Abstract
Background:
Patellar tendon ruptures presenting in a chronic setting are rare events that impose technical surgical challenges due to proximal retraction of the patella, quadriceps muscle atrophy and contracture, and peripatellar adhesions. Various reconstruction techniques have been described using different grafts and fixation methods; however, there is a paucity of reported outcomes and there is no consensus on standard of care.
Indications:
The patient is a 36-year-old man who presented with a failed patellar tendon reconstruction 14 months after his initial surgery (performed 1 year after the initial injury) with functional weakness and loss of extension. The patient was indicated for a revision patellar tendon reconstruction due to persistent functional limitations.
Technique Description:
The revision patellar tendon reconstruction was performed with gracilis and semitendinosus tendon autografts harvested from the ipsilateral limb. Hardware was removed from the initial graft tunnels in the tibial tubercle and patella. Patellar height was estimated using fluoroscopic measurement of the contralateral patellar tendon length. The graft is first passed through the patellar tunnel, and the individual limbs of the graft are then both placed through the tibial tubercle tunnel. A sternal wire in a figure-of-eight configuration was used to progressively distalize the patella to match the native patellar height, and the graft was then tensioned and secured together.
Results:
The patient regained full range of motion at 2-year follow-up and was able to return to work and activities without functional limitations. Recent case series also using ipsilateral hamstring tendon autograft for chronic patellar tendon reconstruction report improved patient outcome scores, normal Insall-Salvati index, improved quadriceps strength, and high levels of patient satisfaction.
Discussion/Conclusion:
Chronic patellar tendon ruptures are technically challenging to treat, especially in the context of revision of a failed reconstruction. The technique presented in this video may aid orthopaedic surgeons in treating this rare but debilitating injury. Given the lack of high-quality evidence, future studies are needed to explore graft choices, graft fixation techniques, and postoperative protocols.
Patient Consent Disclosure Statement:
The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.
This is a visual representation of the abstract.
Keywords
Video Transcript
In this video, we present a technique for the revision of a failed patellar tendon reconstruction using a hamstring tendon autograft.
These are our disclosures.
Patellar tendon ruptures, while relatively uncommon, affect less than 0.5% of the population each year, with greater prevalence among patients in their 30s to 40s. 9 Chronic conditions, including systemic lupus erythematosus, rheumatoid arthritis, chronic kidney disease, and diabetes mellitus, have been associated with patellar tendon rupture. While acute ruptures appear amenable to primary repair via transosseous tunnel or suture anchor fixation, chronic patellar tendon (CPT) ruptures (presenting >4 weeks after initial injury) can be challenging due to proximal retraction of the patella, quadriceps muscle atrophy and contracture, and peripatellar adhesions and thus may require reconstruction using either autograft or allograft techniques.1,4
Here, we present the case of a 36-year-old male truck driver with complaints of persistent functional weakness and loss of extension to his left knee over a year after a patellar tendon reconstruction. Two years prior, the patient sustained a noncontact injury while playing soccer. After initially deferring medical care, the patient underwent reconstruction using an anterior tibialis allograft 1 year after his initial injury. Despite 14 months of physical therapy (PT), the patient failed to functionally improve, at which time he presented to our clinic for a second opinion.
On physical examination, his patella is grossly seated in a relative proximal position. There is a palpable gap in the region of the patellar tendon. The patella can be manually translated distally into the trochlea. The range of motion (ROM) in the left knee is full extension to 135°. There is a 30° lag when active extension is attempted from a 90° position.
Radiographs show significant left patella alta. On the lateral view, the measured Caton-Deschamps index is 1.88 on the left compared with a normal value of 1.19 on the right. Notably, on the Merchant view, the trochlear space on the left side is absent of a patella due to its proximal positioning. A representative sagittal magnetic resonance imaging (MRI) cut demonstrates graft discontinuity consistent with disruption of the allograft.
The indication for reconstruction is functional disability and weakness secondary to disruption of the knee extensor mechanism from a failed reconstruction. There were no medical, surgical, soft tissue, rehabilitative, or social contraindications to the procedure performed on this patient. The patient was aware of the uncertain prognosis based on the limited literature related to his condition.
