Pes Anserinus Tendons Research Articles

Surgical Repair of Stener-like Lesion of the Medial Collateral Ligament of the Knee

Introduction: Superficial medial collateral ligament (sMCL) tears of the knee will usually be treated non-surgically. But in some cases such as those with tears at the distal insertion, where it may displace over the pes anserinus tendons (Stener-like lesion), surgery will be performed. Here, we describe a patient with acute traumatic Stener-like lesions of sMCL based on clinical evaluation and imaging results, who underwent primary surgical repair. Case Presentation: A 26 years old male patient was admitted to the outpatient clinic with a chief complaint of left knee pain after valgus trauma on the left knee while playing badminton 5 days prior. Clinical examination revealed a moderate swelling and there was tenderness on the medial joint line. The full knee flexion was restricted due to swelling. A valgus stress test showed laxity of the medial joint. The anterior drawer and Lachman test showed anterior laxity. A left knee joint aspiration was done and 45 cc of red cloudy synovial fluid was aspirated. On the MRI examination, a bunched MCL with a displacement of the tibial insertion site over the per anserinus tendons was identified, along with the complete rupture of the ACL. The patient underwent two-stage treatment : an arthroscopic ACL reconstruction and surgical repair of the MCL. After the surgery, the patient wore a knee brace fixed in full extension for 4 weeks. The patient also followed a standard ACL rehabilitation protocol. Follow up were done 6 months after the surgery. Results: At final follow-up, the patient had regained normal stability of the MCL without any laxity in comparison to the contralateral knee. The anterior drawer and Lachman test had returned to normal. Patient was completely pain-free and did not have any complaints of instability. Discussion: Surgical repair is indicated in specific circumstances such as a Stener-like lesion in which the interposition of the pes anserinus between the ligament impeding the healing process of MCL. Prompt surgical intervention can restore the anatomic position of the MCL, promote anatomic healing, and prevent long-term valgus instability. Conclusion: Stener-like lesion of the MCL are rare, and early diagnosis is important in treating this condition. Surgical treatment must be done to provide complete healing of the MCL.

The AIUM Practice Parameter for the Performance of the Musculoskeletal Ultrasound Examination.

The AIUM Practice Parameter for the Performance of the Musculoskeletal Ultrasound Examination.

Radiofrequency Ablation of the Infrapatellar Branch of the Saphenous Nerve for the Treatment of Chronic Anterior Inferomedial Knee Pain.

Genicular nerve radiofrequency ablation (GNRFA) is an effective treatment for chronic knee pain related to osteoarthritis. It is often utilized when conservative management has failed and patients wish to avoid arthroplasty, are poor surgical candidates due to comorbid medical conditions, or in those suffering from persistent pain after arthroplasty. The classic targets for GNRFA include the superior lateral genicular nerve, superior medial genicular nerve, and inferior medial genicular nerve but multiple anatomic studies have demonstrated additional sensory innervation to the knee. In this research article, we propose an image-guided technique that can safely target the infrapatellar branch of the saphenous nerve which also provides sensory innervation to the anterior capsule. The proposed technique includes variations for conventional bipolar radiofrequency ablation, cooled radiofrequency ablation, dual-tined bipolar radiofrequency ablation, and monopolar radiofrequency ablation using a long axis approach. The described technique is based on updated anatomic studies and takes into account safety concerns such as thermal risk to the skin and/or pes anserine tendons and breaching of the synovial cavity. Future clinical research should be performed to confirm the safety and effectiveness of this specific approach.

