Beth E. Shubin Stein

The Docking Technique for Medial Patellofemoral Ligament Reconstruction: Surgical Technique and Clinical Outcome

Background Current techniques of medial patellofemoral ligament (MPFL) reconstruction vary with respect to methods of fixation on the femur and the patella. This article presents the outcomes of a surgical technique for reconstruction of the MPFL that uses a soft tissue graft with interference screw fixation on the femur and a docking technique for fixation on the patella. Hypothesis Patients with patellar instability who are treated with the docking technique for MPFL reconstruction will have improvements in knee symptoms and function, with a high percentage achieving good to excellent results at early follow-up. Study Design Case series; Level of evidence, 4. Methods Twenty consecutive patients with patellar instability underwent reconstruction of the MPFL. Patients were evaluated preoperatively and postoperatively by physical and radiographic examination and subjectively with the IKDC (International Knee Documentation Committee), Tegner, Kujala, and Lysholm questionnaires. Nineteen patients underwent magnetic resonance imaging preoperatively. Results The average follow-up was 31 months (range, 24–39). No recurrent episodes of dislocation or subluxation were reported. A firm endpoint to lateral patellar translation was noted in all patients at most recent follow-up. The IKDC subjective knee evaluation score improved from 42 preoperatively to 82 postoperatively (P < .001); Kujala, from 50 to 88 (P < .001); Lysholm, from 50 to 89 (P < .001); and Tegner, from 3.6 to 5.6 (P < .001). Conclusion The docking technique for MPFL reconstruction is an effective surgical procedure for the treatment of patellar instability.

The effect of muscle paralysis using Botox on the healing of tendon to bone in a rat model.

HYPOTHESIS Despite good clinical results after rotator cuff repair, follow-up studies show significant rates of failed healing. This may be because of excessive tension on the repaired tendon due to shoulder motion. We hypothesized that botulinum toxin A injections would result in improved attachment strength and collagen organization at the tendon-bone interface at early time points but may result in decreased mechanical properties at later time points because of the negative effects of stress deprivation. MATERIALS AND METHODS We performed division and repair of the supraspinatus tendon in 132 rats: 66 underwent repair alone and 66 received injections of botulinum toxin into the muscle before repair. Rats were killed at 4, 8, and 24 weeks and were evaluated by use of histologic, biomechanical, and micro-computed tomography analyses. RESULTS At 4 and 24 weeks, there was no significant difference in load to failure between groups. At 8 weeks, the botulinum group had a significantly lower load to failure compared with controls (27.7 N vs 46.7 N, P < .01). The weight of the supraspinatus muscle was significantly decreased at 4 and 8 weeks in the botulinum group, but it recovered by 24 weeks. Micro-computed tomography analysis showed the botulinum group to have significantly less bone volume, total mineral content, and total mineral density at 8 weeks. Histologic analysis showed formation of a more normal tidemark and increased collagen fiber organization in the botulinum specimens at 4 weeks. DISCUSSION Botulinum toxin A-treated specimens had increased collagen fiber organization at 4 weeks and decreased mechanical properties at later time points. The rapid healing of the rat rotator cuff likely makes it difficult to realize benefits from reduction in strain.

