A Computational Approach to Optimize Surgical Intervention for Patients with Recurrent Patellar Dislocation on a Subject-Specific Basis

Objective To evaluate the clinical efficacy of autologous semitendinosus tendon and double bundles reconstruction of medial patellofemoral ligament(MPFL) in the treatment of recurrent patellar dislocation without bone deformity. Methods The retrospective analysis was performed on the clinical data of 12 patients with recurrent patellar dislocation without bone deformities who were reconstructed by autologous semitendinosus tendon in Wuhu Hospital of Traditional Chinese Medicine from June 2015 to December 2017, including 2 males and 10 females, aged 14-46(27.75±10.14) years. All patients whose lateral patellar anchor nail fixed graft using two belt line, the femur after adjusting the tension side under arthroscopy using extrusion screw implant interface, postoperative 1, 3, 6 and 12 months follow-up, subjective evaluation of patellofemoral joint friction feeling, patellar abnormal activities, patellar extrapolation experiment and extrapolation of fear, the knee joint motion, muscle strength test. Imaging(X-ray) was used to evaluate the position of the bone tract, and Lysholm, Tegner and Kujala scores were used to evaluate the knee function before and after surgery. Results All 12 patients were successfully operated, and were followed up for 12 to 24 months, mean 13.5 months. No patella redislocation or patella dislocation were found after operation.0° and 30° bend knees a patellar extrapolation experiment and extraopolation fears were negative. The lysholm score was preoperative 66.00±4.71 and the final follow-up 92.67±3.23.Tegner score was preoperative 3.33±0.89 and the final follow-up 5.33±0.78.The subjective scores of Kujala were preoperative 53.67 ±3.23 and final follow-up 91.50±2.68, with statistically significant differences(t=16.248, 32.176, 89.350, all P values<0.01). Conclusions MPFL is a safe, effective and reliable method and can achieve satisfactory clinical result for the reconstruction of MPFL with autologous semitendinosus tendon and double beam anatomic reconstruction in patients with recurrent patrllar dislocation. Key words: Patella dislocation; Recurrent patellar dislocation; Medial patellofemoral ligament; Reconstructive surgical procedures

After first-time lateral patellar dislocation, 44% to 70% of patients sustain redislocations. Increased femoral anteversion (FA) is considered to result in increased lateralizing forces on the patella, which might predispose one to patellar instability. When recurrent patellar dislocations (RPDs) are bilateral, it is unclear if the FA is even more increased. Patients with bilateral RPD would have greater FA than patients with unilateral RPD. Case-control study; Level of evidence, 3. A total of 52 skeletally mature patients with RPD and a clinical suspicion of rotational malalignment underwent rotational computed tomography or magnetic resonance imaging. The uni- or bilaterality of the RPD was determined. A control group comprising 54 adult patients with trauma underwent computed tomography of both lower extremities as part of a multitrauma protocol. The FA values of both lower extremities were evaluated separately. In total, 20 of 52 (38.5%) patients in the study group had a history of unilateral RPD and 32 of 52 (61.5%) patients had a bilateral RPD diagnosis. The mean FA of the asymptomatic limb in unilaterally symptomatic patients was 18.0° (SD, 11.2°; range, 0.5°-40.0°; median, 16.5°). In the symptomatic limb, the mean FA was 19.2° (SD, 9.1°; range, 2.0°-33.0°; median, 19.0°) (mean difference, 1.2°; 95% CI -1.3° to 3.8°). In bilaterally symptomatic patients, the mean FA on the right side was 23.2°, and 22.5° on the left. The mean differences between the symptomatic limbs in the unilateral RPD group and the right or left limbs in the bilateral RPD group were 4.0° (P = .263) and 3.3° (P = .326), respectively. In the control group without RPD, the mean FA was 12.5° (SD, 8.5°; range, 0.8°-33.0°; median, 10.9°). The mean difference between right limbs of the patients with bilateral RPD and right limbs of controls was 10.8° (P = .001). Patients with bilateral RPD have bilaterally greater FA than patients without a history of RPD. Patients with unilateral RPD have greater FA on both sides compared with the control group without a history of lateral patellar dislocation. No statistically significant difference of FA can be seen between patients with bilateral or unilateral RPD.

