Patella alta in patellofemoral instability

In a retrospective study of 90 realignment procedures for patellar instability, a high percentage of patella alta was diagnosed based upon the preoperative radiographs: 53% or 48 knees. The LP-LT index, described by Insall and Salvati, averaged 0.80 for this group of patients. Post-operative measurements of this index showed a definite correction of the craniocaudal position of the patella, with a mean increase of 0.10 (0.80 to 0.90). In evaluating the severity of the eliciting trauma, it is suggested that the alta position makes the patella more prone to instability: only 14.5% of the alta knees (n = 48) sustained a significant trauma versus 28.5% in the non-alta population (n = 42). The altaposition, however, had no influence on the final outcome, (at a mean follow-up time of 57 months), after a latero-medial realignment procedure, using a proximal or a combined proximal and distal procedure.     

Medial patellofemoral ligament reconstruction for recurrent patellar instability

The purpose of this study was to determine the value of reconstruction of the medial patellofemoral ligament (MPFL) in the treatment of recurrent patellar dislocation and subluxation. We retrospectively reviewed 40 randomised patients with recurrent patellar dislocation or subluxation, who had undergone realignment surgery from July 1999 to December 2001. Group E consisted of 20 patients who had undergone an Elmslie-Trillat procedure. In Group M, also consisting of 20 patients, the Elmslie-Trillat procedure was combined with reconstruction of the MPFL. Pre and postoperative data were collected and compared. At follow-up after 2 years, the apprehension sign remained positive in 6 knees of Group E, but in none of Group M. On a stress skyline radiograph, stability was significantly better in Group M than in Group E. Based on these findings, it appears that reconstruction of the MPFL is a useful addition to the treatment of recurrent patellar dislocation and subluxation.     

Reconstruction of medial patellofemoral ligament for chronic patellar instability

Background:

Disruption of the capsule, medial patellar retinaculum, and/or vastus medialis obliqus has been associated with recurrent patellar instability. Biomechanical studies have shown that the medial patellofemoral ligament (MPFL) is the main restraint against lateral patella displacement and reconstruction of the MPFL has become an accepted surgical technique to restore patellofemoral stability in patients having recurrent patellar dislocation. We report a prospective series of patients of chronic patellar instability treated by reconstruction of medial patellofemoral ligament.

Materials and Methods:

Twelve patients (15 knees) with recurrent dislocation of patella, were operated between January 2006 and December 2008. All patients had generalised ligament laxity with none had severe grade of patella alta or trochlear dysplasia. The MPFL was reconstructed with doubled semitendinosus tendon. Patients were followed up with subjective criteria, patellar inclination angle, and Kujala score.

Results:

The mean duration of followup after the operative procedures was an average of 42 months (range 24–60 months) 10 knees showed excellent results, 3 knees gave good results, and 2 knees had a fair result. The average patellar inclination angle decreased from 34.3° to 18.6°. The average preoperative Kujala functional score was 44.8 and the average postoperative score was 91.9.

Conclusion:

MPFL reconstruction using the semitendinosus tendon gives good results in patients with chronic patellar instability without predisposing factors like severe patella alta and high-grade trochlear dysplasia, and for revision cases.     

A prospective evaluation of trochleoplasty for the treatment of patellofemoral dislocation and instability

Trochlear dysplasia is a developmental condition characterised by an abnormally flat or dome-shaped trochlea and is an important contributory factor to patellofemoral instability and recurrent dislocation. We studied prospectively a series of 54 consecutive patients (59 knees) with patellofemoral instability secondary to trochlear dysplasia, who were treated by a trochleoplasty by a single surgeon between June 2002 and June 2007. Pre- and post-operative scores were assessed by the patients and a satisfaction questionnaire was completed. Of the 54 patients (59 knees) in the series, 39 (44 knees) were female and 15 (15 knees) were male. Their mean age at surgery was 21 years and 6 months (14 years 4 months to 33 years 11 months). In 40 patients (42 knees) the mean follow-up was for 24 months (12 to 58). One patient was unable to attend for follow-up. An analysis of the results of those patients followed up for at least 12 months showed a statistically significant improvement in outcome (p < 0.001 for all scores). Overall, 50 patients (92.6%) were satisfied with the outcome of their procedure. The early results of trochleoplasty are encouraging in this challenging group of patients.     

