Medial Retinaculum Research Articles

Strengthening of the patellofemoral ligament by rivet fixation of the dissociative semitendinosus tendon for recurrent patellar dislocation

Objective To investigate therapeutic effects of rivet fixation of the dissociative semitendinosus tendon to strengthen the patellofemoral ligament for management of recurrent patellar dislocations.Methods From March 1999 to January 2008, 57 cases of recurrent patellar dislocation were treated in our department. They were 19 males and 38 females, with an average age of 24. 3 (range, 17 to 29) years.Their disease courses ranged from 1 to 4 years (average, 2.6 years) . Of them, 15 (group A) were treated with repair of the medial retinaculum and patellofemoral ligament, 19 (group B) with reconstruction of the medial patellofemoral ligament, and 23 (group C) with rivet fixation of the dissociative semitendinosus tendon to strengthen the patellofemoral ligament. All the patients were followed up in the out-patient department 12months later. Functional recovery was evaluated by the Lysholm scores and the Insall evaluation. Results There were statistical significant differences between the preoperative and postoperative Lysholm scores in the 3 groups respectively. Group C had a comparable therapeutic effect with group B( P > 0. 05) . The postoperative Lysholm score for group C was significantly higher than that for group A ( P 0. 05 ) . Conclusion For recurrent patella dislocations, rivet fixation of the dissociative semitendinosus tendon to strengthen the patellofemoral ligament can be as effective as the traditional medial patellofemoral reconstruction, but it is simpler and less invasive and may reduce the risk of patellar fracture. Key words: Patellar dislocation; Patellofemoral ligament; Reconstructive surgical procedures

Medial Patellofemoral Ligament Reconstruction: Docking Technique

The management of patellar instability has advanced with an improved understanding of the critical role of the medial patellofemoral ligament (MPFL), along with the development of novel techniques for ligament reconstruction. The docking technique for MPFL reconstruction offers several technical advantages, including anatomically accurate reconstruction, ease of confirmation of graft isometry, and simplicity of graft tensioning and fixation. Biomechanically, the femoral fixation provides a combined interference screw and suture anchor construct. Imbrication of the vastus medialis obliquus (VMO) and medial retinaculum contributes additional dynamic support to the medial soft-tissue reconstruction. The docking technique offers a simplified and accurate approach to MPFL reconstruction, with consistently favorable postoperative results in the management of patellar instability.

Extraarticular Knee Resection for Sarcomas with Preservation of the Extensor Mechanism: Surgical Technique and Review of Cases

Sarcomas in or contaminating the knee are rare but extremely challenging to treat. Complete resection of the joint is necessary, and often the entire extensor mechanism is removed as well. Reconstruction of the knee is challenging, and the resulting function may be compromised. We describe a surgical technique of extraarticular resection of the knee while preserving the extensor mechanism combined with prosthetic reconstruction. The medial and lateral retinaculum is prepared such that it allows extraarticular placement of K-wires that are driven through the patella and the proximal tibia, serving as in situ guides for the osteotomies. We retrospectively reviewed 11 patients with sarcomas contaminating the knee. The minimum followup was 14 months (mean, 38 months; range, 14-80 months). At last followup patients had a mean flexion of 88° (range, 65°-120°). We observed no complications related to the extensor mechanism, and there was one local recurrence. We believe extraarticular resection of the knee with preservation of the extensor mechanism is a reasonable treatment option for intraarticular sarcomas with functional scores comparable to those for patients having intraarticular resections. Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The management of patella infera in current practice

