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Shih SSW, Kuo CL, Lee DYH. MPFL reconstruction corrects patella alta: a cohort study. EUROPEAN JOURNAL OF ORTHOPAEDIC SURGERY AND TRAUMATOLOGY 2021; 32:883-889. [PMID: 34159482 DOI: 10.1007/s00590-021-03056-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 06/14/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE Patella alta is an established risk factor for recurrent lateral patella dislocations. Medial patellofemoral ligament (MPFL) reconstruction has been shown to reduce patella height. Our hypothesis is that isolated MPFL reconstruction corrects patella alta, thereby reducing the risk of recurrent patella dislocation. METHODS A prospective cohort study of 33 knees which underwent MPFL reconstruction for recurrent patella dislocation. The pre-operative and post-operative patella height and Kujala knee outcome scores, as well as tibial tuberosity-trochlear groove (TT-TG) distance, and the grade of trochlear dysplasia were recorded. RESULTS The mean age was 21.5 years (16-34 years). There was significant reduction in patella height in all patients (p < 0.001), a 67% normalisation of patella alta (CD ≥ 1.2) (p < 0.004), and improvement in the Kujala scores 57.1 (pre-operatively) to 94.8 (post-operatively, p < 0.0001). The recurrent dislocation rate was 3%. CONCLUSION MPFL reconstruction alone results in correction in patella alta and improvement in clinical outcomes.
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Hiemstra LA, Kerslake S, Lafave MR, Tucker A. Patella alta is reduced following MPFL reconstruction but has no effect on quality-of-life outcomes in patients with patellofemoral instability. Knee Surg Sports Traumatol Arthrosc 2021; 29:546-552. [PMID: 32274546 DOI: 10.1007/s00167-020-05977-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 03/30/2020] [Indexed: 01/17/2023]
Abstract
PURPOSE The primary purpose of this study was to determine if isolated medial patellofemoral ligament (MPFL) reconstruction for lateral patellofemoral instability altered the patellar height ratio. Secondary purposes were to use disease-specific quality-of-life scores to determine if MPFL reconstruction is as successful in patients with patella alta, compared to those without; and whether the change in the patellar height ratio after MPFL reconstruction is influenced by demographic and clinical factors. METHODS Demographic and clinical data were collected pre-operatively on 283 patients with recurrent patellofemoral instability. Pre-operative and 6-month post-operative true-lateral radiographs were assessed to determine the patellar height ratio using the Caton-Deschamps index. A Caton-Deschamps index ≥ 1.2 was defined as patella alta. Paired t tests evaluated the effect of MPFL reconstruction on the Caton-Deschamps index. Using a two-sample t test, pre- and 24-month post-operative Banff Patellofemoral Instability Instrument (BPII) scores were assessed for differences in clinical outcomes between patients with and without patella alta. Pearson (for continuous variables) and Spearman rank correlations (for binary/ordinal variables) were calculated to determine the relationship between the patellar height ratio, demographic and pathoanatomic risk factors, and pre- and post-operative BPII scores. RESULTS Pre- and post-operative true-lateral radiographs were admissible for 229/283 patients (81%) following isolated MPFL reconstruction. A statistically significant difference in the Caton-Deschamps index was evident from pre- to post-operative for the entire cohort (p < 0.001). The mean decrease in ratio was 0.03, and the effect size was 0.27, classified as small. Pre-operatively 52/229 patients (22.7%) demonstrated a Caton-Deschamps index ≥ 1.2, mean = 1.27 (SD = 0.08); post-operatively 21/229 patients (9.2%) demonstrated patella alta, mean = 1.18, (SD = 0.10), p < 0.001 (two-tailed). The mean decrease in the Caton-Deschamps index for patients with pre-operative patella alta was 0.10; the effect size was 0.82, classified as large. Pearson r correlation of patella alta to the pre- and post-operative BPII scores demonstrated no statistically significant relationship. CONCLUSION This study has demonstrated that treatment of lateral patellofemoral instability with an isolated MPFL reconstruction results in a statistically significant decrease in patellar height ratio, with the effect size being greatest in patients with higher pre-operative Caton-Deschamps indices. In patients that presented with patella alta, normalization of the patellar height ratio occurred in 31/52 (59.6%) of the cases. Pre-operative patella alta was not associated with a statistically significant difference in disease-specific BPII outcome scores at any time point. Given these findings, the utility and results of tibial tubercle distalization in patients with patella alta should be a focus of further research. Level of evidence IV.
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Why compromise the patella? Five-year follow-up results of medial patellofemoral ligament reconstruction with soft tissue patellar fixation. INTERNATIONAL ORTHOPAEDICS 2021; 45:1493-1500. [PMID: 33386924 PMCID: PMC8178154 DOI: 10.1007/s00264-020-04922-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 12/17/2020] [Indexed: 10/27/2022]
Abstract
PURPOSE This study investigates the redislocation rate and functional outcome at a minimum follow-up of five years after medial patellofemoral ligament (MPFL) reconstruction with soft tissue patellar fixation for patella instability. METHODS Patients were retrospectively identified and knees were evaluated for trochlea dysplasia according to Dejour, for presence of patella alta and for presence of cartilage lesion at surgery. At a minimum follow-up of five years, information about an incident of redislocation was obtained. Kujala, Lysholm, and Tegner questionnaires as well as range of motion were used to measure functional outcome. RESULTS Eighty-nine knees were included. Follow-up rate for redislocation was 79.8% and for functional outcome 58.4%. After a mean follow-up of 5.8 years, the redislocation rate was 5.6%. There was significant improvement of the Kujala score (68.8 to 88.2, p = 0.000) and of the Lysholm score (71.3 to 88.4, p = 0.000). Range of motion at follow-up was 149.0° (115-165). 77.5% of the knees had patella alta and 52.9% trochlear dysplasia types B, C, or D. Patellar cartilage legions were present in 54.2%. Redislocations occurred in knees with trochlear dysplasia type C in combination with patella alta. CONCLUSION MPFL reconstruction with soft tissue patellar fixation leads to significant improvement of knee function and low midterm redislocation rate. Patients with high-grade trochlear dysplasia should be considered for additional osseous correction.
