Association Between Anteromedial Portal Versus Tibial Tunnel Drilling and Meniscal Reoperation Risk Following Anterior Cruciate Ligament Reconstruction: A Cohort Study.

BACKGROUND: Anterior cruciate ligament reconstruction (ACLR) provides functional stability to an injured knee. While multiple techniques can be used to drill the femoral tunnel during ACLR, a single technique has yet to be proven as clinically superior. One marker of postoperative functional stability is subsequent meniscal tears; a lower risk of subsequent meniscal surgery could be expected with improved knee stability. PURPOSE: To determine if there is a meniscal protective effect when using an anteromedial portal (AMP) femoral tunnel drilling technique versus transtibial (TT) drilling. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Data from Kaiser Permanente's ACLR registry were used to identify patients who had a primary isolated ACLR between 2009 and 2018; those with previous surgery in the index knee and meniscal pathology at the time of ACLR were excluded. The exposure of interest was TT (n = 2711) versus AMP (n = 5172) drilling. Multivariable Cox proportional hazard regression was used to evaluate the risk of a subsequent ipsilateral meniscal reoperation with adjustment for age, sex, femoral fixation, and graft choice. We observed a shift in surgeon practice from the TT to AMP over the study time frame; therefore, the relationship between technique and surgeon experience on meniscal reoperation was evaluated using an interaction term in the model. RESULTS: At the 9-year follow-up, the crude cumulative meniscal reoperation probability for AMP procedures was 7.76%, while for TT it was 5.88%. After adjustment for covariates, we observed a higher risk for meniscal reoperation with AMP compared with TT (hazard ratio [HR], 1.53; 95% CI, 1.05-2.23). When stratifying by surgeon experience, this adverse association was observed for patients who had their procedure performed by surgeons with less AMP experience (no previous AMP ACLR: HR, 1.26; 95% CI, 0.84-1.91) while a protective association was observed for patients who had their procedure with more experienced surgeons (40 previous AMP ACLRs: HR, 0.34; 95% CI, 0.13-0.92). CONCLUSION: Drilling the femoral tunnel via the AMP was associated with a higher risk of subsequent meniscal surgery compared with TT drilling. However, when AMP drilling was used by surgeons experienced with the technique, a meniscal protective effect was observed.

Femoral Tunnel Drilling Method: Risk of Reoperation and Revision After Anterior Cruciate Ligament Reconstruction.

BACKGROUND: The femoral tunnel in anterior cruciate ligament reconstruction (ACLR) can be created by the transtibial (TT) or tibial-independent (TI) methods. An anatomically located femoral tunnel can be more consistently achieved by TI methods, which include the anteromedial portal and lateral (outside-in, retrodrill) techniques. Nonanatomic graft placement in ACLR can result in postoperative instability and meniscal or chondral injury. An anatomically located graft is subjected to higher postoperative physiologic forces than one placed nonanatomically. PURPOSE: To examine isolated primary ACLR and determine the risk of aseptic revision and reoperation based on femoral tunnel drilling method. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: The ACLR registry of an integrated US health care system was used to identify primary isolated unilateral ACLRs from 2009 to 2014. Multivariable Cox proportional hazard regression models were used to evaluate risk for aseptic revision for graft failure and aseptic reoperation for meniscal or chondral injury according to femoral tunnel drilling method: TI versus TT. Models included age, sex, body mass index (BMI), race, graft type, and femoral fixation type as covariates. RESULTS: The cohort included 19,059 patients with primary ACLR. The mean age was 28.9 years (SD, 11.5), 6991 patients (36.8%) were younger than 22 years, 11,795 patients (61.9%) were male, 7648 patients (40.1%) had a BMI less than 25 kg/m2, 8913 patients (46.8%) were white, and 7357 patients (38.6%) received an allograft. Median follow-up was 2.30 years (interquartile range, 1.08-3.77). TI techniques were used for 12,342 (64.8%) of the ACLRs, and the TT method was used for 6717 (35.2%). Use of TI techniques increased from 33.6% of all ACLRs in 2009 to 83.4% in 2014. After adjustment for covariates, the TI group had a higher risk for aseptic revision than the TT group (hazard ratio [HR], 1.28; 95% CI, 1.04-1.56), and this risk was 1.41 times higher in patients younger than 22 years specifically. The 5-year cumulative reoperation probability was lower in the TI group (4.50%; 95% CI, 3.78%-5.36%) compared with the TT group (5.06%; 95% CI, 4.31-5.94%). After adjustment for the covariates, no difference in risk for aseptic reoperation was observed (HR, 1.08; 95% CI, 0.85-1.39). CONCLUSION: In the largest known study of its type examining femoral tunnel drilling method for primary ACLR, after adjustment for age, sex, BMI, race, graft type, and femoral fixation, TI techniques were found to carry higher risk of aseptic revision compared with the TT method, while no difference was observed in risk for aseptic reoperation.

