Recurrent Patellofemoral Dislocation Research Articles

Trochleoplasty Provides Good Outcomes for Recurrent Patellofemoral Dislocations with No Clear Superiority across Different Techniques.

Background: Literature is sparse on outcome comparisons between different trochleoplasty techniques in the treatment of patella instability. To date, it is unclear whether there is a technique that offers superior outcomes. This systematic review and meta-analysis aims to compare and evaluate the outcomes of trochleoplasty techniques in the treatment of patellofemoral instability in trochlea dysplasia to establish whether there is an ideal choice of trochleoplasty technique for superior outcomes. Methods: 21 studies involving 880 knees were included. The mean age of the patients was 21.7 years (range 8-49 years). Mean follow-up timeframe of 43.5 months (range 8.8-100 months). Clinical outcomes assessed included rates of recurrence of patellofemoral dislocation, patient satisfaction, Kujala score, International Knee Documentation Committee (IKDC) score, Tegner score, and Lysholm score. Egger's test showed no publication bias across all outcomes assessed. Results: Favourable results were seen across all outcomes assessed and patient satisfaction. Improvements were seen with Kujala, IKDC, and Lysholm scores. Tegner scores showed good return to function. Post-operative dislocation and complication rates were low across the different techniques. Meta-regression for Kujala and IKDC scores showed good outcomes regardless of trochleoplasty technique used (Kujala, p = 0.549, relative risk 492.06; IKDC, p = 0.193, RR 0.001). The exact risk that trochleoplasty poses to the cartilage remains uncertain, as no study had a conservatively managed arm for comparison. Conclusions: Trochleoplasty yielded good outcomes irrespective of technique used with no clear superiority demonstrated in any technique in terms of outcome scores, satisfaction, post-operative dislocation rates or complications.

Predictive Scoring for Recurrent Patellar Instability After a First-time Patellar Dislocation.

Patellofemoral instability is a common acute knee injury seen in the pediatric population. First-time patellar dislocations usually undergo conservative management, but ~15% to 80% of patients experience recurrent instability. This study aims to develop a prediction model using radiographic parameters of the patellofemoral joint seen on computed tomography scans in different degrees of knee flexion, to determine the risk of recurrence after the first episode of patellofemoral instability. A 12-year retrospective case-control study was performed. All patients in a single institution aged 18 years or younger who had a computed tomography patellar tracking scan performed for patellar instability were included. Predictors included in the score were determined through backward logistic regression and compared using receiver operating characteristic curve analysis. This study revealed that recurrent dislocation in first-time patellofemoral dislocation could be accurately predicted using the prediction score that consisted of age, tibial tubercle-trochlear groove distance and congruence angle at 10- and 20-degree flexion. The sensitivity of the score was 100% and specificity was 73.3%. Three diagnostic zones were identified and used to categorize patients into low-, intermediate-, and high-probability groups. This study presented a scoring system that incorporated radiographic knee kinematics in the risk assessment for recurrent patellofemoral instability for patient stratification. The scoring system could guide the decision for early surgical intervention after the first-episode patellofemoral dislocation for patients at high risk of recurrent patellofemoral dislocation.

Weight bearing versus conventional CT for the measurement of patellar alignment and stability in patients after surgical treatment for patellar recurrent dislocation

PurposeTo compare weight-bearing cone-beam computer tomography (CBCT) and conventional computer tomography (CT)-based measurements of patellofemoral alignment and stability in patients surgically treated for recurrent patellar dislocation. These scans implied respectively single-leg up-right posture, the knee flexed, and lower limb muscles activation, versus supine position with the knee extended.MethodsA total of 17 patients (11 males/6 females) after surgical reconstruction with fascia lata allograft for recurrent patellofemoral dislocation were analyzed at 60-month follow-up. Tilt and congruence angles and tibial tuberosity–trochlear groove (TT-TG) offset were measured on images obtained from CBCT and conventional CT scans by three independent and expert radiologists. Paired t tests were performed to compare measurements obtained from the two scans. Inter-rater reliability was assessed using a two-way mixed-effects model intra-class correlation coefficient (ICC).ResultsOnly TT-TG offset was found significantly smaller (p < 0.001) in CBCT (mean 9.9 ± 5.3 mm) than in conventional CT (mean 15.9 ± 4.9 mm) scans. ICC for tilt and congruence angles and for TT-TG offset ranged between 0.80–0.94 with measurements in CBCT scans, between 0.52 and0.78 in conventional CT.ConclusionIn patients surgically treated for recurrent patellar dislocation, TT-TG offset was found overestimated with conventional CT. All measurements of patellofemoral stability and alignment were found more consistent when obtained with weight-bearing CBCT compared to conventional CT.

