Use of a modified Elmslie-Trillat procedure to improve abnormal patellar congruence angle

Patellar tilt, congruence angle, and tibial tubercle-trochlear groove distance are correlated with positive J-sign in adolescents

PURPOSE

The J-sign is a clinical evaluation tool that assesses for patellar maltracking and is considered positive if lateral translation of the patella in extension, in the pattern of an inverted J is observed. This study aims to determine the association of clinical J-sign with imaging features noted on dynamic kinematic computed tomography (DKCT).

METHODS

A retrospective review was conducted by reviewing the clinical records of all patients aged 18 years or younger who had a CT patellar tracking scan done between 1 January 2005 to 31 December 2016 in a single institution. Patients who had the presence or absence of a 'J-sign' evaluated clinically were included. Radiographic parameters evaluated using the axial cuts include the patellar tilt angle, congruence angle, Dejour's classification, femoral sulcus angle, trochlear groove depth, and Wiberg's classification. Patients were then divided into two groups based on the presence or absence of J-sign on clinical examination. The radiographic measurements were then analyzed for association with the presence or absence of J-sign on clinical examination.

RESULTS

Patients with a positive J-sign had an increased patellar tilt of 23.3° ± 14.2° and an increased congruence angle of 47.1° ± 28.5° when measured in extension as compared to a patellar tilt of 18.3° ± 10.8° and a congruence angle of 32.1° ± 20.8° in patients with a negative J-sign (p = 0.024 and 0.004, respectively). Comparisons of the change in congruence angles with the knee in full extension and at 20° flexion also yielded significantly higher change of 28.0° ± 20.4° in patients with a positive J-sign as compared to 11.9° ± 17.5° in patients with a negative J-sign. Patients with a positive J-sign also had an increased TT-TG distance of 17.6 ± 5.6 mm as compared to a TT-TG distance of 14.7 ± 6.9 mm in patients with a negative J-sign (p = 0.01).

CONCLUSION

Patients with a positive J-sign had an increased patellar tilt and an increased congruence angle when measured in extension. Increased TT-TG distance was also significantly associated with positive J-sign. Patients with a positive J-sign also had a greater change in their congruence angle when measured with the knee in full extension and at 20° of flexion.

Incidence of Complications After Tibial Tubercle Osteotomy and Tibial Tubercle Osteotomy With Distalization

BACKGROUND

Tibial tubercle osteotomy (TTO) is a well-established surgical treatment option for patellofemoral instability and pain. TTO with distalization (TTO-D) is indicated for patients with patellofemoral instability, patellar malalignment, and patella alta. The current literature demonstrates several complications that may be associated with TTO, with reportedly higher rates of complications associated with TTO-D.

PURPOSE

To analyze and compare complication rates after TTO without distalization (TTO-ND) and TTO-D and assess risk factors associated with complications.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

All skeletally mature patients who underwent TTO with or without distalization by a single surgeon between September 2014 and May 2023 with a minimum of 6 months of clinical follow-up were retrospectively reviewed. Patient factors, surgical indications, perioperative data, and complications were collected via a retrospective review of electronic medical records. Concomitant procedures were categorized as intra-articular, extra-articular, and osteotomies.

RESULTS

A total of 251 TTOs (117 TTO-D, 134 TTO-ND) were included in the study group. Postoperative complications were observed in 15 operations (6%), with arthrofibrosis as the most common complication (10 operations [4%]). TTO-D and TTO-ND had similar rates of complication (5% vs 7%; P = .793). Clinical nonunion was observed in 3 operations (3%) in the TTO-D cohort and 1 operation (1%) in the TTO-ND cohort. In the TTO-D cohort, concomitant intra-articular procedures were significantly associated with an increased likelihood of complications in a univariate model. In the TTO-ND cohort, an increased tourniquet time was significantly associated with an increased likelihood of complications in a univariate model. For all TTOs as well as the TTO-D and TTO-ND cohorts, there were no significant associations between patient or surgical variables in a multivariate model.

CONCLUSION

TTO with and without distalization is a safe procedure with low rates of complication. TTO-D was not associated with a higher rate of complications compared with TTO-ND. There was no association between complications and surgical variables for TTO procedures.

Comparison of four different screw configurations for the fixation of Fulkerson osteotomy: a finite element analysis

BACKGROUND

Conventionally, two 4.5 mm cortical screws inserted toward the posterior tibial cortex are usually advocated for the fixation of Fulkerson osteotomy. This finite element analysis aimed to compare the biomechanical behavior of four different screw configurations to fix the Fulkerson osteotomy.

MATERIALS AND METHODS

Fulkerson osteotomy was modeled using computerized tomography (CT) data of a patient with patellofemoral instability and fixed with four different screw configurations using two 4.5 mm cortical screws in the axial plane. The configurations were as follows: (1) two screws perpendicular to the osteotomy plane, (2) two screws perpendicular to the posterior cortex of the tibia, (3) the upper screw perpendicular to the osteotomy plane, but the lower screw is perpendicular to the posterior cortex of the tibia, and (4) the reverse position of the screw configuration in the third scenario. Gap formation, sliding, displacement, frictional stress, and deformation of the components were calculated and reported.

RESULTS

The osteotomy fragment moved superiorly after loading the models with 1654 N patellar tendon traction force. Since the proximal cut is sloped (bevel-cut osteotomy), the osteotomy fragment slid and rested on the upper tibial surface. Afterward, the upper surface of the osteotomy fragment acted as a fulcrum, and the distal part of the fragment began to separate from the tibia while the screws resisted the displacement. The resultant total displacement was 0.319 mm, 0.307 mm, 0.333 mm, and 0.245 mm from the first scenario to the fourth scenario, respectively. The minimum displacement was detected in the fourth scenario (upper screw perpendicular to the osteotomy plane and lower screw perpendicular to the posterior tibial cortex). Maximum frictional stress and maximum pressure between components on both surfaces were highest in the first scenario (both screws perpendicular to the osteotomy plane).

