I.S.Mu.L.T. first-time patellar dislocation guidelines

Outcomes of surgical treatment of patellar instability in children with Down syndrome

BACKGROUND

patellar instability is a relatively frequent musculoskeletal disorder in children with Down syndrome (DS). However, such a condition has seldom been studied in the literature, even less its surgical treatment. Different techniques have been offered for this condition; the evidence for surgical options is scarce and primarily based on case reports or case series with few patients and heterogeneous techniques. Given this background, we aimed to evaluate the outcomes of a uniform kind of surgical procedure for such a condition that combined lateral soft tissue release, medial patellofemoral ligament (MPFL) reconstruction (using a partial-thickness quadriceps tendon autograft), the Roux-Goldthwait procedure, and V-Y quadricepsplasty (if needed).

MATERIALS AND METHODS

This retrospective study involved 11 skeletally immature patients (12 knees; 9 males and 2 females), 5.5 to 14.1 years of age, with DS who had patellofemoral instability (PFI) and were managed by this technique between October 2018 and March 2020. Preoperative radiography, CT scan, and MRI were performed to evaluate the physis status, lower limb alignment, patellar height, trochlear morphology, and any associated knee pathology. A functional knee assessment was done by using the Kujala score and the modified Lysholm score.

RESULTS

The mean time of follow-up (± SD) was 47.7 ± 5.8 months (range: 39-56). Pre-operatively, the Kujala score (± SD) was 52.6 ± 14.3 (range: (31-74), and at final follow-up, it was 92.2 ± 4.4 (range: (88-98), showing a significant improvement (P < 0.001). The preoperative modified Lysholm score (± SD) was 54.3 ± 8.1 (range: 39-62), and at final follow-up it was 92.4 ± 5.3 (range: 82-96), showing a significant improvement (P < 0.001). All patients had a stable patella without a recurrence of instability and regained full ROM. There was no incidence of a patellar fracture or femoral physis injury.

CONCLUSIONS

Our proposed technique of combined soft tissue procedures, including lateral soft tissue release, MPFL reconstruction (using a partial-thickness quadriceps tendon autograft), the Roux-Goldthwait procedure, and V-Y quadricepsplasty, was an effective method for treating patellar instability in children with DS while avoiding physeal injury and patellar fracture. Functional scores and radiological outcomes were improved.

LEVEL OF EVIDENCE

IV; retrospective case series.

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.

Medial patellar ligament reconstruction in combination with derotational distal femoral osteotomy for treating recurrent patellar dislocation in the presence of increased femoral anteversion: a systematic review

BACKGROUND

Medial patellar ligament reconstruction (MPFL-R) in combination with derotational distal femoral osteotomy (DDFO) for treating recurrent patellar dislocation (RPD) in the presence of increased femoral anteversion is one of the most commonly used surgical techniques in the current clinical practice. However, there are limited studies on the clinical outcomes of MPFL-R in combination with DDFO to treat RPD in the presence of increased femoral anteversion.

PURPOSE

To study the role of MPFL-R in combination with DDFO in the treatment of RPD in the presence of increased femoral anteversion.

METHODS

A systematic review was performed according to the PRISMA guidelines by searching the Medline, Embase, Web of Science, and Cochrane Library databases through June 1, 2023. Studies of patients who received MPFL-R in combination with DDFO after presenting with RPD and increased femoral anteversion were included. Methodological quality was assessed using the MINORS (Methodological Index for Nonrandomized Studies) score. Each study's basic characteristics, including characteristic information, radiological parameters, surgical techniques, patient-reported outcomes, and complications, were recorded and analyzed.

RESULTS

A total of 6 studies with 231 patients (236 knees) were included. Sample sizes ranged from 12 to 162 patients, and the majority of the patients were female (range, 67-100%). The mean age and follow-up ranges were 18 to 24 years and 16 to 49 months, respectively. The mean femoral anteversion decreased significantly from 34° preoperatively to 12° postoperatively. In studies reporting preoperative and postoperative outcomes, significant improvements were found in the Lysholm score, Kujala score, International Knee Documentation Committee score, and visual analog scale for pain. Postoperative complications were reported in all studies, with an overall reported complication rate of 4.7%, but no redislocations occurred during the follow-up period.

CONCLUSION

For RPD with increased femoral anteversion, MPFL-R in combination with DDFO leads to a good clinical outcome and a low redislocation rate. However, there was no consensus among researchers on the indications for MPFL-R combined with DDFO in the treatment of RPD.

The Importance of Medial Patellar Shape as a Risk Factor for Recurrent Patellar Dislocation in Adults

BACKGROUND

Research on the cause of lateral patellar dislocation (LPD) has focused on trochlear morphologic parameters, joint alignment, and patellofemoral soft tissue forces. A paucity of information is available regarding how patellar morphologic parameters influence the risk for LPD.

PURPOSE/HYPOTHESIS

The purpose was to assess whether patellar morphology is a risk factor for recurrent LPD. It was hypothesized that (1) patients with recurrent LPD would have decreased patellar width and volume and (2) patellar morphologic parameters would accurately discriminate patients with recurrent LPD from controls.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

A total of 21 adults with recurrent LPD (age, 29.7 ± 11.1 years; height, 170.8 ± 9.9 cm; weight, 76.1 ± 17.5 kg; 57% female) were compared with 21 sex- and height-matched controls (age, 27.2 ± 6.7 years; height, 172.0 ± 10.6 cm; weight, 71.1 ± 12.8 kg; 57% female). Three-dimensional axial fat-saturated magnetic resonance imaging scans were used to measure patellar medial, lateral, and total width; patellar volume; patellar medial and lateral facet length; the Wiberg index; and previously validated knee joint alignment and femoral shape measurements (eg, tibial tuberosity to trochlear groove distance, trochlear dysplasia).

RESULTS

The LPD group demonstrated reduced medial patellar width (Δ = -3.6 mm; P < .001) and medial facet length (Δ = -3.7 mm; P < .001) but no change in lateral width or facet length. This resulted in decreased total patellar width (Δ = -3.2 mm; P = .009), decreased patellar volume (Δ = -0.3 cm3; P = .025), and an increased Wiberg index (Δ = 0.05; P < .001). No significant differences were found for all other patellar shape measures between cohorts. Medial patellar width was the strongest single discriminator (83.3% accuracy) for recurrent LPD. Combining medial patellar width, patellofemoral tilt, and trochlear groove length increased the discrimination to 92.9%.

CONCLUSION

The medial patellar width was significantly smaller in patients with recurrent LPD and was the single most accurate discriminator for recurrent LPD, even compared with traditional trochlear shape and joint alignment measures (eg, trochlear dysplasia, patella alta). Therefore, medial patellar morphology should be assessed in patients with LPD as a risk factor for recurrence and a potential means to improve treatment.

Factors associated with an increased risk of osteochondral injuries after patellar dislocations: a systematic review

PURPOSE

The purpose of the study was to summarize the available evidence and identify risk factors for osteochondral injuries (OCIs) after patellar dislocations.

METHODS

A systematic literature review was conducted in PubMed, Embase, Web of Science, Cochrane Library, and China national knowledge infrastructure from inception to December 22, 2022, according to the preferred reporting items for systematic reviews and meta-analyses guidelines. Studies regarding risk factors for OCIs after patellar dislocations were included. Literature search, data extraction, and quality assessment were performed independently by two authors.

