Changes In Patellar Tendon Length Research Articles

The Basas Spanish Squat: Superimposition of Electrical Stimulation to Optimize Patellar Tendon Strain: A Case Series.

The Basas Spanish Squat with electrical stimulation (E-stim) has shown promising results as a potential key exercise in treatment of athletes with patellar tendinopathy. Gold standard exercise therapy for tendon injuries consists of tendon loading exercises, or exercises that appropriately applies high levels of mechanical strain to the tendon. The theoretical pathway in which the Basas Spanish Squat with E-stim improves tendinopathy has been speculated to be the additional strain applied through the patellar tendon during superimposition of E-stim. This theory, however, has yet to be confirmed. The purpose of this case series was to compare patellar tendon strain, during the Basas Spanish Squat with, and without E-stim, and open kinetic chain knee extension. Four healthy participants performed the three exercises while a physical therapist collected simultaneous unilateral ultrasound images from the patellar tendon. Strain was calculated as the change in patellar tendon length during contraction divided by the resting length. Amongst all participants, patellar tendon strain was smallest during the Basas Spanish Squat without E-stim, followed by the open kinetic chain knee extension at 60% maximum voluntary isometric contraction. The Basas Spanish Squat with E-stim yielded approximately double or more strain compared to the without E-stim condition and demonstrated higher level of strain compared to open kinetic chain knee extension in all participants. The findings reflect a clear trend of increased strain through the patellar tendon when E-stim was superimposed. The results support the theory that the Basas Spanish Squat with E-stim increases patellar tendon strain and could explain the reported clinical benefits in individuals with patellar tendinopathy. 4, Case series.

Magnetic resonance imaging analysis on the effect of marathon on the dynamic changes of morphological characteristics of patellar tendon in amateur marathon runners after half marathon

Objective: To explore the dynamic changes of morphological characteristics of patellar tendon (PT) in amateur athletes after a half-marathon using magnetic resonance imaging. Methods: A total of 19 male amateur marathon runners with 38 knee joints,aged from 26 to 53(41.5±7.9) years, running for 3 to 18 years, with a weekly running volume of 30-90 km and a monthly running volume of 100-300 km were enrolled and underwent 1.5T MRI scan before the half-marathon, within 3 hours after running and 3 days after running. Ten healthy male volunteers with 20 knee joints, who had never participated in marathon and exercised (including but not limited to running) per week for less than 150 minutes were recruited as the control group, aged from 26 to 54 (39.4±9.1) years. Firstly, the PT signal was qualitatively assessed on fat-suppressed proton density-weighted imaging (fs-PDWI) sequence to observe the presence of patellar tendinitis. Then, the length, proximal, middle and distal cross-sectional area (CSA), and volume of PT were measured using the post-processing tool ITK-SNAP, and the data were standardized. The independent sample t-test was used for comparing. One-way repeated measures analysis of variance was used to analyze the morphological changes of PT before and after half-marathon running. Results: The incidence of asymptomatic patellar tendinitis in amateur marathon runners was 26.3% (5/19). No significant MR signal changes of PT were observed in all runners after running. The proximal CSA in runners group was larger than that in controls [(4.20±0.62) mm2/kg3/4 vs (3.63±0.57) mm2/kg3/4, P<0.05], and there was no significant difference in length, medium and distal CSA and volume(all P>0.05). The length, proximal and distal CSA and volume of PT in runners group increased at 3 h after running [(47.35±3.22) mm vs (46.83±3.35) mm; (102.52±13.03) mm2 vs (98.98±13.14) mm2; (108.67±15.72) mm2 vs (100.27±14.37) mm2; (4 020.36±514.38) mm3 vs (3 826.57±499.23) mm3, all P<0.05]. There was no significant difference between before running and 3 days after running(all P>0.05). The middle CSA were not significantly different among different periods(all P>0.05). Conclusion: Marathon has effect on the normal PT morphology in male amateur marathon runners, showing an increase in proximal CSA. A half-marathon will cause reversible changes in PT length, regional CSA and volume.

