Donald C. Fithian

Fate of the ACL-injured Patient A Prospective Outcome Study

We followed 292 patients who had sustained an acute traumatic hemarthrosis for a mean of 64 months. The KT-1000 arthrometer measurements within 90 days of injury revealed the injured knee was stable in 56 pa tients and unstable in 236. Forty-five unstable patients had an ACL reconstruction within 90 days of injury. Sur gical procedures performed >90 days after injury in cluded ligament reconstruction in 46 patients. Factors that correlated with patients who had late surgery for a meniscal tear or an ACL reconstruction (P < 0.05) were preinjury hours of sports participation, arthrometer mea surements, and patient age. Follow-up data are presented for the patients divided into four groups: I, early stable, no reconstruction; II, early unstable, no reconstruction; III, early recon struction; and IV, late reconstruction. No patient changed occupation because of the knee injury. Hours per year of sports participation and levels of sports par ticipation decreased in all groups. Joint arthrosis was documented by radiograph and bone scan. Joint sur face injury abnormalities observed at surgery and me niscal surgery showed greater abnormalities by radio graph and bone scan scores ( P< 0.05). Reconstructed patients had a higher level of arthrosis by radiograph and bone scan.

Material properties and structure-function relationships in the menisci.

The menisci serve several important biomechanical functions in the knee. They distribute stresses over a broad area of articular cartilage, absorb shocks during dynamic loading, and probably assist in joint lubrication. These functions enhance the ability of articular cartilage to provide a smooth, near-frictionless articulation and to distribute loads evenly to the underlying bone of the femur and tibia. In addition, the menisci provide stability to the injured knee when the cruciate ligaments or other primary stabilizers are deficient. The ability to perform these mechanical functions is based on the intrinsic material properties of the menisci as well as their gross anatomic structure and attachments. The material properties of the menisci are determined by their biochemical composition and, perhaps more important, by the organization and interactions of the major tissue constituents: water, proteoglycan, and collagen. Interactions among the important constituents of the fibrocartilage matrix cause meniscal tissue to behave as a fiber-reinforced, porous, permeable composite material similar to articular cartilage, in which frictional drag caused by fluid flow governs its response to dynamic loading. The menisci are one-half as stiff in compression and dissipate more energy under dynamic loading than articular cartilage. Energy dissipation, or shock absorption, by the menisci is the result of high frictional drag caused by low permeability of the matrix, which is about one-sixth as permeable as articular cartilage. The dynamic shear modulus of meniscal tissue is only one-fourth to one-sixth as great as that of articular cartilage. The coarse, circumferential Type I collagen fiber bundles of the meniscus give the tissue great tensile stiffness (range, 100-300 megapascals) and strength. The highly oriented collagen ultrastructure of the menisci makes the tissue anisotropic in tension, compression, and shear and appears to dominate its behavior under all loading conditions.

Epidemiology and Natural History of Acute Patellar Dislocation

Background The goals of this study were to (1) define the epidemiology of acute patellar dislocation, (2) determine the risk of subsequent patellar instability episodes (subluxation and/or redislocation) during the study period, and (3) identify risk factors for subsequent instability episodes. Study Design Prospective cohort study. Methods The authors prospectively followed 189 patients for a period of 2 to 5 years. Historical data, injury mechanisms, and physical and radiographic measurements were recorded to identify potential risk factors for poor outcomes. Results Risk was highest among females 10 to 17 years old. Patients presenting with a prior history of instability were more likely to be female (P < .05) and were older than first-time dislocation patients (P < .05). Fewer first-time dislocators (17%) had episodes of instability during follow-up than patients with a previous history of instability (49%) (P < .01). After adjusting for demographics, patients with a prior history had 7 times higher odds of subsequent instability episodes during follow-up than first time dislocators (adjusted odds ratio = 6.6, P < .001). Conclusions Patellar dislocators who present with a history of patellofemoral instability are more likely to be female, are older, and have greater risk of subsequent patellar instability episodes than first-time patellar dislocators. Risk of recurrent patellar instability episodes in either knee is much higher in this group than in first-time dislocators.

Medial soft tissue restraints in lateral patellar instability and repair.

This study was undertaken to evaluate the medial ligamentous stabilizers of the patella in restraining lateral displacement and to assess their relative contribution after individual repair. Seventeen fresh frozen human anatomic specimen knee joints were studied. The specimens were loaded onto a testing instrument that was designed to measure the compliance of the medial and lateral patellar restraints in the coronal plane. Two different cutting and repair sequences were used to test the individual contributions of the patellar ligaments. The medial patellofemoral ligament was found to be the major medial ligamentous stabilizer of the patella. Isolated release resulted in a 50% increase in lateral displacement, and isolated repair restored balance to the patella. In addition, the patellotibial and patellomeniscal ligament complex played an important secondary role in restraining lateral patellar displacement. Isolated repair of these ligaments restored balance to near normal levels. The medial patellofemoral retinaculum played only a minor role in patellofemoral instability. Proximal realignment or medial ligament repair for patellofemoral instability specifically should address repair of the deep layers that contain the restraints to lateral patellar displacement. Failure to include these structures in repair, especially of the medial patellofemoral ligament, may lead to persistent or recurrent instability.

