Neuromuscular excitability changes in the vastus medialis following anterior cruciate ligament reconstruction.

PURPOSE: Quadriceps weakness following anterior cruciate ligament reconstruction (ACLR) is prevalent despite intensive rehabilitation. Diminished neuromuscular excitability is one potential factor that may limit muscular recovery following injury or surgery. The H-reflex provides a measure of alpha motorneuron (neuromuscular) excitability in the sensory-motor pathway of the respective muscle and nerve. To date the vastus medialis (VM) and soleus (SOL) H-reflexes have been examined primarily in control subjects with induced knee joint effusion. This prospective, randomized clinical trial evaluated the affect of ACLR, utilizing hamsting (HS) or bone-patellar tendon-bone (BTB) autograft, on VM and SOL H-reflex latency and amplitude in twenty subjects. METHODS: Preoperatively bilateral VM and SOL H-reflex tests were conducted. VM and SOL H-reflexes were subsequently conducted on the involved lower extremity at 1 and 3 months post surgery. At each test session subjects completed visual analog scales and knee girth was measured. RESULTS: The VM H-reflex amplitude increased in the HS group at 3 months compared to 1-month post surgery (p<.05). Significant changes over time were also noted in the visual analog pain and functional scales and the mid-patella girth. CONCLUSIONS: The increased VM H-reflex amplitude at 3 months following HS autograft ACLR demonstrates an increase in VM neuromuscular excitability. Increased VM neuromuscular excitability was not evident in patients following BTB reconstruction. The increased neuromuscular excitability, observed only in the HS group, warrants consideration when selecting graft type for patients with extensive preoperative quadriceps dysfunction.

Prospective evaluation of arthroscopic stabilization of acute, initial anterior shoulder dislocations in young athletes. Two- to five-year follow-up.

From March 1992 to November 1998, 57 patients sustained 58 acute, initial, traumatic anterior shoulder dislocations at the United States Military Academy. Six patients selected nonoperative treatment. Three patients underwent primary open repair after diagnostic arthroscopy revealed no Bankart lesion amenable to repair with the bioabsorbable tissue tack. The remaining 48 patients with 49 anterior dislocations were treated with arthroscopic primary repair. There were 45 men and 3 women with an average age of 20 years (range, 17 to 23) and an average follow-up of 37 months (range, 24 to 60). The average Rowe score was 92 (range, 30 to 100). The average single assessment numeric evaluation patient rating was 95.5% (range, 50% to 100%). The average Short Form-36 score (physical function) for the stable shoulders was 99 (range, 95 to 100). Forty-three shoulders remained stable (88%). There were six failures (12%). Factors associated with failure included a history of bilateral shoulder instability, a 2+ sulcus sign, and poor capsulolabral tissue at the time of repair. All patients with stable shoulders returned to their preinjury levels of athletic activity. With follow-up of 5 years, we have observed significantly better results compared with nonoperative treatment in young, active adults at the United States Military Academy.

Antimicrobial efficacy of external fixator pins coated with a lipid stabilized hydroxyapatite/chlorhexidine complex to prevent pin tract infection in a goat model.

BACKGROUND: Pin tract infection is a common complication of external fixation. An antiinfective external fixator pin might help to reduce the incidence of pin tract infection and improve pin fixation. METHODS: Stainless steel and titanium external fixator pins, with and without a lipid stabilized hydroxyapatite/chlorhexidine coating, were evaluated in a goat model. Two pins contaminated with an identifiable Staphylococcus aureus strain were inserted into each tibia of 12 goats. The pin sites were examined daily. On day 14, the animals were killed, and the pin tips cultured. Insertion and extraction torques were measured. RESULTS: Infection developed in 100% of uncoated pins, whereas coated pins demonstrated 4.2% infected, 12.5% colonized, and the remainder, 83.3%, had no growth (p < 0.01). Pin coating decreased the percent loss of fixation torque over uncoated pins (p = 0.04). CONCLUSION: These results demonstrate that the lipid stabilized hydroxyapatite/chlorhexidine coating was successful in decreasing infection and improving fixation of external fixator pins.

Pectoralis major muscle and tendon tears: diagnosis and grading using magnetic resonance imaging.

OBJECTIVE: To assess the accuracy and utility of magnetic resonance (MR) imaging in the detection and grading of pectoralis major muscle and tendon tears. DESIGN AND PATIENTS: A retrospective review was carried out of 10 patients referred for MR imaging for suspected pectoralis muscle injury and possible operative therapy. The pectoralis muscle and tendon were imaged using thin (3-4 mm) axial sections with a variety of sequences combined for anatomical delineation (T1-weighted SE or PD SE) and fluid detection (T2-weighted SE, T2-weighted FSE with fat suppression, or STIR). Surgical correlation was available in six patients. Clinical follow-up was available in four patients treated by nonoperative therapy. RESULTS: MR imaging identified five complete tears, four partial tears and one normal tendon. One complete and one partial tear were at the myotendinous junction. The remaining seven injuries were at the enthesis. Surgical correlation consisted of five complete tears and one partial tear. One complete and one partial tear were at the myotendinous junction with the remaining four complete tears at the enthesis. The MR interpretation and surgical findings were in agreement in all six cases. All four patients treated with nonoperative therapy demonstrated improvement at a clinical follow-up examination, with restoration of function and strength consistent with a healed prior partial injury. CONCLUSION: MR imaging is accurate and useful in detecting and grading tears involving the pectoralis major muscle and tendon, facilitating the identification of patients with complete tears who are candidates for operative therapy.