Patella infera described by Caton et al.The measurement is made in 1982 is an accompanying symptom in certain knee affections secondary to the abnormal situation of the patella. The measurement is made on the X-ray with sagittal view after measuring the patellar height, using the original technique described by the author, when the ratio between the articular surface of the patella and the distance form the patellar tip to the tibial tubercle. Indications of surgery may be when this ration is inferior or equals 0.6. The origin of the patella infera can be mechanical or inflammatory. The operative technique addresses the etiology. In current practice, the patellar height and the patellar tendon length may be evaluated using a sagittal section MRI. In the authors’ experience, when the Caton ratio is lower or equals 0.6 and when the length of the patellar tendon is over 25 mm, the indication of surgery includes proximal transfer of the tibial tubercle. If the length of the patellar tendon is less than 25 mm, it is often necessary to perform a patellar tendon lengthening (PTL). This type of surgery is contraindicated in the authors’ experience in depressive or pusillanimous subjects. The two surgical techniques are described. Both techniques use an anterior and medial approach. The proximal transfer of the tibial tubercle (PTT) includes medial and lateral retinaculum release. The tibial tubercle is detached and transferred upwards according to the pre-operative planning generally 1 or 2 cm and is fixed with 2 screws. PTL includes a medial and lateral retinaculum release often with the fat pad. The patellar tendon is dissociated in the middle over its whole length, and the medial pad is detached of the tibial tubercle and the lateral of the patella. After lengthening, the edges of the tendon are sutured, and this suturing reinforced. Alternative procedures may be used when PTT or PTL are not possible, using transplantation with an allograft of the extensor system or a plasty with hamstring muscles.

The type V bone contusion of knee: MRI diagnosis and clinical significance

Objective To explore the MRI appearances of type Ⅴ bone contusion of knee, and explore the diagnostic value and clinical significance of MRI. Methods A retrospective review of 1672 consecutive MRI examinations of acutely injured knees was performed to screen patients with type Ⅴ bone contusion. The MRI findings of them were analyzed by two musculoskeletal radiologists. Results The type Ⅴ bone contusion of knee was found in 43 (2.6%)patients, involving both the inferomedial patella and the anterolateral femoral condyle. Bone contusion was defined as low signal on T_1WI, intermediate or slight hypointense signal on T_2WI,and high signal intensity on fat saturation PDWI, which could be easily detected on axial, sagittal or coronal MR images. Other concomitant specific MR findings included fracture in 9 patients, chondral injury in 29 patients, and lateral patellar subluxation or complete dislocation in 27 patients. Injury of the medial retinaculum was diagnosed and classified in 37 cases, which could be observed best on axial images. Conclusions MRI was accurate in detecting the type Ⅴ bone contusion and that is very helpful for diagnosis and treatment of transient lateral patellar dislocation,and should be used as a routine examination for knee trauma. Axial MR examination should be performed to evaluated the medial patellar retinaculum injury when type Ⅴ bone contusion was found. Key words: Knee joint; Wounds and injuries; Magnetic resonance imaging

Treatment of a Neglected Displaced Transverse Patella Fracture

A case of a displaced transverse fracture of the patella untreated for 2 years in a 67-year-old woman is presented. The patient requested treatment for giving way of the knee. Surgery included mobilization of the proximal fracture fragment, fixation with two cannulated screws, and repair of the medial retinaculum. The lateral retinaculum was left open to provide for better motion. At 1 year postoperatively, she ambulated with a cane, with range of motion examination revealing 5 degrees flexion contracture and 80 degrees flexion.