High failure rate 10.8years after vastus medialis transfer and lateral release (Green's quadricepsplasty) for recurrent dislocation of the patella.

In adolescent patients with recurrent patellar dislocation, the Green's quadricepsplasty stabilizes the patella in a combination of a lateral release, a transfer of the medial head of the quadriceps onto the lateral part of the patella and an imbrication of the medial patellar retinaculum and joint capsule. This study aimed to evaluate the long-term performance, considering re-dislocations and functional outcomes. We hypothesized a high failure rate in the long term. In this single surgeon and single center study 26 knees in 23 patients (mean age 14.2years; 4-22years, 18 females) with recurrent patellofemoral dislocation underwent a vastus medialis transfer, medial reefing and lateral release as it was described by Green in 1965 with a mean follow-up 10.8years (6-24years). Clinical assessment was carried out with an IKDC-score (international knee documentation committee) and a self-assessment for each knee separately. The radiologic evaluation included measurement of the patella height, the grade of trochlear dysplasia and the sulcus angle. In 12 of 26 cases (46.2%) the patella did not re-dislocate after vastus medialis transfer and lateral release. In 11 of 26 cases (42.3%), the patients described the function of their knees as normal or nearly normal according to IKDC after the surgical treatment without any re-dislocation. In 14 of 26 cases (53.8%), the patella re-dislocated. 7 of these 14 cases underwent a revision operation. Re-dislocations occurred after a mean interval of 21months after the index procedure. In only 2 of 26 cases (7.7%) the patients returned to sports. Green's procedure to stabilize patellofemoral instabilities results in a high failure rate on the long-term and low subjective assessments. We do not recommend performing vastus medialis transfer, medial imbrication and lateral release as a standalone technique. IV.

Compared outcomes 16 and 25 years after lateral wedge augmentation trochleoplasty: Rate of recurrent dislocation and progression to osteoarthritis

BackgroundLateral wedge augmentation trochleoplasty (LWAT) was the earliest described trochleoplasty technique but was gradually replaced by other methods for the treatment of patello-femoral instability with trochlear dysplasia. Data on the outcomes of this procedure in adults are limited. We therefore performed a retrospective study in patients managed by LWAT to assess (1) clinical (recurrent instability and functional scores), (2) and radiological (patello-femoral osteoarthritis) outcomes. HypothesisLWAT is associated with a low long-term rate of recurrent patello-femoral dislocation and with no risk of progression to severe patello-femoral osteoarthritis. Material and methodsBetween 1988 and 1995, LWAT was performed on 66 knees in 58 patients to treat patello-femoral instability with trochlear dysplasia. Among them, 17 knees in 13 patients were re-evaluated 16 then 25 years after surgery and were included in the study. At both time points, the following were recorded: stability, pain, the Lille patello-femoral function score, and changes in radiographic and computed tomography findings. In addition to LWAT, Insall's realignment vastus medialis advancement was performed in 4 cases, sartorius muscle transposition in 9 cases, and anterior tibial tubercle osteotomy in 10 cases. ResultsNo episodes of patello-femoral dislocation were recorded during the 25-year follow-up. The mean Lille patello-femoral function score (0 worst to 100 highest) was 90±15 (range, 48–99) after 16 years and 86±23 (range, 33–94) after 25 years. After 16 years, 8/17 knees had evidence of patello-femoral osteoarthritis, which was Iwano stage 1 in 7 cases and Iwano stage 2 in 1 case. Patello-femoral osteoarthritis was noted in 12 of 13 knees after 25 years but was mild (Iwano stage 1 or 2) in 8 cases. After 25 years, arthroplasty had been performed for 4 of the 17 knees, with 2 cases each of patello-femoral arthroplasty and total knee arthroplasty. ConclusionLWAT is a reliable procedure that provides sustained protection against patello-femoral dislocation and good functional scores when used to treat patello-femoral instability due to trochlear dysplasia. Our results do not support claims that LWAT may be associated with high rates of severe osteoarthritis even after more than 20 years. Level of evidenceIV, retrospective observational study with no control group.