RESULTS

A total of 16 studies with 1945 patients were included. The risk factors for OCIs after patellar dislocation were categorized into four main categories, including demographic characteristics, patellar depth and position, femoral trochlear morphology, and other risk factors in this study. Five and three studies supported the idea that male sex and skeletal maturation may be risk factors, respectively. Normal femoral trochlea (two studies) and complete medial patellofemoral ligament (MPFL) injuries (two studies) may be associated with the development of OCIs. Three studies show that ligamentous laxity or joint hypermobility may prevent OCIs. Patellar depth and position (eight studies) may not be associated with the development of OCIs.

CONCLUSIONS

Based on the available evidence, an increased risk of OCIs following patellar dislocation may be associated with male sex and skeletal maturation. Furthermore, normal femoral trochlea and complete MPFL injuries may increase the risk of OCIs, while factors such as ligamentous laxity or joint hypermobility may reduce the risk.

LEVEL OF EVIDENCE

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

Isolated medial patellofemoral ligament reconstruction improves static bipedal balance control in young patients with recurrent lateral patellar instability

BACKGROUND

Knee stability can be safely and reliably restored using medial patellofemoral ligament (MPFL) reconstruction, which is widely recognized in patients with recurrent lateral patellar instability. However, the literature regarding its influence on static balance control is limited. Thus, this study aimed to assess the impact of MPFL reconstruction on balance control and determine its functional significance.

METHODS

The study comprised 26 patients with recurrent lateral patellar instability, scheduled for MPFL reconstruction, and 26 matched healthy controls who underwent double-leg stance static posturographic tests pre- and postoperatively on a vertical force platform. Four test conditions were performed with their eyes open and closed, without and with foam support to evaluate the balance control of all participants. The International Knee Documentation Committee subjective knee form, Lysholm knee scoring scale, Tampa scale for kinesiophobia, and active range of motion of the affected knee were synchronously obtained and assessed.

RESULTS

More postural sway was observed in patients compared to the healthy controls, 11 ± 5 days preoperatively (p < 0.01). However, 374 ± 23 days postoperatively, postural sway between the patients and control subjects was comparable (p > 0.05). Patients following MPFL reconstruction demonstrated better postural stability (p < 0.01). Significant ameliorations were found in all clinical assessments in the study patients postoperatively (p < 0.01).

CONCLUSIONS

Patients with recurrent lateral patellar instability have inefficient balance control. Static bipedal balance control can be improved under surface perturbation in these patients one year after isolated MPFL reconstruction that enhances the possibility of normal restoration of postural stability. Structural recovery of the ligament could help restore the sensorimotor efficiency and generate the compensatory and anticipatory balance regulation strategies, thereby improving joint function.

Medial patellofemoral ligament reconstruction appears to be a better treatment than repair, proximal realignment, or conservative management for primary patellar dislocation: A network meta-analysis

BACKGROUND

The purpose of this study was to compare the functional outcomes and re-dislocation rates of medial patellofemoral ligament (MPFL) reconstruction, MPFL repair, combined proximal realignment (CPR), and conservative management for primary patellar dislocation by conducting a systematic literature search of the available studies. The hypothesis was that MPFL repair and MPFL reconstruction would be better options for treating primary patellar dislocation.

METHODS

Randomized controlled trials or prospective studies of primary patellar dislocation treated with MPFL reconstruction, MPFL repair, CPR, or conservative management were identified from the MEDLINE, EMBASE, and the Cochrane Library databases through December 31, 2021. A total of 626 patients met the prespecified inclusion criteria. The methodological quality of each study was assessed using a risk of bias table, Detsky quality index, and Newcastle-Ottawa Scale. The end-point data collected included comparisons of the mean in functional scores on knee outcomes scales and the number of patients who experienced re-dislocation. A network meta-analysis of the relevant literature was performed to investigate which treatment showed better outcomes.

RESULTS

In total, 10 trials were included in this study. There was no statistically significant difference in the subgroup analysis in terms of the functional outcomes among MPFL reconstruction, MPFL repair, CPR, and conservative management. However, MPFL reconstruction showed statistically significantly better outcomes than MPFL repair, CPR, or conservative management in terms of the re-dislocation rate. Additionally, surface under the cumulative ranking curve percentage showed that MPFL reconstruction had a lower probability of re-dislocation than MPFL repair even though there was no significant difference (0.24, 95% confidence interval: 0.02-2.91).

CONCLUSION

Using a network meta-analysis, this meta-analysis showed that there was no significant difference in functional outcomes in a subgroup analysis. In re-dislocation subgroup analysis, MPFL repair and MPFL reconstruction produced significantly better results than other treatments. Also, surface under the cumulative ranking curve percentage showed that MPFL reconstruction had a lower probability of re-dislocation than MPFL repair.

Tibial Tubercle-Trochlear Groove Distance Has Better Diagnostic Reliability Than Tubercle-Posterior Cruciate Ligament Distance For Predicting Patellar Instability: A Systematic Review

OBJECTIVE

The tibial tubercle-trochlear groove (TT-TG) distance is now routinely utilized to help determine whether a realignment procedure is necessary for patients with patellar instability. The tibial tubercle-posterior cruciate ligament (TT-PCL) distance has been explored as an alternative measurement. The aim of this study is to compare the reliability of TT-TG and TT-PCL; to explore whether there is a relationship between the TT-PCL and the TT-TG distance; to determine whether there is a relationship between the TT-TG and TT-PCL distances and knee rotation; and to compare the abilities of the TT-PCL distance and the TT-TG distance with predicted patellar instability.

METHOD

This systematic review was performed in accordance with PRISMA guidelines. Three databases, PubMed, EMBASE, and Cochrane Central Register of Controlled Trials, were searched from inception to September 2021 to identify clinical studies comparing TT-TG and TT-PCL distances to patellar instability. Data on patient baseline characteristics, TT-TG and TT-PCL distances, inter-observer reliability, and area under the receiver-operating characteristic curve (AUC) were recorded. The methodological quality of the studies was assessed using the quality assessment form recommended by the Agency for Healthcare Research and Quality (AHRQ).

RESULT

Twenty studies were included in the final analysis, comprising 2330 knees from 2260 patients. The current study showed that TT-TG and TT-PCL have similar observer reliability. The inter- and intra-observer reliability of TT-TG ranged from 0.807 to 0.98 and 0.553 to 0.99, respectively. The inter- and intra-observer reliability of TT-PCL ranged from 0.553 to 0.99 and 0.88 to 0.981, respectively. Six studies compared the AUC for predicting patellar instability and showed that TT-TG had better predictive performance than TT-PCL. Three studies reported a correlation between TT-TG and knee rotation, but no such relationship was found for TT-PCL. Eight studies reported a weak or moderate correlation between TT-TG and TT-PCL.

CONCLUSION

TT-TG and TT-PCL have similar inter- and intra-rater reliability (as measured by ICC), but TT-TG has greater discriminatory power to predict patellar instability than TT-PCL (as measured by AUC values and odds ratio). However, considering trochlear dysplasia and individual variations, future studies need to find more accurate and individualized methods to predict patellar instability.

Suprapatellar pouch effusion is associated with an increased risk of neglected osteochondral fractures in primary acute traumatic patellar dislocation: a consecutive series of 113 children

BACKGROUND

The aim of this study was to investigate the risk factors of neglected osteochondral fractures in primary acute traumatic patellar dislocation in the pediatric population.

METHODS

A total of 113 patients with primary acute traumatic patellar dislocation for whom coincident osteochondral fractures could not be confirmed by X-ray examination at initial diagnosis between January 2010 and February 2022 were retrospectively analyzed. Medical history, physical examination, and radiographic images were recorded in detail. The greatest dimension of the suprapatellar pouch (SP) effusion on radiograph was measured. Computed tomography and magnetic resonance imaging were used to confirm the presence of neglected osteochondral fractures and measure the fragment size. Potential risk factors were calculated and correlated with reference to the neglected osteochondral fractures and fragment size using multivariate linear regression analysis.