EARLY DIAGNOSIS AND PRIMARY REPAIR OF A RARE INJURY OF SUPERFICIAL MEDIAL COLLATERAL LIGAMENT OF KNEE: STENER-TYPE LESION

Introduction: Medial Collateral ligament (MCL) is the primary stabilizer of knee joint against valgus stress force. Sprains of MCL are fairly common due to any injury and are treated conservatively most of the time. These have been classified by Hughston in grades I, II and III based on the severity. While grades I and II mostly have only sprain of the ligament, grade III is complete tears and may warrant surgical correction. Stener-type lesion is a rare finding seen with grade III MCL injuries. Here, superficial MCL (sMCL) tears at its distal insertion and is retracted upwards leading to pes anserinus tendon to lie in between the bed and its distal end. This does not allow the MCL tendon to regain its attachment to bed and needs surgical correction. Material/Methods: We report five patients who presented to us with stener-like lesion. They were then operated with repair of MCL tendon and its reattachment to the Tibial bed using similar techniques. Pre-procedure outcome values (Lysholm score and KOOS score) were evaluated and the patients were followed up for 1 year. At the final follow up, final outcome values were calculated along with complete clinical examination was done. Results: All five patients were fully satisfied and reported no problems in resuming work and daily activities. Clinical evaluation was done and there was reported no joint laxity or opening of joint line with varus/valgus stress conditions. There was a complete range of motion reported in all patients. There was no limping/misalignment or gait disturbances reported at the end of follow up in any of the patients. Conclusion: Stener-type lesion of knee is rare and is needed to be explored further. Our study emphasizes the early diagnosis and surgery with excellent results of cases reported in due course of time. Very limited literature is currently available for this severe sMCL injury. Thus, longer studies involving a larger number of cases and extended follow up are needed in future to explore the ways of early diagnosis and various treatment options further.

CLINICAL AND ULTRASONOGRAPHIC CORRELATION OF PES ANSERINUS BURSITIS

Purpose: Pes anserinus bursitis is a commonly overlooked cause of medial knee pain. It is diagnosed clinically and involves tendons/bursa or both. Majority of studies fail to provide imaging evidence of tendon/bursal pathology in clinically diagnosed patients. This study documents the ultrasonographic findings associated with clinically diagnosed pes anserinus bursitis and correlates between clinical and positive ultrasonographic findings. Methods: A cross-sectional study was done in outpatient department settings of physical medicine and rehabilitation department in participants with clinically diagnosed pes anserinus bursitis. Clinically evaluation was done by Physiatrist and ultrasonographic evaluation by a radiologist. Patient characteristics, clinical findings and ultrasonographic features were documented and studied. Results: In the evaluated 67 knees, Pes anserinus tendonitis (53.73%) with statistical significance ([Formula: see text].0001) was found on ultrasonography over bursitis (2.99%). Abnormal findings involving medial collateral ligament (38.81%), medial meniscus (26.87%), suprapatellar recess (47.76%), and other structures (17.91%) were also documented. Age, gender, body mass index, and duration had no effect on presence of positive ultrasonographic findings. Conclusion: Ultrasonographic changes of tendonitis involving pes anserinus tendons correlate with clinically diagnosed pes anserinus bursitis. The ultrasonography also helps in identifying potential sources of pain other than pes anserinus tendon or bursa in such cases.

Demographic profile and spectrum of ultrasonographic findings in medial knee pain: An observational study

Objectives: Medial knee pain is a common occurrence in people of various age groups with different conditions involving underlying structures. Ultrasound is used in assessing various complex knee pathologies as relying solely on clinical evaluation can be difficult. There are hardly any studies showing the compartmental analysis of knee pain using ultrasound. This study analyses the demographic profile and associated various ultrasonographic findings in patients with medial knee pain. Material and Methods: A cross-sectional study was done with participants of age 18 and above with medial knee pain. Screening was done by a Physical Medicine and Rehabilitation specialist in outpatient department and the ultrasonographic evaluation by a radiologist. Demographic profile and ultrasonographic findings of 46 participants were documented and studied. Results: Out of 46 participants studied, 95.65% were females. The mean age of distribution was 50.61 years and 52% of participants were overweight and 33% with obesity Class-I. Ultrasonography revealed abnormality of medial collateral ligament (45.65%), pes anserine tendon (41.30%) and bursa (4.55%), medial meniscus (36.96%), joint effusion (54.35%), and synovial hypertrophy, Baker’s cyst, and osteophytes. Conclusion: Older age, female gender, and increased body mass index are likely associated with medial knee pain with variable underlying conditions. These conditions can be differentiated with use of ultrasound by visualizing the abnormalities in underlying anatomical structures. Ultrasonography can be used with adequate knowledge and experience as a guide and tool in optimal management of wide spectrum of knee problems.

