Lonnie E. Paulos

Infrapatellar contracture syndrome. An unrecognized cause of knee stiffness with patella entrapment and patella infera.

Infrapatellar Contracture Syndrome (IPCS) is an infre quently recognized cause of posttraumatic knee mor bidity. Unique to this group of patients is the combina tion of restricted knee extension and flexion associated with patella entrapment. IPCS can occur primarily as an exaggerated pathologic fibrous hyperplasia of the anterior soft tissues of the knee beyond that associated with normal healing. It can also occur secondarily to prolonged immobility and lack of extension associated with knee surgery, particularly intraarticular ACL recon struction. IPCS follows a predictable natural history which is divided into three stages. Symptoms, diagnos tic findings, and recommended treatment are deter mined by the stage at presentation. Once beyond its early presentation, IPCS is best treated by an anterior intraarticular and extraarticular capsular debridement and release, followed by extensive rehabilitation. The authors review 28 consecutive cases of IPCS. At fol lowup 3 months to 4 years postoperation, the patients had averaged 2.3 additional surgical procedures follow ing their index procedure or injury. The average increase in extension at followup was 12° with the average increase flexion 35°. Eighty per cent of patients demonstrated signs and symptoms consistent with patellofemoral arthrosis; 16% of the patients demonstrated patella infera. The authors con clude that prevention or early detection and aggressive treatment are the only ways of avoiding complication in these problem cases.

Lateral release of the patella: Indications and contraindications:

Charts were reviewed on patients at the Salt Lake Knee and Sports Medicine Clinic who had had a lateral release of the patella. Patients were divided into two groups. Group I contained patients who were entirely satisfied with the procedure, and Group II included patients who were complete failures (defined as a need for further surgical procedures). In Group I, 74 patients were included in the subjective followup. Forty of the 74 patients also had an objective followup, including roentgenograms and a physical examination. Group II contained 43 patients. Results indicated that the most predictable criterion for success was a negative passive patellar tilt. Secondary criteria included a medial and lateral patellar glide of two quadrants or less and a normal tubercle-sulcus angle at 90° of flexion. Patients had less predictable results after an isolated lateral release with a positive (greater than 5°) passive patellar tilt and a three quadrant or greater medial and lateral patellar glide or an abnormal tubercle-sulcus angle at 90° of flexion.

Infrapatellar Contracture Syndrome Diagnosis, Treatment, and Long-Term Followup

Infrapatellar contracture syndrome is an uncommon but recalcitrant cause of reduced range of motion after knee surgery or injury. The results and conclusions pre sented here are based on a retrospective clinical study evaluating the long-term outcome in 75 patients who developed infrapatellar contracture syndrome. These 75 patients (76 knees) were evaluated at an average followup of 53 months after the index (inciting) proce dure or injury. Comparing subgroups within the study population, factors that correlated with poorer results or more severe infrapatellar contracture syndrome were found to be acute anterior cruciate ligament repair or reconstruction, the use of patellar tendon autograft for anterior cruciate ligament reconstruction, nonisometric graft placement, multiple surgical procedures, use of closed manipulation, and the development of patella infera. We concluded that appropriate procedures can substantially increase the range of motion in patients with infrapatellar contracture syndrome. However, re sidual functional morbidity persists in many patients, and the outcome, as determined by subjective knee function scores, is only fair. The natural history of an anterior cruciate ligament-deficient knee appears to be more benign than the natural history of a knee that de velops infrapatellar contracture syndrome.

Why grafts fail.

Significant advances in anterior cruciate ligament reconstructive surgery have been made in the past decade and, as a result, the number of anterior cruciate ligament reconstructive procedures being done have increased. Unfortunately, graft failure continues to occur and has resulted in an emphasis on revision surgery. Successful anterior cruciate ligament reconstruction is dependent on a number of factors including: patient selection, surgical technique, postoperative rehabilitation, and associated secondary restraint ligamentous instability. A particular emphasis both in scientific and clinical research has been placed on surgical technique. Errors in graft selection, tunnel placement, tensioning, or fixation methods chosen may lead to graft failure. Improper postoperative rehabilitation may lead to graft failure; however, current protocols seem to minimize its occurrence. Finally, failure to recognize or treat a significant secondary restraint instability can place excessive stress on the anterior cruciate ligament graft which may lead to failure. Care must be taken at every step of the process to ensure graft failure does not occur, because revision anterior cruciate ligament surgery results are not as predictable as primary anterior cruciate ligament reconstruction.

