Rupture of the patellar tendon must be diagnosed urgently because reconstruction of the extensor mechanism produces better results when it is performed in acute conditions. Reconstruction of chronic extensor mechanism rupture on the contrary is very challenging. Several surgical techniques have been described using a variety of graft choices and fixation methods, but the optimal approach is still under debate. We report our experience of two cases of chronic patellar tendon rupture reconstruction using an Achilles tendon allograft reinforced by a vascularized ipsilateral semitendinosus tendon frame. The rapid functional recovery of the range of motion, only three months postoperatively, showed us that this reconstruction technique was effective.
Chronic patellar tendon rupture is an uncommon pathology that is debilitating for patients, and its treatment can present a challenge for the treating surgeon. There are various etiologies: posttraumatic, secondary to systemic inflammatory pathologies [
To date, there are few studies and little data regarding the late reconstruction of a ruptured extensor apparatus [
This article reports our original experience of two cases of late reconstruction of the patellar tendon using an Achilles tendon allograft with semitendinosus reinforcement.
Patient 1 was a 41-year-old male with a past history of a road traffic accident that resulted in a ruptured left patellar tendon. He was initially treated conservatively with splint immobilization. Our treatment took place four years after the initial trauma. The patient complained of chronic pain with no possibility of locking for full extension of his knee. The preoperative range of motion was rated at 5 degrees of flexion deformity and 130 degrees of flexion. In addition, active extension was impossible. No laxity in the frontal or sagittal plane was identified. The Caton Deschamps index measured 2.47 on the X-rays, and the patella was 9 cm from the anterior tibial tuberosity (ATT) (Figure
Preoperative X-rays (anteroposterior and lateral views) of patient 1: patella alta,
Preoperative MRI of patient 1: atrophy and poor tissue quality of the left quadriceps muscle.
Patient 2 was a 45-year-old male with a history of multiple injuries to his left knee. A road accident was responsible for a supra- and intercondylar fracture of the femur, managed with osteosynthesis and a supracondylar nail. The nail was removed two years later because of a conflict between the femoral nail and the patella. Secondary to this, he presented with sepsis requiring surgical revision for washing, and he was treated with antibiotic therapy. Subsequently, X-rays showed calcifications in the patellar tendon leading to knee stiffness. Following a fall, an intratendinous calcification fracture was responsible for rupture of the extensor mechanism. Our treatment came two months after the trauma. The range of motion was graded as no flexion deformity, no recurvatum, and 30 degrees of flexion, and active extension was impossible. The Caton Deschamps index measured 0.82 on the X-rays (Figure
Preoperative X-rays (anteroposterior and lateral views) of patient 2.
We decided to reconstruct their extensor apparatus using an Achilles tendon allograft reinforced by a semitendinosus frame. Both patients were informed that their history could be used to produce a scientific article. They provided their consent. Preoperatively, the range of motion was measured using a goniometer. The visual analog scale measured their pain. Our imaging workup included bilateral AP and lateral X-rays of the knees. The Caton Deschamps index [
The patients were positioned in the supine position with a knee-bar at 60 degrees of knee flexion. An air tourniquet was applied to the base of the limb at a pressure of 250 mmHg. General anesthesia was used for complete muscle relaxation, associated with a femoral nerve block. Antibiotic prophylaxis was administered. We used an anterior medial approach.
Preparation of the receiver site consisted of making a four-sided hole in the ATT: width 2 cm, height 4 cm, and depth 2 cm. A bone block that is too loose or too small can lead to increased risk of nonunion. We then created a patellar trench: width 1.5 cm and depth 1 cm, from the upper pole to the lower pole, on the anterior cortical.
We then prepared the Achilles tendon allograft by cutting the calcaneal block to fit the trench size created in the ATT.
Tibial fixation of the allograft was performed using two 4.5 mm metallic screws in the calcaneum block and two 18 mm wide U-type staples stabilizing the calcaneum block on the medial and lateral sides of the ATT. The Achilles tendon graft needs to be fixed in extension after the optimal patellar height is achieved by tensioning, under fluoroscopic visualization, while the knee is at 30 degrees of flexion. In order to obtain the optimal patellar height, patient 1 needed the quadriceps to be released; patient 2 did not. The quadriceps tendon was released by using a Cobb on the anterior cortical area of the femur and severing the medial and lateral patellar retinaculum. Patellar fixation was achieved by placing the tendinous part of the allograft in the patellar trench and securing it with transosseous stitches with FiberWire® Size 2 (Arthrex).
Once the allograft was attached to the tibia and patella, we split the excess tendon in the patella’s upper pole into two strands (Figure
Fixation of the calcaneal block on the ATT using two screws and two staples (A). Fixation of the Achilles tendon allograft in the patellar trench (B) and division of the rest of the tendon into two strands (C). Semitendinosus tendon harvesting (D).
Autologous homolateral semitendinosus was harvested, keeping its distal insertion to make a vascularized graft possible. It was fixed on both sides of the allograft with 0 absorbable stitches (Figure
Framing with the semitendinosus tendon. Suture of the two strands onto each other and around the patella after passing through the vastus medialis and vastus lateralis.
