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.

Two-type classification system for femoral trochlear dysplasia in recurrent patellar instability based on three-dimensional morphology.

PURPOSE: Radiographic and two-dimensional (2D) CT/MRI analysis of femoral trochlear dysplasia play a significant role in surgical decision-making for recurrent patellar instability. However, the three-dimensional morphology of dysplastic trochlea is rarely studied due to the limitations of conventional imaging modalities. This study aimed to (1) develop a 3D morphological classification for trochlear dysplasia based on the concavity of the trochlear groove and (2) analyze the interrater reliability of the classification system. METHODS: The 3D trochleae of 132 knees with trochlear dysplasia and recurrent patellar instability were reconstructed using CT scan data and classified using the innovative classification criteria between January 2016 and June 2020. A concave trochlear sulcus with sloped medial and lateral trochlear facets was classified as Type I trochlea. The trochlear groove with no concavity is classified as Type II. Furthermore, in Type II, the trochlea with the elevated trochlear floor at the proximal part was identified as IIa and the trochlea with the hypoplastic trochlear facets as IIb. The intra- and inter-rater reliability was examined using kappa (κ) statistics. RESULTS: The 3D classification system showed substantial intra-rater agreement and moderate interrater agreement (0.581 ~ 0.772). The intra- and interrater agreement of Dejour's four-grade classification was fair-to-moderate (0.332 ~ 0.633). Eighty-one trochleae with concave trochlear sulcus were classified as Type I, and fifty-one without concavity as Type II. Twenty-five non-concave trochleae were classified as type IIa due to the elevated trochlear floor and 26 trochleae into IIb with the hypoplasia of trochlear facets. CONCLUSION: This study developed a 3D classification system to classify trochlear dysplasia according to trochlear concavity and morphology of the trochlear facets. On CT/MRI scans or 3D reconstructions, the interpretation of features of dysplastic trochleae may vary, especially for the flat and convex trochleae. The novel system provides morphological evidence for when to consider trochleoplasty according to the different types of trochlear sulcus.

Medial Patellofemoral Ligament Reconstruction: An Uncommon Solution for a Common Problem.

Patellofemoral dislocations are commonly encountered knee ailment. Although majority of the patients are managed conservatively, depending on the patients' demands and predisposing factors, patients with recurrent dislocations often require surgical intervention. The main aim of any surgical procedure should be to restore the anatomy of the soft tissue as well as the bony elements. We here describe a technique which combines transverse patella double tunnel technique with tibial tuberosity distalization and medicalization to reconstruct the medial patellofemoral ligament using a free autologous semitendinosus graft.

Medialization of trochlear groove was correlated with extended lateral trochlear in trochlear dysplasia: a transverse CT analysis.

PURPOSE: To investigate the difference of trochlear width between normal and dysplastic trochlear and to analyze whether the medialization of trochlear groove was correlated with abnormal width of trochlear facets in trochlear dysplasia. METHODS: This study involved CT scans of fifty knees with trochlear dysplasia (TD group) and fifty knees without obvious trochlear dysplasia (Normal group). The linear distance from the medial femoral epicondyle to the various reference points was measured on axial CT images which included the medial edge of medial trochlear facet (dMTE), trochlear groove (dTG), and the lateral edge of lateral trochlear facets (dLTE). The medial and lateral trochlear width was calculated and standardized by the width of the anatomical epicondylar axis. Pearson's correlation analysis was performed between the dTG and the width of the medial and lateral trochlear. RESULTS: The reliability of the results was good. Intraclass correlation coefficient (ICC) ranged from 0.89 to 0.97. The dMTE was significantly greater in the TD group than the normal group (32.7 ± 5.1% vs. 29.6 ± 3.5%, p = 0.009). There was no significant difference in the dLTE between groups. The dTG was reduced in the TD group compared with the normal group (45.2 ± 4.1% vs. 49.1 ± 3.9%, p = 0.019). In the TD group, there was a significant reduction in the medial trochlear width (13.9 ± 4.1% vs. 19.4 ± 2.9%, p < 0.001) and a significant increase in the lateral trochlear width (31.3 ± 4.0% vs. 26.9 ± 3.6%, p < 0.001) compared with the normal group. The dTG was significantly correlated with the lateral trochlear width (r value = - 0.693, p < 0.001) and not correlated with the medial trochlear width (r value = 0.044, p = 0.766) in trochlear dysplasia. CONCLUSIONS: This study demonstrated that dysplasia of trochlear morphology was related to the reduction of medial trochlear width and increase in lateral trochlear width. The medialization of trochlear groove was significantly correlated with the increased lateral trochlear width.