Assessment and management of chronic patellofemoral instability

Chronic patellofemoral instability can be a disabling condition. Management of patients with this condition has improved owing to our increased knowledge of the functional anatomy of the patellofemoral joint. Accurate assessment of the underlying pathology in the unstable joint enables the formulation of appropriate treatment. The surgical technique employed in patients for whom non-operative management has failed should address the diagnosed abnormality. We have reviewed the literature on the stabilising features of the patellofemoral joint, the recommended investigations and the appropriate forms of treatment.     

Treatment of patellofemoral instability in Down's syndrome

In a retrospective review, 16 patients with Down's syndrome with the chief complaint of patellofemoral joint dislocations or subluxations were studied. Twenty-six dislocatable or dislocated patellae were seen in these 16 patients. The degree of patellofemoral instability was not correlated with either the ambulatory status or the form of treatment (operative/nonoperative). An increasing degree of patellofemoral instability was correlated strongly with the presence of deformities. Nonoperative treatment either maintained or improved the ambulatory status in 67% of these knees with either fair or good ambulation, whereas 80% of the knees with poor ambulation did not improve. Operative treatment resulted in good ambulatory ability in 86% of the knees with fair or poor preoperative ambulatory status, but did not effectively correct deformities that subsequently resulted in degenerative arthritis.     

Intraoperative evaluation of DRUJ instability through dorsal stress radiography in distal radius fractures

IntroductionCertain type of injury of the triangular fibrocartilage complex associated with distal radius fracture can result in distal radioulnar joint instability (DRUJ). Untreated DRUJ instability may lead to poor result in the treatment of acute distal radius fractures. The aim of this study was to evaluate DRUJ instability in distal radius fractures through dorsal stress radiography comparing the affected and unaffected wrists intraoperatively.Materials and methods49 patients with a distal radius fracture who were operatively treated with a volar locking plate were included. Dorsal stress radiography was used to evaluate both affected and unaffected wrists peri-operatively to detect DRUJ instability. Under general anesthesia, a dorsal stress test was performed on the unaffected wrist. Additionally, after fixation of the affected wrist, a dorsal stress test was performed. The ulnar translation ratio (UTR) was measured through the dorsal stress radiograph. Arthroscopic examination was performed on all affected wrists according to Palmer's and Atzei classification.ResultsThe UTR of the affected wrist and the TFCC injury Palmer-type IB tendency were positively correlated (odds ratio: 1.18, p-value: 0.002). Additionally, as the UTR difference between the affected and unaffected wrists enlarged, it revealed a significant DRUJ instability tendency due to Palmer-type IB TFCC injury (p-value: 0.000006, Wilcoxon rank-sum test).ConclusionsDorsal stress radiography is a reliable, simple procedure to evaluate DRUJ instability intraoperatively. UTR value from dorsal stress radiography could be useful for evaluating DRUJ instability associated with distal radius fracture.     

YouTube provides insufficient information on patellofemoral instability

Objective:Videos uploaded to YouTube do not go through a review process, and therefore, videos related to patellofemoral instability may have little educational value. The purpose of this study was to assess the educational quality of YouTube videos regarding patellofemoral instability.Methods:A standard search was performed on the YouTube database using the following terms: “unstable kneecap,” “patellar instability,” “patellofemoral instability,” “kneecap dislocation,” and “patellar dislocation,” and the top 50 videos based on the “relevance” assignment of the YouTube algorithm were included for analysis. The properties, content, and source of each video were recorded. The educational quality of videos was analyzed according to scores obtained using DISCERN, the criteria of Journal of the American Medical Association, Global Quality Score, and Patellofemoral Instability Specific Score, and the quality of the videos was evaluated according to the groupings of these scoring systems.Results:A total of 250 videos were identified, of which 89 were included in the study for analysis. The mean video duration was 11.72 ± 22.03 minutes. The median number of views was 4516.5 (range, 3-6 044 971). The content of the videos was disease-specific in 60%, 20% were related to surgical technique or approach, and 14.1% were exercise videos. Most of the videos were uploaded by physicians (33.7%). The Global Quality Score and DISCERN scores were significantly correlated with video duration. The Patellofemoral Instability Specific Score was significantly correlated with video duration, number of views, view rate, likes, and Video Power Index. According to the DISCERN classification, 69.9% of the videos were very insufficient or insufficient. According to the Patellofemoral Instability Specific Score, 65.2% of videos were evaluated as very low or low. According to the Global Quality Score, 60.7% of videos were rated as poor quality.Conclusion:The quality of YouTube videos about Patellofemoral instability is insufficient. It was found that viewers tend to watch short and low-quality videos.     