Revision Risk After Allograft Anterior Cruciate Ligament Reconstruction: Association With Graft Processing Techniques, Patient Characteristics, and Graft Type.

BACKGROUND: Allograft tissue is a common graft choice for anterior cruciate ligament reconstruction (ACLR). Allograft sterilization methods vary widely across numerous commercial tissue vendors. Multiple studies, despite being limited in sample size, have suggested a higher rate of clinical failure associated with the use of allograft tissue in ACLR when compared with autograft. PURPOSE: To examine the association of graft processing techniques, patient characteristics, and graft type with risk of revision surgery after allograft ACLR. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective cohort study was conducted that used an integrated United States health care system's ACLR registry to identify primary unilateral cases in which allografts were used. Aseptic revision was the endpoint of the study. Allograft type, processing methods (irradiation dose, AlloWash, AlloTrue, BioCleanse), and graft donor age were assessed as potential risk factors for revision, with adjustment for patient age, sex, and body mass index (BMI) by use of survival analysis. Hazard ratios (HR) and 95% confidence intervals (CIs) were calculated. RESULTS: A total of 5968 primary ACLR cases with allograft were included in the study, of which 3688 (61.8%) were male patients. The median age of the cohort at the time of surgery was 34.1 years (interquartile range, 24.1-42.9 years). The mean time to follow-up (±SD) was 2.1 ± 1.5 years. There were 3751 (62.9%) allograft ACLRs using soft tissue, 1188 (19.9%) with Achilles tendon, and 1029 (17.2%) with bone-patellar tendon-bone (BPTB). Graft processing groups included BioCleanse (n = 367), AlloTrue or AlloWash (n = 2278), irradiation greater than 1.8 Mrad (n = 1146), irradiation up to 1.8 Mrad (n = 3637), and no irradiation (n = 1185). There were 156 (2.6%) aseptic revisions. After adjustment for patient age, sex, and BMI, the use of BioCleanse (HR = 2.45; 95% CI, 1.36-4.40) and irradiation greater than 1.8 Mrad (HR = 1.64; 95% CI, 1.08-2.49) were associated with a higher risk of revision when compared with all other methods of processing. BPTB allografts were at higher risk of revision (HR = 1.79; 95% CI, 1.20-2.66) when compared with soft tissue allografts. Conversely, with every 5-year increase in age, the risk of revision was 0.67 (95% CI, 0.61-0.73) times lower. Male patients were found to be at higher risk of revision when compared with females (HR = 1.47; 95% CI, 1.04-2.07). The use of AlloWash or AlloTrue processing, patient BMI, and graft donor age did not affect revision rate significantly. CONCLUSION: In the largest known study of its kind examining outcome after primary allograft ACLR, graft irradiation greater than 1.8 Mrad, BioCleanse graft processing, younger patient age, male patients, and BPTB allograft were all associated with a higher risk of clinical failure and subsequent revision surgery.

Arthroscopic capsulolabral reconstruction for posterior instability of the shoulder: a prospective study of 200 shoulders.