CONCLUSIONS

A divergent screw configuration in which the upper screw is inserted perpendicular to the osteotomy plane and the lower screw is inserted perpendicular to the posterior tibial cortex might be a better option for the fixation of Fulkerson osteotomy. Level of evidence Level V, mechanism-based reasoning.

How to fix a tibial tubercle osteotomy with distalisation: A finite element analysis

BACKGROUND

Antero-medialisation osteotomy combined with a distalisation procedure may require a more stable fixation as the osteotomy fragment loses both proximal and distal support. This finite element analysis aimed to compare the mechanical behaviour of different fixation techniques in tibial tubercle antero-medialisation osteotomy combined with distalisation procedure.

METHODS

Tibial tubercle osteotomy combined with distalisation was modelled based on computerised tomography data, which were acquired from a patient with patellar instability requiring this procedure. Six different fixation configurations with two 3.5-mm cortical screws (1), two 4.5-mm cortical screws (2), three 3.5-mm cortical screws (3), three 4.5-mm cortical screws (4), three 3.5-mm screws with 1/3 tubular plate (5), and four 3.5-mm screws with 1/3 tubular plate (6) were created. A total of 1654 N of force was applied to the patellar tendon footprint on the tibial tubercle. Sliding, gap formation, and total deformation between the osteotomy components were analyzed.

RESULTS

Maximum sliding (0.660 mm), gap formation (0.661 mm), and displacement (1.267 mm) were seen with two 3.5-mm screw fixation, followed by two 4.5-mm screws, three 3.5-mm screws, and three 4.5-mm screws, respectively, in the screw-only group. Overall, the minimum displacement was observed with the four 3.5-mm screws with 1/3 tubular plate fixation model.

CONCLUSIONS

Plate fixation might be recommended for tibial tubercle antero-medialisation osteotomy combined with distalisation procedure because it might allow early active range of motion exercises and weight-bearing.

Older age and varus alignment lead to early failure in treating patellofemoral osteoarthritis with Fulkerson osteotomy

Background: It is unclear the risk factors for the failure of modified Fulkerson osteotomy. Methods: We retrospectively reviewed 40 patients who underwent the modified Fulkerson osteotomy from 1998 to 2015. There were 4 males and 36 females. The mean age of the study group was 50.2 ± 11.2 years. We used standard anteriorization measuring 10-15 mm and medialization measuring 10 mm while maintaining an intact periosteal sleeve. Results: Both the patellofemoral angle and the congruence angle improved significantly after 5.9 years. Preoperatively, the mean preoperative Lysholm score was 56.12, and the Knee Society score was 60.52. At the final follow-up, these scores improved significantly to 88.75 and 86.49, respectively. However, eight patients (20%) underwent total knee arthroplasty in the follow-up period, five of whom underwent the operation within 5 years. Comparing the survival and non-survival groups, there was a significant difference of an older age in the TKA conversion group (survival: 48.3 ± 11.1; non-survival: 57.8 ± 8.7, p = 0.03). For knee alignment, the non-survival group had a mean valgus femorotibial angle of 1.8° ± 4.9° preoperatively, and the survival group had a mean valgus angle of 6.4° ± 4.5° (p = 0.03). Conclusions: we found that patients with older age and those with varus alignment have an increased risk of deteriorated medial femorotibial cartilage.

Patellofemoral Arthroplasty Surgical Technique: Lateral or Medial Parapatellar Approach

BACKGROUND

Patellofemoral arthroplasty (PFA) is an emerging treatment for patients with isolated patellofemoral compartment osteoarthritis. The medial parapatellar approach is the standard arthrotomy but has been shown in total knee arthroplasty to damage the patellar blood supply and increase postoperative patellar instability. The lateral parapatellar approach is an alternative that may reduce the risk of these outcomes. The purpose of this study is to compare the radiographic measures of patellar tracking and patient-reported outcomes of the medial and lateral parapatellar approaches in PFA.

METHODS

Between 2012 and 2019, a retrospective review was performed of 136 knees undergoing PFA at a single institution. Patients were separated by preoperative congruence angle and then surgical approach into 3 cohorts. Preoperative and postoperative patellar tilt and congruence angle were measured. Preoperative and minimum 6-month postoperative patient-reported outcomes scores were collected.

RESULTS

There were no significant differences in the mean postoperative congruence angle and postoperative patient-reported outcomes among the 3 cohorts. Mean postoperative patellar tilt was normalized only in the abnormal congruence angle/lateral approach group to 2.80° (standard error, 1.85).

CONCLUSION

Congruence angle was improved regardless of surgical approach. Patellar tilt was normalized only for the lateral approach in patients with abnormal preoperative congruence angle. There were no significant differences in preoperative and postoperative scores between groups except for preoperative 12-item Short Form Mental Health Survey scores. This study supports that the lateral approach offers improved postoperative patellar tilt compared to a medial approach for PFA while achieving similar patient-reported outcomes.

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.

The Evolution of Patellofemoral Instability Surgery During the Past 25 Years

Surgical treatment of patellofemoral instability has evolved during the past 25 years as we developed a better appreciation of anatomy and a more sophisticated understanding of pathophysiology. Currently, most patellofemoral surgeons use soft tissue procedures like medial patellofemoral ligament reconstruction to treat medial soft tissue insufficiency and tibial tuberosity or femoral osteotomy to correct substantial bony malalignment. Advances in imaging technology and computational analysis have allowed for more precise preoperative planning and outcome modeling so that the optimum operation using ≥1 of these procedures can be designed to meet the unique needs of an individual patient.

Complications After Tibial Tuberosity Osteotomy: Association With Screw Size and Concomitant Distalization

Background:

Tibial tuberosity osteotomy (TTO) is a versatile procedure commonly used to treat patellar instability as well as to unload cartilage lesions. TTO with concomitant distalization (TTO-d) may be performed in patients with patella alta to stabilize the patella by helping it to engage in the trochlea earlier during flexion.