Both our patients were treated postoperatively with preventive antibiotic therapy while awaiting the various bacteriological results from samples taken from both the graft and the patients themselves. The results of the complete bacteriological analysis were returned at 2 weeks; these samples were sterile on day 15, making it possible to stop the antibiotic therapy.
Weight-bearing was authorized from day 1 with an extension splint. The splint was kept for 6 weeks. Rehabilitation started on day 1 and consisted of awakening the quadriceps and recovering mobility. Flexion was only allowed up to 30 degrees in the first three weeks.
For patient 1, the consultation four weeks after surgery revealed quadriceps contraction, but lock-in extension had not yet been acquired. The range of motion was rated at 60 degrees of flexion without flexion deformity or recurvatum. On the postoperative X-rays, the Caton Deschamps index was calculated at 2 (versus 2.47 preoperatively), and no material fixation failure was observed (Figure
Postoperative X-rays (anteroposterior and lateral views) for patient 1:
Active extension and locking.
We performed isokinetic strength evaluation using a dynamometer (Medimex, France), 18 months after surgery. The aim of isokinetic tests is to assess the strength of a muscle group in a dynamic way, by getting as close as possible to physiological work. Torque was gravity-corrected to 45 degrees of knee flexion. The knees were evaluated, beginning with the nonoperated side after providing instructions and with both verbal encouragements and visual feedback. After familiarization with the isokinetic movement (5 concentric submaximal repetitions at 240°/s), the patient was tested over 3 repetitions in the concentric mode at 60°/s followed by 5 concentric repetitions at 180°/s. Thirty seconds of rest was provided between the two series and 2 minutes between the two sides. The concentric strength peaks of the knee extensors assessed at the two angular velocities of 60 and 180 degrees per second were used as study parameters to calculate the quadriceps limb symmetry index using the following formula:
This test showed a significant deficit of 90% in left quadriceps strength (right quadriceps at 60°/sec: 142 Newton meters and at 180°/sec: 99 Newton meters vs. the left knee at 60°/sec and 180°/sec: 16 Newton meters for both).
For patient 2, at one month, knee locking was already acquired and there was no pain. Ranges of motion were rated at 50 degrees of flexion without flexion deformity or recurvatum. Motor testing of the quadriceps was 3/5. On the postoperative X-rays, the Caton Deschamps index was calculated at 0.85 (versus 0.82 preoperatively); no material fixation failure was observed (Figure
Postoperative X-rays of patient 2:
Finally, there were no skin or septic complications in either of our patients.
After chronic patellar tendon rupture, reconstruction of the extensor mechanism is an unusual and challenging surgical approach because of tissue retraction, patellar migration, quadriceps atrophy, and poor tissue quality. In a review article on extensor mechanism injuries, Pengas et al. [
The advantage of an Achilles tendon allogeneic transplant is that it provides the graft with good tissue and bone quality in patients whose tissues are particularly fragile. Lamberti et al. demonstrated in their recent article that allografts in general, and Achilles tendon allografts in particular, provided better functional results than autografts in restoring correct joint function following total knee arthroplasty [
Our technique also has the advantage of using several fixation methods: an Achilles allograft, a hamstring autograft, and FiberWire®.
Bone fixation was achieved using screws and staples, to which we added an autograft of cancellous bone. Under these conditions, we believe that this fixation provides good primary stability and may improve bone integration. Fixation of the tendinous part of the allograft to the patella, through the vastus medialis and vastus lateralis, is an essential part of our surgery. We believe that this makes possible better distribution of the forces and decreases the stress on the quadriceps muscle, the tissues of which are already damaged.
The advantage of our technique is also that there was framing of the semitendinosus. Adding this biological fixation made it possible to strengthen our fixation while avoiding the need for another surgery to remove the material used for the metallic framing. This biological framing should reinforce the reconstruction’s long-term stability, bearing in mind the risk of allograft resorption in the long term. As we can see in the case reported by Ginesin et al. [
In our study, the functional results were excellent. Both our patients recovered active extension at three months after surgery. Walking with technical assistance and immobilization with a splint was thus needed for less than two months. The range of motion in their knees is compatible with everyday activities from 0 degree to more than 90 degrees, and patellar alignment has been restored and maintained.
The main disadvantages of our technique are the risk of infection associated with using an allograft, the risk of patellar fracture, and the cost and availability of the allograft. Nevertheless, neither of our patients experienced any complications.
In patient 1, we failed to restore height to the patella. Studies have reported the benefits of continuous preoperative transpatellar traction in the bed plane [
In our study, we were confronted with two different cases because patient 1 presented with a patella alta, while patient 2 had a normal patellar height. Our primary goal was to restore continuity in the extensor mechanism, with good function. This is why we were not expecting to fully restore the patella height, and this was not our goal.
We identified quadriceps atrophy, and quadriceps muscle weakness persisted. This is consistent with the cases reported by Falconiero and Pallis [
Regarding the range of motion, while the second patient’s joint mobility was only 90 degrees of flexion at one year, it should be remembered that his preoperative mobility was only 30 degrees.
The data that support the findings of this study are available from the corresponding author, LR, upon reasonable request.
The patients gave informed consent for the publication of this paper, including all images and references.
The authors declare no conflicts of interest regarding the publication of this paper.