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.

Clinical outcomes and predictive factors for failure with MPFL reconstruction combined with tibial tubercle osteotomy and lateral retinacular release for recurrent patellar instability.

BACKGROUND: Medial patellofemoral ligament (MPFL) reconstruction combined with tibial tubercle osteotomy (TTO) and lateral retinacular release (LRR) is one of the main treatment methods for patellar instability. So far, few studies have evaluated the clinical effectiveness and assessed potential risk factors for recurrent patellar instability. PURPOSE: To report the clinical outcomes of MPFL reconstruction combined with TTO and LRR at least three years after operation and to identify potential risk factors for recurrent patellar instability. METHODS: A retrospective analysis of medical records for patients treated with MPFL, TTO and LRR from 2013 to 2017 was performed. Preoperative assessment for imaging examination included trochlear dysplasia according to Dejour classification, patella alta with the Caton-Deschamps index (CDI), tibial tubercle-trochlear groove distance. Postoperative assessment for knee function included Kujala, IKDC and Tegner scores. Failure rate which was defined by a postoperative dislocation was also reported. RESULTS: A total of 108 knees in 98 patients were included in the study. The mean age at operation was 19.2 ± 6.1 years (range, 13-40 years), and the mean follow-up was 61.3 ± 15.4 months (range, 36-92 months). All patients included had trochlear dysplasia (A, 24%; B, 17%; C, 35%; D, 24%), and 67% had patellar alta. The mean postoperative scores of Tegner, Kujala and IKDC were 5.3 ± 1.3 (2-8), 90.5 ± 15.5 (24-100) and 72.7 ± 12.1 (26-86). Postoperative dislocation happened in 6 patients (5.6%). Female gender was a risk factor for lower IKDC (70.7 vs 78.1, P = 0.006), Tegner (5.1 vs 6.0, P = 0.006) and Kujala (88.2 vs 96.6, P = 0.008). Age (p = 0.011) and trochlear dysplasia (p = 0.016) were considered to be two failure factors for MPFL combined with TTO and LRR. CONCLUSION: As a surgical method, MPFL combined with TTO and LRR would be a reliable choice with a low failure rate (5.6%). Female gender was a risk factor for worse postoperative outcomes. Preoperative failure risk factors in this study were age and trochlear dysplasia. LEVEL OF EVIDENCE: Level IV; Case series.

Outcomes of MPFL reconstruction with tibial tubercle transfer for recurrent patellar instability with high grade trochlear dysplasia in Indian population.

BACKGROUND: Patellar instability is a painful condition which affects the quality of life and mobility of young individuals. The aim of this study is to observe the results of medial patello-femoral ligament reconstruction with hamstring autograft along with a modified Fulkerson osteotomy, for recurrent instability of patella with high-grade trochlear dysplasia in Indian population. MATERIALS & METHODS: We conducted a prospective observational study of 26 knees (21 patients) who attended our outpatient department from June 2014 to February 2019, with recurrent instability of the patella and high-grade trochlear dysplasia. All knees were treated with MPFL reconstruction with hamstring autograft and modified Fulkerson osteotomy. RESULTS: The mean follow-up period was 30 months (range: 24-50). The mean Lysholm scores improved from 49.9 (range: 30-63) preoperatively to 82.5 (range: 51-100) (p < 0.05), Kujala scores from 55.5 (36-67) to 85.9 (55-100) and International Knee Documentation Committee (IKDC) scores from 50.2 (31.6-62.3) to 82.9 (54.7-98.3) (p < 0.05) at 2 years follow-up. TT-TG distance decreased from 21.2 mm (18-25) to 11.6 mm (10-13) (p < 0.05) and patellar tilt angle decreased from 24.2° (18°-35°) to 7.2° (5°-10°) (p < 0.05). One knee had superficial skin infection in immediate post-operative period. Three knees had postoperative stiffness, which improved on manipulation under anesthesia. Six knees had implant irritation from the osteotomy screws which were removed after bony union was achieved. Functional scores were low in two knees due to patello-femoral pain, but they did not have recurrent instability. CONCLUSION: MPFL reconstruction with tibial tubercle transfer gives good functional outcomes in 92.3% patients with recurrent patellar instability, associated with high-grade trochlear dysplasia in Indian population.

