Influence of patient-related factors on clinical outcome of tibial tubercle transfer combined with medial patellofemoral ligament reconstruction

Derotational distal femur osteotomy with medial patellofemoral ligament reconstruction can get good outcomes in the treatment of recurrent patellar dislocation with excessive TT-TG and increased femoral anteversion

Background

Surgery is the main treatment for recurrent patellar dislocation (PD). However, due to the complexity of anatomical factors, there is still a lack of consensus on the choice of combined surgical methods. This study aimed to compare the clinical and radiological outcomes of medial patellofemoral ligament reconstruction combined with derotational distal femur osteotomies (MPFLR + DDFO) and combined with tibial tubercle osteotomies (MPFLR + TTO) for recurrent PD with increased femoral anteversion angles (FAA) and excessive tibial tubercle-trochlear groove (TT-TG) distance.

Methods

In this retrospective analysis, MPFLR + DDFO and MPFLR + TTO patients from 2015 to 2020 were included. Group A (MPFLR + DDFO, n = 42) and B (MPFLR + TTO, n = 46) were formed. Clinical outcomes included physical examinations, functional outcomes (Kujala, Lysholm, International Knee Documentation Committee (IKDC), visual analog scale (VAS) and intermittent and persistent osteoarthritis pain scale (ICOAP), Tegner scores), and complications. The Caton-Deschamps index (CD-I), patellar title angle, patellar congruence angle, patella-trochlear groove distance, TT-TG distance, and FAA were used to assess radiological outcomes.

Results

All clinical outcomes improved significantly in both groups, but Group A had significantly better postoperative scores than Group B (Kujala: 89.8 ± 6.4 vs. 82.9 ± 7.4, P < 0.01; Lysholm: 90.9 ± 5.1 vs. 81.3 ± 6.3, P = 0.02; IKDC: 87.3 ± 9.0 vs. 82.7 ± 8.0, P < 0.01; Tegner: 6.0 (5.0, 9.0) vs. 5.0 (4.0, 8.0), P = 0.01). However, there was no significant difference in the VAS and ICOAP scores between the two groups. No dislocation recurrences occurred. Radiological outcomes improved significantly in both groups, but Group A had better outcomes. After surgery, the patellar height of 88.5% (23/26) patients in Group A and 82.8% (24/29) patients in Group B was restored to normal (the Caton-Deschamps index <1.2).

Conclusions

Both MPFLR + TTO and MPFLR + DDFO obtained satisfactory clinical and radiological outcomes in the treatment of recurrent PD with increased FAA and excessive TT-TG. However, the outcomes of MPFLR + DDFO were better and should be considered a priority. MPFLR + TTO may be not necessary for such patients.

MPFL Reconstruction Combined with a Modified Elmslie-Trillat Procedure for Recurrent Patellofemoral Instability

Several combined procedures have been reported for treating recurrent patellofemoral instability (RPI) with various types and severity of morphological abnormalities, but none have identified absolute threshold values as indications for surgery. We performed medial patellofemoral ligament (MPFL) reconstruction combined with a modified Elmslie-Trillat (ET) procedure on 24 knees (10 male and 11 female patients) to treat RPI with morphological abnormalities corresponding to elevated tibial tubercle-trochlear groove (TT-TG) distance, significant patella alta, and trochlear dysplasia. The inclusion criteria were RPI with morphological abnormalities corresponding to one or more of the following: sulcus angle > 160 degrees, trochlear dysplasia of Dejour classification C or D, Caton-Deschamps index > 1.5, lateral shift ratio > 50%, congruence angle > 15 degrees, or TT-TG distance > 20 mm, including habitual dislocation of the patella. Skeletally immature patients and those with congenital dislocation of the patella were excluded. The Kujala score, International Knee Documentation Committee subjective score, Knee Injury and Osteoarthritis Outcome score (KOOS), and each item of the KOOS improved significantly after surgery. Patellar apprehension sign was present preoperatively in all cases, but all disappeared postoperatively. No instance of postoperative redislocation was observed. On radiographic examination, the mean Q angle, tilting angle, lateral shift ratio, congruence angle, Caton-Deschamps index, Insall-Salvati index, and TT-TG distance improved significantly after surgery. There were no significant differences in sulcus angle after surgery. These results suggest MPFL reconstruction combined with a modified ET procedure provides satisfactory outcomes based on radiological and clinical evaluations for RPI with morphological abnormalities corresponding to elevated TT-TG distance, significant patella alta, and trochlear dysplasia.

