INTRODUCTION
The anterior cruciate ligament (ACL) serves an important stabilising and biomechanical function for the knee joint. Rupture of the ACL leads to abnormal kinematics and predisposes the joint to degenerative changes. ACL reconstruction was previously considered inappropriate and unnecessary because results of surgery were unsatisfactory: patients treated surgically fared worse than those treated nonsurgically. Surgery could not restore normal function of the ligament and was fraught with numerous complications.
ACL reconstruction has been attempted using silver wire,1 fascia lata,2 and iliotibial band.3 In 1939, Campbell4 demonstrated reconstruction using the medial portion of the patellar tendon. In 1954, the development of a successful arthroscope brought new possibilities to the field of knee surgery.5 Arthroscopically assisted ACL reconstruction has the advantage of being minimally invasive. Grafts can be accurately placed and there is less disturbance of normal tissue. Subsequent recovery and rehabilitation are thus quicker.
Several types of replacement material are available: bone-patellar tendon-bone graft, quadrupled hamstrings, allografts, and synthetic materials. The patella tendon autograft has proved to be a reliable substitute for the native ligament and has yielded good long-term results. We report our experience of the first 100 cases of arthroscopically assisted ACL reconstruction using bone-patellar tendon-bone autograft.
MATERIALS AND METHODS
The study was conducted at the Central Institute of Orthopaedics, Safdarjung Hospital, India between April 2000 and February 2004. Patients with ACLdeficient knees who were symptomatic and wished to maintain an active lifestyle or continue sporting activities were recruited to the study. Patients were excluded if there were associated fractures around the knee, posterior cruciate ligament injury, or if they did not wish to maintain an active lifestyle. The study was approved by the ethics committee of our institute, and informed consent was obtained from all patients.
ACL reconstruction using the bone-patellar tendon-bone graft was performed in 100 patients during the study period. One-year follow-up was completed by 78, and 22 were lost to follow-up. The mean age of the 78 patients was 26.8 years (range, 21-39 years), 35 (44.9%) were aged 26 to 30 years. There were 73 men and 5 women (ratio, 14.6:1). Injuries to the right side (n=44, 56.4%) outnumbered those to the left (n=34, 43.6%) [ratio, 1.29:1]. Injury caused by sporting activities accounted for 66.7% (n=52) of the patients, whereas motor vehicle accident and household injuries accounted for 30.8% (n=24) and 2.7% (n=2), respectively. Football was the most common cause of injury (n=25, 32.1%), followed by cricket (n=13,16.7%).
Clinical examination was the mainstay for the preoperative diagnosis. Radiographs were obtained in 2 planes in the standing position. Magnetic resonance imaging (MRI) was restricted to patients in whom the diagnosis was uncertain (n=10) or to those who could afford it (n=22).
Acute ACL ruptures were treated conservatively for at least 2 to 3 weeks prior to surgery. Surgery was performed after acute inflammation had resolved. Full range of motion and absence of extension lag was ensured in all patients by intense preoperative physiotherapy.
All patients were operated on under spinal or combined spinal-epidural anaethesia. Peri-operative prophylactic antibiotic cover was given with thirdgeneration cephalosporin parenterally. A pneumatic tourniquet was used, and the operated leg was draped free.
In cases of clearly defined ACL deficiency, the graft was harvested before diagnostic arthroscopy. This prevented extravasated fluid from distorting tissue planes, and the graft could be prepared as the diagnostic arthroscopy proceeded.
Graft harvesting
A skin incision was made from the lower pole of the patella to 2 cm below the tibial tuberosity and extended medially. The paratenon was cut in line with the incision, and the patellar tendon isolated. With the knee flexed to 45
Graft preparation
The edges of the graft were trimmed using a small nibbler to enable smooth passage through a No. 9 sizer. Two holes perpendicular to each other were drilled on the tibial plug and one on the femoral plug using a 2 mm drill bit. A No. 5 Ethibond suture (Ethicon, Johnson and Johnson, Westwood [MA], US) was threaded through each hole. The retropatellar fat was dissected off the tendinous portion using Mayo scissors (Geomed, Germany). The bone-tendon junction on the femoral side of the graft was marked using a sterile marking pen. The graft was then assembled on the graft workstation. The length of the graft and plugs were measured accurately and covered with a moist sponge.