Isolated reconstruction of medial patellofemoral ligament with an elastic femoral fixation leads to excellent clinical results.

PURPOSE: The primary objective was to compare the functional outcomes after an isolated MPFL reconstruction using either a quasi-anatomical technique (group A) or an anatomical MPFL reconstruction (group B). The secondary objectives were to compare the rates of redislocation, range-of-motion and subjective patellar instability (Smillie test). METHODS: A multicenter longitudinal prospective comparative study was performed. Group A had 29 patients and 28 were included in Group B. Patients with trochlear dysplasia types C and D and patients who had undergone a trochleoplasty, a distal realignment or patella distalization concurrently with MPFL reconstruction were excluded. The main evaluation criterion was the Kujala functional score. RESULTS: The mean postoperative Kujala was 90.4 (89.4 in group A and 92.1 in group B). Upon comparing the mean difference between pre- and post-operative values, no differences were detected between the two groups (n.s). CONCLUSIONS: Isolated quasi-anatomical MPFL reconstruction using a gracilis tendon autograft for recurrent patellar dislocation provides outcomes as good as the isolated anatomical MPFL reconstruction in patients with no trochlear dysplasia up to those with trochlear dysplasia type A and B at the 2-5 years follow-up. LEVEL OF EVIDENCE: Level IV.

Increased femoral anteversion is associated with inferior clinical outcomes after MPFL reconstruction and combined tibial tubercle osteotomy for the treatment of recurrent patellar instability.

PURPOSE: This study aimed at investigating the influence of an increased femoral anteversion angle on clinical outcomes after medial patellofemoral ligament reconstruction and combined tibial tubercle osteotomy for the treatment of recurrent patellar instability. It was hypothesized that an increased femoral anteversion is associated with inferior clinical outcomes. METHODS: From 2014 to 2016, a total of 144 consecutive patients with recurrent patellar instability were treated with medial patellofemoral ligament reconstruction and combined tibial tubercle osteotomy. The femoral anteversion angle was measured using three-dimensional computed tomography scans. Patients were allocated into group A (femoral anteversion < 20°), group B (femoral anteversion 20°-30°) and group C (femoral anteversion > 30°) based on the value of the femoral anteversion angle. Routine radiography and CT examinations were performed to evaluate the patellar height, trochlear dysplasia, genu valgum, and tibial tuberosity-trochlear groove (TT-TG) distance. The patellar lateral shift distance assessed with stress radiography was used pre- and postoperatively to quantify medial patellofemoral ligament residual laxity under anaesthesia. Patient-reported outcomes (Kujala, IKDC, and Lysholm scores) and patellar maltracking ("J-sign") were evaluated pre- and postoperatively. Finally, subgroup analysis was performed to investigate the influence of an increased femoral anteversion angle on the clinical and radiological outcomes. RESULTS: A total of 66 patients (70 knees) were included with a median follow-up time of 28 months (range 24-32). After a minimum of 2 years of follow-up, all patient-reported outcomes (Kujala, Lysholm, and IKDC scores) improved significantly, and subgroup analysis showed that group C had significantly lower Kujala scores (75 ± 8 vs. 84 ± 8, P13 = 0.003; 75 ± 8 vs. 82 ± 8, P23 = 0.030), Lysholm scores (81 ± 9 vs. 87 ± 7, P13 = 0.021) and IKDC scores (78 ± 6 vs. 85 ± 7, P13 = 0.001; 78 ± 6 vs. 84 ± 6, P23 = 0.005) than group A and group B. Twelve patients had a postoperative residual J-sign (17.1%), and significant differences were found between group C and group A regarding the rate of residual J-sign (32.1% vs. 4.8%, P13 = 0.003). Postoperatively, group C had a greater patellar lateral shift distance than group A (10 ± 4 vs. 6 ± 4 mm, P13 = 0.006) and group B (10 ± 4 vs. 6 ± 3 mm, P23 = 0.008). Additionally, patients with a residual J-sign demonstrated greater medial patellofemoral ligament laxity than patients without a residual J-sign (12 ± 4 vs. 9 ± 3 mm, P = 0.009). CONCLUSION: Patients with an increased femoral anteversion angle (> 30°) had inferior postoperative clinical outcomes, including greater patellar laxity, a higher rate of residual J-sign and lower patient-reported outcomes after medial patellofemoral ligament reconstruction and combined tibial tubercle osteotomy for the treatment of recurrent patellar instability. LEVEL OF EVIDENCE: III, retrospective cohort study.

