomy and Physiology
Figure 1 Conjoined hamstring tendon tear off of ischium.
common mechanism of forced hip flexion while maintaining knee extension. This mechanism, in conjunction with an eccentric hamstring contraction, resulted in avulsion of the hamstring tendon near its insertion. Ruptures usually involve the long head of the biceps femoris and occur at the myotendinous junction.7-9 When a complete rupture of the ischial origin of the hamstring muscle occurs in an athlete, poor functional outcomes have been reported. Typically, the hamstring pulls off the ischium with all 3 tendons as 1 mass, the semimembranosus detaching first (Fig. 1). In our experience, these athletes often experience persistent pain, inability to sit, weakness in full flexion, loss of speed and explosive power, repeat hamstring injury, and an inability to return to their previous level of function. There are published reports of neurologic involvement with avulsion of the proximal hamstring tendon. In a case report, Street and coworkers10 attributed the sequela of neurologic symptoms and eventual delayed foot drop to a complete proximal hamstring avulsion. This was theorized to have occurred secondary to probable sciatic nerve involvement. Sallay and coworkers6 have shown that 5 of 6 patients with complete ruptures reported poor leg control and were significantly limited and unable to run or participate in sports requiring agility. Their study recorded a low return rate to sports among nonoperatively treated patients with complete proximal hamstring tendon ruptures. In addition, this is con-
The hamstring group is composed of the biceps femoris, semimembranosus, and semitendinosus muscles and spans the posterior thigh. With the exception of the short head of the biceps femoris, all 3 muscles cross the hip and knee joints. The ischial tuberosity serves as the origin for the hamstring group on the pelvis, and their tibial insertions follow a specific pattern below the knee (Fig. 2). The short head of the biceps, however, originates from the linea aspera and posterior femur. Both the semitendinosus and the long head of the biceps femoris muscles arise from the lower and medial impression on the tuberosity of the ischium. The semitendinosus tendon forms the medial border of the popliteal space at the knee, curving around the medial condyle of the tibia and inserting as part of the pes anserine into the proximal border of the tibia’s medial surface. The semimembranosus muscle originates at the upper and outer impression on the tuberosity of the ischium. The belly of the muscle begins about halfway down the thigh, and the insertion at the knee is rather complex. It ends, mainly, in the horizontal groove on the posteromedial aspect of the medial condyle of the tibia, but a prominent reflection from here forms the oblique popliteal ligament of the knee joint. Other fibers extend from the tendon to the medial collateral ligament and onto the fascia of the popliteus muscle. The semimembranosus is a critical dynamic stabilizer, allowing the knee to withstand forces applied during functional activities. The biceps femoris muscle is a combination of one preaxial muscle, the long head, and 1 postaxial muscle, the short head. The long head arises in combination with the semitendinosus muscle from the lower and medial impression of the ischial tuberosity and the lower part of the sacrotuberal ligament. The short head originates on the lateral edge of the linea aspera of the femur, the proximal two thirds of the supracondylar line, and the lateral intermuscular septum. The muscle fibers of the short head join the tendon of the long head to form the thick round tendon that composes the lateral margin of the popliteal fossa. As it crosses at the knee, the tendon divides to surround the lateral collateral ligament and ends on the lateral aspect of the head of the fibula, the lateral condyle of the tibia, and in the deep fascia of the lateral aspect of the leg. The semitendinosus, semimembranosus, and long head of the biceps femoris are all innervated from the tibial branch of
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Figure 2 Hamstring muscle group and its insertion on ischium.
the sciatic nerve. The peroneal branch of the sciatic nerve innervates the short head of the biceps. The fourth and fifth lumbar and the first, second, and third sacral nerves supply the muscles of this region. The action of the hamstring muscles is multitasked because of its bijoint design. At the knee, its primary job is flexion and secondarily it is tibial rotation. Because of this, stress is placed on those muscles dependent on the position of the hip and knee joints. Because of the high stress position with function, along with its ability to maintain posture and control of the pelvis during ambulation, almost any portion of the muscle has the potential for injury.
