Orthopedics

Materials and Methods

After institutional review board approval, the authors conducted a retrospective review of 8 consecutive adolescent basketball players who underwent open reduction and internal fixation for acute tibial tubercle avulsion fractures by the senior author (J.R.) between August 2003 and September 2007. All patients were immobilized in a cylinder cast or brace for 4 weeks postoperatively. Medical records were reviewed to identify age, sex, involved side, fracture type by the Ogden classification (modification of Watson-Jones), concomitant injuries, treatment, complications, and outcomes after return to play.

Open reduction and internal fixation was performed using 1 or 2 screws, depending on fracture type. Dissection was performed through an anterior approach to the tibial tubercle using a midline vertical incision. Cancellous bone screws were then used to secure the fracture fragments. Screws were placed horizontally through the tubercle into the metaphysis under fluoroscopic guidance, taking care to avoid overpenetration of the posterior tibial cortex. A single screw was used to secure type 2 fractures. Two screws were used for type 3 fractures (Figures 1–3).

Figure 1: Lateral radiograph of the right knee with type IIIA tibial tubercle avulsion fracture.

Figure 2: Postoperative lateral radiograph of the right knee after 2-screw insertion for the treatment of type IIIA tibial tubercle avulsion fracture.

Figure 3: Postoperative anteroposterior radiograph of the right knee after treatment of a type IIIA tibial tubercle avulsion fracture.

Long-term outcome was assessed with the Short Form 36 Health Survey (SF-36) and Lysholm knee score. Patients were mailed the SF-36 and replied over a 4-month period. Each patient was then contacted via telephone, and Lysholm knee scores were determined by their responses to all questions on the scale.

The SF-36 is a validated instrument useful for estimating disease burden and comparing disease-specific benchmarks with general population norms, as illustrated in articles describing more than 200 diseases and conditions, including surgical procedures in relationship to ambulation.¹⁰ The SF-36 is divided into 8 scales, which form 2 distinct higher-ordered clusters: physical and mental. Three scales (physical functioning, role-physical, and bodily pain) correlate most highly with the Physical Component Summary measure and were especially considered in the data tabulation.¹¹ The reliability of the 8 scales and 2 summary measures has been estimated using both internal consistency and test–retest methods.¹⁰ Published reliability statistics have exceeded the minimum standard of 0.70 recommended for measures used in group comparisons in more than 25 studies and usually exceed 0.90.¹¹

The Lysholm knee scale is a validated, condition-specific outcome measure useful for calculating psychometric performance in various disorders of the knee.^12,13 Significant correlations have been made between the overall Lysholm knee scale and physical functioning, role-physical, and bodily pain domains of the SF-36.¹³

Results

Eight patients with 8 tibial tuberosity fractures were observed for this study. Mean age at time of injury was 13.7 years (range, 12 years 9 months to 15 years 6 months). Initial diagnosis was made in the emergency room in 6 of 8 patients, with 2 diagnoses being made in the outpatient clinic setting. All 8 patients were boys, and 5 had right-side injuries and 3 had left-side injuries. The mechanism of injury was the same for all patients in this study: landing from jumping while playing organized basketball. Table 1 details patient data.

Table 1: Patient Data

Initial findings on physical examination included swelling of the anterior proximal tibia, a palpable deformity, mild ecchymosis, and diffuse tenderness. Competency of the extensor mechanism of the knee was tested with a straight leg raise. The diagnosis of an acute tibial tubercle avulsion fracture was confirmed with a lateral radiograph. None of the 8 patients had a previous documented history of Osgood-Schlatter disease or preexisting anterior knee pain. No concomitant injuries were associated with any patient, including patellar or quadriceps avulsions, collateral or cruciate ligament tears, or meniscal damage.

