KNEE

ORTHOPEDICS May 2011;34(5):397.

Transphyseal Anterior Cruciate Ligament Reconstruction in a Skeletally Immature Knee Using Anterior Tibialis Allograft

by Yool Cho, MD; Soo-Jin Jang, MD; Jung-Hwan Son, MD, PhD

Abstract

Anterior cruciate ligament (ACL) injury in the skeletally immature individual is being recognized with increasing frequency. Nonoperative treatment of ACL injuries in skeletally immature patients have not been favorable. Surgical treatment options for complete ACL tears include primary ligament repair, extraarticular tenodesis, transphyseal reconstruction, partial transphyseal reconstruction, and physeal-sparing reconstruction. The advantage of transphyseal reconstruction is placement of the graft tissue in an isometric position, which provides better results, according to the literature. The potential disadvantage is angular or limb-length discrepancy caused by physeal violation. Controversy exists in allograft selection about whether bone or soft tissue passes into physes. The use of standard tunnels provides reliable results, but carries the risk of iatrogenic growth disturbance from physeal injury.

This article presents 4 cases of transphyseal ACL reconstruction using anterior tibialis allograft in skeletally immature patients that had satisfactory functional outcomes with no growth disturbances. This is the first report of transphyseal ACL reconstruction using anterior tibialis allograft in skeletally immature patients in the English-speaking literature. All patients underwent transphyseal ACL reconstruction using anterior tibialis tendon allograft. None of the patients had angular deformities. No early physeal arrest was measured between the preoperative and postoperative radiographs. At last follow-up, the results of the Lachman test were normal for 3 patients and nearly normal for 1 patient. All patients demonstrated full range of knee motion (comparing the reconstructed knee to the contralateral knee). The results of the pivot-shift test were normal for 3 patients and nearly normal for 1 patient. No patients reported giving way.

Anterior cruciate ligament (ACL) injury in the skeletally immature individual is recognized with increasing frequency.^1-3 Nonoperative treatment of ACL injuries in skeletally immature patients has not been favorable.^1,4,5 Surgical techniques to address ACL injuries in these patients include primary ligament repair, extraarticular tenodesis, transphyseal reconstruction, partial transphyseal reconstruction and physeal-sparing reconstruction.^3-11 Transphyseal reconstruction is similar to the procedure performed in adults with standard bone tunnels that pass the physes. The use of standard tunnels provides reliable results, but carries the risk of iatrogenic growth disturbances from physeal injury.^6,9,12-14

In primary ACL reconstruction, allografts are comparable with autografts as equivalent clinical results show consistent efficacy.^15-17 Various allograft tissue types exist, including patellar, Achilles, tibialis, and peroneus longus tendons. Controversy exists in allograft selection about whether bone or soft tissue pass into physes. To the best of our knowledge, this is the first report of transphyseal ACL reconstruction using anterior tibialis allograft in skeletally immature patients in the English-speaking literature.

Case Report

Four girls 13.6 years or younger presented with injuries. Of the 4 patients, 2 were injured during athletic activites, 1 was injured in a motor vehicle accident, and 1 was injured due to a fall. Radiographs showed wide open physes. The patients underwent tibial and femoral transphyseal ACL reconstruction using anterior tibialis allografts. The patients’ ages ranged from 10.3 to 13.6 years, with a mean age of 12.4 years at the time of surgery. The mean duration of the operation was 103.8 minutes (range, 90-110 minutes), and mean bleeding amount was 33.8 cc (range, 30-40 cc). Three of 4 patients had midsubstance ACL tears and 1 had a femoral attachment site ACL tear on arthroscopy. One patient underwent concurrent partial meniscectomy due to a medial meniscus tear during ACL reconstruction.

All patients underwent a standard preoperative and postoperative evaluation that included a physical examination (Lachman test and pivot-shift test), whole scanogram, and standing AP, lateral, and patellar axial view radiographs. All patients had a complete radiolucency at the tibial and femoral physes (Figure 1). We evaluated physical and physiologic maturity according to the presence menarche onset in girls. None of the girls had reached menarche. One girl was in Tanner stage II and 3 were in Tanner stage III at the time of surgery. Height measurements were taken preoperatively and at most recent follow-up to assess growth. Magnetic resonance imaging was performed preoperatively on all patients to confirm the diagnosis of ACL disruption and to identify associated injuries, including meniscal tears.

Figure 1:Preoperative AP radiograph of ACL injury with wide open physes indicating the patient is skeletally immature.

All patients underwent transphyseal ACL reconstruction using anterior tibialis tendon allograft. Additional knee injuries were identified and additional procedures recorded. Eight mm bone tunnels were made through the proximal tibia and distal femoral physis. Grafts were placed in the over-the-top arthroscopic femoral tunnel point using the posterior aspect of the ACL footprint as a tibial guide at a 45° position. The free edge of the tibial tunnel was débrided, and a transtibial femoral offset guide positioned to leave a 1- to 2-mm back wall was hooked in the over-the-top position. A guidewire was placed and then overreamed with an EndoButton reamer (Smith and Nephew Endoscopy, Andover, Massachusetts). Anterior tibialis tendon allografts were prepared by whipstitching the proximal end and placing the graft over a 30- or 35-mm continuous-loop EndoButton under tension. The EndoButton and graft were brought through the tibial tunnel across the joint and through the femoral tunnel. Then the EndoButton was flipped, and tension was applied to the graft to assess its stability, after which the knee was fully extended to assess notch impingement (Figure 2). After that, tibial fixation was achieved with screws-and-washers in 3 cases and a biodegradable interference screw in 1 case (Figure 3).