Mechanism of Injury Avulsion of multiple tendons can result in complex injuries in the pelvic region, especially in the pediatric age group with open growth plates. Hamstring strains or tears from the ischium are usually acute and dramatic. Adolescents are more likely to have a portion of the bone avulsed from the ischium, which can be detected radiographically, secondary to the apophysis being a weak link in the bony structure of this age group.12,13 Avulsions of the hamstring originating from the ischial tuberosity in adults, by contrast, are not as common and usually do not present
radiographically with bony involvement. Steinbruck14 reported that less than 4% of athletic injuries are complete tendon or muscle ruptures. Orava and Ala-Ketola15 reported only 1 of 34 consecutive avulsion fractures involved the ischial tuberosity. These injuries are described as extremely disabling and require a long period of rest and rehabilitation. Although conservative management is often recommended, cases in which bony fragments are displaced greater than 3 cm in the adolescent age group should be repaired. Hamstring muscle strains commonly result from a wide variety of sporting activities, particularly those requiring rapid acceleration and deceleration. Avulsion injuries can occur from a forced hip flexion with simultaneous knee extension.6,16-18 Eccentric loading of the muscle can produce forces sufficient to rupture the hamstrings.7,19 The force generated is concentrated at the myotendinous junction, in which the majority of these injuries occur.1,7,19 Whether dealing with the pediatric age group and bony avulsion or the adult population, the mechanism remains the same.
Diagnosis Hamstring tendon avulsions are rare injuries and are often difficult to distinguish from simple muscle strains (Table 1).
Table 1 Grading of Hamstring Muscle Strains Degree
Musculotendinous Unit
Pain
Swelling
Strength
Motion
First Second Third
No disruption Partial disruption Complete disruption
Mild Moderate Severe
ⴙ ⴙⴙ ⴙⴙⴙ
0 ⴚ ⴚⴚ
0 ⴚ ⴚⴚ
Hamstring avulsion injuries
83 Table 2 Hamstring Conservative Treatment Protocol
Figure 3 MRI (coronal, T1-weighted image) revealing complete hamstring avulsion with evident hematoma.
Typically, the history consists of a sudden onset of pain in the medial posterior pelvis, gluteal, or thigh region while the muscle is undergoing a voluntary or involuntary eccentric contraction with hip flexion and knee extension. Patients may also report feeling or hearing a “pop” at the time of injury and have difficulty with sitting. Normally, the patient will report weak knee flexion, but true weakness may be difficult to distinguish from painful guarding with an acute injury. Oftentimes, secondary muscle spasm may influence the patient’s subjective complaints. They may also have a feeling of
Figure 4 MRI (axial, T1-weighted image) revealing complete hamstring avulsion with evident hematoma.
Phase I Use of assistive devices Cryrotherapy Compression Elevation Electrical currents Phase II Cryrotherapy Stretch hamstrings, quadriceps, and hip flexors NSAIDs (nonsteroidal anti-inflammatory drugs) Electrical modalities for inflammation control Isometrics for hamstrings in a painfree ROM Core stabilization Isotonics, short arc eccentric Closed chain training Phase III Cryrotherapy Stretch hamstrings, quadriceps, and hip flexors NSAIDs Electrical modalities for inflammation control Isotonics, short arc eccentric Closed chain, high performance training Phase IV Cryrotherapy Stretch Running, gradually increasing in distance and time Sport-specific training Phase V Return to activity
instability, with a chief complaint of giving way while descending stairs. A palpable defect on the tendon, just distal to the ischial tuberosity, is common, especially with the complete avulsion of a portion of the ischial tuberosity. In addition, a loss of normal contour of the posterior thigh and ecchymosis may be noticeable when compared with the unaffected leg.17 The senior author has established a position of testing in which he terms a positive finding to be the “Garrett sign.” One should look for this “Garrett sign” by testing for decreased strength with resisted knee flexion and passive knee extension with the hip flexed at 90°. Timely diagnosis and treatment of ischial tuberosity avulsions are essential, secondary to the residual loss of power, excessive scarring in the avulsion area, and potential for muscular retraction.20 Patients develop chronic complaints of pain in the lower extremity, weakness, and cramping with walking and running.2,10,21 These patients also describe a loss of proprioception to the lower extremity and poor leg control, especially walking downhill on uneven surfaces, and explosive power.2,10 During extension of the knee in the swing phase, the hamstring muscles function eccentrically to decelerate the forward progression of the tibia.22 Timing of surgical intervention is a critical factor of tendon/muscle retraction. In multiple studies, cases of hamstring avulsions treated acutely with surgical intervention within 6 to 10 weeks of the injury yielded good results. Attempts to repair chronic avulsions
84
Figure 5 S-shaped incision centered in gluteal crease used for surgical procedure.