RESULTS

Weight, walking ability, effusion grade, and SP measurement had a significant correlation with neglected osteochondral fractures in primary acute traumatic patellar dislocation (p = 0.046; p < 0.001; p = 0.048; p < 0.001). The cutoff point was 53.5 kg for weight and 18.45 mm for SP measurement. In the neglected fractures group, SP measurement was statistically significant with larger fragment size (beta value = 0.457; p < 0.001), and the cutoff point was 26.2 mm.

CONCLUSIONS

SP effusion is not only associated with an increased risk of neglected osteochondral fractures in primary acute traumatic patellar dislocation but also with larger fragment size. Knee radiograph, medical history, and physical examination can predict the need for further imaging examination and even surgery in primary acute traumatic patellar dislocation.

Patellar instability-induced bone loss in the femoral trochlea is associated with the activation of the JAK1/STAT3 signaling pathway in growing mice

INTRODUCTION

Patellar instability (PI) at an early age is believed closely correlated with bone loss in the development of the femoral trochlea and can cause trochlear dysplasia. However, the molecular mechanism of PI-induced bone loss has not been established. The Janus kinase (JAK)/signal transducers and activators of transcription (STAT) signaling pathway plays an important role in bone development by regulating the expression of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL). The aim of this study was to explore the association of JAK1/STAT3 signaling to PI-induced subchondral bone loss in the femoral trochlea.

METHODS

Four-week-old male C57BL/6 mice were randomly divided into two groups (n = 50/group). Mice in the experimental group underwent surgery to induce PI. Distal femurs were collected 2 and 4 weeks after surgery (n = 25 knees/each time point, each group). Microcomputed tomography and histological observations were performed to investigate the morphology of the femoral trochlea and changes in bone mass. qPCR, western blot, and immunohistochemistry analyses were performed to evaluate the expression of JAK1, STAT3, RANKL, and OPG in subchondral bone. A t test was performed for the statistical analysis; a P value < 0.05 was considered to be statistically significant.

RESULTS

In the experimental group, subchondral bone loss in the femoral trochlea was observed two and four weeks after PI; morphological changes, such as a flatter trochlear groove and an increased sulcus angle, were observed in the femoral trochlea; qPCR, western blot, and immunohistochemistry analyses showed higher expression of JAK1, STAT3, and RANKL and lower expression of OPG (P < 0.05).

CONCLUSION

PI-induced subchondral bone loss in the femoral trochlea and resulted in trochlear dysplasia in growing mice. This bone loss is associated with activation of the JAK1/STAT3 signaling pathway, which weakens the function of osteoblasts and stimulates both formation and function of osteoclasts.

Allografts for Medial Patellofemoral Ligament (MPFL) Reconstruction in Adolescent Patients with Recurrent Patellofemoral Instability: A Systematic Review

This systematic review updates the currently available evidence on medial patella-femoral ligament (MPFL) reconstruction using allografts. The outcomes were measured with patient-reported outcome measures (PROMs), redislocation and complication rates. This study was performed according to the 2020 PRISMA guidelines using the PubMed, Scopus, Web of Science databases, accessed in February 2023. Studies examining the clinical outcomes of MPFL reconstruction with allografts in adolescents and children with recurrent patellofemoral instability (PFI) were included. Data from three trials, including 113 surgical procedures in 121 children, were retrieved. 40% (48/121) of the included patients were girls. The mean age of the patients was 14.7 ± 0.8 years, and the mean follow-up length was 38.1 ± 16.5 months. With MPFL allograft reconstruction, the Kujala score improved by 14.7% (p < 0.0001) and the IKDC by 38.8% (p < 0.0001). The rate of dislocations was 5% (6 of 121), reoperation for instability was 11% (13 of 121), and subluxation was 2% (1 of 47). Conclusion: These results encourage the use of allografts for MPFL reconstruction in adolescent patients with recurrent patellofemoral instability. Though patellofemoral instability is common in clinical practice, the current literature lacks clinical evidence on allograft MPFL reconstruction. Additional high-quality investigations are required to properly establish the long-term advantages of allograft MPFL and its complication rate.

Increased lower limb length ratio in patients with patellar instability

PURPOSE

Patellar height is a risk factor for patellar instability, correlated with the tibia length/femur length (T/F) ratio. This study aimed to explore the changes in the T/F ratio in patients with patella instability and the potential correlation with the morphology of the patellofemoral joint and extensor moment arm.

METHOD

A retrospective analysis was performed to assess the ratio of lower limb length morphological characteristics of the patellofemoral by full weight-bearing long-leg standing radiographs, magnetic resonance imaging, and computed tomography in 75 patients with patellar instability and 75 participants from a randomly selected control group from January 2020 to September 2021. A total of eight parts were measured, including mechanical tibia length/femur length (mT/F) ratio, anatomical tibia length/femur length (aT/F) ratio, hip-knee-ankle angle, femoral neck-shaft angle, femoral valgus cut angle, patellar height, Dejour classification, sulcus angle, trochlear angle, medial trochlear inclination, lateral trochlear inclination, patella tilt angle and patellar tendon moment arm to evaluate the difference of morphology between patient group and control groups.

RESULTS

The mT/F (0.840 ± 0.031 vs. 0.812 ± 0.026, p < 0.001) and aT/F (0.841 ± 0.033 vs. 0.808 ± 0.028, p < 0.001) ratios in the patient group were significantly greater than that in the control group. There was a significant correlation between patellar height and increased mT/F and aT/F ratios (p < 0.05).

CONCLUSION

Patients with patellar instability had a larger lower limb length ratio, and the change in lower limb length ratio was correlated with patellar height.

LEVEL OF EVIDENCE IV

Current concepts in the treatment of first-time patella dislocation in children and adolescents

Background

Lateral dislocation of the patella is a common injury in children. It can occur in previously healthy and anatomically normal knees, but there are several abnormalities that predispose to patellar instability. Magnetic resonance imaging is an essential part of assessing for associated injuries and risk of further instability. Treatment aims to prevent redislocation, residual instability, osteoarthritis, and allow return to previous activities. The purpose of this review was to assess evidence for management of first-time patella dislocation in children and adolescents.

Methods

Literature review was performed, accompanied by the current best practice by the authors.

Results

Non-operative treatment is preferred, except where there are associated injuries such as osteochondral fractures that would benefit from surgery. The exact method of ideal non-operative management is not clearly defined but should focus on restoration of range of movement and strength with bracing as indicated. There seems to be a trend toward operative intervention that may well be inappropriate.

Conclusion

Further prospective studies are required with focus on the younger patient to fully understand if there is an at-risk group that would benefit from early surgery.

Level of evidence

level III.

Abnormal patellar loading may lead to femoral trochlear dysplasia: an experimental study of patellar hypermobility and patellar dislocation in growing rats

BACKGROUND

This animal study aimed to explore the effects of patellar hypermobility and patellar dislocation on the developing femoral trochlea.

METHODS

Seventy-two 3-week-old Wistar rats were randomly divided into three groups. The sham group (SG) underwent simple incision and suture of the skin and subcutaneous tissue; the patellar hypermobility group (PHG) underwent medial and lateral retinacular release and pie-crusting technique for the patellar ligament; the patellar dislocation group (PDG) underwent plication of the medial patellofemoral retinaculum. Twelve rats in each group were euthanized at 3 and 6 weeks postoperatively, respectively, and specimens were collected. The bony sulcus angle (BSA), cartilaginous sulcus angle (CSA), trochlear sulcus depth (TSD), and thickness of the cartilage on the lateral facet (CTL), medial facet (CTM), and center (CTC) of the trochlea were measured on hematoxylin and eosin-stained sections.