The Ogden modification of the Watson-Jones classification was used to describe each patient’s injury severity (Table 2; Figure 4).⁴ A type 4 fracture has been proposed by Ryu and Debenham¹⁴ in which the tuberosity fracture extends posteriorly along the entire proximal tibial physis. Type 5 fractures have been described by McKoy and Stanitski¹⁵ in which a type 3B fracture is combined with a type 4 fracture to create a “Y” configuration. The fracture fragments were displaced in all patients in this study. Four patients had type 2A fractures, which were treated with open reduction and a single screw. Four patients had type 3A fractures, which were treated with a 2-screw technique.

Table 2: Ogden Classification

Figure 4: Schematic of the Ogden Classification System.

All patients were examined in the acute care or outpatient setting over the follow-up period. Minimum postoperative follow-up was 24 months. No complications, such as infection, fracture malunion or non-union, hardware failure, compartment syndrome (pre- or postoperatively), or limb deformity, were observed. Range of motion exercises were started an average of 4 weeks postoperatively. Return to activity was reported an average of 4 months postoperatively, and return to basketball at a pre-injury level was reported by all patients an average of 9 months postoperatively. The rehabilitation protocol was followed strictly by each patient. The protocol allowed each patient to bear weight with no limitation at 4 months, which also included full, unrestricted jumping exercises. Full knee range of motion and quadriceps strength compared with the uninvolved side were restored in all patients at last follow-up. No patient had evidence of growth disturbance of the proximal tibia or recurvatum at final follow-up.

Three patients reported mild joint line tenderness on cast removal during the early follow-up period. This may be attributed to potential meniscal injury stemming from type 3 fractures extending beyond the joint surface. A limited anterior surgical approach was performed in all cases, with fluoroscopy being used to assess reduction of the fracture fragments. The joint surface was not explored during the procedure.

Between November 2010 and February 2011, SF-36 surveys were obtained. Each patient who was contacted replied to the survey; in some instances, several patients had been discharged from the practice due to previously documented full recovery at last follow-up and length of time from initial onset of injury. All patients indicated excellent physical health (Table 3). Their perceptions were further validated by subsequently reviewing each patient’s Lysholm knee score (Table 4).

Table 3: Short Form 36 Health Survey Patient Response Data

Table 4: Lysholm Knee Scale

Discussion

Tibial tubercle avulsion fractures are uncommon injuries that usually occur in adolescent male athletes as isolated injuries. They result from pushing off or landing while jumping as the quadriceps eccentrically contract, causing a direct force to be placed at the area of the patellar tendon insertion.^1,2,5,6 When the force is greater than the strength of the tibial tubercle physis, a fracture is created. The fracture propagates through the proximal tibial epiphysis and may extend into the anterior portion of the knee joint. Because the proximal tibia physis closes from posterior to anterior, the fracture pattern is dependent on the amount of physeal closure present at the time of injury.^1,5,6 Predisposing factors include patella baja, tight hamstrings, preexisting Osgood-Schlatter disease, and disorders involving physeal abnormalities.^1–3

Management of tibial tubercle fractures is primarily based on the injury severity and fracture pattern. The Ogden classification is most commonly used to classify and treat these fractures. Type 1A fractures are managed nonoperatively, with immobilization in a long-leg or cylinder cast. Operative fixation has been advocated for types 1B through 5. Many fixation options are available to address these injuries. Open reduction of displaced fragments with fixation by cancellous screws is effective. Percutaneous cannulated screw fixation can be attempted for fracture types that extend to the joint and have minimal displacement.^7–9

Fixation with cancellous bone screws achieved bony union in all patients in this study. The authors recommend open reduction and a single screw for type 2 fractures. An additional screw is necessary for type 3 fractures. The senior author’s postoperative course of strict nonweight bearing and a cylinder cast or brace was well tolerated by all patients in this study. Casting is favored over bracing due to potential non-compliance in this adolescent patient population. Guided physical therapy beginning with range of motion exercises at 4 weeks and progression back to full weight bearing over 12 weeks proved successful in all patients and led to a return to sports participation at an average of 9 months.