Colosimo et al process results in a positive outcome in most, its success in complete structural disruption is questionable. At the other end of the spectrum is the now well-described avulsion pathology of the hamstrings, which requires 3 to 4 months for complete functional return if nonsurgical intervention is elected. Initially, these injuries are treated with rest, icing, compression, analgesic medications, and protective weight bearing. A short period of immobilization is beneficial in limiting the extent of connective tissue proliferation, thus decreasing the occurrence and the amount of scar formation. In addition to being an analgesic, ice has been shown to limit inflammation and edema and slow metabolism. Compression wraps assist in controlling edema and limit the inflammatory response. Elevation is beneficial in controlling the vascular response. Crutches are recommended to allow the patient to ambulate without excessive pain or stresses on the injured site; they also facilitate normal gait patterns. Once acute symptoms abate, active exercise can be implemented. Initially, the resistance should be submaximal, using straight-leg raises and range of motion exercises. Isolated knee flexion exercises are slowly initiated using eccentric resistance at first and advancing to concentric loading.
after 12 weeks resulted in poor functional outcome, secondary to muscle/tendon retraction.1,6,16-18,21,23,24 In determining the extent of the injury, radiographic evaluation is helpful in all populations but especially in the pediatric age group. Ultrasonography and computer tomography (CT) scans have also proven valuable in evaluating these types of injuries. Positive findings on CT scans show the region of injury as an area of low density, associated with the presence of inflammation and edema or bleeding. CT scans, for diagnostic purposes of ischial tuberosity avulsions, are seemingly more useful in the subacute phase, approximately 1 to 3 weeks after the injury.25 Differential diagnosis for hamstring avulsions is critical, as the timing for surgical correction is best performed in the acute post injury phase. To facilitate this, magnetic resonance imaging (MRI) has evolved as the technique of choice due to enhanced visualization capability in evaluating the tendon during all phases of healing.1,23,25,26 MRI is also better at evaluating the location, extent, and severity of the injury, facilitating the correct diagnosis and rehabilitation for the patient (Figs 3 and 4). The amount of tendon retraction and the tendon edge morphology are important elements for preoperative assessment. Koulouris and Connell reported on the sensitivity and accuracy of MRI in verifying avulsion occurrence correctly in 16 of 16 patients compared with ultrasonography, which only identified 7 of 12.27
Treatment Standard intervention of partial muscle/tendon pathology incorporates a conservative program of stretching, use of nonsteroidal medication, modalities to control inflammation and pain, and strengthening (Table 2). Although this
Figure 6 S-shaped incision marked on patient showing ecchymosis from injury.
Hamstring avulsion injuries
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Figure 8 Fluoro-image after corrective procedure has been completed.
Figure 7 Hamstring repair technique using suture anchors.