Diving Pes Anserine Bursal Rupture in a Patient with Knee Osteoarthritis: Case Report

Pes anserine bursitis is not an uncommon pathology especially in the context of knee osteoarthritis; however, ruptured pes anserine bursitis is a rare event. Herein, the authors present a case of diving pes anserine bursal rupture in a patient with knee osteoarthritis who developed postero-medial knee tender swelling. In our case, the bursal rupture was contained, and dived posteriorly, resulting in a cystic calf swelling; the original bursa itself was collapsed beneath the pes anserine tendon, giving a tail-like appearance, such tail-like appearance could help in accurate localization of swelling origin and make the diagnosis of bursal rupture much easier. The tail-like appearance deep to the pes anserine tendon was found to be a helpful imaging feature when assessing cystic calf swelling; it should be kept in mind when pes anserine bursal rupture is a differential diagnostic consideration, as it could indicate the origin of resultant swelling.

Morphological variants of pes anserinus in South India

Background. It was described that variations exist in the pes anserinus tendons. In this study, our aim was to observe the variations of the pes anserinus in South Indians. Methods. We examined 53 embalmed human adult lower extremities. The pes anserinus was macroscopically observed for the morphological variants after dissecting the tendons which inserted at the antero medial surface of proximal tibia. Results. The pes anserinus was formed by 3 tendons, gracilis, semitendinosus and sarto-rius in 48 lower limbs (90.6%). It was observed that, 41 (77.4%) had convergent type, 7 (13.2%) had early convergence and 5 lower limbs (9.4%) were having divergent pattern of pes anserinus morphology.Semimembranosus muscle was taking in the formation of pes anserinus in 3 lower limbs (5.7%). The pes anserinus was inserting into the fascia cruris and not tibia in 8 specimens (15.1%). However in 10 cases (18.9%), the insertion was both at the tibia and fascia cruris.The insertion was only at fascia cruris and not in tibia in 15.1% cases. The semitendinosus was giving an extra slip, which was attaching to the medial condyle of tibia in 7 cases (13.2%). It was giving slip to medial collateral ligament in 2 cases (3.8%) and ligamentum patellae in 1 case (1.9%).Conclusion. We believe that this information about morphological variants of pes anser-inus is helpful to the plastic and orthopaedic surgeons. Preoperative radiological exam-ination of pes anserinus may be helpful to the operating surgeons to avoid the subsequent difficulties during the procedures like transplant surgeries and graft harvesting during reconstructive surgeries.

Anatomical and Morphometric Study of the Pes Anserine Tendons in the Knee

Anatomical and Morphometric Study of the Pes Anserine Tendons in the Knee

Anatomical Repair of Stener-like Lesion of Medial Collateral Ligament: A case Series and Technical Note.

Medial collateral ligament tears usually will be treated through non-surgical methods, but, in some cases such as those with tears at the distal insertion where the reduction could be blocked by the pes anserine tendons (Stener-like lesion), surgery will be performed. Here, we present a surgical technique in such cases. In this retrospective case series, we describe six patients diagnosed with Stener-like lesion based on clinical evaluation and imaging results. In the one-year follow-up visit, there was no complaining of pain or joint instability and full range of motion and negative valgus stress test were reported in all cases. The results showed this surgical technique is a useful and safe treatment approach in such cases.

What Factors Are Associated With Femoral Component Internal Rotation in TKA Using the Gap Balancing Technique?