Purpose:

To identify and compare perioperative complications in patients who underwent TTO and those who underwent TTO-d and to analyze risk factors associated with these complications.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

We retrospectively identified perioperative complications and associated factors from medical records for 240 patients who underwent TTO with or without distalization performed by 2 surgeons at 2 institutions between 2009 and 2015. A musculoskeletal radiologist at each institution determined osteotomy union using a published grading system. Significance was set at P < .01.

Results:

Of the 240 patients, 153 (122 TTO, 31 TTO-d) had clinical and radiographic follow-up of at least 90 days or evidence of osseous union. Eighty-eight complications were identified in 71 of 153 (46%) patients: delayed union (n = 35); painful hardware (n = 32); deep vein thrombosis (n = 4); clinical nonunion, delayed range of motion, sensory deficit, and wound breakdown (n = 3 each); and broken screw, fascial hernia, hematoma, quadriceps dysfunction, and tibial fracture (n = 1 each). Thirteen of 35 delayed unions occurred in the TTO-d group (P = .005). Painful hardware was more frequent in patients who received 4.5-mm screws (31/115) than in those who received 3.5-mm screws (1/38) (P = .001). A reoperation was required in 38 of 153 patients (37 patients using 4.5-mm screws vs 1 patient using 3.5-mm screws; P < .001), primarily for screw removal (32/38).

Conclusion:

Minor complications, including delayed union and painful hardware, were common, but major complications such as tibial fracture, deep vein thrombosis, and clinical nonunion were rare. Delayed union was more frequent in the TTO-d group. The 3.5-mm screws were less painful and less likely to need removal than the 4.5-mm screws.

Modified Elmslie-Trillat Procedure for Distal Realignment of Patella Tendon

Patellofemoral dysfunction, due to either a patellofemoral malalignment or patellar instability, is a complex and debilitating condition that significantly decreases the knee function. Conservative management may yield significant clinical outcomes; however, when morphologic anomalies are identified, the surgical approach should be employed. Hence, several surgical procedures have been described in the scientific literature aiming the correction of underlying extensor mechanism malalignments. Still, the rate of complications is higher than desirable. The described technique is based on the principles of transferring the tibial tubercle medially as described in the Elmslie-Trillat technique. However, a curvilinear horizontal cut is made prior to the vertical cut, which raises a thick osseous fragment and allows the formation of a gutter when the osseous fragment is moved medially. Whereas the horizontal gutter provides stability to the bone fragment, the thicker dimension of the osseous fragment and retention of the distal attachment significantly enhances the osteotomy union. Hence, adequate pain relief and stability with very low postoperative morbidity could be achieved. The purpose of this surgical note is to describe a modification to the Elmslie-Trillat technique to treat patellofemoral dysfunctions, achieving a higher osseous stability and decreased postoperative morbidity.

Femoral articular geometry and patellofemoral stability

BACKGROUND

Patellofemoral instability is a major cause of anterior knee pain. The aim of this study was to examine how the medial and lateral stability of the patellofemoral joint in the normal knee changes with knee flexion and measure its relationship to differences in femoral trochlear geometry.

METHODS

Twelve fresh-frozen cadaveric knees were used. Five components of the quadriceps and the iliotibial band were loaded physiologically with 175N and 30N, respectively. The force required to displace the patella 10mm laterally and medially at 0°, 20°, 30°, 60° and 90° knee flexion was measured. Patellofemoral contact points at these knee flexion angles were marked. The trochlea cartilage geometry at these flexion angles was visualized by Computed Tomography imaging of the femora in air with no overlying tissue. The sulcus, medial and lateral facet angles were measured. The facet angles were measured relative to the posterior condylar datum.

RESULTS

The lateral facet slope decreased progressively with flexion from 23°±3° (mean±S.D.) at 0° to 17±5° at 90°. While the medial facet angle increased progressively from 8°±8° to 36°±9° between 0° and 90°. Patellar lateral stability varied from 96±22N at 0°, to 77±23N at 20°, then to 101±27N at 90° knee flexion. Medial stability varied from 74±20N at 0° to 170±21N at 90°. There were significant correlations between the sulcus angle and the medial facet angle with medial stability (r=0.78, p<0.0001).

CONCLUSIONS

These results provide objective evidence relating the changes of femoral profile geometry with knee flexion to patellofemoral stability.

Treatment of patellar instability in a case of hereditary onycho-osteodysplasia (nail-patella syndrome) with medial patellofemoral ligament reconstruction: A case report

Hereditary onycho-osteodysplasia, also known as nail-patella syndrome (NPS), is a rare genetic disorder that is primarily characterized by poorly developed nails and patella. Patients with NPS frequently suffer from patellar instability that requires surgical management. The present case report describes a 25-year-old man with NPS. The patient presented with left knee pain and was found to have recurrent left patellar dislocation. The knee pain was first reported 1-year after a minor knee trauma incident. Following complete evaluation, a diagnosis of NPS was reached. The patient underwent surgical intervention using medial patellofemoral ligament (MPFL) reconstruction with a gracilis tendon autograft looped through two transverse 3.2-mm drill holes in the patella and fixed at the natural MPFL insertion site on the medial femoral condyle with an interference screw. The surgery resulted in stabilization of the patella in the femoral trochlea and the patient did not have any subsequent dislocations or subluxations. The patient had an excellent range of knee movement in the follow-up period. This case indicates that MPFL reconstruction in patients with patellar dislocation secondary to NPS can successfully restore normal patellar tracking and result in good range of movement and functional activity.