Current concepts of lateral patella dislocation

Surgical treatment of patellar dislocations, acute and chronic, has evolved significantly over the past decade with the advance of biomechanical knowledge of patellofemoral restraints and injury patterns identified by physical examination and improved imaging techniques. There continues to be no consensus on treatment parameters. Despite the presence of predisposing factors, such as dysplasia or generalized hyperlaxity, medial retinacular injury associated with primary (first-time) patellar dislocations represents a ligament injury, which may result in residual laxity of the injured structure. This residual laxity is defined objectively by an increase in passive lateral excursion of the patella. Repair or reconstructive procedures to restore this medial constraint is considered paramount in any procedure to stabilize the patella against subsequent dislocations. How best to accomplish this continues to be a matter of debate. The establishment of a medial check-rein by either repairing or reconstructing the MPFL is the procedure of choice for stabilizing a kneecap after first-time dislocation, largely because the literature to date does not provide clear guidelines about when more extensive surgery is indicated. Whether or not all first-time dislocators have improved outcome after surgical repair remains speculative, however. Improved outcome would involve both the elimination of recurrent instability episodes and continued satisfactory function of this patella in activities-of-daily-living and sporting activities. These outcomes have not been studied critically in operative versus nonoperative treatment of first-time patellar dislocation. For the first-time dislocator, most investigators would agree that an arthroscopy should be performed if intra-articular chondral damage is suspected. Nonoperative management of first-time patellar dislocations continues to be the preferred practice pattern in the United States. If surgical management is elected, because of individual characteristics of the injury pattern or the patients lifestyle, it is important to inspect the MPFL along its length and repair any or all ligamentous disruptions. If the ligament is avulsed from the medial epicondyle, reattachment to bone is necessary to restore passive restraint to lateral patella motion. MRI may be useful in order to identify the location and degree of medial soft tissue injury preoperatively. The establishment of a medial check-rein by either repairing or reconstructing the MPFL is a necessary component of all surgical procedures performed to correct objective lateral instability of the patella. The addition of a LRR should be additive to this procedure only when it facilitates other procedures to recenter the patella or when objective lateral tilt by physical examination measurements is present. A practical approach to surgery after patellar dislocation is the minimal amount of surgery necessary to re-establish objective constraints of the patella. Correcting dysplastic factors, in particular tibial tubercle transfers and trochleoplasties, are best reserved if more minimal surgery has failed. This failure is defined as continued functional instability of the kneecap.

Prospective Trial of a Treatment Algorithm for the Management of the Anterior Cruciate Ligament–Injured Knee

Background Specific guidelines for operative versus nonoperative management of anterior cruciate ligament injuries do not yet exist. Hypothesis Surgical risk factors can be used to indicate whether reconstruction or conservative management is best for an individual patient. Study Design Prospective nonrandomized controlled clinical trial; Level of evidence, 2. Methods Patients were classified as high, moderate, or low risk using preinjury sports participation and knee laxity measurements. Early anterior cruciate ligament reconstruction (within 3 months of injury) was recommended to high-risk patients and conservative care to low-risk patients. It was recommended that moderate-risk patients have either early reconstruction or conservative care, according to the day of presentation. Assessment of subjective outcomes, activity, physical measurements, and radiographs was performed at mean follow-up of 6.6 years. Results Early phase conservative management resulted in more late phase meniscus surgery than did early phase reconstruction at all risk levels (high risk, 25% vs 6.5%; moderate risk, 37% vs 7.7%, P =. 01; low risk, 16% vs 0%). Early- and late-reconstruction patients’ Tegner scores increased from presurgery to follow-up (P <. 001) but did not return to preinjury levels. Early-reconstruction patients had higher rates of degenerative change on radiographs than did nonreconstruction patients (P <. 05). Conclusions Early phase reconstruction reduced late phase knee laxity, risk of symptomatic instability, and the risk of late meniscus tear and surgery. Moderate- and high-risk patients had similar rates of late phase injury and surgery. Reconstruction did not prevent the appearance of late degenerative changes on radiographs. Relationship between bone contusion on initial magnetic resonance images and the finding of degenerative changes on follow-up radiographs were not detected. The treatment algorithm used in this study was effective in predicting risk of late phase knee surgery.