Medial patellofemoral ligament reconstruction in patellar instability

Background:

Medial patellofemoral ligament (MPFL) is one of the major static medial stabilising structures of the patella. MPFL is most often damaged in patients with patellar instability. Reconstruction of MPFL is becoming a common surgical procedure in treating patellar instability. We hypothesised that MPFL reconstruction was adequate to treat patients with patellar instability if the tibial tubercle and the centre of the trochlear groove (TT-TG) value was less than 20 mm and without a dysplastic trochlea.

Materials and Methods:

30 patients matching our inclusion criteria and operated between April 2009 and May 2011 were included in the study. MPFL reconstruction was performed using gracilis tendon fixed with endobutton on the patellar side and bio absorbable interference screw or staple on the femoral side. Patients were followed up with subjective criteria, Kujala score and Lysholm score.

Results:

The mean duration of followup was 25 months (range 14-38 months). The mean preoperative Kujala score was 47.5 and Lysholm score was 44.7. The mean postoperative Kujala score was 87 and Lysholm score was 88.06. None of the patients had redislocation.

Conclusion:

MPFL reconstruction using gracilis tendon gives excellent results in patients with patellar instability with no redislocations. Some patients may have persistence of apprehension.     

Reconstruction of the medial patellofemoral ligament for treatment of patellar instability

Background and purpose Postoperative pain is often severe after total knee arthroplasty (TKA). We investigated the efficacy of the local infiltration analgesia (LIA) technique, both intraoperatively and postoperatively.

Methods 48 patients undergoing TKA were randomized into 2 groups in a double-blind study. In group A, 400 mg ropivacaine, 30 mg ketorolac, and 0.5 mg epinephrine were infiltrated periarticularly during operation. In group P, no injections were given. 21 h postoperatively, 200 mg ropivacaine, 30 mg ketorolac, and 0.1 mg epinephrine were injected intraarticularly in group A, and the same volume of saline was injected in group P. All patients were followed up for 3 months.

Results Median morphine consumption was lower in group A during the first 48 h: 18 (1–74) mg vs. 87 (36–160) mg in group P. Postoperative pain was lower at rest in group A during the first 27 h, and on movement during the first 48 h, except at 21 h. Time to fulfillment of discharge criteria was shorter in group A than in group P: 3 (1–7) vs. 5 (2–8) days. Patient satisfaction was higher in group A than in group P on days 1 and 7. The unbound venous blood concentration of ropivacaine was below systemic toxic blood concentrations.

Interpretation The local infiltration analgesia (LIA) technique provides excellent pain relief and lower morphine consumption following TKA, resulting in shorter time to home readiness and higher patient satisfaction. There were few side effects and systemic LA concentrations were low.     

Medial reefing versus medial patellofemoral ligament reconstruction for patellar instability

The standard surgical treatment for patellar instability has been lateral release and medial reefing proximally, with a Roux-Goldthwaite tendon transfer distally. More recently, reconstruction of the medial patellofemoral ligament (MPFL) has become popular. The aim of this study was to determine whether MPFL reconstruction improved the functional outcomes over patients treated with medial reefing. A group of 28 knees in 25 patients treated with a MPFL reconstruction were identified and matched for age and gender with 28 operated knees in 27 patients treated with a medial reefing. Clinical assessment included pre-operative and 1 year Kujala scores. Radiological assessment used the Dejour protocol. The two groups were comparable with respect to gender, age, pre-operative Kujala score, type of trochlear dysplasia, tibial tubercle–trochlear groove distance and patellar tilt angle. It was concluded that although there was better patellar tracking at 1 year with an MPFL reconstruction compared to medial reefing, there was no significant functional improvement as measured by the Kujala score.     