MODELING OF PATELLA HEIGHT WITH DISTAL FEMUR AND PROXIMAL TIBIA REFERENCE POINTS WITH ARTIFICIAL NEURAL NETWORK

The patellofemoral joint is one of the parts of the knee extension mechanism that plays a role in the stability of the knee by enlarging the force arm of the quadriceps muscle and changing the direction of the muscle strength. For the entire knee joint to perform its task painlessly and functionally, the positions and strength of the muscles, the strength of the ligaments, and their reaction to movement must be compatible. The Insall–Salvati (Ins-Sal) index is useful for showing changes in patellar height produced by repositioning the tibial plateau, in other words, showing changes in patellar tendon length. Patella height is an important value to be taken into account in knee prosthesis surgery, tibial osteotomy, and anterior cruciate ligament reconstruction. The morphometric relationship between the reference measurements of the distal femur and proximal tibia and the position of the patella will be useful in determining the natural anatomy. In this study, we aimed to determine the relationship between patella height and distal femur and proximal tibia reference areas by using the artificial neural network method as an alternative approach method. In order to assess the performance of the estimation of the Ins-Sal index, the four ANN model with six input combinations which included age, gender and the reference measurements for the right and left sides have been constructed and tested. The MSE and [Formula: see text] values are calculated for every four models for the training and test phase. The results show that the proposed approach for modeling of relation between reference measurements and the Ins-Sal index is a powerful approach.

Patellar Tendon Imbrication Is a Safe and Efficacious Technique to Shorten the Patellar Tendon in Patients With Patella Alta.

Background:Patella alta has been noted to be a risk factor for recurrent patellar instability.Purpose:We conducted a radiographic study to determine whether a patellar tendon imbrication technique normalizes patellar height as well as whether the shortened length is maintained at a minimum 2-year follow-up.Study Design:Case series; Level of evidence, 4.Methods:A total of 54 consecutive patients were identified after a retrospective chart review was performed on patients who underwent patellar tendon imbrication between 2008 and 2013. Preoperative, 3 weeks postoperative, and minimum 2 years postoperative lateral radiographs were analyzed using Insall-Salvati (IS), Blackburne-Peel (BP), and Caton-Deschamps (CD) indices to determine the amount of shortening that was achieved after the procedure and to what degree that shortening was maintained at a minimum 2-year follow-up.Results:A total of 27 patients (32 knees) completed a minimum 2-year follow-up. The mean patellar tendon length preoperatively was 6.1 cm (range, 5-8 cm). At 3 weeks and 2 years, the mean tendon lengths were 5.1 and 5.2 cm, respectively. Thus, the mean ± SD change in patellar tendon length from preoperative to 3 weeks postoperative was 0.97 ± 0.67 cm. IS, BP, and CD ratios had minimal change (loss of correction) from 3-week to 2-year follow-up; the delta values were 0.04, –0.03, and 0.09, respectively. There were no complications directly related to the technique.Conclusion:Patellar tendon imbrication is a safe and effective procedure to correct patella alta in the setting of lateral patellar instability. On average, the technique allowed 1 cm of patellar tendon shortening and maintained the correction at a minimum 2-year follow-up. In the skeletally immature patient, this technique allows correction of patella alta by avoidance of a tibial tuberosity osteotomy.

Radiographic evaluation of patellar tendon length following corrective surgical procedures for medial patellar luxation in dogs.