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Tageldeen Mohamed M, Elsobky M, Hegazy M, Elbarbary HM, Abdelmohsen MM, Elsherbini M, Barakat AS, Diab NM. Evaluation of infrapatellar tendon plication in spastic cerebral palsy with crouch gait pattern: a pilot study. SICOT J 2020; 6:40. [PMID: 33030425 PMCID: PMC7543689 DOI: 10.1051/sicotj/2020037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/22/2020] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVE In order to substantially improve crouch pattern in cerebral palsy, the existent patella alta needs to be addressed. This pilot study evaluates the effectiveness of a previously described infrapatellar tendon plication for the treatment of patella alta in crouch gait pattern in skeletally immature spastic cerebral palsy patients. METHODS In 10 skeletally immature patients (20 knees) with spastic diplegia and crouch gait, the previously described technique by Joseph et al. for infrapatellar tendon plication was evaluated within the setting of single event multilevel surgery (SEMLS). Outcome measures included knee extension lag, Koshino's radiological index for patella alta, and the occurrence of complications. Patients were followed-up for a minimum of 12 months. RESULTS The extensor lag improved and was statistically significant in all cases of the study with no incidence of tibial apophyseal injury at the latest follow-up. Radiographic Koshino index normalized and was maintained all through the follow-up period except in one patient (5%) who was overcorrected. Two patients (4 knees, 20%) showed postoperative knee stiffness due to casting which resolved with physiotherapy within six weeks. One knee (5%) developed a superficial infection which also resolved uneventfully with repeated dressings. CONCLUSION The described infra-patellar plication technique in skeletally immature spastic diplegics appears effective, safe, and reproducible.
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Zhang Z, Zhang H, Song G, Zheng T, Feng H. A pre-operative grade 3 J-sign adversely affects short-term clinical outcome and is more likely to yield MPFL residual graft laxity in recurrent patellar dislocation. Knee Surg Sports Traumatol Arthrosc 2020; 28:2147-2156. [PMID: 31612265 DOI: 10.1007/s00167-019-05736-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 09/26/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE The purposes of this study were to investigate the anatomical risk factors of grade 3 J-sign and analyse the influence of J-sign grades on the short-term clinical outcomes of patients with recurrent patellar dislocation. METHODS From 2016 to 2018, a total of 168 patients with recurrent patellar dislocation (187 knees) underwent medial patellofemoral ligament reconstruction with or without tibial tuberosity medialization. Pre-operative J-sign severity was graded according to a previously described classification (grades 1-3). Potential anatomical risk factors of J-sign were explored. Comparisons were assessed between patients with different grades of J-sign using univariate and binary logistic regression analyses. The Kujala score was assessed and compared with pre-operative values, and stress fluoroscopy was performed to assess medial patellofemoral ligament residual graft laxity. Among the 130 included cases, 104 knees with at least 1-year follow-up were included in the clinical outcome analyses to explore the influence of several anatomical factors and J-sign grade on short-term clinical outcomes. RESULTS A total of 118 patients (130 knees) were included in the present study. The median age at surgery was 21 years (range 13-38), and 111 affected knees belonged to female patients (85%). Univariate and multivariate logistic regressions between the grade 3 group and the grade 1-2 groups showed that increased femoral anteversion, excessive external tibial torsion, and patella alta were three independent risk factors of grade 3 J-sign in patients with recurrent patellar dislocation. A total of 104 knees with at least a 1-year follow-up were included in the clinical outcome analyses. The median Kujala score improved from 54 (range, 38-72) pre-operatively to 86 (range, 70-100) post-operatively. Although no re-dislocation was reported during the follow-up, 6 out of 32 patients in the grade 3 group demonstrated "MPFL residual graft laxity" based on post-operative stress radiography (18.8%), which was significantly higher than in the grade 1-2 groups (0%, p < 0.001). Subgroup analysis showed that patients with grade 3 J-sign had significantly lower post-operative Kujala scores than those with grade 1-2 J-sign (p < 0.001). Moreover, increased femoral anteversion (≥ 30°) was correlated with an inferior post-operative Kujala score (p = 0.023). CONCLUSION The three independent anatomic risk factors of grade 3 J-sign in patients with recurrent patellar dislocation were increased femoral anteversion, excessive external tibial torsion, and patella alta. A pre-operative grade 3 J-sign was correlated with a lower post-operative Kujala score and more "MPFL residual graft laxity" in patients with recurrent patellar dislocation treated with MPFL reconstruction with or without tibial tuberosity medialization at a minimum 1-year follow-up. LEVEL OF EVIDENCE III.
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Vampertzis T, Barmpagianni C, Nitis G, Papastergiou S. A study of the possible effect of abnormal patella height on meniscal tears. J Orthop 2020; 22:170-172. [PMID: 32419759 DOI: 10.1016/j.jor.2020.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/02/2020] [Accepted: 04/26/2020] [Indexed: 12/27/2022] Open
Abstract
Objective Patellar height is key to knee biomechanics. Variations (alta/baja) have been associated with instability/dislocations, ACL ruptures etch. The effect of abnormal patella height and meniscal lesions is not clear yet; this is a first investigation of this relation. Methods 100 patients with meniscal tears were X-Rayed to determine patellar height using the Insall-Salvati ratio and the Caton-Deschamps Index. Results 20% had abnormal patellar height according to the Insall-Salvati ratio and 9% based on the Caton-Deschamps index. Conclusion This indicates that patella height could be a parameter in the occurrence of meniscal injuries worth investigating in larger populations; yet the mechanism remains unclear.
