Isolated Proximal Tibiofibular Joint Reconstruction With Semitendinosus Tendon Autograft in a Collegiate Athlete

Video Transcript

This video demonstrates an isolated proximal tibiofibular joint reconstruction with semitendinosus tendon autograft in a collegiate athlete.

Background

Instability of the proximal tibiofibular joint (PTFJ) is a rare condition, accounting for <1% of knee injuries. ³ It has long been recognized as a potential source of lateral knee pain and mechanical symptoms. Ogden's seminal work in 1974 defined the qualitative anatomy of the PTFJ and established a classification for PTFJ dislocations. ⁹ Most acute PTFJ injuries occur from high-energy trauma or sports, often involving a flexed knee with the foot plantarflexed and inverted, causing the fibular head to dislocate or sublux anterolaterally. ⁹ The PTFJ is stabilized by a robust anterior and a weaker posterior ligament complex. The anterior ligament of the PTFJ consists of up to 4 bands, whereas the posterior ligament has up to 3 bands. ¹ Furthermore, biomechanical testing has demonstrated that the posterior ligamentous complex has significantly lower failure load than the anterior ligamentous complex. ⁸ This relative weakness of the posterior restraints likely explains why anterolateral instability is by far the most common PTFJ injury pattern.

Conservative management is typically the first-line treatment for acute PTFJ instability. Initial measures include activity modification, bracing or taping of the fibular head, and short-term immobilization in extension. These measures can often reduce symptoms in the short term. However, chronic instability is common if the injury heals poorly, as up to 57% have been reported to continue to have pain or recurrent subluxation despite conservative therapy and ultimately require surgical intervention. ⁵ Currently, there is no universal consensus on the optimal surgical approach for PTFJ instability. In recent years, anatomic reconstruction techniques have been developed to restore native PTFJ stability.

Indications

We present the case of a 20-year-old male collegiate athlete with left knee pain due to PTFJ instability. He sustained an acute injury while playing basketball when another player landed on his back, forcing his flexed left knee into a twisting motion. He felt a “pop” in the posterolateral aspect of the knee and developed pain over the fibular head region. His symptoms improved slightly with rest, ice, and nonsteroidal anti-inflammatory drugs, but cutting and pivoting movements exacerbated the lateral knee pain and generated a sense of instability.

On physical examination 2 weeks after injury, the patient had no effusion with intact ligament examinations for the anterior cruciate ligament, posterior cruciate ligament, and collateral ligament, tested through the Lachman, pivot shift, posterior drawer, and valgus and varus stress tests. Notably, the left fibular head could be displaced anterolaterally relative to the lateral tibia when compared with the contralateral side, and there was tenderness over the peroneal nerve. Furthermore, there was 6 cm of heel height to 140° of flexion compared with 5 cm heel height to 140° of flexion contralaterally. The distal neurovascular examination was normal. These examination findings were consistent with left knee PTFJ instability.

Plain radiographs of the knee showed no fracture or dislocation, and bilateral alignment was neutral.

A magnetic resonance imaging of the left knee demonstrated bone marrow edema in the fibular head and adjacent lateral tibial plateau, as well as posterior soft tissue edema around the PTFJ, indicating injury of the posterior PTFJ ligaments. The cruciate and collateral ligaments and menisci were normal on imaging.

Given the acute injury (within 2 weeks) and the absence of gross joint dislocation, a trial of conservative management was pursued. The patient's knee was treated with PTFJ taping to stabilize the fibular head in a reduced position; he was allowed to weightbear in extension and instructed to modify activities. This diagnostic taping trial was continued for 6 weeks.^4,10

At the 6-week follow-up, the patient reported near-complete pain relief while his fibular head was taped, confirming that stabilizing the PTFJ alleviated his symptoms. However, the patient still had persistent instability and no signs of healing. There were no signs of peroneal nerve irritation throughout the trial. Given the upcoming American football season, the patient opted to continue nonoperative management (PTFJ taping for stability) and then proceed with surgical stabilization after the end of the college football season. Once the season ended, approximately 3 months after the injury, he returned for definitive operative treatment. The planned procedure was an isolated anatomic reconstruction of the PTFJ using an ipsilateral semitendinosus tendon autograft. Tendon graft reconstruction is preferred for chronic or high-demand cases to allow for anatomic restoration, early knee motion with little risk of stretching out of the reconstructed graft, and precise tensioning, whereas suspensory (suture-button) fixation can potentially be reserved for acute, lower-demand, or adjunctive situations.”^2,6,10

Technique Description

The procedure was performed under general anesthesia with the patient in the supine position. Instability of the fibular head was confirmed under anesthesia with increased anterolateral subluxation at approximately 90° of knee flexion compared with the contralateral limb. A high thigh tourniquet was applied to the operative limb, which was then prepped and draped in a standard sterile fashion.

First, a 4-cm vertical incision was made over the pes anserine bursa on the anteromedial proximal tibia. The semitendinosus tendon was isolated from the gracilis tendon, and adhesions were released. The semitendinosus tendon was then harvested proximally using an open hamstring harvester. The graft was detached from its tibial insertion, cleaned of muscle tissue, and both ends were whip-stitched using a No. 2 nonabsorbable suture.

An approximately 15-cm long lateral hockey stick incision was created proximally over the inferior iliotibial band and distally between the Gerdy tubercle and the fibular head. The subcutaneous tissue was incised to expose the iliotibial band and biceps femoris tendon. The common peroneal nerve was identified posterior to the biceps femoris tendon and mobilized via approximately 6 cm of neurolysis to ensure safe retraction throughout the case.