An Algorithmic Approach to the Management of Recurrent Lateral Patellar Dislocation

High-level evidence supports nonoperative treatment for first-time lateral acute patellar dislocations. Surgical intervention is often indicated for recurrent dislocations. Recurrent instability is often multifactorial and can be the result of a combination of coronal limb malalignment, patella alta, malrotation secondary to internal femoral or external tibial torsion, a dysplastic trochlea, or disrupted and weakened medial soft tissue, including the medial patellofemoral ligament (MPFL) and the vastus medialis obliquus. MPFL reconstruction requires precise graft placement for restoration of anatomy and minimal graft tension. MPFL reconstruction is safe to perform in skeletally immature patients and in revision surgical settings. Distal realignment procedures should be implemented in recurrent instability associated with patella alta, increased tibial tubercle-trochlear groove distances, and lateral and distal patellar chondrosis. Groove-deepening trochleoplasty for Dejour type-B and type-D dysplasia or a lateral elevation or proximal recession trochleoplasty for Dejour type-C dysplasia may be a component of the treatment algorithm; however, clinical outcome data are lacking. In addition, trochleoplasty is technically challenging and has a risk of substantial complications.

The Incidence of Complications of Tibial Tubercle Osteotomy: A Systematic Review

PURPOSE

The goal of this review was to quantify the risk of perioperative and early postoperative complications of tibial tubercle osteotomy (TTO) with different techniques.

METHODS

A systematic review of multiple databases was performed to identify studies that reported complications of TTO. Complications were defined as any adverse outcome, including osteotomy site nonunion, fracture, infection, wound complications, neurovascular complications, deep vein thrombosis (DVT), and pulmonary embolism (PE). Major complications were defined as nonunion, fracture, infections/wound complications requiring return to the operating room, and DVT or PE. The risk of subsequent hardware removal was also quantified.

RESULTS

The 19 identified studies included a total of 787 TTOs: 472 direct medialization procedures (Elmslie-Trillat technique), 193 anteromedialization procedures (Fulkerson technique), and 102 procedures in which the tibial tubercle was completely detached for medialization or distalization, or a combination. The overall complication risk was 4.6%. The risk of complications was higher when the tibial tubercle was completely detached (10.7%) than with Elmslie-Trillat (3.3%) or Fulkerson (3.7%) procedures (P = .004). The overall risk of major complications was 3.0%. Hardware removal was performed in 36.7% of osteotomies and was less frequent with the Elmslie-Trillat technique (26.8%) than with the Fulkerson technique (49.0%) or complete tubercle detachment (48.3%) (P < .001).

CONCLUSIONS

Tibial tubercle osteotomy is a complex surgical procedure with a significant risk of complications. Osteotomies that involve complete detachment of the tubercle have an increased risk of complications compared with those in which a distal cortical hinge is maintained.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.

Medial patellotibial ligament (MPTL) reconstruction for patellar instability

PURPOSE

To evaluate mid-term clinical and radiographic outcomes after an original medial patellotibial ligament reconstruction in patients with patellar dislocation.

METHODS

Twenty-nine knees (27 patients, 8 males and 19 females) treated for patellar dislocation with medialization of the patellar tendon medial third combined with medial and lateral release were evaluated clinically and radiographically at a mean follow-up of 6.1±2.5 years. Trochleoplasty was performed in case of severe flat trochlea (6 knees, 21%). Aetiology of patellofemoral instability was traumatic in 6 (21%) and atraumatic in 23 (79%) knees. The mean age at first dislocation was 19.2±10.1 years. WOMAC, subjective and objective IKDC, Kujala, VAS for pain, Tegner activity and EQ-5D scores were used. Anteroposterior, lateral and 30° axial views were performed for radiographic monitoring.

RESULTS

There was a significant improvement of all clinical scores and significant reduction in knee pain. Twenty-four knees (83%) were normal or nearly normal by objective IKDC score at final follow-up. Radiographs showed a higher incidence of patella alta and flat trochlea in the atraumatic group. Severe signs of patellar osteoarthritis were found in 1 knee (3%). A higher body mass index (BMI) was correlated with worse pre-operative scores. Four knees (14%) were considered failures (2 further dislocations, 2 revision surgeries). The overall survival rate at 6 years was 0.811.

CONCLUSIONS

The presented techniques produced good clinical and radiographic results at mean 6.1 years follow-up, with 14 % failures. Signs of patellofemoral dysplasia were found in patients with atraumatic patellar dislocation. BMI was related to worse pre-operative clinical status.

LEVEL OF EVIDENCE

Retrospective study, Level IV.

Tibial Tuberosity Osteotomy: Indications, Techniques, and Outcomes

Tibial tuberosity osteotomy (TTO) is a well-described treatment option for a broad range of patellofemoral joint disorders, including patellofemoral instability, patellar and trochlear focal chondral lesions, and patellofemoral arthritis. The purpose of this article is to review the evolution of the TTO procedure, from the original Hauser procedure to the current anteromedialization procedure, as well as discuss the pertinent anatomy and radiographs that accompany this procedure. The article highlights the surgical techniques for some of the more commonly performed TTO procedures and discusses the outcomes of the various TTO techniques. Complications, as well as clinical pearls to avoid these complications, are also included.

Poor outcome at 7.5 years after Stanisavljevic quadriceps transposition for patello-femoral instability

INTRODUCTION

Congenital dislocation of the patella and recurrent symptomatic dislocation in adolescents are difficult pathologies to treat. Stanisavljevic described an extensive release procedure essentially involving medializing the entire lateral quadriceps and medial soft tissue stabilization. There are no significant series reporting the success of this method. This procedure has been performed in our institution over several years and we report our results.

METHOD

Retrospective case series. Between 1990 and 2007, 20 knees in 13 children and adolescents (mean age 12.8 years; 4-17, 7 female) with recurrent or congenital dislocation of the patella (8 knees) underwent this procedure after failed conservative treatment (mean follow-up 7.5 years; 4-16). All were immobilized in a long leg cast for 6 weeks.