The Moving Patellar Apprehension Test for Lateral Patellar Instability

Background Physical examination maneuvers for patellar instability are often inaccurate. Hypothesis The “moving patellar apprehension test” is a sensitive and specific physical examination technique for the diagnosis of patellar instability. Study Design Cohort study (diagnosis); Level of evidence, 3. Methods The moving patellar apprehension test was performed in an office setting preoperatively and compared with the ability to dislocate the patella when examined under anesthesia in 51 patients. The examination begins with the knee held in full extension and the patella is manually translated laterally with the thumb. The knee is then flexed to 90° and then brought back to full extension while the lateral force on the patella is maintained. For the second half of the test, the knee is started in full extension, brought to 90° of flexion, and then back to full extension while the index finger is used to translate the patella medially. For a positive test in part 1, the patient orally expresses apprehension and may activate his or her quadriceps in response to apprehension. In part 2, the patient experiences no apprehension and allows free flexion and extension of the knee. Results When compared with the ability to dislocate the patella under anesthesia, the moving patellar apprehension test was found to have a sensitivity of 100%, a specificity of 88.4%, a positive predictive value of 89.2%, a negative predictive value of 100%, and an accuracy of 94.1%. Conclusion The moving patellar apprehension test is an accurate physical examination technique that, when performed and interpreted correctly, is highly sensitive and specific for patellar instability.

Is there an association between chronicity of patellar instability and patellofemoral cartilage lesions? An arthroscopic assessment of chondral injury.

The purpose of this study was to investigate the association between chronicity of patellar instability on the prevalence, grade, and location of chondral lesions in patients with recurrent patellar instability. Patellofemoral chondral status was documented and graded according to the Outerbridge classification in 38 patients who underwent arthroscopic examination at the time of a medial patellofemoral ligament reconstruction procedure. Chondral lesions of any location were observed in 63.2% of patients. Patellar and trochlear lesions were observed in 57.9 and 13.2% of patients, respectively. There was a significantly higher duration of patellar instability in patients with a trochlear lesion versus those without a trochlear lesion (p < 0.01), and in patients with combined patellar and trochlear lesions versus those without both patellar and trochlear lesions (p < 0.01). There was a significant correlation between chronicity of patellar instability and Outerbridge grade of trochlear chondral injury (p = 0.01). Chi-squared analysis revealed that chronicity of patellar instability greater than 5 years was significantly associated with the likelihood of trochlear lesions (p < 0.05). We conclude that patients with increasing chronicity of patellar instability may have a higher likelihood of and higher grade of patellofemoral chondral injuries, specifically for trochlear lesions.

Repair of Chronic Pectoralis Major Ruptures

Traumatic ruptures of the pectoralis major tendon were once thought to be an extremely rare injury. Over the last 20 years the number of reported cases has risen significantly. Weightlifting is by far the most common sport associated with pectoralis major ruptures. In the past, these injuries were generally treated non-operatively. However, most authors now agree that surgical repair of pectoralis major tendon tears is the treatment of choice in order to regain full strength in the young, active patient. Although most surgeons prefer to repair the ruptured tendon in the acute setting, outcomes of surgical repair of chronic ruptures have shown excellent results with regard to appearance, function and strength.

Patellar Instability Management: A Survey of the International Patellofemoral Study Group:

Background: Although patellofemoral instability is among the most prevalent knee disorders, the management of patients with this condition is complex and remains variable, given the lack of long-term, high-level clinical outcome studies to compare various operative and nonoperative modalities. Purpose: To discover a consensus within treatment controversies in patellofemoral instability among experienced knee surgeons with a specific interest in the patellofemoral joint. Study Design: Expert opinion; Level of evidence, 5. Methods: A 3-step modified Delphi technique was used to establish a consensus. A 34-question, case-based online survey regarding patellofemoral instability was distributed to all active members of the International Patellofemoral Study Group. Consensus statements were generated if at least 66% of the respondents agreed and then redistributed to the same panel. Modifications to the consensus statements were made based on the iterative feedback process until no discordance was encountered in the third stage. Results: Eight consensus statements were achieved. Nonoperative management is the current standard of care for a first-time dislocation in the absence of an osteochondral fragment or loose body requiring excision (100% agreement). In patients with a first-time dislocation with an operative osteochondral fracture requiring excision or repair, patellar instability should be addressed concurrently (89% agreement). Recurrent instability should be treated surgically, with most surgeons favoring medial reconstruction (77%-86% agreement). While there is general agreement that bony procedures should be performed to correct underlying bony deformities, there is no consensus regarding the most appropriate type of procedure performed. Lateral release should not be performed in isolation for the treatment of patellar instability (89% agreement). Conclusion: Despite the consensus generated in this study, our current understanding remains limited by a lack of high-level evidence as well as the numerous complex variables influencing treatment decision making. High-quality, multicenter randomized controlled trials, particularly those directly comparing specific surgical treatment methods while controlling for underlying risk factors, are needed to address these areas of uncertainty.