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Dan MJ, McMahon J, Parr WCH, Briggs N, MacDessi S, Caldwell B, Walsh WR. Sagittal patellar flexion angle: a novel clinically validated patellar height measurement reflecting patellofemoral kinematics useful throughout knee flexion. Knee Surg Sports Traumatol Arthrosc 2020; 28:975-983. [PMID: 31289916 DOI: 10.1007/s00167-019-05611-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 07/01/2019] [Indexed: 01/31/2023]
Abstract
PURPOSE Patellar height measurements on lateral radiographs are dependent on knee flexion which makes standardisation of measurements difficult. This study described a plain radiographic measurement of patellar sagittal height which reflects patellofemoral joint kinematics and can be used at all degrees of flexion. METHODS The study had two parts. Part one involved 44 normal subjects to define equations for expected patellar position based on the knee flexion angles for three new patellar height measurements. A mixed model regression with random effect for individual was used to define linear and polynomial equations for expected patellar position relating to three novel measurements of patella height: (1) patellar progression angle (trochlea), (2) patellar progression angle (condyle) and (3) sagittal patellar flexion. Part two was retrospective and involved applying these measurements to a surgical cohort to identify differences between expected and measured patellar position pre- and post-operatively. RESULTS All three measurements provided insight into patellofemoral kinematics. Sagittal patellar flexion was the most useful with the least residual error, was the most reliable, and demonstrated the greatest detection clinically. CONCLUSIONS Clinically applied radiographic measurements have been described for patellar height which reflect the sagittal motion of the patella and can be used regardless of the degree of flexion in which the radiograph was taken. The expected sagittal patellar flexion linear equation should be used to calculate expected patellar height. LEVEL OF EVIDENCE IV.
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Kumar A, Rutherford-Davies J, Thorpe P, Newson A. Combined quadriceps lengthening (using an external ring fixator) and patellar tendon reconstruction (using a tendoachilles allograft) in a case of chronic patellar tendon rupture: A case report. Knee 2020; 27:598-606. [PMID: 32014413 DOI: 10.1016/j.knee.2019.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 12/14/2019] [Accepted: 12/19/2019] [Indexed: 02/02/2023]
Abstract
BACKGROUND Patellar tendon rupture is an infrequent and debilitating condition, which if left untreated, is complicated by quadriceps contracture and patella alta. This results in reduced function of the knee extensor mechanism including extension lag, reduced range of motion (ROM), chronic knee pain, and frequent falls. Early primary repair has good results in most cases and is performed by opposing and suturing the tendon ends. However, when there is a delay between rupture and repair or in case of a re-rupture, primary repair techniques may not work due to retraction of the extensor mechanism. Several treatment modalities have been proposed in such cases, but there is no clear consensus. METHODOLOGY We present the case of a 39-year-old male with chronic rupture of patellar tendon that was reconstructed with a two-stage technique. In the first stage, a ring-fixator was applied to stretch the quadriceps muscle and the second stage consisted of reconstruction of the patellar tendon with a tendoachilles allograft. This procedure was performed in two stages five weeks apart and almost four years after the initial injury. RESULTS Results were excellent at three years' follow-up with the patient achieving full extension, a ROM of 0-110° and 85% quadriceps strength. There was significant improvement in his pain, mobility and quadriceps bulk. CONCLUSION To our knowledge, this treatment has not previously been described in the literature. We present this case as a proven treatment option for treatment of chronic patellar tendon injuries with extensor mechanism shortening.
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Feucht MJ, Lutz PM, Ketzer C, Rupp MC, Cotic M, Imhoff AB, Pogorzelski J. Preoperative patellofemoral anatomy affects failure rate after isolated patellofemoral inlay arthroplasty. Arch Orthop Trauma Surg 2020; 140:2029-2039. [PMID: 33125548 PMCID: PMC7674339 DOI: 10.1007/s00402-020-03651-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/15/2020] [Indexed: 02/06/2023]
Abstract
PURPOSE To analyze whether preoperative patellofemoral anatomy is associated with clinical improvement and failure rate after isolated patellofemoral arthroplasty (PFA) using a modern inlay-type trochlear implant. METHODS Prospectively collected 24 months data of patients treated with isolated inlay PFA (HemiCAP® Wave, Arthrosurface, Franklin, MA, USA) between 2009 and 2016, and available digitalized preoperative imaging (plain radiographs in three planes and MRI) were retrospectively analyzed. All patients were evaluated using the WOMAC score, Lysholm score, and VAS pain. Patients revised to TKA or not achieving the minimal clinically important difference (MCID) for the total WOMAC score or VAS pain were considered failures. Preoperative imaging was analyzed regarding the following aspects: Tibiofemoral OA, patellofemoral OA, trochlear dysplasia (Dejour classification), patellar height (Insall-Salvati index [ISI]; Patellotrochlear index [PTI]), and position of the tibial tuberosity (TT-TG and TT-PCL distance). RESULTS A total of 41 patients (61% female) with a mean age of 48 ± 13 years could be included. Fifteen patients (37%) were considered failures, with 5 patients (12%) revised to TKA and 10 patients (24%) not achieving MCID for WOMAC total or VAS pain. Failures had a significantly higher ISI, and a significantly lower PTI. Furthermore, the proportion of patients with a pathologic ISI (> 1.2), a pathologic PTI (< 0.28), and without trochlear dysplasia were significantly higher in failures. Significantly greater improvements in clinical outcome scores were observed in patients with a higher preoperative grade of patellofemoral OA, ISI ≤ 1.2, PTI ≥ 0.28, TT-PCL distance ≤ 21 mm, and a dysplastic trochlea. CONCLUSION Preoperative patellofemoral anatomy is significantly associated with clinical improvement and failure rate after isolated inlay PFA. Less improvement and a higher failure rate must be expected in patients with patella alta (ISI > 1.2 and PTI < 0.28), absence of trochlear dysplasia, and a lateralized position of the tibial tuberosity (TT-PCL distance > 21 mm). Concomitant procedures such as tibial tuberosity transfer may, therefore, be considered in such patients. LEVEL OF EVIDENCE Level III, retrospective analysis of prospectively collected data.
