Corrección de la altura patelar en inestabilidad rotuliana / Correction of patellar height in patellofemoral instability

El manejo de la inestabilidad patelofemoral se basa en una adecuada evaluación de alteraciones anatómicas predisponentes. Patela alta es una de las causas más importantes de inestabilidad objetiva. La alteración biomecánica que ésta produce puede conducir a luxación patelar recurrente, dolor y cambios degenerativos focales. El examen físico es fundamental en la toma de decisiones. La evaluación imagenológica ha evolucionado desde métodos basados en radiografía hacia mediciones en resonancia magnética, que permiten una orientación más acabada de la relación existente entre la rótula y la tróclea femoral. El tratamiento se fundamenta en la corrección selectiva de los factores causales, donde la osteotomía de descenso de la tuberosidad anterior de la tibia y la reconstrucción del ligamento patelofemoral medial son herramientas que deben considerarse racionalmente. Este artículo realiza una revisión de la literatura, otorgando los fundamentos quirúrgicos que explican la importancia del tratamiento específico de patela alta en inestabilidad rotuliana.

Patellofemoral instability management is based on a thorough evaluation of predisposing anatomical factors. Patella alta is one of the utmost causes of objective instability. As a result, biomechanical disturbance can lead to recurrent patellar instability, pain, and focal degenerative changes. Physical examination is paramount in decision making. Imaging evaluation has evolved from X-rays based methods to magnetic resonance measurements, which allows a more accurate assessment of the patellotrochlear relationship. Treatment is based on a selective risk factors correction, where tibial tubercle distalization osteotomy and medial patellofemoral ligament reconstruction must be considered altogether. This article reviews the surgical rationale of patella alta treatment in patellofemoral instability.

Combined operation involving tibial tubercle distalization for recurrent patellar dislocation with patella alta / 中国修复重建外科杂志

Objective: To explore the clinical effects of combined operation involving tibial tubercle distalization for the recurrent patellar dislocation with patella alta. Methods: Between April 2010 and May 2016, 14 cases of recurrent patellar dislocation with patella alta were treated with combined operation involving tibial tubercle distalization. There were 5 males and 9 females with an average age of 18.5 years (range, 13-26 years). The left knee was involved in 9 cases and the right knee in 5 cases. The patella had dislocated 3.3 times on average (range, 2-5 times). The interval between the first dislocation and admission was 19.7 months on average (range, 4-60 months), and the main symptoms were knee pain and limited knee movement. Preoperative X-ray films, CT, and MRI examinations of knee joint showed that the epiphyseal plate closed in all patients. Of all patients, 3 patients had avulsion fracture of the inner edge of patella, and 2 patients had free body in articular cavity. The tibial tuberosity-trochlear groove (TT-TG) distance, patellar-trochlear-groove distance, Caton-Deschamps index, knee range of motion (ROM), Lysholm score, International Knee Documentation Committee (IKDC) score, Kujala score, and Tegner score were compared pre- and post-operation. Results: All patients had primary wound healing. All patients were followed up 24-72 months with an average of 34.6 months. X-ray film and CT examination showed that the patellar dislocation was corrected and the osteotomy of the tibial tubercle healed with an average healing time of 3.8 months (range, 3-5 month). At 1 day and 1 year after operation, the TT-TG distance, patellar-trochlear-groove distance, and Caton-Deschamps index showed significant differences when compared with preoperative values ( P0.05). At the 1 year and 2 years after operation, the knee ROM, Lysholm score, IKDC score, Kujala score, and Tegner score showed significant differences when compared with preoperative values ( P0.05). Conclusion: Combined operation involving tibial tubercle distalization is a safe and reliable method, which has satisfactory short-term effectiveness for the recurrent patellar dislocation with patella alta.