Notch preparation
The ligamentum mucosum was excised together with all soft tissue on the lateral wall of the intercondylar notch. Most of the remaining ACL tissue was removed except for the tibial stump, because it was believed to enable proprioceptive function.
Notch plasty
Notch plasty was performed only in cases of stenotic notches of less than 20 mm or when Over-the-top' position was not visible. An arthroscopic burr or curette was used.
Tibial tunnel placement
An ACL tibial jig's hook was positioned via the anteromedial portal just anterior to the PCL and in the middle of the intercondylar notch in the coronal plane. The cannulated guide was then pressed against the tibial cortex 1.5 cm medial to the tubercle and 1 cm proximal to the pes anserinus tendons. A pin was drilled and observed arthroscopically as it entered the nominated site on the intercondylar region. A 9-mm cannulated reamer was used to prepare the tunnel over the guide pin.
Femoral tunnel placement
A femoral offset guide was used to position the guide pin 7 mm anterior to the 'over-the-top' position. A 9-mm reamer was used to create a footprint prior to the final reaming. This footprint was confirmed to be 2.5 mm anterior to the 'over-the-top' position, to prevent posterior blow-out. The final reaming was continued to a depth of 5 mm to 7 mm greater than the bone-plug length. The mouth of the tunnel was cleared of all soft tissue.
Graft placement and fixation
A 'beath' pin was drilled across both the tibial and femoral tunnels to exit through the anterolateral aspect of the thigh. The graft was threaded through this 'beath' pin with the femoral plug up. The 'beath' pin was withdrawn from the femoral side by gentle hammering, and the plug seated in the femoral tunnel. A 2-mm Kirschner's wire was placed into the femoral tunnel alongside the graft at 110° knee flexion. An interference screw was threaded over it arthroscopically to fix the graft. The knee was cycled 5 to 10 times while applying tension over the holding sutures. Tibial fixation was performed at 20° flexion using a 9-mm interference screw.
Postoperative management
A compression dressing and rigid knee brace were applied postoperatively. Partial weight bearing was encouraged and gradually increased. Full weight bearing was permitted 4 weeks postoperatively. An intensive rehabilitation programme was instituted to allow patients to resume sporting activities and to regain range of motion, muscle strength, and normal gait.
RESULTS
Evaluation was performed using a scoring scale proposed by Lysholm and Gillquist6 (Table 1). At one-year follow-up, knee function was considered excellent in 7 (9%) patients, good-to-excellent in 61 (78.2%) patients, and fair-to-good in 8 (10.3%) patients, based on the Lysholm knee score. Results were poor in 2 (2.6%) patients with other associated injuries (Table 2). Most patients (n=69,88.5%) achieved a good range of motion. Six (7.7%) patients had restriction of terminal extension, 3 (3.8%) had more than 15° loss of terminal flexion, and one (1.3%) had 10° to 90° flexion.
Most patients who underwent ACL reconstruction had associated injuries of the knee (Table 3). Only 18 (23.1%) had an isolated tear of the ACL.
During arthroscopic ACL reconstruction, meniscal tears were treated by partial meniscectomy. Collateral ligament tears were managed conservatively.
Instability was assessed at the final follow-up using the anterior drawer and Lachman test. The knee joint was considered unstable in 15 (19.2%) patients. A further 4 (5.1%) patients had clinically significant instability that interfered with their activities of daily living.