Patella alta and increased TT-TG distance do not adversely affect patient-reported outcomes following isolated MPFL reconstruction: A systematic review

OBJECTIVES

To analyze the effect of patellofemoral anatomical variations (patella alta, increased tibial tubercle-trochlear groove [TT-TG] distance, and trochlear dysplasia) on clinical outcomes after isolated medial patellofemoral ligament (MPFL) reconstruction.

METHODS

A comprehensive search from PubMed, Embase, and the Cochrane Library databases was conducted to identify studies that compared outcomes based on the presence or absence of patella alta, elevated tibial tubercle-trochlear groove (TT-TG) distance, and/or trochlear dysplasia. Exclusion criteria included reviews and meta-analyses, studies that included patients who underwent associated bony procedures, and those reporting outcomes after isolated MPFL reconstruction with no comparison between varying anatomical groups.

RESULTS

After application of selection criteria, 19 studies were included. Patella alta was not predictive of failure or poorer outcomes among 13 studies; however, 2 studies demonstrated poorer patient-reported outcome scores and/or higher failure rates with increasing patellar height. Increasing TT-TG distance demonstrated a statistically significant correlation with poorer outcomes in only one study, whereas 12 other studies showed no association. Trochlear dysplasia resulted in worse outcomes and greater failure rates in 6 studies, while 10 studies showed no statistically significant correlation between trochlear dysplasia and postoperative outcomes.

CONCLUSION

Patella alta and increased TT-TG distance did not adversely affect outcomes following isolated MPFL reconstruction in the preponderance of reviewed studies. Data are mixed regarding the impact of trochlear dysplasia on the outcomes of isolated MPFL reconstruction.

LEVEL OF EVIDENCE

IV.

The remaining parameters of patellar instability could be affected for osteoarthritic change after medial patellofemoral ligament reconstruction with or without anteromedialization of the tibial tubercle osteotomy for patellar instability: a retrospective cohort study

BACKGROUND

In literature, studies evaluating the factors associated the postoperative progression of patellofemoral (PF) osteoarthritis (OA) following patellar stabilization surgery are limited. This study aimed to compare the clinical outcomes after medial patellofemoral ligament reconstruction (MPFLR) as an isolated procedure (iMPFLR) and in combination with anteromedialization (AMZ) of the tibial tubercle osteotomy (TTO) and investigate the factors related to the postoperative progression of PFOA after patellar stabilization surgery.

METHODS

Between 2009 and 2020, 30 knees of 23 consecutive patients underwent MPFLR with or without AMZ, using an autologous semitendinosus tendon graft; they were followed up for more than 2 years in the retrospective nature of the study. iMPFLR was performed in cases of recurrent patellar dislocation with normal tibial tubercle-trochlear groove (TT-TG) distance and no PFOA, and MPFLR+AMZ was performed for cases of excessive TT-TG distance, preoperative PFOA of recurrent patellar dislocation, or habitual patellar dislocation. Clinical findings and radiographs of the PF joint were evaluated pre- and postoperatively with PF alignment parameters and PFOA and were compared between surgical procedures. Factors for the postoperative progression of PFOA were compared between the OA progression and non-progression groups.

RESULTS

Postoperative clinical score, radiographic parameters except for sulcus angle, TT-TG distance, and progression of PFOA were not significantly different between the iMPFLR and MPFLR+AMZ groups. Postoperative lateral patellar displacement (p = 0.001) and congruence angle (p = 0.017) were significantly different between the OA progression and non-progression groups.

CONCLUSION

Similar to MPFLR for recurrent cases, MPFLR with AMZ can improve the clinical and radiographic outcomes in severe cases. The remaining parameters of patellar instability could be affected in the postoperative progression of PFOA after MPFL reconstruction with or without AMZ of TTO for patellar instability.