RESULTS

In the PHG and PDG, the femoral condyles became blunt, the trochlear groove became shallower, and cartilage became thicker compared with the SG. Compared with the SG, the PHG and PDG had significantly larger BSA and CSA values at 3 (p < 0.05) and 6 weeks (p < 0.005), and a significantly shallower TSD (p < 0.05). At 3 weeks, all cartilage thicknesses in the PHG and the CTC and CTM in the PDG were significantly thinner than in the SG (PHG vs. SG: p = 0.009 for CTL, p < 0.001 for CTM, p = 0.003 for CTC; PDG vs. SG: p = 0.028 for CTC, p = 0.048 for CTM). At 6 weeks, the CTC was thicker in the PHG and PDG than the SG (PHG vs. SG: p = 0.044; PDG vs. SG: p = 0.027), and the CTL was thinner in the PDG than the SG (p = 0.044).

CONCLUSION

Patellar hypermobility and patellar dislocation may result in trochlear dysplasia that worsens with age. Excessive or insufficient loading leads to trochlear dysplasia.

Surgical strategies for chondral defects of the patellofemoral joint: a systematic review

BACKGROUND

The management of chondral defects of the patellofemoral joint is debated, and definitive evidence is lacking. This study systematically updated and summarised the current literature on the surgical management of isolated chondral defects of the patellofemoral joint, discussing techniques, outcome, pitfalls, and new frontiers.

METHODS

This systematic review was conducted according to the 2020 PRISMA statement. In August 2022, PubMed, Web of Science, Google Scholar, and Embase databases were accessed with no time constrain. All the clinical studies investigating the surgical management of chondral defects of the patellofemoral joint were retrieved. Articles which reported data on patients with advanced to severe osteoarthritis were not eligible. Only studies with a minimum 24 months follow-up were considered. Studies which mixed results of patellofemoral and tibiofemoral joints were not considered.

RESULTS

Data from 10 studies (692 procedures) were retrieved. The mean follow-up was 46.9 ± 18.2 months. The mean age of the patients was 34.0 ± 6.1 years, and the mean BMI was 25.9 ± 0.8 kg/m². The mean duration of symptoms before the index surgery was 81.0 ± 24.0 months. The mean defect size was 3.8 ± 0.8 cm². All the PROMs improved from baseline to last follow-up: VAS 0-10 (P = 0.04), Tegner (P = 0.02), Lysholm (P = 0.03), and International Knee Documentation Committee (P = 0.03). The rate of hypertrophy was 5.6% (14 of 251), the rate of progression to total knee arthroplasty was 2.4% (2 of 83), the rate of revision was 16.9% (29 of 136), and the rate of failure was 13.0% (16 of 123).

CONCLUSION

Current surgical strategies may be effective to improve symptoms deriving from chondral defects of the patellofemoral joint. The limited and heterogeneous data included for analysis impact negatively the results of the present study. Further clinical studies are strongly required to define surgical indications and outcomes, and the most suitable technique.

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.

Synthetic graft for medial patellofemoral ligament reconstruction: a systematic review

Background

This systematic review investigates the role of synthetic graft for primary medial patellofemoral ligament (MPFL) reconstruction in patients with recurrent patellofemoral instability, focusing on clinical scores and the rate of complications.

Methods

This systematic review was conducted according to the PRISMA statement. The main online databases were accessed in January 2022 without time constraints. All clinical studies investigating the use of synthetic grafts for MPFL reconstruction were accessed. Revision settings were not considered. Only articles reporting data on patients with recurrent patellofemoral instability were eligible. Studies regarding congenital or acute patellofemoral dislocation were excluded. Only studies performing a follow-up longer than 24 months were considered.

Results

Data on 199 patients [mean age 22.3 (range 19.0–28.0) years] were collected. The mean follow-up was 60.5 (39.0–142.8) months. All the scores of interest improved at last follow-up: Kujala (+ 24.8; P = 0.0002), Lysholm (+ 42.0; P = 0.02), Tegner (+ 1.2; P = 0.03), IKDC (+ 20.9; P = 0.02). Post-operatively, a positive apprehension test was detected in 6.1% (7/115) of patients, and a sensation of instability was reported by 1.5% (3/199) of patients. The rate of re-dislocations was 2.5% (5 of 199 patients), and revision procedures were performed in less than 1% (1 of 199) of patients.

Conclusion

Synthetic graft may be reliable and feasible for primary MPFL reconstruction in patients with recurrent patellofemoral instability.

A new factor predicting excessive femoral anteversion in patients with recurrent patellar dislocation

PURPOSE

Determining a new imaging method on full-leg standing lower limb radiographs to predict excessive femoral anteversion in patients with patellar dislocation.

METHODS

This study included 119 patients with patellar dislocation from January 2014 to January 2021. The femoral anteversion and tibial torsion were measured by CT scanning. The medial condylar angle was measured by the full-leg standing lower limb radiographs. Pearson correlation coefficient was used to evaluate the correlation between rotation parameters and medial condylar angle.

RESULTS

Included patients were divided into DFO group and control group according to whether they received derotational femoral osteotomy (DFO) operation or not. DFO group had significantly higher femoral anteversion (29.8° ± 7.2° vs 23.1° ± 6.5°, P < 0.05), higher tibial torsion (28.6° ± 6.9° vs 24.7° ± 7.9°, P < 0.05), lower medial condylar angle (154.8° ± 4.7° vs 157.5° ± 6.7°, P < 0.05) than control group. Correlation analysis showed that the values of femoral anteversion were significantly correlated with medial condylar angle (r = -0.719, P < 0.001).

CONCLUSION

This study showed that medial condylar angle had a negative correlation with excessive femoral anteversion on the full-leg standing lower limb radiographs. The medial condylar angle can be a good predictor of femoral anteversion and can be used to guide the performance of DFO to treat patellar dislocation in clinical practice.

Dynamic versus static medial patellofemoral ligament reconstruction technique in the treatment of recurrent patellar dislocation: a randomized clinical trial protocol

BACKGROUND

The redislocation rate of conservatively treated patella instability is high. One of the leading surgical strategies is medial patellofemoral ligament reconstruction. Over-tensioning is one of the most challenging complications in static medial patellofemoral ligament reconstruction as the graft used for reconstruction is isometric and the anatomical MPFL is a mostly dynamic structure. As an alternative to established static reconstruction techniques, dynamic graft techniques have been introduced for stabilizing the patella with the aim of providing a more physiological reconstruction of the medial patellofemoral ligament. To date, data on clinical outcomes are scarce and on biomechanical outcomes of the dynamic MPFL reconstruction are lacking. Here, we present the protocol of a randomized clinical trial for comparing clinical and biomechanical outcomes of dynamic versus static medial patellofemoral ligament reconstruction.

METHODS

This study is a prospective, single blinded, randomized, multicenter, multimodal (clinical and biomechanical) clinical trial. Patients with recurrent patella dislocation requiring isolated MPFL reconstruction will be recruited and randomized to the dynamic or static reconstruction technique. Participants will be followed up for 2 years with a total of five follow-ups. Preoperative magnetic resonance imaging, upright radiographs, surgical reports and patient records will be evaluated, and clinical and functional outcomes will be measured. Patient-reported knee function and anterior knee pain as assessed with the Kujala score will serve as primary outcome. For biomechanical outcome, pre- and postoperative evaluations will be performed to assess isokinetic muscle strength, gait asymmetry, joint kinematics and kinetics, and timing of muscle activity.