Avoiding Complications with MPFL Reconstruction.

PURPOSE OF REVIEW: To discuss the potentially significant complications associated with medial patellofemoral ligament (MPFL) reconstruction. Additionally, to review the most current and relevant literature with an emphasis on avoiding these potential complications. RECENT FINDINGS: Multiple cadaveric studies have characterized the anatomy of the MPFL and the related morphologic abnormalities that contribute to recurrent lateral patellar instability. Such abnormalities include patella alta, excessive tibial tubercle to trochlear grove (TT-TG) distance, trochlear dysplasia, and malalignment. Recent studies have evaluated the clinical outcomes associated with the treatment of concomitant pathology in combination with MPFL reconstruction, which is critical in avoiding recurrent instability and complications. Although there remains a lack of consensus regarding various critical aspects of MPFL reconstruction, certain concepts remain imperative. Our preferred methods and rationales for surgical techniques are described. These include appropriate work up, a combination of procedures to address abnormal morphology, anatomical femoral insertion, safe and secure patellar fixation, appropriate graft length fixation, and thoughtful knee flexion during fixation.

Patellar tracking should be taken into account when measuring radiographic parameters for recurrent patellar instability.

PURPOSE: To date, many radiographic parameters on patellar instability have their measurements taken statically, and have not been studied in various degrees of flexion according to the patellar tracking. There are also limited data regarding the use of these parameters in predicting recurrent patellar dislocation. The current study aims to review the radiographic parameters of the patellofemoral joint in different degrees of knee flexion and to correlate them with the presence of recurrent instability. METHODS: A 10-year retrospective study was conducted on all patients who had computed tomography patellar-tracking scan done for patellar instability when aged 18 years or younger. The computed tomography patellar-tracking scans were performed with the knee in extension, 10° flexion, and 20° flexion. The axial radiographic parameters were evaluated at the patellar equator, roman arch, and distal patellar pole. Sagittal and coronal parameters were noted. Radiographic parameters were then correlated with recurrent patellar instability. RESULTS: The femoral sulcus angle and trochlear groove depth at the distal patellar pole in 10° knee flexion (p value 0.04 and 0.03, respectively) and patellar equator in 20° knee flexion (p value 0.02 and 0.03, respectively) had the most significant clinical correlations with recurrent instability on multivariate analysis. Other radiographic parameters found to have significant clinical correlation on univariate analysis include the patellar tilt angle, congruence angle, femoral sulcus angle, trochlear groove depth, and Wiberg's classification. CONCLUSIONS: As per the knee dynamics, axial radiographic parameters had the most significant correlation with recurrent patellar instability when measured at the distal patellar pole in 10° knee flexion and at the patellar equator in 20° knee flexion. Future axial radiographic evaluation of patellofemoral instability should then be performed at these degrees of knee flexion and axial cuts. Trochlear dysplasia, as measured by the femoral sulcus angle and trochlear groove depth, was the most significant predictor of recurrent patellar instability in the skeletally immature. Wiberg's classification was also a novel factor found to have clinical correlation with patellofemoral instability. LEVEL OF EVIDENCE: III.

