Modified Langenskiöld Procedure for Congenital Patella Dislocations in Pediatric Patients

Background: Great difficulty and more failures were the descriptions of the treatment of congenital patella dislocation in pediatric patients. This study aims to evaluate the outcomes of patients with congenital patellar dislocations treated with the modified Langenskiöld procedure. Methods: The medical records of 16 knees in 11 patients with a diagnosis of congenital patella dislocation were collected from September 2016 to March 2019. They were treated with the modified Langenskiöld procedure. The mean follow-up period was 37.8 months. The outcome measures were the Lysholm score, Kujala score, patellar stability, and knee range of motion. Results: Eleven patients, namely, eight girls and three boys, with 16 knees were enrolled. The mean age at the time of operation was 3.1 years. The post-operative mean Lysholm score was 94.8 (SD 5.1; 87–100), whereas the Kujala score was 95 (SD 5.9; 86–100). There were no recurrent dislocations, and all patients had full extension postoperatively. Conclusion: The modified Langenskiöld procedure is a promising solution for the treatment of congenital patella dislocations. Level of evidence: Level IV; Case Series; Treatment Study

Ablation of the FACIT collagen XII disturbs musculoskeletal ECM organization and causes patella dislocation and myopathy

Collagen XII, belonging to the fibril-associated collagens with interrupted triple helix (FACIT) family, assembles from three identical α-chains encoded by the COL12A1 gene. The trimeric molecule consists of three N-terminal noncollagenous NC3 domains joined by disulfide bonds followed by a short interrupted collagen triple helix at the C-terminus. Collagen XII is expressed widely in the musculoskeletal system and mutations in the COL12A1 gene cause an Ehlers-Danlos/myopathy overlap syndrome, which is associated with skeletal abnormalities and muscle weakness. Our study defines the role of collagen XII in patella development using the Col12a1-/- mouse model. Deficiency in Col12a1 expression causes malformed facies patellaris femoris grooves at an early stage, which leads to patella subluxation and growth retardation. Due to the patella subluxation, more muscle fibers with centralized nuclei occur in the quadriceps than in the gastrocnemius muscles indicating a local effect. To further understand the role of collagen XII in the skeletal tissues single cell RNAseq (scRNA-seq) was performed. Comparison of the gene expression in the tenocyte cell sub-population of wild type and Col12a1-/- mice showed that several matrix genes are altered. Finally, we reinvestigated collagen XII deficient patients and observed a patella instability.

Anatomical Characteristics and Potential Gene Mutation Sites of a Familial Recurrent Patellar Dislocation

Background Recurrent patellar dislocation is the result of anatomical alignment and imbalance of restraint of bone and soft tissue. To investigate the anatomical characteristics of the knee joint in a family of patients with recurrent patella dislocation, and to screen the possible pathogenic genes in this family by whole exon sequencing in 4 patients and 4 healthy subjects, so as to provide theoretical basis for the pathogenesis of this disease. Methods The data related to patella dislocation were measured by imaging data. The peripheral blood DNA of related family members was extracted for full exon sequencing, and then the sequencing results were compared with the human database. By filtering out synonymous mutations and high-frequency mutations, and then integrating single nucleotide non-synonymous mutations of family members, disease-causing genes were found. Results All patients in this family have different degree of abnormal knee anatomy, which is closely related to patella dislocation. The sequencing results of patients and normal persons in this patella dislocation family were compared and analyzed, and the data were filtered through multiple biological databases. Find HOXB9(NM_024017.4:p.Glu135Gly/c.404A>G),COL1A1(NM_000088.3:p.Ala1256 Thr/c.3766G>A),GNPAT(NM_014236.3:p.Asp519Gly/c1556A>G),NANS(NM_018946.3:p.Glu68Asp/c.204G>C),SLC26A2(NM_000112.3:p.Thr689Ser/c.2065A>T) are not synonymous mutations (MISSENSE). Through Sanger sequencing, HOXB9 and SLC26A2 genes were found to be the pathogenic genes of this family with recurrent patella dislocation. Conclusions The anatomical structure of the knee joint of patients with recurrent patellar dislocation in this family is obviously abnormal. HOXB9 mutation may be the high frequency pathogenic gene of recurrent patella dislocation in this family, while COL1A1, GNPAT, NAans, SLC26A2 gene may be the sporadical pathogenic gene.

Dynamic Medial Patellofemoral Ligament Reconstruction in Patellar Instability: A Surgical Technique

Background: Patella instability with recurrent dislocations is a result of various pathologies, for example, patella alta, trochlea dysplasia or medial patellofemoral ligament (MPFL) rupture. The recurrent dislocation rate of conservatively treated chronic patellar instability is high; therefore, it is recommended to manage it surgically. This video presents a new operative approach to stabilize the patella in a dynamic MPFL reconstruction, which addresses the most common complications occurring in static reconstructions: malpositioning and overtensioning the graft. Indications: Surgical indications for the new dynamic procedure mirror the indications for static MPFL reconstruction. This is MPFL insufficiency (patella instability in the first 30° of knee flexion), which is most frequently seen in recurrent lateral patella dislocations. Moreover in very rare cases of first patella dislocation with a patellar instability severity score equal or higher than 4. Technique Description: The dynamic MPFL reconstruction consists of 3 steps: First, detaching and mobilizing the gracilis muscle at its anatomical insertion. Second, redirecting the freed gracilis muscle to its new patellar insertion. Third, reinserting the gracilis muscle at the patella. Results: The dynamic MPFL reconstruction has the advantage of lesser risk of overtensioning and malpositioning the graft. The insertion point of the MPFL surrogate is easier to locate, and the patella is dynamically stabilized through reflectory gracilis muscle contraction. Compared with the static reconstruction, only one instead of 3 holes have to be drilled and only 1 interference screw has to be placed, thus shortening the surgery time. From a theoretical biomechanical perspective, the dynamic tensioning is superior to the static procedure. The few accomplished studies published so far by Becher et al and Ostermeier et al show good or better functional results (Kujala, Lysholm, Tegner scores) with the dynamic MPFL reconstruction, yet higher evidence studies need to be performed. Conclusion: Dynamic MPFL reconstruction appears to be a simpler and more effective surgical technique for MPFL reconstruction. Because of its novelty, high evidence studies assessing long-term therapeutical outcomes are still lacking and need to be conducted in order to compare it conclusively with the static procedure.