DISCUSSION

The results of the study will clarify whether the reported surgery success for patella stabilization via dynamic MPFL reconstruction is due to muscle contraction or to the passive tenodesis effect combined with clinical outcome measures. With this study, we will provide much needed information on knee biomechanics after dynamic versus static MPFL reconstruction to provide evidence to support orthopedic surgeons in evidence-based decision-making in their quest for surgical techniques most favorable for their patients. Trial registration The study protocol was registered at clinicaltrials.gov (NCT04849130). Registered 19 April 2021, https://clinicaltrials.gov/ct2/show/NCT04849130 .

Hardware-free MPFL reconstruction in patients with recurrent patellofemoral instability is safe and effective

PURPOSE

This systematic review evaluated the clinical outcomes of hardware-free MPFL reconstruction techniques in patients with recurrent patellofemoral instability, focusing on patient-reported outcome measures (PROMs), redislocation rate, and complications. The hypothesis was that hardware-free MPFL reconstruction in patients with recurrent patellofemoral instability is safe and effective.

METHODS

This systematic review was conducted following the PRISMA guidelines. PubMed, Scopus, and Virtual Health Library databases were accessed in October 2021. All the clinical studies investigating the efficacy and feasibility of hardware-free MPFL reconstruction were screened for inclusion. Only studies with a minimum 24-month follow-up were considered eligible. Kujala Anterior Knee Pain Scale improvement and redislocation rate after surgical treatment were evaluated as primary outcomes. The rate of postoperative complications was evaluated as a secondary outcome. The quality of the methodological assessment was assessed using the Modified Coleman Methodology Score.

RESULTS

Eight studies were included in the present systematic review. The quality of the methodological assessment was moderate. Short- to long-term improvement of Kujala score was observed in all included studies. Mean score improvement ranged from + 13.2/100 to + 54/100, with mean postoperative scores ranging from 82/100 to 94/100. Patellar redislocation was observed in 8.33% (8 of 96) patients.

CONCLUSION

Hardware-free MPFL reconstruction with or without associated soft-tissue or bony realignment procedures provided reliable clinical improvements and was associated with a low rate of redislocation in patients with recurrent patellofemoral instability. Advantages such as safety, femoral physis preservation, and comparable complication profiles with implant-based techniques endorse its implementation. Orthopedic surgeons in cost-sensitive environments may also benefit their patients with lower costs, no need for implants, lack of implant-related complications, or surgery for implant removal.

LEVEL OF EVIDENCE

Level IV.

Changes in patellar morphology following surgical correction of recurrent patellar dislocation in children

Background

The aim of this study was to evaluate patellar morphological changes following surgical correction of recurrent patellar dislocation in children.

Methods

A total of 35 immature children aged 5 to 10 years who suffered from bilateral recurrent patellar dislocation associated with abnormal patella morphology were enrolled in this study. The knees with the most frequent dislocations (treated with medial patellar retinacular plasty) were selected as the study group (SG), and those undergoing conservative treatment for the contralateral knee were selected as the control group (CG). Computed tomography (CT) scans were performed on all children preoperatively and at the last follow-up to evaluate morphological characteristics of the patella.

Results

All the radiological parameters of the patella showed no significant difference between the two groups preoperatively. At the last follow-up for CT scans, no significant differences were found for the relative patellar width (SG, 54.61%; CG, 52.87%; P = 0.086) and the relative patellar thickness (SG, 26.07%; CG, 25.02%; P = 0.243). The radiological parameters including Wiberg angle (SG, 136.25°; CG, 122.65°; P < 0.001), modified Wiberg index (SG, 1.23; CG, 2.65; P < 0.001), and lateral patellar facet angle (SG, 23.35°; CG, 15.26°; P < 0.001) showed statistical differences between the two groups.

Conclusions

The patellar morphology can be improved by early surgical correction in children with recurrent patellar dislocation. Therefore, early intervention is of great importance for children diagnosed with recurrent patellar dislocation.

Clinical validation of the Oswestry-Bristol Classification as part of a decision algorithm for trochlear dysplasia surgery

AIMS

The Oswestry-Bristol Classification (OBC) is an MRI-specific assessment tool to grade trochlear dysplasia. The aim of this study is to validate clinically the OBC by demonstrating its use in selecting treatments that are safe and effective.

METHODS

The OBC and the patellotrochlear index were used as part of the Oswestry Patellotrochlear Algorithm (OPTA) to guide the surgical treatment of patients with patellar instability. Patients were assigned to one of four treatment groups: medial patellofemoral ligament reconstruction (MPFLr); MPFLr + tibial tubercle distalization (TTD); trochleoplasty; or trochleoplasty + TTD. A prospective analysis of a longitudinal patellofemoral database was performed. Between 2012 and 2018, 202 patients (233 knees) with a mean age of 24.2 years (SD 8.1), with recurrent patellar instability were treated by two fellowship-trained consultant sports/knee surgeons at The Robert Jones and Agnes Hunt Orthopaedic Hospital. Clinical efficacy of each treatment group was assessed by Kujala, International Knee Documentation Committee (IKDC), and EuroQol five-dimension questionnaire (EQ-5D) scores at baseline, and up to 60 months postoperatively. Their safety was assessed by complication rate and requirement for further surgery. The pattern of clinical outcome over time was analyzed using mixed regression modelling.

RESULTS

In all, 135 knees (mean age 24.9 years (SD 9.4)) were treated using a MPFLr. Ten knees (7.4%) required additional surgery. A total of 50 knees (mean age 24.4 years (SD 6.3)) were treated using MPFLr + TTD. Ten (20%) required additional surgery. A total of 20 knees (mean age 19.5 years (SD 3.0)) were treated using trochleoplasty + TTD. Three patients (15%) required additional surgery. In each treatment group, there was a significant improvement in Kujala, IKDC, and EQ-5D at one year postoperatively (p < 0.001) with a recognized level of overall complication rate.

CONCLUSION

The OBC is a valid assessment tool to grade patients with trochlear dysplasia and, when used as part of the OPTA, helps to determine treatments that are safe and effective. This fulfils the requirements for its application in mainstream clinical practice. Cite this article: Bone Joint J 2021;103-B(10):1586-1594.

Conservative versus tailored surgical treatment in patients with first time lateral patella dislocation: a randomized-controlled trial

Background

Patellar instability has a high incidence and occurs particularly in young and female patients. If the patella dislocates for the first time, treatment is usually conservative. However, this cautious approach carries the risk of recurrence and of secondary pathologies such as osteochondral fractures. Moreover, there is also risk of continuous symptoms apparent, as recurrent patella dislocation is related to patellofemoral osteoarthritis as well. An initial surgical treatment could possibly avoid these consequences of recurrent patella dislocation.

Methods

A prospective, randomized-controlled trial design is applied. Patients with unilateral first-time patella dislocation will be considered for participation. Study participants will be randomized to either conservative treatment or to a tailored patella stabilizing treatment. In the conservative group, patients will use a knee brace and will be prescribed outpatient physical therapy. The surgical treatment will be performed in a tailored manner, addressing the pathologic anatomy that predisposes to patella dislocation.

The Banff Patellofemoral Instability-Instrument 2.0, recurrence rate, apprehension test, joint degeneration, and the Patella Instability Severity Score will serve as outcome parameters. The main analysis will focus on the difference in change of the scores between the two groups within a 2-year follow-up.