The Outcomes of Isolated Lateral Release in Patellofemoral Instability: A Systematic Review and Meta-Analysis.

There have been conflicting reports regarding the outcomes of lateral release when used in the management of patellofemoral instability. This systematic review and meta-analysis therefore aims to evaluate the outcomes of isolated lateral release in the management of patellofemoral instability. The review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All studies that reported the outcomes of isolated lateral release for recurrent patellofemoral dislocations were included. A total of 10 publications were included, with 204 knees. All studies consistently reported a decrease in the rates of patellofemoral dislocation (odds ratio [OR] < 0.01; 95% confidence interval [CI]: <0.01-0.01) and an increase in the odds of having a good outcome (OR 0.01; 95% CI: <0.01-0.02) after lateral release. All studies also consistently reported a similar number of patients participating in sports postoperatively as compared with preinjury (OR 2.78; 95% CI: 0.53-14.68). A total of 28 (14.1%) out of 198 patients had postoperative dislocation. Of these patients, 15 required a secondary procedure for patellofemoral realignment; however, all patients who had their eventual outcomes reported still had a good outcome postoperatively. Isolated lateral release can lead to good short- to middle-term outcomes when used in the management of recurrent patellofemoral dislocations. The procedure can lead to a significantly decreased rate of recurrence of patellofemoral dislocations, a significantly increased rate of good outcomes, and a similar number of patients being able to participate in sports as compared with the number of patients participating in sports prior to having patellofemoral dislocations. An isolated lateral release could therefore potentially serve as a simple and relatively low-risk procedure that could be performed as a first-line surgical management in selected patients with patellofemoral instability, allowing them to possibly avoid a more complex and major operation. This is a Level IV study.

Lateral retinacular release via a prolonged incision versus arthroscopic lateral retinacular release in osteofascial medial patellofemoral ligament reconstruction for recurrent patellofemoral dislocation

Objective To compare the short-term outcomes between lateral retinacular release (LRR) via a prolonged incision versus arthroscopic LRR in osteofascial medial patellofemoral ligament reconstruction (MPFL-R) for recurrent patellofemoral dislocation. Methods From May 2012 to March 2015, 51 patients with recurrent patellofemoral dislocation were treated at the Department of Joint Surgery, The Third Affiliated Hospital to Hebei Medical University. They were 16 males and 35 females, aged from 20 to 36 years (mean 27.2 years). Of them, 28 underwent LRR via a prolonged incision in MPFL-R (incision group) and 23 did arthroscopic LRR in MPFL-R (microscopic group). Imaging changes were assessed by comparing preoperative and postoperative values of patella extensibility, patellar tilt angle, trochlear groove angle and tibial tuberosity-trochlear groove spacing (TT-TG); the knee joints were scored with Kujala and Lysholm functional rating systems at the last follow-ups. Results The 2 groups were compatible due to insignificant differences in the general data between them preoperatively (P>0.05). The 51 patients were followed up for 10 to 32 months (average, 20 months). The rate of dislocation in the incision and microscopic groups were 0 and 8.7% (2/23), respectively. There were no such complications in either group as patellar fracture, deep venous thrombosis of the lower extremity or limited joint extension or flexion. The last follow-ups revealed that no patients in either group were inflicted with patellofemoral re-dislocation. In the incision group, the patella extensibility, patellar tilt angle, Kujala score and Lysholm score were, respectively, 19.65%±0.75%, 12.39°±0.76°, 56.37±2.94 points and 51.64±6.22 points preoperatively, and 10.34%±0.60%, 8.83°±0.89°, 92.68±2.75, and 90.71±1.91 points postoperatively; in the microscopic group, the patella extensibility, patellar tilt angle, Kujala score and Lysholm score were, respectively, 19.56%±0.62%, 12.35°±0.66°, 57.46±3.08 points and 52.20±6.94 points preoperatively, and 10.24%±0.66%, 8.78°±0.92°, 92.53±3.32 points and 90.41±2.90 points postoperatively. There were significant differences between the preoperative and postoperative values in both 2 groups (P 0.05). There were no significant differences between the 2 groups in all the above preoperative and postoperative values (P>0.05). Conclusion In MPFL-R for recurrent patellofemoral dislocation, both LRR via a prolonged incision and arthroscopic LRR can improve the patellofemoral joint alignment and stability of the tibia, leading to good short-term outcomes. Key words: Arthroscopy; Patellar ligament; Patellar dislocation; Lysis