CT and MRI measurements of tibial tubercle lateralization in patients with patellar dislocation were not equivalent but could be interchangeable

PURPOSE

To compare the values and the relationship of tibial tubercle lateralization measurements between computerized tomography (CT) and magnetic resonance imaging (MRI).

METHODS

Sixty patients with patellar dislocation who underwent both CT and MRI of the same knee joint from November 2021 to February 2022 were included in our study. The intraclass correlation coefficient (ICC) and Bland-Altman analysis were performed to evaluate the reliability of tibial tubercle-trochlear groove (TT-TG), tibial tubercle-Roman arch (TT-RA), and tibial tubercle-posterior cruciate ligament (TT-PCL) distance measurements. The values of CT and MRI measurements using the same bony landmarks were compared for the difference. Pearson correlation analysis and linear regression analysis were performed to assess the correlation between CT and MRI measurements. Finally, the estimated values obtained from the regression equation were compared with the actual values obtained from the radiological measurement to evaluate the accuracy of the equations.

RESULTS

A total of 60 patients with patellar dislocation who underwent both CT and MRI of the same knee joint were included in this study. The included measurements showed excellent agreement with ICCs > 0.9. TT-TG distance measured on CT (19.5 ± 5.1 mm) had a mean of 7.1 mm higher than that on MRI (12.4 ± 4.7 mm) (P < 0.001). The mean value of TT-RA distance was 22.5 ± 3.7 mm on CT and 16.7 ± 4.9 mm on MRI (P < 0.001), showing a mean difference of 5.8 mm. The values of TT-TG distance measured by CT and MRI were significantly correlated (R = 0.5, P < 0.001). The values of TT-RA distance between these two modalities showed a better correlation than that of TT-TG distance (R = 0.6, P < 0.001). The interchange values of TT-TG distance and TT-RA distance between CT and MRI can be obtained using regression equations (TT-TG distance: y = 0.6x + 12.3; TT-RA distance: y = 0.5x + 14.4).

CONCLUSION

The values of tibial tubercle lateralization measured by MRI may be underestimated compared with those measured by CT. Although the values measured on CT and MRI are not equivalent, the value in the other modality can be estimated. Therefore, an additional CT scan for tibial tubercle lateralization evaluation may not be necessary.

LEVEL OF EVIDENCE

Level II.

The Influence of Surgical Realignment Procedures on Dynamic Patellar Tracking: A Dynamic Magnetic Resonance Imaging-Controlled Feasibility Study

Persisting patellar maltracking following surgical realignment often remains unseen. The aim of this study was to analyze the effects of realignment procedures on patellofemoral kinematics in patients with patellofemoral instability (PFI) and patellofemoral maltracking (PM) by using dynamic magnetic resonance imaging (MRI). Patients planned for surgical patellar realignment due to PFI and a clinically and radiologically apparent PM between December 2019 and May 2022 were included. Patients without PM, limited range of motion, joint effusion, or concomitant injuries were excluded. Dynamic mediolateral translation (dMPT) and patella tilt (dPT) were measured preoperatively and three months postoperatively. In 24 patients (7 men, 17 women; mean age 23.0 years), 10 tibial tubercle transfers, 5 soft tissue patella tendon transfers, 6 trochleoplasties, 3 lateral lengthenings, 1 varizating distal femoral osteotomy (DFO), and 1 torsional DFO were performed. At final follow-up, dMPT (from 10.95 ± 5.93 mm to 4.89 ± 0.40 mm, p < 0.001) and dPT (from 14.50° ± 10.33° to 8.44° ± 7.46°, p = 0.026) were significantly improved. All static radiological parameters were corrected to physiological values. Surgical patellar realignment contributed to the significant improvement of patellofemoral kinematics, with an approximation to normal values. The postoperative application of dynamic MRI allowed for a quantification of the performed correction, allowing for a postoperative control of success.

Return to Play Considerations After Patellar Instability

PURPOSE OF REVIEW

To discuss the treatment options and rehabilitation protocols after non-operative and operative treatment of patellar instability, and to discuss expected return to play outcomes and functional performance with non-operative and operative treatment of patellar instability.