To quantify changes in the patellar tendon length following surgical correction of medial patellar luxation in dogs and evaluate potential risk factors associated with patellar tendon elongation. Retrospective case series (n = 50). Dogs that underwent surgery for medial patellar luxation correction and had 2-3 months follow up were included. Digital radiographs were utilized to quantify the patellar tendon length to patellar length ratio at various follow-up points. Odds ratio comparisons between potential risk factors associated with changes in patellar tendon length were performed. Post-operative patellar tendon lengthening of ≥ 5% was observed in 20% of stifles and post-operative patellar tendon shortening of ≥ 5% was observed in 22% of stifles at the 2-3 month follow up period. The risk factors including age, body weight, trochleoplasty and grade of medial patellar luxation were not significantly associated with risk of patellar tendon elongation. Patellar tendon lengthening was not associated with recurrence of luxation. Patellar tendon lengthening and shortening can be observed in dogs following common medial patellar luxation corrective procedures in the short term follow up period. Patellar tendon lengthening does not appear to be associated with age, weight, trochleoplasty, grade of luxation, or risk of luxation recurrence.

Patellar Impingement on Tibial Polyethylene after Primary Total Knee Arthroplasty without Patellar Resurfacing.

Patellar impingement on tibial polyethylene (PIP) is one potential complication of total knee arthroplasty (TKA). When PIP occurs, it is often related to inaccurate restoration of the joint line or due to soft-tissue contracture. We investigated the prevalence and etiology of PIP in Asian patients with deeply flexed knees following posterior stabilized (PS)-TKA. We retrospectively reviewed 54 patients (65 knees) with PIP after primary PS-TKAs without patellar resurfacing performed between 2008 and 2011. These patients were compared with a group of 124 patients (130 knees) without PIP matched for age, sex, and body mass index (BMI). The minimum follow-up was 5 years (range, 5-8.1 years). Patients were evaluated by blinded, independent observers using the Oxford knee score, the Waters score, and radiographic parameters. Impingement between the patella and the tibial polyethylene had a mean onset of 13.5 months after PS-TKA. The development of PIP was significantly associated with change in patellar tendon length (odds ratio [OR] = 11.4, 95% confidence interval [CI]: 11.2-11.6%), shorter postoperative patellar tendon length (OR = 2.1, 95% CI: 1.8-2.5%), change in the Insall-Salvati ratio (OR = 0.9, 95% CI: 0.8-1.0%), and joint line elevation (OR = 5.3, 95% CI: 4.8-5.8%) on multiple logistic regression analysis. Our findings reinforce the importance of accurate joint line restoration and the avoidance of iatrogenic injury to the patellar tendon, which can lead to shortening of the patellar tendon. This is a retrospective comparative study and its level of evidence is III.

Influence of loading rate and limb position on patellar tendon mechanical properties in vivo

BackgroundThe aims of this study were to clarify the changes of patellar tendon length during isometric knee joint extension and the double leg squat position using ultrasonography. MethodsThe left legs of 17 healthy adults were investigated. Isometric knee extension motion was performed at three positions of knee flexion 30° (knee 30°), knee flexion 60° (knee 60°), knee flexion 90° (knee 90°), and at each limb position, 0% (0% peak torque (PT)), 40% (40% PT), 50% (50% PT), and 60% (60% PT) of the maximum knee joint extension torque were executed at random. Both double leg squat motions were randomly performed in three positions: hip flexion 30°, knee flexion 30°, ankle dorsiflexion 10° (squat 30°); hip joint flexion 60°, knee joint flexion 60°, ankle dorsiflexion 20° (squat 60°); and hip joint flexion 90°, knee joint flexion 90°, ankle dorsiflexion 30° (squat 90°). Ultrasonography was used to measure patellar tendon length. FindingsThere were no significant changes in patellar tendon length and strain between knee flexion angles of 30°, 60°, and 90° in isometric knee joint extension and the double leg squat limb position. InterpretationThe loading rate and limb position do not appear to affect the length and strain of the patellar tendon.