Results of operative 4-in-1 patella realignment in children with recurrent patella instability.

PURPOSE: Recurrent patellar instability is a cause of knee dysfunction, limitation and pain for children. If nonoperative treatment fails to stabilise the patella, operative realignment and stabilisation have been advocated. Operative techniques in the paediatric population must preserve physeal growth while ensuring stability. We aimed to determine the outcome of children and adolescents who underwent a 4-in-1 patellar realignment (lateral release, medial reefing, Insall tube realignment and Roux-Goldthwaite patella ligament transfer). METHODS: Consecutive skeletally immature patients operated in our institution were included in the study. A total of 16 operated knees in 12 patients were recruited. All patients underwent the same procedure after attempting a minimum period of 6 months of non-operative treatment with unsatisfactory results. The main outcome measured was recurrent dislocations. Functional outcomes were assessed using the Kujala score and the Paediatric form of the International Knee Documentation Committee Subjective Knee Form (Pedi-IKDC). RESULTS: Patients were followed up for a minimum of 3 years. None of the patients sustained further patella dislocations following the operation. In 3 cases, minor patellar maltracking was noted post-operatively but all 3 remained asymptomatic. Three patients had a small area of numbness lateral to the operative incision, which coincided with hypertrophic scarring. There was one case of superficial wound infection. The mean Kujala score was 83.4 ± 11.47 and the mean Pedi-IKDC was 79.5 ± 12.56 at the latest follow-up (minimum of 36 months). CONCLUSIONS: The 4-in-1 patellar realignment is a good procedure in paediatric and adolescent patients with recurrent patella instability. Satisfactory results were observed with a minimal complication and redislocation rate in our series.

Medial patella-femoral ligament reconstruction using the anterior half of the peroneus longus tendon as a combined procedure for recurrent patellar instability.

BACKGROUND: Medial patella-femoral ligament reconstruction (MPFLR) using hamstring tendon is the main procedure for recurrent patellar instability. The anterior half of the peroneus longus tendon (AHPLT) has been proven to be a useful alternate to the hamstring tendon in knee ligament reconstruction. The purpose of this study was to evaluate the clinical outcome of MPFLR using the new graft. METHODS: Forty-five patients with recurrent patellar instability received MPFLR using the AHPLT. Tibial tubercle transfer and lateral release were also performed. Follow-ups were performed at 12 months and 24 months postoperatively, and computed tomography was performed immediately following the operation and at follow-up. The passive patella glide test was performed prior to surgery, during the operation, and at each follow-up point. Knee function was evaluated preoperatively and postoperatively using the International Knee Documentation Committee, Lysholm, Kujala, and Tegner rating scales. RESULTS: Forty patients were followed for 2 years and received complete serial computed tomography examinations and functional evaluations. The correction of the static patellar position remained through the follow-ups. Functional evaluations at 2 years revealed statistical significant improvement over preoperative status, with International Knee Documentation Committee subjective score, Lysholm score, Kujala score, and Tegner score. CONCLUSION: AHPLT is a promising alternative graft for MPFLR, together with lateral release and tibial tubercle transfer, satisfactory static patellar position, and functional outcomes have been achieved in the treatment of recurrent patellar dislocation in adults. LEVEL OF EVIDENCE: Level IV, case series.

Dynamic medial patellofemoral ligament reconstruction in recurrent patellar instability: A surgical technique.

