PHYSICAL THERAPY INTERVENTION FOR MEDIAL PATELLOFEMORAL LIGAMENT RECONSTRUCTION AFTER REPEATED LATERAL PATELLAR SUBLUXATION/DISLOCATION
BACKGROUND:The incidence of patellar subluxation or dislocation has been documented up to 43/100,000 with females more prevalent then males. There are many contributing factors involving the hip, knee, and ankle that lead to patellar subluxation. A patellar position of lateral tilt with lateral glide may indicate weakness of the vastus medialis oblique (VMO) and adductors, increased tightness in the iliotibial band, and overpowering of the vastus lateralis. Patella alta can predispose an individual to lateral dislocation due to the patella placement outside of the femoral trochlear groove with a disadvantage of boney stability. Other factors that may cause the patella to laterally sublux or dislocate during a functional activity or sporting activity include a position of femoral external rotation, tibial internal rotation, and excessive contraction of the vastus lateralis. The medial patellofemoral ligament (MPFL) aids in the prevention of a lateral patellar subluxation or dislocation. In cases where there is recurrent subluxation/dislocation and Magnetic Resonance Imaging confirms a MPFL tear, a reconstruction may be the treatment of choice. PURPOSE/OBJECTIVE:The purpose of this case series is to describe the post-surgical physical therapy management of MPFL reconstructions, outcomes using the Modified Cincinnati Knee Outcome Measure (MCKOM) and to propose staged physical therapy interventions for this pathology in the form of a treatment progression. METHODS:Post-operative management data and outcomes were retrospectively collected using a detailed chart review methodology from seven subjects who underwent MPFL reconstruction. FINDINGS/RESULTS:The Modified Cincinnati Knee Outcome Measure (MCKOM) was analyzed for each participant in four sections that were most important to the return and maintenance of participation in sport. At follow-up the mean scores for the seven subjects in Section 3 (instability) was 19.3/20, Section 4 (overall activity level) was 17.3/20, Section 7 (running activity) was 4.5/5, and Section 8 (jumping and twisting) was 4.3/5. Overall all subjects scored over an 80 which indicated excellent results for return to activity/sport. CONCLUSIONS:In this case series, seven subjects after MPFL reconstruction returned to sport or functional activity following a physical therapy treatment progression including proprioceptive-focused, and dynamic rehabilitation, along with a home exercise program. Based on these positive results and a review of relevant literature regarding MPFL rehabilitation, a rehabilitation progression was presented. LEVEL OF EVIDENCE/METHODS:Level 4- Case Series.
Effect of elbow flexion on the proximity of the PIN during 2-incision distal biceps repair
The posterior interosseous nerve (PIN) is at risk for injury during surgical dissection for distal biceps repair, yet the optimal position of elbow flexion to avoid a PIN injury has never been established for the 2-incision approach. The purpose of this study was to determine the proximity of the PIN to the radial tuberosity during surgical dissection in different degrees of elbow flexion. Ten cadaveric specimens with an intact elbow and forearm were dissected in full pronation using a modified Boyd-Anderson approach. Half of the dissections were completed in 90Â° of flexion and the other half were completed in maximal flexion. To simulate the location of the PIN during a single-incision biceps repair, the distance of the PIN to the radial tuberosity was recorded in full extension and supination. Results from these measurements were assessed for differences using paired t tests, with differences deemed significant for P values less than .05. The PIN was not identified in any of the 2-incision surgical dissections. Based on these findings, the proximity of the PIN to the radial tuberosity is not significantly affected by the degree of elbow flexion in the muscle-splitting 2-incision approach. In addition, a safe zone exists for avoiding PIN injury in a single-incision technique for distal biceps repair because a drill bit exiting the radial tuberosity greater than 1 cm in a distal-radial direction would place the PIN at risk.