Closed chain training is also incorporated into the program with advancement to full activity in 6 months. Surgical repair is indicated for either failed conservative treatment or for displacement of the bone greater than 2.5 cm.1,24,28-30 Advancement for advocating surgical repair has evolved because of recent studies reporting the persistent weakness in patients treated conservatively.1,20 Sallay and coworkers6 described acute repair of hamstring avulsions as a technically feasible procedure with good results. Moreover, they warned that delay in the repair increases the risk of poor results, secondary to chronic fibrosis, retraction, and muscle atrophy. Our experience with surgical indications, although similar, is also currently evolving. They include a positive “Garrett sign,” definitive MRI documentation, level of occupation or athletic participation, and failure of conservative treatment.
is taken not to place undue tension on the sciatic nerve, which is protected by retractors. Subsequently, the gluteus maximus is freed circumferentially and later retracted superiorly. Through this muscle, we can usually palpate the hamstring tendon avulsion, as the scar tissue is balled up and retracted from its original attachment site. The fascia over the hamstring is incised longitudinally, exposing the hematoma as well as the torn ends of the hamstring. The ischium is palpated, and the ischial tuberosity is then exposed. Using a bovie and a periosteal elevator, the periosteum is elevated from the ischium and the bone freshened. Two to 4 suture anchors with double strands are inserted into the ischium and can then be applied to the hamstring tendons; they are separated and tagged for later use.
Surgical Procedure The surgical procedure places the patient in a prone position with the knee flexed. The hamstring muscles are palpated, and a transverse S-type incision, made in the gluteal crease (Figs. 5 and 6), is carried down through the skin and subcutaneous tissues. Surgical dissection continues through the fascia of the inferior border of the gluteus maximus and exposes the gluteus maximus muscle. After it is identified, care
Figure 9 Radiograph after corrective procedure has been completed.
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86 Table 3 Hamstring Repair Rehabilitation Protocol Phase I (week 1 to 4) TTWB approximately 10–14 days 25% WB at 14 days and increasing 25% per week until off crutches at week 5 PROM as tolerated, starting in week 2, with hip and knee ROM Initiate gentle AROM around week 3 or 4 Discontinue brace post-op around day 21 to 28 Phase II (week 4 to 8) FWB is permitted if the patient demonstrates normal gait patterns Aquatic walking and ROM Closed chain emphasis with limited ROM Isotonics in limited range of motion, avoid terminal range of extension PROM knee extension and hip flexion Initiate core pelvic strength training Phase III (week 8 to 12) Progress isotonic strength training Advanced dynamic training Concentrate on core pelvic training Strength evaluation at 10 weeks-isometric mode only at 60° of knee flexion Phase IV (week 10 to 24) Begin dry land jogging/running Full isokinetic evaluation at 60°, 120°, and 180°/s, bilateral comparison Functional hop testing Sport specific activities Return to sporting activities
maintain this position until the initial visit to the physician’s office.
Postoperative Protocol Review of the current literature for postsurgical management of avulsions to the proximal hamstring has limited documentation providing a standard pathway. Klingele and coworkers22 recommended a period of limited range of motion and weight bearing but no specific exercise pathway or functional progression to full return to activity. Clanton and Coupe,1 in 1998, recommended a specific rehabilitation protocol for hamstring injuries in athletes, but this is a nonsurgical conservative approach with no mention of surgical pathway. The literature, therefore, lacks a pathway that minimizes risk of complication and provides insight to a safe exercise regime. The protocol we currently recommend is based on our experience in 9 consecutive cases over a 2-year period (Table 3). The pathway is designed to reestablish range of motion of both the hip and knee, regain proximal limb strength, facilitate a gradual relengthening of the hamstring, and progress function without repair disruption. The program is titrated over a 3- to 4-month period until resumption of function, based on achieving objective return to normal. In the immediate postsurgical period of 4 weeks, the patient is placed in a bijoint brace, which restricts hip and pelvic
Abbreviations: TTWB, toe-touch weight bearing; WB, weight bearing; ROM, range of motion; PROM, passive range of motion; AROM, active range of motion; FWB, full weight bearing.