Die operative Behandlung von Streckdefiziten am Kniegelenk

Restoration of full knee extension in patients with chronic extension deficits, especially in posttraumatic and postoperative cases. Chronic knee extension deficits of more than 10 degrees . Local intraarticular problems caused by cyclops syndrome, graft hypertrophy or graft impingement after anterior cruciate ligament reconstruction (notch impingement). These patients should be treated with arthroscopic procedures. Spastic flexion contracture. Noncompliant patients. Acute or chronic infections. Poor soft-tissue conditions on site of surgery. If necessary, arthroscopy before arthrolysis to assure that the extension deficit is not caused by a local problem (cyclops, osteophytes, graft hypertrophy or graft impingement after anterior cruciate ligament reconstruction). Anterior skin incision at the medial border of the patellar ligament. Resection of Hoffa's fat pad, which is extremely fibrotic in almost all cases. Second skin incision at the posteromedial side of the knee joint. Incision of the medial retinaculum between the posterior border of the medial collateral ligament and the posterior oblique ligament. Posteromedial arthrotomy between the distal part of the tendon of the adductor magnus muscle and the posterior horn of the medial meniscus. Release of all adhesions in the posterior recess of the knee joint. Complete release of the posterior joint capsule from the femoral shaft. Immobilization for 48 h after surgery in full extension (no knee motion allowed in the first 48 h). For 48 h after surgery only short walks to the bathroom are allowed. Special dynamic extension brace (Dynasplint((R)), CDS((R)) Forte, Albrecht company, Stephanskirchen, Germany) for 4-6 weeks after surgery 6-8 h per day. Painkillers following WHO (World Health Organization) protocol. Manual lymph drainage and electric muscle stimulation help to decrease pain and swelling. Physiotherapy twice daily starting at the 2nd postoperative day. No flexion exercises for the first 7 days after surgery. 15 kg partial weight bearing for 4-6 weeks. Daily physiotherapy is recommended after discharge. 121 patients underwent anterior and posterior arthrolysis between 1990 and 2000. 86 of these patients could be included in this study. The average follow-up was 4.6 years (1-10 years). The extension deficit before surgery averaged 20 degrees compared with the opposite side. At follow-up, the average extension had increased by 17 degrees , no patient had more than 5 degrees of flexion contracture. The Lysholm Score was 84 postoperatively. The Tegner Activity Scale increased from 1.9 to 4.0 after arthrolysis. In the AOSSM Subjective Outcome Score, 35 patients showed excellent and 60 good results. 14 patients were satisfied after surgery and nine were not. Three patients required revision surgery (two synovial fistulas, one hematoma).

The Anatomy of the Medial Patellofemoral Ligament

Background Fibrous connections and fibrofatty tissue between the layers of the medial retinaculum have prevented accurate definition of the true anatomy of the medial patellofemoral ligament. This has led to confusion about the origin, form, course, and insertion of this structure. Hypothesis The medial patellofemoral ligament is a discrete structure that can be approached, isolated, and definitively described. Study Design Descriptive laboratory study. Methods Fifty fresh or fresh-frozen human knee specimens were carefully dissected to determine the precise anatomy of the medial patellofemoral ligament. Results Present in all specimens, the medial patellofemoral ligament was found to have 2 origins: (1) a transverse 10.6-mm origin from the bony groove between the medial epicondyle and the adductor tubercle, and (2) an oblique decussation originating from the proximal 30 mm of the leading edge of the superficial medial collateral ligament. The 2 origins combined and inseparably joined the vastus medialis obliquus tendon and inserted securely into the ventral edge of the bony patella over a span of 28.2 ± 5.6 mm adjacent to the articular surface of the patella. The length from the femoral origin to the patella was 59.8 ± 4.8 mm. The key to the dissection was finding the fine capsular vessels from the descending genicular artery that is between layers I and II of the medial retinacular structures. Conclusion The medial patellofemoral ligament is a constant structure in la‡yer II, with a complex anatomy that can be defined by careful dissection using the capsular branches of the descending genicular artery as a guide. Clinical Relevance This study provides essential new information that could help surgeons safely locate the medial patellofemoral ligament and repair or reconstruct it anatomically.