Single-row modified mason-allen versus double-row arthroscopic rotator cuff repair: a biomechanical and surface area comparison
PURPOSE/OBJECTIVE:The purpose of this study was to compare the time-zero biomechanical strength and the surface area of repair between a single-row modified Mason-Allen rotator cuff repair and a double-row arthroscopic repair. METHODS:Six matched pairs of sheep infraspinatus tendons were repaired by both techniques. Pressure-sensitive film was used to measure the surface area of repair for each configuration. Specimens were biomechanically tested with cyclic loading from 20 N to 30 N for 20 cycles and were loaded to failure at a rate of 1 mm/s. Failure was defined at 5 mm of gap formation. RESULTS:Double-row suture anchor fixation restored a mean surface area of 258.23 +/- 69.7 mm(2) versus 148.08 +/- 75.5 mm(2) for single-row fixation, a 74% increase (P = .025). Both repairs had statistically similar time-zero biomechanics. There was no statistical difference in peak-to-peak displacement or elongation during cyclic loading. Single-row fixation showed a higher mean load to failure (110.26 +/- 26.4 N) than double-row fixation (108.93 +/- 21.8 N). This was not statistically significant (P = .932). All specimens failed at the suture-tendon interface. CONCLUSIONS:Double-row suture anchor fixation restores a greater percentage of the anatomic footprint when compared with a single-row Mason-Allen technique. The time-zero biomechanical strength was not significantly different between the 2 study groups. This study suggests that the 2 factors are independent of each other. CLINICAL RELEVANCE/CONCLUSIONS:Surface area and biomechanical strength of fixation are 2 independent factors in the outcome of rotator cuff repair. Maximizing both factors may increase the likelihood of complete tendon-bone healing and ultimately improve clinical outcomes. For smaller tears, a single-row modified Mason-Allen suture technique may provide sufficient strength, but for large amenable tears, a double row can provide both strength and increased surface area for healing.
Biomechanical evaluation after five and ten millimeter anterior glenohumeral capsulorrhaphy using a novel shoulder model of increased laxity
Anterior instability of the shoulder is classically treated with a capsulolabral repair, but in cases of capsular redundancy, shortening or shifting of the capsule is added. This study compared glenohumeral translations in intact shoulders after rotational stretching of the capsule and after progressive increasing of anterior-inferior capsular shifts. Seven cadaveric shoulders were mounted on a custom biomechanical testing apparatus. Rotational range of motion and glenohumeral translations were measured. To create laxity, the shoulders were rotationally stretched an additional 30% from the intact rotational range of motion about the axis of the humerus in external and internal rotation. Anterior-inferior capsular shifts of 5 and 10 mm were performed. Rotational stretching of the shoulder capsule created anterior laxity. A 5 mm capsular shift was ineffective, but a 10 mm shift restored anterior and total anteroposterior translation to the intact condition.
A cadaveric model of the throwing shoulder: a possible etiology of superior labrum anterior-to-posterior lesions
BACKGROUND:It has been speculated that a shift of the throwing arc commonly develops in athletes who perform overhead activities, resulting in greater external rotation and decreased internal rotation caused by anterior capsular laxity and posterior capsular contracture, respectively. Osseous adaptation in the form of increased humeral and glenoid retroversion may provide a protective function in the asymptomatic athlete but cannot explain the pathological changes seen in the shoulder of the throwing athlete. Therefore, the objective of the present study was to examine the biomechanical effects of capsular changes in a cadaveric model. METHODS:Ten cadaveric shoulders were tested with a custom shoulder-testing device. Humeral rotational range of motion, the position of the humerus in maximum external rotation, and glenohumeral translations in the anterior, posterior, superior, and inferior directions were measured with the shoulder in 90 degrees of abduction. Translations were measured with the humerus secured in 90 degrees of external rotation. To simulate anterior laxity due to posterior capsular contracture, the capsule was nondestructively stretched 30% beyond maximum external rotation with the shoulder in 90 degrees of abduction. This was followed by the creation of a 10-mm posterior capsular contracture. Rotational, humeral shift, and translational tests were performed for the intact normal shoulder, after anterior capsular stretching, and after simulated posterior capsular contracture. RESULTS:Nondestructive capsular stretching resulted in a significant increase in external rotation (average increase, 18.2 degrees 2.1 degrees ; p < 0.001), and subsequent simulated posterior capsular contracture resulted in a significant decrease in internal rotation (average decrease, 8.8 degrees +/- 2.3 degrees ; p = 0.02). There also was a significant increase in anterior translation with the application of a 20-N anterior translational force after nondestructive capsular stretching (average increase, 1.7 +/- 0.3 mm, p = 0.0006). The humeral head translated posteroinferiorly when the humerus was rotated from neutral to maximum external rotation. This did not change significantly in association with anterior capsular stretching. Following simulated posterior capsular contracture, there was a trend toward a more posterosuperior position of the humeral head with the humerus in maximum external rotation in comparison with the position in the stretched conditions, although these differences were not significant. CONCLUSIONS:A posterior capsular contracture with decreased internal rotation does not allow the humerus to externally rotate into its normal posteroinferior position in the cocking phase of throwing. Instead, the humeral head is forced posterosuperiorly, which may explain the etiology of Type-II superior labrum anterior-to-posterior lesions in overhead athletes.