Medial patellofemoral ligament reconstruction with gracilis autograft for patellar instability

We describe a technique for patellar stabilization by reconstruction of the medial patellofemoral ligament with the gracilis tendon. The tendon is anchored posteriorly on the soft tissue of the medial femoral epicondyle and anteriorly on the medial border of the patella. The plasty is completed by suture of the medial patellar wing. Inferior or medial transposition of the tibial tubercle may be associated. We have used this technique since 1995 for 145 knees with patellar instability. The small incisions have the advantages of minimally invasive surgery, particularly for the postoperative period and the cosmetic effect.     

Compression-traction radiography of lumbar segmental instability

Compression-traction radiography was used to assess movements in the sagittal plane of the lumbosacral joint in a control group of asymptomatic normal individuals and in a patient group with a symptomatic lytic spondylolisthesis. Sagittal translatory movements were found in both groups, but the amount of displacement was significantly larger (P less than 0.001) in the patient group as compared with the controls. The average displacement in the patient group, using a relative measurement technique, was 5.2%, ranging from 0.2 to 15.4%; and the corresponding values in the controls resulted in a mean of 0.8% and a range of -2.3% to 3.6%. Eighteen of the 29 patients (62%) exhibited translations of the lytic vertebra exceeding the largest displacement (greater than 3.6%) detected in the control group. The translatory movements in the patients were composed of a predominant anterior displacement in the compression view and a smaller posterior movement in the traction view. Analysis of sagittal rotation, ie, angulatory movements in the L5-S1 segment, resulted in no significant difference between the two groups. Compression-traction radiography may detect pathologic translatory movements, indicative of lumbar segmental instability.     

The role of trochlear dysplasia in patellofemoral instability

Trochlear dysplasia is characterized by abnormal trochlear morphology and a shallow groove. It is associated with recurrent patellar dislocation, but it is unclear whether the dysplasia is congenital, the result of lateral tracking and chronic instability, or caused by a combination of factors. Lateral radiographs elucidate the crossing sign and characteristic trochlear prominence. Recurrent patellofemoral instability is multifactorial, and each component must be considered in determining treatment. Managing other factors associated with recurrent instability may compensate for a deficient trochlea and provide stability. Medial patellofemoral ligament reconstruction is recommended for patellofemoral instability in the presence of trochlear dysplasia in patients without patella alta or increased tibial tubercle-trochlear groove distance. Trochleoplasty should be reserved for severe dysplasia in which patellofemoral stability cannot otherwise be obtained.     

Distal alignment procedures for patellofemoral instability: comprehensive review of the literature

Patellofemoral disorders are a common cause of complaint in adolescent patients. Several distal realignment procedures performed in isolation or combination with proximal alignment have been described. To clarify the role of distal alignment for patellofemoral instability, a systematic review of the literature was conducted. Two independent reviewers accessed the following databases: PubMed, Medline, CINAHL, Cochrane, EMBASE and Google Scholar. A total of 1478 patients with a mean age of 22.78 years were included. The mean follow-up was 86.53 months. The average Kujala score improved from 57.66 to 82.73. The average Lysholm score improved from 63.25 to 87.87, and the average Tegner score from 3 to 4.16. VAS score improved from an average 8 to 2.56. We account a total of 46 major complications, 45 minor complications and 95 recurrences. The risk of a recurrence is 6.42%. A total of 122 additional surgeries were performed during the follow-up. This systematic review of literature suggests the importance to identify the pathological background that predisposes patients for developing patellofemoral instability and its implications for the decision-making process. The optimal treatment for patellofemoral instability should be individualized to address the specific anatomical abnormalities that contribute to patellofemoral dislocations. Distal alignments are a feasible solution to restore correct patellar biomechanics and tracking, leading to an improvement of patients’ quality of life.