Characteristics of Patients With Primary Acute Lateral Patellar Dislocation and Their Recovery Within the First 6 Months of Injury

We prospectively studied the characteristics and early recovery of an unselected population of patients who had acute first-time lateral patellar dislocation. The recovery program used standardized rehabilitation, emphasizing range of motion, muscle strength, and return of function. Patients returned to stressful activities including sports as tolerated when they regained full passive range of motion, had no effusion, and when quadriceps muscle strength was at least 80% compared with the noninjured limb. Seventy-four patients met the enrollment criteria; 37 men and 37 women. The average age was 19.9 years, and preinjury sports participation was similar to that of ligament-injury patients. Four percent of patients (N 3) had a history of birth complications, 3% (N 2) had a history of lower extremity problems as an infant or child, and 9% (N 7) had a family history of patellar dislocation. Radiographs revealed a 50% incidence (N 37) of patella alta; all patients demonstrated lateral patellar overhang. Patients regained range of motion (mean, 0° to 132°) by 6 weeks. Sports participation remained significantly reduced throughout the first 6 months after injury, with the greatest limitations in kneeling and squatting. At 6 months, 58% of patients (N 43) noted limitation in strenuous activities. The patients who had acute primary patellar dislocation were young and active. Most injuries occurred during sports, and few patients had abnormal physical features, contradicting any stereotype of an overweight, sedentary, adolescent girl whose patella dislocates with little or no trauma.

An analysis of the risk of hip dislocation with a contemporary total joint registry.

Dislocation rates after total hip arthroplasty in a community setting have not been well documented. We used a community based joint registry to evaluate hip dislocations that occurred within 1 year after total hip arthroplasty. We evaluated patient, implant, and technical factors associated with dislocation, including primary versus revision surgery, femoral head size (28 mm versus ≥ 32 mm), operative time, surgeon volume, surgical approach, age, gender, diagnosis, American Society of Anesthesiologists (ASA) classification, and body mass index (BMI). There were 1693 primary total hip arthroplasties and 277 revision procedures performed from 2001-2003. The overall dislocation rate was 1.7% for primary total hip arthroplasties and 5.1% for revision procedures. Patients with ASA scores of 3 or 4 had a 2.3-fold dislocation increase compared with patients with scores of 1 or 2. Patients with rheumatoid arthritis had an increased risk of dislocation. The dislocation rates for primary total hip arthroplasty were 2% for 28 mm heads and 0.7% for heads ≥ 32 mm. The surgeons patient volume, surgical approach, operative time, and body mass index had no effect on dislocation.Level of Evidence: Prognostic study, level III. See Guidelines for Authors for a complete description of levels of evidence.

Fate of the anterior cruciate ligament-injured knee

Most patients with anterior cruciate ligament (ACL) injuries do well with activities of daily living even after follow-up in the range of 5 to 15 years. Most can participate in some sports activity if they are inclined to do so, but most will have some limitations in vigorous sports, and only a few will be entirely asymptomatic. The challenge to the clinician is to understand and predict how ACL deficiency in a given patient will affect that patientss life and activities. In counseling patients about treatment after an ACL injury, the clinician can use knee ligament arthrometry measurements and pre-injury sports activity to estimate the risk of injury over the next 5 to 10 years. Meniscus, chondral, and sub-chondral injuries are not uncommon, but rarely require surgical intervention in the early phase of ACL deficiency. The prevalence of clinically significant meniscal damage increases with time, and is associated with increasing disability, surgery, and arthrosis in high-risk patients. Ligament reconstruction has not been shown to prevent arthrosis, but in prospective studies it appears to reduce the risk of subsequent meniscal injury, improve passive anteroposterior knee motion limits, and facilitate return to high-level sporting activities.

Does Discharge Disposition After Primary Total Joint Arthroplasty Affect Readmission Rates

We reviewed 90-day readmission rates for 9150 patients with a primary total hip or knee arthroplasty performed between April 2001 and December 2004. Patients with an American Society of Anesthesiologists score of 3 or greater or with perioperative complications were excluded. We correlated the readmission rate with discharge disposition to either skilled nursing facilities (SNFs) or Home. Of the 9150 patients identified, 1447 were discharged to an SNF. After statistically adjusting for sex, age and American Society of Anesthesiologists scores, total hip arthroplasty and total knee arthroplasty patients discharged to SNFs had higher odds of hospital readmission within 90 days of surgery than those discharged home (total hip arthroplasty: odds ratio = 1.9; 95% confidence interval, 1.2-3.2; P = .008; total knee arthroplasty: odds ratio = 1.6; 95% confidence interval, 1.1-2.4; P = .01). Healthy patients discharged to SNFs after primary total joint arthroplasty need to be followed closely for complications.