Tibiofemoral rotation in patellofemoral pathology: a systematic review of imaging modalities, measurement techniques and clinical relevance.

Knee Bracing after Medial Patellofemoral Ligament Reconstruction: A Systematic Review of Protocols and Postoperative Outcomes

Abstract Medial patellofemoral ligament reconstruction (MPFLr) is the most common procedure performed for recurrent patellar instability. Although the benefits of MPFLr are well-established, postoperative bracing protocols remain highly variable and poorly characterized in the current literature. The purpose of this study was to evaluate the use of bracing by sports medicine surgeons for patients following MPFLr. Randomized controlled trials, prospective, and retrospective studies of patellar instability treated with MPFLr were identified across three databases: EMBASE (Elsevier), Medline (OVID), and SportDiscus with Full Text (EBSCOHost). Study quality was assessed using established risk of bias tools; several studies demonstrated moderate risk of bias due to nonrandom selection of intervention groups and variability in rehabilitation. Data collected included functional outcomes and rates of redislocation or subluxation. Of 521 studies identified, 112 duplicates were removed. Abstracts of 409 studies were reviewed, with 348 excluded for relevance. Full-text review of 61 studies yielded seven meeting inclusion criteria, all of which included postoperative rehabilitation protocols. Five studies (71.4%) used knee braces postoperatively, and two (28.6%) compared postoperative bracing to no bracing. Four studies (57.1%) reported using a hinged knee brace and two (28.6%) used a knee immobilizer. Six of seven studies (85.7%) braced patients for up to 6 weeks postoperatively. Postoperative instability events were reported in six studies (85.7%), collectively encompassing 650 knees. Bracing was applied to 533 knees, of which 25 (4.7%) experienced at least one instability event, compared with 1 of 117 nonbraced knees (0.9%). There was no statistically significant difference in instability events between groups (χ 2 [1, N  = 650] = 3.68, p  = 0.055). Most sports medicine surgeons brace patients for up to 6 weeks following MPFLr. Bracing protocols are widely variable, and current studies exhibit marked heterogeneity in reporting of postoperative outcomes. Further research is needed to determine the optimal postoperative rehabilitation protocol, including the use of a hinged knee brace, following MPFLr.

MEDIAL PATELLOFEMORAL LIGAMENT SURGERY IN THE PEDIATRIC POPULATION: A LITERATURE REVIEW ON THE CURRENT STATE OF THE ART

Magnetic Resonance Imaging Enables Precise Quantification of Patellar Height and Engagement in Patients Undergoing Tibial Tubercle Distalization Osteotomy for Objective Patellar Instability.

INTRODUCTION The objective of this study is to evaluate the improvements in patellar height and the amount of correction of Caton-Deschamps index (CDI), patellar height index (PHI), and sagittal patellofemoral engagement (SPE) after surgery of tibial tubercle osteotomy (TTO) and medial patellofemoral ligament (MPFL) reconstruction for objective patella instability (OPI) associated with patella alta. METHODS A consecutive series of TTO and MPFL reconstruction between 2021 and 2023 were prospectively enrolled. All patients underwent pre-operative and post-operatively (7 months) X-rays and Magnetic resonance imaging (MRI). Imageries were reviewed by three independent reviewers to measured CDI, PHI and SPE. RESULTS A total of 50 patients were enrolled in this study (mean age: 22.2 ± 7.2 years; 48% male). The mean tibial distalization was 6.7 mm ± 2.7. CDI decreased from 1.25 ± 0.2 to 0.97 ± 0.1 (p < 0.001). PHI improved from 1.28 ± 0.2 (mean ± SD) to 1.04 ± 0.19 (p < 0.001), and SPE from 31% ± 18.7 to 60% ± 13.5 (p < 0.001). CONCLUSION A standardized MRI protocol allows reproducible quantitative assessment of patellar height and sagittal patellofemoral engagement following distalization TTO. LEVEL OF EVIDENCE IV.

Medial Quadriceps Tendon-Femoral Ligament Reconstruction Offers Favorable Clinical Outcomes and Low Complication Rates for Recurrent Patellar Instability: A Systematic Review.