RECENT FINDINGS

A criterion-based program assessing range of motion, joint effusion, strength, neuromuscular control, proprioception, agility, and power are critical measures to assess when rehabilitating this population. A series of functional tests including quadriceps strength testing, single-limb hop testing, lateral step-down test, the side hop test, the lateral leap and catch test, the Y-balance test, and the depth jump should be considered when determining an athlete's return to sport clearance. These objective measures combined with psychological readiness and a comprehensive understanding of the sports-specific tasks required for participation should be considered when evaluating an athlete's ability to safely and successfully return to sport. We discuss rehabilitation management when working with non-operative and operative management of patellar instability and provide considerations for clinicians working with these athletes to facilitate safe return to sport.

Isolated medial patellofemoral ligament reconstruction results in similar postoperative outcomes as medial patellofemoral ligament reconstruction and tibial-tubercle osteotomy: a systematic review and meta-analysis

PURPOSE

To determine the effect of isolated medial patellofemoral ligament reconstruction (MPFLR) versus concomitant MPFLR and tibial-tubercle osteotomy (TTO) on patient-reported functional outcomes, rate of patellar redislocation, and rate of return to sport in skeletally mature patients with recurrent patellar instability and lateralization as defined by elevated tibial-tubercle trochlear groove (TT-TG) distance.

METHODS

Three databases MEDLINE, PubMed and EMBASE were searched from inception to July 10th, 2022 for literature outlining the management of patients with TT-TG indices greater than 15 mm with either isolated MPFLR or concomitant MPFLR and TTO procedures. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on functional outcomes via the Kujala anterior knee pain score, redislocation rates, return to sport rates, and complications were recorded. The MINORS score was used for all studies to perform a quality assessment of included studies.

RESULTS

A total of 31 studies comprising 1405 patients (1452 knees) were included in this review. The mean Kujala score in 13 studies comprising 848 total patients in the isolated MPFLR group was 85.0 (range 80.9-97.5) compared to a score of 83.7 (range 77.2-94.0) in 14 studies comprising 459 patients in the concomitant group. The mean pooled redislocation rate in 19 studies examining isolated MPFLR procedures comprising 948 patients was 3.1% (95% CI 2.1-4.4%, I² = 7%) as opposed to 3.2% (95% CI 1.9-5.0%, I² = 0%) in 15 studies comprising 486 patients in the concomitant group. The mean pooled return to sport rate in seven studies with 472 total patients in the isolated MPFLR group was 82% (95% CI 78-86%, I² = 16%) compared to a score of 92% (95% CI 78-99%, I² = 58%) in four studies comprising 54 patients in the concomitant group. There were similar complication rates between both treatment groups, including range of motion deficits, fractures, infections, and graft failures.

CONCLUSION

Isolated MPFLR leads to similar anterior knee pain, similar redislocation rates and lower return to sport rates than concomitant MPFLR and TTO procedures in patients with TT-TG distances greater than 15 mm. Information from this review can aid surgeons in their decision to choose MPFLR versus concomitant procedures for this patient population, and can also guide future studies on this topic.

LEVEL OF EVIDENCE

Level IV.

Quality of life following medial patellofemoral ligament reconstruction combined with medial tibial tubercle transfer in patients with recurrent patellar dislocation: a retrospective comparative study

Background

Because the patients undergoing medial patellofemoral ligament reconstruction (MPFLr) combined with medial tibial tubercle transfer (TTT) procedure are usually young and active, the quality of life (QoL) is also an important prognostic factor for patients with recurrent patellar dislocation. Assessing QoL can provide more useful and accurate evidence for the effects of this procedure. This study aimed to evaluate QoL following MPFLr combined with TTT, compared with isolated MPFLr (iMPFLr).

Methods

Fifty-one patients who underwent iMPFLr + TTT and 48 patients who underwent iMPFLr were included. Clinical evaluation included QoL (EQ-5D-5L and EQ-5D VAS), functional outcomes (Kujala, Lysholm and Tegner activity scores), physical examinations (patellar apprehension test and range of motion) and redislocation rates. Radiological evaluation included patellar tilt angle and bisect offset. These preoperative and postoperative results were compared between groups at baseline and the final follow-up. The paired and independent t tests were used for the data following a normal distribution. Otherwise, the Wilcoxon and Mann–Whitney U tests were used to analyze the differences. Categorical variables were compared by chi-square or Fisher’s exact test.