Medial patellofemoral ligament (MPFL) reconstruction in combination with a modified grammont technique leads to favorable mid-term results in adolescents with recurrent patellofemoral dislocations

PurposeThe aim of the present study is to present the outcome of a cohort of adolescent patients with trochlear dysplasia and elevated tibial tuberosity trochlear groove (TTTG) distance suffering from recurrent patellar dislocation. Treatment consisted of medial patellofemoral ligament (MPFL) reconstruction and a modified Grammont procedure.MethodsMRI examinations were obtained pre- and postoperatively. Trochlear dysplasia was classified according to Déjour, and TTTG was measured on MRI. The Tegner Activity Scale and the Kujala Knee Score were assessed preoperatively and at follow-up. The Kujala Knee score and the IKDC 2000 knee score were documented at follow-up (median 50, range 20–61 months; SD 16.6).ResultsSeven knees of six patients (median age 16.5 years, range 14–17 years) with trochlear dysplasia and elevated TTTG distance (median 17 mm, range 16.1–21.9 mm; SD 2.8) were treated. Trochlear dysplasia was classified as Déjour type A in 1, type B in 5, and type C in 1 knee. The Kujala Knee Score significantly increased from values of 55 (range 17–88; SD 25.9) to 94 (range 73–100; SD 9.1) at follow-up (p = 0.028). TAS improved from preoperative 2 (range 0–7; SD 2.5) to 5 (range 4–9; SD 1.8) at follow-up (p = 0.034). Median IKDC 2000 Knee Score at follow-up was 89 (range 61–100, SD 13.4). No re-dislocations were encountered.ConclusionIn selected adolescents with recurrent patellofemoral instability, MPFL reconstruction in combination with a modified Grammont technique yields excellent functional outcome and could, therefore, help to avoid major procedures, such as osteotomies.Level of evidenceTherapeutic, Level IV.

Medial Patellofemoral Ligament Reconstruction

Objectives:Recurrent patellofemoral dislocation is usually a multifactorial pathology. Different surgical techniques have been described according to the etiology of dislocation. In absence of a severe malalignment or an anatomical patellofemoral dysplasia, reconstruction of Medial Patello-femoral Ligament (MPFL) can restore the normal tracking of the patella, avoiding lateral excursion. The purpose of this study was to evaluate clinical results and complications in patients who underwent a MPFL reconstruction.Methods:We retrospectively evaluated 19 patients who underwent an anatomic MPFL reconstruction using autologous semitendinosus graft between 2007 and 2012. Exclusion criteria were patients with less than three years of follow-up and those with an associated procedure such as distal realignment or trochleoplasty. Clinical outcomes were measured using Kujala score and return to sport rate. We registered the postoperative complications and recurrence rate.Results:Nine patients were men and 10 women with a mean age of 25 years. Average follow-up was 5.8 years. Nine patients (47.4%) returned to their previous sport level, 8 (42.1%) changed to another sport or decreased their level and 2 (10.5%) were unable to practice any sports at all. Kujala score improvement was from 62.8 preoperative to 88.8 postoperative. One patient decreased the Kujala score. Eighty-nine percent of patients were satisfied with their outcome. One patient had a patellar fracture and four developed an arthrofibrosis and required mobilization under anesthesia. No recurrences were registered.Conclusion:Isolated MPFL reconstruction for recurrent patellofemoral dislocation is an effective alternative in absence of severe malalignment or anatomical dysplasia. Although no recurrences where registered at minimum 3-year follow-up, almost half of the patients were not able to return to their previous sport level.