Next, attention is turned to the hamstring avulsion. The mass of tendons is identified. They are brought together using a no. 5 Tycron stitch for temporary purposes. Once this is established, both the anterior and posterior ends of the hamstring musculature are freed from the soft tissue and scar tissue until they can be freely pulled to the level of the ischial tuberosity (Figs. 7-9). Once this is ensured, the suture anchors of no. 2 ethibond are then subsequently placed in Kessler-type (horizontal mattress type fashion) stitches through the proximal end of the hamstring muscles to secure the remainder of the hamstring tendon. It is then pulled forward to the ischium using the pulling stitch, and the sutures are subsequently tied in sequential fashion. This secures a very strong reattachment of the hamstring back to the ischial tuberosity, shown with flexion and extension of the knee. The sutures are tied with the knee flexed approximately to 30° and the hip in approximately 20° of extension. The repair does allow the knee to become completely straight; it is then brought back to 30° and held there for the remainder of the procedure. After this, the wounds are copiously irrigated and suctioned dry, and then the incision is closed. The patient postoperatively is placed in a brace with the hips in approximately 20° to 25° of extension and instructed to
Figure 10 Brace used postoperatively to prevent forward hip flexion (front view).
Hamstring avulsion injuries
87 single-leg balance, and proximal stabilization utilizing a coretraining program are keys to establishing normalized patterns of movement. Aerobic reconditioning must be undertaken in a low-load environment with advancement in time, which is as critical as stress application. Early initiation of retro training or backward ambulation in a pool, treadmill, or Stairmaster is beneficial to regain coordination and balance control.
Return to Activity/Play
Figure 11 Brace used postoperatively to prevent forward hip flexion (side view).
mobility. The brace is custom fabricated and maintains the hip in a neutral 0° position; maintaining the hip in this position limits stress at the reattachment site (Figs. 10 and 11). Also during this time period, the patient is restricted to toetouch non–weight-bearing gait pattern by using assistive devices such as crutches or a walker. The patient starts to come out of the brace after the first week for passive range of motion at the knee, while the hip remains in a nontensioned position. Starting at the fourth postoperative week, the brace is discontinued, and range of motion is reestablished, progressing through nonpainful ranges. Patients often are able to achieve 45° of hip flexion by this point. A full stretching program is only permitted after 6 weeks to gradually gain normal length to the hamstring muscle. Also, in the early phase, soft-tissue mobilization at both the insertion site and along the upper length of the hamstring muscle may be helpful in regaining motion and reducing scar development and pain. Toe touch weight bearing is initially permitted, and, after the second postoperative week, progression is made to partial weight bearing. The patient is then advanced an additional 25% of their body weight per week thereafter. Progression is made to 1 crutch at 5 weeks and the crutches are discontinued at the end of 5 weeks. For this progression to occur, advancement of a closed chain training program is recommended as well as reestablishing proprioception control of the limb. Inclusive exercises consisting of squats, leg press,
Return to recreational or competitive sports is recommended at a 4- to 5-month time period. Functional progression is based on sports-specific activity and emphasis on hamstring stretching before and after activity. Evaluation for return to sports involves both isokinetic dynamometer and functional testing. Isokinetic evaluation is done at 60°, 120°, and 180° per second velocity, with bilateral comparison recommended. Testing is done both at the knee and hip and bilateral comparisons are recommended to be within 15% of normal at slow and fast speeds. Furthermore, evaluation of the hamstring to quadriceps ratio should be 50% to 60% in the affected extremity at 60° per second, and the strength of the injured limb should be at least 85% of the opposite limb. Other criteria include equal restoration of flexibility, endurance, and single-limb position testing. Also validated in the literature is clinical evaluation by hop testing. The 2 tests we find most beneficial are the single-leg hop for distance and the single leg hop for time. Again, 85% symmetry is required for return to function. Functional evaluation, such as on-field testing, is critical and must be performed without symptoms before return to full activity.
Complications After open reduction and internal fixation of an ischial tuberosity fragment, the primary concern is fragment loosening. If fixation security is compromised, reattachment may be needed. In our experience, this has occurred 1 time, secondary to patient noncompliance in the acute phase of rehabilitation. On reattachment and proper progression through the pathway, the patient resumed full activity without complaints. As in all surgical procedures, other complications include infection, loss of motion, and chronic pain patterns, which can influence the rehabilitation period. We have not experienced this in our population, and other authors have not addressed this.