BACKGROUND: There are few reports in the literature detailing the arthroscopic treatment of unidirectional posterior shoulder instability. HYPOTHESIS: Arthroscopic capsulolabral reconstruction is effective in restoring stability and function and alleviating pain in athletes with symptomatic unidirectional posterior instability. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: One hundred eighty-three athletes (200 shoulders) with unidirectional recurrent posterior shoulder instability were treated with arthroscopic posterior capsulolabral reconstruction and underwent an evaluation at a mean of 36 months postoperatively. A subset of 117 shoulders of contact athletes was compared with the entire group of 200 shoulders. Patients were evaluated prospectively with the American Shoulder and Elbow Surgeons (ASES) scoring system. Stability, strength, and range of motion were evaluated preoperatively and postoperatively with standardized subjective scales. Methods of intraoperative soft tissue fixation as well as anchorless (n = 44) and anchored (n = 156) plications were recorded for each patient. RESULTS: At a mean of 36 months postoperatively, the mean ASES score improved from 45.9 to 85.1 (P < .001). There were also significant improvements in stability, pain, and function based on previously used scales (P < .001). The contact athletes did not demonstrate any significant differences when compared with the entire cohort for any outcome measure. With regard to the method of internal fixation, patients who underwent capsulolabral plications with suture-anchors showed significantly greater improvement in ASES scores (P < .001) and a higher rate of return to play (P < .05) when compared with patients with anchorless capsulolabral plications. CONCLUSION: Arthroscopic capsulolabral reconstruction is an effective, reliable treatment for symptomatic, unidirectional recurrent posterior glenohumeral instability in an athletic population. Overall, 90% of patients were able to return to sport, with 64% of patients able to return to the same level postoperatively. With the incorporation of bone suture-anchors in capsulolabral reconstruction, patients had greater improvements in ASES scores and a higher rate of return to play.

All-inside patellar tendon anterior cruciate ligament reconstruction.

In the continued evolution of arthroscopic surgery for anterior cruciate ligament (ACL) reconstruction, the "All-Inside" technique has been developed in an attempt to further decrease surgical trauma. By replicating standard anatomic ACL reconstruction techniques, the RetroConstruction System (Arthrex, Naples, FL) eliminates tibial tunnels by creating "Retrodrilled" sockets. This All-Inside technique reduces the size and number of incisions and associated soft-tissue trauma, while eliminating the violation of distal cortices, thereby potentially decreasing patient morbidity, facilitating rehabilitation, and improving cosmesis. The technique is suitable for numerous graft options and can be used either in primary, revision augmentation, or multiligament reconstructions. The rationale and technique for All-Inside bone-patellar tendon-bone autograft or allograft single-bundle ACL reconstruction is presented.

Arthroscopic capsulolabral repair for posterior shoulder instability in throwing athletes compared with nonthrowing athletes.

BACKGROUND: There are limited studies evaluating arthroscopic treatment of unidirectional posterior shoulder instability in overhead-throwing athletes. HYPOTHESIS: Arthroscopic capsulolabral repair for unidirectional posterior shoulder instability will yield equivalent stability and functional outcomes in the overhead-throwing athlete and nonthrowers. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Ninety-eight athletes (107 shoulders) with unidirectional posterior shoulder instability were treated with arthroscopic posterior capsulolabral reconstruction or, rarely, capsular plication alone, as determined by their specific intra-articular lesions. Patients were evaluated prospectively with the American Shoulder and Elbow Surgeons scoring system. Stability, range of motion, strength, pain, and function were assessed preoperatively and postoperatively with standardized subjective scales. Results for 27 dominant shoulders in throwing athletes (25%) were compared with those for 80 shoulders in nonthrowing athletes (75%). RESULTS: At a mean follow-up of 27 months postoperatively, there were no differences in the American Shoulder and Elbow Surgeons score or scores for stability, range of motion, strength, pain, and function between the throwers and nonthrowers, with both groups showing a significant improvement in all categories (P < .0001). Excellent or good results were achieved in 89% of the throwers and 93% of the nonthrowers. Throwing athletes were less likely to return to their preinjury levels of sport (55%) compared with nonthrowing athletes (71%). CONCLUSION: Arthroscopic posterior capsulolabral repair effectively improves stability, range of motion, strength, pain, and function in throwing athletes with unidirectional posterior shoulder instability. Despite similar outcome measures to nonthrowers, throwing athletes are less likely to return to their preinjury levels of sport.

Soft tissue allograft and double-bundle reconstruction.

