CASE
A 43-year-old woman presented for examination 18 days after sustaining an injury while waterskiing slalom style. The mechanism of injury was acute flexion of the right hip with extension of the right knee as her left foot disengaged from the ski. She reported feeling a distinct “pop” in the back of her right knee and pain in her buttock at the area of the origin of the hamstring. She was unable to bear weight and noticed immediate erythema and swelling in her posterior thigh. In the weeks following the injury, she experienced a great deal of ecchymosis extending from her buttocks into her popliteal area (see Figure 1). Although functionally weak in the right hamstring, she had been slowly improving. She complained of dull, constant pain that worsened when she was sitting or driving and occasional sharp pain with sudden movements. Despite being a healthy, active woman, she had been unable to run since the injury.
On examination, she was able to walk with a slight limp, favoring the right leg. She demonstrated decreased 
range of motion and strength in the right hamstring. She did have a palpable defect in the muscle, which MRI identified as extending approximately 5.5 to 7 cm distal to the ischial origin (see Figure 2). She still had ecchymosis in her popliteal fossa that extended up into the right hamstring region. The patient provided photos she took during the week following the injury demonstrating the various stages of her ecchymosis. Based on the physical examination and the MRI findings, she was determined to have a complete avulsion of the proximal hamstring group at the ischial origin.
Surgical treatment The surgeon reviewed the case and discussed the patient's options with her. Based on her active lifestyle and her desire to return to a high level of activity, she elected for surgical repair. She underwent surgery 20 days after the initial injury.
With the patient in the prone position, a longitudinal incision of approximately 6 inches was made over the ischial tuberosity. The avulsed proximal hamstring tendon was identified and tagged; the insertion site on the ischial tuberosity was then identified, and two absorbable suture anchors were placed (see Figure 3 and Figure 4). Suture anchors were used to restore the proximal hamstring tendon to the ischial tuberosity. The sciatic nerve was carefully protected throughout the surgery. Before closing, knee range of motion was tested to evaluate the integrity of the repair, which was satisfactory. The wound was then approximated and closed.
Postoperative management The patient was kept toetouch weight bearing on crutches for a period of 2 weeks, after which she was given instruction on how to slowly wean off the crutches as tolerated over a period of 2 to 4 weeks. Eight weeks after surgery, she began formal physical therapy to improve flexibility, strength, balance, and proprioception, and to learn how to initiate sport-specific exercise without exacerbating symptoms. She has continued a home exercise program with good success.
DISCUSSION
Complete avulsion of the proximal hamstring muscle group from the ischial tuberosity is a rare injury, and reports in the literature of patients with this condition are sparse. Although strain-type injuries to the hamstring muscles do occur frequently in athletes, complete avulsion of the proximal hamstring complex from the ischial tuberosity is far less common. The usual mechanism of injury is a violent, eccentric hamstring contraction that occurs with the knee extended and the hip flexed.1,2 This injury tends to occur most often in persons who participate in the sports of waterskiing and bull riding.1-3
Several clinical characteristics are associated with complete proximal avulsion of the hamstring group, including a palpable defect and tenderness just distal to the ischial tuberosity, ecchymosis over the posterior aspect of the thigh, diffuse swelling over the posterior portion of the thigh, pain in the buttock, difficulty standing or walking, weakness in knee flexion, and associated functional disability.1,4-7 Patients will generally have a report of recent relevant trauma and acute onset of severe pain, and they will often describe a sharp “pop” associated with the injury.3,8 Because these symptoms are sometimes vague and because distinguishing complete avulsion from hamstring strain can be difficult, MRI is considered the diagnostic technique of choice.4,6,7,9
Early diagnosis and intervention are important components to a positive outcome in this type of injury. Initial management should include typical modalities of frequent ice application, compression wrap, crutches as needed, antiinflammatory medication, and prompt referral to an orthopedic surgeon. In general, early intervention with surgical repair is considered the treatment of choice for patients desiring a good outcome with functional return to activity. 1-7,9-11 Patients treated nonoperatively for the same injury have been shown to have a greater amount of functional limitation and poor leg control, and many are unable to run or return to sports that require agility.3,9
Overwhelmingly, authors who have reported on hamstring avulsion injury and subsequent repair have detailed the use of a 90-degree knee flexion splint for a period ranging from 2 to 8 weeks following surgery to protect the repair.1,3,5,6,8,9 However, this may be unnecessary in the management of such patients. The patient in this case was treated surgically and without the use of a postoperative flexion splint. At 5 months postoperatively, the patient reports satisfactory recovery thus far with no adverse outcomes. She is now able to walk briskly, jog lightly, and complete most of the same activities of daily living as prior to surgery without a noticeable difference.
Although complete avulsion of the proximal hamstring complex from the ischial tuberosity is a very rare injury, further investigation into this condition is warranted. Recommendations for future research would be to compare the outcomes of patients treated postoperatively using the flexion splint versus those who are kept nonweight bearing on crutches without the splint. Based on this patient, early surgical intervention, without the use of a postoperative knee flexion splint and with proper physical therapy, could be considered for treatment of acute avulsion of the proximal hamstring group from the ischial origin. JAAPA
Stephanie Stradley and Rose Backs are physician assistants with the Ohio State University Department of Orthopedics and Sports Medicine in Columbus, Ohio. John Grosel is an assistant professor at Marietta College and staff physician, Marietta Memorial Hospital, Marietta, Ohio. Christopher Kaeding is interim chair, Department of Orthopedics, and director, Division of Sports Medicine, Ohio State University. The authors have indicated no relationships to disclose relating to the content of this article.
Steve Wilson, PA-C, department editor
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