When using the gap-balancing technique for TKA, excessive medial release and varus proximal tibial resection can be associated with internal rotation of the femoral component. Previous studies have evaluated the causes of femoral component rotational alignment with a separate factor analysis using unadjusted statistical methods, which might result in treatment effects being attributed to confounding variables. (1) What pre- and intraoperative factors are associated with internal rotation of the femoral component in TKA using the gap balancing technique? (2) To what degree does femoral component rotation as defined by the navigation system differ from rotation as measured by postoperative CT? Three hundred seventy-seven knees that underwent computer-assisted primary TKA attributable to degenerative osteoarthritis with varus or mild valgus alignment in which medial soft tissue release was performed, and those with preoperative radiographs including preoperative CT between October 2007 and June 2014 were included in the study. To achieve a balanced mediolateral gap, the structures released during each medial release step were as follows: Step 1, deep medial collateral ligament (MCL); Step 2, superficial MCL (proximal, above the pes anserine tendon) and semimembranosus tendon; and Step 3, the superficial MCL (distal, below the pes anserine tendon). Knees with internal rotation of the femoral component, which was directed by navigation, to achieve a rectangular mediolateral flexion gap were considered cases, and knees without internally rotated femoral components were considered controls. Univariable analysis of the variables (age, sex, BMI, operated side, preoperative hip-knee-ankle angle, preoperative medial proximal tibial angle, preoperative rotation degree of the clinical transepicondylar axis [TEA] relative to the posterior condylar axis [PCA], coronal angle of resected tibia, resection of the posterior cruciate ligament, type of prosthesis, and extent of medial release) of cases and controls was performed, followed by a multivariable logistic regression analysis on those factors where p equals 0.15 or less. For an evaluation of navigation error, 88 knees that underwent postoperative CT were analyzed. Postoperative CT scans were obtained for patients with unexplained pain or stiffness after the operations. Using the paired t-test and Pearson's correlation analysis, the postoperative TEA-PCA measured with postoperative CT was compared with theoretical TEA-PCA, which was calculated with preoperative TEA-PCA and actual femoral component rotation checked by the navigation system. After controlling for a relevant confounding variable such as postoperative hip-knee-ankle angle, we found that the extent of medial release (Step 1 as reference; Step 2: odds ratio [OR], 5.7, [95% CI, 2.2-15]; Step 3: OR, 22, [95% CI, 7.8-62], p < 0.001) was the only factor we identified that was associated with internal rotation of the femoral component. With the numbers available, we found no difference between the mean theoretical postoperative TEA-PCA and the postoperative TEA-PCA measured using postoperative CT (4.8° ± 2.7º versus 5.0° ± 2.3º; mean difference, 0.2° ± 1.5º; p = 0.160). Extent of medial release was the only factor we identified that was associated with internal rotation of the femoral component in gap-balancing TKA. To avoid internal rotation of the femoral component, we recommend a carefully subdivided medial-releasing technique, especially for the superficial MCL because once the superficial MCL has been completely released it cannot easily be restored. Level III, therapeutic study.

Tripled semitendinosus with single harvesting is as effective but less invasive compared to standard gracilis-semitendinosus harvesting.

The anterior cruciate ligament (ACL) reconstruction with pes anserinus tendons has been increasingly used throughout the last years. Although less invasive compared to other autologous grafts, a reduction of internal rotation and flexion strength after gracilis and semitendinosus harvesting has been reported. Harvesting one tendon instead of two from the pes anserinus can reduce the deficit of the knee flexor strength and improve the functional recover without weakening the reconstructed ligament. Forty-five (45) patients who had ACL reconstruction with triple semitendinosus graft (ST3) have been compared with other 45 similar patients who had ACL reconstruction with double gracilis-semitendinosus tendons (GST). Patients have been evaluated at a minimum of 12 months after surgery: IKDC scale, KT-1000, One Leg Hop Test for the objective stability; Isokinetic test for the strength; Tegner scale, Lysholm and IKDC subjective evaluation form for the function. No differences have been detected between the groups for the objective item assessed. Male patients' subjective IKDC score was statistically better for the ST3 group. Recreational soccer players showed a higher Lysholm and subjective IKDC score in ST3 group compared to GST group. There was no difference regarding the return to sport. ST3 guarantees the same objective knee stability compared to a GST. It is a viable option for ACL reconstruction that allows a better preservation of patient's anatomy and a less invasive harvesting surgery. III b, case control study.