RESULTS

Five knees in five patients (20 %, 1 congenital dislocation) reported their knees as improved without further dislocations. Out of the 15 knees with failures (80 %) 12 in six patients (60 %) were revised due to redislocation. Three knees in two patients (15 %) still had dislocations or subluxations, but any revision was refused. Three knees in three patients caused pain and discomfort during daily activity. Redislocation first developed after a mean of 21.3 months (4-72) postoperatively. Only one patient had returned to sport at the 12-month follow-up.

DISCUSSION

The Stanisavljevic procedure produces a mediocre success rate with our long-term follow-up series showing a failure rate up to 80 %. We therefore recommend more specific procedures dealing with the anatomical deformity such as trochleaplasty to produce superior success rates.

Rehabilitation after anteromedialization of the tibial tuberosity

Various surgical procedures are currently being used to treat symptomatic patellar instability. Distal bony realignment techniques attempt to correct malalignment by shifting the site of insertion of the patellar tendon. Tibial tuberosity anteromedialization, also known as the Fulkerson osteotomy, is a process in which the tuberosity is transferred anteriorly and medially. Although this surgical technique has been well described in the literature and the results are generally reported to be very good, the operation requires a prolonged recovery period and little has been written specifically regarding postoperative rehabilitation. This article discusses the rationale and technique for anteromedialization and emphasizes the important principals and goals of rehabilitation.

Evaluation of the modified Elmslie-Trillat procedure for patellofemoral dysfunction

The goal of this study was to evaluate the Elmslie-Trillat procedure for recurrent patellar dislocation, patellofemoral pain (with extensor mechanism malalignment), or a combination of both. Thirty-two patients underwent the modified Elmslie-Trillat procedure, consisting of a lateral retinacular release and medialization of the tibial tuberosity for recurrent patellar dislocation, patellofemoral pain, or both. Twenty-nine of 32 patients were available for follow-up. All patients were evaluated clinically and radiologically. Subjective scores were evaluated using the Cox grading system and objective scores using Fulkerson's functional knee score. Average patient age was 33 years. Mean follow-up was 45 months. Subjectively, using the Cox grading system, 10 patients (34%) had an excellent result, 8 (28%) had a good result, 8 (28%) had a fair result, and 3 (10%) had a poor result. All patients with patella dislocation had an excellent or good subjective result, while only 3 patients (34%) with the primary symptom of patellofemoral pain with extensor mechanism malalignment and 4 patients (44%) with a combination of both symptoms had a good or excellent result. Mean Fulkerson's functional knee score was excellent for patients with dislocation only, and fair for those with only pain or both pain and dislocation. The congruence angle was corrected in all patients with this technique. There were no further dislocations in our series. Two patients required hardware removal. The Elmslie-Trillat procedure is a good surgical option for treatment of recurrent patella instability following failed conservative therapy. However, the results are not as favorable for patients with patellofemoral pain without instability.

Axial linear patellar displacement: a new measurement of patellofemoral congruence

BACKGROUND

The tools for measuring the congruence angle with digital radiography software can be difficult to use; therefore, the authors sought to develop a new, easy, and reliable method for measuring patellofemoral congruence. The abstract goes here and covers two columns.

HYPOTHESIS

The abstract goes The linear displacement measurement will correlate well with the congruence angle measurement. here and covers two columns.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

On Merchant view radiographs obtained digitally, the authors measured the congruence angle and a new linear displacement measurement on preoperative and postoperative radiographs of 31 patients who suffered unilateral patellar dislocations and 100 uninjured subjects. The linear displacement measurement was obtained by drawing a reference line across the medial and lateral trochlear facets. Perpendicular lines were drawn from the depth of the sulcus through the reference line and from the apex of the posterior tip of the patella through the reference line. The distance between the perpendicular lines was the linear displacement measurement. The measurements were obtained twice at different sittings. The observer was blinded as to the previous measurements to establish reliability. Measurements were compared to determine whether the linear displacement measurement correlated with congruence angle.

RESULTS

Intraobserver reliability was above r(2) = .90 for all measurements. In patients with patellar dislocations, the mean congruence angle preoperatively was 33.5 degrees , compared with 12.1 mm for linear displacement (r(2) = .92). The mean congruence angle postoperatively was 11.2 degrees, compared with 4.0 mm for linear displacement (r(2) = .89). For normal subjects, the mean congruence angle was -3 degrees and the mean linear displacement was 0.2 mm.

CONCLUSION

The linear displacement measurement was found to correlate with congruence angle measurements and may be an easy and useful tool for clinicians to evaluate patellofemoral congruence objectively.

Reconstruction of the medial patellofemoral ligament with gracilis tendon autograft in transverse patellar drill holes

PURPOSE

We present clinical results in a case series of 44 patients with medial patellofemoral ligament (MPFL) reconstruction with 12 to 32 months' follow-up.

METHODS

Reconstruction was performed via gracilis tendon autograft looped through 2 transverse 4.5-mm drill holes in the patella and fixed at the natural MPFL insertion site on the medial femoral condyle with an interference screw. At follow-up, Kujala scores, Knee Injury and Osteoarthritis Outcome Scores, objective knee function, complications, and reoperations were assessed.

RESULTS

Only 1 patella redislocation was observed. Subluxation occurred in 3 patients, whereas 4 patients had chronic pain at follow-up, all of whom had cartilage injury at surgery. The Kujala knee function score improved overall from 46 points (range, 12 to 67 points) to 84 points (range, 62 to 100 points) at follow-up.

CONCLUSIONS

MPFL reconstruction with double transverse patella drill holes and a gracilis tendon graft provides good postoperative patellar stability. Postoperative pain seems to be related to the degree of patellofemoral injury found at surgery.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Patellofemoral Pain

Patellofemoral pain is an extremely common disorder, especially in female athletes. There is, however, no true consensus as to the cause and appropriate treatment for patellofemoral pain. This article reviews the epidemiology of patellofemoral pain as well as the proposed etiologies, including quadriceps dysfunction, static alignment disorders, and dynamic alignment disorders. The article also reviews both conservative and surgical treatment of patellofemoral pain.