Anisometry of Medial Patellofemoral Ligament Reconstruction in the Setting of Patella Alta and Increased Tibial Tubercle-Trochlear Groove (TT-TG) Distance

Objectives: Medial patellofemoral ligament (MPFL) reconstruction is a common procedure to treat recurrent patellofemoral instability. However, the effects of an elevated tibial tubercle-trochlear groove (TT-TG) distance and patella alta, as measured by the Caton-Deschamps (C/D) ratio, on MPFL isometry remain unclear. We hypothesized that increased lateralization and proximalization of the tibial tubercle (TT) will have increasingly adverse effects on the isometry of the MPFL. Methods: Ten fresh-frozen cadaveric knees were placed on a custom testing fixture, with a fixed femur and tibia mobile through 120 degrees of flexion. The quadriceps tendon was loaded with 10.8 N in an anatomic direction using a weighted pulley system. A 0.2 N patellar lateral displacement load was used to simulate an intact lateral retinaculum to avoid over-medializing the patella. A tunnel was drilled under fluoroscopic guidance from Schottle’s point on the medial distal femur through the lateral cortex. A suture anchor was placed at the upper 66% of the medial border of the patella and the sutures were shuttled through to the lateral side and attached to a pulley with a 1 N weight. Retroreflective markers were attached to the femur, tibia, patella, and suture. MPFL length change, as measured by suture marker motion, was assessed using a 3D motion capture system through a range of motion between 0 deg and 110 deg with the native TT anatomy. Recordings were repeated after a flat TT osteotomy and transfer to a TT-TG of 20 mm and 25 mm and a C/D ratio of 1.2 and 1.4, including all combinations. Generalized estimating equation (GEE) modeling technique was used to analyze and control for the clustered nature of the data. SAS version 9.3 (SAS Inc., Cary, NC) was used for all data analyses. Results: Analysis was performed on 9 specimens secondary to significant deviations in the baseline normative data. Intact knees showed MPFL isometry through 20-70 degrees range of motion. Tibial tubercle lateralization significantly altered MPFL isometry with a threshold TT-TG of 25 mm (p=0.045) (Figure 1). Patella alta significantly altered MPFL isometry with a threshold C/D of 1.4 (p=0.025) (Figure 2). The effect of TT lateralization combined with patella alta compounded the anisometry, lowering the threshold for patella alta to a C/D of 1.2 when combined with a TT-TG of 25 mm (P<0.001) (Figure 3). Conclusion: Increased TT lateralization and proximalization significantly alter MPFL isometry. Tibial tubercle transfer should be considered when performing an MPFL reconstruction for recurrent patellofemoral instability in the setting of significant patella alta, elevated TT-TG and especially when both are present as an isolated MPFL reconstruction may be prone to failure given the anisometry demonstrated.

Incidence of Deep Venous Thrombosis After Tibial Tubercle Osteotomy A Single Case Series Study