Changes in patellar tendon length during passive knee flexion in the menstrual cycle

Changes in patellar tendon length during passive knee flexion in the menstrual cycle

Fat pad excision in total knee arthroplasty does not affect functional outcome or anterior knee pain at 1 year follow-up

BackgroundIn total knee arthroplasty (TKA), excision of infra patellar fat pad (IPFP) is usually done to enhance exposure. But effects of this are not clearly understood. A few studies indicate that it may lead to increased incidence of anterior knee pain (AKP). This study was undertaken to determine the effect of excision of IPFP on incidence of AKP (as indicated by Hospital for Special Surgery (HSS) patella score), Knee society score (KSS) and functional score, change in Patellar Tendon length (as measured by Insall-Salvati ratio (ISR)) and, Range of motion (ROM). Methods135 patients (151 knees) operated by two senior arthroplasty surgeons in the period of January 2014 to December 2015 were followed-up for minimum of 1year. Group 1 consisted of 106 knees in which complete excision of fat pad was done and group 2 consisted of 45 knees in which fat pad was retained. ResultsThere was no significant difference in HSS patella score of two groups during the follow-up of 1 year. KSS and functional score was significantly better for IPFP retention group at 6 week follow-up, but in later follow-ups till 1 year, the difference was not significant. The mean change in patellar tendon length for patients with the fat pad removed (ISR=−0.022) and those with it retained (−0.011) was significantly different (p=0.026). Average range of flexion in both the groups at 1 year follow-up was beyond 110 degrees. There was a significant difference in range of flexion at 1 year of follow-up (117.07 degrees in group 1 versus 118.44 degrees in group 2, p=0.04). There were no fracture or avascular necrosis of patella in either group. ConclusionAKP and functional outcome is not significantly affected by excision of IPFP. Fat pad can be sacrificed if exposure is compromised.

Influence of prosthetic joint line position on outcome after total knee replacement

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; The current study had been designed so as to assess whether joint line elevation and change in patellar tendon length influences knee flexion after primary cruciate retaining TKR.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; This prospective study involved patients with advanced degenerative joint disease involving one or both knees who presented to the outpatient department of a tertiary care hospital. Exclusion criteria were any prior knee surgery. Surgery was performed under tourniquet with standard medial para-patellar arthrotomy to expose all our knees. In the study radiological assessment was done by true lateral X-ray view of knee in 30 degree of flexion. We choose Caton-Deschamps indices (CI) for diagnosis of post TKR patella infera and joint line elevation. CI&amp;lt;0.6 was defined as patella infera (normal range of CI 0.60-1.45). After all data collection comparison was done between joint line elevation versus without joint line elevation patients (with/without patellar tendon shortening) range of movement.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Total of 100 patients (72 females and 28 males) with 176 knees (bilateral=76, unilateral=24) who fulfilled the above said criteria involved in study. The mean age of the patients at the time of surgery was 64.4 years with range of 54 years to 80 years. The average follow up of 24 months, with minimum follow up of 18 months. Average range of motion (ROM) in NO Joint line elevation/patella tendon shortening patient measured 107.2&lt;sup&gt;°&lt;/sup&gt;, and joint line elevation with patellar tendon shortening (prior patella infera) and joint line elevation without patella tendon shortening(prior patella infera) patient average ROM was measured 86.7 and 87.8 degree respectively.&lt;/p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; In our study patellar tendon shortening and joint line elevation reduces ROM knee. Mechanical factors also explain the association between joint line elevation and patellar tendon length with range of motion. Reduction in length of extensor apparatus reduces the range of flexion.

Influence of sagittal plane malpositioning of the patella on anterior knee pain after tibia intramedullary nailing.