Abstract: P196 CHANGES IN THE STRUCTURE OF AORTAS IN RATS WITH METABOLIC SYNDROME DURING AGING

In a total of 15 knees from 15 patients undergoing medial patellofemoral ligament reconstruction using an artificial substitute and a medial retinaculum slip coverage for recurrent patellar dislocation, the reconstructed ligaments were histologically evaluated using hematoxilin-eosin and elastic van Gieson stains. The artificial substitute was a mesh-type Leeds–Keio ligament. The mean age of the patients at the time of surgery was 20 years (range; 13–38 years). The mean interval from initial reconstruction to gathering was 53 months (range; 11–109 months). In the tissue over the artificial ligament, longitudinally aligned collagen fiber bundles with spindle-shaped nuclei were formed in all specimens except one specimen of 11 months postsurgery, but it seemed to be mature ligament only in specimens more than 60 months postsurgery. The tissue inside the artificial ligament was immature as a whole in all specimens, although 13 out of the 15 specimens had regularly aligned collagen fiber bundles slightly or in some portions.

Sportfähigkeit nach Patellaluxation

A dislocation of the patella is a serious injury which can far affect the career of every athlete or even finish it. In a retrospective study we examined 24 athletes (mean age 19.3 years, post surgical observation period 39 (13 to 79) months) which suffered from a patellar dislocation and received arthroscopic surgical treatment. The diagnostics contained clinical investigation and X-rays of the knee joint in 2 plains as well as patella tangential, in pathological axial deformations of the leg completed with whole-leg-images and optional a torsion computed tomography. All 24 patients received an arthroscopical assisted suturing of the medial retinaculum, in 12 patients additional a lateral release was carried out. The postoperative course followed a standard pattern. In 24 operated patients the reoccurrence rate was 12.5 % (3 patients), which is within the range of the latest published figures (average 12.0 %). The Lysholm score was in 15 (62.4 %) of all patients higher than 80 demonstrating the good to very good results, the average Lysholm score was 83.4. Out of 24 patients with patellar dislocation 11 patients (45.8 %) were able to continue their sport career after surgical therapy at the pre-trauma level, 4 patients (16.6 %) had to continue at lower level, 9 patients (37.5 %) had to finish their sport career. The Tegner activity score decreased from 7.2 to 6.0 at about 1.2 points what means a clear decrease of the activity level. On average a full sportive level was reached 9.7 months after surgery. Especially sport athletes needs to be informed about the seriousness of the injury and the long process of rehabilitation.

Mini-Subvastus-Zugang bei der Implantation von Knieendoprothesen

Total knee replacement in minimally invasive technique without any trauma to the extensor apparatus and with soft-tissue-referenced bone resections. Only the subvastus approach preserves the integrity of the extensor apparatus and has therefore been modified to become a minimally invasive technique with a shorter skin incision and lateralization instead of eversion of the patella. Soft-tissue balancing is done through this direct anterior approach. Mild to moderate varus osteoarthritis of the knee up to 15 degrees of malalignment, mild and passively correctable valgus osteoarthritis of the knee up to 10 degrees of malalignment. Severe, contract varus osteoarthritis of the knee, severe and moderate, contract valgus osteoarthritis of the knee, severe obesity, exceptionally muscular patients, decreased skin perfusion. Central skin incision from the superior pole of the patella to the tibial tubercle. Exposure of the medial retinaculum and mobilization of the vastus medialis muscle subcutaneously. Incision of the medial retinaculum and blunt separation of the vastus medialis muscle from the intermuscular septum. Lateralization of the patella and flexion of the knee joint. Resection of the tibia perpendicular to the diaphysis. Adjustment of the anteroposterior (AP) resection block at the level of the anterior femoral cortex and of rotation by applying equal tension to the collateral ligaments. Balancing of soft-tissue tension in flexion gap by release, if necessary. After AP resection fixation of distal resection block in planned valgus angle. Balancing of soft-tissue tension in extension gap by release, if necessary. After distal femur resection facet resection, adaptation of posterior femoral condyles, and implantation of prosthesis. Check on stability and range of motion. Wound closure. Full weight bearing from the 1st postoperative day, CPM (continuous passive motion) with up to 90 degrees flexion with peridural anesthesia as tolerated, stair climbing starting on the 7th postoperative day. 100 patients were randomized to total knee replacement via a parapatellar or subvastus approach. Radiologically, there were no differences in operative precision or leg alignment. Patients treated minimally invasively suffered less pain and achieved a higher flexion of 110 degrees versus 95 degrees 6 weeks postoperatively. However, there were two cases of delayed wound healing in this group. The surgical technique is demanding and the operating time is longer. Long-term results are still missing.