PURPOSE To evaluate the surgical methods, clinical outcomes, and complication profile of patients undergoing medial quadriceps tendon-femoral ligament reconstruction (MQTFLR), either isolated or as medial patellofemoral complex reconstruction (MPFCR), for recurrent patellar instability. METHODS Three databases (PubMed, EMBASE, and MEDLINE) were searched on July 28, 2025, for clinical studies assessing patient outcomes following MQTFLR with or without concurrent medial patellofemoral ligament reconstruction (MPFLR). Data on functional outcomes including Kujala scores, International Knee Documentation Committee (IKDC) scores, Lysholm scores, Tegner score, and visual analog scale scores were collected, along with return to sport, redislocation rates, revisions, and other complications. The Methodological Index for Non-Randomized Studies criteria were used to assess study quality. RESULTS Nine studies comprising 347 patients (68.3% female, mean age 18.6 years (range: 12.2-29.0)) were included. Combined MQTFLR + MPFLR (MPFCR) showed favorable Kujala scores (range 85.9-93.6), IKDC scores (range 81.5-91.2), Lysholm scores (range 84.3-93.3), and moderate Tegner scores (4.6-6.0). Among MPFCR patients with available minimum clinically important difference data, the minimum clinically important difference was achieved in 61/61 knees (100%) for Kujala, 97/103 knees (94.1%) for IKDC, 60/61 knees (98.1%) for Lysholm, and 44/61 knees (72.1%) for Tegner. The IKDC patient acceptable symptom state score was surpassed by 28/42 knees (66.7%). Patients undergoing MPFCR were found to have a high return to sport rate (88.5%-100%) and a low redislocation rate (1.6%). The single major complication was arthrofibrosis in 2 patients. Isolated MQTFLR and isolated MPFLR both showed comparable functional outcomes, but a higher rate of complications such as arthrofibrosis, flexion limitation, and patellar fracture compared with patients who underwent MPFCR. CONCLUSIONS MQTFLR in combination with MPFLR (MPFCR) is a viable option for surgical management of patellofemoral instability, with favorable clinical outcomes supporting its use. LEVEL OF EVIDENCE Level IV, systematic review of Level III and IV studies.

Magnetic Resonance Imaging Evaluation of Patellofemoral Instability with Emphasis on Tibial Tuberosity-Trochlear Groove Ratio: A Case Series.

ABSTRACT Patellar instability is a multifactorial condition influenced by trochlear morphology, patellar height, extensor mechanism alignment, and soft tissue integrity. The tibial tuberosity-trochlear groove (TT-TG) distance is commonly used to assess lateralization; however, borderline values remain difficult to interpret. The TT-TG ratio has been proposed as a normalized parameter to improve assessment. Our aim was to evaluate magnetic resonance imaging (MRI) based parameters of patellofemoral instability with emphasis on the role of the TT-TG ratio in interpreting borderline TT-TG values. This retrospective case series included three patients with clinically suspected patellar dislocation who underwent MRI evaluation. Parameters assessed included trochlear morphology (trochlear depth, lateral trochlear inclination, and sulcus angle), patellar height (Insall-Salvati ratio [ISR] and Caton-Deschamps index), patellar alignment (patellar tilt angle and bisect offset), and extensor mechanism alignment (TT-TG distance and TT-TG ratio). Soft tissue structures, including the medial patellofemoral ligament, were also evaluated. Two patients had recurrent dislocation following trivial trauma, while one had acute dislocation after significant trauma. Borderline trochlear morphology was observed in two cases. One patient demonstrated patella alta based on ISR. All cases showed lateral patellar maltracking. TT-TG distance ranged from 13 to 19.5 mm (normal to borderline), whereas TT-TG ratio ranged from 0.20 to 0.26, with one case showing abnormal lateralization. Higher TT-TG ratios corresponded with increased bisect offset and greater lateral patellar displacement. These findings suggest that patellar instability results from a combination of anatomical and biomechanical factors. The TT-TG ratio demonstrated a better correlation with lateral patellar maltracking compared to absolute TT-TG distance, particularly in borderline cases.

Isolated Medial Patellofemoral Ligament Reconstruction Reduces Patellar Height and Is Associated With Quadriceps Dysfunction.

PURPOSE To assess whether isolated double-limbed medial patellofemoral ligament reconstruction (MPFLR) affects patellar height, measured via the Caton-Deschamps Index (CDI), and determine association with preoperative patella alta and postoperative quadriceps dysfunction. METHODS A retrospective review was performed on subjects that underwent isolated MPFLR from 2016 to 2022. INCLUSION CRITERIA age 13 to 62 years, patellofemoral instability, no prior ipsilateral surgery, and no bony procedures. CDI was measured on standardized perfect lateral radiographs. The first available preoperative perfect lateral radiograph and the first available postoperative perfect lateral radiograph closest to the date of surgery were used for analysis. Patella alta was defined as CDI > 1.2. Quadriceps function was assessed by straight leg raise postoperatively at the same time of the first postoperative perfect lateral radiograph. Statistical tests included Wilcoxon signed-rank, Mann-Whitney U, and linear regression. RESULTS Eighty-one knees were included (mean age 21.0 ± 8.7 years, 62% female). Postoperative radiographs were obtained a mean of 38.78 ± 58.18 (1-351) days after surgery. Mean CDI decreased significantly following MPFLR. Patients with preoperative patella alta showed greater reduction in CDI compared with those without patella alta, and increasing preoperative CDI was weakly but significantly associated with greater CDI change. CDI reduction varied by postoperative quadriceps function, with progressively larger decreases observed in patients with extensor lag or inability to perform straight leg raise. Among patients with extensor lag, those with higher preoperative CDI experienced significantly greater CDI reduction. CONCLUSIONS Isolated double-limbed MPFLR significantly reduces patellar height, with a CDI reduction of about 0.05 even with good quadriceps function. However, larger early postoperative decreases in CDI are likely artificial, reflecting transient quadriceps inhibition rather than true distalization of the patella. LEVEL OF EVIDENCE Level IV, retrospective case series.