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Ramanath SK, Shah RH, Patil S, Umesh S. Reconstruction of Neglected Patellar Tendon Rupture using Tendoachilles' Allograft with Transosseous Tunnels: A Case Report. J Orthop Case Rep 2020; 10:27-29. [PMID: 33312974 PMCID: PMC7706442 DOI: 10.13107/jocr.2020.v10.i05.1824] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Introduction: Neglected patellar tendon ruptures are uncommon. They are challenging due to the proximal migration of patella and soft-tissue contractures. They are usually managed with autografts or allografts with or without synthetic augmentation, and fixation is done using metallic implants. Case Report: A 59-year-old farmer presented with an inability to straighten his knee for 6 months after sustaining a cut lacerated wound with a sickle. He was diagnosed with a patellar tendon rupture. Tendoachilles’ allograft reconstruction was done by creating transosseous tunnels in the patella and tibial tuberosity with a figure of 8 con figurations of the final construct. Synthetic augmentation and metallic implants were not used. Excellent clinical and radiological results were achieved at 3 years’ follow-up. Conclusion: Chronic patellar tendon ruptures can be managed using allograft without the need for synthetic augmentation or fixation with implants. This gives excellent clinical and radiological results.
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Yang Y, Zhang Q. Reconstruction of the medial patellofemoral ligament and reinforcement of the medial patellotibial ligament is an effective treatment for patellofemoral instability with patella alta. Knee Surg Sports Traumatol Arthrosc 2019; 27:2599-2607. [PMID: 30421164 DOI: 10.1007/s00167-018-5281-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 10/29/2018] [Indexed: 01/16/2023]
Abstract
PURPOSE To evaluate the clinical outcome of the combined reconstruction of the medial patellofemoral ligament (MPFL) and medial patellotibial ligament (MPTL) for patellar instability with patella alta. METHODS A total of 108 patients underwent a combined reconstruction of the MPFL and MPTL, and 58 patients were included in this study. The clinical results were evaluated and compared using the International Knee Documentation Committee (IKDC) scores, Kujala scores, and visual analogue scale (VAS) scores. The tibial tuberosity-trochlear groove (TT-TG) distance, three indices of patellar height (Insall-Salvati ratio, modified Insall-Salvati ratio, and Caton-Deschamps index), and patellar shift and tilt were defined preoperatively and at the 12- and 24-month follow-up visits. RESULTS At the 12- and 24-month follow-up visits, 86.2% (50/58) and 87.9% (51/58) of the subjective outcomes were excellent, 5/58 (8.6%) and 4/58 (6.9%) were good, 1/58 (1.7%) and 2/58 (3.4%) were fair, and 2/58 (3.4%) and 1/58 (1.7%) were poor. There were significant improvements in the IKDC scores, from 51.9 ± 13.8 preoperatively to 80 ± 19.2 (P < 0.05) at 12 months and 85 ± 13.9 (P < 0.05) at 24 months; Kujala scores, from 55.1 ± 15.2 preoperatively to 82.6 ± 14.9 (P < 0.05) at 12 months and 89.5 ± 10.2 (P < 0.05) at 24 months; and VAS scores, from 58 ± 11 preoperatively to 12 ± 5 (P < 0.05) at 12 months and 11 ± 4 (P < 0.05) at 24 months. The patellar tilt, patellar shift, Insall-Salvati ratio, modified Insall-Salvati ratio, Caton-Deschamps index, and TT-TG distance all decreased significantly compared with the preoperative values, and there were no significant differences between the values at the 12- and 24-month follow-ups. CONCLUSION The results of this study show that a combined reconstruction of the MPFL and MPTL is an effective treatment for patellar instability with patella alta. This article emphasizes the combined effect of MPFL and MPTL instead of MPFL alone and provides an effective option for the treatment of recurrent patellar dislocation with patella alta. LEVEL OF EVIDENCE Case series, Level IV.
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Patella alta and patellar subluxation might lead to early failure with inlay patello-femoral joint arthroplasty. Knee Surg Sports Traumatol Arthrosc 2019; 27:685-691. [PMID: 29785448 DOI: 10.1007/s00167-018-4965-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 04/27/2018] [Indexed: 10/16/2022]
Abstract
PURPOSE With the growing interest in resurfacing procedures, several new implants have been recently introduced for isolated patello-femoral joint arthroplasty (PFA). However, not much data are available for these new techniques or about the right indications for each type of implant. METHODS Out of a retrospective cohort of 20 inlay PFA, 11 PFA with an elevated Insall-Salvati index and an increased patello-femoral congruence angle showed an initial satisfactory result, but presented thereafter with recurrent pain and "clunk" phenomena. They were all revised after a median time of 25 months (range 8-28 months) into an onlay technique PFA and analyzed for their failure mode and revision technique. RESULTS Clinical symptoms such as clunking, as well as abraded areas craniolateral of the inlay implant found intraoperatively, were the main observations of this study. The modified Insall-Salvati index (mISI) was significantly higher in the revised knees compared to the unrevised (median 1.8 versus 1.6; p = 0.041). VAS and KSS significantly improved after revision (median VAS reduction in pain of 4.0 points, median KSS improvement of 20.0 points; p < 0.05). CONCLUSION Patients with high-normal patellar height index or patella alta, as well as a craniolateral type of arthritis with additional lateralization, should be considered contra-indicated for an inlay technique PFA. They could be considered for a PFA system reaching further proximal into the distal femur. An onlay PFA can be an option for early revision of failed inlay implants. The clinical relevance of this study is that patella alta and patellar subluxation are more difficult to adjust for with an inlay PFJ component. LEVEL OF EVIDENCE Level IV.