PurposeLangenskiöld described a reconstructive soft-tissue procedure for irreducible lateral congenital patellar dislocations. Paley further detailed the technique in the surgical management of congenital femoral deficiency. The aim of this study was to evaluate the outcomes of patients with congenital, chronic and recurrent patellar dislocations treated with the modified Langenskiöld procedure.MethodsThis is a retrospective case series. Between 2011 and 2018, 18 knees in 13 patients (mean age 15.8 years (sd 4.4; 12 to 29.9), nine female) with diagnoses of recurrent (six patients, eight knees), chronic (four patients, six knees) and congenital (three patients, four knees) patellar dislocations were treated with the modified Langenskiöld procedure.ResultsThere were no recurrent lateral dislocations in the congenital or recurrent groups. One of the patients in the congenital group had an overcorrection with some medial patellar maltracking but until this time has not required any further surgery. In the chronic group two of the six knees developed further dislocations; these were both on the same patient, who had no dislocations until one year after surgery. Mean Kujala score was 83.7 (sd 17; 47 to 100) for all groups. In spite of preoperative knee flexion contractures of up to 30° in three patients (six knees), all patients had full extension postoperatively. Eight patients reported being satisfied with their outcome, one was somewhat satisfied, two were very dissatisfied, and two did not respond.ConclusionThe modified Langenskiöld reconstruction provides a powerful correction for challenging cases of congenital and recurrent patellar dislocations. Re-dislocation as well as overcorrection can occasionally occur.Level of EvidenceLevel IV

Medial patellofemoral ligament (MPFL) reconstruction is a well-established treatment option in recurrent patella dislocation. The combination with associated retropatellar cartilage lesions are severe injuries and very difficult to treat. The purpose of this study was to evaluate our clinical results of MPFL reconstruction and autologous chondrocyte implantation (ACI). Thirteen patients with recurrent patella dislocation were treated with a combination of MPFL reconstruction and ACI at our institution between 2010 and 2014. All patients had at least 2 patella dislocations. The posttraumatic cartilage lesions were grade IV according to the ICRS and were localized retropatellar in 8 cases and at the lateral femoral condyle in 2 cases. The mean defect size was 7.2±3.5 cm2 (3-12 cm2). Subjective and objective scores were assessed before surgery and at f/u, as well as radiologic parameters and cartilage status on magnetic resonance imaging (MRI). Ten patients (5 male, 5 female) with a mean follow-up of 2 years (minimum 1 year to 4 years) were enrolled in the study. At latest clinical follow-up, all patients had a stable patella with no signs of instability and all patients showed improved subjective and objective scores. Lysholm score increased to 74.1±18.7 (48-99), KOOS score to 74.4±16.9 (57-95), IKDC subjective to 63.9±22.1 (34-93) and Kujala score to 73.8±25.1 (50-100). The post-operative modified MOCART score for quality assessment of the ACI on MRI was an average of 13.7±1.8 points (11-16), with a complete fill of the defect in 80% of lesions. Medial patellofemoral ligament reconstruction with simultaneous ACI showed good clinical results in recurrent patella dislocation with traumatic cartilage lesions grade IV. No patella re-dislocation occurred and the ACI was successful in 80% of patients according to MRI. Subjective and objective scores improved but combined surgery is inferior to reports from the literature on MPFL reconstruction alone without cartilage damage. Therapeutic case series, Level IV.

