Case Report

A Unique Complication Following Arthroscopic Anterior Cruciate Ligament Reconstruction

Kevin M. Ouweleen, M.D., and J. Jeffrey McElroy, M.D.

Summary: The use of the middle third of a patellar tendon with bone blocks is a common and well-accepted technique for arthroscopic reconstruction of the anterior cruciate ligament.1-3 We report here a disconcerting fracture/avulsion pat- tern of the patella/patellar tendon mechanism that occurred in the early postopera- tive period. Key Words: Anterior cruciate ligament reconstruction-Complica- tion-Patella fracture.

A 21-year-old white man suffered a hyperextension injury to his left knee while playing recreational

football in October of 1993. He was evaluated in our orthopaedic clinic approximately 1 week later and was clinically diagnosed with anterior cruciate ligament (ACL) and mild medial collateral ligament (MCL) in- juries. He was treated in a hinged knee brace with progression of flexion and weight bearing. His MCL healed with no valgus laxity. Approximately 3 months after his injury, the patient noted continued “giving- way” with lifting and walking, and was unable to re- turn to sports. Physical examination at this time found greater than 6 mm anterior translation (Grade II Lach- man test), a positive anterior drawer and a positive pivot shift. Four months after the injury, the patient underwent arthroscopically assisted ACL reconstruc- tion with the central third of the patellar tendon. A bone/tendon/bone graft was obtained with the use of the Arthrex bone harvesting blocks (Arthrex Inc, Na- ples, FL) and an oscillating saw. Blocks approximately 9.5 x 7 x 30 mm were obtained proximally from

From The Mount Carmel Medical Center, Columbus, Ohio, U.S.A. Address correspondence and reprint requests to J. Jeffrey McEl-

roy, M.D., Mount Carmel Medical Center, 793 West State Street, Columbus, OH 43222, U.S.A.

0 1995 by the Arthroscopy Association of North America 0749~8063/95/1102-1173$3.00/O

the patella and distally from the tibia, and the graft was taken from the central third of a greater than 40 mm patellar tendon. The reconstruction was uneventful and the patient was placed in a hinged knee brace postoperatively.

Eleven days after reconstruction, when the patient was instructed to be partial weight-bearing with crutches and a brace, he was walking down steps with- out either. He reported hearing a “pop” followed by a giving way of his knee, which resulted in a fall of approximately 5 or 6 steps. He was evaluated in the emergency department where radiographs revealed a displaced patellar fracture (Fig 1) and loss of active knee extension. The patient was taken to the operating room 48 hours later for open reduction and internal fixation of the patella fracture. Intraoperatively, the patella fracture pattern as well as an unexpected avul- sion of the patellar tendon (Fig 1C) were noted. The ACL reconstruction was functionally and visibly in- tact. The fractured patellar fragment was comprised of the inferomedial quarter of the patella including the bone plug harvest trough. The lateral third of the patel- lar tendon, in continuity with the majority of the patella and quadriceps, was noted to be avulsed from the tibia1 tubercle.

The patella fracture was repaired with the use of 4.5-mm cannulated screws and a tension band wire, as described previously.4 After anatomic reduction of the

Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 11, No 2 (April), 1995: pp 225-228 225

226 K. M. OUWELEEN AND J. J. MCELROY

FIG 1. (A) Anterior-posterior and (B) lateral radiographs showing patella fracture. (C) Artist’s depiction of intraoperative findings. Note fracture through patellar bony trough and avulsion of remaining patellar ligament.

patella, the avulsed patellar tendon was anchored into Postoperatively, the patient’s range of motion was the bony trough (from the previously taken ACL graft) limited to 0” to 30” with partial weight bearing, crutch with the use of two Super Mitek anchors (Mitek Surgi- ambulation. In approximately 3 weeks, range of motion cal Products, Westwood, MA), and the medial and was increased to 0” to 45”. One month postoperatively, lateral third of the patellar tendon were sewn in a side- the patient felt a “pop” during active range of motion to-side fashion distally. Intraoperative anterior-poste- exercises and radiographs revealed that the cerclage rior, lateral, and merchant radiographic views were wire had broken (Fig 3), but remained asymptomatic. obtained (Fig 2) and an 1%gauge cerclage wire was Approximately 6 weeks after the repair, his range of placed from the patella to the tibia to protect the tendon motion was increased to 0” to 70” and the patient noted repair. painful “clicking” of the cerclage wire distally. The

A COMPLICATION OF ACL RECONSTRUCTION 221

FIG 2. Postoperative radiographs showing patellar reconstruction and cerclage wire. (A) Anterior-posterior view; (B) lateral view; (C) sunrise view.

patient was subsequently taken to the operating room for uncomplicated wire removal.

DISCUSSION

This case represents the second report of a com- bined patella fracture and patellar tendon avulsion after autologous patellar tendon ACL reconstruction. Although both injuries represent potential, although

infrequently reported, complications of this tech- nique, this case of a combined injury was unantici- pated. Intraoperative review of the harvest site by a number of orthopaedic surgeons at our facility was unable to detect any evidence of errant saw cuts or overzealous or off-center graft harvesting. We are also unable to determine the sequence of failure and theorize that the patella fracture led to an overloading of the remaining lateral third of the patellar tendon

228 K. A4. OUWELEEN AND J. J. MCELROY

FIG 3. Anterior-posterior view radiograph showing failure of cer- clage wire.

causing avulsion of the tendon from the tibia. Previ- ous investigators have described reattachment of the patellar tendon with a staple and Bunnell suture.5 We

elected to repair the tendon into the cancellous bone of the tibia1 trough using two Super Mytek anchors and side-to-side repair of the distal half of the tendon. This injury appears to have resulted from patient non- compliance, and occurred in a manner similar (stair ambulation) to that of a previous report. A patella fracture status after ACL reconstruction should alert the orthopaedic surgeon to the possibility of a con- comitant patellar tendon avulsion especially when there is significant fracture displacement and disrup- tion of the extensor mechanism of the knee. Bone grafting of the patella may prevent complications of this nature over the long term; however, the acute nature of this fracture could not have been circum- vented by bone grafting. With a trend toward imme- diate mobilization and aggressive rehabilitation, complications such as this may become more fre- quent.

Acknowledgment: Special thanks to Jennifer Hill for manuscript preparation.

REFERENCES

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Jones KG. Reconstruction of the anterior cruciate ligament: A technique using the central one third of the patellar ligament. J Bone Joint Surg Am 1963;45:925-932. Jones KG. Reconstruction of the anterior crnciate ligament using the central one third of the patellar ligament: A follow-up report. J Bone Joint Sura Am 1970:52:1302-1308. Jones KG. Results of use fo; the central one-third of the patellar ligament to compensate for ACL deficiency. Clin Orhop 1980; 147:39-44. Carpenter JE, Kasman R, Matthews LS. Fractures of the patella. J Bone Joint Surg Am 1993;75:1550-1561. Bonatus Timothy J, Alexander AH. Patellar fracture and avulsion of the patellar ligament complicating arthroscopic anterior cruci- ate ligament reconstruction. Orthop Rev 1991;20:770-774.