Treatment with and without Initial Stabilizing Surgery for Primary Traumatic Patellar Dislocation

There is no consensus about the management of acute primary traumatic patellar dislocation in young physically active adults. The objective of this study was to compare the clinical outcomes after treatment with and without initial stabilizing surgery for primary traumatic patellar dislocation in young adults. Forty young adults, thirty-seven men and three women with a median age of twenty years (range, nineteen to twenty-two years), who had an acute primary traumatic patellar dislocation were randomly allocated to be treated with initial surgical stabilization (eighteen patients, with each receiving one of two types of initial stabilizing procedures) or to be managed with an orthosis (twenty-two patients, including four who had osteochondral fragments removed arthroscopically). After a median of seven years, thirty-eight patients returned for a follow-up examination. Redislocations, subjective symptoms, and functional limitations were evaluated. Radiographs and magnetic resonance images were obtained at the time of randomization, and twenty-nine (76%) patients underwent magnetic resonance imaging at the time of final follow-up. A hemarthrosis as well as injuries of the medial retinaculum and the medial patellofemoral ligament were found on magnetic resonance imaging in all patients at the time of randomization. During the follow-up period, six of the twenty-one nonoperatively treated patients and none of the seventeen patients treated with surgical stabilization had a redislocation (p = 0.02). Four nonoperatively treated patients and two patients treated with surgical stabilization reported painful patellar subluxation. The median Kujala scores were 91 points for the surgically treated patients and 90 points for the nonoperatively treated patients. Thirteen patients in the surgically treated group and fifteen in the nonoperatively treated group regained their former physical activity level. At the time of follow-up, a full-thickness patellofemoral articular cartilage lesion was detected on magnetic resonance imaging in eleven patients; the lesions were considered to be unrelated to the form of treatment. In a study of young, mostly male adults with primary traumatic patellar dislocation, the rate of redislocation for those treated with surgical stabilization was significantly lower than the rate for those treated without surgical stabilization. However, no clear subjective benefits of initial stabilizing surgery were seen at the time of long-term follow-up.

Using an iliotibial tract for patellar dislocation in children

To evaluate the clinical and functional results of surgical treatment of patellar dislocation in children. A prospective study was undertaken from January 1995 to December 2004. Patients who suffered from patellar dislocation after receiving intramuscular antibiotic injections to quadriceps were recruited. A complete history of each patient was recorded, and both a clinical and a roentgenographic examination were performed preoperatively. Patellar dislocation was classified according to Bensahel's criteria. The iliotibial tract and lateral retinacula was released to restore the tension of the medial retinaculum. Quadricepsplasty was used in all patients for full flexion of knee. There were nine males and 65 females in this study. All 74 patients (76 knees) developed dislocation of the patella after repeated intramuscular injections of antibiotic(s) into the quadriceps muscle. Fifty-six knees (73.7%) were type 1, and 20 knees (26.3%) were type 2 (Bensahel's classification). In all, we attained excellent results in 56 knees (73.7%), good results in 17 knees (22.4%), and fair results in three knees (3.9%). There have been no poor results or recurrences so far. Use of the iliotibial tract, adequate lateral retinacular release, restoration of the tension of the medial retinaculum and associated quadricepsplasty achieved a high success rate. The technique is simple, safe and effective in skeletally immature children.