The anterior cruciate ligament (ACL) is composed of two functional bundles, the anteromedial and posterolateral. Multiple biomechanical and clinical studies have demonstrated that the posterolateral bundle plays a critical role in rotatory stability of the knee. Anatomic double-bundle reconstruction of the ACL best restores knee function and kinematics when the ACL is ruptured. For double-bundle ACL reconstruction, the use of allograft is safe, minimizes graft harvest morbidity, expedites recovery, and is associated with successful clinical results in short-term follow-up.

Arthroscopic capsulolabral reconstruction of the type VIII superior labrum anterior posterior lesion: mean 2-year follow-up on 13 shoulders.

BACKGROUND: A type VIII superior labrum anterior posterior lesion represents pathologic posteroinferior extension of a type II superior labrum anterior posterior lesion with injury to the insertion of the posterior band of the inferior glenohumeral ligament. No reports in the literature describe arthroscopic treatment of a type VIII superior labrum anterior posterior lesion and its associated glenohumeral instability. HYPOTHESIS: Arthroscopic capsulolabral reconstruction is effective in alleviating pain and restoring stability and function in athletes with glenohumeral instability due to the type VIII superior labrum anterior posterior lesion. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: From 2003 to 2006, 23 shoulders in 23 athletes were diagnosed with a type VIII superior labrum anterior posterior lesion by physical examination, magnetic resonance arthrography, and arthroscopy. All were treated with an arthroscopic capsulolabral reconstruction. Ten patients were involved in rehabilitation less than 9 months after surgery and were not included in this study. Thirteen remaining shoulders in 13 athletes with a mean age of 27.8 +/- 10.9 years were analyzed at a mean follow-up of 24 months. Shoulders were evaluated preoperatively and postoperatively using the American Shoulder and Elbow Surgeons scoring system and standard subjective scales for stability, strength, function, and range of motion. RESULTS: Athletes most commonly participated in sport at the recreational level (n = 8), followed by collegiate (n = 3) and high school (n = 2). The most common activity was weight lifting (n = 4). Eight athletes (62%) participated in contact sports, most commonly football and wrestling. Two patients (15%) had a partial-thickness articular-sided supraspinatus tendon tear that was debrided at the time of surgery. Mean American Shoulder and Elbow Surgeons score improved from 51.4 to 90.0 (P < .001). There were significant improvements in stability, pain, function, and range of motion based on standardized subjective scales (P < .001). No shoulder required revision surgery for recurrent instability. All patients were able to return to sports, with 9 (69%) able to return to their highest level before surgery. CONCLUSION: Arthroscopic capsulolabral reconstruction is an effective and reliable treatment for glenohumeral instability due to a type VIII superior labrum anterior posterior lesion in the contact, noncontact, and throwing athlete. Successful postoperative return to sport is a reasonable expectation.

Management of Morel-Lavallee lesion of the knee: twenty-seven cases in the national football league.

BACKGROUND: The Morel-Lavallee lesion is a closed degloving injury most commonly described in the region of the hip joint after blunt trauma. It also occurs in the knee as a result of shearing trauma during football and is a distinct lesion from prepatellar bursitis and quadriceps contusion. PURPOSE: To review the authors' experience with Morel-Lavallee lesion of the knee in the elite contact athlete to construct a diagnostic and treatment algorithm. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty-seven knees in 24 players were identified from 1 National Football League team's annual injury database as having sustained a Morel-Lavallee lesion between 1993 and 2006. Their charts were retrospectively reviewed. RESULTS: The most common mechanism of injury was a shearing blow on the playing surface (81%). The most common motion deficit was active flexion (41%). The mean time for resolution of the fluid collection and achievement of full active flexion was 16.3 days. The mean number of practices missed was 1.5. The mean number of games missed was 0.1. Fourteen knees (52%) were treated successfully with compression wrap, cryotherapy, and motion exercises. Thirteen knees (48%) were treated with at least 1 aspiration, and 6 knees (22%) were treated with multiple aspirations for recurrent serosanguineous fluid collections. In 3 cases (11%), the Morel-Lavallee lesion was successfully treated with doxycycline sclerodesis after 3 aspirations failed to resolve the recurrent fluid collections; return to play was immediate thereafter in each case. CONCLUSION: In football, Morel-Lavallee lesion of the knee usually occurs from a shearing blow from the playing field. Diagnosis is confirmed when examination reveals a large suprapatellar area of palpable fluctuance. Elite athletes are typically able to return to practice and game play long before complete resolution of the lesion. Recurrent fluid collections can occur, necessitating aspiration in approximately half the cases for successful treatment. Recalcitrant fluid collections can be safely and expeditiously treated with doxycycline sclerodesis.