Anterior knee pain (AKP) is one of the most common complications after tibia intramedullary surgery. We evaluated changes in patellar tendon length after tibia intramedullary nailing surgery using a transtendinous approach and assessed the importance of nail position in relation to the anterior tibial cortex and joint line. Two surgeons blinded to patients' pain status measured both the knee Insall-Salvati and Caton-Deschamps indexes on 30° flexion lateral knee X-rays of 33 patients. Superior nail prominence (the distance from the proximal tip of the nail to the tibial plateau) and anterior nail prominence (the distance from the anterior tip of the nail to the anterior tibial cortex) were measured on the CT. Clinical assessment showed that 10 patients (30%) had AKP at the last follow-up. HSS and Lysholm scores and the incidence of AKP were similar between patients whose IM nails were removed and those who still had them. HSS score, Insall-Salvati, and Caton-Deschamps indexes were significantly lower in the operated extremity than in the healthy limb at last follow-up. No association was demonstrated between AKP and nail position in relation to the anterior tibial cortex or tibial plateau. According to our study, although the patellar tendon shortened significantly on the affected side compared with the contralateral side, these measurements did not correlate with the presence or absence of pain. AKP and functional knee scores after tibia IM nailing using a transtendinous approach were not associated with nail position in relation to the anterior tibial cortex or tibial plateau. Level 3 (Case control study).

Effects of fat pad excision on length of the patellar tendon after total knee replacement

PurposeWe report our results of the effect that total fat pad excision has on patellar tendon length following total knee replacement. MethodWe retrospectively reviewed radiographs of the knees of 133 patients who had Depuy LCS uncemented TKR between January 2009 to December 2009. We excluded patients who had patella resurfacing, lateral release, knee replacement for other than osteoarthritis and who had other implants used. We measured the length of the patellar tendon using the Insall-Salvati ratio.. Changes in the length of the tendon were calculated both as an absolute evaluation and as a percentage of the original length. ResultsWe effect of fat pad excision on patellar tendon length at 1 year and 5 years following surgery. At one year we observed no change in patellar tendon length in 81.1%, patella infera in 17.3% and patella alta in 1.6% of these 133 patients. We manage to follow up 50 of these patients at 5 years following surgery. In comparison to pre-operative length, at one year 86% showed no change, 14% had patella infera and none had patella alta. At 5 years we observed no change in 98% and patella infera in 2% of patients.Forty nine percent of our patients with patella infera developed anterior knee pain, mean flexion in those patients was 95.625° and mean oxford score was 52.31. ConclusionsIn our patients following single implant design used patella infera developed in up to 18% at one year following surgery. Two percent of fifty patients who had five years follow up showed further shortening of patellar tendon after one year. We conclude that complete fat pad excision during total knee replacement does affect patellar tendon length.Level of evidence IV.

High Tibial Valgus Osteotomy: Closing, Opening or Combined? Patellar Height as a Determining Factor

BackgroundAccording to the literature, closing and opening wedge high tibial valgus osteotomies can raise or lower the patella, and diffèrent methods of patella height measurement show similarly conflicting results. Clarification of this was thought to be important because there is much literature describing morbidity secondary to patella alta or patella infera (baja). Effects on tibial slope and patellar tendon length are not well delineated and the influence of sex and age is unknown.Questions/purposeA group of patients who underwent high tibial valgus osteotomy was investigated to determine how surgical technique influenced postoperative (1) patellar height and (2) tibial slope and patellar tendon length, and (3) whether age or gender independently influenced postoperative patellar height. To eliminate the often conflicting results seen when several ratio methods are used, patellar height was measured by one method, before and after surgery, shown previously to be reliable.MethodsPatellar height was measured on radiographs using the plateau-patella angle in a retrospective case series consisting of three cohorts: 18 patients with closing wedge osteotomies, 26 with opening wedge osteotomies, and 32 with combined osteotomies. The indication for surgery in all three cohorts was medial osteoarthritis with secondary varus. Before surgery there were no significant differences in patellar height, femorotibial angle, age, or gender among the three groups, and no patients were lost to followup during the 8-week study period after surgery. Seven of the 76 patients (9.2%), all in the opening wedge cohort, had concomitant ACL reconstruction at the time of the tibial osteotomy. No other surgery, except arthroscopy, was performed at the time of osteotomy. Patellar tendon length was assessed by the Insall-Salvati index and tibial slope by the angle between the posterior tibial cortex and the medial tibial joint line. Postoperative measurements were made between 6 and 8 weeks. The influence of sex and age was calculated using patellar height measurements made before any surgery.ResultsAll closing wedge osteotomies produced patellar ascent by an average of 13% (p < 0.001), all opening wedges produced descent by an average of 21% (p < 0.001), and the combined osteotomy mean showed minimal change (p = 0.0034). The absolute consistency of the changes and their direction allow suggested guidelines for selection of osteotomy type. There were only slight changes in tibial slope. A significant change in patellar tendon length was seen in seven knees of the opening wedge cohort that had concomitant ACL reconstruction. All had a mean reduction of the Insall-Salvati index of 0.05 (approximately 5%), p = 0.0002. New findings showed higher patellae in female and older patients, unrelated to the surgery.ConclusionsIf it is accepted that patella baja and patella alta should be avoided, then closing wedge osteotomies should be performed only when the patella is low riding, and opening wedge osteotomies should be done only for patients with preexisting patella alta. The combined osteotomy minimizes changes in patellar height. Patellar tendon contractures and tibial slope changes can be avoided. The plateau-patella angle should be measured preoperatively to help decide the type of osteotomy.Level of EvidenceLevel III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Patellar Tendon Tenodesis in Association With Tibial Tubercle Distalization for the Treatment of Episodic Patellar Dislocation With Patella Alta