Femoral trochlear dysplasia is an anatomic deformity that predisposes patients to patellar instability, including patellar subluxation and dislocation, and can lead to severe patellofemoral joint degeneration if left untreated. Femoral trochlear dysplasia leading to recurrent bilateral patellar dislocation has rarely been reported as having a familial association. Orthopedic surgeons who encounter patients presenting with chronic patellar instability with no underlying disease or syndrome should be aware of the presence of femoral trochlear dysplasia leading to recurrent bilateral patellar dislocation. Although femoral trochlear dysplasia remains uncommon, the presence of bilateral recurrent patellar dislocation in multiple members of the same family is highly suggestive of genetic inheritance.This article describes 3 patients from 1 family who presented with femoral trochlear dysplasia leading to recurrent bilateral patellar dislocation. To our knowledge, this is the second article to describe a familial form of femoral trochlear dysplasia associated with recurrent bilateral patellar dislocation and is the first article in English. A lower threshold for screening and early intervention for symptomatic family members may be indicated to prevent the long-term effects of chronic patellar subluxation, dislocation, and patellofemoral arthritis.

The purpose of this study was to investigate the Danish population as a whole from 1994 to 2013 to find the incidence of acute and recurrent patellar dislocation. The study was performed as a descriptive epidemiological study. The Danish National Patient Registry was retrospectively searched from 1994 to 2013 to find the number of acute and recurrent patellar dislocation. National population data were collected from Statistics Denmark. The period 1994-2013 saw a total registration of 24,154 primary patellar dislocations. A mean incidence of 42 (95% CI 37-47) per 100,000 person-years at risk was found, and young females aged 10-17 had the highest incidence of 108 (95% CI 101-116). In a 10-year follow-up, patients were at an overall risk of 22.7% (95% CI 22.2-23.2) of suffering a recurrent dislocation, with young girls aged 10-17 experiencing the highest risk, namely 36.8% (95% CI 35.5-38.0). The overall risk of suffering a patellar dislocation in the contralateral knee was 5.8% (95% CI 5.5-6.1) and 11.1% (95% CI 10.4-11.7) for patients aged 10-17. A high incidence rate of primary patellar dislocation was found both as a mean in the population (42/100,000), and particularly in patients aged 10-17 (108/100,000). The risk of recurrent dislocation in the affected knee (22.7%) and the contralateral knee (5.8%) was high, which could indicate the influence of an underlying pathomorphology. This is relevant knowledge to the clinician, as he/she should be aware of the high risk of recurrent dislocation when deciding on treatment, especially in young patients. IV.

Combined Medial Patellofemoral Ligament and Medial Patellotibial Ligament Reconstruction for Recurrent Lateral Patellar Dislocation in Flexion

Objectives:Medial patellofemoral ligament (MPFL) reconstruction is commonly performed in patients with recurrent patellar dislocations and associated instability. However, though general outcomes and when to perform concomitant surgical procedures such as a tibial tubercle osteotomy (TTO) have been studied, there remains limited information on the effects of underlying mental health conditions on baseline and post-operative outcome measures. Given the rising prevalence and number of undiagnosed number of patients with mental health conditions such as major depressive disorder (MDD), recognition that patients with chronic, recurrent patellar dislocations who require MPFL reconstruction may be at risk for inferior post-operative outcomes if they also have a mental health disorder. The purpose of this study is to assess how mental health disorders such as MDD or unrecognized depression can affect pre- and post-operative outcomes in patients undergoing MPFL.Methods:A retrospective, IRB approved review of patients undergoing MPFL reconstruction from 2015 to 2023 was performed. Demographic data, presence of diagnosed mental health disorders, complications, and Patient Reported Outcomes Measurement Information Systems (PROMIS) scores related to their procedure were collected. Exclusion criteria included patients aged <10 or >75 years, or those with incomplete PROMIS data. Patients without a formal diagnosis of MDD, but with a pre-op PROMIS-Dep score greater than or equal to 52.5 were considered PROMIS-Depressed. Kruskal-Wallis and chi-squared tests were used to compare continuous and categorical cohort descriptive statistics respectively. Logistic and mixed-effects regression were used to investigate the association between PROMIS T-scores and mental health disorders while adjusting for confounding patient and surgical variables.Results:187 patients met inclusion criteria. Descriptives of cohort variables tabulated by formal mental health disorder assessment are shown in Table 1. Patients with a mental health disorder were more likely to have an underlying connective tissue disease and require longer follow-up (512 vs 713 days, p <0.05). The presence of a mental health disorder led to significantly worse pre-and post-operative PROMIS scores, however there were no differences in the change in PROMIS scores after surgery nor was there a difference in ability to achieve MCID. Relative to patients without any mental health disorder, MDD patients and those PROMIS-depressed reported significantly worse pre- and post-operative PROMIS scores, with those who were PROMIS- depressed particularly doing worse (Figure 1). However, there were no differences in the change in PROMIS scores after surgery (despite depressed and PROMIS-depressed patients having more room for improvement), nor was there a difference in odds of achieving MCID (Figure 2). Regression analysis showed an association between underlying mental health disorders or need for additional procedures and worse average PROMIS scores in all domains. This was also seen with PROMIS-depressed patients, however presence of connective tissue disorders led to worse PROMIS-PI scores in this patient population. In addition, the odds of a reported complication or need to have a contralateral MPFL procedure were higher in patients requiring TTO. Increased age was associated with worse PROMIS-PI and PF scores. Partial correlation of the odds of needing MPFL on the contralateral extremity weakly correlated with lower odds of PROMIS-PI MCID achievement.Conclusions:The most important finding in our study is that underlying mental health disorders do not affect odds of achieving MCID after undergoing MPFL, however they do lead to worse pre- and post-operative PROMIS scores and prevented patients from deriving more improvement from their surgery. This finding was exacerbated in patients who were PROMIS-depressed. Overall, our cohort improved with surgery, but both diagnosed and undiagnosed MDD adversely affects patients who undergo MPFL reconstruction. Requiring a TTO or having an underlying connective tissue disorders may present as additional risk factors. These findings highlight the importance of identifying and addressing mental health in this patient population, especially given the number of patients who did require contralateral MPFL (with subsequently longer recovery times) and therefore may be susceptible to inferior long-term physical function.