Conclusions Avulsion of the adult hamstring origin is an uncommon injury that occurs in less than 4% of all hamstring injuries.14 A comprehensive evaluation with complete physical examination, along with radiographic evaluation and the use of MRI, is essential for timely diagnosis. Complete ischial tubercle avulsion can compromise hamstring function. This has resulted in a change of treatment approach, necessitating surgical intervention. This aggressive approach is supported by
88 the literature for reattachment of the tendon to the pelvis in the acute phase of injury. Our experience, as with others, has shown better outcome results with surgical intervention compared with conservative treatment. Nonoperative treatment may result in weakness that is poorly tolerated in active patients. Current literature supports the ability to return to a recreational level of athletics after surgical repair. A consensus exists for acute primary repair to restore hamstring function. However, questions remain concerning the results of a professional level athlete requiring explosive ability of the hamstring muscle group for “normal” athletic function.
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Colosimo et al 13. Wootton JR, Cross MJ, Holt KW: Avulsion of the ischial apophysis. The case for open reduction and internal fixation. J Bone Joint Surg 72B: 625-627, 1990 14. Steinbruck K: Epidemiologic von sportverlezungen: 15-Jahres-analyse einer sportmedizinischen ambulanz. Sportsverletz Sportsch 1:2-12, 1987 15. Orava S, Ala-Ketola L: Avulsion fractures in athletes. Br J Sports Med 11:65-71, 1977 16. Orava S, Kujala U: Rupture of the ischial origin of the hamstring muscles. Am J Sports Med 23:702-705, 1995 17. Ishikawa K, Kai K, Mizuta H: Avulsion of the hamstring muscles from ischial tuberosity. Clin Orthop 232:153-155, 1988 18. Kujala U, Orava S, Jarvinen M: Hamstring injuries: Current trends in treatment and prevention. Sports Med 23:397-404, 1997 19. Bassewitz H, Mount J, Shapiro M: Speed trap: Hamstring injuries in athletes. Biomechanics 5:16-22, 1998 20. Brewer B: Athletic injuries: Musculotendinous unit. Clin Orthop 23: 30-38, 1962 21. Cross M, Vandersluis R, Wood D: Surgical repair of chronic complete hamstring tendon rupture in the adult patient. Am J Orthop 26:785-788, 1998 22. Klingele KE, Sallay PI: Surgical repair of complete proximal hamstring tendon rupture. Am J Sports Med 30:742-747, 2002 23. Kurosawa H, Nakasita K, Nakasita H, et al: Complete avulsion of the hamstring tendons from the ischial tuberosity: A report of two cases sustained in judo. Br J Sports Med 30:72-74, 1996 24. Servant C, Jones C: Displaced avulsion of the ischial apophysis: A hamstring injury requiring internal fixation. Br J Sports Med 32:255-257, 1998 25. Blasier RB, Morawa LG: Complete rupture of the hamstring origin from a water skiing injury. Am J Sports Med 18:435-437, 1990 26. Brandser E, El-Khouri G, Kathol M, et al: Hamstring injuries: Radiographic: Conventional tomographic, CT, and MR imaging characteristics. Musculoskeletal Radiol 197:257-262, 1995 27. Koulouris G, Connell D: Evaluation of the hamstring muscle complex following acute injury. Skeletal Radiol 32:582-589, 2003 28. Kujala U, Orava S: Ischial apophysis injuries in athletes. Sports Med 16:290-294, 1993 29. Milch H: Ischial apophysiolysis: A new syndrome. Clin Orthop 2:184193, 1953 30. Takayanagi H, Watanaba H, Shinozaki T, et al: Overgrowth of the ischial tuberosity complicating femoral bone and muscle atrophy: Implications for a delayed complication of malunited apophyseal avulsion fracture. Am J Orthop 27:308-312, 1998