The medial patellofemoral ligament (MPFL) is the primary stabilizer of the patellofemoral joint; its reconstruction has been recommended in adults over the past decade after recurrent patellar instability. However, there has been no standardized technique for reconstruction, therefore, ideal graft and technique for reconstruction are yet undetermined. However, dynamic MPFL reconstruction studies claim to be superior to other procedures as it is more anatomical. This preliminary study aims at assessing the outcomes of MPFL reconstruction in a dynamic pattern using hamstring graft. We performed this procedure in four consecutive patients with chronic patellar instability following trauma. MPFL reconstruction was done with hamstring tendons detached distally and secured to patellar periosteum after being passed through a bony tunnel in the patella without an implant and using the medial collateral ligament as a pulley. In all 4 knees, the MPFL reconstruction was isolated and was not associated with any other realignment procedures. No recurrent episodes of dislocation or subluxation were reported at 24 months followup.

Tratamiento quirúrgico de la inestabilidad rotuliana recurrente con reconstrucción del ligamento patelofemoral medial usando autoinjerto semitendinoso / Surgical treatment of recurrent patellar instability with medial patellofemoral ligament reconstruction using semitendinosus tendon autograft

The medial patellofemoral ligament (MPFL) reconstruction is an option for the recurrent patellar instability. We developed a prospective study whose objective was to show the functional results at 6 and 12 months of patients who underwent MPFL reconstruction with semitendinosus (St) autograft. Four patients (5 knees) were treated between May 2006 and May 2008. The Kujala´s test before surgery in all patients was poor (< 50 points); 6 months after the surgery 4 cases turned out to be "good and very good" (only 1 case "poor", but increased her score to 78 points) and after 12 months of follow-up, 5 cases scored "very good and excellent" (score > 90 points). The Tegner´s test showed an increased of activity that was normal for the patients, and with the Insall´s test all patients referred very satisfied 12 months after surgery. Up to this stage, there has been no recurrence. In our local environment, the MPFL reconstruction with St. is a valid treatment to recover the patellofemoral mecanic.

La reconstrucción del ligamento patelofemoral medial (LPFM) es una alternativa en la inestabilidad rotuliana recurrente. Desarrollamos un estudio prospectivo con el objetivo de exponer los resultados funcionales a los 6 y 12 meses de pacientes sometidos a una reconstrucción del LPFM con semitendinoso (St). Son 4 pacientes (5 rodillas) operados entre mayo 2006 y mayo 2008. El test de kujala preoperatorio era "malo" (< 50 pts) en todos, a los 6 meses post op. 4 casos de "bueno y muy bueno" resultado (sólo 1 caso "malo", pero con incremento de su score a 78) y a los 12 meses (5 casos) todos con función "muy bueno y excelente" (score > 90 pts). El test de Tegner mostró un aumento del nivel de actividad considerada de normal en todos los pacientes, y en el test de Insall todos refieren excelente mejoría a los 12 meses. Hasta la fecha no existen recidivas. En nuestro medio local, la reconstrucción del LPFM con St. es una alternativa válida para recuperar la mecánica patelofemoral.

Results of Recurrent Patellar Instability after Trauma According to Anatomical Predisposing Factors

PURPOSE: We analyzed the results of lateral retinacular release(LRR) and proximal realignment for recurrent patellar instability after trauma according to the anatomical predisposing factors. MATERIALS AND METHODS: Twelve patients of fifteen cases of recurrent patellar instability had been evaluated. Clinical assessment were performed by Q-angle, apprehension test, passive patellar tilt test and general joint laxity. The anatomical predisposing factors assessed by plain radiographs included patella alta, sulcus angle, femoral trochlear dysplasia, genu valgum and patellar dysplasia. Clinical results were assessed by Kujala scoring system. Radiographic results were assessed by congruence angle. The results were analyzed according to the predisposing factors. RESULTS: Patella alta was observed in eight, increased sulcus angle in six, trochlear dysplasia in twelve, genu valgum in five and patella dysplasia in four cases. The result of treatment (Kujala score / congruence angle) was 85.8 / 9.7degrees in group A(predisposing factors > or = 3) and 91.4 / -5.3degrees in group B (predisposing factors<3)(p=0.036). We had 4 cases of recurrence after operation and genu valgum was related with recurrence rate. CONCLUSION: The clinical results of LRR and proximal realignment for recurrent patellar instability developed after trauma were worse in cases with more anatomical predisposing factors.