Abstract
Background:
Recurrent patellar instability is defined as ≥2 dislocation events or recurrence after surgical treatment. Surgical intervention is aimed at correcting pathoanatomic abnormalities. A tibial tubercle osteotomy (TTO) is an intervention that corrects patients with high tibial tuberosity-trochlear groove (TT-TG) distances and/or patella alta as measured by increased Caton-Deschamps index (CDI). Anteromedialization osteotomies improve abnormal TT-TG distances and offload the patellofemoral joint in patients with chondral lesions. Distalization can be utilized to correct patella alta and can be combined with anteromedialization osteotomies. We present a technique for TTO with medial patellofemoral ligament (MPFL) reconstruction (MPFLR) utilizing autograft gracilis tendon and knotless suture anchor fixation.
Indications:
Indications for a TTO with MPFLR include patients with recurrent patellar instability and increased TT-TG distance and/or increased CDI indicative of patella alta.
Technique Description:
Diagnostic arthroscopic examination of the knee is performed to assess chondral lesions of the patellofemoral joint. An anteromedial approach to the tibia is performed. The harvest of the autograft gracilis tendon is completed. TTO is performed based on the results of the preoperative examination and planning. Fixation is provided by two 4.5-mm stainless steel, solid screws in lag-by-technique mode. Two 1.4-mm knotless, all-suture anchors are then placed at the superomedial and midpoint of the patella after the approach. Schottle’s point is identified, and a tunnel is drilled for graft placement. The 2 limbs of the graft are passed between layers 2 and 3 after fixation. An interference screw is used for graft fixation within the tunnel. A repeat examination is performed to confirm patellar stability, and the incisions are then closed.
Results:
All-suture, knotless fixation of MPFL grafts has been shown in biomechanical studies to perform as well as knotted and knotless solid suture anchors when compared with overall load to failure and resistance to cyclic creep. The use of autograft hamstring in adolescents undergoing MPFLR shows no difference when compared with allograft.
Discussion/Conclusion:
Utilization of knotless all-suture anchors with autograft hamstring tendon in MPFLR with TTO presents an alternative to surgical fixation in patients with recurrent patellar instability.
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.
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Keywords
Video Transcript
We present a tibial tubercle osteotomy (TTO) with medial patellofemoral ligament reconstruction (MPFLR) using a hamstring autograft tendon.
Background
Patellar instability is a common problem evaluated by orthopaedic surgeons.4,10
The recurrence rate of patellar dislocations after an initial event is high, 9 especially in those patients <25 years.
Risk factors for recurrence include trochlear dysplasia, torsional alignment, and abnormal patellar tilt. 8
Surgical management is guided by correcting these abnormalities.1,5
Indications
This patient is a 15-year-old adolescent with a 2-year history of patellar instability after an initial dislocation event while playing soccer.
Physical examination is pertinent for 3-quadrant lateral glide at 15° to 20° of flexion with positive apprehension. He does have a positive J-sign.
Recurrent patellar instability is defined as ≥2 dislocation events or recurrence after surgical treatment. 3
TTO is recommended for patients with a tibial tuberosity-trochlear groove (TT-TG) distance of >15 mm; normal is <15 mm.
The Caton-Deschamps Index (CDI) has also been used as an indicator for TTO and can help guide preoperative planning based on the need for distalization. 7
Given this patient's presentation, he elected to proceed with a left knee diagnostic arthroscopy, TTO, and MPFLR utilizing a hamstring autograft.
This patient's TT-TG distance is measured at 15 mm.
A trochlear depth of 2 mm is indicative of trochlear dysplasia.
A CDI of 1.44 is indicative of patella alta. We, therefore, will plan for an anteromedialization osteotomy with 1 cm distalization to normalize the TT-TG distance and address patella alta.
An examination under anesthesia confirms the diagnosis, with a 3+ lateral patellar glide in extension and flexion.
Technique Description
The patient is positioned in the supine position.
Incisions are drawn preoperatively after surface landmarks are identified.
Diagnostic arthroscopy is performed to assess patellofemoral articular lesions.
After exposure, the lateral retinacular tissue is released, allowing for medial translation of the patella during osteotomy.
The osteotomy is planned 7 cm from the distal insertion site of the patellar tendon.
A large, flat osteotome is used to mark the site of the osteotomy.
The anterior compartment fascia is released from the lateral crest of the tibia in line with the osteotomy defined earlier.
A lap sponge can help with hemostatic dissection of the anterior compartment.
A transverse incision is made superior to the pes anserine. Avoid excessive medial dissection to prevent iatrogenic injury to the medial collateral ligament.
Gently dissect at the corner of the sartorial fascial flap that has been created until a space opens, as seen here.
Adhesions to the gracilis autograft are freed before harvest.
Movement of the calf can be used as an indicator of residual adhesions
Here, we see no movement of the calf after further release.
The gracilis autograft is whipstitched with a No. 2 FiberWire suture (Arthrex).
The knee is then flexed to about 90° to aid in hamstring harvest.
An open-loop tendon stripper is then used to harvest our gracilis tendon autograft. It is important to push the tendon harvesting device as opposed to pulling the graft to avoid truncation.