Results

All of the QoL (EQ-5D-5L and EQ-5D VAS), clinical results and radiological outcomes significantly improved in both groups at the final follow-up, with no significant differences between groups. There was no significant difference in five dimensions of EQ-5D at the final follow-up, although percentages of people with problems of mobility and pain/discomfort were higher in the MPFLr + TTT group. Female patients had lower EQ-5D index and EQ-5D VAS compared with male patients in both groups at the final follow-up, but there was only a significant difference in the EQ-5D VAS.

Conclusions

Both MPFLr + TTT and iMPFLr groups obtained similar and satisfactory improvements in the QoL, clinical results and radiological outcomes, indicating that MPFLr combined with TTT is a safe and effective procedure, which can significantly improve the QoL for patients with recurrent patellar dislocation in cases of pathologically lateralized TT. However, female patients obtained lower QoL than males.

Distalization of tibial tubercle osteotomy is not necessary for patients with recurrent patellar dislocation accompanied by patella alta and increased TT-TG distance

Background

The aim of this study is to determine whether distalization of the tibial tubercle is necessary for patients with recurrent patellar dislocation accompanied by patella alta and increased TT-TG.

Methods

In this retrospective study, all 70 patients (70 knees) with recurrent patellar dislocation accompanied by TT–TG distance ≥20 mm and patella alta (CD-I ≥ 1.4) were surgically treated using MPFLR combined with medialization of the tibial tubercle or medialization and distalization of the tibial tubercle in the Third Hospital of Hebei Medical University between 2017 and 2019. 33 patients(33 knees) received MPFLR combined with medialization of the tibial tubercle (MPFLR + TTm group), 37 patients(37 knees) received MPFLR combined with medialization and distalization of the tibial tubercle (MPFLR + TTm-d group). Evaluation indicators included knee injury and osteoarthritis prognostic score (KOOS) and Kujala score evaluation, congruence angle (CA), patellar tilt angle (PTA), TT-TG distance, Blackburne-Peel index (BP-I), Caton-Deschamps index (CD-I).

Results

A total of 70 knees (70 patients) with a mean follow-up time of 32 ± 6 months were evaluated in the present study. The postoperative, the PTA, CA, CD-I, BP-I, and TT-TG distance significantly improved in the two groups (P < 0.05), and there was no statistical difference between the two groups (>0.05). The KOOS and Kujala scores of the two groups at the last follow-up were significantly higher than the preoperative scores (P < 0.05), and there was no statistical difference between the two groups (P>0.05). No complications were noted in either group.

Conclusion

For patients with recurrent patellar dislocation accompanied by increased TT-TG distance and patella alta, distalization is not needed and medialization is sufficient even in the presence of patella alta.

[Change in the treatment of tibial plateau fractures]

BACKGROUND

The treatment of tibial plateau fractures has experienced a number of very different conceptual developments in recent years, not only with respect to technical innovations but also against the background of changing fracture patterns and the growing requirements of patients.

OBJECTIVE

What developments in recent years have had a significant impact on current treatment strategies for tibial plateau fractures?

METHODS

Narrative review of publications listed in PubMed on the topic of treatment of complex tibial plateau fractures.

RESULTS

While the two-dimensional classifications are becoming less important, computed tomography (CT)-based three-dimensional assessment of fracture progression and an access strategy based on it are coming to the fore. Direct dorsal approaches have been shown to be superior, particularly in the case of relevant posteromedial and/or posterolateral fracture involvement. The step-by-step approach extension via specific osteotomies of ligamentous attachments also enables a needs-dependent and fracture-dependent complete joint visualization and reduction control. In the treatment of geriatric tibial plateau fractures, primary treatment with endoprostheses is becoming increasingly more important to enable early mobilization under full load bearing with significantly shorter rehabilitation times.