Tibial tuberosity transfer for episodic patellar dislocation

Numerous surgical techniques have been described to address episodic patellar dislocations. Some of them involve the soft tissues whereas others primarily address a bony correction. Four principal anatomic factors have been identified that increase the risk for episodic patellar dislocations: trochlear dysplasia, patella alta, patellar tilt, and an excessive tibial tubercle-trochlear groove distance. A treatment algorithm has been proposed to correct each of these factors. It includes the tibial tuberosity transfer, which is able to correct both a patella alta and an excessive tibial tubercle-trochlear groove distance. The tibial tuberosity can be transferred distally or medially or more frequently a combination of both. It will realign the extensor mechanism and increase patellofemoral stability. This procedure may be associated with a medial patellofemoral ligament reconstruction in case of excessive patellar tilt or rarely with a trochleoplasty for major abnormal patellar maltracking.

Functional outcome following modified Elmslie-Trillat procedure

The aim of this study was to evaluate the mid- and long-term outcome of the modified Elmslie-Trillat procedure, as well as to detect factors affecting it. Thirty-eight patients (44 procedures) with a mean age of 31 years were included in this study. The reason for operation was patellar instability in 10 cases, anterior knee pain with malalignment of the extensor mechanism in 15 cases and a combination of both in 19 cases. Patients were followed for an average of 40 months (range=18-130 months). The functional outcome was very satisfactory or satisfactory for 73% of patients. According to Cox's criteria it was excellent in 13 cases (30%), good in 18 (41%), fair in 7 (16%) and poor in the remaining 6 (13%). Patients scored an average of 3.5 (range=2-8) in their Tegner Activity Scale, while their score in Activities of Daily Living Scale of the Knee Outcome Survey ranged from 43 to 98 (average=76). Result analysis revealed a better functional outcome when the operation was performed for patellar instability, as well as in the absence of grade 3 or 4 chondral changes in the patellofemoral joint at the time of operation. Elmslie-Trillat procedure satisfactorily restores patellofemoral stability and offers a very good functional outcome, especially in the absence of significant chondral changes in the patellofemoral joint at the time of operation.

The effects of medialization and anteromedialization of the tibial tubercle on patellofemoral mechanics and kinematics

BACKGROUND

Medialization and anteromedialization of the tibial tubercle are used to correct patellar subluxation in adults.

PURPOSE

To compare the effects of the 2 osteotomies on patellofemoral joint contact pressures and kinematics.

STUDY DESIGN

Controlled laboratory study.

METHODS

Tibial tubercle osteotomies were performed on 10 cadaveric human knees. The knees were tested between 0 degrees and 90 degrees of flexion while dynamic patellofemoral joint contact pressure and kinematic data were simultaneously obtained. Four conditions were tested: normal knee alignment, simulated increased Q angle, postmedialization of the tibial tubercle, and postanteromedialization of the tubercle.

RESULTS

An increased Q angle laterally translated the patella, shifted force to the lateral facet, and increased patella contact pressures. Both medialization and anteromedialization partially corrected the abnormal contact pressures. Medialization partially corrected the shift of force to the lateral facet induced by an increased Q angle, whereas the anteromedialization could not. Both medialization and anteromedialization corrected the patella maltracking.

CONCLUSION

Medialization and anteromedialization are equivalent in their ability to correct abnormal patellar mechanics and kinematics.

In vitro investigation of the effect of medial patellofemoral ligament reconstruction and medial tibial tuberosity transfer on lateral patellar stability

PURPOSE

Two different operative techniques for stabilizing the patella against lateral displacement movement were investigated.

TYPE OF STUDY

In vitro experimental study.

METHODS

Five human cadaver knee specimens with a normal Q-angle were mounted in a kinematic knee simulator and investigated under simulated isokinetic extension motions. Patellar movement was measured while a 100-N laterally directed subluxation load was applied to the patella. Ligament loading of the medial patellofemoral ligament was measured using a strain gauge based buckle transducer inserted in the fibers of the ligament. The knee was evaluated in an intact physiologic state, as well as after medial transfer of the tibial tuberosity, and after the medial patellofemoral ligament was transected and reconstructed using a hamstring autograft.

RESULTS

A significant reduction in lateral displacement and ligament load was observed with the use of the hamstring autograft reconstruction compared with the medial transfer of the tibial tuberosity.

CONCLUSIONS

Medial transfer of the tibial tuberosity showed no significant relief of ligament loading and stabilizing effect on patellar movement, whereas reconstruction of the medial patellofemoral ligament showed a significant stabilizing effect on patellar movement.

CLINICAL RELEVANCE

In cadaver specimens, we evaluated the effect of tibial tubercle transfer and the patellofemoral ligament and found that reconstruction of the patellofemoral ligament alone was sufficient to restore stability in a cadaveric model. Additionally, we found that the flexion angle had little effect on the loading of the medial patellofemoral ligament autograft, which would support early mobilization of patients after surgery. We found that the graft was not unduly loaded.

Early results of one-stage knee extensor realignment and autologous osteochondral grafting

We treated 49 patients with recurrent patellar dislocations or persistent patellar subluxations. Chondral defects were graded according to the International Cartilage Repair Society (ICRS). Thirty patients (group I) had chondral defects grade I or II, and 19 patients (group II) had chondral defects grade III or IV. All patients were treated with proximal and distal realignment of the knee extensor mechanism, but group II also had a simultaneous autologous osteochondral grafting of the chondral defect. Patients were followed for 2 years and clinically assessed using the Marshall score comparing the two groups. Apart from a slower recovery in group II, the clinical and functional results were almost the same at the final follow-up.