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Reliability of patellotrochlear index in patellar height assessment on MRI-correction for variation due to change in knee flexion. Skeletal Radiol 2019; 48:387-393. [PMID: 30141067 DOI: 10.1007/s00256-018-3040-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 07/25/2018] [Accepted: 07/30/2018] [Indexed: 02/02/2023]
Abstract
OBJECTIVES To assess the reliability of patellotrochlear Index (PTI) in patellar height assessment on successive MRI scans in asymptomatic patients. MATERIALS AND METHODS Sixty-four patients with two successive MRI scans (128 studies) of the same knee for non-patellofemoral joint symptoms were identified retrospectively. PTI and knee flexion angle were assessed independently by three observers to assess interobserver reliability. The effect of knee flexion on PTI was assessed by comparing the change in values of PTI in each patient correlated with change in knee flexion. RESULTS Sixty-four MRIs of patients (M:F) aged between 18 and 35 years (mean 24.6) years were assessed. The mean PTI for initial scan group was 0.33% (95% CI: 0.29-0.37; SD: 0.15) and consecutive scan group was 0.30% (CI: 0.27-0.33; SD: 0.3). The difference was not significant (p = 0.097 using a paired t test) with high inter-observer correlation (0.9) in both sets. Spearman's rho for knee flexion angle and PTI was found to be positive and statistically significant (0.41; p = 0.001). A linear regression model was derived using a scatter chart of change in PTI with change in knee flexion for each patient. The gradient of the linear regression line was used to estimate a cPTI (corrected PTI) value (corrected to 0 degrees of knee flexion), defined as cPTI = PTI - 1.3a (a = knee flexion angle). CONCLUSIONS This study demonstrates high inter-observer correlation of PTI on MRI and high test-retest reliability indicating unconscious quadriceps contraction does not change the index sufficiently. Knee flexion significantly alters PTI, increased patellotrochlear engagement with flexion increases the index. We propose use of the formula cPTI = PTI -1.3a to correct the index to 0 degree knee flexion in clinical practice.
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Association of patella alta with worsening of patellofemoral osteoarthritis-related structural damage: data from the Osteoarthritis Initiative. Osteoarthritis Cartilage 2019; 27:278-285. [PMID: 30445221 DOI: 10.1016/j.joca.2018.10.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 10/01/2018] [Accepted: 10/04/2018] [Indexed: 02/02/2023]
Abstract
OBJECTIVES To determine the association between Insall-Salvati ratio (ISR), a measure of patella alta, and worsening of Magnetic Resonance Imaging (MRI)-based osteoarthritis (OA)-related patellofemoral joint structural damages over 24-month in participants of the Osteoarthritis Initiative (OAI). DESIGN Using weighted random sampling method, we selected a sample of 500 knees (from 1,677 knees with available baseline and 24-months MRI OA Knee Score (MOAKS) measurements), which is OAI-representative regarding knee OA-related factors (i.e., baseline age, sex, body mass index (BMI), and radiographic Kellgren-Lawrence grading). The ISR was measured in all enrolled knees using baseline sagittal 3T-MRI plane by three radiologists. Baseline and 24-month MOAKS variables for patellofemoral bone marrow lesions (BMLs), cartilage damages, and osteophytes were extracted, and the associations between ISR and 24-month worsening of these 3T-MRI features were evaluated using multivariable regression models. After computing receiver operating characteristic curves, the optimal cutoff point of ISR for indicating worsening of patellofemoral OA was determined. P-values were adjusted for multiple comparisons and false discovery rate (FDR) adjusted P-values were reported. RESULTS In this longitudinal analysis, 24-month worsening of BML (odds ratio [OR] (95% confidence interval [95% CI]):11.18 (3.35-39.6), adjusted-p-value:<0.001) and cartilage scores (OR:7.39 (1.62-34.71), adjusted-p-value:0.042) in lateral patella was associated with higher baseline ISR. However, higher ISR was not statistically associated with medial patellar or medial and lateral trochlear BML or cartilage scores worsening. We determined the optimal cutoff point of ISR≥1.14 (95% CI: 1.083-1.284) for predicting lateral patellofemoral OA-related structural damages worsening over 24-months (sensitivity:73.73%; specificity: 66.67%). CONCLUSIONS Given the uncertainly surrounding the results, our overall findings suggest that ISR could be considered as a predictor of lateral patellofemoral OA-related structural damages worsening with the optimal cutoff point of ≥1.14 using knee sagittal MRI measurements.
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Bartsch A, Lubberts B, Mumme M, Egloff C, Pagenstert G. Does patella alta lead to worse clinical outcome in patients who undergo isolated medial patellofemoral ligament reconstruction? A systematic review. Arch Orthop Trauma Surg 2018; 138:1563-1573. [PMID: 29948223 DOI: 10.1007/s00402-018-2971-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Indexed: 02/09/2023]
Abstract
INTRODUCTION The aim of this systematic review is to determine the effect of patella height on clinical outcomes after isolated MPFL reconstruction for patella instability. Our primary hypothesis is that patients with patella alta report similar outcomes after isolated MPFL reconstruction compared to patients with normal patella height. METHODS A review of the literature was performed according to the PRISMA guidelines. PubMed, EMBASE, and the Cochrane Library were searched from inception to January 10th 2018. Studies were identified using synonyms for "medial patellofemoral ligament", "reconstruction" and "patella alta". RESULTS The search resulted in 467 reports on PubMed, 175 on EMBASE and 3 on the Cochrane Library. We included and analyzed in detail six studies describing outcomes after isolated medial patellofemoral ligament reconstruction with regard to patellar height. We found that both patients with patella alta and normal patella height reported satisfactory outcomes after isolated medial patellofemoral ligament reconstruction. However, because of applied exclusion criteria in the included studies the total number of patients with severe patella alta was small (13/74 patients with patella alta, 18%). CONCLUSIONS Based on the current literature we suggest that additional tibial tubercle distalisation is not mandatory in patients with mild patella alta (Caton-Deschamps Index 1.2-1.4). To assess the best indications for different surgical procedures for patients with patella instability future research is needed to develop a clear and uniform definition of relevant patella alta. LEVEL OF EVIDENCE III.