CONCLUSION

Modern developments in the context of fracture treatment around the tibial plateau have led to a relevant reduction of infections and improved surgical outcomes; however, the high demands and the improved understanding of fractures still underline the great challenge in the treatment of complex fracture patterns.

[Patellofemoral cartilage repair]

Anterior knee pain is a frequent symptom in young athletes. Symptomatic patellofemoral cartilage defects can occur after trauma, especially after patellar dislocation. Numerous cartilage repair methods are currently available. Due to co-pathologies, the outcome after patellofemoral cartilage repair is inferior to the treatment of cartilage defects of the tibiofemoral joint. Adequate addressing of coexisting pathologies is essential for treatment success. This review provides an overview of the different techniques of patellofemoral cartilage repair.

Tibial Tubercle Osteotomy May Not Provide Additional Benefit in Treating Patellar Dislocation With Increased Tibial Tuberosity-Trochlear Groove Distance: A Systematic Review

PURPOSE

To examine the indications and outcomes of medial patellofemoral ligament reconstruction (MPFLR) with or without tibial tubercle osteotomy (TTO) in treating recurrent or habitual patellar dislocation with an increased tibial tuberosity-trochlear groove (TT-TG) distance.

METHODS

We performed a literature search of the established medical databases Cochrane Central, PubMed-MEDLINE, EMBASE, and Web of Science. The inclusion criteria were as follows: skeletally mature patients with recurrent or habitual patellar dislocation and an increased TT-TG distance, treatment with MPFLR combined with a TTO procedure or isolated MPFLR, and reporting of clinical outcomes and complications. Each study was assessed for quality and the level of evidence. The general characteristics, indications, surgical techniques, TT-TG distance, clinical results, imaging evaluation findings, and complications of each study were recorded.

RESULTS

Nine studies consisting of 288 knees met the inclusion criteria. The average Coleman score was 71.56 (range, 55-83). The threshold for an increased TT-TG distance ranged from 16 to 20 mm in the included studies. Similar good postoperative outcomes were reported in patients with an increased TT-TG distance treated with MPFLR with versus without a TTO procedure. The mean postoperative Lysholm score ranged from 75.0 to 94.7 (I² = 87.6%) in the isolated MPFLR group and from 85.0 to 87.6 (I² = 16.3%) in the TTO-with-MPFLR group. Similar postoperative congruence angles were reported in both groups. The postoperative redislocation rate ranged from 0% to 4.2% in the TTO-with-MPFLR group, and no redislocation was found in the isolated MPFLR group. The postoperative apprehension sign was only reported in isolated MPFLR patients.

CONCLUSIONS

The outcomes of MPFLR with or without TTO to treat recurrent or habitual patellar dislocation with an increased TT-TG distance appeared similar. However, this study was limited by the considerable heterogeneity, variety of techniques, variety of TT-TG distances, and variability in patella alta and trochlear dysplasia among the included studies.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II to IV studies.

Online Rehabilitation Protocols for Medial Patellofemoral Ligament Reconstruction With and Without Tibial Tubercle Osteotomy Are Variable Among Institutions

Purpose

To compare and contrast the various rehabilitation protocols for medial patellofemoral ligament (MPFL) reconstruction and MPFL reconstruction plus tibial tubercle osteotomy (TTO) published online by academic orthopaedic surgery residency programs and private practice institutions throughout the United States.

Methods

We performed a systematic electronic search of MPFL reconstruction rehabilitation protocols in academic orthopaedic surgery residency programs in the United States using Google’s search engine (www.google.com) based on the Fellowship and Residency Electronic Interactive Database Access System (FREIDA). Private practice organizations publishing MPFL reconstruction or MPFL reconstruction–TTO rehabilitation protocols that were found on the first page of search results were also included, but no comprehensive search for private practice protocols was performed. Protocols specifying an MPFL reconstruction with TTO were included for separate review because of altered weight-bearing status postoperatively. A list of comparative criteria was created to assess the protocols for the presence and timing of the various rehabilitation components.