Revision anterior cruciate ligament reconstruction: three- to nine-year follow-up
PURPOSE/OBJECTIVE:With the increasing number of primary anterior cruciate ligament (ACL) reconstructions, revisions are more frequent. The literature quotes inferior results for revision cases when compared with primary ACL reconstruction. The purpose of the study was to review our institution's experience with revision ACL reconstruction. TYPE OF STUDY/METHODS:Retrospective case series. METHODS:Thirty-five revision cases were performed between 1993 and 1999. Twenty-nine were available for follow-up. Subjective scores were calculated for Lysholm, Tegner, and International Knee Documentation Committee (IKDC) forms. Objective IKDC scores were determined. KT-1000 measurements were performed as well as isokinetic strength testing of quadriceps and hamstrings. Plain film radiographs were obtained to assess degenerative changes. RESULTS:The average patient age at time of revision was 30.2 years, the average time to revision was 56 months, the follow-up from last revision was 67 months. Twenty-two patients had bone-patellar tendon-bone (BPTB) allograft, 6 had contralateral BPTB autograft, and 1 patient had Achilles allograft. Overall, KT-1000 measurement showed an average of 2.78 mm side-to-side difference of displacement. The allograft versus the autograft group was 3.21 mm versus 1.33 mm, respectively. Prerevision data were unavailable. However, all patients had a positive pivot-shift test before revision. Average postrevision Lysholm, Tegner, and subjective IKDC scores were 86.6, 11.86, and 85.86, respectively. Concerning the IKDC objective scores, 15 patients had an A score, 8 had a B score, and 4 had a C score. All 29 patients available for follow-up reported that they would have the surgery again. The average strength of quadriceps and hamstrings ranged from 82% to 88% of uninvolved side. CONCLUSIONS:This study provides long-term follow-up with good results for revision ACL reconstruction. Attention to principles when performing revision ACL surgery is critical to provide satisfactory results. LEVEL OF EVIDENCE/METHODS:Level IV.
Inferior vena cava filters prevent pulmonary emboli in patients with metastatic pathologic fractures of the lower extremity
The records of 47 consecutive patients with metastatic pathologic fractures of the lower extremity were analyzed with respect to thromboembolic complications. All patients were unable to receive pharmacologic deep venous thrombosis prophylaxis, and were stratified into two groups, based on use of an inferior vena cava filter. Group I (n = 24) consisted of patients who had an inferior vena cava filter plus mechanical deep venous thrombosis prophylaxis (compression stockings and sequential compression boots); Group II (n = 23) consisted of a group of patients receiving only mechanical deep venous thrombosis prophylaxis. All patients had routine lower extremity venous duplex imaging preoperatively, postoperatively, and before hospital discharge. At final followup, patients were examined for deep venous thrombosis and reviewed for thromboembolic events. At a mean followup of 11.5 months, Group I had two detectable deep venous thromboses and no pulmonary emboli; Group II had one detectable deep venous thrombosis and five pulmonary embolisms. In Group II, 40% (two of five) of pulmonary embolisms were fatal, yielding an 8.7% (two of 23) group mortality rate. Overall, the entire group had an approximately 17% deep venous thrombosis rate. Only 6.4% (three of 47) of deep venous thromboses were detectable by standard duplex imaging. The majority of deep venous thromboses (five of eight, 62.5%) were nondetectable by duplex imaging. Overall, a 4.3% (two of 47) death rate was attributable to pulmonary embolism. In contrast, an 8.6% (four of 47) mortality rate occurred in Group II alone. All pulmonary embolisms occurred in patients who did not receive an inferior vena cava filter. The majority of venous thromboses (62.5%) were not detectable on duplex scanning, therefore were thought to arise from the pelvic venous system. Complications related to inferior vena cava filter insertion were minimal. For patients with metastatic pathologic fractures of the lower extremities who are unable to receive pharmacologic deep venous thrombosis prophylaxis, the use of inferior vena cava filters, in conjunction with standard mechanical deep venous thrombosis prophylaxis, is a procedure that has a low risk and is useful adjunct to prevent fatal pulmonary embolisms.
The mechanical effects of suture anchor insertion angle for rotator cuff repair
Twelve matched pairs of humerii were instrumented with suture anchor at 90 degrees, 75 degrees, 45 degrees, and 30 degrees relative to the cortical border at the junction of the greater tuberosity and articular surface. Two fixtures were inserted into each specimen at different angles and loaded to failure. Suture anchors failed at an average of 171, 219, 169, and 192 N with 90 degrees, 75 degrees, 45 degrees, and 30 degrees insertion angles, respectively. No statistical difference was detected between groups (P=.08). Although previous authors have prescribed angles < or =45 degrees to improve pull-out strength, the current in vitro data does not support these recommendations