Trochleoplasty as a Solitary Treatment for Recurrent Patellar Dislocation Results in Good Clinical Outcome in Adolescents

Background: The essential static patellar stabilizer is a normal-shaped trochlear groove. A dysplastic groove destabilizes the patella. Trochleoplasty approaches this underlying condition and reshapes the trochlea. However, studies have reported on trochleoplasty for revision cases or as accompanied by other interventions. The effect of trochleoplasty alone remains unexplained. Purpose: To introduce trochleoplasty as a stand-alone treatment for recurrent patellar dislocation and to compare its pre- to postoperative functional and clinical variables. Study Design: Case series; Level of evidence, 4. Methods: A trochleoplasty was performed in 50 knees (27 right) in 44 patients (30 females; mean ± SD age, 15.6 ± 2.0 years). The indication for surgery was recurrent patellar dislocation not responding to nonoperative treatment (>6 months), with types B through D dysplasia and closed or closing physes in adolescents aged 10 to 20 years. Assessment included J-sign and apprehension test, Kujala and Lysholm scores, patients’ subjective assessment and activity level according to the International Knee Documentation Committee questionnaire, and patients’ overall satisfaction. The Caton-Deschamps ratio and the lateral condyle index were measured. Pre- versus postoperative values were compared with a paired Wilcoxon signed-rank test. The minimum follow-up was 24 months (33 ± 10.6 months). Results: The Kujala score improved from 71 preoperatively to 92 postoperatively (P < .001) and the Lysholm score from 71 to 95 (P < .001). Patients’ subjective assessment improved at the final follow-up as compared with that preoperatively (P < .001). Most patients enhanced their activity (P < .001), and their overall satisfaction increased postoperatively (P < .001). Preoperatively, there was a positive J-sign in 45 knees and a positive apprehension test in 41 knees. Both markers disappeared postoperatively in 39 and 33 knees, respectively, leaving 6 knees with a positive J-sign and 8 knees with a positive apprehension test (P < .001). One patella redislocated postoperatively after 38 months. Four patients required a single arthroscopic debridement. Conclusion: In this study, trochleoplasty as a solitary treatment for recurrent patellofemoral dislocations in patients with trochlear dysplasia resulted in good clinical outcomes if severe torsional and axial malalignment was excluded. Kujala and Lysholm scores increased postoperatively, as well as subjective International Knee Documentation Committee assessment of outcomes, activity level, and overall satisfaction.

Arthroscopy-assisted treatment of recurrent patello-femoral joint dislocation

Objective To evaluate arthroscopy-assisted release of the lateral retinaculum and reefing of the interior retinaculum for treatment of recurrent patello-femoral joint dislocation.Methods From January 2003 to December 2008, 78 cases of recurrent patello-femoral joint dislocation were treated under arthroscopy.They were 23 men and 55 women, with a mean age of 20.3 years (range, 11 to 45 years).Their recurrence of dislocation averaged 5 times.Operative release of the lateral retinaculum and reefing of the interior retinaculum were performed under arthroscopy for all the patients.Auxiliary Goldthwait-Roux procedures were conducted in addition in 13 cases, and auxiliary improved Goldthwait-Roux procedures in 26 cases.We evaluated their subjective symptoms and objective signs, recurrence of patello-femoral joint dislocation, X-ray examinations and functional rehabilitation of the knee joint during the first 3 months, and at 6 and 12 months postoperation.Results Of the 78 cases, 65 were followed up for a mean of 47.3 months (from 19 to 76 months).All the patients were satisfied with the therapeutic effect.Recurrence of dislocation was no longer observed.Seven cases experienced slight pain after excessive motion.The flexion was slightly limited in 5 cases.Six cases reported a sense of patello-femoral malposition.By the Bostman evaluation system, the 65 cases scored 18.5 ±4.5 and 27.5 ±2.5 before and after surgery respectively, showing a statistically significant difference(P=0.018).By the Lysholm evaluation system, they scored 42.3±6.1 and 91.4±4.3 before and after surgery respectively, also showing a statistically significant difference (P = 0.026).Conclusion For treatment of recurrent patello-femoral joint dislocation, arthroscopy-assisted release of the lateral retinaculum and reefing of the interior retinaculum, as well as the auxiliary Goldthwait-Roux or improved Goldthwait-Roux procedures for necessary cases, has the merits of minimal invasion and rapid recovery. Key words: Arthroscopy; Patella; Dislocation; Surgical procedures, operative