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Roessler PP, Wimmer MD, Jacobs C, Bornemann R, Stein T, Lahner M. Medial patellofemoral ligament reconstruction fails to correct mild patella alta in cases of patellofemoral instability-a case-control study. INTERNATIONAL ORTHOPAEDICS 2018; 43:2071-2075. [PMID: 30225588 DOI: 10.1007/s00264-018-4162-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/12/2018] [Indexed: 01/25/2023]
Abstract
PURPOSE Medial patellofemoral ligament reconstruction (MPFL-R) is the gold standard in patella soft tissue surgery for patellofemoral instability. Although claimed, recent reports indicate that MPFL-R may fail to distalize the patella in mild cases of patella alta. The present study is a retrospective case-control study to compare radiographic patella height between MPFL-R and historical Insall's proximal realignment (IPR) pre- and post-operatively with respect to distalization and assess redislocation rates at a mid-term follow-up. METHODS Sixty-four patients were age/sex matched (1:1), yielding 32 patients for group 1 MPFL-R (cases) and 32 patients for group 2 IPR (controls). Insall-Salvati, Blackburne-Peel and Caton-Deschamps indices were analyzed for differences pre- and post-operatively. An additional inter-rater reliability analysis was performed by means of intra-class correlation (ICC). Redislocation rates were considered as treatment failures in this study. RESULTS ICC was excellent for all three patella indices. MPFL-R failed to show significant differences if compared to IPR with respect to distalization in mild stages of patella alta. Moreover, redislocation rates significantly favored MPFL-R (3.1%) over IPR (12.5%; p < 0.0001). CONCLUSIONS MPFL-R has become a popular option to restore native patellofemoral biomechanics after ligament rupture. However, the procedure's potential to correct concomitant patella alta should not be overestimated and indications considered carefully.
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Bittmann MF, Lenhart RL, Schwartz MH, Novacheck TF, Hetzel S, Thelen DG. How does patellar tendon advancement alter the knee extensor mechanism in children treated for crouch gait? Gait Posture 2018; 64:248-254. [PMID: 29958159 PMCID: PMC6181142 DOI: 10.1016/j.gaitpost.2018.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND The patellar tendon advancement (PTA) procedure, often coupled with a distal femoral extension osteotomy (DFEO), is increasingly used to treat persistent crouch gait. In this study, we investigated relationships between patella position, knee flexion, and the patellar tendon moment arm in children treated with the DFEO and PTA procedures. METHODS We retrospectively analyzed pre- and post-operative radiographs and gait metrics from 63 knees that underwent DFEO and PTA procedures at Gillette Children's Specialty Healthcare. A computational musculoskeletal model of the knee was used to simulate the PTA procedure and predict the effects on the patellar tendon moment arm. RESULTS Approximately 80% of the knees exhibited patella alta prior to surgery. Post-operatively, 86% of the knees exhibited patella baja. The surgically altered patella position produced a 13% increase in the patellar tendon moment arm in extended knee postures, which agreed well with model predictions. However, the computational model also suggests that baja may compromise patellar tendon moment arms in flexed knee postures. Crouch gait was significantly reduced postoperatively, with a 27 ± 18° reduction in average knee flexion in stance. There was considerable inter-subject variability in outcomes with nine knees not exhibiting a meaningful enhancement of knee extension (<15° change). The subjects who improved were significantly younger and exhibited greater enhancement of the patellar tendon moment arm after surgery. CONCLUSIONS This study shows that the PTA procedure enhances the lever arm of the knee extensor mechanism, and this factor may be important in resolving crouch gait.
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Abstract
PURPOSE OF REVIEW Historically, the standard of care for patients with an acute patella dislocation has been non-operative with the exception being those with a loose body or osteochondral fracture requiring fixation or removal. RECENT FINDINGS Recent literature has brought into question this standard of care approach and defined a higher risk subset of first-time dislocators who may benefit from early operative treatment. In addition, these studies suggest that operative treatment not only reduces the risk of recurrence but may improve outcomes overall and specifically in the pediatric population. Though the "high risk" population of first-time dislocators has been more clearly defined, how we treat them remains controversial. We continue to need more evidence-based guidelines to help us manage who we should be fixing and how we should be fixing them. We currently have several multi-center studies in progress, including one specifically looking at the question of medial patellofemoral ligament reconstruction in first-time pediatric and adolescent dislocators.
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Otsuki S, Okamoto Y, Murakami T, Nakagawa K, Okuno N, Wakama H, Neo M. Patellofemoral reconstruction for patellar instability with patella alta in middle-aged patients: Clinical outcomes. Orthop Traumatol Surg Res 2018; 104:217-221. [PMID: 29410197 DOI: 10.1016/j.otsr.2018.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 11/23/2017] [Accepted: 01/03/2018] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Although several surgical treatments for patellar instability with patella alta have been reported, the clinical outcomes and optimal surgical procedures for patellar instability with patella alta in middle-aged patients are still controversial. We hypothesized that optimal surgical procedures for patellar instability with patella alta in middle-aged patients may induce good clinical outcomes with better patellofemoral geometry. MATERIALS AND METHODS Twelve middle-aged patients with a mean age of 44 years (range: 40-55 years), who presented with patellar instability and patella alta, were treated with a combination of several surgeries, such as medial patellofemoral ligament (MPFL) reconstruction, trochleoplasty, lateral release, and three-dimensional transfer of the tibial tuberosity, based on a surgical algorithm. Patellar position and clinical outcomes were evaluated postoperatively. The mean follow-up time was 41.5 months (range: 24-72 months). RESULTS Patellar position altered from 1.31 (1.21-1.53) preoperatively to 0.88 (0.69-1.06) postoperatively on the Caton-Deschamps Index (p<0.01). The tibial tuberosity-trochlear groove (TT-TG) distance altered from 21.8mm (20.1-25.8mm) to 10.3mm (5.1-14.7mm), and patellar tilt ranged from 28.1° (21-40°) to 14.6° (5-28°), respectively (p<0.01). Clinical outcomes on the Lysholm and Kujala scales improved from 43.1 and 38.4 to 86.7 and 78.3, respectively, at final follow-up (p<0.01). Surgical treatment that included trochleoplasty resulted in better outcomes than other surgical combinations without trochleoplasty (p<0.05). Sulcus angle and postoperative patellar tilt improved more in those who underwent trochleoplasty than in those who did not (p<0.05). DISCUSSION Surgical treatment for patellar instability with patella alta in middle-aged patients resulted in improved clinical outcomes. In particular, a combination surgery including trochleoplasty resulted in the greatest improvement in case of severe trochlear dysplasia. LEVEL OF EVIDENCE IV. Retrospective case series study.