The most common complication was anterior knee pain (Table 4). Divergence of screw was the most common immediate complication (Fig. 1). Loss of full range of motion was present in 10 (12.8%) patients. Posterior blow out of the femur was managed by converting 2 incision techniques and fixing the femoral bone plug with a cortical screw (Fig. 2). If this failed, a second interference was used to provide additional stability.
DISCUSSION
Rupture of the ACL compromises the stability of the knee and leads to episodes of giving way, recurrent injury to the menisci, and premature degenerative changes.7,8 Arthroscopically assisted ACL reconstruction facilitates early recovery and rehabilitation, improves patient comfort, and allows an early return to pre-injury activity. Management of associated injuries can be carried out simultaneously.
The middle third of the patellar tendon autograft for ACL reconstruction can be readily procured and firmly fixed. It can tolerate the loads produced by an intensive rehabilitation programme.1' Fixation of bone plugs using interference screws provides sufficient stability to meet the demand of a vigorous postoperative protocol."1 It remains the gold standard for ACL reconstruction." This method allows intensive retraining of the knee soon after surgery.
66 cases of associated injuries occurred in the 78 patients in our series. The most common was medial meniscal injury (n=25, 37.9%), followed by medial collateral ligament tear (n=16,24.2%) (Table 3). Presence of associated injury is indicative of damage occurring at the time of initial insult as well as the predisposition to secondary damage in the ACLdeficient knee. Extensive bone bruises that could not be detected clinically or arthroscopically after the first injury were evident on MRI even in truly isolated ACL ruptures.12These associated injuries compromise the results of ACL reconstruction.
Based on the Lysholm and Gillquist scoring system,6 87.2% of the patients achieved excellent and good-to-excellent results. These results are comparable with those achieved following similar reconstruction procedures.13,14 The scoring system assigns 30 points each to categories of pain and instability during walking, running, or jumping as 2 of the largest shares. It corresponds well with patients' return to pre-injury level of activity. Results obtained using our technique were significantly better than direct repair,13 extra-articular procedure,16 and intraarticular prosthesis.17 There were no instances of postoperative infection in our series. The method described here has significant advantages over other methods where wide exposure may lead to disastrous infective sequalae.4 A magnified view obtained during arthroscopy leads to accurate tunnel and graft placement.
The advantages of the patellar tendon as a graft source are its strength and immediate stability provided by screw fixation. Prosthetic materials are expensive, prohibitively so for most Indian patients. Hamstrings (quadrupled semitendinosus or combined semitendinosus and gracilis) as a source of graft have the disadvantages of being elastic and failure to achieve immediate rigid fixation to bone. Residual anterior knee pain (n=18,23.1%) and loss of full range of motion (n=10, 12.8%) were 2 most common complications among our patients. Patients were instructed to start range-of-motion exercises on the day following surgery and early weight bearing to avoid these complications. There were no disruptions of the extensor mechanism or non-traumatic graft failure. The results obtained in patients with isolated ACL injuries and those with associated injuries were comparable, despite the theoretical risk of the latter having significantly poor results. This implies that ACL is a major determinant of knee function.
Complications were more frequent during early stage of the study when the procedure was first introduced at our institute. Infra-operative complications decreased over time, indicating improved surgical technique. Accurate tunnel placement through arthroscopy was a crucial step in the procedure to prevent posterior femoral blow out and graft impingement and to provide proper graft orientation. A significant technical drawback of this single incision technique was the inability to fully control femoral-screw divergence. However, the incidence of this complication was not high.
CONCLUSION
Carefully selected patients with ACL-deficient knees undergoing arthroscopically assisted reconstruction using bone-patellar tendon-bone autograft can expect consistent and reproducible surgical results. Early and intensive rehabilitation allows an earlier return to preoperative levels of activity. Satisfactory longterm results can be achieved as long as the surgeon is adept at performing this procedure. Residual anterior knee pain is a major complication.
© 2005 Western Pacific Orthopaedic Association Provided by ProQuest LLC. All Rights Reserved.
Source: Journal of Orthopaedic Surgery