Modified Fulkerson osteotomy in recurrent patellofemoral dislocations

We evaluated the results of a modified Fulkerson technique performed for the treatment of recurrent patellofemoral dislocations. The study included 17 knees of 16 patients (11 males, 5 females; mean age 25 years; range 15 to 43 years) who were operated on by the same surgeon for patellofemoral alignment disorders. The mean duration of complaints was 3.4 years (range 1 to 12 years). Preoperatively, the number of recurring dislocations were 1 to 5 in three knees, 6 to 10 in five knees, and more than 10 in nine knees, and all the patients had a positive apprehension test and a Q angle exceeding 15 degrees. All the knees were assessed by preoperative and postoperative radiographs and computed tomography, which showed both subluxation and patellar tilt in all the knees, and trochlear dysplasia in two knees preoperatively. During surgery, diagnostic arthroscopy was performed in all the patients. The skin incision consisted of two horizontal incisions for cosmetic reasons. Surgical treatment was comprised of lateral patellar release to correct patellar tilt, and a modified Fulkerson osteotomy to correct patellofemoral malalignment, and medial plication in three knees. The patellofemoral congruity following lateral release, and the position of the patella following osteotomy and anteromedialization of the tibial tuberosity were checked arthroscopically. On control examinations, the patients were administered functional scoring questionnaires developed by Kujala et al. and Crosby and Insall. Radiographic grading of osteoarthritis was made according to the classification developed by Iwano et al. and modified by Palmer et al. The mean follow-up period was 2.6 years (range 24 to 53 months). During arthroscopy, eight knees had severe (Outerbridge grade III-IV) and nine knees had moderate (grade I-II) retropatellar cartilage damage. Follow-up evaluations showed effusion in two knees, subluxation in two knees, and a positive apprehension test in three knees. The mean flexion loss was 8 degrees (range 0 degrees to 20 degrees ). One patient who had an extension loss of 10 degrees regained full extension following a six-week physical therapy program. Postoperative computed tomography scans showed that patellar tilt and subluxation were corrected in all but two knees. Preoperative radiographies showed degenerative arthritis in the tibiofemoral joint in one knee (5.9%), and in the patellofemoral joint in seven knees (41.2%). The number of knees with degenerative changes increased postoperatively to three knees (17.3%) in the tibiofemoral joint, and to 11 knees (64.7%) in the patellofemoral joint. According to the Crosby-Insall scoring system, five knees had excellent, seven knees had good, and five knees had moderate scores. The mean Kujala score was 82.6 (range 44 to 100) postoperatively. Our results show that, with appropriate indications, the modified Fulkerson method is associated with successful results in the treatment of recurrent patellofemoral dislocations.

Critical assessment of indications for arthroscopic lateral release and medial tightening of the knee joint

Based on the results of a retrospective study of 50 patients with mild lateral tracking and lateral compression of the patella (32 patients) and recurrent patellofemoral dislocation (18 patients), we present the technique, the results, the complications and the indications for the endoscopic lateral retinacular release and medial drawing tight of the capsule. The average age of the patients was 28.8 years (range: 10-53). At time of follow-up (m = 51 months) the patients were examined clinically as well as radiologically. The results were scored according to a score by Crosby and Insall. 73% of the patients with mild lateral tracking and lateral compression (lateral release) were satisfied with the operative results (visual analogue scale), as well as 66.6% of the patients with recurrent patellofemoral dislocation (lateral release and medial drawing tight of the capsule). Only 40% of the patients with patellofemoral arthritis (lateral release) reported about an improvement of this procedure. The score showed significantly good results but didn't raise the differences in between the groups of different indications. 28% of the patients showed an abnormal lateral tracking of the patella in active motion, the passive patella-glide-test (Hughston) raised a patella-hypermobility to the lateral side in 36% of the cases and to the medial side in 76%. X-rays of both knees showed an increased lateral patellofemoral angle of 10.8 degrees and an increased sulcus angle of 144 degrees. There was no progression in osteoarthritis in the operated side of the patellofemoral joint found. Complications revealed in a high number of hemarthrosis right after the operation, in 2 cases an open revision was necessary. According to our results patients with patella compression syndrome without patellofemoral arthritis and patients with recurrent luxation or subluxation of the patella are good candidates for endoscopic lateral release and eventually medial drawing tight of the capsule. In a young population the endoscopic lateral release is a relatively simple surgical procedure making an open technique in failed cases possible.