Treatment outcome of extensor realignment for patellofemoral dysfunction

Patellofemoral pain remains one of the most common musculoskeletal disorders encountered in orthopaedic practice. In this retrospective clinical study, 108 knees in 98 patients with patellofemoral pain due to malalignment were treated using a combined proximal and distal realignment technique. The results were evaluated at an average of 29.2 (1-9.2 years) months postoperatively. At final evaluation using the modified Trillat grading scale, good or excellent results were obtained in 88 (81.4%) of the knees treated. Second-look arthroscopy performed in 65 (60.2%) knees demonstrated good patellar tracking and Grade II articular changes were noted in 16 (14.8%) of the patellofemoral joints examined. Complications noted included anterior compartment syndrome with foot drop in one case and arthrofibrosis in another. We conclude that extensor realignment surgery with a combined proximal and distal realignment procedure is a reliable technique for patellofemoral pain secondary to malalignment.

A new technique for reconstructing the medial patellofemoral ligament

Many surgical techniques exist for treating patella instability. Over recent years, attention has focussed on reconstruction of the medial patellofemoral ligament (MPFL). We report a procedure involving a lateral release, distal realignment of the tibial tubercle and anatomic reconstruction of the MPFL using a graft composed of a redundant strip of medial retinacular tissue. Nineteen patients (twenty-one knees) with chronic patellofemoral instability who had failed conservative treatment underwent this procedure and were assessed clinically and radiologically at an average of 23 months post-operation. No patients were lost to follow-up. There was no recurrence of subluxation or dislocation. All achieved levels of activity comparable to or improved compared to pre-operative uninjured levels. This combined procedure incorporating a previously un-described method of reconstructing the MPFL gives superior results compared to previous studies. No graft donor site morbidity occurred and patient outcome scores, especially objective stability of the patella to lateral shift, were excellent.

Évaluation subjective des résultats du traitement chirurgical des instabilités rotuliennes

PURPOSE OF THE STUDY

We analyzed functional outcome after surgical treatment for patellar instability.

MATERIAL AND METHODS

This study included 130 patients (174 knees) treated between 1988 and 1999. Minimum follow-up after surgery was two Years, mean five years (range 24-152 months). The IKDC 1999 subjective evaluation chart was used. This chart has ten items to establish level of sports activity and functional status of the knee for daily life activities. One hundred ten patients (84.5%) responded to the questionnaire.

RESULTS

Eighty-eight patients were seen for clinical assessment and 22 were questioned by telephone: 104 patients (94.5%) were satisfied or very satisfied, five (4.5%) were dissatisfied, and one was disappointed. We evaluated results on the basis of pain (37.6% with climate-related pain or discomfort), residual effusion, and sensation of blocked knee (15.8%), as well as daily activities (68% with discomfort when kneeling), and sports activities (with level of activity).

DISCUSSION

The patients' subjective assessment showed that surgical treatment with medialization and/or lowering of the anterior tibial tuberosity is effective with a good or excellent rate of satisfaction. The quality of these results was directly related to careful individualization of the lesions with systematic analysis of factors leading to patellar instability (trochlear dysplasia, patellar height, quadriceps dysplasia, TA-GT measures, length of the patellar tendon).

The use of stereolithography for an unusual patellofemoral disorder

A patient with habitual patellar dislocation which was not treated successfully by the Elmslie-Trillat procedure is described. In the knee, a unique morphologic feature of the patellofemoral joint was suspected as a cause, and a stereolithographic model was produced from the patient's computed tomography data to determine the pathologic features. Because the solid model confirmed the speculation, additional surgery was done to modify the geometry of the joint. In the surgery, cancellous bone was removed below the cartilage, and the geometry of the cartilage was modified with the subchondral bone, taking advantage of the elasticity of the bone and cartilage. The second surgery eliminated maltracking of the patella and a satisfactory result was obtained. Therefore, stereolithography is useful for the treatment of atypical patellofemoral disorders, allowing an understanding of the pathologic features and dynamic simulation of the surgery. The surgical procedure could be a promising method to alter the joint geometry without impairing the cartilage.

Patellofemoral malalignment: looking beyond the viewbox

A clear understanding of the pathophysiology of anterior knee pain is inhibited by the use of imprecise, poorly defined, and often interchanged words, such as malalignment, patellar alignment, maltracking, subluxation, dislocation, and congruence. The literature is filled with articles regarding the diagnosis, "malalignment of the patella," most of which give no precise diagnosis. This article presents a definition of malalignment and a plea for rational descriptive and scientific analysis. Much of what is described is based on theory, not facts. These ideas are supported by clinical experience and logical analysis, but very little in the way of scientific data. Most of the data involve radiographic images, which present only one piece of the puzzle.

Functional evaluation of the modified Elmslie-Trillat procedure for patello-femoral dysfunction

A series of 28 knees in 27 patients were evaluated at an average of 36 months following surgical treatment for patella dislocation, patello-femoral pain, or a combination of both. All cases were treated by the modified Elmslie-Trillat procedure, which involves a lateral retinacular release and medialisation of the tibial tubercle on a distal pedicle. The evaluation included subjective, objective (Fulkerson and Kujala functional knee scores) and radiographic assessments. Subjectively, eight knees (28%) had excellent results, nine knees (33%) good results and seven knees (25%) fair results, accounting for an overall improvement of 86% over the preoperative status. All the knees in patients with a primary symptom of patella dislocation had an excellent or good subjective result, whilst only four knees (40%) in those patients with a primary symptom of pain and four knees (44%) in those with both pain and dislocation had a good or excellent result. The mean objective knee score was excellent for patients with dislocation only, and fair for those with only pain or both pain and dislocation. There have been no further episodes of dislocation in all patients. Six knees (21%) required later screw removal. The modified Elmslie-Trillat procedure produces a favourable outcome in patients with patella dislocation.