Background: The association between patella alta and episodic patellar dislocation (EPD) has been well described, but its pathophysiology is not completely clear. Patella alta causes decreased contact between the patella and trochlea and decreased resistance to lateral translation of the patella. Additionally, increased patellar tendon length may allow pathologically increased coronal plane patellar motion. It may thus be desirable to address the length of the patellar tendon itself rather than just its insertion site. Hypothesis: Tenodesis of the patellar tendon in association with tibial tubercle distalization in patients with EPD and abnormally long patellar tendons (>52 mm) results in significant reduction in patellar tendon length, prevention of further patellar dislocation, and good knee function at long-term follow-up. Study Design: Case series; Level of evidence, 4. Methods: Twenty-seven knees in 22 patients with EPD and patella alta were treated with patellar tendon tenodesis and tibial tubercle distalization. Following tubercle distalization, the patellar tendon was tenodesed into the original location of the tibial tubercle with suture anchors. Changes in patellar tendon length and patellar height were measured radiographically. Any recurrent dislocation was documented, and patients completed an International Knee Documentation Committee (IKDC) subjective form at a mean of 9.6 years (range, 6-14 years) after surgery. Results: The mean length of the patellar tendon decreased from 56.3 ± 2.7 mm to 44.3 ± 8.6 mm (P < .0001). The Caton-Deschamps index decreased from 1.22 ± 0.17 to 0.95 ± 0.22 (P < .0001), and the Insall-Salvati ratio decreased from 1.42 ± 0.17 to 0.91 ± 0.18 (P < .0001). No patellar dislocations occurred postoperatively. The mean postoperative subjective IKDC score was 75.6 ± 9.5. Conclusion: Patellar tendon tenodesis and tibial tubercle distalization result in normalization of patellar tendon length, a stable patellofemoral joint, and good long-term knee function in patients with patella alta and EPD.

Patellar Tendon Length After Knee Arthroplasty With and Without Preservation of the Infrapatellar Fat Pad

Our aim was to assess whether there was any significant difference in change in patellar tendon length after knee arthroplasty, when the infrapatellar fat pad was either preserved or excised. Three-year radiographic follow-up was studied on 73 primary knee arthroplasty patients. The infrapatellar fat pad was completely preserved in 38 cases and completely excised in 35. At 3 years there was a significant patellar tendon shortening of 4.2% ( P = .0004) in the fat pad excision group and no significant change in the fat pad preservation group ( P = .82). The difference between the 2 groups was significant ( P = .004). Our results show that patella tendon length does not always shorten after knee arthroplasty and that preservation of the infrapatellar fat pad may be a factor in preventing such shortening.