Results

From the list of 189 U.S. academic residency programs, as well as additional private practice protocols found in the Google search, 38 protocols were included for review (31 protocols for isolated MPFL reconstruction and 7 protocols for MPFL reconstruction plus TTO). A return to full range of motion by week 6 was recommended by 15 (48.4%) of the isolated MPFL reconstruction protocols and 6 (85.7%) of the MPFL reconstruction–TTO protocols. Six weeks of knee brace wear was recommended by 13 isolated MPFL reconstruction protocols (43.3%) and 4 MPFL reconstruction–TTO protocols (57.1%). Moreover, 6 isolated MPFL reconstruction protocols (19.4%) and 3 MPFL reconstruction–TTO protocols (42.9%) recommended use of a patellar stabilizing brace postoperatively.

Conclusions

There is substantial variability among rehabilitation protocols after MPFL reconstruction, as well as MPFL reconstruction plus TTO, including postoperative range of motion, weight-bearing status, and time until return to sport. Furthermore, many online protocols from academic orthopaedic surgery residency programs and private practices in the United States fail to mention several of these parameters, most notably functional testing to allow patients to return to sport.

Clinical Relevance

Proper rehabilitation after MPFL reconstruction with or without TTO is an important factor to a patient’s postoperative outcome. This study outlines the variability in online rehabilitation protocols after MPFL reconstruction with or without TTO published online by academic residency programs and private practice institutions.

[Patellar dislocation : Causes and treatment]

The causes of patellofemoral instability (PFI) are complex. In accordance with the current literature a classification was developed which clearly weights all entities and derives diagnostic and therapeutic consequences. It considers patellar instability and patellar maltracking or the complete loss of patellar tracking and differentiates into 5 types. Type 1: patellar dislocation without maltracking or instability with a low risk of redislocation. Type 2: high risk of redislocation, no maltracking. Type 3: instability and maltracking; reasons for maltracking are a) soft tissue contracture, b) patella alta, c) pathological tibial tuberosity trochlear groove (TTTG) distance, c) valgus deformities and e) torsional deformities. Type 4: massively unstable floating patella, which is based on a high-grade trochlear dysplasia. Type 5: maltracking without instability.

Objective assessment of patellar maltracking with 3 T dynamic magnetic resonance imaging: feasibility of a robust and reliable measuring technique

Patellofemoral maltracking predisposes the patellofemoral joint to instability. The purpose of this study was to provide a reliable dynamic magnetic resonance imaging (MRI) measuring technique for patellofemoral maltracking, and to investigate the influence of anatomical risk factors (AF) on patellar maltracking. Ten patients (2 males,8 females, average 19 years) with clinical maltracking and 20 controls (10 males,10 females,average 28 years) were examined with a dynamic, multi-slice gradient-echo MRI sequence, during repetitive flexion(40°) and full extension, in an open-chain-active-movement. In a 30-s time frame three simultaneous transverse slices were acquired. Dynamic mediolateral translation and dynamic tilt were measured at defined positions, by two independent examiners. Reproducibility was tested in a set of five knees. Common AFs for patellar maltracking (tibial-tuberosity-to-trochlear-groove-(TT-TG)-distances, trochlea-sulcus-angle, trochlea-sulcus-depth, lateral-trochlear-inclination and Caton-Deschamps-Index) were analyzed in consensus, using standard static MRI sequences. In patients, dynamic mediolateral translation was significantly greater in patients (12.4 ± 6.9 mm vs. − 0.1 ± 2.3 mm, p < 0.001) and the patella was positioned significantly more laterally (17.5 ± 6.9 mm vs. 3.1 ± 2.4 mm, p < 0.001) compared to controls. During movement, the patella tilted 16.3 ± 13.1° laterally in patients and 1.9 ± 4.3° medially in controls (dynamic tilt) (p < 0.002). All AFs were significantly different between patients and controls. Pathological TT-TG-distances, Caton-Deschamps-Indices and trochlea-sulcus-angles strongly correlated with dynamic patellar translation and dynamic patellar tilt (p < 0.001). In the patient population, the primary pathologies for maltracking were lateralized-tibial-tubercle (n = 5), trochlea dysplasia n = 2, patella alta (n = 3). Interrater-reliability for translation and tilt-measurement was excellent (0.971/0.976, 95% CIs 0.939–0.986/0.950–0.988). Dynamic MRI reliably differentiates between abnormal and physiological patellar tracking. Dynamic tracking and tilt strongly correlate with measurable AFs, which reinforces their clinical use and validates the presented technique.