Changes in knee laxity and ligament force after sectioning the posteromedial bundle of the posterior cruciate ligament.

PURPOSE: Our purpose was to evaluate the role of the posteromedial (PM) bundle of the native posterior cruciate ligament (PCL) in restraining posterior tibial translation and the effects of sectioning of the PM bundle on PCL forces. METHODS: The PCL's femoral origin was mechanically isolated by use of a cylindrical coring cutter, and a cap of bone containing the ligament fibers was attached to a load cell that recorded resultant force in the ligament as the knee was passively extended from 120 degrees to 0 degrees without and with simulated tibial loading conditions. Anteroposterior laxity was also measured after load cell installation. The PM bundle was cut at its femoral origin, and all tests were repeated. RESULTS: Cutting the PM bundle produced small but statistically significant increases in mean laxity at 0 degrees (+1.06 mm) and 10 degrees (+0.83 mm) of flexion; mean laxities at 30 degrees, 45 degrees, 70 degrees, and 90 degrees were unchanged. Forces in the remaining anterolateral bundle were not significantly different from those in the intact ligament for any mode of tibial loading, with the exception of the valgus moment, where sectioning of the PM bundle significantly reduced the PCL force at 0 degrees and 5 degrees of flexion. CONCLUSIONS: The relatively small increases in mean laxity after cutting of the PM bundle show that it plays a minor role in restraining posterior tibial translation. The minor changes in ligament force profiles after cutting of the PM bundle indicate that the remaining anterolateral bundle fibers continued to be loaded in a near-normal fashion. CLINICAL RELEVANCE: This study helps to elucidate the function of the PM bundle in the native PCL. Because only small changes were seen in the biomechanical parameters tested, the rationale for reconstructing this bundle of the PCL could be questioned.

Transient meralgia paresthetica after pediatric posterior spine fusion.

Meralgia paresthetica (MP) rarely occurs during posterior spine surgery. The study goal was to examine risk factors associated with the incidence of MP. A review of 56 consecutive pediatric patients undergoing posterior spine fusion for scoliosis was performed. Patients with abnormal sensation in the lateral thigh preoperatively and prior spine surgery were excluded. All patients were positioned prone on the Jackson (Orthopaedic Systems, Inc., Union City, CA) spinal table with either (1) the lower leg support table and thigh supports or (2) the lower leg suspension sling. Data on patient weight, diagnosis, surgeon, duration of surgery, presence of MP, symptoms, and symptom duration were collected. A logistic regression analysis was performed between independent variables and presence of MP. There were 10/56 patients with MP (18%). Symptoms were anterolateral thigh numbness without pain or weakness. Symptoms in all cases were resolved, on average, before the 6-week postoperative visit (range 2-24 weeks). Patients with MP more often had idiopathic scoliosis (28% vs 7%; P < 0.05) were positioned with the lower leg sling instead of the flat table support (31% vs 13%; P < 0.05) and trended toward longer surgery times (451 vs 388 minutes; NS). Abnormal body mass index, age at surgery, surgeon, and sex did not correlate to MP. MP can occur after pediatric posterior spine surgery. Symptoms were minor, temporary, and did not require treatment. Shorter surgical times and use of thigh pads in conjunction with the lower leg support table may decrease the incidence of MP.

Reconstruction of the interosseous membrane of the forearm with a graft substitute: a cadaveric study.