Patellar tendon length after anterior cruciate ligament reconstruction: a comparative magnetic resonance imaging study between patellar and hamstring tendon autografts

Patellar tendon shortening after anterior cruciate ligament reconstruction may be associated with anterior knee pain or patellofemoral arthritis. The present study was designed to compare postoperative changes in patellar tendon length after anterior cruciate ligament reconstruction between patellar tendon and hamstring tendon autograft. Magnetic resonance images of both knees (operated and healthy) and functional outcome were documented at least 1 year postoperatively in 16 patellar tendon harvested patients and in 32 hamstrings harvested patients. Patellar tendon length, patella length and Insall-Salvati ratio were measured. The operated knee values were compared to the respective values of the non-operated control knees. A significant 4.2 mm or 9.7% patellar tendon shortening in patellar tendon group and a non-significant 1.14 mm or 2.6% shortening in hamstrings group was detected. No significant difference was detected in terms of major shortening-patella baja-(6% for the patellar tendon group vs. 0% for the hamstring group). There was no significant difference in anterior knee problems between the two groups as evidenced by the Shelbourne score (94 for the patellar tendon group vs. 98 for the hamstring group). Harvesting of the patellar tendon for anterior cruciate ligament reconstruction resulted in a significant shortening of the remaining tendon. In contrast harvesting of the hamstring tendons did not affect significantly the patellar tendon length. However, the incidence of patella baja and overall functional outcome was not significantly different between the two groups.

Length of the patellar tendon after anterior cruciate ligament reconstruction with patellar tendon autograft: A prospective clinical study using roentgen stereometric analysis

Purpose: This prospective study was designed to assess postoperative changes in patellar tendon length after removal of its central one third for anterior cruciate ligament (ACL) reconstruction using precise Roengen stereometric analysis (RSA). Type of Study: Prospective clinical study. Methods: Ten consecutive patients underwent arthroscopically assisted ACL reconstruction using the mid-third bone–patellar tendon–bone (BPTB) autograft. The tendon defect was left open and the paratenon was approximated with sutures. Tantalum beads were inserted in the distal part of the patella and in the tibial tuberosity through the bone defects. The distance between the tantalum markers in the patella and the tibial tuberosity was measured with RSA at the first day and at 1, 2, 3, 6, and 12 months after surgery. Results: A decrease of patellar tendon length was observed in all cases. The amount of shortening averaged 1.6 mm (range, 0.5 to 3.2 mm), 3.2% of the initial length. In 4 patients, tendon shortening was detected during the first 4 weeks after surgery. In 6 cases, decrease of patellar tendon length started between the fourth and the eighth week. The shortening process continued in 8 knees until the 12th week. No further changes in patellar tendon length were observed after the 12th postoperative week. In 2 patients, shortening of the patella tendon exceeded 2 mm. The amount of patellar tendon shortening was not related to anterior knee pain. Conclusions: After removing the BPTB autograft, irreversible shortening of the remaining two thirds of the patellar tendon occurred during the first 12 postoperative weeks.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 8 (October), 2002: pp 859–864

Patellar tendon length after anterior cruciate ligament reconstruction

We studied changes in patellar tendon length after reconstruction of the anterior cruciate ligament using either the medial third of the patellar tendon as a graft (n = 40) or a Leeds-Keio artificial ligament (n = 40). Both types of ligament replacement had been supplemented with a MacIntosh extra-articular lateral substitution. The mean change in length in the tendon graft group was 6% (SD 5.39); in the Leeds-Keio group it was 2.4% (SD 4.93). The change in length was significant in both groups, but shortening was more frequent and more severe in the tendon graft group. There was shortening of 10% or more in 25% of knees after patellar tendon graft and 7.5% after use of a Leeds-Keio prosthesis.