Statistical analysis will use linear mixed models. Power analysis was done for the comparison of the two study arms at 2-year follow-up with regard to the BPII Score. A sample size of N = 64 per study arm (128 overall) provides 80% power (alpha = 0.05, two-tailed) to detect a difference of 0.5 standard deviations in a t-test for independent samples.

Discussion

Although several studies have already dealt with this issue, there is still no consensus on the ideal treatment concept for primary patellar dislocation. Moreover, most of these studies show a unified surgical group, which means that all patients were treated with the same surgical procedure. This is regarded as a major limitation as surgical treatment of patella dislocation should depend on the patient’s anatomic pathologies leading to patellar instability. To our knowledge, this is the first study investigating whether patients with primary patella dislocation are better treated conservatively or operatively with tailored surgery to stabilize the patella.

Trial registration

The study will be prospectively registered in the publicly accessible database www.ClinicalTrials.gov.

Pedicled Strip of Quadriceps Tendon Graft for Primary Medial Patellofemoral Ligament Reconstruction in Recurrent Patellofemoral Instability: A Systematic Review

PURPOSE

A systematic review of the literature was conducted to ascertain advantages and limitations, update current evidences, and investigate the role of a pedicled quadriceps tendon autograft for primary medio-patellofemoral ligament (MPFL) reconstruction in patients with recurrent patellofemoral instability.

METHODS

The present systematic review was performed according to the PRISMA guidelines. The literature search was conducted in September 2020. All the clinical studies investigating the role of a pedicled strip of quadriceps tendon autograft for primary MPFL reconstruction in patients with recurrent patellofemoral instability were considered for inclusion. Studies investigating the role of MPFL reconstruction combined with additional surgical procedures except for lateral retinacular release were excluded. The methodological quality assessment was performed through the modified Coleman Methodology score.

RESULTS

Data from 9 articles (191 procedures) were retrieved. The mean follow-up was 12 to 38 months. The mean age of the patients was 11.5 to 25.2 years. One hundred twenty of 191 patients were female. All clinical scores showed significant improvement following the procedures. The Kujala score improved of 32.52% points (P < 0.0001), the Lysholm score of 23.74% (P = 0.006), the Tegner scale improved of 8.6% (P = 0.02). Concerning complications, after surgery the apprehension test was positive in 5 of 166 patients, and persistent joint instability was found in 5 of 149 patients. No patient experienced any re-dislocations or underwent reoperations.

CONCLUSIONS

The use of pedicled strip of quadriceps tendon as graft for MPFL reconstruction is a suitable choice in patients with recurrent patellar instability. Although frequently associated with a lateral release, it is unclear whether the latter is necessary for the success of the technique. Appropriately powered randomized controlled trials comparing this graft source to the others commonly used are necessary to at least ascertain the noninferiority of this graft to the others.

LEVEL OF EVIDENCE

IV, Systematic review of Level III-IV studies.

Age at surgery is correlated with pain scores following trochlear osteotomy in lateral patellar instability: a cross-sectional study of 113 cases

Background

A trochlear osteotomy aims to restore patellar stability in patients with recurrent patellar instability and trochlear dysplasia. The age of patients at time of surgery could be a relevant factor which influences outcome. We hypothesized that lower age at time of surgery is associated with better patient-reported outcomes.

Methods

A retrospective study was conducted on patients with patellar instability and trochlear dysplasia. Patients were contacted by phone for informed consent and were then asked to complete online patient-reported outcome measurements (PROMs). The PROMs consisted of the Kujala Knee Score (KKS) (Kujala et al., Arthroscopy 9(2):159-63, 1993; Kievit et al. Knee Surg Sports Traumatol Arthrosc. 21(11):2647-53, 2013), the Short Form 36-item health survey (SF-36v1) (Ware, Med Care 73-83, 1992; Aaronson et al., J Clin Epidemiol. 51(11):1055-68, 1998), and visual analog scale (VAS) scoring pain, instability, disability, and satisfaction on a 0–100 scale. Multivariable linear regression models were used to study the effect of age on the PROM scores.

Results

For this study, 125 surgical procedures in 113 patients were included. Mean VAS pain at rest was 19 and at activity 38; mean Kujala score was 73. Multivariable regression analysis revealed that age at the time of surgery was correlated with VAS pain at rest, with a 0.95 increase of VAS score (scale 0–100) for every year of age. Recurrence of instability was observed in 13 (10%) knees.

Conclusion

In this cross-sectional study, pain scores of 113 patients who have undergone a lateral facet elevating trochlear osteotomy for patellar instability were reported. Age at time of surgery was correlated with an increased pain score at rest with an average of 9.5 points (scale 0–100) for every 10 years of age. Age at time of surgery was not correlated with overall satisfaction.

Prognostic factors for isolated medial patellofemoral ligament reconstruction: A systematic review

BACKGROUND

Evidence concerning the influence gender, age, and the time elapsed from the first dislocation to surgery in the outcomes of Medial Patella Femoral Ligament (MPFL) reconstruction are lacking. This systematic review was conducted to investigate whether patient characteristics have an influence in the clinical outcomes of MPFL reconstruction for patients with patellofemoral instability.

MATERIAL AND METHODS

This study followed the PRISMA guidelines. The main databases were accessed in February 2021. All the studies reporting outcomes of primary MPFL reconstruction in patients with recurrent patellofemoral instability were considered for inclusion. A multivariate analysis diagnostic tool was used to analyse the association between age, gender and time from injury to surgery and the surgical outcomes at last follow-up.

RESULTS

A total of 50 articles (2037 procedures) were included. The mean follow-up was 40.90 ± 24.8 months. The mean age was 23.6 ± 3.9 years. 64.3% (1309 of 2037 patients) were female. The mean time from injury to surgery was 64.5 ± 48.9 months. Women showed no statistically significant association with the Kujala score or complications. Older patients had a reduced risk to incur re-dislocations (P = 0.01) and revisions (P = 0.01). Longer time from injury to surgery was associated with greater risk to incur re-dislocations (P = 0.01), and with lower Kujala score (P < 0.0001). No other statistically significant association was evidenced.

CONCLUSION

The time span from the first patellar dislocation to the surgical reconstruction was a negative prognostic factor, while sex had no influence on surgical outcomes. The role of patients age on surgical outcomes remains unclear.

Novel method for diagnosing lateral patellar compression syndrome using X-ray: a retrospective case-control study

Background

A well-established reference is lacking for diagnosing lateral patellar compression syndrome (LPCS), and this diagnosis currently depends on clinicians' subjective judgment and several examination results. X-rays are primarily used to diagnose LPCS, but they have low detection rates of patellar tilt using the congruence angle (CA) and patellar tilting angle (PTA).

Methods

We enrolled 87 patients (31 men and 56 women; mean age: 42.11±15.33 years) between 2016 and 2019 and divided them as per diagnosis into three groups of 29 each: LPCS, patellar dislocation (PD, control), and meniscus tear (MT, negative control) groups. A senior radiologist and the chief physician of sports medicine examined their patellar axial radiographs of the knee in 30° flexion using a computer imaging system, measuring LPCA, CA and PTA. Univariate analysis of variance and Kruskal-Wallis H test were used to compare measurement data with normal distribution and non-normal distribution, respectively. Bonferroni correction was used to analyze different indicators for different groups. The area under the curve (AUC) was calculated to verify the value of LPCA in the initial diagnosis of LPCS.

Results

LPCA (19.88±7.49) was significantly higher in LPCS group than in MT (13.68±4.69) and PD groups (10.16±4.43) (P<0.01) and was also significantly higher on affected side than on healthy side (16.44±5.00) (P=0.04). LPCA >13.9° had sensitivity and specificity of 89.66% and 68.97%, respectively, for LPCS diagnosis (AUC: 0.82, 95% confidence interval: 0.719-0.891, P<0.001).

