October 18, 2023

6 min read


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A 23-year-old female, former collegiate cheerleader with a history of right patellar instability presented to the ED with acute onset of sharp, severe pain in her right knee after feeling a pop when attempting to do a jump-squat.

Notably, she did report an insidious aching discomfort in the proximal tibia for several weeks prior to the injury. Her previous patellar instability had been treated surgically 3 years prior, including medial patellofemoral ligament reconstruction, matrix-induced autologous chondrocyte implantation of the patella and tibial tubercle osteotomy (TTO) with anteromedialization. She had an uneventful post-surgical course and recovered fully, returning to all activities, including multiple impact sports (cheerleading, dancing and martial arts).



Key Points Graphic



A focused physical exam demonstrated well-healed surgical scars with no signs of deformity of the right lower extremity. Tenderness to palpation was noted over the anterior proximal tibia, which was most pronounced over the screw sites. There was no evidence of patellar pain or apprehension on exam, as well as a negative J-sign. Her extensor mechanism was intact, and the distal neurovascular examination was normal.

Andrew Bi
Andrew Bi
Pooja Prabhakar
Pooja Prabhakar

Initial plain radiographs demonstrated a nondisplaced complete transverse proximal tibia fracture, originating just proximal to the inferior TTO screw (Figures 1a and 1b), suggestive of a completed stress fracture given her antecedent pain.

tib-fib radiographs 3 months postoperative are shown demonstrating nondisplaced proximal tibial fracture
Figure 1. Anteroposterior (a) and lateral (b) tib-fib radiographs 3 months postoperative are shown demonstrating nondisplaced proximal tibial fracture with intact hardware.

Source: Andrew Brash, MD

The patient was initially treated nonoperatively with a long leg splint for 3 weeks, long leg cast for 3 weeks and a hinged knee brace for another 3 months. However, at 5-month follow-up, she continued to complain of aching discomfort in the proximal leg and a CT scan revealed nonunion of 70% of the tibial cortex at the level of the inferior screw (Figure 2).

CT of tibia 5 months after injury
Figure 2. Sagittal and coronal cuts of CT of tibia 5 months after injury are shown demonstrating nondisplaced proximal tibial fracture nonunion hardware.

What are the next best steps in management of this patient?

See answer below.

Intramedullary nailing and bone marrow aspirate concentrate augmentation

Due to the failure of nonoperative management and resultant proximal tibia nonunion near her prior TTO hardware, it was recommended that the patient undergo surgery, consisting of removal of TTO hardware, tibial intramedullary nailing (IMN) and bone grafting.

Surgical technique

Surgery was performed under general anesthesia. First, bone marrow aspirate was harvested from the ipsilateral right iliac crest and concentrated in standard fashion before turning attention to the tibia. Next, the previous two cannulated, headless compression TTO screws were removed under fluoroscopic guidance. The tibial fracture extent into the anterior cortex was identified at the level of the inferior screw; overall, neither the TTO nor the nonunion of prior stress fracture were mobile. The osteotomy was noted to be well healed, as was the posterior extent of the proximal tibial nonunion. A 9-mm x 270-mm tibial IMN was placed using a standard infrapatellar technique, reaming to 10.5 mm to both increase nail size and to deposit autogenous bone graft at the nonunion site. Proximally, one 5-mm proximal interlocking screw was placed into the dynamic hole to allow for auto-dynamization of the fracture (Figure 3) and one interlocking screw was placed distally as well. Prior to closure, the autogenous bone marrow aspirate concentrate was combined with demineralized bone matrix and placed into the previous inferior screw hole, along the fracture site and onto the anterior cortex of the tibia. Incisions were closed in a standard fashion.

Intraoperative fluoroscopy, anteroposterior view of proximal tibia with intramedullary nailing
Figure 3. Intraoperative fluoroscopy, anteroposterior view of proximal tibia with intramedullary nailing and locking screw is shown.

Postoperative rehabilitation

The patient was permitted to weight-bear as tolerated immediately postoperatively in a controlled ankle motion walker boot and with crutches; she was able to wean from both within 2 weeks after surgery. By 3 months postoperatively, the patient’s pain had completely resolved, she was ambulating without any assistive devices and was permitted to resume light-impact activities. By 7 months after surgery, the patient had no pain; demonstrated full motion, strength and function; and radiographs demonstrated evidence of bridging callus at the tibial cortex, although lucency from screw sites was still visible (Figures 4a and 4b). At this time, the patient was allowed to resume full athletic activities.

tib-fib radiographs 7 months postoperative are shown demonstrating bony bridging
Figure 4. Anteroposterior (a) and lateral (b) tib-fib radiographs 7 months postoperative are shown demonstrating bony bridging along the anterior tibial cortex.