Surgical treatment of medial knee ligament injuries: current indications and techniques.

The medial collateral ligament (MCL) and the posterior oblique ligament (POL) are the main static valgus restraints of the knee.Most isolated medial injuries can be treated with bracing and early knee motion.Combined MCL and ACL (anterior cruciate ligament) injuries can be managed with bracing of the knee followed by a delayed reconstruction of the ACL.Residual medial laxity may be addressed at the time of ACL surgery.Bony avulsions, incarceration of the distal MCL under the meniscus or over the pes anserinus tendons, open injuries, MCL tears combined with PCL or bi-cruciate injuries should be treated surgically.Chronic symptomatic medial instability can be managed with the recently described reconstruction techniques using free tendon grafts located at anatomical insertion sites.Cite this article: Tandogan NR, Kayaalp A. Surgical treatment of medial knee ligament injuries: Current indications and techniques. EFORT Open Rev 2016;2:27-33. DOI: 10.1302/2058-5241.1.000007.

Avoiding Anomalous Tendon Harvest at the Pes Anserinus Insertion.

The purpose of this study was to identify the frequency and characteristics of anomalous pes anserinus tendon morphology in an adolescent population undergoing knee anterior cruciate ligament (ACL) reconstruction surgery. The records of all children who underwent ACL reconstruction surgery at our tertiary care children's hospital from June 2008 through February 2012 were reviewed. Operative reports were reviewed for any indication that an anomaly existed in the pes anserinus or that there was difficulty harvesting the required tendons. Magnetic resonance imaging (MRI) studies were then reviewed for these patients looking for evidence of any anomaly within the pes anserinus structures. Retrospective review was performed on 123 children (mean age, 16.1 years). Three girls (mean age, 16.2 years) were identified as having a low-lying muscle belly and accessory tendon when attempting to harvest the gracilis tendon. Proximal exploration of this short tendon conjoining the gracilis insertion revealed a muscle belly approximately 5 cm from its insertion in the pes anserinus. This anomaly was present in 2.4% of the cases. Based on previous literature, the anomalous muscle present in our cohort could be sartorius or semimembranosus. MRI analysis suggests that the accessory muscle and tendon could be an aberrant strip of the semimembranosus tendon, an anomalous tendon and muscle belly of the gracilis, or a thickening and separation of the sartorius tendon. Anomalous pes anserinus tendons were found to exist in 2.4% of our adolescent study population. At the time of surgery, if a tendon is harvested with a very low-lying muscle belly (with less than 6 cm of tendon), then the presence of an aberrant tendon should be considered. Preoperative MRI may provide evidence of an anomalous tendon if that information is sought.

Ultrasonographic assessment of pes anserinus tendon and pes anserinus tendinitis bursitis syndrome in patients with knee osteoarthritis