PURPOSE: Longitudinal radioulnar dissociation occurs when traumatic axial loading through the wrist disrupts the interosseous membrane (IOM) of the forearm and fractures the radial head (Essex-Lopresti injury). Proximal migration of the radius results in a wrist with a positive ulnar variance, which leads ultimately to painful ulnar-sided wrist degeneration and wrist pain during grasping activities that involve axial loading or ulnar deviation of the wrist. In theory reconstruction of the IOM with a graft substitute can limit proximal migration of the radius, thereby preserving wrist function. The objective of this study was to measure the abilities of 3 graft tissues to limit proximal radial displacement compared with the native IOM in a radial head-deficient cadaver model. METHODS: Sixteen fresh-frozen cadaveric forearms were loaded axially to 134 N through the potted central 3 metacarpals; the elbow was flexed to 90 degrees with the wrist in neutral rotation. Proximal displacement of the radius relative to the capitellum was measured. With the radial head excised specimens were first tested with the IOM intact. The IOM was then sectioned and central band IOM reconstructions were performed on each specimen using the following tissues: palmaris longus tendon, flexor carpi radialis (FCR) tendon, and a 1-cm- wide bone-patellar tendon-bone (BPTB) onlay allograft. Ten loading cycles were performed with each test configuration. Proximal radial displacement between 13.4 N and 134 N of applied wrist force was analyzed for the 10th loading cycle. The increase in proximal displacement between the first and 10th loading cycles (recorded at 134 N of wrist force) represented permanent elongation of the graft. RESULTS: Mean cross-sectional areas were 5.11 mm2 for the palmaris longus tendon, 15.23 mm2 for the FCR tendon, and 51.59 mm2 for the BPTB allograft. Mean proximal radial displacements were 3.04 mm (intact IOM), 4.37 mm (BPTB), 4.92 mm (FCR tendon), and 6.43 mm (palmaris tendon); all means were significantly different from each other. Mean permanent graft elongations were 0.06 mm (IOM), 0.36 mm (BPTB), 1.25 mm (FCR tendon), and 1.80 mm (palmaris tendon); all means were significantly different from each other with the exception of means for palmaris longus vs FCR and BPTB vs IOM. CONCLUSIONS: No graft reconstruction limited proximal radial displacement as effectively as the native IOM. Of the 3 graft tissues tested the BPTB allograft had the greatest cross-sectional area, allowed the least proximal radial displacement, and displayed the least permanent elongation after 10 cycles of loading. The relatively thin and narrow palmaris longus tendon appears to be the least desirable choice for IOM reconstruction because of its relatively low stiffness and tendency to elongate permanently after cyclic loading. When the radial head is absent rupture of the IOM allows unopposed proximal displacement of the radius relative to the ulna as the wrist is loaded axially. In the present tests all 3 graft tissues used to reconstruct the IOM limited proximal radial displacement. The choice of graft material is an important variable if IOM reconstruction is considered for treatment of an Essex-Lopresti injury.

Graft reconstruction of the interosseous membrane in conjunction with metallic radial head replacement: a cadaveric study.

PURPOSE: Longitudinal radioulnar dissociation (Essex-Lopresti injury) occurs when traumatic axial loading through the wrist disrupts the interosseous membrane (IOM) of the forearm and fractures the radial head. Proximal migration of the radius results in an ulnar-positive wrist, which can lead to painful ulnar-sided wrist degeneration and distal radioulnar joint instability. The purpose of this study was to measure the ability of an IOM reconstruction used in combination with a metal prosthetic radial head implant to reduce distal ulnar forces in a cadaveric model. The effects of varying the initial graft pretension on distal ulnar force were also studied. METHODS: Twelve fresh frozen and thawed cadaveric forearms had a miniature load cell installed to record force in the distal ulna as the wrist was loaded axially to 134 N of compression force in neutral rotation. Intact forearms were tested first with the elbow in valgus and varus alignments. Loading tests were repeated after (1) insertion of a metal radial head implant that restored radius anatomic length, (2) excision of the IOM (with a radial head implant), and (3) reconstruction of the IOM using a palmaris longus tendon autograft (with a radial head implant). The implant then was removed and loading tests were repeated using 3 levels of initial graft pretension. RESULTS: Mean distal ulnar forces with an intact forearm were 23% of applied wrist force in the varus alignment and 12% in the valgus alignment. Mean force levels after insertion of the implant were 18% (varus) and 13% (valgus); these were not significantly different from corresponding values for the intact forearm. Mean force levels after section of the IOM were 30% (varus) and 14% (valgus); these were not significantly different from corresponding values for the intact forearm (varus and valgus) but the mean for varus was significantly greater than the corresponding value with an implant. After IOM reconstruction with a palmaris longus tendon tensioned to 22 N mean distal ulnar forces were 8% (varus) and 7% (valgus); these means were significantly less than the corresponding values for all prior test conditions. With the radial head removed increasing the level of graft pretension reduced significantly mean distal ulnar force. CONCLUSIONS: With the IOM resected insertion of a metal radial head implant alone did not reduce distal ulnar forces to intact forearm levels. When an IOM reconstruction was performed in combination with the implant mean distal ulnar force was reduced significantly to a level below that for the intact forearm. Applying pretension to the graft displaced the radius distally thereby making the wrist more ulnar negative and reducing distal ulnar force. Our results suggest that an IOM reconstruction used in combination with a metal radial head implant theoretically could help reduce distal ulnar impaction in an Essex-Lopresti injury.