PurposeThe primary purpose was to assess sulcus angle (SA) magnetic resonance imaging (MRI) measurements and determine diagnostic cutoff values along four axial levels on cartilaginous and osseous surfaces comparing those with patellar dislocations (PD) versus controls. A secondary aim was to identify differences in SA between patients with one‐time dislocation (OTD) versus recurrent patellar dislocations (RPDs).MethodsPaediatric patients with a history of PD were retrospectively grouped into those with an OTD versus RPDs. Age and sex frequency matching controls (ACL injuries without PD history) were identified. The SA was recorded at four levels in the trochlear groove (TG) on cartilaginous and osseous surfaces. Differences between sample means (PDs vs. controls; RPDs vs. OTDs) were assessed; cutoff values for discriminating PDs from controls were identified utilising Youden′s index.ResultsThere were 173 PDs (106 RPDs, 67 OTDs) and 100 controls. There were differences in mean SA between PD and controls throughout the trochlear groove for both cartilaginous (PD vs. control: SA1 166.1° vs. 152.5°, SA2 161.0° vs. 148.5°, SA3 155.7° vs. 145.9°, SA4 150.7° vs. 142.5°) and osseous surfaces (PD vs. control: SA1 160.2° vs. 146.6, SA2 153.8° vs. 140.2°, SA3 147.2° vs. 134.8°, SA4 142.1° vs. 132.6°) (p < 0.001). Diagnostic cutoffs were higher for cartilaginous versus osseous measurements (SA1 159.6° vs. 153.1°, SA2 153.8° vs. 148.0°, SA3 152.5° vs. 141.6°, SA4 148.1° vs. 137.4°). RPD patients had greater cartilaginous SA than OTDs throughout the TG (SA1p = 0.014, SA2p = 0.004, SA3p = 0.027, SA4p = 0.007), while osseous SA measurements did not differ (SA1p = 0.057, SA2p = 0.070, SA3p = 0.185, SA4p = 0.175).ConclusionsSA was greater in PDs than controls at all four levels in the TG for both cartilaginous and osseous measurements. Cartilaginous SA was greater among RPDs than OTDs at all levels; however, osseous SA was not different between cohorts. The diagnostic cutoff of dysplastic SA differed by axial level and surface.Level of EvidenceLevel III.