Total knee arthroplasty in treatment of severe osteoarthritis with patella alta / 临床外科杂志

Objective To study the therapeutic effect of total knee arthroplasty(TKA)in treat-ment of severe osteoarthritis with patella alta.Methods TKA was performed on 13 patients of severe os-teoarthritis with patella alta,to adjust the relative position of the patella by changing the height of the plat-form line in the operation,and measure the length of the perpendicular line from the lowest point of the pa-tella joint surface to the tibial platform line before and after knee replacement,calculate and compare the ratio of the length to the joint surface of the patella(BP index).In addition,the score of the knee joint was evaluated by American special surgery hospital knee joint scoring system(HSS)at preoperative and post-operative three months.Results All the patients'incision got primary healing who were followed up with-out other complications.The BP index and the HSS score was statistically significant before and after sur-gery(P<0.05).Conclusion Total knee arthroplasty can be used to treat severe osteoarthritis with high patella by adjusting the relative height of the patella and correcting the limb alignment,to improve the function of knee joint and the quality of life.

Clinics in diagnostic imaging (185)

A 20-year-old National Serviceman presented with left knee pain and swelling after training for his physical fitness test. Lateral knee radiography and magnetic resonance (MR) imaging showed patellar tendon-lateral femoral condyle friction syndrome (PT-LFCFS), on a background of patella alta and patellar malalignment. The patient was treated non-operatively with a course of physiotherapy and given advice on rest and activity modification. PT-LFCFS is a less well-recognised but important cause of anterior knee pain and represents an entity in a spectrum of disorders related to patellofemoral instability. We herein discuss the MR imaging findings specific to and associated with this condition, as well as briefly describing treatment options. In addition, we showcase a range of commonly encountered abnormalities that affect the infrapatellar fat pad and briefly discuss their specific MR imaging findings.

Clincical efficacy of medial patellofemoral ligament reconstruction combined with tibial tuberosity osteotomy in treatment of recurrent patellar dislocation associated with patella alta / 中华创伤杂志

Objective To compare the efficacy of tibial tuberosity osteotomy (TTO) combined with medial patellofemoral ligament reconstruction (MPFLR) with simple TTO in treatment of recurrent patella dislocation associated with patella alta.Methods From July 2010 to December 2015,50 patients with recurrent patella dislocation and patella alta were included in this study.There were 15 males and 35 females with an average age of 20.6 years.These patients received surgical treatment and their clinical data were collected and retrospectively analyzed by case-control study.According to surgical methods,patients were divided into TTO group (32 cases) and MPFLR + TTO group (18 cases).The differences between preoperative status and postoperative status were evaluated by knee function scores including Tegner,international knee documentation committee (IKDC),Kujala scores,knee injury and osteoarthritis outcome score (KOOS).Patellar stability was checked at the last follow-up visit.Results The TTO group and MPFLR + TTO group were followed up for (50.9 ± 17.8) months and (22.3± 10.1)months,respectively.Two patients occurred recurrent dislocation in TTO group,who showed positive in both extrapolation test and extrapolation apprehension test at 0°flexions of knee.All patients in MPFLR + TTO group did not occur recurrent dislocation,who showed negative in both extrapolation test and extrapolation apprehension test at 0° flexions of knee.There was no significant difference between preoperative and postoperative results in TTO group in Tegner score (P ＞ 0.05),KOOS scores in pain and daily life activities subdomains (P ＞ 0.05),while differences in the rest of scores were statistically significant (P ＜ 0.05).Compared with TFO group,the differences of all scores were statistically significant (P ＜ 0.05) and KOOS scores in the pain and daily life activities subdomains were significantly improved postoperatively in MPFLR + TTO group P ＜0.05).Conclusions For patients with recurrent patellar dislocation associated with patella alta,both surgical methods are found to be effective.Postoperative improvements in pain and daily life activities are less obvious in TTO.While postoperative improvements in pain and daily life activities in MPFLR + TTO are superior to those of TTO.

