Correction of Genu Recurvatum Secondary to Osgood-Schlatter Disease: A Case Report

Abstract

Complications secondary to Osgood-Schlatter disease are rare, and there have been few reports on their treatment. Partial growth arrest of the proximal tibial physis as a result of Osgood-Schlatter disease has been infrequently described. Genu recurvatum from partial physeal arrest can cause cosmetic deformity, instability, pain, and weakness. We report a case of genu recurvatum secondary to Osgood-Schlatter disease treated successfully with proximal tibial osteotomy and distraction with a Taylor spatial frame.

CASE REPORT

A 15- year-old boy presented with right knee pain and deformity. He had a several year history of anterior knee pain directly over an enlarged tibial tubercle, related to playing football. He had no history of trauma or infection. Over the preceding year, his symptoms had been worsening and his knee began to feel increasingly unstable. He also noticed right knee hyperextension. He reported a significant growth spurt during the previous year. He had an older brother with similar symptoms, who had been diagnosed with Osgood-Schlatter disease.

Physical examination revealed no deformity in the coronal plane; however, in the sagittal plane he had obvious recurvatum of his right knee with approximately 20 degrees of hyperextension. His knee range of motion had been shifted 20 degrees into extension. He lacked 20 degrees of flexion compared to the normal side. By block exam, his affected leg was 1.5 centimeters short. There was no deficit in total range of motion. Ligamentous exam of both knees was normal.

Scanogram of the lower extremities revealed a 1.6-centimeter leg-length discrepancy with the left (unaffected) leg longer. Radiographs revealed normal coronal alignment; however, the lateral view showed recurvatum of 17 degrees with obvious anterior slope of his tibia (Figure 1). His posterior tibial angle, as described by Paley and Tetsworth,¹⁵ measured 107 degrees (normal 77-84).

Figure 1.

(a) Lateral radiograph and (b) long-leg lateral radiograph showing the anterior tibial slope causing a severe recurvatum deformity

Due to persistent symptoms despite bracing, surgery was elected. The deformity was corrected gradually with the Taylor spatial frame. The frame was applied first so as to mimic the deformity (Figure 2). The osteotomy was performed percutaneously with a Gigli saw just below the tibial tuberosity. Over the next month, his deformity was corrected with daily changes in strut length pre-calculated by the computer program. After one month of correction, his frame was maintained during the consolidation phase until osteotomy healing was complete (Figure 3). During this time the patient was able to perform range of motion and strengthening exercises (Figure 4). During the consolidation phase he acquired a superficial pin tract infection that resolved after removal of the pin and a short course of antibiotics. Follow-up radiographs revealed correction of the genu recurvatum, equal leg lengths, and a healing osteotomy site. At final follow-up, he had returned to playing football and had symmetric full range of motion of the knee.

Figure 2.

The fixator is applied so as to mimic the deformity. The proximal and distal rings are orthogonal to their respective segments. Note the percutaneous Gigli saw osteotomy just below the tubercle.

Figure 3.

After the correction, the frame is neutral.

Figure 4.

Use of a 2/3-diameter ring proximally allows full knee flexion.

DISCUSSION

Osgood-Schlatter disease is characterized by pain, swelling, and enlargement of the proximal tibial tubercle at the site of attachment of the patellar tendon. The disease was first described in 1903 by Osgood and a few months later by Schlatter. It occurs in preadolescent children, usually in boys between 11 to 15 years of age and girls 8 to 13 years of age. It is more common in boys.

The etiology of Osgood-Schlatter disease is not known. Avascular necrosis (AVN), systemic disease, endocrinopathy, structural changes in the patellar tendon, and traumatic avulsion of the cartilage have all been proposed as etiologic theories. In 1975, Ogden and Southwick, through gross and histologic studies, found that Osgood-Schlatter disease appears to be an inability of the developing secondary ossification center to withstand tensile forces, resulting in avulsion of segments of the ossification center and eventual formation of extra bone between the fragments.¹² AVN appears an unlikely etiology in light of several studies showing that there is excellent blood supply to the anterior, lateral, and medial surfaces of the tuberosity. In addition, the disease does not display the remodeling seen with avascular necrosis. ⁴ It is now believed that Osgood-Schlatter disease is caused by repetitive microtrauma to the proximal tibial tubercle from the contracting quadriceps mechanism during a growth period when the tibial tubercle is susceptible to strain. The symptoms of Osgood-Schlatter disease usually resolve without treatment or with simple conservative treatment such as restriction of activities or cast immobilization for three to six weeks. In 1990, a review of the natural history of untreated Osgood-Schlatter disease found that 76 percent of patients had no limitation of activity.⁷ Surgery, although rarely indicated, may be considered if symptoms are persistent or severely disabling. Surgical treatment options include tibial sequestrectomy, insertion of bone pegs into the tibial tuberosity, or excision of an ununited tibial tuberosity. ¹¹