Effects of wafer resection and hemiresection from the distal ulna on load-sharing at the wrist: a cadaveric study.

PURPOSE: Ulnar impaction syndrome is commonly the result of a naturally occurring ulnar-positive condition, distal radius fracture malunion, or collapse of a fractured radial head. The Feldon wafer procedure and the Bowers distal hemiresection procedure are designed to decrease force transmitted through the distal ulna. The purpose of this study was to measure the effects of these procedures on distal ulnar loading with varying degrees of ulnar positivity at the wrist. METHODS: Using a specially designed miniature load cell distal ulnar force was measured in 20 fresh-frozen cadaveric forearms as the wrist was loaded axially to 134 N in neutral forearm rotation; tests were performed in valgus alignment with the elbow flexed to 90 degrees . Ulnar positivity (0 mm, +2 mm, +4 mm, and +6 mm) was created by incremental shortening of the distal radius using a sliding plate. The radial neck was sectioned transversely and the radial head fragment was fixed in its anatomic position using cemented metal prongs connected to a rigid bar; this allowed the radial head to be disconnected and tilted out of the loading pathway to simulate an excised radial head. Loading tests (with and without the radial head in place) were repeated after removal of a 3-mm wafer of bone beneath the triangular fibrocartilage complex, and again after a hemiresection of the distal ulna to the base of the ulnar styloid process. RESULTS: For each ulnar status condition (intact, wafer removal, hemiresection) the mean distal ulnar force generally increased as the wrist became more ulnar positive. Both wafer removal and hemiresection significantly decreased mean distal ulnar forces under all conditions of ulnar variance, with or without the radial head in place. With the radial head in place the mean distal ulnar forces (expressed as a percentage of applied wrist force) for the 0-mm condition were 16.9% (intact), 3.8% (wafer removal), and 3.5% (hemiresection); corresponding values for the +6-mm condition were 61.6% (intact), and 39.8% (wafer removal), 15.1% (hemiresection). With the radial head removed the mean distal ulnar forces for the 0-mm condition were 31.7% (intact), 4.6% (wafer removal), and 4.4% (hemiresection); corresponding values for the +6-mm condition were 96.4% (intact), 71.6%, (wafer removal), and 27.2% (hemiresection). The decrease of distal ulnar force resulting from hemiresection was significantly greater than that for wafer removal for all ulnar-positive conditions; force reductions were not significantly different between the 2 procedures with neutral ulnar variance. CONCLUSIONS: The results of the present study can help to offer a biomechanical basis for choosing between a Feldon wafer procedure and a Bowers hemiresection procedure in patients with ulnocarpal impaction syndrome. Both procedures produced equal decreases of distal ulnar force in the intact forearm. With an ulnar-positive wrist, the condition for which the procedure would be performed commonly, the hemiresection was more effective in decreasing force transmitted through the distal ulna.

Subchondral giant-cell tumor of the proximal tibia: arthroscopic treatment for accelerated articular cartilage and meniscal degeneration in two patients.