An intra-articular bioabsorbable interference screw mimicking an acute meniscal tear 8 months after an anterior cruciate ligament reconstruction.

SUMMARY: Seven months after a quadrupled semitendinosus anterior cruciate ligament reconstruction, a 44-year-old active-duty soldier reported symptoms consistent with a medial meniscus tear. Preoperative magnetic resonance imaging showed an intra-articular bioabsorbable interference screw within his intercondylar notch. The screw was retrieved arthroscopically. The graft was intact and functional except for a small portion of the anterior fibers, which were debrided. The patient returned to full activities without complaints.

Arthroscopic treatment of soft-tissue impingement of the ankle in athletes.

Sixty ankle arthroscopies were performed on patients with chronic soft-tissue impingement of the ankle after an ankle sprain between January 1989 and January 1994. Preoperative examination findings featured tenderness localized to the anterolateral aspect of the ankle, no instability, and, with the exception of 2 patients, normal radiographs. A preoperative bone scan was performed on 34 patients and was positive in each case but was not specific. Arthroscopy was performed an average of 23 months after injury. Results were determined by using a new ankle rating score. Hypertrophic synovium, synovitis, or fibrous adhesions were arthroscopically visualized and resected in all cases. The average follow-up was 27 months (range, 6 to 64 months). Thirty-one patients underwent complete evaluation and 29 were evaluated over the telephone. There were 51 excellent, 7 good, 1 fair, and 1 poor results. The diagnosis of chronic soft-tissue impingement of the ankle can be made from an appropriate history, thorough physical examination, and plain radiographs. Ankle arthroscopy with resection of impinging hypertrophic synovium or fibrous bands occurring after an ankle sprain was effective in alleviating pain in athletes.

Arthroscopic stabilization of acute initial anterior shoulder dislocation: the West Point experience.

Arthroscopic stabilization for acute initial shoulder dislocation has been the subject of thorough investigation at West Point over the past decade in an attempt to improve on the natural history of shoulder instability in our young athletic population. From January 1986 to December 1995, 127 patients were treated for acute initial shoulder dislocation at the United States Military Academy. Of the 55 patients treated nonoperatively, 47 (85%) have had recurrence of instability. Seventy-two patients were treated operatively during three separate phases in the evolution of arthroscopic management at our institution. The initial phase (1986 to 1988) of operative treatment included either arthroscopic abrasion or staple repair. The low recurrence rate (2 of 9) was promising. In the operative technique for the second phase (1988 to 1991) transglenoid sutures were used. Of the 21 patients treated in this manner, 18 (86%) had no recurrent instability at last follow-up (average, 32 months). In the third phase (1991 to 1993), patients were treated with a bioabsorbable tack and interscalene anesthesia, and in the sitting position. Thus far, 39 of the latest 42 cadetathletes with acute initial anterior shoulder dislocations have had stabilization with this bioabsorbable cannulated fixation device. The average age was 19.5 years (range, 17 to 23 years). Follow-up averaged 22 months. There were no perioperative complications. Of these 39 patients, 35 (90%) have a stable shoulder and have returned to preinjury performance status. One of 2 patients with recurrent subluxation and 1 of 2 patients with a traumatic redislocation required an open Bankart repair. In young athletes known to have high recurrence rates with nonoperative treatment, acute arthroscopic stabilization appears to be an effective minimally invasive treatment option that favorably alters the natural history of shoulder instability.

Olecranization of the patella.

Olecranization of the patella is a technique employed by some to maintain the normal anatomic relationship of the femorotibial articulation following posterior cruciate ligament (PCL) repairs and reconstructions. It involves temporarily placing a large diameter pin longitudinally through the patella and into the tibia. The patella thus becomes a bony shelf and, in theory, holds the tibia forward, protecting the knee from a posterior drawer force. This technique appears desirable in that it allows postoperative knee motion while theoretically affording protection to the PCL. Unfortunately, it is based on an erroneous concept that the spatial relationship of the patella and tibia remains constant throughout knee flexion. Negative experience at our institution with this technique prompted our investigation. Using lateral radiographs of 20 normal knees taken at four different positions of flexion, we studied the relative motion that occurs between the patella and tibia in the sagittal plane during knee flexion from 0 degrees to 90 degrees, and defined two separate arcs of patellar motion. The patellar tendon arc is a 30 degree arc through which the patella traverses relative to the tibia during knee flexion. The patellar arc is a 22 degree arc on which the patella flexes relative to itself during knee flexion. We also studied the effect that olecranization of the patella has on the PCL in six cadaver knees. Using a combination of direct tension measurement, radiographic measurement, and fluoroscopy, we found that olecranization of the patella not only fails to protect the PCL, but actually induces a detrimental posterior drawer force during knee flexion.(ABSTRACT TRUNCATED AT 250 WORDS)

Shoulder impingement syndrome: diagnostic accuracy of magnetic resonance imaging and radiographic signs.

Shoulder impingement syndrome is commonly encountered in orthopaedics. In a blinded retrospective study, magnetic resonance imaging and roentgenographic signs in 41 patients with clinical signs of impingement syndrome were compared with 40 control patients. Statistically significant differences between the groups included the absence of subarcromial fat, as well as the presence of a supraspinatus tear, subacromial osteophytes, and a decreased coracohumeral distance. Other signs reported to occur in patients with impingement syndrome did not vary significantly in the population studied.