Complications of Osgood-Schlatter disease are rare. Ogden and Roberts reported on complications of Osgood- Schlatter disease with or without treatment. These included subluxation of the patella, patella alta, nonunion of the bony fragment to the tibia, and premature fusion of the anterior part of the epiphysis with resulting genu recurvatum.¹¹ In 1981, patellar tendon avulsion was reported as a complication of Osgood-Schlatter disease.² Pseudarthrosis between the patellar tendon ossicle and the tibial tuberosity was diagnosed with histologic examination in a patient with symptoms of Osgood-Schlatter disease.¹⁷ An association between avulsion fractures of the tibial tuberosity in adolescents and Osgood-Schlatter disease has also been reported. Nimityongskul, Montague, and Anderson in 1988 presented a series of eight patients with tibial tuberosity avulsion fractures; six of the patients had prodromal symptoms prior to injury.¹⁰ Ogden suggested a relationship between the development of Osgood-Schlatter disease and subsequent acute avulsion of the tibial tuberosity. He presented 14 patients with physeal fractures of the tibial tuberosity; nine of them had pre-existing Osgood-Schlatter disease.¹³

Genu recurvatum as a complication of Osgood Schlatter disease is rare, and few cases have been reported. An extensive Medline search revealed five reported cases. A sixth case was reported by Pappas in 1984; however, this case was a recurvatum deformity in a patient with Osgood-Schlatter disease who had also undergone tibial wire traction and spica casting for treatment of two femoral fractures, and thus had several potential causes of recurvatum.¹⁶ Risk factors for physeal arrest of the proximal tibia include unrecognized trauma, tibial traction, Osgood-Schlatter disease, and prolonged immobilization. It was noted that more than half of Pappas' patients with recurvatum deformity had previous injury and half had been treated with tibial traction.¹⁶ In 1952, Stirling first described premature fusion of the anterior tibial physis as a complication of Osgood-Schlatter disease. ¹⁸ In 1965, Jeffreys reported a case of Osgood-Schlatter disease resulting in enough recurvatum deformity to require correctional osteotomy.⁶ Zimbler reported a case of recurvatum deformity from physeal arrest as a possible complication of Osgood-Schlatter disease. In this case, they successfully corrected a 20-degree recurvatum deformity and a 10-degree valgus deformity with a proximal tibial osteotomy and an autogenous iliac crest bone graft.²¹ In 1991, two cases of tibial recurvatum were reported by Lynch and Walsh, who recommended the need for regular screening for this rare complication of Osgood-Schlatter disease.⁹

Injuries to the proximal tibial physis are very rare, with a reported incidence of between 0.5 and 3.1 percent of all epiphyseal injuries.¹⁶ Angular deformities related to such injuries are also rare. The maturing physis is most susceptible to injury, and adolescent patients have been reported to have the highest incidence of physeal injuries. The tibial tubercle, with its subcutaneous position, is subject to direct trauma that may arrest the growth of the anterior part of the tibial physis resulting in genu recurvatum.^5,19 The most commonly reported complication is angular deformity and leg-length discrepancy.

Treatment options include acute and gradual correction techniques.^1,3,8,16 Although opening wedge osteotomies with bone graft can correct angular deformity and some shortening, the technique is exacting and risky. Circular external fixation allows for an infinitely adjustable correction that can be obtained gradually and fine-tuned as the correction progresses. The over-all time to healing is similar to opening wedge techniques, and full weight bearing is allowed from the outset. In addition, the frame allows the knee to be free for range of motion. We believe this is an excellent treatment option for many deformities of the proximal end of the tibia that would benefit from opening wedge techniques. It is well tolerated by patients, extremely accurate, and safe.