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Pesenti S, Ollivier M, Escudier JC, Cermolacce M, Baud A, Launay F, Jouve JL, Choufani E. Medial patellofemoral ligament reconstruction in children: do osseous abnormalities matter? INTERNATIONAL ORTHOPAEDICS 2018; 42:1357-1362. [PMID: 29299655 DOI: 10.1007/s00264-017-3750-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 12/20/2017] [Indexed: 11/27/2022]
Abstract
PURPOSE Management of post-traumatic patellar instability in children with osseous abnormalities is challenging because of the presence of an open physis. The aim of our study was to compare the rate of recurrence after isolated reconstruction of the medial patellofemoral ligament (MPFL) in children with or without osseous abnormalities. METHODS The medical records of 25 children (27 knees) with recurrent patellar dislocation were reviewed. Each child underwent an isolated reconstruction of the MPFL using a hamstring graft. At the last follow-up, a clinical and radiographic evaluation was performed, including assessment of functional outcomes based on the Kujala score. Patients were compared in terms of the occurrence of a pre-existing osseous abnormality. RESULTS The mean age at the time of the surgery was 13.8 years. Eleven patients had trochlear dysplasia (40%), three had a patella alta (11%) and seven had an increased TT-TG (26%). The recurrence rate was 3.7% (one patient), after a mean follow-up of 41.1 months. Recurrence was not more frequent in patients with preoperative anatomical predisposing factors. The mean Kujala score was 95. The mean time to return to practicing sports was 7.1 months. CONCLUSIONS Isolated MPFL reconstruction is an effective option for the management of post-traumatic patellofemoral instability in skeletally immature patients. The results of this technique seem to be independent on either proximal or distal misalignments such as trochlear dysplasia, patella alta, or increased TT-TG.
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Arendt EA, England K, Agel J, Tompkins MA. An analysis of knee anatomic imaging factors associated with primary lateral patellar dislocations. Knee Surg Sports Traumatol Arthrosc 2017; 25:3099-3107. [PMID: 27145773 DOI: 10.1007/s00167-016-4117-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 03/29/2016] [Indexed: 01/27/2023]
Abstract
PURPOSE Various knee anatomic imaging factors have been historically associated with lateral patellar dislocation. The characterization of these anatomic factors in a primary lateral patellar dislocation population has not been well described. Our purpose was to characterize the spectrum of anatomic factors from slice imaging measurements specific to a population of primary lateral patellar dislocation. A secondary purpose was to stratify these data by sex/skeletal maturity to better detail potential dimorphic characteristics. METHODS Patients with a history of primary lateral patellar dislocation between 2008 and 2012 were prospectively identified. Ten MRI measurements were analysed with results stratified by sex/skeletal maturity. A '4-factor' analysis was performed to detail the number of 'excessive' anatomic factors within a single individual. RESULTS This study involved 157 knees (79 M/78 F), and 107 patients were skeletally mature. The measurements demonstrate more anatomic risk factors in this population than historical controls. Patella height and trochlear measurements are the most common 'dysplastic' anatomic factors in this population. There were differences based on sex for some patellar height measurements and for TT-TG; there were no differences based on skeletal maturity. CONCLUSION Primary lateral patellar dislocation patients have MRI measurements of knee anatomic factors that are generally more dysplastic than the normal population; however, there is a broad spectrum of anatomic features with no pattern predominating. Characterizing knee anatomic imaging factors in the patient with a primary lateral patellar dislocation is a necessary first step in characterizing the (potential) differences between the primary and recurrent patellar dislocation patient. LEVEL OF EVIDENCE IV.
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Abstract
BACKGROUND Patella lowering aims to improve quadriceps function as a means of correcting crouch gait in patients with cerebral palsy. Few studies have assessed the effects of patella lowering as a component of multilevel surgery. HYPOTHESIS Including patella lowering into the components of multilevel surgery is beneficial in patients with crouch gait and patella alta. MATERIAL AND METHODS In 12 lower limbs with patella alta (Caton-Deschamps index>1.4) in 41 children with cerebral palsy, patella lowering was performed, without distal femoral extension osteotomy or hamstring release. Among limbs with similar surgical procedures (e.g., hamstring lengthening, rectus femoris transfer) except for patella lowering, controls were selected retrospectively by matching on a propensity score for patella lowering. The propensity score was computed based on preoperative knee flexion contracture, knee extension lag, and minimum knee flexion at mid-stance. Clinical and 3D kinematic data were compared between the two groups. RESULTS The improvement in minimum knee flexion at mid-stance was significantly greater in the group with patellar lowering (-24°±12°vs. -12°±7°). The Gait Deviation Index improved similarly in the two groups. Knee flexion contracture improved only in the group with patellar lowering. Extension lag did not improve in either group. Peak knee flexion during the swing phase remained unchanged in both groups. DISCUSSION Patellar lowering is effective in diminishing minimum knee flexion at mid-stance in patients with patella alta and crouch gait due to cerebral palsy. Patellar lowering has not adverse effects on gait. These findings cannot be assumed to apply to patients with normal patellar height. LEVEL OF EVIDENCE IV (retrospective study).