Objective. The aim of this study was to assess the ultrasonographic (US) findings of pes anserinus tendon and bursa in patients with knee osteoarthritis (OA) with or without clinical pes anserinus tendinitis bursitis syndrome (PATBS).Methods. A total of 157 female patients with the diagnosis of knee OA on both knees (314 knees), and 30 age, and body mass index- matched healthy female controls without knee pain (60 knees), were included in the study. PATBS was clinically diagnosed. US evaluation parameters were the measurement of the thickness of pes anserinus tendon insertion region (PA) and examination of the morphologic intratendinous PA tissue characteristics and pes anserinus bursitis (PAB). Radiographic knee osteoarthritis graded I-IV according to Kellgren and Lawrence (KL) for each knee was recorded. Pain and functional status were assessed by the Visual Analog Scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).Results. There were 183 PATBS (58.3%) clinical diagnoses among the 314 knees with OA. The mean thickness of PA in the patients with knee OA graded 1,2,3,4 with/without PATBS was significantly greater than the controls (p = 0.001). The mean thickness of PA in knees with OA KL graded 3 and 4 with/without PATBS, was greater than knees with OA KL graded 1 and 2 with/without PATBS (p < 0,05) (except knee OA KL graded 2 with PATBS versus knee OA KL graded 4 without PATBS).The knee OA KL graded 1,2,3,4 with PATBS had significantly more PAB and less loss of normal fibrillar echotexture of PA compared to controls and knees with OA KL graded 1,2,3,4 without PATBS (p < 0.05). The VAS scores of knees with OA KL graded 3, 4 with PATBS were significantly greater than those of knees with OA KL graded 3,4 without PATBS (p < 0.05). PA thickness was significantly associated with the KL grade (r: 0.336, p:0.001) and PATBS (r: 0.371, p < 0.001).Conclusion. It is concluded that the mean thickness of PA in knees with OA with/without PATBS was significantly greater than the controls. The mean thickness of PA in knees with OA, KL graded 3 and 4 with/without PATBS, was greater than in knees with OA KL graded 1 and 2 with/without PATBS. The knee OA with PATBS had significantly more PAB, less loss of normal fibrillar echotexture of PA, and higher VAS scores compared to the knees with OA without PATBS. US can serve as a useful diagnostic tool for detection of PATBS in knee OA.

Sonoanatomic Variation of Pes Anserine Bursa

BackgroundThe pes anserine bursa lies beneath the pes anserine tendon, which is the insertional tendon of the sartorius, gracilis, and semitendinosus muscles on the medial side of the tibia, but it can lie in different sites in the medial knee. Accurate diagnosis of the position of the bursa is critical for diagnostic and therapeutic goals. The aim of this study was to evaluate sonoanatomic variations of the pes anserine bursa in the medial knee.MethodsOne hundred seventy asymptomatic volunteers were enrolled in this study. Using ultrasound imaging (transverse approach, 7-13 MHz linear array probe) the sonoanatomic position of the pes anserine bursa and its relation to the pes anserine tendon were evaluated. Additionally, we evaluated the sonoanatomic variation of the saphenous nerve.ResultsThe position of the pes anserine bursa was between the medial collateral ligament and the pes anserine tendons in 21.2%/18.8% (males/females) of subjects; between the pes anserine tendons and the tibia in 67.1%/64.7% (m/f); and among the pes anserine tendons in 8.2%/12.9% (m/f). No significant differences in the position of the bursa existed between males and females. The saphenous nerve was found within the pes anserine tendons in 77.6%/74.1% (m/f) of subjects, but outside the pes anserine tendons in 18.8%/15.3% (m/f). Visibility of sonoanatomic structures was not related to either gender or BMI.ConclusionsUltrasound provides very accurate information about variations in the pes anserine bursa and the saphenous nerve. This suggests that our proposed ultrasound method can be a reliable guide to facilitate approaches to the medial knee for diagnostic and therapeutic objectives.

‘Snapping’ knee secondary to a large juxta-articular ganglion

Ganglion, usually found around the wrist, is a very common cystic tumor. Presentations typically range from painless masses around joints to irritation or discomfort due to direct pressure on surrounding soft tissues. To our knowledge, however, juxta-articular ganglion as a cause of snapping of the knee has not been described previously in the literature. A 50-year-old male presented with snapping of the right medial pes anserinus tendon. The condition had been present for over 2 years, but had recently increased in frequency. A sporting injury had been ruled out as a cause. A large cystic lesion, suggestive of a ganglion, was observed by radiology on the medial aspect of the distal femur. After surgical excision of the lump, the symptoms were resolved and the patient made a good recovery. A histology report confirmed the lesion to be a ganglion.