Knee Injury-Football

HISTORY: A 17 y.o. offensive lineman on a Div. I football team sustained a knee injury during practice. The patient was blocking in open field when the back of his extended planted leg was struck lightly. He stated "it felt like my knee cap shifted." He was removed for evaluation. PMH: One year h/o intermittent anterior knee pain that was worse during high school basketball. Pain subsided then returned during summer workouts for football 6 weeks prior to acute injury. Normal x-ray. Dx. with quadriceps tendonitis. Placed on modified activity with eccentric strengthening, quad stretching, and NSAIDS for 2 weeks prior to acute injury. PHYSICAL EXAMINATION: Exam on Field- rapid moderate effusion; marked apprehension to lateral stress of patella with mild pain over medial retinaculum; neg. Lachman, valgus and varus stress; unable to perform McMurray secondary to pain; VMO fired with leg extension Exam in Training Room- persistent patella pain and apprehension with decreased retinacular pain; compression, knee immobilizer with patella support, ice, crutches for non-weight bearing, and pain meds. Exam 24 Hours- large effusion; patella pain laterally with reduced pain over medial retinaculum; mild apprehension, minimal pain over the quadricep tendon; difficulty firing VMO and straight leg lift DIFFERENTIAL DIAGNOSIS: Patella Subluxation Meniscal Tear Fracture - Tibial Plateau, Patella Patella/Quadricep Tendon Tear TEST AND RESULTS: Knee X-ray: Transverse fracture of the patella that appears old with smooth sclerotic edges Review of knee x-ray taken 2 weeks prior: Questionable lucency on the lateral aspect of patella Knee X-ray of left knee: Normal Knee MRI: Acute patella fracture with suspected chondral fragment at the fracture site along the medial retropatellar cartilage; partial tear of the quadriceps tendon; partial tear of the lateral patellar retinaculum; hemarthrosis; no meniscal tear FINAL WORKING DIAGNOSIS: Acute noncontact fracture of transverse bipartite patella TREATMENT AND OUTCOMES: ORIF with bone grafting Repeat x-ray at 5 weeks with union of fracture Clinical outcome pending rehab

An initial qualitative study of dual-energy CT in the knee ligaments

To study the clinical application of dual-energy CT (DECT) in the knee ligaments. Twelve cases (24 knees) were scanned using dual-energy CT for the knee. Two- and three-dimensional images were used for display in all cases by means of multi-planar reformation (MPR) and volume rendering technique (VRT). All images were ranked by two radiologists according to the grade of knee ligament displayed, the definition of edge and attachment points of the knee ligament. The partial ligaments of 24 knees, such as the patellar ligament, fibular collateral ligament, anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) were clearly displayed; the tibial collateral ligament was not satisfactorily displayed. The transversal ligaments, such as lateral patellar retinaculum and medial patellar retinaculum, and the posterior ligament, such as oblique popliteal ligament could not be shown clearly. The dual-energy CT is a new and valuable tool to qualitatively display the main ligaments of the knee.

The effects of trochlear groove geometry on patellofemoral joint stability-a computer model study

The effect of the variation in the femoral groove geometry on patellofemoral joint stability was studied using a two-dimensional transverse plane model with deformable articular surfaces. The femoral and patellar bony structures were modelled as rigid bodies with their profiles expressed by splines. The articular cartilage was discretized into compression springs, distributed along the femoral and patellar profiles, based on the rigid-body spring model. The medial and lateral retinacula were modelled as linear tensile springs, and the quadriceps muscles and patellar tendon as strings with known tension. The anatomical data were obtained from the transverse plane magnetic resonance images of a normal knee flexed at 20 degrees and from the literature. A dynamic analysis approach was employed to solve the governing equations of the model, i.e. three static equilibrium equations of the patella and a constraint equation for each cartilage spring, explicitly. The results of the model suggest that alteration of the sulcus angle from 139 degrees to 169 degrees causes a lateral shift and tilt of less than 3 mm and 4 degrees. This effect increased slightly with increasing total quadriceps force, however, to significantly more than 7 mm and 18 degrees respectively when the medial retinaculum was released. It was suggested that this might be the combined effect of the medial retinaculum deficiency and trochlear dysplasia that is responsible for patellar subluxation and, particularly, dislocation disorders.