Conservative Versus Surgical Treatment for Primary Patellar Dislocation

BACKGROUND

Primary patellar dislocation is often the initial manifestation of patellofemoral instability. Its long-term consequences can include recurrent dislocation and permanent dysfunction of the knee joint. There is no consensus on the optimal treatment of primary patellar dislocation in the relevant literature. The main prerequisite for a good long-term result is a realistic assessment of the risk of recurrent dislocation.

METHODS

We carried out a systematic literature search in OvidSP (a search engine for full-text databases) and MEDLINE to identify suitable stratification models with respect to the risk of recurrent dislocation.

RESULTS

In the ten studies included in the current analysis, eight risk factors for recurrence after primary patellar dislocation were identified. Six studies revealed a higher risk in younger patients, particularly those under 16 years of age. The sex of the patient had no clear influence. In two studies, bilateral instability was identified as a risk factor. Two anatomical risk factors-a high-riding patella (patella alta) and trochlear dysplasia-were found to have the greatest influence in six studies. In a metaanalysis of five studies, patella alta predisposed to recurrent dislocation with an odds ratio (OR) of 4.259 (95% confidence interval [1.9; 9.188]). Moreover, a pathologically increased tibial tuberosity to trochlear groove (TT-TG) distance and rupture of the medial patellofemoral ligament (MPFL) on the femoral side were associated with higher recurrence rates. Patients with multiple risk factors in combination had a very high risk of recurrence.

CONCLUSION

The risk of recurrent dislocation after primary patellar dislocation is increased by a number of risk factors, and even more so when multiple such risk factors are present. Published stratification models enable an assessment of the individual risk profile. Patients at low risk can be managed conservatively; surgery should be considered for patients at high risk.

Closed-wedge Patelloplasty for the Treatment of Distal Patellofemoral Maltracking and Instability due to Severe Patellar Dysplasia: Case Report and Surgical Technique

Background

Patellofemoral maltracking is caused by different anatomical factors. Most of them are associated with a proximal maltracking, which alters the patella's engagement into the trochlear groove and predisposes the patellofemoral joint for instability. Different surgical techniques have been described to realign patellar tracking, however, most of which address proximal patellar maltracking.

Aim

The aim of this article is to demonstrate the influence of patella-related deformities on patellar tracking and to present a novel surgical technique for the treatment of distal patellar maltracking, caused by a severe patellar dyplasia.

Case Description

We report the case of a 23-year-old patient with a severe patellar dysplasia, presenting a distal patellar maltracking with recurring dislocations in deep flexion. Due to her instability, the patient was immobilised and dependent on the constant use of walking aids. Radiological images showed a concavely shaped patellar, which articulated exclusively with the lateral epicondyle and caused the patella to dislocate laterally, starting at a flexion angle of 60°. An anterior closing-wedge osteotomy was used to reshape and recenter the patella, which was complemented by a medial patellofemoral ligament reconstruction. At the 18-month follow-up, the patient presented pain free and fully remobilised, without the use of walking aids. Patellar tracking was reestablished, with a possible knee flexion until 140°. No redislocation of the patella had occurred.

Conclusion

Distal patellofemoral maltracking, caused by a severe patellar dysplasia, can successfully be treated with an anterior closed-wedge osteotomy of the patella. In combination with a medial patellofemoral ligament reconstruction, patellofemoral stability can be reestablished, to prevent further dislocations.

Clinical Significance

There are multiple factors, which may cause patellar maltracking. A thorough clinical and radiological preoperative analysis is mandatory, in order to clearly identify the underlying pathologies, as these may affect patellar tracking proximally or distally.

How to cite this article

Frings J, Freudenthaler F, Krause M, et al. Closed-wedge Patelloplasty for the Treatment of Distal Patellofemoral Maltracking and Instability due to Severe Patellar Dysplasia: Case Report and Surgical Technique. Strategies Trauma Limb Reconstr 2020;15(3):184-192.