Preliminary results of an absorbable interference screw

A randomized, prospective multicenter comparison was done of a bioabsorbable interference screw (Bioscrew; Linvatec Corp, Largo, FL) made from poly L-lactic acid and a metal interference screw produced by the same company. Assignment was randomized by sealed envelopes. A total of 110 patients underwent arthroscopic patellar tendon autografts. A minimum 12 months follow-up is available on 85 patients (mean 19 months, range 12 to 33) including 42 with Bioscrews and 43 with metal screws. There were 56 male and 29 female patients. The average age was 29 years (16 to 50 years). Tourniquet times and associated surgical findings were similar for the two groups. Postoperative Tegner and Lysholm scores were not statistically different between the two groups. KT tests at 1 year showed an average 20-lb laxity of 1.8 mm for the Bioscrew and 1.2 mm for the metal screw groups. The average 1-year KT maximum manual side-to-side difference was 1.6 mm for Bioscrews and 1.6 mm for metal screws. A pivot shift was absent in 83% of Bioscrews and 90% of metal screws at follow-up. Six of 85 Bioscrews inserted (7%) broke on insertion (all were 7-mm diameter screws at the femoral site). No additional fixation was required in four cases. In two, the broken screw was replaced. No lytic bone changes or tunnel widening were found with any Bioscrew. One metal screw had tibial tunnel widening. No statistical difference was found between the Bioscrew and the metal screw groups. Short-term data support the conclusion that the Bioscrew is a reasonable alternative to metal interference screws.

Detailed Analysis of Patients with Bilateral Anterior Cruciate Ligament Injuries

To better understand anatomic and other possible pre disposing factors for anterior cruciate ligament injuries, we retrospectively studied 31 patients with noncontact, bilateral injuries of this ligament. The 31 patients were carefully matched by age, sex, height, weight, and ac tivity level with 23 control subjects who had no history of knee injury. All 54 subjects underwent a full clinical knee examination, joint hypermobility tests, a hamstring tightness assessment, a computerized tomography scan analysis, and a plain view radiographic analysis, and were asked to provide a complete immediate-family history of knee ligament injury. In addition, the 31 pa tients in the experimental group underwent a KT-1000 arthrometer knee laxity examination and were also asked to provide an injury profile, including mechanism of injury, treatment received for each injury, and the time interval between injuries. Measurements obtained from the computerized tomography scan analysis demon strated a significantly wider lateral femoral condyle in the experimental group compared with the control group, indicating that certain anatomic factors may pre dispose people to anterior cruciate ligament injury. A significant difference was also found in the incidence rate of anterior cruciate ligament injury in the family his tory of the experimental group compared with the con trol group, indicating a possible congenital aspect of this injury.