Microvascular Flaps and Collateral Ligament Reconstructions for Soft Tissue Sarcomas at the Knee Joint

We report the suitability of free flap reconstruction in defects around the knee joint caused by soft tissue sarcoma (STS) excisions. The importance of collateral ligament reconstruction is also evaluated.Between years 1993 and 2005, 15 STS patients having a STS at the knee area with the need for free flap were treated in Helsinki University Hospital. Eleven musculocutaneous latissimus dorsi, 3 fasciocutaneous anterolateral thigh flaps, and 1 osteomusculocutaneous latissimus dorsi were used. The reconstruction of collateral ligaments was performed for 7 patients, 4 medial and 3 lateral; 6 with bone-tendon-bone grafts from patellar tendon and 1 with pes anserinus tendon transposition.There was no postoperative mortality. One flap was lost. Five patients needed debridement for minor wound complications. The mean follow-up time was 64 months. There were no local recurrences. Distant metastasis developed after the operation in 5 patients. Of these, 2 patients with solitary soft tissue metastasis were operated, and they are disease free. At 5 years 79% were disease-free. One patient with medial collateral reconstruction had recurrent patellar displacement and needed further operations; another with lateral collateral ligament and posterior capsular excision, that was not reconstructed, had lateral instability of the knee and needed orthosis.Free flap for STS of the knee is a reliable method. Patients can be operated with wider marginals and prognosis is good. Ligament reconstruction can be performed simultaneously, if collateral ligaments are excised.

Case Reports: A Stener-like Lesion of the Medial Collateral Ligament of the Knee

When the superficial fibers of the medial collateral ligament of the knee are torn without tearing of the deep fibers, the anterior superficial fibers may displace over the pes anserinus tendons, so that healing back to the tibial insertion site may be jeopardized. As only the anterior superficial and not the posterior superficial or deep fibers are disrupted, the knee will not have increased valgus laxity in extension whereas there is not a firm end point in 30 degrees flexion. The clinical findings could be confused with those of a Grade 2 medial collateral ligament sprain that generally is not associated with displacement of the anterior fibers over the pes anserinus tendons. We describe the diagnostic findings confirmed with surgical exploration of two Stener-like disruptions of the medial collateral ligament of the knee.

Predicting range of motion after total knee arthroplasty. Clustering, log-linear regression, and regression tree analysis.

Range of motion is a crucial measure of the outcome of total knee arthroplasty. The purpose of this study was to determine which factors are predictive of the postoperative range of motion. We retrospectively studied 3066 patients (4727 knees) who had a primary total knee arthroplasty with the same type of implant at the same center between 1983 and 1998. Statistical clustering analysis paired with log-linear regression was used to determine groupings along continuous variables. Regression tree analysis was used to characterize the combinations of variables influencing the postoperative range of motion. The variables considered were preoperative and intraoperative flexion and extension, preoperative alignment, age, gender, and soft-tissue releases. Preoperative flexion was the strongest predictor of the postoperative flexion regardless of preoperative alignment. Other factors that were significantly related to reduced flexion were intraoperative flexion (p < 0.0001), gender (p < 0.0001), preoperative tibiofemoral alignment (p = 0.0005), age (p < 0.0001), and posterior capsular release (p < 0.0001). The removal of posterior osteophytes was related to the greatest increase in postoperative flexion in the group of patients with a varus tibiofemoral alignment preoperatively. The principal predictive factor of the postoperative range of motion was the preoperative range of motion. Removal of posterior osteophytes and release of the deep medial collateral ligament, the semimembranosus tendon, and the pes anserinus tendon in patients with large preoperative varus alignment and the attainment of a good intraoperative range of motion improved the likelihood that a good postoperative range of motion would be achieved.