A red rubber catheter is then inserted at the harvest site, and 20 mL of 0.25% bupivacaine is injected to assist with postoperative pain control.
The sartorial fascia is then repaired with a 0 Vicryl suture.
A quarter-inch osteotome is used to create the lateral portion of the tapered cut. Maintain neutral alignment of the leg during this cut.
The transverse portion of the tapered cut is performed.
This is followed by the medial portion. The authors prefer this method to minimize fracture propagation into the tibial plateau.
A sagittal saw held at 45° is used to complete the osteotomy, slowly moving anteriorly as the cut is made distally.
The cut angle for anteromedialization is tailored to the osteotomy's goal. A flatter angle, providing more medialization, is used for instability. A steeper angle, providing more anteriorization, is used to unload the patellofemoral joint and reduce the degenerative process.
The cut is completed with an osteotome.
The osteotomy fragment is predrilled with a 4.5-mm drill for a lag-by-technique design.
The hard cortical bone of the distal osteotomy site is perforated multiple times with a 2.0-mm drill to optimize bony healing.
Because of the patient's patella alta, we preoperatively planned for about 1 cm of distalization with anteromedialization. A 1-cm cut is marked with electrocautery.
The distalization cut is then made.
A 2.0-mm K-wire is used to provisionally hold our osteotomized graft during fixation.
Repeat examination shows improved lateral glide, confirming appropriate correction.
A 3.2-mm drill is used to drill bicortically in the previously placed drill holes in the osteotomized fragment.
After measurement, a 4.5-mm solid stainless-steel screw is then placed to definitively affix the osteotomy.
Fluoroscopy is used to confirm the final position of screws.
Incision is made sharply with a scalpel.
After incision, electrocautery is used to carry out the dissection deep to the first layer of the medial knee.
The first layer of the knee is incised about 1 cm from the medial edge of the patella to allow for later closure.
A tonsil is used to clear the space between layer 2 and layer 3 of the knee.
Once a space has been created, the medial patella is cleared of soft tissue with electrocautery.
A rongeur is used until cancellous bone is reached.
A 1.4-mm knotless, all-suture anchor is drilled and inserted at the superomedial border of the patella.
A second anchor is inserted at the 50-yard line of the patella in a similar manner.
A tonsil is used to identify the position of the inferomedial incision over the Schottle point.
The Schottle point is identified under fluoroscopic guidance, and a beath pin is drilled bicortically through the lateral skin.
A 7-mm reamer is drilled unicortically.
The lateral cortex of the femur is then breached with a 4-mm drill bit.
Ethibond is passed anteriorly to be used as a passing suture.
A second Ethibond is passed through the graft tunnel to be used as a passing suture.
The authors prefer to leave the passing sutures laterally and the fixation suture medially for organization. The fixation suture is passed through the looped end of the passing suture after the midpoint of the graft is placed between the 2 anchors.
The nonlooped end of the suture is then pulled to pass the fixation suture.
The fixation suture is then appropriately tensioned to secure the graft to the patella.
This process is repeated for the other anchors, and the suture is appropriately tensioned to secure the gracilis autograft to the patella.
A 0 Vicryl suture is placed in a horizontal mattress fashion to further secure the graft to the patella.
The 2 ends of the gracilis autograft are passed between layers 2 and 3 utilizing the Ethibond suture.
The ends of the suture are passed into the graft tunnel along with a free suture.
The 2 limbs of the gracilis autograft are then guided into the graft tunnel.
Before fixation, the knee is cycled to determine the appropriate tension of the MPFL graft. The MPFL will usually be longest near full extension; thus, care must be taken with graft fixation not to overtension the graft, or the patient will have difficulty regaining full motion.
The graft is then fixed in place with an interference screw. The assistant maintains lateral restraint on the patella to prevent overtensioning of the graft.
Before final fixation, the driver is kept in the screw to allow tension adjustment if the reconstruction is too tight. Removing the screw without the driver risks damaging the graft. Once seated, the screw is often slightly reversed to avoid overtensioning.
Deep closure of layer 1 is performed with a 0 Vicryl suture.
Subcutaneous closure is completed with a 2-0 Vicryl suture.
Subcuticular closure is performed with a running 3-0 Prolene suture.
Results
The rehabilitation protocol is presented here. Return to sport is determined when the patient has a difference of <15% in several physiologic tests, as seen in the bottom right-hand corner.
Discussion/Conclusion
Biomechanical studies show that soft-body knotless anchors perform comparably to knotted and knotless solid suture anchors in load to failure and resistance to cyclic creep. 2
A retrospective study found no significant difference between allograft and autograft hamstring tendons in adolescent MPFLRs regarding return to activity, pain, or failure rates. Although allografts showed higher Kujala scores, the difference was not clinically meaningful. 6
Lastly, autograft has the added benefit of no extraneous cost when compared with allograft, as well as no risk for disease transmission in this young patient population.
Here are our references.
Thank you.
Footnotes
Submitted April 3, 2025; accepted August 17, 2025.
One or more of the authors has declared the following potential conflict of interest or source of funding: G.B. is a paid consultant for CONMED Linvatec and serves on committees for the American Orthopaedic Society for Sports Medicine (AOSSM). 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.