CT changes after trochleoplasty for symptomatic trochlear dysplasia

Trochlear dysplasia is an important risk factor for patellar instability. Because of a decreased trochlear depth in combination with a low lateral femoral condyle, the patella cannot engage properly in the trochlea. Trochleoplasty is a surgical procedure, which strives to correct such bony abnormalities. The aim of this study was to describe morphological features of trochlear dysplasia and the corrective changes after trochleoplasty on CT scan. The study group consists of 17 knees with trochlear dysplasia having undergone trochleoplasty for recurrent patellofemoral dislocation at a mean age of 22.4 years. The evaluation consisted in pre- and postoperative measurements on the proximal and distal trochlea on transverse CT scans in order to determine the morphological features. We measured the transverse position and depth of the trochlear groove, the transverse position of the patella, the ratio between the posterior patellar edge and the trochlear groove, the lateral patellar inclination angle, the sulcus angle, and the lateral trochlear slope. The trochlear groove lateralised a mean of 6.1 mm in the proximal aspect and 2.5 mm in the distal aspect of the trochlea, while the patella medialised a mean of 5 mm. Preoperatively the patella was lateral in relation to the trochlear groove in 13 cases, neutral in two cases, and medial in two cases. Postoperatively it was lateral in four cases, in neutral position in seven cases, and medialised in six cases, referenced to the trochlear groove. The trochlear depth increased from 0 to 5.9 mm postoperatively in the proximal aspect of the trochlea, and from 5.5 to 8.3 mm postoperatively in the distal trochlea. The lateral patellar inclination angle decreased from a mean of 21.9 degrees to a mean of 7.8 degrees . The sulcus angle decreased from a mean of 172.1 degrees to a mean of 133 degrees in the proximal trochlea and from a mean of 141.9 degrees to a mean of 121.7 degrees in the distal trochlea. The lateral trochlear slope changed from 2.8 degrees to 22.7 degrees in the proximal and from 14.9 degrees to 26.9 degrees in the distal part of the trochlea. In the CT scan patients with trochlear dysplasia demonstrated a poor depth, or even a flat or convex trochlea with a greater sulcus and lateral trochlear slope angle, a lateralised patella to the trochlear groove with poor congruency, and a greater lateral patellar inclination angle. Trochleoplasty can correct the pathological features of trochlear dysplasia by surgically creating more normal anatomy. The goal of this surgical procedure is to steepen and lateralise the trochlear groove for a better engagement of the patella.

Results of medial patellofemoral ligament reconstruction in the treatment of patellar dislocation

Purpose: The purpose of this study is to describe the technique of medial patellofemoral ligament reconstruction using autogenous hamstrings or autogenous fascia lata and report the results at a minimum 2-year follow-up. Type of Study: This study represents a case series. Patients with patellofemoral instability following patellar dislocation were restrospectively reviewed after being treated with medial patellofemoral ligament reconstruction. No concurrent control group was used. Methods: Nineteen consecutive patients underwent medial patellofemoral repair or reconstruction in the treatment of patellar instability after patellar dislocation. The reconstructions were performed using autogenous gracilis and/or semitendinosus tendons or a strip of autogenous fascia lata. Fifteen patients were available for interview, examination, and radiographic evaluation, with a mean follow-up of 31.5 months. Results: Subjectively, 10 knees had excellent results, 3 knees obtained good results, 1 knee had a fair result, and 1 knee had a poor result, for a total of 93% improvement overall. Using Fulkerson’s functional knee score, 93% had good or excellent results. The average postoperative result on Kujala’s score for anterior knee symptoms was 88 (range, 80-100). The Tegner activity level averaged 6.8 preinjury and 6.7 postoperatively. Radiographic evaluation showed significant improvements in the congruence angle by an average of 20° (P =.0006), and in the lateral patellofemoral angle by an average of 10° (P =.0003). Conclusions: Surgical reconstruction or repair of the medial patellofemoral ligament provides favorable results for the treatment of recurrent patellofemoral dislocations with regard to radiographic findings, patient satisfaction, and functional outcome.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 3 (March), 2001: pp 298–306