Conclusions

We demonstrated that LPCA measured using an axial patellar radiograph of the knee in 30° flexion is high in patients with LPCS, and it may be used for diagnosing LPCS.

The majority of patellar avulsion fractures in first-time acute patellar dislocations included the inferomedial patellar border that was different from the medial patellofemoral ligament attachment

PURPOSE

Accurate assessment of the locations of patellar avulsion fractures in acute patellar dislocations is clinically relevant for decision making for treatment. The study aim was to classify the locations of patellar avulsion fractures with a focus on the ligament attachments of medial stabilizing structures.

METHODS

Out of 131 first-time acute traumatic patellar dislocations, 61 patients had patellar fractures. Subsequently, 10 patients with isolated osteochondral fractures of the articular surface in the patella were excluded. Finally, 51 patients (34 females and 17 males, average age: 18.5 years, 95% CI 16.1-20.9) were included in the study cohort. Based on the locations of the patellar attachment, the patients were divided into three groups: the superior group [medial patellofemoral ligament (MPFL) attachment], inferior group [medial patellotibial ligament (MPTL)/medial patellomeniscal ligament (MPML) attachment], and mixed group.

RESULTS

In the patellar avulsion group (51 patients), the superior group, mixed group, and inferior group contained 8/51 (16%), 12/51 (24%), and 31/51 (61%) patients, respectively.

CONCLUSIONS

This study showed that 84% of the patellar avulsion fractures were located in the inferomedial patellar border, which consisted of MPTL/MPML attachments that were clearly different from the true "MPFL" attachment at the superomedial patellar border. In terms of the clinical relevance, the acute surgical repair of MPTL/MPML attachments in the inferomedial patellar border may not sufficiently control the patella if optimal management of the MPFL is not performed.

LEVEL OF EVIDENCE

IV.

Combined medial patellofemoral and medial patellotibial reconstruction for patellar instability: a PRISMA systematic review

BACKGROUND

The medial patellofemoral ligament (MPFL) works in association with the medial patellotibial ligament (MPTL) and the medial patellomeniscal ligament (MPML) to impart stability to the patellofemoral joint. The anatomy and biomechanical characteristics of the MPFL have been well described but little is known about the MPTL and MPML. Several reconstruction procedures of the MPFL with semitendinosus, gracilis, patellar and quadriceps tendons, allografts and synthetic grafts have been described. No clear superiority of one surgical technique over another is evident.

METHODS

A systematic review of the literature was conducted using PRISMA guidelines. Inclusion criteria were articles that reported clinical outcomes of combined reconstruction of MPTL and MPFL. The methodological quality of the articles was determined using the modified Coleman Methodology Score (CMS).

RESULTS

Nine articles were included, reporting the clinical outcomes of 197 operated knees. The surgical procedures described include hamstrings grafting and transfer of the medial patellar and quadriceps tendons with or without bony procedures to reconstruct the MPTL in association with the MPFL. Overall, good and excellent outcomes were achieved. The median CMS is 70.6 ± 14.4 (range 38 to 84).

CONCLUSION

Different techniques are reported, and outcomes are good with low rates of recurrence. The quality of the articles is variable, ranging from low to high. Appropriately powered randomized controlled trials are needed to better understand what the adequate indications for surgery in patients with patellar instability and clinical outcomes are. Combined reconstruction of MPFL and MPTL leads to favourable clinical outcomes, supporting its role as a valid surgical procedure for patellar stabilization.

Evaluation of risk correlation between recurrence of patellar dislocation and damage to the medial patellofemoral ligament in different sites caused by primary patellar dislocation by MRI: a meta-analysis

Purpose

Non-surgical treatment of primary patellar dislocation has a high risk of recurrent dislocation; thus, we tried to identify injuries in which sites of the medial patellofemoral ligament (MPFL) were most associated with recurrent dislocation by analyzing relevant original literature in order to provide improved suggestions on early surgical treatment.

Methods

According to the preset retrieval strategy, the original studies were retrieved until January 2020 using MEDLINE, Embase and Cochrane Library. Review Manager 5.3 software was used to summarize and compare the differences of recurrent dislocation of MPFL injuries at different attachments.

Results

Although the incidence of recurrent patellar dislocation at the femoral attachment of MPFL was higher overall (femoral only vs. patellar only vs. combined: 37.6% vs. 32.3% vs. 35.8%), no statistical difference was found among the three groups (femoral only vs. patellar only, RR = 1.32 [95% CI 0.89–1.95]; P = 0.17) (femoral only vs. combined, RR = 1.15 [95% CI 0.59–2.22]; P = 0.68) (patellar only vs. combined, RR = 0.94 [95% CI 0.69–1.29]; P = 0.72). In addition, the sulcus angle of recurrent dislocation group is significantly greater than that in the non-recurrent dislocation group (MD = 3.06 [95% CI 0.42–5.70]; P = 0.02).

Conclusions

Based on the pooled data collected from the original studies available, the risk of recurrent patellar dislocation due to damage to the MPFL at different sites did not differ. Additionally, the sulcus angle in the group with recurrent dislocation was considerably higher when comparing with the group without recurrent dislocation, that is, the shallower and flatter of the trochlear groove, the higher the risk of recurrent patellar dislocation.

Combined medial patellofemoral and patellotibial reconstruction with soft tissue fixation in recurrent patellar dislocation

INTRODUCTION

The medial patellofemoral and patellotibial ligaments (MPFL and MPTL) are the main passive restraints to lateral patellar translation. When nonoperative management of patellofemoral dislocations fails, surgical options can be considered to restore patellofemoral stability. Several reconstruction procedures of the MPFL with semitendinosus, gracilis, quadriceps tendon, and synthetic grafts have been described. No clear superiority of one surgical technique over another is evident.

MATERIALS AND METHODS

Patients who suffered at least two documented episodes of unilateral patellar dislocation, confirmed radiographically and at clinical examination, underwent combined MPFL and MPTL reconstruction. Patients were regularly followed-up postoperatively at 2, 4, 8, 12, and 24 weeks, and then annually for a minimum of 2.5 years. Clinical and functional evaluations were performed using the modified Cincinnati rating system and the Kujala score, while anthropometry values including thigh volume and cross-sectional area of the thigh were measured before the operation and at the latest follow-up bilaterally.

RESULTS

There were 7 males and 27 females with a mean age of 26.5 ± 10.7 years (range, 13-39 years). The mean follow-up was 3.1 years (range, 2.5-4 years). The mean modified Cincinnati score Increased from 51 ± 22 preoperatively to 90 ± 19 (P = .001). The mean Kujala scores increased from 47 ± 17 preoperatively to 82 ± 17 (P = .02), with no significant differences between patients with or without osteochondral lesions (P ≥ .05), and between male and female patients (P ≥ .08). The Insall-Salvati index was 1.1 preoperatively and remained within normal range (P = .05) at the latest follow-up.

CONCLUSION

Combined reconstruction of MPFL and MPTL using an ipsilateral autologous gracilis tendon is satisfactory and effective and can be considered as suitable management option to treat recurrent dislocation of the patella. However, randomized studies are needed to compare different techniques.

STUDY DESIGN

Case series.

Factors Associated With an Increased Risk of Recurrence After a First-Time Patellar Dislocation: A Systematic Review and Meta-analysis

BACKGROUND

Recurrent dislocations after a first-time lateral patellar dislocation may occur in more than 50% of patients and can cause long-term disability. Many factors have been suggested to influence the risk of recurrence.