Figure 2: On the second arthroscopy, 25 months after ACL reconstruction, no evidence of graft failure was found.

Figure 3: AP radiograph of a patient’s open distal femoral and proximal tibial physes 28.9 months postoperatively.

Postoperatively, the patient was allowed toe touch-down weight bearing as tolerated with the knee in an brace until quadriceps function returned and with early progression of range of motion and strengthening exercises as tolerated. Daily activity without a brace and crutch was allowed at 3 months postoperatively, and sports activity involving running and pivoting were permitted at 6 months postoperatively.

The mean postoperative duration of follow-up was 32.3 months (range, 27.8-37.5 months). No superficial or deep infections, deep vein thrombosis, nerve injury, arthrofibrosis, or other perioperative complications were found. None of the patients underwent revision reconstructions for graft failure.

At last follow-up, the results of the Lachman test were normal for 3 patients and nearly normal for 1 patient. All patients demonstrated full range of knee motion (comparing the reconstructed knee to the contralateral knee). The results of the pivot-shift test were normal for 3 patients and nearly normal for 1 patient. No patients reported giving way.

The mean modified Lysholm score was 96.8 (range, 94-99). The most common deduction scale on the score was slightly impaired squatting, which was demonstrated at last follow-up. Two patients reported slight pain during severe exertion.

The mean International Knee Documentation Committee subjective knee score was 92.2 (range, 88.5-95.4). All patients have returned to their preinjury level of activity and athletic participation. The score of the patient who reported nearly normal on the Lachman test and the pivot-shift examination was 90.8, but she had no limitations of activities of daily living and athletic participation except skiing due to fear of reinjury. None of the patients had angular deformities or early physeal arrest measured between preoperative and postoperative radiographs. No limb length discrepancies >1 cm clinically and radiographically were found (Figure 4).

Figure 4: Subclinical limb-length discrepancy (1 mm) measured by whole scanogram at last follow-up.

Discussion

There is controversy regarding the management of ACL injuries in patients with open physes. Nonoperative management of complete tears have a poor prognosis, with recurrent instability leading to further meniscal and chondral injury.^1,4,5,10 Similarly, when comparing the results of operative and nonoperative management of complete ACL injuries in adolescents, McCarroll et al¹⁵ and Pressman et al¹⁸ found that those managed with ACL reconstruction had less instability, higher levels of activity and return to sports, and lower rates of subsequent reinjury and meniscal tears.

Surgical treatment options for complete ACL tears include primary ligament repair, extraarticular tenodesis, transphyseal reconstruction, partial transphyseal reconstruction, and physeal-sparing reconstruction.^3-11,19 The advantage of transphyseal reconstruction is placement of the graft tissue in an isometric position to provide better results, according to literature reviews.^{1,6,9,12-14,20} The potential disadvantage is angular or limb-length discrepancy caused by physeal violation.^6,9,12-14 Kocher et al¹²reported 15 cases of growth disturbance: 8 cases of distal femoral valgus deformity with arrest of the lateral distal femoral physis, 3 cases of tibial recurvatum with arrest of the tibial tubercle apophysis, 2 cases of genu valgum without arrest, and 2 cases of leg-length discrepancy. But, multiple studies describe the use of this technique in >160 skeletally immature patients, with good results.^1,6,9,13,20

For the tunnel position and graft selection, the use of standard tunnels should be reserved for the skeletally immature patient nearing skeletal maturity and soft tissue graft is recommended to avoid physeal bar formation. McCarroll et al¹⁵ reported transphyseal ACL reconstruction using bone-patellar tendon-bone autograft. No postoperative angular deformities or limb-length discrepancies >1 cm were reported. Gaulrapp and Haus⁸ reported bone-patellar tendon-bone autograft and semitendinosus autograft for ACL reconstruction in skeletally immature patients. Both groups had a high rate of good to excellent results with no reported growth disturbances. Simonian et al²¹ believed that use of small, centrally placed tunnels and soft tissue grafts minimize the risk of physeal closure. Stadelmaier et al²²studied the effect of transphyseal drilling and soft tissue grafting across open growth plates duplicating ACL reconstruction in the canine model. They found that fascia lata placed in drill holes across open growth plates prevented formation of a bony bridge and found no histologic evidence of physeal arrest. These findings support transphyseal drilling with soft tissue grafting across open growth plates.

Allografts have been used for adult ACL reconstruction with acceptable success.¹⁷ Allograft tissue is an attractive alternative in the skeletally immature athlete because it avoids using autogenous tissue.^6,21Allograft tissue has certain advantages, including lack of donor-site morbidity and reduced operative time. In primary ACL reconstruction, allografts are comparable with autografts as equivalent clinical results show consistent efficacy.^15-17

However, allograft use for ACL reconstruction is a controversial issue. Borchers et al³ reported allograft use for ACL reconstruction as a risk factor for ACL graft failure and suggested that soft tissue allografts should be avoided in patients who desire a return to high activity level.

Various allograft tissue types exist including patellar, achilles, tibialis, and peroneus longus tendons, depending on the surgeon’s preference. Achilles tendon and bone-patellar tendon-bone allograft is useful, but bone tissue could affect physeal bar formation when the transphyseal technique was performed. Soft tissue grafts such as anterior tibialis and hamstring allograft could save operation time because the Endobutton technique is simpler than the interference screw fixation technique.

Transphyseal ACL reconstruction using anterior tibialis tendon allograft in skeletally immature patients provides considerable functional outcome with no growth disturbance.

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