Background: Tibial tubercle osteotomy (TTO) is performed in a predominantly young and often female population due to the prevalence of patellofemoral disorders in this group. While considered a procedure that falls within the realm of sports surgeries, the procedure can carry significant morbidity, including infection, fracture, and deep vein thrombosis (DVT). The incidence of postoperative DVT in this population has not been described in the literature, although it has been mentioned anecdotally, and current guidelines do not address the issue of DVT prophylaxis in postoperative TTO patients. Purpose: To describe the incidence of DVT after TTO and identify any predisposing factors. Study Design: Case series; Level of evidence, 4. Methods: Subjects who had undergone TTO by the senior author from 2002 to 2013 were identified, and a retrospective chart review was performed. Those who presented with symptomatic DVT confirmed with ultrasonography were reported. Demographic data, as well as potential risk factors such as body mass index, family history of bleeding/clotting disorders, duration of the nonweightbearing period, total tourniquet time, use of contraceptive medication, smoking status, and use of anticoagulants, were collected from the chart and analyzed for correlation with development of DVT. Results: A total of 156 patients were included in this study. Six patients were found to have developed symptomatic DVT during the first 6 weeks after surgery. The mean age at the time of surgery in the DVT group was 34.94 ± 6.57 years, compared with 26.26 ± 10.20 years in the non-DVT group (P = .04). Due to the small number of patients with positive findings, there was no statistically significant correlation between the development of DVT and factors such as nonweightbearing duration, tourniquet time, or the use of contraceptives. Conclusion: The incidence of postoperative DVT in arthroscopic and sports procedures has been thought to be low. This case series reported a rate of 3.8% with symptomatic DVT after TTO, and patients diagnosed with DVT were significantly older than unaffected patients. It is anticipated that the actual rate including asymptomatic DVT would be higher, as only 60% of patients with DVT are symptomatic. More studies are needed to define the actual incidence in this population. Given the number of common risk factors in this population, including nonweightbearing duration and the use of oral contraceptive pills, future studies may show the advantage of chemical prophylaxis for DVT in this group.

Surgical treatment of a chronically fixed lateral patella dislocation in an adolescent patient

Acute patellar dislocation or subluxation is a common cause for knee injuries in the United States and accounts for 2% to 3% of all injuries. Up to 49% of patients will have recurrent subluxations or dislocations. Importance of both soft tissue (predominantly, the medial patellofemoral ligament, MPFL, which is responsible for 60% of the resistance to lateral dislocation) and bony constraint of femoral trochlea in preventing subluxation and dislocation is well documented. Acute patella dislocation will require closed reduction and management typically consist of conservative or surgical treatment depending on the symptoms and recurrence of instability. Most patients are diagnosed and treated in a timely manner. We present a 15 years old male with a missed traumatic lateral patella dislocation during childhood. The patient presented as an adolescent with a chronically fixed lateral patella dislocation and was management with surgery. The key steps in the surgical reconstruction of this patient required first mobilizing the patella with a lateral retinacular release and V-Y lengthening of the shortened or contracted quadriceps tendon. Then a combination of MPFL reconstruction using the semitendinosis autograft, tibial tubercle osteotomy with anterio-medialization, and lateral facetectomy was performed. At the one-year follow-up, our patient had improved knee range of motion and decrease in pain. Chronically fixed lateral dislocated patella is a rare and complex problem to manage in older patients that will require a thorough work-up and appropriate surgical planning along with reconstruction.

Arthritis and osteotomies in anterior cruciate ligament reconstruction

Unfortunately, young patients with active life-styles who present with an ACL-deficient knee and early evidence of arthritis remain a very difficult population to treat. Arthroscopic ACL reconstruction is a proven and effective way to treat patients with anterior knee instability [2]. In addition, numerous authors have demonstrated that knee osteotomies are effective in addressing isolated medial or lateral compartment degenerative disease, even in the presence of anterior knee instability [7, 9, 22, 43]. A comprehensive evaluation of pain, alignment, and stability are necessary in order to formulate the best treatment plan for each patient. Patients with combined chronic instability secondary to ACL insufficiency and unicompartmental arthritis will generally benefit from arthroscopic debridement, ACL reconstruction, knee osteotomy, or any combination thereof. Expectations of patients should be managed according to their underlying pathology, and this is a critical component for the success of the surgery. Most patients will get some degree of symptomatic relief and functional improvement. A return to competitive or high-level sports is an unrealistic goal, however, and should be discouraged.