The GORE-TEX anterior cruciate ligament prosthesis A long-term followup

The GORE-TEX anterior cruciate ligament prosthesis has been implanted in 268 patients at our institution since April of 1984. Follow-up for this study was avail able on 70% of these patients (188). Eighty-one percent (152) of these had the ligament for chronic injuries, 14% (26) for acute, and 5% (10) for subacute injuries. The patient population had an average age of 27.6 years (SD = 8.4) and a Tegner activity score of 6.05 (SD = 1.53). Prior procedures had been performed on 56% (105) of the patients. Concomitant procedures were performed in 73% (137) and included iliotibial band tenodesis, partial meniscectomy, posterior oblique lig ament advancement, or meniscal repair. Followup av eraged 48 months (range, 24 to 68). Evaluation included a questionnaire, physical examination, radiographs, KT- 1000 arthrometer testing, and an activity score. Results were graded as excellent, good, fair, and poor. Acceptable results (good and excellent) were obtained in 83 patients (44%). Fifty-eight patients (32%) were rated excellent and 25 (13%) were rated good. Unacceptable results (fair and poor) were obtained in 105 patients (56%). Twenty-five patients (13%) were rated fair and 80 (42%) were rated poor. Subjective improvement was indicated by 166 patients (88%). Activity levels postoperatively as rated by the Tegner Scale improved in 2 (1 %), remained the same in 167 (89%), and decreased in 19 patients (10%). Effusions occurred in 63 patients (34%) and caused an unac ceptable result in 22 (12%). Rupture occurred in 23 patients (12%). Loosening greater than 3 mm occurred in 64 patients (34%) and led to unacceptable results in 37 (20%). Infection occurred in 5 patients (2.7%). Ex cellent results had a statistically significantly higher age and lower activity score than the poor results (P = 0.045 and 0.012, respectively). The patients with pre vious intraarticular reconstructions had a 76% unac ceptable rating (16 of 21).

Is an anterior cruciate ligament reconstruction outcome age dependent

Treatment of a torn anterior cruciate ligament (ACL) in older patients must be considered in relation to healing delays, rehabilitation difficulties, stiffness, arthritis, and actual athletic demands. This study compares ACL reconstructions in patients 40-years old and older with those under 40-years old and contrasts these to published nonoperative data in the 40 and older patient. Patients undergoing ACL reconstruction between 1992 and 1994 were preoperatively and postoperatively assessed with Lysholm, Tegner, KT, radiographic, and clinical examinations. They were divided into two groups: those 40 years and older (group 1) and those 39 years and younger (group 2). Group 1 had 33 patients with an average age of 44 years (range, 40 to 52 years). Radiographic Fairbank changes were absent. Group 2 had 170 patients with an average age of 27 years (range, 16 to 39 years). Group 1 preoperative instability and intake data were not statistically different from those of group 2. Average follow-up was 21 months for both groups. Both groups showed significant improvement in all parameters at 12- and 24-month follow-up examinations. Lysholm scores, Tegner scores, average KT manual maximum side-to-side differences, Lachman tests, and pivot shift testing were not statistically different in either group. Using Lysholm criteria, in group 1, 89% had excellent/good results, and 11% fair/poor results. This was not statistically different from group 2, which showed 91% excellent/good results and 9% fair/poor results at 24-month follow-up examination. For this age group, nonoperative treatment reports indicate 57% excellent/good results and 43% fair/poor results. The outcomes between these groups are the same and fail to establish the age of 40 years as a barrier to successful ACL reconstruction.

The biomechanics of lateral knee bracing Part I: Response of the valgus restraints to loading

To better understand the role of preventive knee braces in injury prevention, a biomechanical study using fresh frozen cadaveric knees (N = 18) was conducted. Liga ment tensions and joint displacements were measured at static, nondestructive valgus forces as well as low- rate destructive forces. After quantifying and establish ing individual ligament contributions to valgus restrain ing function, knees were then braced with two different laterally applied preventive braces, the McDavid Knee Guard and the Omni Anderson Knee StabIer.The effects of lateral bracing were analyzed according to valgus force, joint line opening, and ligament tensions. Valgus applied forces, with or without braces, consis tently produced medial collateral ligament (MCL) disrup tions at ligament tensions surprisingly higher than the anterior cruciate ligament (ACL) and higher than or equal to the posterior cruciate ligament (PCL). Although large joint displacements were necessary for complete ligament failure, bundle disruption in the MCL, ACL, and PCL was noted at much smaller joint openings. In Part I of this study, no significant protection could be documented with the two preventive braces used. Also, four potentially adverse effects were noted: MCL pre load, center axis shift, premature joint line contact, and brace slippage.

The current state of functional knee bracing research A review of the literature

This paper reviews recent research on functional knee bracing. Research is categorized by subject, approach, or technique. The authors conclude that, while there is a good deal of excellent research available, there is little data to assist the clinician in selecting an orthosis for a specific application. The authors recommend that future investigations address the physiologic aspects of functional knee bracing and that brace manufacturers assume more responsibility in the validation of both existing and future brace designs.