Medial patellofemoral ligament reconstruction (MPFLR) is the standard procedure for recurrent lateral patellar dislocation. While low-grade trochlear dysplasia (TD) can be managed conservatively, trochleoplasty is recommended for high-grade TD. However, its indications and efficacy remain debatable. This study evaluates the clinical outcomes of MPFLR without trochleoplasty in patients with TD. 57 patients who underwent MPFLR with a minimum follow-up of two years were included. TD was classified as low-grade (Dejour Type A) or high-grade (Types B, C, D). Patient-reported outcome measures (PROMs)-Kujala, Lysholm, and International Knee Documentation Committee scores were assessed pre and postoperatively and correlated with TD grades. Pre- and postoperative PROMs were also correlated with age, gender, patella alta, patellar cartilage defect, preoperative PROMs, and type of surgery. The mean age at surgery was 26.9years, and 64.9% were female. At a mean follow-up of 72months, no patient experienced a recurrence of dislocation. Postoperative PROMs showed a significant improvement (p<0.001). Patients with low-grade TD had significantly better PROMs compared to those with high-grade TD (p<0.05). While increasing age, cartilage lesions, and trochlear dysplasia had a significant correlation with PROMs, regression analysis revealed that preoperative Kujala score and trochlear dysplasia were major determinants of PROMs. Furthermore, there was no effect of gender, patella alta, or type of surgery on PROMs. Isolated MPFLR significantly improves PROMs and prevents recurrence, even in patients with high-grade TD. Among all variables, Trochlear dysplasia is the most influential determinant of PROMs. III, retrospective cohort study.

The purpose of this study was to evaluate the clinical outcomes of medial patellofemoral ligament (MPFL) reconstruction combined with derotational distal femur osteotomy in patients with recurrent patellar dislocation who had excessive femoral anteversion angle and trochlear dysplasia. Between 2015 and 2020, 64 patients (64 knees) with recurrent patellar dislocation, who had excessive femoral anteversion angle (≥ 25°) and trochlear dysplasia and were surgically treated using derotational distal femur osteotomy and MPFL reconstruction, were eligible for this retrospective study. These patients were assigned to two groups according to the grade of trochlear dysplasia. Group A (type A trochlear dysplasia, n = 33) and Group B (type B, C, D trochlear dysplasia, n = 31). Preoperative and postoperative patellar tilt angle (PTA), Caton-Deschamps index (CD-I), tibial tubercle-trochlear groove (TT-TG) distance and femoral anteversion angle were evaluated. Patient outcomes were assessed using the preoperative and postoperative International Knee Documentation Committee (IKDC) score, Kujala score, Lysholm score, Tegner score, and visual analog scale (VAS) score. A total of 64 patients (64 knees) were evaluated in this study, with a mean follow-up period of 28.4 ± 3.6months. There were no cases of wound infection, osteotomy site fractures, deep venous thrombosis of the lower extremities, or re-dislocation in the two groups during the postoperative follow-up period. All patients returned to full extension and flexion. The postoperative Tegner score, Lysholm score, Kujala score, IKDC score, VAS score, PTA, CD-I, TT-TG distance, and femoral anteversion angle were significantly improved compared with the preoperative status (P < 0.05). There was no significant difference between the two groups (n.s.). MPFL reconstruction combined with derotational distal femur osteotomy showed satisfactory clinical outcomes during follow-up in patients with recurrent patellar dislocation who had excessive femoral anteversion angle and trochlear dysplasia. Even patients with high-grade trochlear dysplasia showed satisfactory results. For those patients, additional surgery is not necessary. Level III.