Combined Proximal and Distal Realignment Procedures to Treat the Habitual Dislocation of the Patella in Adults

Background Habitual dislocation of the patella (HDP) is a rare condition. Many surgical procedures using proximal realignment have been reported to treat HDP in children, with around 80% satisfactory results. However, few articles have addressed the treatment of HDP associated with high-grade patellofemoral chondromalacia in adults. Hypothesis A combination of proximal and distal realignment procedures of the patella will reduce pain and increase function in adult patients with HDP. Study Design Case series; Level of evidence, 4. Methods Twelve patients with 13 symptomatic cases of HDP of the knee underwent surgical treatment that included lateral release, medial retinaculum advancement, and the anteromedial tibial tubercle transfer procedure. The average period between dislocation and surgery was 10.8 years. One patient had an additional procedure, an open-wedge varus corrective osteotomy of the distal femur, because of a 20° valgus deformity of the knee. The patellofemoral morphology study included routine and Merchant views of the knee and a computed tomography scan at full extension and at 30° flexion of the knee, before the operation and at follow-up. Any associated intra-articular pathologic findings during the surgical procedure were addressed. Patellofemoral function was evaluated with the Kujala functional score before surgery and at the time of the final follow-up. Results Chondromalacia of the patella over the medial facet and central ridge was grade III in 8 knees and grade IV in 5 knees. Corresponding chondral erosion of the lateral femoral condyle was noted in every knee. All patients were followed for an average period of 67.3 months (range, 25-103 months). The average preoperative Kujala functional score was 43.9 and the average postoperative score was 88.9 (P < .05). Radiographically, there was a statistically significant improvement in the congruence angle from 62.1° ± 15.0° preoperatively to —2.7° ± 9.8° postoperatively (P < .01) and in the lateral patellofemoral angle from —40.2° ± 9.3° preoperatively to 1.4° ± 7.0° postoperatively (P < .01). No patient has reported an episode of patellar dislocation after the surgical procedures. Conclusion Combined proximal and distal realignments of the patella effectively treat HDP in adults with associated high-grade patellofemoral chondromalacia.

MPFL Reconstruction for Recurrent Patella Dislocation: A New Surgical Technique and Review of the Literature

Recurrent dislocation, subluxation and functional instability due to patellofemoral pain might be present in 30 % to 60 % of patients managed non-operatively for posttraumatic patella instability. Disruption of the capsule, medial patella retinaculum and/or vastus medialis obliquus have been associated with recurrent patella instability but recently the medial patellofemoral ligament (MPFL) has been recognised as the most important ligamentous stabiliser preventing lateral dislocation of the patella. Many nonanatomical surgical techniques for the treatment of recurrent patellar dislocation have been described in the literature. These procedures alter the pre-morbid patella mechanics by several principles, including the release of tight lateral ligaments, tensioning of loose medial structures and distal realignment of the extensor mechanism or a combination of these. Very few address the principle site of pathology in patella dislocation, i.e., the torn MPFL. The outcomes are inconsistent and many studies have reported recurrent dislocations and patellofemoral pain and arthritis in up to 40 %. We describe a simple technique of MPFL reconstruction using a single hamstring tendon graft which is passed through the medial intermuscular septum at the adductor's magnus insertion and is fixed to the superomedial pole of the patella. A comprehensive review of the existing techniques of MPFL reconstruction using semitendinosus tendon autografts is also provided.

