Tibial Tubercle Proximalization: A Novel Technique to Lengthen the Extensor Mechanism in Skeletally Mature Patients With Lateral Habitual Patellar Dislocations

Abstract

Background:A habitual patellar dislocation (HPD) is a rare condition in skeletally mature patients, especially for those with severe quadriceps contracture. Until now, no study has reported the effectiveness of tibial tubercle proximalization to lengthen the extensor mechanism in treating severe HPDs in skeletally mature patients.Purpose:To describe a novel comprehensive procedure that includes tibial tubercle proximalization, extensive lateral release, tibial tubercle medialization, and medial patellofemoral ligament (MPFL) reconstruction in treating severe HPDs in skeletally mature patients and to report its early clinical outcomes.Study Design:Case series; Level of evidence, 4.Methods:From January 2014 to May 2016, a total of 43 consecutive patients (47 knees) with HPDs were surgically treated at a single institution and were retrospectively reviewed. Among them, 11 skeletally mature patients (11 knees) with severe primary HPDs underwent the index comprehensive procedure. Results of patellar tracking were recorded preoperatively and at the final follow-up. The radiological assessment included radiographs in standard anteroposterior, true lateral, and axial views and computed tomography scans at full knee extension before surgery and at the final follow-up. Subjective patellofemoral function was evaluated with the Kujala functional score before the index procedure and at the final follow-up visit.Results:The 11 included patients were evaluated for a mean period of 34.9 months (range, 25-46 months). The mean knee flexion angle when the patella dislocated laterally was 25° (range, 10°-30°) preoperatively. Radiologically, there was a statistically significant improvement in the congruence angle, from 73.4° ± 17.0° preoperatively to –7.1° ± 5.8° postoperatively (P < .01) and in the lateral patellofemoral angle, from –65.6° ± 9.4° preoperatively to 6.1° ± 2.7° postoperatively (P < .01). The mean preoperative Kujala functional score was 42.9, and the mean postoperative Kujala functional score was 95.2 (P < .05). No patients reported a recurrence of patellar dislocation at the final follow-up visit.Conclusion:The novel comprehensive procedure, including tibial tubercle proximalization, extensive lateral release, tibial tubercle medialization, and MPFL reconstruction, effectively treated lateral HPDs in skeletally mature patients with severe quadriceps contracture.

Treatment of Chronic Dislocated Patella in a Skeletally Mature Down Syndrome Patient

“…LL was performed to release the tight LR and was combined with MPFLR to achieve normal realignment of the patella to prevent patellar malalignment and hypermobility postoperatively. LL was also performed in combination with PTT 15 , a form of extensor mechanism release, to lengthen the extensor mechanism and decompress the contracted lateral components to allow remedialization of the patella.…”

“…Our postoperative protocol 15 uses knee brace in extension with partial weight-bearing for 6 weeks, followed by isometric quadriceps strengthening and allowance of knee flexion as tolerated by the patient.…”

“…There is no existing literature on the use of PTT in combination with MPFLR and lateral lengthening (LL) to treat habitual PFI in patients with DS as they represent a particular group of patients, although a recent study that used a combination of 4 procedures: MPFLR, tibial tubercle medialization, PTT for extensor lengthening, and lateral retinacular release (LRR) instead of LL, to treat habitual patellar dislocations caused by severe quadriceps contracture 15 showed good outcomes. Furthermore, specifically for PFI in patients with DS, existing literature only reports corrective surgeries being performed in skeletally immature children 2,9,16,17 instead of the adulthood (19-40 years) or senescence (>40 years) stages of DS 18 .…”

Surgical Technique for Obligate Flexion Patellar Dislocation: Medial Patellofemoral Ligament Reconstruction, Distal Femoral Osteotomy, Quadricepsplasty, and Lateral Retinacular Reconstruction with Dermal Allograft

“…Some have suggested using an osseous approach, a tibial tubercle proximalization, instead of a quadricepsplasty to limit scar tissue formation and allow for rigid fixation, enabling early postoperative rehabilitation. 25,26 However, this approach can be accompanied by complications and can further disrupt the delicate balance of patellofemoral forces and alternative anatomy, such as increasing patella alta, which can increase the risk of postoperative instability. Because of these risks, soft tissue reconstruction may be preferred.…”

“…30 Hung et al 31 reported excellent results in 56 of 76 knees (73.7%) that underwent reconstruction with iliotibial band with concomitant VY quadricepsplasty to improve knee flexion and patellar tracking. In addition, Song et al 25,32 reported the outcomes of 13 knees who underwent their "4-in-1" approach, which included a tibial tubercle proximalization and medialization, extensive lateral release, and MPFL reconstruction. The authors reported significant improvements in the Kujala score (from 41.4 to 94.9, P < .01) in addition to improvements in congruence angle and lateral patellofemoral angle.…”