Measurement and evaluation of anatomic risk factors for recurrent patellar instability by MRI / 实用放射学杂志

Objective To identify related anatomical parameters and the strongest risk predictor leading to patients with recurrent patellar instability.Methods 52 young patients with recurrent patellar instability that failed of conservative treatment were retrospec-tively evaluated by MRI.Measurements included parameters of patellar tracking,which was characterized by bisect offset index (BSO),trochlear congruence angle (CA)and patellar lateral tilt (PTA),and anatomical parameters of patellofemoral joint,which were characterized by the sulcus angle (SA),lateral trochlear inclination (LTI),trochlear facet asymmetry,trochlear depth,Insall-Salvati Ratio (ISR),Caton-Deschamps index (C-D)and tibial tuberosity-trochlear groove (TT-TG)distance.The collection data were analyzed including the Pearson's correlation and multiple stepwise regression analysis.Results The patellofemoral joint ma-lalignment was significantly correlated with LTI,TT-TG distance and ISR,but not or partly with the trochlear depth,SA,trochlear facet asymmetry and C-D.Linear regression models including LTI,TT-TG distance and ISR explained 0.58,0.47 and 0.43 of the va-riance in BSO,CA and PTA,respectively (P<0.001).And the standardized beta coefficient was largest for LTI,then were TT-TG distance and ISR.Conclusion At full extension of the knee,anatomical related factors measured on MRI explain some degree of re-current lateral patella shift and tilt,the strongest predictor among anatomical related factors that could lead to maltracking is LTI, and then are TT-TG distance and ISR.

Anterior Knee Pain in Patients with Cerebral Palsy

BACKGROUND: The aim of this study was to identify the risk factors for anterior knee pain in patients with cerebral palsy. METHODS: This prospective study investigated the risk factors for anterior knee pain in 127 ambulatory patients with spastic cerebral palsy in terms of walking pain, resting pain, and provocative pain. Demographic data analysis and physical examination for measuring the knee flexion contracture and unilateral and bilateral popliteal angles were performed. Patellar height was measured on radiographs, and patella alta was identified. The risk factors for anterior knee pain were analyzed using multivariate analysis with a generalized estimating equation. RESULTS: Seventy-seven patients were found to have patella alta based on the radiographic measurements (60.6%). Overall, sixteen patients (12.6%) had either unilateral or bilateral anterior knee pain. Of these, 6 patients showed a visual analogue scale (VAS) 7. Age was found to be a significant risk factor for walking pain and resting pain with odds ratios (ORs) of 1.08 (95% confidence interval [CI], 1.02 to 1.14) and 1.09 (95% CI, 1.03 to 1.15), respectively. In the multivariate analysis, knee flexion contracture was a significant protective factor with an OR of 0.92 (95% CI, 0.85 to 0.98). CONCLUSIONS: Approximately 12.6% of ambulatory patients with spastic cerebral palsy were found to have anterior knee pain in our hospital-based cohort study. Age was found to be a significant risk factor for anterior knee pain while walking and resting.

EXPERIMENTAL STUDY OF DEGENERATION OF PATELLAR CARTILAGE CAUSED BY ELONGATION OF PATELLAR LIGAMENT IN RABBITS / 中国运动医学杂志

Twenty-four rabbits' patellar ligaments were elongated 3 mm surgically, which decreased the pressure of the patellar articular cartilage. The pathological changes of cartilage and subchondral bone of the patellar were examined by light microscope and scanning electron microscope sequentially. 4 weeks after the surgery, proliferation of blood vessels in the subchondral bone and their invasion into the calcafied cartilage were seen, without abnormality in the patellar articular cartilage. After 8 weeks, irregularity of the tide mark and cartilage cells column, and peripheral part of the cartilage showed cluster formation. After 12 weeks, degeneration extended to the superficial layer of the cartilage, producing blister formation, fibrillation and a decrease in the thickness of the cartilage. These findings were similar to the histological changes of chondromalacia patellae. It was further suggested that decrease of pressure on the cartilage could be considered to be one of the causes for articular cartilage injury, and patella alta be correlated with chondromalacia of the patella.