Discussion

The risk of proximal tibial fracture following TTO with anteromedialization is reported to be as high as 5.9%. Prior reports have detailed successful treatment with nonoperative methods, and this approach may be applicable to fractures emanating from the distal osteotomy site in the early postoperative period. However, as demonstrated by this case, nonoperative methods are not universally successful and surgical management may be indicated, especially for late-presenting fractures.

Sander Koëter, MD, PhD, and colleagues describe two patients in their cohort of 60 that sustained a proximal tibial fracture following a medializing TTO. One was treated nonoperatively, while the other was managed successfully with open reduction and internal fixation (ORIF). These fractures occurred 6 and 7 weeks after surgery and were attributed to poor osteotomy technique — making too thin of a cut or using a steep cut, which can create a stress riser in the tibial cortex. Johan Bellemans, MD, PhD, and colleagues described four cases of proximal tibial fractures following TTO with anteromedialization, including three patients managed nonoperatively and one patient treated with an Ilizarov external fixator; all patients were kept non-weight-bearing for 8 weeks and healed without complications. Each of these fractures occurred within 2 months of surgery and all were located at the level of the distal osteotomy site. They were attributed to intense activities occurring too early in the postoperative period before adequate healing. Other risk factors for fracture reported in the literature include an overly aggressive osteotomy cut that violates the posterior cortex of the proximal tibia. Scott J. Luhmann, MD, and colleagues reviewed various TTO techniques and concluded that the use of an incomplete “greenstick” style distal osteotomy along with minimal distal periosteal stripping improved bony consolidation and had the lowest risk of postoperative tibial fracture of the osteotomy site.

In this case, the decision was made to treat the patient with IMN as opposed to ORIF using a pre-contoured proximal lateral tibial plate. The benefit of using an IM nail is its ability to share load, allowing earlier weight-bearing when compared to plates, as well as preventing any future peri-implant fractures. For extra-articular proximal tibia fractures amenable to both IMN and ORIF, studies have demonstrated IMN results in decreased time to weight-bearing, contributing to earlier mobility. Further, the incorporation of bone marrow aspiration concentrate (BMAC) for the treatment of tibial nonunions has displayed excellent results. BMAC works by effectively recovering nucleated cells from the bone marrow, providing biological stimuli for osteogenesis at the fracture site.

Our case is unique in that the proximal tibia fracture occurred at or near the level of the inferior TTO screw and was delayed in presentation, occurring more than 1 year after TTO and with a healed osteotomy site. One possible explanation for this is the creation of a stress riser at the location of the inferior screw. The abrupt change from cortical bone to metal serves as an area of stress concentration. In addition, this may shield and potentially weaken the adjacent tibial cortex, increasing the risk of fracture in the area of relatively high stress concentration. This risk can be perpetuated if a properly sized shingle of bone is not created, such as a tuberosity fragment that is less than 5 cm in length and 5 mm in thickness. While not common, the surgeon should be aware of this potential complication in the postoperative period, even after osteotomy union, and perhaps consider the role of operative treatment with these specific fractures sooner rather than later after presentation. Further study is needed to understand and help prevent this complication, such as the role of countersinking or use of headless screws, perioperative bone density tests to determine those at risk, high impact activity limitations postoperatively and even the role of prophylactic screw removal and screw site bone grafting.

Key points:

  • Proximal tibia fracture after TTO is not uncommon, with a reported incidence of approximately 6%.
  • Postoperative fractures related to delayed healing of the osteotomy site may be successfully treated nonoperatively; however, later presenting fractures at the level of the inferior screw may fail conservative treatment.
  • Proximal tibia fractures emanating from the inferior screw may be effectively treated with hardware removal, IMN and bone grafting of the fracture site.

Sources/Disclosures

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Source:
Bellemans J, et al. Am J Sports Med. 1998;doi:10.1177/03635465980260022401.


Disclosures:
Bi, Brash, Golant and Romeo report no relevant financial disclosures.

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