The PTFJ was accessed by elevating the anterior edge of the soleus off the posterior fibular head. The joint was debrided of scar and damaged ligament. A 2.4-mm guide pin was drilled, followed by a 6-mm reamer from anterolateral to posteromedial across the fibular head toward the posterior PTFJ footprint, with a posterior retractor protecting the common peroneal nerve. A suture passer was then used to shuttle a passing suture through the tunnel.

The tibial tunnel was started at the anterior “flat spot” distal and medial to the Gerdy tubercle and drilled posteromedially to exit just medial to the PTFJ and below the popliteus musculotendinous junction, in line with the fibular tunnel exit, and a 6-mm tunnel was reamed; a passing suture was inserted.

Standard diagnostic arthroscopy was performed via anterolateral and anteromedial portals. The patellofemoral and medial compartments were intact. In the lateral compartment, a small lateral femoral condyle impaction injury with unstable chondral flaps was treated with a chondroplasty. The menisci and cruciate ligaments were intact. Arthroscopy was ended, and joint fluid was evacuated.

The semitendinosus tendon autograft was passed anterior to posterior through the fibular head tunnel and fixed from the anterior side with a 7 × 20 mm bioabsorbable interference screw in the distal aspect of the tunnel to avoid a fracture of the proximal fibular head, which could be a concern with an anterior fixation screw. The graft was then passed from posterior to anterior through the tibial tunnel. With the PTFJ anatomically reduced with the knee positioned in 70° of flexion and neutral foot rotation, the graft was tensioned and fixed in the anterior aspect of the tibial tunnel using a second 7 × 20 mm bioabsorbable screw. Final assessment confirmed joint stability without subluxation.

The incisions were irrigated and closed in layers, and the patient was placed in a knee immobilizer in full extension.

Given the rarity of both PTFJ instability and this procedure, avoiding technical complications is of the utmost importance to ensure successful outcomes. One of the major concerns is iatrogenic injury, particularly to the neurovascular structures. During exposure, the common peroneal nerve should be identified and mobilized early to reduce the risk of a nerve palsy. Furthermore, as the tunnels are reamed, a retractor should be used to shield the posterior neurovascular bundle, and all drill trajectories should stay extra-articular to avoid cortical blowout. Graft harvest presents its own risks. Care must be taken to preserve the gracilis tendon and avoid violating the medial collateral ligament fibers to prevent iatrogenic damage while harvesting the semitendinosus tendon. To ensure proper graft tensioning, it is important to confirm rotational and translational stability intraoperatively with graft fixation. It is also important to ensure the knee is flexed to 70° during the final graft tensioning sequence, as this helps to reduce the PTFJ. Errors in tunnel positioning or fixation angle can result in persistent laxity or an overconstrained joint. Therefore, special attention should be paid to anatomical and radiographic landmarks to avoid preventable complications and optimize long-term outcomes. ⁷

Results

The patient was placed into a knee immobilizer immediately after surgery, and rehabilitation was initiated on postoperative day 1. For the first 2 weeks, the knee range of motion was restricted from 0° to 90° of flexion. After 2 weeks, a gradual increase in range of motion was allowed as tolerated. Weightbearing was limited to touch-down weightbearing (5 kg) for the first 6 weeks. Six weeks after the operation, the patient was allowed to initiate weightbearing as tolerated and weaned off crutches, provided he could walk without a limp. At approximately 4 months, isometric and isokinetic strength tests were performed to gauge recovery of the operative limb. Return to sport (RTS) was contingent on meeting rehabilitation milestones: (1) at least 85% strength of the injured leg compared with the contralateral side; (2) no pain or instability with sport-specific movements; and (3) clearance on clinical examination. This patient successfully met the RTS milestones, with a 100% of quadriceps limb symmetry index compared with the uninjured leg, and was cleared for sport at the 6.4-month follow-up.

Discussion/Conclusion

The systematic review by Kruckeberg et al ⁶ included 44 studies with 96 patients evaluating treatments for PTFJ instability. Surgical treatment showed better outcomes than nonoperative management, which had a 23% rate of persistent symptoms. Ligament reconstruction, especially biceps femoris tendon rerouting and anatomic grafts, had the best outcomes, with a 0% complication rate. Fixation using screws, K-wires/pins, or bone grafts was associated with a 28% complication rate, while fibular head resection had a 20% complication rate. Both techniques yielded less favorable outcomes. In contrast, reconstruction demonstrated the most consistent and effective results overall.

Furthermore, a case series by Dekker et al ² reviewed 15 patients who underwent reconstruction of the PTFJ using a semitendinosus tendon autograft for isolated instability. After a mean follow-up of 43.2 months, patients reported significant improvements in pain, function, and knee stability, as measured by both Western Ontario and McMaster Universities Osteoarthritis Index and Lysholm scores. Moreover, 85% of patients returned to their previous level of activity and sport. Two patients experienced complications: one had persistent common peroneal nerve pain that resolved with physical therapy and gabapentin, and another developed a transient femoral nerve palsy from a regional nerve block that resolved by 6 weeks postoperatively. The mean patient satisfaction score was 7.6 out of 10.

On postoperative day 1, the patient's knee was radiographically evaluated. Radiographs demonstrated that the interference screws were in good position and the bone tunnels in the fibular head and proximal tibia were anatomically placed, with no evidence of any iatrogenic fracture or hardware complications.