Q-angle influences tibiofemoral and patellofemoral kinematics

Numerous surgical procedures have been developed to correct patellar tracking and improve patellofemoral symptoms by altering the Q-angle (the angle between the quadriceps load vector and the patellar tendon load vector). The influence of the Q-angle on knee kinematics has yet to be specifically quantified, however. In vitro knee simulation was performed to relate the Q-angle to tibiofemoral and patellofemoral kinematics. Six cadaver knees were tested by applying simulated hamstrings, quadriceps and hip loads to induce knee flexion. The knees were tested with a normal alignment, after increasing the Q-angle and after decreasing the Q-angle. Increasing the Q-angle significantly shifted the patella laterally from 20 degrees to 60 degrees of knee flexion, tilted the patella medially from 20 degrees to 80 degrees of flexion, and rotated the patella medially from 20 degrees to 50 degrees of flexion. Decreasing the Q-angle significantly tilted the patella laterally at 20 degrees and from 50 degrees to 80 degrees of flexion, rotated the tibia externally from 30 degrees to 60 degrees of flexion, and increased the tibiofemoral varus orientation from 40 degrees to 90 degrees of flexion. The results show that an increase in the Q-angle could lead to lateral patellar dislocation or increased lateral patellofemoral contact pressures. A Q-angle decrease may not shift the patella medially, but could increase the medial tibiofemoral contact pressure by increasing the varus orientation.

Articular cartilage contact pressure after tibial tuberosity transfer. A cadaveric study

Medial transfer of the tibial tuberosity has been commonly used for treatment of recurrent dislocation of the patella and patellofemoral malalignment. In this study, six fresh human cadaveric knees were used. Static intrajoint loads were recorded using Fuji Prescale pressure-sensitive film for contact pressure and contact area determination in a closed kinetic chain knee testing protocol. Peak pressures, average contact pressures, and contact areas of the patellofemoral and tibiofemoral joints were calculated on native intact knee specimens and after tibial tuberosity transfer. All native intact knee specimens had a normal Q angle. Medialization of the tibial tuberosity significantly increased the patellofemoral contact pressure. Medial displacement of the tibial tuberosity also significantly increased the average contact pressure of the medial tibiofemoral compartment and changed the balance of tibiofemoral joint loading. The results of our study suggest that caution should be used when transferring a patellar tendon in the face of a preexisting normal Q angle as this will result in abnormally high peak pressure within the tibiofemoral joint. Overmedialization of the tibial tuberosity should be avoided in the varus knee, the knee after medial meniscectomy, and the knee with preexisting degenerative arthritis of the medial compartment.

Delayed proximal repair and distal realignment after patellar dislocation

Twenty athletes with distal malalignment who sustained unilateral traumatic patellar dislocation remained impaired by chronic instability. Surgery was performed at a mean age of 18 years. Posttraumatic attenuation of the medial patellofemoral ligament was repaired near the margin of the patella in 10 knees and avulsion or attenuation posterior to the vastus medialis obliquus in 10 knees. Advancement of the medial patellomeniscal ligament at the margin of the patella and normalization of the Q angle to 10 degrees by tibial tubercle osteotomy were performed in each knee. Distal lateral retinacular release without release of the normal vastus lateralis tendon was performed. Results were judged according to Turba et al, and activity levels were evaluated per guidelines of the International Knee Documentation Committee. Eighteen (90%) patients achieved good or excellent results and were unimpaired at a minimum of 24 months. Two patients achieved fair subjective results with some impairment in vigorous activity. There was no recurrent instability. Radiographically, the mean preoperative patellofemoral congruence angle improved from 20 degrees to 0 degree. Athletes who sustain an initial traumatic patellar dislocation after physeal closure and in whom conservative management fails can be treated successfully by repair of the medial patellofemoral ligament at the site of disruption and advancement of the medial patellomeniscal ligament combined with correction of an elevated Q angle.

The three-in-one proximal and distal soft tissue patellar realignment procedure. Results, and its place in the management of patellofemoral instability

The three-in-one procedure for extensor mechanism realignment of the knee combines lateral release, vastus medialis obliquus muscle advancement, and transfer of the medial one-third of the patellar tendon to the tibial collateral ligament. We observed 37 patients (42 knees) receiving this treatment at a minimum 25-month follow-up (range, 25 to 85 months; mean, 44). Thirty-two of 42 knees (76%) with recurrent patellar dislocation had good or excellent results after surgery. Redislocation occurred in four knees (9.5%). Skeletal immaturity, chondral damage, and generalized ligament laxity did not seem to affect outcome. Thirty patients (37 knees) were studied 2 years earlier as well (mean follow-up, 29 months). When comparing the results 2 years later, there was a significant deterioration in outcome over time. These results are comparable with the published results for other techniques of patellar stabilization. We describe the place of the three-in-one operation in our surgical protocol for patellofemoral instability, which is based on the principle that a procedure should be selected to address the underlying pathologic features in an individual case rather than always using one operation for all cases.

Biomechanical analysis of flat and oblique tibial tubercle osteotomy for recurrent patellar instability

Both flat (Elmslie-Trillat) and oblique (Fulkerson) osteotomy techniques are successful in treating patellar instability episodes by moving the tibial tubercle medially. The oblique osteotomy also results in anterior displacement that decreases patellofemoral forces. Recent reports have described proximal tibial fractures occurring during early weightbearing after oblique osteotomy. We performed oblique and flat osteotomies on 13 pairs of fresh-frozen cadaveric knees. The knees were then tested to failure on a materials testing system by exerting a load through the quadriceps tendon at a rate of 1000 N/sec to simulate a stumble injury. The failure mechanism for flat osteotomies was more likely to be tubercle "shingle" fracture, while oblique osteotomies more frequently failed through a tibial fracture or fixation failure in the posterior tibial cortex. Mean load to failure was significantly higher in the flat osteotomy specimens (1639 N versus 1166 N), as was total energy to failure (224 N.m versus 127 N.m). There was no significant difference in stiffness (87 N/cm versus 74 N/cm). We recommend the flat osteotomy for patients with isolated recurrent patellar instability and the oblique osteotomy in patients who have concomitant patellofemoral pain or articular degenerative changes. When an oblique osteotomy is used, we recommend postoperative brace protection and restricted weightbearing until the osteotomy heals.