Several factors are considered in the preoperative plan. First, the surgeon must decide whether to stage the surgery. If the patella can be distalized, single-stage approaches involve stretching the quadriceps tendon and Z-shortening or lengthening of the patellar tendon. 8 However, if the patella is significantly retracted, a 2-stage technique may be necessary to first distalize the patella prior to reconstruction. Some techniques described in the literature include trans-skeletal traction or an external fixator followed by a secondary reconstruction.3,6
An additional preoperative consideration is graft selection. Both autograft and allograft have been described in the literature with favorable outcomes; however, there is a lack of strong evidence to suggest optimal graft choice. 4 The most commonly described reconstruction involves a hamstring tendon autograft using ipsilateral semitendinosus and/or gracilis tendon. Other techniques include vastus lateralis fascia, quadriceps tendon with patellar bone block, Achilles tendon, or contralateral bone-patellar tendon-bone grafts. 4 The method of graft fixation is a further consideration. Several methods are described, including transosseous sutures or tunnels, staples, suture anchors, and interference screws. Finally, cerclage wires or other hardware may be used to protect the reconstruction while healing by reducing the load on the graft postoperatively. 10
Moving to the case. The patient is positioned supine. A high thigh tourniquet is applied and fluoroscopy is used during the procedure.
At the start of the case, the contralateral, uninjured knee is imaged with fluoroscopy to determine the native patellar tendon length with the knee resting in 30° of flexion on a radiolucent triangle. Using a K-wire alongside the patellar tendon and manual measurement with a ruler, the estimated baseline patellar tendon length is measured.
Next, the ipsilateral hamstring graft is harvested. A gracilis and semitendinosis autograft is obtained, which measure approximately 25 and 28 cm in length, respectively. The combined diameter is 6 mm.
The distal two-thirds of the patient’s previous anterior incision is used to access the knee. The previous 7.5-mm tibial tubercle tunnel is identified, and 2 nonabsorbable interference screws are removed. No graft is noted to be entering the tunnel, but rather a white chalky material is visualized concerning for necrosis of the graft. The residual graft is resected from the surrounding soft tissue up to the patella where the previous 7.5-mm patellar tunnel is also identified. A 6-mm reamer is used in both tunnels to clear soft tissue graft. For demonstration purposes and improved visualization, we perform this technique on a cadaveric specimen. Here, we visualize the approximate placement of the tunnels.
Next, the leg is placed in full extension and the graft is first passed through the patellar tunnels and the individual limbs of the graft are then both placed through the tibial tubercle tunnel. Fluoroscopy is used to confirm appropriate distalization of the patella. The passage of the hamstring autograft is shown on the cadaveric knee.
This is a view of the knee after the graft has been passed through both patellar and tibial tunnels.
Next, a #7 sternal wire is placed through the quadriceps tendon at the superior pole of the patella. A 2-mm-diameter tunnel is drilled transversely across the tibial tubercle, just distal to the prior graft tunnel, and another sternal wire is placed through this tunnel. We then create a figure-of-eight with the 2 sets of wires, which are then tensioned to distalize the patella until the tendon length is equivalent to the contralateral knee. In the actual procedure, this step was performed prior to the passage of the graft as the patella was significantly retracted and needed to be distalized first.
Final tensioning of the graft is performed and its limbs are sutured together. ROM is assessed. The knee is flexed from approximately 0° to 60° with appropriate patellar tracking. The incision is closed, and the patient is immobilized in full extension with a knee immobilizer.
Here, a comparison of the final constructs is shown. On the left is an intraoperative image from the procedure prior to closing, and on the right is a fluoroscopic lateral image, which allows us to appreciate the restored patellar height.
Two-week postoperative radiographs show normalization of patellar height, with a Caton-Deschamps index of 1.19 on the left knee, improved from 1.88. The patient is placed in a hinged knee brace locked in extension and allowed full weightbearing. He is instructed to unlock the brace to 30° to perform rolling chair flexion. Finally, he is instructed to perform isometric quadriceps exercises and ankle pumps. In addition, PT protocol at this time includes active hip exercises.