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Influence of age on clinical outcomes of three-dimensional transfer of the tibial tuberosity for patellar instability with patella alta. Knee Surg Sports Traumatol Arthrosc 2017; 25:2392-2396. [PMID: 26837641 DOI: 10.1007/s00167-015-3825-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 09/25/2015] [Indexed: 10/22/2022]
Abstract
PURPOSE To evaluate the clinical outcomes of three-dimensional (3D) transfer of the tibial tuberosity for patellar instability with patella alta, with a focus on the influence of age at initial surgery. METHODS Three-dimensional surgery was performed on 28 knees with a mean follow-up of 46 months. Patients were separated into three groups based on the age at initial surgery: group A, 10 knees and an average age of 16.3 ± 1.8 (14-19) years; group B, 10 knees and an average age of 22.1 ± 2.5 (20-28) years; and group C, eight knees and an average age of 44.0 ± 2.2 (40-46) years. Patellofemoral geometry improvement focused on patella alta by determining the Insall-Salvati ratio and Caton-Deschamps index, rotational malalignment by measuring the tibial tubercle-trochlear groove (TT-TG) distance, and lateral patellar subluxation by measuring the patellar tilt. Clinical outcomes were evaluated by the Lysholm and Kujala scores, which were compared before and after surgery. Cartilage degeneration was evaluated by the International Cartilage Repair Society grading system at initial arthroscopy. RESULTS The patellar height, TT-TG, and patellar tilt significantly improved in all groups postoperatively (p < 0.05). The Lysholm and Kujala scores also significantly improved postoperatively; however, both scores were lower in group C than in the other groups (p < 0.05). Particularly, pain scores were more severe in group C than in the other groups, and the severity of cartilage degeneration correlated with the pain scores (p < 0.05). Cartilage damage differed significantly between the groups at initial arthroscopy; particularly, group C included grades III and IV cartilage degeneration (p < 0.05). CONCLUSIONS Age at initial surgery may be the predicting factor for poor clinical outcomes of 3D transfer surgery. The clinical outcome may depend on the age at surgery, which correlated with cartilage damage; thus, surgeons should be given this information when patients are considered undergoing patella surgery. LEVEL OF EVIDENCE Therapeutic case series, Level IV.
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Prudhon JL, Caton JH, Aslanian T, Verdier R. How is patella height modified after total knee arthroplasty? INTERNATIONAL ORTHOPAEDICS 2017; 42:311-316. [PMID: 28688007 DOI: 10.1007/s00264-017-3539-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 06/14/2017] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Since the first measurement method of patella height in 1929 (Janssen), more than 16 methods have been described. Most of these measures are not suitable to measure patella height after total knee arthroplasty (TKA). One of us (JC) modified the original Caton Deschamps (oCD), index with a new relative index called modified Caton Deschamps (mCD) index, by using new landmarks. The purpose of this study was to determine how patella height is modified after TKA. MATERIAL AND METHOD Sixty primary TKAs were consecutively prospectively enrolled. One type of implant was used (cementless postero-stabilized TKA, rotating plateau, cemented patella resurfacing). Patient's characteristics, functional and radiological outcomes were recorded pre-operatively and at one year follow-up. Pre-operative and post-operative outcomes were compared by paired t-test. Post-operative outcomes were compared between groups by one-way analysis of variance. RESULTS Average difference between pre and post-operative mCD was 0.19 in this series. In 81.7% of cases, patella was lowered. Patients were classified in three groups according to patella height lowering. Between these three groups, no significant statistical differences (IKS score knee and function, range of motion) could be identified. DISCUSSION In TKA, patella assessment in sagittal plane is as important as frontal or horizontal planes. True patella infera (TPI) is mostly due to patella tendon shortening measured by oCD. Pseudo patella infera (PPI) measured by mCD is mostly due to joint line elevation (over femoral cut with an over thickness of the tibial component). In this study a moderate patella lowering (minor than 15%) does not have a significant impact on the functional results (IKS, ROM) nevertheless in 80% patella is lowered. The next step will be to analyze precisely what factors are influencing this lowering and what prevention could be suggested in primary and revision TKA.
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Łojszczyk-Szczepaniak A, Silmanowicz P, Komsta R, Osiński Z. Determination of reference values and frequency of occurrence of patella alta in German shepherd dogs: a retrospective study. Acta Vet Scand 2017; 59:36. [PMID: 28569198 PMCID: PMC5452377 DOI: 10.1186/s13028-017-0304-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 05/22/2017] [Indexed: 12/21/2022] Open
Abstract
Background Patella alta and patella baja are important conditions underlying a predisposition to many joint diseases, including patellar luxation and patellar chondromalacia of the articular cartilage. The frequencies of patella alta and patella baja have not yet been determined. The objectives of this study were to determine the frequency of patella alta and to determine reference values to the position of the vertical patella according to two modified techniques of the Insall–Salvati method in a group of 65 German shepherd dogs (115 stifle joints). Results The upper limits of reference values for the normal vertical position of the patella were 1.79 and 2.13, depending on the method of measurement. A high prevalence of patella alta was observed in the group of German shepherd dogs. A correlation was demonstrated between the classification of dogs’ joints in the patella alta group and the multiplied risk of canine hip dysplasia (CHD) through the estimation of odds ratios. Conclusions Dogs with patella alta were healthy dogs that did not exhibit orthopaedic problems in the stifle joints. The results revealed that the risk of CHD is twice as high in dogs with higher patellar ligament length to patella length ratio.
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