PURPOSE

To systematically review and quantitatively synthesize the literature for factors associated with an increased risk of recurrence after a first-time patellar dislocation.

STUDY DESIGN

Systematic review and meta-analysis of observational studies.

METHODS

A total of 4 electronic databases were searched to identify relevant studies published before February 7, 2019. A quality assessment was performed with the National Heart, Lung, and Bone Institute quality assessment score. Factors assessed for their effect on the recurrence rate were documented, and the rates of recurrence were compared. Pooled dichotomous data were analyzed using random-effects meta-analysis with odds ratios (ORs).

RESULTS

A total of 17 studies met the criteria for inclusion. The overall rate of recurrent dislocations after a first-time lateral patellar dislocation was 33.6%. An increased risk of recurrence was reported in patients with a younger age (OR, 2.61; P < .00001), open physes (OR, 2.72; P < .00001), trochlear dysplasia (OR, 4.15; P = .009), an elevated tibial tuberosity-trochlear groove (TT-TG) distance (OR, 2.87; P < .00001), and patella alta (OR, 2.38; P = .004). Sex, patterns of medial patellofemoral ligament injury, and history of contralateral dislocations were not found to be associated with an increased recurrence rate (P≥ .05). In studies that reported on the presence of multiple risk factors, recurrence rates were 7.7% to 13.8% when no risk factors were present but increased to 29.6% to 60.2% when 2 risk factors were present and to 70.4% to 78.5% when 3 risk factors were present.

CONCLUSION

Younger age, open physes, trochlear dysplasia, elevated TT-TG distance, and patella alta were key risk factors for the recurrence of lateral patellar dislocations. Despite being not infrequently cited as risk factors, patient sex and a history of contralateral dislocations were not found to be significant risk factors. The presence of multiple risk factors increased the risk, and the development of predictive instability scores in large patient cohorts using all established risk factors should be a focus of future studies.

Scoring system for optimal management of acute traumatic patellar dislocation: A multicenter study

BACKGROUND

In first-time acute traumatic patellar dislocations, numerous anatomic and clinical factors are complicatedly associated and should be comprehensively considered for the optimal management of conservative or surgical intervention. The purpose of this study was to establish a scoring system, using a concept that is not complicated and easily used in clinic.

METHODS

Of 131 first-time acute traumatic patellar dislocations, 81 patients (51 females, 30 males) with an average age of 19.6 (95%CI, 17.5-21.6) years and an average follow-up duration of 17.1 (95% CI, 12.3-21.9) months, who underwent conservative treatment after first-time dislocations, were reviewed. Based on the odds ratios applying logistic regression analysis, the scoring system was established.

RESULTS

The scoring system (total: 10 points) had simple composition of age <20 (2 points), sports injury (1 points), hemarthrosis (1 points), and image findings of a bony fragment (3 points), lateral shift of the patella (1 points), and trochlear dysplasia (2 points). A threshold score of 6.5 was determined using the area under receiver operating characteristic curve of 0.893 (p < 0.0001). In logistic regression analysis, a score of ≥7 was shown to be a dominant factor for recurrence (OR = 27.1, p < 0.0001). Furthermore, the association between the score and recurrence risk was as follows: a score of ≤4 = low risk (1/21 cases, 5%); a score of 5-7 = medium risk (13/27 cases, 48%); a score of ≥8 = high risk (30/33 cases, 91%).

CONCLUSIONS

Based on the simple scoring system, patients who scored ≥8 were considered suitable for surgical treatment because of the high rate of recurrence, whereas those who scored ≤4 were considered suitable for conservative treatment because of the low rate of recurrence.

Surgical management for recurrent patellar dislocations in skeletally immature patients

BACKGROUND

Due to his multifactorial aetiology, treating patellofemoral instability can be a challenge for the orthopaedic surgeon. The incidence of patellofemoral instability shows a peak during adolescence, especially from 11 to 14 years old.

AIM

Several clinical studies focusing on recurrent patellar dislocations in skeletally immature patients have been published, reporting inconsistent or controversial results. Currently, there is a lack of consensus regarding the surgical management of these patients. The purpose of this study is to update current evidence and systematically review indications, treatments, and outcomes of surgical management for recurrent patellar dislocations in skeletally immature patients.

METHODS

A comprehensive review of the literature was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis, the PRISMA Statement. The following electronic databases were accessed in February 2019: PubMed, Scopus, Google Scholar, CINAHL, EMBASE. All the articles treating surgical management for recurrent patellar dislocations in skeletally immature patients were considered for inclusion. For the methodological quality assessment, we referred to the Coleman Methodology Score (CMS). For the statistical analysis, we referred to the unpaired t-test to establish whether the results are statistically significant.

RESULT

The overall CMS resulted in 52.78 points, attesting a satisfactory methodological quality assessment to this systematic review. A total of 21 articles including 623 patients (577 knees) were evaluated. The overall mean age was 13.02 years. The mean follow-up was 46.61 months. The mean Kujala score improved from 58.94 ± 10.38 to 87.07 ± 7.68 points. The Lysholm score reported a pre- and post-operative mean values of 49.54 ± 14.20 and 88.32 ± 8.80, respectively. The mean Tegner Activity Scale scored 4.28 ± 1.22 at baseline, improving to 5.26 ± 0.83 post-operatively. A total of 4.19% of patients incurred into a major complication, while 9.6% sustained a minor one. We observed a total of 89 re-dislocations above 692 treated knees (12%).

CONCLUSION

The main findings of this study are that surgical procedures for skeletally immature patients affected by recurrent patellar dislocations are feasible and effective. Complications and re-dislocations occurred infrequently. It is of fundamental importance to treat precociously these patients in order to reduce the risk of further recurrences, to increase the level of sporting activity and improving the quality of life.

Editorial Commentary: Standing the Test of Time and Sport: Fulkerson Tibial Tubercle Osteotomy of the Knee

A biplanar osteotomy aiming to anteromedialize the anterior tibial tuberosity to realign the patellofemoral joint described by Prof. Fulkerson is one of the classical operations to address many pathologies of the patellofemoral joint. The procedure is evidence-based and effective for the management of patellofemoral pain and osteoarthritis, confirming that the original ideas and concepts are still valid, and still stand strong. In high-demand patients, the Fulkerson osteotomy offers good opportunities of success in terms of return to sport. With the right indications, patients will gain several years of pain-free sports participation.

Medial Patellofemoral Ligament Reconstruction Using All-Soft Suture Anchors for Patellar Fixation

The medial patellofemoral ligament (MPFL), which is critical for both patellar stability and normal kinematics of the patellofemoral joint, is disrupted in most patellar dislocations. Consequently, MPFL reconstruction is advocated in recurrent dislocations to restore native patellar constraints. Fixation of the MPFL graft to the medial border of the patella can be achieved through various methods, each with its own benefits and drawbacks. We present a technique for MPFL fixation to the patella using all-soft suture anchors, theoretically decreasing the risk of patellar fracture and articular surface violation.

I performed experiments and I have results. Wow, and now?

Writing a scientific article is not an easy task, but it is definitely a great satisfaction to be able to conclude and publish it. Indeed, each publication is a service we make to the entire scientific community and to the advancement of science even before our personal career. There is and there will not be a final book/article for writing a scientific paper. Therefore, some knowledge is a decisive factor to increase the chances of our work being accepted by a specialized scientific journal. The purpose of this editorial is to trace an ideal path, based on our personal experience, useful to properly structure a scientific article, from bibliographic research to cover letter. Articles should not be written in a polished way to gratify one's own ego, but they must be written for anyone who can read and understand them.

LEVEL OF EVIDENCE

V.