BackgroundRecurrent lateral patellar dislocation (RLPD) poses a significant threat to patients’ quality of life due to knee pain, patellofemoral cartilage damage, and potential traumatic arthritis. Predictive scoring systems have been developed to assess the risk of RLPD; however, their relative accuracy remains uncertain.PurposeTo investigate the accuracy of the multiple regression models to predict the individual risk of recurrent LPD.MethodsThe Patellar Instability probability calculator (PIP), Recurrent Instability of the Patella Score (RIP), and Patellar Instability Severity Score (PIS) scoring rules were measured in 171 patients with a history of patellar dislocation and 171 healthy individuals. Three prediction models were calculated based on the data to predict the risk of recurrent lateral patellar dislocation. The inter-observer and intra-observer reliability of each measurement parameter was evaluated. The predictive capacity of the three-prediction model was investigated using the receiver operating characteristic curve.ResultsIn the case group of 171 patients, PIS accurately predicted recurrent lateral Patella dislocation in 143 patients. RIP was 96, and PIP was 83. The positive predictive values were 92.9%, 64%, and 68% respectively. In the control group of 171 patients, the PIS was validated in 160 patients who would not experience dislocations. RIP was 117, and PIP was 50. The negative predictive values were 85.1%, 60.9%, and 36.2%, respectively. The area under the curve score for the PIS was 0.866, and the RIP was 0.673. the PIP was 0.678.ConclusionRIP and PIP did not work to predict LPD. PIS can accurately predict recurrent lateral patellar dislocation. It can aid doctors in making treatment decisions.Level of evidenceLevel III, retrospective comparative study.

The aim of this study was to evaluate the efficacy of a new minimally invasive surgical technique for the reconstruction of the medial patellofemoral ligament (MPFL) with fascia lata allograft at 60-month minimum follow-up. Nineteen consecutive patients with chronic recurrent patellar dislocation were treated with MPFL reconstruction (53% isolate procedure, 47% in combination with other treatments). Seventeen patients (11 males/6 females) were available at 60-month follow-up and were clinically evaluated with validated scores. New episodes of patellar dislocation were considered failures. Radiographic and CT scan evaluation were executed preoperatively and at 60-month follow-up. All clinical scores improved from preoperative assessment to 24-month and 60-month follow-up (p < 0.001). Kujala score increased from 61.2 ± 18.1 to 86.7 ± 8.7 and 82.1 ± 10.2; KOOS increased from 54.5 ± 19 to 86.8 ± 9.6 and 84.3 ± 7.6; VAS for pain decreased from 5.1 ± 2.2 to 2.4 ± 1.5 and 1.7 ± 1.2; Tegner score increased from 3 [2-4] to 5 [3-8] and 5 [3-9], respectively. Objective IKDC improved too. No significant improvements between the 24-month and 60-month follow-up evaluations were recorded. Anterior knee pain was reported in two patients (12%). Treatment failure, a new episode of patellar dislocation 25months after the surgery, was observed in one patient (6%). Radiographic OA changes were not statistically significant between preop and 60-month follow-up. Tuberosity-troclear groove (TT-TG) distance and the patellar tilt angle were subjected to significant changes due to MPFL reconstruction and associated procedures. MPFL reconstruction with fascia lata allograft, alone or combined with other procedures, is a reliable treatment option for recurrent patellar dislocation with a success rate of 94% and without cartilage deterioration at 60-month follow-up. IV.

Hybrid Medial Patellofemoral Ligament Reconstruction Using the Semitendinous Tendon for Recurrent Patellar Dislocation: Minimum 3 Years’ Follow-up

Background The medial patellofemoral ligament (MPFL) is the main static patellar stabilizer beyond 30° of knee flexion. Nowadays, MPFL reconstruction is the gold standard operation for recurrent patellar dislocation. Aim To assess the results of double-bundle transpatellar MPFL reconstruction using semitendinosus graft. A case series study held at Alexandria University Hospitals. Patients and methods Between May 2011 through October 2013, 58 patients with recurrent patellar dislocation were treated by MPFL reconstruction using semitendinosus tendon autograft. Their mean age was 20.05 years. There were 13 men and 45 women. All patients were followed up for at least 24 months. Patients were assessed using the Kujala score. Results The overall results were considered good to excellent. No case reported postoperative redislocation. All patients had negative apprehension test postoperatively. The mean Kujala score improved from preoperative 49 (range: 35–64) points to postoperative 93.9 (P Conclusion The use of transpatellar technique for MPFL reconstruction has very low complication rate of more than 24 months follow-up. There were no reported cases of patellar fractures or loss of knee flexion.