Total knee arthroplasty by lateral parapatellar approach for valgus knee

To investigate the effect of lateral parapatellar approach in total knee arthroplasty (TKA) of valgus knee. Lateral parapatellar approach of total knee arthroplasty was applied in 8 patients (10 knees) with severe valgus osteoarthritis knee (bilateral in 2 cases and unilateral in 6 cases), with the valgus angle > 15 degrees , 1 male (1 knee) and 7 females (9 knee), aged 68.2 (58 - 79), 7 cases (9 knees) being of the Krackow type I and 1 case (1 knee) of the Krackow type I, I. After incision of the skin through lateral knee, ilio-tibial band was prolonged by apple pie arthroplasty. The joint capsule was cut open laterally 2 - 4 cm from the para-patellar edge. Soft tissue balance was performed by releasing I - T band in Gerdy tubercle, lateral collateral ligament and poster-lateral capsule from the femur and tibial side. Valgus angle of distal femur cutting were five degree. Whiteside line and trans-epicondylar line were used as AP rotational cutting reference. All patellar of the group were resurfaced. Capsule closure is completed with the knee flexed. The expanded deep lateral soft tissue sleeve (coronal Z-plasty) is sutured with the medial retinaculum sleeve (superficial layer). Follow-up was conducted for 19.6 months (1 - 51 months). Seven cases (9 knees) were replaced by posterior stabilized cemented prostheses (TC-Dynamic, PLUS), one case (1 knee) was replaced by RT prosthesis (RT-PLUS(TM) Solution, PLUS). After operation, the valgus deformity of all patients was corrected and all patients could walk 100 m with or without the help of walking holders. The average range of motion (ROM) was improved from the pre-operative. 95.6 degrees (85 degrees - 110 degrees ) to the post-operative 117.1 degrees (100 degrees - 125 degrees ). The average femorotibial angle (FTA) was corrected from the pre-operative. 27.6 degrees (20 degrees - 40 degrees ) to the post-operative 6.8 degrees (5 degrees - 9 degrees ). The Knee Score System (KSS) score and functional score were improved from the pre-operative 22.7 points (9 - 48 points) and 26.5 points (12 - 55 points) to the post-operative 86.4 points (85 - 95 points) and 89.1 points (80 - 95 points) respectively. Follow-up showed that the FTA remained unchanged and the knee stability of all patients was good. Through lateral approach, "Z" plasty of the capsule can release the lateral structure and decrease the pressure of common peroneal nerve. For TKR with moderate to severe fixed valgus knee, lateral approach is an effective way to correct the deformity.

Dynamic measurement of patellofemoral kinematics and contact pressure after lateral retinacular release: an in vitro study

The purpose of this study was to investigate the influence of lateral retinacular release and medial and lateral retinacular deficiency on patellofemoral position and retropatellar contact pressure. Human knee specimens (n = 8, mean age = 65 SD 7 years, all male) were tested in a kinematic knee-simulating machine. During simulation of an isokinetic knee extension cycle from 120 degrees to full extension, a hydraulic cylinder applied sufficient force to the quadriceps tendon to produce an extension moment of 31 Nm. The position of the patella was measured using an ultrasound based motion analysis system (CMS 100, Zebris). The amount of patellofemoral contact pressure and its pressure distribution was measured using a pressure sensitive film (Tekscan, Boston). Patellar position and contact pressure were first investigated in intact knee conditions, after a lateral retinacular release and a release of the medial and lateral retinaculum. After lateral retinacular release the patella continuously moved from a significant medialised position at flexion (P = 0.01) to a lateralised position (P = 0.02) at full knee extension compared to intact conditions, the centre of patellofemoral contact pressure was significantly medialised (0.04) between 120 degrees and 60 degrees knee flexion. Patellofemoral contact pressure did not change significantly. In the deficient knee conditions the patella moved on a significant lateralised track (P = 0.04) through the entire extension cycle with a lateralised centre of patellofemoral pressure (P = 0.04) with a trend (P = 0.08) towards increased patellofemoral pressure. The results suggest that lateral retinacular release did not inevitably stabilise or medialise patellar tracking through the entire knee extension cycle, but could decrease pressure on the lateral patellar facet in knee flexion. Therefore lateral retinacular release should be considered carefully in cases of patellar instability.