Treatment modalities continue to be developed for this injury type. Arthroscopic-assisted open fixation has been described.⁷ Fixation with various combinations of wires, suture repairs, and tension band techniques have been used with good results.⁸ The outcomes were excellent in the current study, in which simple open reduction and internal fixation techniques with cancellous screws were used. Three patients in this study had mild joint line tenderness during the immediate postoperative period at the time of cast removal. The pain resolved in all patients but could represent a type 3 fracture involving the articular surface and overlying meniscus. The meniscus may also have been trapped between 2 fragments during reduction because the procedure was performed under fluoroscopic guidance rather than direct visualization of the joint. An arthroscopic-assisted procedure may aid reduction in the future, as well as assess any meniscal pathology that may stem from this fracture type. This technique would be most useful in a type 3 fracture. An additional exposure through a small medial parapatellar arthrotomy could also be used if suspicion of meniscal injury was high or articular reduction needed to be confirmed.

All patients in this study were able to return to participation in basketball. The SF-36 results point to no hindrance with activities of daily living. All categories that would confirm physical recuperation were answered negatively by all patients, including limitation of activities, physical health problems, and pain. These results were further confirmed by the excellent Lysholm scores for each patient.

Complications are relatively unusual but can have potentially devastating effects. Recurrent deformity, especially recurvatum of the tibia, has been described.^1–7,9 Currently, no specific age cutoffs exist for the development of recurvatum deformity, but considering that the physeal closure in adolescent boys occurs between 15 and 19 years, if an injury were to occur earlier in life, a higher potential would exist for recurvatum deformity. Compartment syndrome in the anterior compartment of the lower leg is also possible.^1–7,9,14 Some authors report using prophylactic fasciotomy to avoid this potential complication.⁷ Percutaneous methods have also been cited as posing an increased risk for compartment syndrome.⁸ Refracture can occur if strict postoperative rehabilitation protocols are not followed by the patient.^1–4,7 Arthrofibrosis of the knee is a potential concern, especially if arthroscopic-assisted techniques are used.⁷ No instances of compartment syndrome were observed in the current study. Other complications, such as malunion, nonunion, refracture, hardware failure, genu recurvatum, deep venous thrombosis, neuroma formation, limb-length discrepancy, and tibial tubercle pain, were not encountered in this study.

This study used the SF-36, which is a validated general health outcome measurement, and the Lysholm knee scale, which is a joint-specific outcome measurement scale. The SF-36 is validated in English and Spanish, which was a factor in the patient population served by the tertiary medical center in this study. The Lysholm knee scale was initially developed with ligamentous injury in mind but has been validated for other knee procedures and found to be easy to use.¹³ The International Knee Documentation Committee Subjective Knee Form may be a better choice for future follow-up of this injury type with its ability to assess any condition involving the knee. The form’s main strength is the ability to assess groups with different diagnoses; thus, the current authors decided not to use it because the study had only 1 injury. The Marx scale assesses running, cutting, decelerating, and pivoting, all of which are required for basketball. However, the Marx activity scale does not assess jumping or landing, which were the main injury physiologies found in this study, so it was not chosen for outcome measures. Future assessment of return to play following this injury could include the Marx activity scale.

The major limitation of the study was its retrospective nature. Small sample size was also a limiting factor. Several patients had to be excluded from the study because their treatment occurred before conversion to electronic medical record storage and prior to Picture Archiving and Communication System use at the authors’ institution. Referral bias may also be an issue because all treatment was performed at a tertiary referral center.

Conclusion

Return to play results at the preinjury level were favorable after treatment of acute tibial avulsion fractures in adolescent basketball players. Long-term outcomes were excellent in all patients regardless of fracture type. Open reduction and internal fixation using 1 or 2 cancellous bone screws achieved union in all cases. Arthroscopic-assisted procedures may prove beneficial in addressing meniscal pathology and confirming articular surface reduction in type 3 fractures.