Giant-cell tumor most commonly occurs in the distal femur and proximal tibia and characteristically involves the subchondral bone. Incomplete resection leads to recurrence rates of up to 50%. Intralesional curettage, adjuvant treatments, and polymethyl methacralate (PMMA) reconstruction is the current mainstay of treatment and has produced recurrence rates of less than 10%. Achieving adequate curettage while preserving the articular cartilage of the tibial plateau poses a significant challenge, especially when the tumor involves the subchondral bone. We report on 2 cases, both with symptomatic full-thickness tibial articular cartilage loss and one with a meniscal tear, after curettage, phenol cautery, and PMMA reconstruction of giant-cell tumor of the proximal tibia. Arthroscopic chondroplasty and planing of the exposed cement was performed in both cases, theoretically reducing focal areas of stress concentration that could lead to further meniscal damage and injury to the femoral condyle articular surface in weight-bearing. Partial meniscectomy for a complex meniscal tear was performed in one case. Eighteen months postoperatively, both patients were asymptomatic, working full-time, and participating in light physical activity. Repetitive heavy loading of the knee, such as running, was prohibited, and long-term follow-up is warranted to assess for further joint degeneration and need for total knee arthroplasty.

Load-sharing at the wrist following radial head replacement with a metal implant. A cadaveric study.

BACKGROUND: Surgical excision of the radial head is frequently required after a comminuted fracture of the radial head. The outcome of this procedure is often unpredictable, with some patients experiencing ulna-sided pain in the wrist secondary to proximal migration of the radius. Insertion of a radial head prosthesis could prevent proximal radial migration and restore normal load-sharing at the wrist. The thickness of the radial head implant is an important variable in restoring anatomical radial length; however, the effects of varying the length of implants that were used to reconstruct the radius on load-sharing at the wrist have not been studied biomechanically, to our knowledge. METHODS: A miniature load cell was attached to fifteen fresh-frozen cadaveric forearms to record force in the distal part of the ulna as the wrist was axially loaded to 134 N of compression force. Proximal displacement of the radius relative to the capitellum was also recorded. Loading tests on intact forearms were performed with the elbow in valgus and varus alignment and with three positions of wrist rotation (neutral, 45 degrees of pronation, and 45 degrees of supination). Loading tests were then repeated, with the same positions of varus and valgus elbow alignment and wrist rotation as had been used in the tests of the intact forearm, after radial head excision and subsequent insertion of metal radial head implants that restored anatomical length, implants that produced a radial length that was longer than the anatomical length, and implants that produced a radial length that was shorter than the anatomical length. Testing of these different implant thicknesses was repeated after sectioning of the interosseous membrane. RESULTS: The mean distal ulnar forces and mean proximal radial displacements following insertion of an implant that restored anatomical length were not significantly different from the corresponding values for the intact forearm. At neutral wrist rotation, replacing that implant with an implant that increased the radial length by 4 mm (after sectioning of the interosseous membrane) decreased the mean distal ulnar force from 13.4% to 3.3% of the applied wrist force with the elbow in valgus alignment and from 29.1% to 8.6% with the elbow in varus alignment. Replacing the implant that restored anatomical length with one that decreased the length by 4 mm (after sectioning of the interosseous membrane) significantly increased the mean distal ulnar force from 13.4% of the applied wrist load to 33.3% with the elbow in valgus alignment and from 29.1% to 51.6% with it in varus alignment. The mean distal ulnar forces were not significantly affected by the position of wrist rotation when the elbow was in valgus alignment. However, when the elbow was in varus alignment, the mean distal ulnar forces associated with all reconstructed radial lengths were significantly higher when the wrist was placed in 45 degrees of supination. CONCLUSIONS: In this cadaveric model, insertion of a metal implant maintained distal ulnar forces at normal levels, at all three positions of wrist rotation, when the radius had been restored to its original anatomical length. Distal ulnar forces and proximal radial displacements were significantly affected by the reconstructed length of the radius. CLINICAL RELEVANCE: Radial head implants are utilized to prevent proximal migration of the radius as the wrist is loaded; this is especially important when the interosseous membrane has been ruptured and thus cannot help to limit radial displacement. At the time of surgery, comminution and displacement of a radial head fracture may make estimation of the original radial length difficult. Our results demonstrate that, in terms of distal ulnar loading, it is preferable to insert an implant that is too thick rather than too thin.