A Study into the Pawprints of Urban Dogs

The aim of the article is to present a comprehensive study on specific paw parameters and features, movement peculiarities, leg injuries, hairiness, etc. of dogs that lived in the city of Vilnius and its surroundings and left their marks on clay ware made by local craftsmen. The study was based on 238 clay objects found in Vilnius and dating from the late thirteenth to the eighteenth century. Dogs were found to leave the highest number of pawprints on bricks (90.8%), with significantly lower numbers on floor tiles (8%) and roof tiles (1.2%). The apparent increase in the number of traces is recorded from approximately the fifteenth century due to the steady increase in the quantity of clay products and the accessibility of the production environment to domestic animals. More than 450 dog pawprints in clay were examined using a trasology technique. Most frequently, one, two, or three traces were found on an artefact, while four, five, or six traces on one object were much less frequent. The analysis of trace features showed that 179 of the traces were those of the forepaws and 112 of the hind paws. The assessment of the deformation of the clay articles during firing and the comparison of the data obtained with the parameters of the paws of current breeds of dogs suggest that about 2% of the pawprints were left by small or young dogs. Mediumsized dogs left 70.5% of the traces, 25.7% belonged to dogs resembling current breeds of Doberman or Labrador retriever, 4.7% dogs similar to Borzoi or German shepherd, and 0.9% to Akita or Bobtail. An additional comparison of the pawprints with those of the present-day Lithuanian hounds showed that this type of dog could have left about 22% of the total number of the paw prints studied. It can be concluded that the results of the tracing studies revealed a significantly broader picture than the zooarchaeological material. Pawprint studies show that 25% of the dogs in the city of Vilnius during the period in question were long-haired and 75% were short-haired. The recorded paw pathologies provided information on various nail and toe injuries, tendon pathologies, and one possible case of patella dislocation. Meanwhile, the analysis of the dogs’ speed of movement suggests that at least some of the dogs in Vilnius between the late thirteenth and the eighteenth century were not tied and moved freely in the environment of the craftsmen who manufactured clay ware. In summary, the preliminary results of the pawprint analysis make a significant contribution to the broader knowledge of the history of dogs and provide unique data on urban dogs, which are scarcely recorded in written and zooarchaeological sources.

Persistent J-Sign Following Distalization with Correction of Patellar Height: A Descriptive study reviewing anatomic factors (195)

Objectives: The anatomic factors associated with a J-sign (patella dislocation in extension) are debated and likely multi-factorial. With trochlear shape and patella height playing a role. The goal of distalization of the tibial tubercle (dTTO) is normalization of patella height to improve patellar stabilization by earlier trochlear groove engagement. dTTO is felt to diminish or remove the J-sign by ‘by-passing’ the supra-trochlear bump, thus avoiding the need for a trochleoplasty in addition to a dTTO. The objective is to determine if a persistent J-sign after surgical patellar stabilization and adequate patellar height restoration is due to additional anatomic variances that were not surgically addressed. Methods: A retrospective chart review of 89 consecutive patients who were treated by a single surgeon for recurrent lateral patella dislocation with medial patellofemoral ligament reconstruction (MPFL-R) and dTTO was undertaken. 63 patients were identified with a pre-operative J-sign and formed the study sample. 40 of these patients had no J-sign post-operatively and 23 patients had a persistent postoperative J-sign. All patients had radiographic measurements made for patella alta (caton-deschamps index [CD]), and magnetic resonance imaging measurements of trochlear depth, sulcus angle, as well as the individual components for measuring trochlear depth (medial, central, and lateral height). Results: The average age of patients at time of surgery was 21 years old (range,13-45). Females were 74% of the population. Average BMI was 26 (17-44) and follow-up averaged 16 months. Table 1 demonstrates the between group differences for the statistically significant variables. These included trochlear depth, and lateral-central difference (via components of trochlear depth calculation) (fig 1). If the patient had lateral condylar height < medial condylar height, a J -sign persisted (4 patients). When the post op C/D >/= 1.2, 5/6 (83%) patients had a persistent j-sign. There were 5 re-dislocations in this population: 2/23 (13%) with a persistent J-sign and 3/40 (8%) without. The KOOS was available for all patients at a minimum of 3 months (Table 2). There was no statistically significant domain that demonstrated a difference between the 2 groups. In both groups, the domains with the lowest scores were quality of life, sports, and symptoms. Conclusions: Dysplastic trochlea that have a small lateral-central difference (<2mm), a shallower trochlear depth, or a lateral condylar height less than the medial condylar height, are more likely to result in a persistent J-sign. In the setting of these dysplastic trochleas, consideration should be given to address trochlear anatomy at the same time as addressing patella height normalization.In the presence of a J-sign, patella height should be normalized to CD < 1.1 to reduce the likelihood of a persistent J-Sign. Post-Op KOOS scores suggest the persistent J-sign does not impact the functional recovery in these patients. In our cohort, there was no increased risk of re-dislocation with a persistent J-Sign.