Eight weeks postoperatively, the patient can flex his knee to 50° and he is instructed to slowly increase his ROM with PT. From the 3- to 6-month mark, the patient recovers well, and his ROM improves from 50° to 90° of flexion.
Subsequently, the patient is lost to follow-up due to the COVID-19 pandemic and not seen again until 16 months postoperatively. At this point, he has returned to work, but reports that his ROM had not progressed beyond 90° of flexion, causing significant limitations to his activities of daily living. Given the present limitations, the patient elects to undergo a left knee arthroscopy with lysis of adhesions. The procedure is performed without complications and his intraoperative passive flexion increases to 120°.
Six weeks status after left knee arthroscopy and 18 months status after revision of the left patellar tendon reconstruction, radiographs show unchanged patellar height. The patient is showing remarkable improvement with knee flexion to 130° and active extension without lag. The patient starts PT 2 weeks postoperatively, without ROM restrictions. PT protocol includes active-assisted ROM and quadriceps strengthening exercises. Overall, he is very satisfied with his outcome.
Some of the risks and complications associated with the procedure include graft failure, fracture of the patella, extensor mechanism weakness/atrophy, knee stiffness, symptomatic hardware, and wound complications. 4 Graft failure can be mimimized by appropriate graft selection. The graft must also be appropriately tensioned. Fluoroscopy aids with graft tensioning and patella positioning. If autograft tissue is inadequate, it may be augmented with allograft. To avoid knee stiffness and quadriceps atrophy, compliance with postoperative rehabilitation is vital to restore ROM and quadriceps strength. Hardware-related complications can be mitigated with the use of newer implants such as suture tape and anchors for graft protection and augmentation.5,11
There is no standardized postoperative protocol for patients undergoing reconstruction of a CPT rupture, nor is there strong evidence on best practices. However, certain steps can be taken to aid in rehabilitation and appear to lead to successful outcomes. The knee is generally immobilized immediately postoperatively to protect the construct. PT is then initiated to aid with ROM and to minimize stiffness and weakness while trying to avoid activities and motions that can stress the graft. A hinged knee brace that can be alternatively locked and unlocked for controlled periods of motion may aid in protecting the surgical reconstruction while simultaneously allowing a progressive increase in the ROM. Return to sports should be tailored to each patient based on individual recovery, sports, level of play, and other relevant factors.
Due to the rarity of this injury, there is a paucity of literature on standardized and objective outcomes after CPT reconstruction. When comparing acute versus CPT ruptures, Belhaj et al 2 found that while knee function and pain scores improved in both groups, the postoperative ROM was worse in patients with chronic ruptures at a median of 75 months. A systematic review by Gilmore et al 4 found that autogenous grafts were significantly better than primary repair; however, these conclusions were derived from an exceedingly small sample. In a case series of 13 patients who underwent CPT reconstruction using an ipsilateral hamstring tendon autograft, Valianatos et al 12 reported that, at a mean follow-up of 6 years, the mean Lysholm scores improved, the mean Insall-Salvati index was 1.2, and quadriceps power improved, without any reports of complications. Similarly, Maffulli et al 7 described 19 patients who underwent reconstruction using ipsilateral hamstring tendon. At 5.8-year follow-up, they found improved Kujala scores, normal Insall-Salvati index, quadriceps muscle volume was lower in the operative leg when compared with contralateral leg, 13 of 19 patients returned to sport, and almost 90% reported satisfaction with the procedure. Given the lack of high-quality evidence, future studies are needed to explore graft choices, graft fixation techniques, and postoperative protocols.
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Footnotes
Submitted February 16, 2023; accepted June 9, 2023.
One or more of the authors has declared the following potential conflict of interest or source of funding: E.A. has received support for education from Gotham Surgical Solutions & Devices. G.J.A. has received support for education from Gotham Surgical Solutions & Devices. M.J.M. receives speaking fees from Smith & Nephew. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
